Very similar to the prior day, a hot and humid air mass was present over the mid-Atlantic on August 11. A lee side surface trough over Pennsylvania again allowed thunderstorms to develop near peak heating.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS PHI wrote it up.
Very similar to the prior day, a hot and humid air mass was present over the mid-Atlantic on August 11. A lee side surface trough over Pennsylvania again allowed thunderstorms to develop near peak heating. With plenty of instability present and storms taking on some degree of organization, a number of instances of damaging wind occurred as storms moved eastward.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Philadelphia/Mount Holly wrote its last area forecast discussion before the first event at Aug 11, 2:44 PM EST, 3 hours 16 minutes earlier.
Area Forecast Discussion
National Weather Service Mount Holly NJ
344 PM EDT Wed Aug 11 2021
.SYNOPSIS...
Bermuda high pressure remains off the Southeast coast. A cold front
slowly approaches from the west and passes through the region late
Saturday. The front becomes nearly stationary over the Mid-Atlantic
as high pressure builds in from the north.
&&
.NEAR TERM /THROUGH THURSDAY/...
A growing threat for severe weather this afternoon with an
amplifying shortwave trough axis ejecting into the Great Lakes.
Currently, an embedded vorticity maximum is crossing central PA,
largely responsible for the MCS feature that moved across the
Pittsburgh Metro over the early afternoon. With locations
reaching their convective temperatures this afternoon, we are
beginning to see convection fire closer to our western CWA
border along various differential heating boundaries. With two
lines of maximized vorticity across Southeast PA into Maryland
and another slightly west of this, expect perhaps two lines of
convection through the mid- afternoon that may congeal into a
more solid line across eastern PA.
Best confidence is for southeastern PA, southwestern NJ, and
northern Delmarva where we just issued a Severe Thunderstorm
Watch through 9:30 pm. Instability is highest with 2000 to 3000
J/kg CAPE values. Unfortunately, DCAPE values are also running
high from 1000 to 1500 J/kg, which is increasing the chance for
wet microbursts. We also need to keep an eye on a strong MCS
across Indiana and Ohio associated with another vorticity
maximum which is moving closer towards the dreaded Derecho
criteria. A few hi-res runs have suggested this potential, which
could pivot south and east into Pennsylvania overnight into the
morning, but it is still unlikely this would directly affect
our region. Just something to watch, nonetheless. With PWATs
nearing 2 inches, torrential rainfall is likely once again this
afternoon like yesterday. Thankfully, storm motion seems
progressive enough to preclude flash flooding. Downbursts should
be the greatest concern this afternoon.
Heat continues to also be a concern with numerous locations
already surpassing heat indices of 105 this afternoon. With
plenty of sunshine ahead of convection to our west, we have room
for another degree or two of heating. With stronger ridging
overhead tomorrow and an increased downslope/westerly component
to the low-level flow, expect temperatures to bump upwards
another degree or two with highs topping out in the low to mid
90s. This also results in heat indices from 106-107 in portions
of the urban corridor.
Similar Thursday convection-wise with a hi-res guidance
supporting the idea that we could see a few bowing lines or an
MCS again, highly-dependent on what happens upstream across the
Great Lakes as previously mentioned.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
Any showers and thunderstorms taper off Thursday night, and
conditions will remain hot and humid through the overnight with lows
in the mid to upper 70s, and around 80 in Philadelphia. The final
day of excessive heat looks to be Friday, but there are some
concerns. Widespread high temperatures will be in the mid to upper
90s, through in the far northern zones, there is some question as to
how warm it will get, as cloud cover could keep temperatures in
the upper 80s to low 90s. Dew points will start out in the mid
to upper 70s before backing off a bit in the afternoon during
the peak heating of the day. Regardless, looks like another day
with widespread heat index values of 105-110. Will go ahead and
expand the Excessive Heat Warning for the urban corridor
counties and for areas east that are currently under the
Warning. Will also extend the Heat Advisories for the north
shore of New Jersey and Delmarva through Friday, as heat index
values will remain below warning criteria in those locations.
