Thunderstorms brought locally heavy rain to southeastern Pennsylvania on the afternoon of August 12. Rainfall amounts were as high as 2 to 3 inches.
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.
Thunderstorms brought locally heavy rain to southeastern Pennsylvania on the afternoon of August 12. Rainfall amounts were as high as 2 to 3 inches.
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 12, 11:08 AM EST, 2 hours 37 minutes earlier.
Area Forecast Discussion
National Weather Service Mount Holly NJ
1208 PM EDT Wed Aug 12 2020
.SYNOPSIS...
A cold front will move into our area today, and will very slowly
progress southward through the end of the week. Several areas of low
pressure will develop and track along this front through the
weekend, while high pressure will build to our north.
The boundary may return to our area Sunday into early next week as a
low moves through Canada while a second low forms along the boundary
to our south.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Midday Update...
Convective initiation has occurred over the region, mainly right
along the urban corridor as well as over eastern NJ. It's been a hot
and very humid morning with some impressively high dew point values.
This has led to very strong instability (SB CAPE over 4000J/kg!)
developing in the area. So rapid convective growth is possible in
the next couple of hours. Initial storm motions today confirm that
shear is essentially zero. This will limit storm organization and
keep any severe threat relegated to the pulse downburst variety.
However, we have already observed a couple of weak to moderate
downburst signatures on the TPHL radar so a severe downburst or two
is very much possible as storms grow taller. Heavy rainfall and
flash flooding remain the biggest concerns given the slow storm
motions. Overall, no change in the forecast reasoning and things
seem to be developing mostly as expected. Previous discussion
follows...
Morning Update...
No major changes with the morning update. Bumped temperatures up a
little bit for the next couple hours as morning cloudiness has
quickly cleared. Only minor tweaks to PoPs. Continuing to expect
an active hydro day in parts of the area. Convection this
morning was unimpressive overall in our area, and is unlikely to
have had much if any impact on our instability for later today.
Currently thinking the best chance for storms will be right
along the urban corridor and into adjacent portions of southern
NJ, as well as much of Delmarva. In other words, along and just
southeast of the front. See previous discussion below for more
on today's forecast reasoning...
A weak cold front has slowed down over the region this morning,
and appears to be stalling right near the I-95 corridor. As
mentioned by the previous shift, we will have precipitable water
values well above normal along and southeast of the front. As
we have seen the last few days, we will likely have CAPE values
getting near or above 1000 J/kg ahead of the front with little
(if any) CIN. Synoptic scale lift is still quite limited (though
we will be on the fringe of the right entrance region of the
upper level jet by late today into this evening). However, weak
mesoscale lift both along the front and along any sea and bay
breezes should be more than enough for convective initiation.
What is most unusual about today is the wind profiles over the
region. Model soundings show wind speeds 6 kt or less through a deep
layer (from the surface through approximately 450 mb). Consequently
storm motions are going to be very slow (likely 5 mph or less!).
Additionally, this means that bulk shear values in some areas are
near zero.
Bottom line is that with the weak lift and almost negligible shear,
I'm not sure how widespread the coverage of showers and storms will
be. However, for anything that does develop, heavy rain leading to
flash flooding will be a concern.
More details on the thunderstorm hazards:
Heavy rain/flash flooding: Soils across our region remain quite wet
thanks to the rounds of storms (and one tropical storm) from last
week. Most of the region hasn't had sufficient opportunity to dry
out meaning that it will take less rainfall to result in flash
flooding. Also, any storms that develop are barely going to be
moving so rain amounts may vary greatly across the region. In
addition to the high precipitable water values, there should be a
deep warm cloud layer which would further increase the risk of heavy
rain. The potential limited coverage and the lack of moisture
advection during the event are the only factors which could limit
heavy rain threat.
Gusty winds: As mentioned above, shear will be almost negligible,
which will mean we aren't expecting organized convective complexes,
so the severe threat is limited. However, there is potential for
some mid level dry air entrainment (according to model soundings -
generally between 600 and 500 mb), and with potential for precip
loading, can't rule out a few downbursts leading to gusty winds.
Overall though, the threat for severe winds is quite limited.
Temperatures: For most of the region (that will remain southeast of
the stalled front), we'll have similar conditions to yesterday with
highs in the upper 80s to near 90, and heat index values mostly in
the upper 90s. We should stay below heat advisory criteria across
the region. In the southern Poconos and far northwestern NJ, which
have a chance to be NW of the front when it stalls, highs will
likely be in the lower to mid 80s with heat index values near the
temperatures (there isn't much of a temperature gradient across the
front, but there should be drier air behind the front.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
Overnight, surface based instability will decrease slightly (as is
typical), but the area of synoptic scale lift associated with the
right entrance region of the upper level jet could nudge closer to
our region. At the surface though, we will loose some of the low
level convergence (i.e. sea and bay breezes should wash out).
Overall, I expect coverage of showers and storms to decrease through
the overnight hours. However, for any showers and storms that do
continue overnight, there remains some concern for heavy rain.
Temperatures will once again be a factor of where the front is
stalled by this time. Northwest of the front (likely the southern
Poconos and NW NJ), drier air will allow some radiational cooling so
lows in the lower 60s are possible. Southeast of the front, we will
likely still see some moisture pooling, so lows will likely stay in
the 70s.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Synoptic Overview...
The start of the extended will feature a a pair of H5 ridges
centered over the SW and SE US, while to the north of these features
a succession of shortwave ridges and troughs will be passing through
the Central/Northern US and Southern Canada. For our area the most
impactful shortwave is currently centered near Arkansas/Missouri.
