Special Weather Statement, NWS Philadelphia/Mount Holly

Area Forecast Discussion
National Weather Service Mount Holly NJ
405 PM EDT Fri Jul 14 2017

.SYNOPSIS...
A cold front will move through the region late tonight into
Saturday morning. This front will stall off the Carolina coast
through this remainder of the weekend while high pressure builds
in from the Midwest. An area of low pressure develops along the
stalled boundary and starts to move northward into our area
late Monday and Tuesday. High pressure will build into the
region for Wednesday. Another cold front will slowly drop down
from the north on Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
A 1012 mb surface low was analyzed near the eastern shore of
Lake Ontario in central NY. The frontal structure of this system
included a cold front that extended southwestward from the low
across the Ohio Valley a warm front that extended to the south
into central PA and curved to the east across near the PA-DE
border and adjacent southern NJ.

The focus for the active weather has shifted farther south than
yesterday by only about 50 miles, which includes far SE PA, S NJ and
Delmarva. The main concerns through this evening will be locally
heavy rainfall/flash flooding and severe thunderstorms although the
the heat will also be an issue in mid Delmarva until storms arrive
late in the day.

Severe Thunderstorm Watch #414 is in effect for SE PA, including
Philadelphia, as well as S NJ, E MD and DE through 9 PM. A line
of strong storms are already starting to organize near the
differential heating boundary/stationary front in southern PA.
Strong heating south of the front has resulted in a moderately
unstable airmass with MLCAPE ranging from around 1000 J/kg in
far SE PA and adjacent S NJ to 2000+ J/kg over the mid Delmarva,
per SPC mesoanalysis. It is these areas along and south of the
warm front that will be conducive for severe thunderstorms.
Expect to see pockets of damaging winds within the line segments
that move across the Watch area. Similar to yesterday, there may
be a brief spin up with storms that track along the stationary
front, where winds are backed out of the SE and E.

A Flash Flood Watch for portions of SE PA, S NJ, NE MD and DE
through midnight. These locations will be closest the frontal
boundary, where the focus for convection will be later this
afternoon and evening. An increasingly stable boundary layer
farther north into NE PA and N NJ will have a tough time
supporting deeper convective updrafts needed for heavy rainfall
rates and flash flooding. Poor drainage flooding is still a
possibility though.

A Heat Advisory is in effect for central and southern DE and
adjacent eastern Maryland. Temperatures are close to forecast
but dewpoints are several degrees higher (mid to upper 70s vs
forecast in the low to mid 70s). Observed heat indices are in
the 100-105F range as of 2 PM this afternoon.

Expect storm intensity to gradually diminish toward sunset this
evening. However, like yesterday, expect at least scattered
showers and storms to continue after dark, particularly where
the residual unstable airmass has not been worked over from
prior convection. Widely scattered leftover showers and isolated
thunderstorms were advertised along and east of I-95 for the
overnight.

Additional convection may reach NE PA and NW NJ close to
midnight. This is in association with a line of showers and
storms that has developed along the cold front in central NY
this afternoon. Hi-res CAM guidance are in general agreement
with these showers and storms weakening after dark and
eventually dissipating overnight before it the Fall Line.

Otherwise, low clouds will persist through much of the night
across eastern PA and much of NJ as a result of continued
onshore flow to the north of the front. Any breaks in the cloud
cover that occur where it has rained this afternoon could lead
to the development of fog tonight. Fog is currently expected to
be patchy in coverage.

Forecast low temperatures are in the middle 60s across NE PA and
NW NJ and lower 70s from Philadelphia southward.

&&

.SHORT TERM /SATURDAY/...
The frontal boundary that has been linger over the area for the
past few days will finally move off the coast on Saturday as
high pressure builds in from the Midwest. W-NW winds behind the
front will advect drier air into the region. This should result
in low clouds gradually clearing from west to east during the
day.

A delayed arrival of the drier air as well as the passage of a
mid-level shortwave trough could allow for isolated showers to
develop during the morning and possible early afternoon in the
coastal plain of S NJ and Delmarva.

Forecast high temperatures are in the 70s in the southern
Poconos and mid to upper 80s across the rest of the area.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Saturday night and Sunday...The cold front drops stalls off the
Carolina coast, where it remains through the rest of the
weekend. Weak high pressure will build into our area for the
weekend, keeping us dry for at least a couple of days. Might be
a bit cloudy to start the weekend off but overall skies will
become mostly to partly sunny across the region. With drier air
in place, it should feel pretty comfortable outside even with
highs reaching into the mid to upper 80s.