The main concern is areas in the Warning through Thursday north
and west of the Fall Line. Although most areas may touch 105, it
is neither as likely nor as widespread as elsewhere due to
cloud cover. Will issue an Excessive Heat Watch for these areas.
For Carbon, Monroe, and Sussex (NJ) counties, will not issue
any heat products for Friday, as it is much less likely.
Thermal trough develops out ahead of an approaching cold front,
but models have backed off on timing of its passage through the
region. Looks more like an evening event, possibly continuing
through the overnight. Weak low pressure looks to pass west of
the region, and the bulk of the activity should be north and
west of the Fall Line.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Cold front slowly works its way east on Saturday, and with mid-
level trough passing to the north, An area of showers and
thunderstorms will become likely over the area during the day.
Dew points remain well in the 70s, and as a result, PWATs will
be in excess of 2 inches. Heavy rain is possible. Temperatures
during the day will be in the 70s and 80s, possibly touching 90
in some spots.
Cold air advection will be underway by Sunday as the front sags
south. Temperatures will be in the 80s with surface dew points
in the 50s and 60s.
Going into the rest of the new week, the cold front remains over
the Mid-Atlantic as surface high pressure builds in from the
north. However, shortwave energy will pass through the region
and will interact with that frontal boundary, keeping at least
chance PoPs in the forecast during this time. It is not looking
to be a washout, and not every place will heave precip each day,
but the chances are there. Temperatures will be at or just shy
of normal for this time of the year.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.
Rest of Today...A broken line of showers and thunderstorms
appears probable to affect the PHL area terminals and north
between roughly 20Z-00Z. Winds southwesterly around 5-10 kts.
High confidence overall.
Tonight...VFR. South to southwesterly winds 5 kts or less. High
confidence.
Thursday...VFR. Southwesterly winds 5-10 kts during the day and
5 kts or less at night. High confidence.
Outlook...
Thursday night...Sub-VFR possible in fog/stratus. Light SW
winds. Moderate confidence.
Friday...Early morning fog/stratus restrictions. Otherwise, VFR.
SHRA/TSRA possible late. SW winds 10 kt or less. Moderate
confidence.
Friday night...Sub-VFR in SHRA/TSRA in the evening, then
CIG/VSBY restrictions possible in fog at night. Light W-SW
winds. Moderate confidence.
Saturday...Early morning fog/stratus restrictions. SHRA/TSRA
likely in the afternoon with sub-VFR conditions. W-NW winds 10
kt or less. Moderate confidence.
Sunday through Monday...Generally VFR. North to northeast wind
5 to 10 knots. Moderate confidence.
&&
.MARINE...
Sub-advisory conditions are forecast through Thursday with
southerly winds from 10 to 15 knots and gusts from 15 to 20
knots. A few gusts may near 25 knots, however. Seas generally
from 2 to 3 feet.
Outlook...
Thursday night through Monday...Prolonged period of sub-SCA
conditions. Showers and thunderstorms possible Friday night,
then likely on Saturday.
Rip currents...
There is a low risk of rip currents through Thursday with south-
southwesterly winds from 10 to 15 knots and waves from 1 to 3 feet
in the surf zone.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Excessive Heat Warning until 8 PM EDT Thursday for PAZ060>062-
101-103-105.
Excessive Heat Watch from Thursday evening through Friday
evening for PAZ060>062-101-103-105.
Heat Advisory until 8 PM EDT Thursday for PAZ054-055.
Excessive Heat Warning until 8 PM EDT Friday for PAZ070-071-
102-104-106.
NJ...Excessive Heat Warning until 8 PM EDT Thursday for NJZ007>009.
Excessive Heat Watch from Thursday evening through Friday
evening for NJZ007>009.