This wave will only very slowly progress eastward over the next few
days, while a fairly amplified (but progressive) ridge develops to
its north. Although the wave itself may not reach our area until
Sunday/early next week numerous vort maxes will eject out ahead of
it into our area (the most potent likely impacting us on Thursday).
A more amplified trough will push the Canadian ridge eastward Sunday
into Monday, and this trough should ultimately absorb the
aforementioned southern shortwave. By early next week the overall
synoptic pattern over the US will then become characterized by an
amplified ridge over the western US and a longwave trough over the
eastern US, with various shortwaves pivoting SEwrd around the base
of the larger trough towards our area.
At the surface the cold front from today will only very slowly
progress southward with its thermal/moisture gradients washing
out somewhat over the first few days of the long term. Guidance
has become more bullish on developing a stronger frontal low
south of our area on Friday, and that low combined with the High
over eastern Canada will promote a somewhat drier E-NE flow
Friday into Saturday. By early next week another frontal low
will form to our south and begin to phase with a stronger low in
Canada. It is possible the boundary returns northward towards
our area in this time period and there could also be a cold
frontal passage associated with the northern low, but details
remain nebulous.
Dailies...
Thursday... The boundary will be in our general vicinity on Thursday
with PWATS > 2 inches pooled across the southern half of our
boundary, while a stronger shortwave will eject from the trough over
the southern US and pass over our area. Consequently expect another
day of scattered to numerous thunderstorm development with some
potential for renewed hydro concerns. The main limiting factor
relative to Wednesday will be instability with guidance generally
depicting peak MLCAPEs only around 1500 J/kg or so, due to cooler
temperatures and weaker lapse rates relative to Wed. That being said
the storm-layer flow will still be fairly weak (albeit a little
stronger than Wed due to the aforementioned wave), and moisture
parameters remain well above climo. Consequently despite the
likelihood of lower peak rain rates, there may still be a risk of
localized flash flooding, particularly if storms can form over areas
that received heavy rainfall today. Clouds and precipitation will
result in maxes only in the low to mid 80s.
Friday/Saturday... The current suite of guidance paints a relatively
drier picture for this period as High Pressure builds to our north,
and the boundary is pushed south. This is a somewhat different
evolution than guidance had been depicting the past couple nights so
only partially cut PoPs with this package, but it is possible they
can be decreased further if guidance continues coming in with this
drier solution. Generally expect temperatures to stay on the mild
side given the prevailing onshore flow and cloud cover, with highs
generally in the low to possibly mid 80s. Although dewpoints will
almost certainly come down relative to Wed/Thursday just how much is
still a question. Went with a blend this forecast package, however
some of the drier guidance does hint at dewpoints dropping into the
50s for the northern portion of our area on Saturday.
Sunday-Tuesday... Things will likely get more active in this period
as the High to our north moves away and we potentially feel the
influence of both a frontal low to our south and a northern branch
low passing over Canada. Given the uncertainty of how/when these
features would interact and any frontal passages went with a fairly
middle of the road approach for PoPs (generally mid-range Chc) for
Sunday and Monday. Temps should run near or just below climo through
the period. It is possible a more substantial cold front with more
notable postfrontal drying will progress through our area on Tuesday
but there is considerable spread within the guidance on this aspect.
&&
.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.
Today... Prevailing VFR. Scattered thunderstorms are likely
this afternoon, especially for the urban corridor TAF sites of
TTN, PNE, PHL, and ILG. The best chance will be through 23z.
Sub- VFR conditions are possible in any tstms, and storms will
be slow moving so impacts of up to 2 hours are possible should a
storm impact a TAF site. Prevailing winds will be S to SW at 5
to 10 kt, but becoming more SE near the coast. Winds may also be
light and variable at times, and tstms may contain locally
gusty winds. Moderate confidence overall but lower confidence on
the timing and extent of tstms.
Tonight...Mostly VFR conditions with a persistent mid level ceiling
(at or above 5000 ft AGL). The chance for showers and storms
decreases after sunset, but isolated showers and storms will be
possible through the overnight hours. Winds becoming light and
variable. Moderate confidence.
Outlook...
Thursday.... A mixture of VFR and sub-VFR conditions probable
(particularly at KPNE and south) due to periodic showers and
thunderstorms. Winds generally 5kts or less and favoring an easterly
direction. Moderate confidence on storms, high confidence on winds.
Friday and Saturday... Mostly VFR although some storms will be
possible (mostly on Friday), also can't rule out some restrictions
in lower clouds in the morning. East-northeast winds 5-10kts on
Friday, with easterly winds around 10 kts on Saturday. Moderate
confidence.
Sunday... A chance of showers of thunderstorms in the afternoon.
East-southeast winds 5-10kts. Moderate confidence.
&&
.MARINE...
Winds and seas should stay below Small Craft Advisory criteria
through tonight. However, locally higher winds and waves will be
possible in the vicinity of any showers and storms. Patchy fog is
possible through this morning.
Outlook...
Thursday...Winds and seas should stay below Small Craft
Advisory criteria. Thunderstorms are possible, which could
produce locally higher winds and waves.
Friday through Sunday...An increasing onshore flow and building seas
later Friday may require a SCA by Friday night with potential SCA
conditions continuing through Sunday. Thunderstorms are possible
(primarily on Friday), which could produce locally higher winds and
waves.
Rip Currents...
The low risk for the formation of dangerous rip currents is expected
to continue today and Thursday. Breaking waves are forecast to be
less than 2 feet with a medium period swell from the southeast.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Flash Flood Watch until 11 PM EDT this evening for PAZ060>062-
070-071-101>106.
NJ...Flash Flood Watch until 11 PM EDT this evening for NJZ007>010-
012-013-015>019-021.
DE...Flash Flood Watch until 11 PM EDT this evening for DEZ001>003.