Monday through Tuesday...A low pressure system will develop
along the stalled boundary to our south and will start to move
northward on Monday. The models continue to show the low moving
up through Virginia on Monday and then into Delmarva and through
southern New Jersey on Tuesday. The low then pushes to the
north and east of our area late Tuesday into Wednesday. A chance
for showers and thunderstorms will exist as the surface low
makes its way into our area. A surface trough also develops
across our area again and this would provide a good source of
lift, promoting convective activity. In addition, an upper level
trough will build across the Mid- Atlantic. This will help to
deepen the southerly flow into our region as the atmosphere
becomes more unstable. Best timing for convection, at this
juncture, looks to be mainly during the afternoon and evening
hours.

Wednesday through Thursday...High pressure will build in behind
the departing low with clearing expected for Wednesday. The
upper trough slides to the east during this time. A cold front
will start to drop down from the north on Thursday. As the high
builds in, we will see a return to more of a west to southwest
flow, ushering in some warmer, and moister, air to the region.
Highs will start to creep back up and into the upper 80s to
lower 90s by Wednesday and then into the l ow to mid 90s for
Thursday. Increasing moisture will also mean increased humidity
across the area. Seems reasonable that some showers and
thunderstorms may develop during the afternoon and evening on
both days but location of activity is too difficult to pinpoint
this far out.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

IFR conditions with low clouds have held strong at PHL, PNE and
TTN with these terminals situated north of a stationary front.
Breaks in the clouds farther south have resulted in the
development of strong thunderstorms. Based on 1930Z radar, these
storms have a direct path through ILG-MIV-ACY over the next few
hours. Torrential downpours and strong winds with these storms
could bring a period of near zero visibility and peak wind
gusts of 30-50 kt.

It is expected that the low clouds and IFR CIGs will linger
into tonight from PHL northward. It is less clear if these low
clouds makes it into ILG, MIV or ACY as they should be situated
on the southern edge of the stratus deck near the stationary
front. Even if the stratus doesn't make it that far south, fog
could contribute to flight restrictions, especially overnight.

CIGs should lift during the mid to late morning on Saturday as
the front moves off the coast. There is still uncertainty
regarding how quickly they improve but latest thinking is
improvement to VFR occurs from west to east between 14Z and 18Z.

Winds 5-10 kt will vary from NE across the northern terminals to
SE across the southern terminals through sunset. An easterly
component to the winds is favored for tonight but they could
become light and variable in spots. Winds then shift out of the
west and northwest between 7 and 12 kt on Saturday in wake of a
cold fropa.

OUTLOOK...

Sunday...VFR conditions expected. Light northwest winds early,
becoming south to southeast around 10 knots or less.

Monday through Wednesday...Mainly VFR conditions expected.
Afternoon showers and thunderstorms with MVFR or lower
conditions possible. South to southeast winds around 10 knots.

&&

.MARINE...
A stalled frontal boundary is forecast will remain near the DE
Bay and adjacent coastal waters through tonight before a cold
front moves in from the NW on Saturday.

Anybody on the coastal Atlantic waters south of Little Egg
Inlet and in the Delaware Bay is strongly encouraged to pay
close attention to Special Marine Warnings that are issued.
These storms contain strong winds, hail and dangerous lightning,
which could threaten boaters that do not take shelter. Storms
should generally weaken after dark but the threat for at least
isolated storms will linger into the night.

Easterly winds 5-10 kt with gusts to 15 kt has allowed seas to
build to 3-4 ft with a few buoys approaching 5 ft. Winds should
back slightly out of the E-SE late tonight but remain at these
speeds.

A wind shift from the west will occur behind a cold front on
Saturday morning. Winds and seas will remain below SCA criteria.

OUTLOOK...
Saturday night through Wednesday...Sub-Small Craft Advisory
conditions are expected on the area waters. Locally strong
winds may accompany thunderstorms Monday through Wednesday,
especially during the afternoon and evening hours.

RIP CURRENTS...
There risk for the development of dangerous rip currents were
increased to moderate for this afternoon at the NJ shore, where
an onshore flow has lead to an increase in surf to 3 to 4 ft.
The risk is low for Delaware this afternoon.

A low risk is anticipated for Saturday along the NJ and DE
coasts.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Flash Flood Watch until midnight EDT tonight for PAZ060-070-
     071-101>104.
NJ...Flash Flood Watch until midnight EDT tonight for NJZ016>018-
     021>025.
DE...Flash Flood Watch until midnight EDT tonight for DEZ001-002.
     Heat Advisory until 8 PM EDT this evening for DEZ002-003.
MD...Flash Flood Watch until midnight EDT tonight for MDZ008-012-
     015.
     Heat Advisory until 8 PM EDT this evening for MDZ012-015-019-
     020.
MARINE...None.