Heat Advisory until 8 PM EDT Friday for NJZ014-016-021>023-026.
Heat Advisory until 8 PM EDT Thursday for NJZ001.
Excessive Heat Warning until 8 PM EDT Friday for NJZ010-012-
013-015-017>020-027.
DE...Heat Advisory until 8 PM EDT Friday for DEZ002-003.
Excessive Heat Warning until 8 PM EDT Friday for DEZ001.
MD...Heat Advisory until 8 PM EDT Friday for MDZ012-015-019-020.
MARINE...None.
&&
Synopsis...MPS
Near Term...Davis
Short Term...MPS
Long Term...MPS
Aviation...Davis/MPS
Marine...Davis/MPSHazardous Weather Outlook National Weather Service Mount Holly NJ 0601 PM EDT Wed Aug 11 2021 DEZ001-122201- New Castle- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for New Castle County in Delaware. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. DEZ002-122201- Kent- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Kent County in Delaware. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. DEZ003-122201- Inland Sussex- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for inland portions of Sussex County in Delaware. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. DEZ004-122201- Delaware Beaches- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for the Atlantic coastal portions of Sussex County in Delaware. .DAY ONE...Through tonight. The probability for widespread hazardous weather is low. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. PAZ054-122201- Carbon- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Carbon County in Pennsylvania. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. PAZ055-122201- Monroe- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Monroe County in Pennsylvania. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. PAZ060-122201- Berks- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Berks County in Pennsylvania. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Excessive Heat Watch. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. PAZ061-122201- Lehigh- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Lehigh County in Pennsylvania. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Excessive Heat Watch. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. PAZ062-122201- Northampton- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Northampton County in Pennsylvania. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Excessive Heat Watch. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. PAZ070-122201- Delaware- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Delaware County in Pennsylvania. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. PAZ071-122201- Philadelphia- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Philadelphia County in Pennsylvania. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. PAZ101-122201- Western Chester- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for western Chester County in Pennsylvania. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Excessive Heat Watch. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. PAZ102-122201- Eastern Chester- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for eastern Chester County in Pennsylvania. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. PAZ103-122201- Western Montgomery- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for western Montgomery County in Pennsylvania. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Excessive Heat Watch. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. PAZ104-122201- Eastern Montgomery- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for eastern Montgomery County in Pennsylvania. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. PAZ105-122201- Upper Bucks- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for upper Bucks County in Pennsylvania. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Excessive Heat Watch. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. PAZ106-122201- Lower Bucks- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for lower Bucks County in Pennsylvania. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. NJZ001-122201- Sussex- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Sussex County in New Jersey. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. NJZ007-122201- Warren- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Warren County in New Jersey. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Excessive Heat Watch. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. NJZ008-122201- Morris- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Morris County in New Jersey. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Excessive Heat Watch. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. NJZ009-122201- Hunterdon- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Hunterdon County in New Jersey. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Excessive Heat Watch. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. NJZ010-122201- Somerset- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Somerset County in New Jersey. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. NJZ012-122201- Middlesex- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Middlesex County in New Jersey. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. NJZ013-122201- Western Monmouth- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for western Monmouth County in New Jersey. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. NJZ014-122201- Eastern Monmouth- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for eastern Monmouth County in New Jersey. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. NJZ015-122201- Mercer- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Mercer County in New Jersey. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. NJZ016-122201- Salem- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Salem County in New Jersey. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. NJZ017-122201- Gloucester- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Gloucester County in New Jersey. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. NJZ018-122201- Camden- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Camden County in New Jersey. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. NJZ019-122201- Northwestern Burlington- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for northwestern Burlington County in New Jersey. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. NJZ020-122201- Ocean- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for inland portions of Ocean County in New Jersey. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. NJZ021-122201- Cumberland- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Cumberland County in New Jersey. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. NJZ022-122201- Atlantic- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for inland portions of Atlantic County in New Jersey. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. NJZ023-122201- Cape May- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Cape May County excluding the Atlantic coast in New Jersey. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. NJZ024-122201- Atlantic Coastal Cape May- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for the Atlantic coastal portions of Cape May County in New Jersey. .DAY ONE...Through tonight. The probability for widespread hazardous weather is low. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. NJZ025-122201- Coastal Atlantic- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for coastal portions of Atlantic County in New Jersey. .DAY ONE...Through tonight. The probability for widespread hazardous weather is low. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. NJZ026-122201- Coastal Ocean- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for coastal portions of Ocean County in New Jersey. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. NJZ027-122201- Southeastern Burlington- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for southeastern Burlington County in New Jersey. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Excessive Heat Warning. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. MDZ012-122201- Kent MD- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Kent County in Maryland. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. MDZ015-122201- Queen Annes- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Queen Annes County in Maryland. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. MDZ019-122201- Talbot- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Talbot County in Maryland. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. MDZ020-122201- Caroline- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for Caroline County in Maryland. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. ANZ430-122201- Delaware Bay waters north of East Point NJ to Slaughter Beach DE- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for upper Delaware Bay. .DAY ONE...Through tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Severe Thunderstorm Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. ANZ431-122201- Delaware Bay waters south of East Point NJ to Slaughter Beach DE- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for lower Delaware Bay. .DAY ONE...Through tonight. The probability for widespread hazardous weather is low. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. ANZ450-122201- Coastal waters from Sandy Hook to Manasquan Inlet NJ out 20 nm- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for the Atlantic coastal waters adjacent to Monmouth County out 20 nm. .DAY ONE...Through tonight. The probability for widespread hazardous weather is low. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. ANZ451-122201- Coastal waters from Manasquan Inlet to Little Egg Inlet NJ out 20 nm- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for the Atlantic coastal waters adjacent to Ocean County out 20 nm. .DAY ONE...Through tonight. The probability for widespread hazardous weather is low. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. ANZ452-122201- Coastal waters from Little Egg Inlet to Great Egg Inlet NJ out 20 nm- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for the Atlantic coastal waters adjacent to Atlantic County out 20 nm. .DAY ONE...Through tonight. The probability for widespread hazardous weather is low. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. ANZ453-122201- Coastal waters from Great Egg Inlet to Cape May NJ out 20 nm- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for the Atlantic coastal waters adjacent to Cape May County out 20 nm. .DAY ONE...Through tonight. The probability for widespread hazardous weather is low. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. ANZ454-122201- Coastal waters from Cape May NJ to Cape Henlopen DE out 20 nm- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for the Atlantic coastal waters adjacent to the mouth of Delaware Bay out 20 nm. .DAY ONE...Through tonight. The probability for widespread hazardous weather is low. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. ANZ455-122201- Coastal waters from Cape Henlopen to Fenwick Island DE out 20 nm- 0601 PM EDT Wed Aug 11 2021 This Hazardous Weather Outlook is for the Atlantic coastal waters adjacent to Sussex County out 20 nm. .DAY ONE...Through tonight. The probability for widespread hazardous weather is low. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
623 PM EDT WED AUG 11 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0610 PM TSTM WND DMG SPRING TWP 40.32N 76.00W
08/11/2021 BERKS PA LAW ENFORCEMENT
TREES DOWN ON WIRES ON JEFFERSON AVENUE IN
SPRING TOWNSHIP.TIME ESTIMATED FROM RADAR.
&&
NCPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
628 PM EDT WED AUG 11 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0608 PM TSTM WND DMG WEST WYOMISSING 40.32N 75.99W
08/11/2021 BERKS PA TRAINED SPOTTER
HALF OF LARGE MAPLE TREE DOWN ON ROAD. TIME
ESTIMATED FROM RADAR.