MD...Flash Flood Watch until 11 PM EDT this evening for MDZ008-012-
015-019-020.
MARINE...None.
&&
Synopsis...Carr
Near Term...Johnson/O'Brien
Short Term...Johnson
Long Term...Carr
Aviation...Carr/Johnson/O'Brien
Marine...Carr/JohnsonHazardous Weather Outlook National Weather Service Mount Holly NJ 352 AM EDT Wed Aug 12 2020 DEZ001>003-MDZ008-012-015-019-020-NJZ007>010-012-013-015>019-021- PAZ060>062-070-071-101>106-130800- New Castle-Kent-Inland Sussex-Cecil-Kent MD-Queen Annes-Talbot- Caroline-Warren-Morris-Hunterdon-Somerset-Middlesex-Western Monmouth- Mercer-Salem-Gloucester-Camden-Northwestern Burlington-Cumberland- Berks-Lehigh-Northampton-Delaware-Philadelphia-Western Chester- Eastern Chester-Western Montgomery-Eastern Montgomery-Upper Bucks- Lower Bucks- 352 AM EDT Wed Aug 12 2020 ...FLASH FLOOD WATCH IN EFFECT FROM 11 AM EDT THIS MORNING THROUGH THIS EVENING... This Hazardous Weather Outlook is for central Delaware, northern Delaware, southern Delaware, northeast Maryland, central New Jersey, northern New Jersey, northwest New Jersey, southern New Jersey, east central Pennsylvania and southeast Pennsylvania. .DAY ONE...Today and tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Flash Flood Watch. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Thunderstorms Thursday could produce locally heavy rainfall which may lead to localized flooding .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. NJZ001-020-022-023-027-PAZ054-055-130800- Sussex-Ocean-Atlantic-Cape May-Southeastern Burlington-Carbon-Monroe- 352 AM EDT Wed Aug 12 2020 This Hazardous Weather Outlook is for northern New Jersey, southern New Jersey and northeast Pennsylvania. .DAY ONE...Today and tonight. There is a low probability for widespread hazardous weather. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. There is a low probability for widespread hazardous weather. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. DEZ004-NJZ014-024>026-130800- Delaware Beaches-Eastern Monmouth-Atlantic Coastal Cape May- Coastal Atlantic-Coastal Ocean- 352 AM EDT Wed Aug 12 2020 This Hazardous Weather Outlook is for southern Delaware, central New Jersey and southern New Jersey. .DAY ONE...Today and 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... Spotter activation is not expected at this time. ANZ430-431-450>455-130800- Delaware Bay waters north of East Point NJ to Slaughter Beach DE- Delaware Bay waters south of East Point NJ to Slaughter Beach DE- Coastal waters from Sandy Hook to Manasquan Inlet NJ out 20 nm- Coastal waters from Manasquan Inlet to Little Egg Inlet NJ out 20 nm- Coastal waters from Little Egg Inlet to Great Egg Inlet NJ out 20 nm- Coastal waters from Great Egg Inlet to Cape May NJ out 20 nm- Coastal waters from Cape May NJ to Cape Henlopen DE out 20 nm- Coastal waters from Cape Henlopen to Fenwick Island DE out 20 nm- 352 AM EDT Wed Aug 12 2020 This Hazardous Weather Outlook is for Atlantic coastal waters and Delaware Bay Waters. .DAY ONE...Today and 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... Spotter activation is not expected at this time.
PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1046 AM EDT WED AUG 12 2020
...STORM REPORTS FROM AUGUST 7...
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0502 PM TSTM WND DMG 2 NNW SADSBURYVILLE 40.00N 75.91W
08/07/2020 CHESTER PA DEPT OF HIGHWAYS
DOWN TREE IN WIRES ON OLD WILMINGTON ROAD
AND OAK STREET. TIME ESTIMATED FROM RADAR.
0503 PM TSTM WND DMG MOUNT VERNON 39.81N 76.02W
08/07/2020 CHESTER PA DEPT OF HIGHWAYS
DOWNED TREE INTO WIRES ON PA 472 NEAR
OXFORD. TIME ESTIMATED FROM RADAR.
0505 PM TSTM WND DMG COCHRANVILLE 39.89N 75.92W
08/07/2020 CHESTER PA 911 CALL CENTER
TREE BLOWN DOWN BLOCKING SOUTHBOUND LANE AT
THE INTERSECTION OF LIMESTONE RD AND GAP
NEWPORT PIKE. TIME ESTIMATED FROM RADAR.
0508 PM TSTM WND DMG 1 NE LONDONDERRY TWP 39.87N 75.88W
08/07/2020 CHESTER PA FIRE DEPT/RESCUE
SEVERAL TREES DOWN ALONG PORTIONS OF ROUTE
41. TIME ESTIMATED FROM RADAR.
0512 PM TSTM WND DMG 1 SSW EAST BRANDYWINE T 40.02N 75.77W
08/07/2020 CHESTER PA UTILITY COMPANY
SEVERAL TREES AND POLES DOWN JUST NORTH OF
FISHERVILLE ROAD. TIME ESTIMATED FROM RADAR.
0525 PM TSTM WND GST 2 E LONDONDERRY TWP 39.86N 75.84W
08/07/2020 E52 MPH CHESTER PA MESONET
52 MPH WIND GUST MEASURED AT WEST GROVE DEOS
(DSCR) MESONET.
0527 PM FLASH FLOOD PARKESBURG 39.96N 75.92W
08/07/2020 CHESTER PA LAW ENFORCEMENT
WATER RESCUE REPORTED AT MAPLE ST AND S
CULVERT ST IN PARKESBURG BOROUGH. TIME
ESTIMATED FROM DISPATCH.