&&

Synopsis...Meola/Klein
Near Term...Klein
Short Term...Klein
Long Term...Meola/Klein
Aviation...Klein/Meola
Marine...Klein/Meola

Hazardous Weather Outlook
National Weather Service Mount Holly NJ
310 PM EDT Fri Jul 14 2017

PAZ060-103-104-151915-
Berks-Western Montgomery-Eastern Montgomery-
310 PM EDT Fri Jul 14 2017

...FLASH FLOOD WATCH IN EFFECT UNTIL MIDNIGHT EDT TONIGHT...

This Hazardous Weather Outlook is for east central Pennsylvania and
southeast Pennsylvania.

.DAY ONE...This Afternoon 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...Saturday through Thursday.

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.

NJZ001-007>010-012-013-015-PAZ054-055-061-062-105-106-151915-
Sussex-Warren-Morris-Hunterdon-Somerset-Middlesex-Western Monmouth-
Mercer-Carbon-Monroe-Lehigh-Northampton-Upper Bucks-Lower Bucks-
310 PM EDT Fri Jul 14 2017

This Hazardous Weather Outlook is for central New Jersey, northern
New Jersey, northwest New Jersey, east central Pennsylvania,
northeast Pennsylvania and southeast Pennsylvania.

.DAY ONE...This Afternoon and Tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected.

DEZ002-MDZ012-015-151915-
Kent-Kent MD-Queen Annes-
310 PM EDT Fri Jul 14 2017

...HEAT ADVISORY IN EFFECT UNTIL 8 PM EDT THIS EVENING...
...FLASH FLOOD WATCH IN EFFECT UNTIL MIDNIGHT EDT TONIGHT...
...SEVERE THUNDERSTORM WATCH 414 IN EFFECT UNTIL 9 PM EDT THIS
EVENING...

This Hazardous Weather Outlook is for central Delaware and
northeast Maryland.

.DAY ONE...This Afternoon and 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.
   Flash Flood Watch.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected.

DEZ001-MDZ008-NJZ016>018-021>023-PAZ070-071-101-102-151915-
New Castle-Cecil-Salem-Gloucester-Camden-Cumberland-Atlantic-
Cape May-Delaware-Philadelphia-Western Chester-Eastern Chester-
310 PM EDT Fri Jul 14 2017

...FLASH FLOOD WATCH IN EFFECT UNTIL MIDNIGHT EDT TONIGHT...
...SEVERE THUNDERSTORM WATCH 414 IN EFFECT UNTIL 9 PM EDT THIS
EVENING...

This Hazardous Weather Outlook is for northern Delaware, northeast
Maryland, southern New Jersey and southeast Pennsylvania.

.DAY ONE...This Afternoon 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.
   Severe Thunderstorm Watch.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

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.

DEZ003-MDZ019-020-151915-
Inland Sussex-Talbot-Caroline-
310 PM EDT Fri Jul 14 2017

...HEAT ADVISORY IN EFFECT UNTIL 8 PM EDT THIS EVENING...
...SEVERE THUNDERSTORM WATCH 414 IN EFFECT UNTIL 9 PM EDT THIS
EVENING...

This Hazardous Weather Outlook is for southern Delaware and
northeast Maryland.

.DAY ONE...This Afternoon and 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...Saturday through Thursday.

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.

DEZ004-NJZ019-020-027-151915-
Delaware Beaches-Northwestern Burlington-Ocean-
Southeastern Burlington-
310 PM EDT Fri Jul 14 2017

...SEVERE THUNDERSTORM WATCH 414 IN EFFECT UNTIL 9 PM EDT THIS
EVENING...

This Hazardous Weather Outlook is for southern Delaware and
southern New Jersey.

.DAY ONE...This Afternoon and 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...Saturday through Thursday.

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.

NJZ014-151915-
Eastern Monmouth-
310 PM EDT Fri Jul 14 2017

This Hazardous Weather Outlook is for central New Jersey.

.DAY ONE...This Afternoon and Tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter Activation is not expected.

NJZ026-151915-
Coastal Ocean-
310 PM EDT Fri Jul 14 2017

...SEVERE THUNDERSTORM WATCH 414 IN EFFECT UNTIL 9 PM EDT THIS
EVENING...

This Hazardous Weather Outlook is for southern New Jersey.

.DAY ONE...This Afternoon and 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.

There is a moderate risk of rip currents through this evening.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

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.

NJZ024-025-151915-
Atlantic Coastal Cape May-Coastal Atlantic-
310 PM EDT Fri Jul 14 2017

...FLASH FLOOD WATCH IN EFFECT UNTIL MIDNIGHT EDT TONIGHT...
...SEVERE THUNDERSTORM WATCH 414 IN EFFECT UNTIL 9 PM EDT THIS
EVENING...

This Hazardous Weather Outlook is for southern New Jersey.

.DAY ONE...This Afternoon 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.
   Severe Thunderstorm Watch.