&&
NCSpecial Weather Statement
National Weather Service Mount Holly NJ
632 PM EDT Wed Aug 11 2021
NJZ001-007>010-PAZ055-062-112300-
Hunterdon NJ-Morris NJ-Sussex NJ-Somerset NJ-Warren NJ-Monroe PA-
Northampton PA-
632 PM EDT Wed Aug 11 2021
...A cluster of strong thunderstorm will impact portions of northern
Hunterdon, Morris, Sussex, Warren, north central Somerset,
southeastern Monroe and northeastern Northampton Counties through
700 PM EDT...
At 632 PM EDT, Doppler radar was tracking a cluster of strong
thunderstorm near Belvidere, or 16 miles northeast of Easton, moving
northeast at 25 mph.
HAZARD...Winds in excess of 40 mph and pea size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
Locations impacted include...
Morristown, Newton, Montague, Dover, Hopatcong, East Hanover, Lincoln
Park, Kinnelon, East Stroudsburg, Hackettstown, Boonton, Butler,
Wharton, Washington, Rockaway, Blairstown, Morris Plains, Bangor,
Mount Arlington and Franklin.
People at the New Jersey State Fair should seek safe shelter
immediately!
This includes the following highways...
Interstate 78 in New Jersey between mile markers 6 and 15.
Interstate 80 in Pennsylvania between mile markers 307 and 314.
Interstate 80 in New Jersey between mile markers 0 and 49.
Interstate 287 in New Jersey between mile markers 32 and 54.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
A Severe Thunderstorm Watch remains in effect until 900 PM EDT for
northwestern New Jersey...and eastern and northeastern Pennsylvania.
&&
LAT...LON 4120 7436 4110 7449 4104 7450 4105 7445
4102 7443 4100 7430 4090 7427 4091 7434
4086 7432 4080 7436 4060 7504 4091 7535
4115 7514 4114 7509 4108 7503 4109 7500
4116 7490 4129 7483 4135 7475 4136 7469
TIME...MOT...LOC 2232Z 237DEG 20KT 4086 7502
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH
RobertsonPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
639 PM EDT WED AUG 11 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0630 PM TSTM WND DMG 2 W OLEY 40.39N 75.83W
08/11/2021 BERKS PA LAW ENFORCEMENT
TREE DOWN AT VICTORIA LN/BULL ROAD. TIME
ESTIMATED FROM RADAR.
&&
NCPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
641 PM EDT WED AUG 11 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0632 PM TSTM WND DMG 1 NNE OLEY 40.40N 75.79W
08/11/2021 BERKS PA LAW ENFORCEMENT
TREES AND WIRES DOWN IN OLEY TOWNSHIP ON
WATER ROAD. TIME ESTIMATED FROM RADAR.
&&
NCPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
655 PM EDT WED AUG 11 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0648 PM TSTM WND DMG CEDARVILLE 40.23N 75.67W
08/11/2021 CHESTER PA LAW ENFORCEMENT
TREE DOWN AND BLOCKING SHEEPHILL ROAD. TIME
ESTIMATED FROM RADAR.
&&
NCThe Philadelphia radar (KDIX), 112 km away, was scanning. The volume nearest the first event began at 22:57 UTC.
7 thunderstorm wind. Local standard time, as filed.
There were several calls for downed trees and wires in Independence Twp. Time estimated from radar.
Multiple trees and wires were blown down near the intersection of Bilby Rd and Willow Grove St. Time estimated from radar.
There were several downed tree and wire calls in and near Long Valley. Time estimated from radar.
Wires were downed on NJ-10 eastbound near Dover Chester Rd, with lane restrictions. Time estimated from radar.
There were several downed tree and wire calls in and near Randolph. Time estimated from radar.
Several calls for downed trees and wires were made in and near Morristown. Time estimated from radar.
A video was received via social media of a tree down on power lines. Time estimated from radar.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in New Jersey in 2021Every state in 2021This day in weather historyWarnings in New Jersey, August 2021
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 972128, 972129, 972130, 972036, 972131, 972035, 972037.