0538 PM TSTM WND DMG HOCKESSIN 39.79N 75.69W
08/07/2020 NEW CASTLE DE BROADCAST MEDIA
SOME TREES DOWN IN HOCKESSIN. TIME ESTIMATED
FROM RADAR.
0540 PM TSTM WND DMG 1 SE WEST GOSHEN 39.96N 75.56W
08/07/2020 CHESTER PA DEPT OF HIGHWAYS
DOWNED TREE IN WIRES ON WESTTOWN THORNTON
ROAD AND FIVE POINTS ROAD. TIME ESTIMATED
FROM RADAR.
0540 PM TORNADO ASHLAND 39.80N 75.66W
08/07/2020 NEW CASTLE DE NWS STORM SURVEY
AN EF1 TORNADO WITH WINDS TO 105 MPH TOUCHED
DOWN IN ASHLAND AND TRACKED TO MONTCHANIN IN
NORTHERN DELAWARE. NUMEROUS TREES WERE
DOWNED, SNAPPED OR UPROOTED. A NOTED
CONVERGENT PATTERN IN THE DEBRIS WAS
OBSERVED IN THE TREE DAMAGE ACROSS THE
WILMINGTON COUNTRY CLUB.
0541 PM TSTM WND DMG 1 W GREENVILLE 39.78N 75.62W
08/07/2020 NEW CASTLE DE NWS STORM SURVEY
SIGNIFICANT STRAIGHT-LINE WIND DAMAGE
OCCURRED DUE TO A SEVERE REAR-FLANK
DOWNDRAFT WITH WINDS UP TO 95 MPH. THIS
OCCURRED FROM GREENVILLE TO WILMINGTON IN
NORTHERN DELAWARE. QUITE A BIT OF TREE
DAMAGE OCCURRED INCLUDING A TREE SNAPPED AT
ITS BASE. THE SIGNIFICANT DAMAGE ENDED NEAR
THE DELAWARE ART MUSEUM IN THE KENTMERE
SECTION OF WILMINGTON. SPORADIC DAMAGE
CONTINUED EAST TOWARD THE INTERSECTION OF
I-95 AND CONCORD PIKE WHERE UTILITY
COMPANIES HAD TO REMOVE DEBRIS FROM THE
POWER LINES AND ADDITIONAL TREES WERE
KNOCKED DOWN IN HAYNES PARK.
0545 PM FLASH FLOOD HOCKESSIN 39.79N 75.69W
08/07/2020 NEW CASTLE DE BROADCAST MEDIA
SIGNIFICANT FLOODING ACROSS LANCASTER PIKE
IN HOCKESSIN WITH AT LEAST ONE CAR STUCK IN
THE FLOOD WATERS.
0550 PM TSTM WND DMG 2 SE EAST NANTMEAL TWP 40.11N 75.69W
08/07/2020 CHESTER PA LAW ENFORCEMENT
TREE REPORTED DOWN AT BLACK HORSE RD IN WEST
VINCENT TOWNSHIP. TIME ESTIMATED FROM
DISPATCH.
0550 PM TSTM WND DMG 1 N MONTCHANIN 39.80N 75.59W
08/07/2020 NEW CASTLE DE PUBLIC
TREES AND WIRES DOWN ALONG MONTCHANIN RD
NORTH OF WILMINTON. TIME ESTIMATED BY RADAR.
0550 PM TSTM WND DMG WEST HAVEN 39.76N 75.59W
08/07/2020 NEW CASTLE DE TRAINED SPOTTER
NUMEROUS TREES DOWN OR SNAPPED WITH SOME
ONTO HOMES. TIME ESTIMATED FROM RADAR.
0550 PM TSTM WND DMG 1 NE WOODDALE 39.78N 75.62W
08/07/2020 NEW CASTLE DE PUBLIC
SEVERAL TREES DOWN ALONG CENTERVILLE ROAD IN
WESTERN GREENVILLE. TIME ESTIMATED FROM
RADAR AND NEARBY REPORTS.
0550 PM TSTM WND DMG GREENVILLE 39.78N 75.60W
08/07/2020 NEW CASTLE DE PUBLIC
TREES DOWN IN GREENVILLE. TIME ESTIMATED BY
RADAR.
0552 PM FLASH FLOOD 1 S KENNETT SQUARE 39.84N 75.71W
08/07/2020 CHESTER PA LAW ENFORCEMENT
ONE VEHICLE STUCK IN RISING WATER AT SOUTH
ST. AND HARVEY CIRCLE IN KENNETT SQUARE.
TIME ESTIMATED FROM DISPATCH.
0552 PM TSTM WND DMG GREENVILLE MANOR 39.78N 75.60W
08/07/2020 NEW CASTLE DE PUBLIC
TREES AND POWER POLES DOWN IN GREENVILLE.
TIME ESTIMATED FROM RADAR.
0555 PM TSTM WND DMG ROCK MANOR 39.77N 75.55W
08/07/2020 NEW CASTLE DE BROADCAST MEDIA
LARGE TREE UPROOTED AND BLOCKING SCHOOL ROAD
IN ALAPOCAS. TIME ESTIMATED FROM RADAR.
0555 PM TSTM WND DMG WILMINGTON 39.75N 75.55W
08/07/2020 NEW CASTLE DE BROADCAST MEDIA
TREES DOWN OR SNAPPED ON NORTH MADISON
STREET BETWEEN WEST 9TH AND WEST 10TH
STREETS IN WILMINGTON. TIME ESTIMATED FROM
RADAR.