There is a moderate risk of rip currents through this evening.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

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.

ANZ430-431-452>455-151915-
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 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-
310 PM EDT Fri Jul 14 2017

...SEVERE THUNDERSTORM WATCH 414 IN EFFECT UNTIL 9 PM EDT THIS
EVENING...

This Hazardous Weather Outlook is for Atlantic coastal waters and
Delaware Bay Waters.

.DAY ONE...This Afternoon and 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...Saturday through Thursday.

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.

ANZ450-451-151915-
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-
310 PM EDT Fri Jul 14 2017

This Hazardous Weather Outlook is for Atlantic coastal waters.

.DAY ONE...This Afternoon and Tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected.

PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
458 PM EDT FRI JUL 14 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0424 PM     TSTM WND GST     TOLCHESTER              39.22N  76.24W
07/14/2017  M53 MPH          KENT               MD   MESONET

&&

CORRECTED EVENT TIME

EVENT NUMBER PHI1700996

GAINES

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
514 PM EDT FRI JUL 14 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0419 PM     TSTM WND GST     EGG HARBOR TWP          39.36N  74.64W
07/14/2017  E50 MPH          ATLANTIC           NJ   SOCIAL MEDIA

&&

EVENT NUMBER PHI1700998

GAINES

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
520 PM EDT FRI JUL 14 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0400 PM     TSTM WND DMG     1 N WOODS MILLS         39.63N  75.26W
07/14/2017                   SALEM              NJ   DEPT OF HIGHWAYS

            DOWNED TREE AND WIRES BLOCKING US 40. TIME ESTIMATED
            FROM RADAR.

&&

EVENT NUMBER PHI1700999

SFJ

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
523 PM EDT FRI JUL 14 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0419 PM     HAIL             EGG HARBOR TWP          39.36N  74.64W
07/14/2017  E0.75 INCH       ATLANTIC           NJ   SOCIAL MEDIA

&&

EVENT NUMBER PHI1701001

SFJ

Special Weather Statement
National Weather Service Mount Holly NJ
524 PM EDT FRI JUL 14 2017

DEZ002>004-142200-
Inland Sussex-Kent-Delaware Beaches-
524 PM EDT FRI JUL 14 2017

...AN OUTFLOW BOUNDARY WILL AFFECT NORTHERN SUSSEX AND SOUTHEASTERN
KENT COUNTIES...

At 524 PM EDT, radar indicated an outflow boundary was located along
a line extending from 6 miles west of North Cape May to 8 miles
southeast of Big Stone Beach to near Harrington. Movement was south
at 25 mph.

Winds up to 40 mph are possible with this outflow boundary.

Locations impacted include...
Georgetown, Milford, Seaford, Harrington, Lewes, Milton, Bridgeville,
Ellendale, Cape Henlopen State Park, Big Stone Beach, Felton,
Greenwood, Frederica, Houston, Farmington and Riverview.

LAT...LON 3864 7560 3902 7559 3903 7535 3898 7531
      3895 7532 3894 7531 3893 7532 3880 7518
      3878 7513 3880 7509 3874 7508
TIME...MOT...LOC 2124Z 341DEG 24KT 3896 7507 3891 7521 3889 7553

Robertson

Special Weather Statement
National Weather Service Mount Holly NJ
527 PM EDT FRI JUL 14 2017

DEZ002-MDZ012-015-019-020-142230-
Kent-Queen Anne's-Talbot-Kent-Caroline-
527 PM EDT FRI JUL 14 2017

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT WEST CENTRAL KENT...
NORTHERN TALBOT...QUEEN ANNE'S...NORTHERN CAROLINE AND SOUTHWESTERN
KENT COUNTIES...

At 527 PM EDT, radar indicated strong thunderstorms were located
along a line extending from near Church Hill to near Stevensville to
near Marlton. Movement was southeast at 20 mph.

Winds up to 40 mph are possible with these storms.

Locations impacted include...
Centerville, Talbot, Centreville, Greensboro, Oakland, Ridgely, St.
Michaels, Goldsboro, Queen Anne, Grasonville, Starr, Copperville,
Jumptown, Sandtown, Tilghman Island, Stevensville, Skipton, Chester,
Starkey Corner and Wye Mills.

Torrential rainfall is also occurring with these storms, 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 3886 7626 3886 7625 3879 7620 3880 7619
      3894 7621 3889 7629 3896 7631 3885 7637
      3884 7637 3885 7638 3894 7636 3897 7635
      3904 7631 3900 7617 3909 7623 3915 7590
      3900 7554 3875 7630 3868 7634 3876 7638
TIME...MOT...LOC 2127Z 298DEG 16KT 3910 7592 3902 7637 3876 7673

rOBERTSON