0555 PM TSTM WND DMG PHILLIPS HEIGHTS 39.77N 75.51W
08/07/2020 NEW CASTLE DE AMATEUR RADIO
TREE DOWN ONTO POWER LINES AT WILMINGTON
WASHINGTON STREET EXTENSION AND HANOVER ROAD
IN NORTH WILMINGTON. TIME ESTIMATED FROM
RADAR.
0555 PM TSTM WND GST WINTERTHUR 39.80N 75.61W
08/07/2020 M54 MPH NEW CASTLE DE MESONET
GREENVILLE DEOS (DGRN) MEASURED A 54 MPH
WIND GUST.
0556 PM FLOOD 2 S KENNETT SQUARE 39.81N 75.71W
08/07/2020 CHESTER PA 911 CALL CENTER
STREAM WAS REPORTED BLOCKED AND CREATING A
LAKE ON THE ROADWAY AT THE INTERSECTION OF
BUCKTOE RD. AND CHANDLER MILL RD.
0557 PM TSTM WND DMG EDGEMOOR GARDENS 39.76N 75.50W
08/07/2020 NEW CASTLE DE FIRE DEPT/RESCUE
TREE ONTO A HOUSE WITH PEOPLE TRAPPED IN
EDGEMOOR GARDENS. POWER LINES DOWN. TIME
ESTIMATED FROM RADAR.
0558 PM FLASH FLOOD 1 NE TOUGHKENAMON 39.84N 75.75W
08/07/2020 CHESTER PA LAW ENFORCEMENT
ROADWAY FLOODED AT BANCROFT RD AND CRESTVIEW
DR IN NEW GARDEN TOWNSHIP. TIME ESTIMATED
FROM DISPATCH.
0603 PM FLASH FLOOD 1 ESE TRAINER 39.83N 75.39W
08/07/2020 DELAWARE PA 911 CALL CENTER
WATER RESCUE REPORTED.
0603 PM FLASH FLOOD 1 S KENNETT SQUARE 39.84N 75.71W
08/07/2020 CHESTER PA 911 CALL CENTER
WATER RESCUE AT THE INTERSECTION OF SOUTH
STREET AND HARVEY CIRCLE.
0609 PM TSTM WND DMG WINTERTHUR 39.80N 75.61W
08/07/2020 NEW CASTLE DE TRAINED SPOTTER
TREES AND WIRES DOWN AT KENNETT PIKE AND OLD
KENNETT ROAD.
0610 PM FLASH FLOOD ASTON TWP. 39.86N 75.43W
08/07/2020 DELAWARE PA LAW ENFORCEMENT
WATER RESCUE AT WEIR RD AND PENNELL RD. TIME
ESTIMATED FROM DISPATCH.
0610 PM FLASH FLOOD 1 NW ASHLAND 39.81N 75.67W
08/07/2020 NEW CASTLE DE TRAINED SPOTTER
A HOME IN YORKLYN WAS TAKING ON WATER.
0611 PM FLASH FLOOD ASTON TWP. 39.86N 75.42W
08/07/2020 DELAWARE PA LAW ENFORCEMENT
WATER RESCUE REPORTED ON RAYMOND AVENUE IN
ASHTON TOWNSHIP.
0612 PM FLASH FLOOD GREEN RIDGE 39.87N 75.41W
08/07/2020 DELAWARE PA LAW ENFORCEMENT
ROAD CLOSURE AT E DUTTON MILL RD AND CHESTER
CREEK RD. TIME ESTIMATED FROM DISPATCH.
0615 PM FLASH FLOOD UPPER CHICHESTER TWP 39.86N 75.46W
08/07/2020 DELAWARE PA PUBLIC
PICTURE SHOWS DEEP WATER CLOSING A ROAD IN
UPPER CHICHESTER TOWNSHIP. TIME ESTIMATED
FROM RADAR AND NEARBY REPORTS.
0615 PM TSTM WND DMG MEDIA 39.92N 75.39W
08/07/2020 DELAWARE PA TRAINED SPOTTER
SEVERAL TREES DOWN ACROSS THE SOUTHERN
PORTION OF DELAWARE COUNTY. TIME ESTIMATED
FROM RADAR.
0615 PM FLASH FLOOD 2 N AVONDALE 39.85N 75.79W
08/07/2020 CHESTER PA 911 CALL CENTER
WATER RESCUE AT THE INTERSECTION OF MCCUE
ROAD AND WOODVIEW ROAD.
0616 PM FLASH FLOOD 1 WNW SPRINGFIELD TWP 39.94N 75.35W
08/07/2020 DELAWARE PA LAW ENFORCEMENT
CORRECTS PREVIOUS FLASH FLOOD REPORT FROM 1
WNW SPRINGFIELD TWP. WATER RESCUE REPORTED
ON OLD MARPLE RD MARPLE TOWNSHIP. TIME
ESTIMATED FROM DISPATCH.
0617 PM FLASH FLOOD ASTON TWP. 39.87N 75.43W
08/07/2020 DELAWARE PA LAW ENFORCEMENT
WATER RESCUE REPORTED AT CONCORD RD IN
ASHTON TOWNSHIP.
0621 PM FLASH FLOOD 3 S KENNETT SQUARE 39.80N 75.71W
08/07/2020 CHESTER PA LAW ENFORCEMENT
CREEK FLOODING AT KAOLIN RD AND CALDWELL LN.
ROAD CLOSED. TIMES ESTIMATED FROM DISPATCH.
0625 PM FLASH FLOOD 1 ESE LANDENBERG 39.77N 75.74W
08/07/2020 CHESTER PA LAW ENFORCEMENT
CORRECTS PREVIOUS FLASH FLOOD REPORT FROM 1
ESE LANDENBERG. BROAD RUN RD AT NEWARK RD
ROAD CLOSED DUE TO HIGH WATER. TIME
ESTIMATED FROM DISPATCH.
0626 PM FLASH FLOOD 1 ENE CONCORDVILLE 39.89N 75.51W
08/07/2020 DELAWARE PA LAW ENFORCEMENT
WATER RESCUE AT BALTIMORE PIKE AND CHEYNEY
RD. TIME ESTIMATED FROM DISPATCH.
0630 PM FLASH FLOOD 1 SSW KENNETT SQUARE 39.83N 75.72W
08/07/2020 CHESTER PA LAW ENFORCEMENT
WATER RESCUE AT W HILLENDALE RD AND CHANDLER
MILL RD. TIME BASED OFF OF DISPATCH.
0640 PM HEAVY RAIN ASTON TWP. 39.87N 75.43W
08/07/2020 M3.51 INCH DELAWARE PA PUBLIC
3.51 INCHES OF RAIN IN 50 MINUTES ENDING AT
6:40 PM.
0640 PM FLASH FLOOD 1 SSW BOOTHWYN 39.82N 75.45W
08/07/2020 DELAWARE PA PUBLIC
PICTURE ON SOCIAL MEDIA SHOWS FLOODING AT A
LOCAL BUSINESS NEAR THE WEST BRANCH NAAMAN
CREEK. TIME ESTIMATED FROM RADAR AND NEARBY
REPORTS.
0650 PM TSTM WND DMG YARDLEY 40.24N 74.84W
08/07/2020 BUCKS PA 911 CALL CENTER
SEVERAL TREES AND WIRES REPORTED DOWN IN THE
AREA OF YARDLEY AND WOODSIDE. TIME ESTIMATED
FROM RADAR.
0650 PM TSTM WND DMG WOODSTOWN 39.66N 75.33W
08/07/2020 SALEM NJ PUBLIC
SOME TREES DOWN IN THE WOODSTOWN AREA. TIME
ESTIMATED FROM RADAR.
0655 PM FLOOD 2 E PILESGROVE TWP 39.67N 75.36W
08/07/2020 SALEM NJ TRAINED SPOTTER
FLOODING ON KINGS HIGHWAY.
0700 PM FLASH FLOOD MIDDLETOWN TWP. 39.92N 75.42W
08/07/2020 DELAWARE PA TRAINED SPOTTER
ROUTE 1 CLOSED IN SEVERAL LOCATIONS DUE TO
FLOODING.
0700 PM TSTM WND DMG 2 SW GLENDORA 39.82N 75.09W
08/07/2020 GLOUCESTER NJ DEPT OF HIGHWAYS
DOWNED TREE, POLE AND WIRES ON NJ 41 BOTH
DIRECTIONS NORTH OF GOOD INTENT ROAD IN
DEPTFORD TOWNSHIP. ALL LANES CLOSED. TIME
ESTIMATED FROM RADAR.
0700 PM FLASH FLOOD LOGAN TWP. 39.80N 75.35W
08/07/2020 GLOUCESTER NJ PUBLIC
CARS STUCK IN FLOODED WATER, KNEE HIGH DEEP
WATER IN SOME AREAS. TIME ESTIMATED RADAR.
0705 PM TSTM WND GST 2 NNE SEABROOK FARMS 39.53N 75.20W
08/07/2020 M89 MPH CUMBERLAND NJ MESONET
RUTGERS AGRICULTURAL RESEARCH AND EXTENSION
CENTER AT UPPER DEERFIELD, NJ.
0715 PM FLASH FLOOD WOOLWICH TWP 39.76N 75.31W
08/07/2020 GLOUCESTER NJ TRAINED SPOTTER
WIDESPREAD FLASH FLOODING OF ROADS AND
PROPERTIES REPORTED IN SWEDESBORO.
0717 PM TSTM WND GST 4 NNW SEABROOK FARMS 39.55N 75.24W
08/07/2020 M69 MPH CUMBERLAND NJ TRAINED SPOTTER
69 MPH THUNDERSTORM WIND GUST MEASURED ON
ROUTE 77 AT MILE MARKER 9.
0720 PM FLASH FLOOD 3 N PILESGROVE TWP 39.71N 75.38W
08/07/2020 SALEM NJ DEPT OF HIGHWAYS
FLOODING ACROSS THE NEW JERSEY TURNPIKE BOTH
DIRECTIONS BETWEEN THE DELAWARE MEMORIAL
BRIDGE AND US 322. ALL LANES ARE BLOCKED.
0721 PM TSTM WND DMG STILL POND 39.33N 76.04W
08/07/2020 KENT MD DEPT OF HIGHWAYS
DELAYED REPORT. WIND-BLOWN DEBRIS CLOSED
STATE HIGHWAY 292 NEAR STATE HIGHWAY 566.
TIME ESTIMATED FROM RADAR.
0728 PM TSTM WND DMG 3 SSE KENTON 39.19N 75.65W
08/07/2020 KENT DE UTILITY COMPANY
DELAYED REPORT. DOWNED TREE AND WIRES NEAR
SHAWS CORNER ROAD SOUTHEAST OF KENTON. TIME
ESTIMATED FROM RADAR.
0728 PM TSTM WND DMG 2 SE WOODLAND BEACH 39.31N 75.44W
08/07/2020 KENT DE UTILITY COMPANY
DELAYED REPORT. DOWNED TREE AND WIRES NEAR
WOODLAND BEACH. TIME ESTIMATED FROM RADAR.
0744 PM TSTM WND DMG TEMPLEVILLE 39.14N 75.77W
08/07/2020 QUEEN ANNES MD DEPT OF HIGHWAYS
DELAYED REPORT. WIND-BLOWN DEBRIS CLOSED
STATE HIGHWAY 302 NEAR BEAR POND ROAD. TIME
ESTIMATED FROM RADAR.
0745 PM TSTM WND DMG 1 NW MINOTOLA 39.53N 74.96W
08/07/2020 ATLANTIC NJ PUBLIC
TELEPHONE PONES SNAPPED IN HALF WITH WIRES
DOWN ON BREWSTER AND FOREST GROVE ROADS.
TIME ESTIMATED BY RADAR.
0745 PM FLASH FLOOD SUDLERSVILLE 39.19N 75.86W
08/07/2020 QUEEN ANNES MD DEPT OF HIGHWAYS
MD 313 CLOSED AT CHARLES STREET DUE TO HIGH
WATER.
0800 PM FLOOD NEWFIELD 39.55N 75.02W
08/07/2020 GLOUCESTER NJ PUBLIC
SOCIAL MEDIA VIDEO SHOWS SEVERE BACKYARD
FLOODING. TIME ESTIMATED FROM RADAR.
0828 PM FLASH FLOOD 1 NW BUENA 39.53N 74.95W
08/07/2020 ATLANTIC NJ DEPT OF HIGHWAYS
DELAYED REPORT. FLASH FLOODING CLOSED U.S.
HIGHWAY 40 BETWEEN MALAGA ROAD AND EAST
SUMMER ROAD IN BUENA. TIME BASED ON DISPATCH
REPORT.
0835 PM FLASH FLOOD 1 NW VINELAND 39.50N 75.04W
08/07/2020 CUMBERLAND NJ DEPT OF HIGHWAYS
DELAYED REPORT. FLASH FLOODING CLOSED STATE
HIGHWAY 47 IN AREA OF OAK ROAD IN VINELAND.
TIME BASED ON DISPATCH REPORT.
0846 PM FLASH FLOOD 2 SW MILLINGTON 39.24N 75.87W
08/07/2020 QUEEN ANNES MD DEPT OF HIGHWAYS
DELAYED REPORT. FLASH FLOODING CLOSED STATE
HIGHWAY 313 NEAR STATE HIGHWAY 544. TIME
BASED ON DISPATCH REPORT.
0850 PM TSTM WND DMG 1 ENE SEAVILLE 39.22N 74.68W
08/07/2020 CAPE MAY NJ TRAINED SPOTTER
CORRECTS PREVIOUS TSTM WND DMG REPORT FROM 1
ENE SEAVILLE. TREE DOWN ON GARDEN STATE
PARKWAY NEAR MILE MARKER 21.9. TIME
ESTIMATED BY RADAR.
0850 PM HEAVY RAIN VILLAS 39.03N 74.94W
08/07/2020 M1.00 INCH CAPE MAY NJ TRAINED SPOTTER
1 INCH OF RAIN IN JUST 10 MINUTES IN THE
VILLAS MIAMI BEACH SECTION.
0850 PM HEAVY RAIN DENNISVILLE 39.20N 74.82W
08/07/2020 M1.10 INCH CAPE MAY NJ TRAINED SPOTTER
1.10 INCHES OF RAIN IN JUST 9 MINUTES.
0854 PM MARINE TSTM WIND LUDLAM BAY 39.18N 74.70W
08/07/2020 E47 MPH ANZ453 NJ PUBLIC
41 KNOTS AT LUDLAM BAY.
0907 PM FLASH FLOOD SUDLERSVILLE 39.19N 75.86W
08/07/2020 QUEEN ANNES MD DEPT OF HIGHWAYS
DELAYED REPORT. FLASH FLOODING CLOSED STATE
HIGHWAY 300 AT STATE HIGHWAY 837. TIME BASED
ON DISPATCH REPORT.
0938 PM FLASH FLOOD 1 N NORTH WILDWOOD 39.01N 74.80W
08/07/2020 CAPE MAY NJ DEPT OF HIGHWAYS
DELAYED REPORT. FLASH FLOODING CLOSED STATE
HIGHWAY 147 NEAR MARYLAND AVENUE IN NORTH
WILDWOOD. TIME BASED ON DISPATCH REPORT.
0940 PM FLASH FLOOD 2 NW CARDIFF 39.43N 74.61W
08/07/2020 ATLANTIC NJ DEPT OF HIGHWAYS
DELAYED REPORT. FLASH FLOODING CLOSED U.S.
HIGHWAY 40 NEAR ENGLISH CREEK AVENUE. TIME
BASED ON DISPATCH REPORT.
0945 PM FLASH FLOOD ELKTON 39.61N 75.82W
08/07/2020 CECIL MD PUBLIC
WATER RESCUE ON DELAWARE AVE NEAR MEADOW
PARK. ROAD WAS CLOSED DUE TO FLOODING. TIME
ESTIMATED FROM RADAR.
1003 PM FLASH FLOOD 1 S POMONA 39.46N 74.54W
08/07/2020 ATLANTIC NJ DEPT OF HIGHWAYS
DELAYED REPORT. FLASH FLOODING CLOSED U.S.
HIGHWAY 30 NEAR GARDEN STATE PARKWAY. TIME
BASED ON DISPATCH REPORT.
&&
CMS/MJG/LR/MPS/BAH/SFJ/DISpecial Weather Statement
National Weather Service Mount Holly NJ
1148 AM EDT Wed Aug 12 2020
NJZ018-019-PAZ071-104-121615-
Northwestern Burlington-Camden-Eastern Montgomery-Philadelphia-
1148 AM EDT Wed Aug 12 2020
...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN CAMDEN...WEST
CENTRAL BURLINGTON...SOUTHEASTERN MONTGOMERY AND PHILADELPHIA
COUNTIES...
At 1147 AM EDT, a strong thunderstorm was located over Philadelphia.
The storm is nearly stationary.
Wind gusts up to 50 mph are possible with this storm.
Locations impacted include...
Philadelphia, Camden, Palmyra, Jenkintown, Narberth, Rockledge, Bryn
Athyn, Wissinoming, Germantown, Northeast Philadelphia, Center City,
Tacony, Ben Franklin Bridge, Andalusia, Holmesburg, Kensington,
Roxborough, Chestnut Hill, Cherry Hill Mall and Golden Triangle.
This includes the following highways...
Interstate 95 in Pennsylvania between mile markers 19 and 33.
Interstate 76 in Pennsylvania between mile markers 334 and 350.
Interstate 676 in Pennsylvania between mile markers 0 and 1.
Interstate 676 in New Jersey between mile markers 2 and 4.
This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
LAT...LON 3990 7518 4006 7531 4014 7501 4012 7497
4007 7497 4006 7498 4005 7496 3996 7495
TIME...MOT...LOC 1547Z 161DEG 2KT 4000 7510
CMSSpecial Weather Statement National Weather Service Mount Holly NJ 1206 PM EDT Wed Aug 12 2020 NJZ013-014-020-026-121630- Eastern Monmouth-Coastal Ocean-Ocean-Western Monmouth- 1206 PM EDT Wed Aug 12 2020 ...A STRONG THUNDERSTORM WILL AFFECT NORTHERN OCEAN AND SOUTHEASTERN MONMOUTH COUNTIES... At 1206 PM EDT, a strong thunderstorm was located over Lakewood, or 9 miles north of Toms River, moving east at 10 mph. Wind gusts up to 50 mph are possible with this storm. Locations impacted include... Toms River, Asbury Park, Lakewood, Jackson, Howell, Tinton Falls, Manasquan, Point Pleasant Beach, Lakehurst, Farmingdale, Mantoloking, Leisure Village, Allenwood, Dover Beaches North, Pleasant Plains, Cedar Glen West, Jacksons Mills, Leisure Village East, Cassville and Vista Center. This includes the following highways... Interstate 195 in New Jersey between mile markers 22 and 34. Garden State Parkway between mile markers 84 and 102. This storm may intensify, so be certain to monitor local radio stations and available television stations for additional information and possible warnings from the National Weather Service. LAT...LON 4001 7450 4021 7428 4025 7397 3997 7402 TIME...MOT...LOC 1606Z 270DEG 9KT 4012 7419 CMS
Special Weather Statement
National Weather Service Mount Holly NJ
1216 PM EDT Wed Aug 12 2020
NJZ019-PAZ106-121645-
Northwestern Burlington-Lower Bucks-
1216 PM EDT Wed Aug 12 2020
...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN BURLINGTON AND
SOUTHEASTERN BUCKS COUNTIES...
At 1216 PM EDT, a strong thunderstorm was located over Jacksonville,
or 11 miles south of Trenton, moving east at 5 mph.
Wind gusts up to 50 mph are possible with this storm.
Locations impacted include...
Willingboro, Lumberton, Florence, Burlington, Bristol, Mount Holly,
Riverside, Bordentown, Beverly, Tullytown, Florence-Roebling,
Jobstown, Columbus, Jacksonville, Georgetown, Levittown, Cinnaminson,
Edgewater Park, Delanco and Fieldsboro.
This includes the following highways...
New Jersey Turnpike between exits 5 and 7A.
Pennsylvania Turnpike between mile markers 356 and 359.
Interstate 95 in Pennsylvania between mile markers 37 and 40.
Interstate 295 in New Jersey between mile markers 41 and 57.
Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.
This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
LAT...LON 3992 7472 3998 7501 3998 7502 4014 7488
4015 7463 4014 7462
TIME...MOT...LOC 1616Z 274DEG 5KT 4005 7480
CMSSpecial Weather Statement National Weather Service Mount Holly NJ 1255 PM EDT Wed Aug 12 2020 DEZ001-002-121730- Kent-New Castle- 1255 PM EDT Wed Aug 12 2020 ...A STRONG THUNDERSTORM WILL AFFECT SOUTH CENTRAL NEW CASTLE AND NORTHERN KENT COUNTIES... At 1254 PM EDT, a strong thunderstorm was located over Smyrna, or 10 miles north of Dover. The storm is nearly stationary. Wind gusts up to 45 mph are possible with this storm. Locations impacted include... Smyrna, Clayton, Woodland Beach, Green Spring, Kenton, Leipsic and Chambersville. Torrential rainfall is also occurring with this storm, and may cause localized flooding. Do not drive your vehicle through flooded roadways. Frequent cloud to ground lightning is occurring with this storm. Lightning can strike 10 miles away from a thunderstorm. Seek a safe shelter inside a building or vehicle. LAT...LON 3922 7566 3930 7574 3941 7553 3924 7540 TIME...MOT...LOC 1654Z 202DEG 0KT 3931 7558 Staarmann
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
239 PM EDT WED AUG 12 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0230 PM HEAVY RAIN MANSFIELD TWP 40.79N 74.92W
08/12/2020 M1.80 INCH WARREN NJ TRAINED SPOTTER
LOST POWER.
&&
TCDThe Philadelphia radar (KDIX), 116 km away, was scanning. The volume nearest the first event began at 18:43 UTC.
3 flash flood. Local standard time, as filed.
A water rescue took place on Lincoln Avenue at Bailey Road in Caln Township. Another water rescue took place on Park Drive at G.O. Carlson Boulevard in Caln Township.
A water rescue took place on the Industrial Highway in Tinicum Township.
Several roads in Lower Oxford Township were impassable due to flooding.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2020Every state in 2020This day in weather historyWarnings in Pennsylvania, August 2020
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: 902119, 902122, 902130.