Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 222237

Area Forecast Discussion
National Weather Service Mount Holly NJ
637 PM EDT FRI JUL 22 2016

A weak front is expected to move into the area late tonight into
Saturday. High pressure will then build in for Sunday through
Tuesday, however another weak front arrives late Monday into Tuesday
before stalling nearby Wednesday and Thursday.


A surface trough remains across the area. While there is
instability, the water vapor imagery and some LAPS soundings clearly
show rather dry air in the mid levels (especially for the northern
half of the forecast area). This in combination with much of our
area being south of a mid level speed max is keeping the shear on
the lower side. There is some convection in southeastern New York
into portions of northeastern Pennsylvania, however it looks like
anything that can develop or move southeastward is mostly isolated
and across the far northern zones. The visible satellite imagery
also shows some cumulus, some of which were showing signs of more
vertical growth earlier, but overall it has mostly struggled. The
mid level wind max is forecast to settle southward a bit through the
overnight, but not quite sure if this is enough to keep or develop
some convection beyond mid evening.

This update lowered the pops some and removed the enhanced wording.
The hourly temperature, dew point and wind grids were adjusted based
on the latest observations, then the LAV/LAMP guidance was blended


Sunny, hot and humid Saturday with HI 100 or greater most areas
south and west of KBLM along the I95 corridor. Its also Day 1 of an
excessive heat warning. A heat advisory was issued for areas south
and east of the warning.

If the boundary/trough hangs up near the Mason Dixon line to ACY,
then the potential would exist for late afternoon isolated severe
thunderstorms Delmarva. Still plenty of instability there with
better 0-6km bulk shear.  There is a subtle indication in the
convergent wind fields for a more sizable area of convection
Delmarva and southern NJ late Sat.

Fcst elements were produced using a 50 50 blend of 12z/22 GFS/NAM
MOS guidance.


A cdfnt will be crossing the area Sat night and there cud be some
lingering pops especially early. High pres will build back in on
Sun. However both temps and humidity will be a bit lower on Sun,
so while it will be hot, it will be a little more bearable.

The heat returns with a vengeance on Monday, which at this point
looks to be the hottest/most humid day. Heat index values will be
in the 105-110 range in the urban corridor.

Heat headlines are being modified as follows...for the urban
corridor, an excessive heat warning will be issued through Monday,
and it may need to be extended for Tuesday. We will likely fall
short of criteria on Sunday, but it will still be hot. For Monday,
the excessive heat watch will remain in place for the area
surrounding the warning (that it was previously in effect
for)...basically the entire cwa, outside of the Poconos and Sussex
County NJ. Felt excessive heat warning was the best way to go with
high impact events in Philadelphia this upcoming week.

On Monday, low pres will be movg acrs ern Canada. Its assocd
cdfnt will move thru the region and will touch off shwrs/tstms in
a very hot and sticky ams.

Tue and Wed look genly dry but the front will stall to the s and
there cud be some low pops acrs the Delmarva extreme srn NJ.


The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.

Tonight...VFR overall. Isolated showers or thunderstorms possible
this evening mainly north of KPHL. There could be localized MVFR
visibility due to fog/haze toward sunrise. Southwest winds 10-15
knots with some gusts to 20 knots, diminishing to less than 10 knots
by late evening and becoming west to northwest overnight.

Saturday...VFR overall. There is a chance for an afternoon shower or
thunderstorm mainly in the vicinity of KILG, KACY and KMIV. Light
west-northwest winds in the morning, turning westerly in the
afternoon with gusts up to 20 knots. Winds may turn southwest at
KMIV, KILG, and KACY during the afternoon.

Saturday night-Sunday. VFR. High pressure. High confidence.

Monday-Monday night...Generally VFR. A chance of shra/tsra which
may briefly lead to MVFR/IFR. Gusty southwest winds 15-20 knots.
Moderate to high confidence. Lower confidence of MVFR/IFR and
precipitation coverage.

Tuesday-Wednesday...VFR. High confidence.


Through tonight...Southwesterly winds with gusts up to 25 knots
especially nearshore of New Jersey, with seas expected to build up
to 5 feet. The winds and seas should then subside before daybreak

Saturday...Sub small craft advisory conditions anticipated. Max
gusts around 20 kt.

OUTLOOK... Sat night-Sun...No marine headlines anticipated.

Mon-Mon night...SCA conds psbl with increasing wind ahead of
approaching cdfnt.

Tue-Wed...No marine headlines anticipated.

RIP CURRENTS...Added Cape May county to the moderate risk for the
formation of dangerous rip currents this afternoon so that all of
the NJ coast is now Moderate, while we`ve maintained low risk for
the Delaware Beaches. Confidence on how much southerly component
is a little below average so the moderate risk may end up low enhanced.
Essentially... a 3-4 ft chop driven by gusty southwest wind of
15-20 mph is near parallel to shore. This will create a decent
south to north long shore current and could result in some
surprisingly strong rip currents by mid afternoon along the NJ
shore, when also low tide occurs.

Saturday: The probability for the formation of dangerous rip
currents is Low.

Looking further ahead, with the Atlantic Basin still devoid of
tropical storms, the probable risk for the formation of dangerous
rip currents should be low this weekend, especially with lighter
winds and tendency more of an offshore component.

Next Monday the 25th, we might have enough wave height to around
4 feet late in the day and water buildup due to southerly winds,
to have a more widespread low enhanced or even moderate risk but
confidence on seas building that high is below average.

Water temperatures fell about 4 degrees between 6 am and 10 am,
implying upwelling. Values were variably down into the mid 60s to
lower 70s....colder along the NJ coast. Even colder upwelling may
develop Saturday when the wind turns more westerly.


Record high temperatures Saturday through Thursday.

       23rd    24th    25th     26th     27th    28th
PHL 101-2011 98-2011 96-1899 101-1892 101-1940 100-1941

ABE  99-1955 95-1999 95-1999  98-1940  98-1955  97-1949

ACY 105-2011 100-2011 99-2010 96-2011&1963 99-2005  98-1999

ILG 100-2011 98-2011 96-1987 99-1894   100-1894 101-1894

TTN 104-2011 98-1910 97-1999 99-1892   100-1894 101-1894

GED  104-2011 99-2011 99-2010 97-2012  98-2005  99-1949

RDG  100-2011 96-2010 96-1999 99-1940  98-1955  99-1941

MPO   91-1955 91-1914 90-1999 89-1949  91-1955  93-1949


PA...Excessive Heat Watch from Monday morning through Monday
     afternoon for PAZ060>062-101-103-105.
     Excessive Heat Warning from 11 AM Saturday to 6 PM EDT Monday
     for PAZ070-071-102-104-106.
NJ...Excessive Heat Watch from Monday morning through Monday
     afternoon for NJZ007>010-012>014-016-020>027.
     Heat Advisory from 11 AM to 8 PM EDT Saturday for NJZ012>014-
     Excessive Heat Warning from 11 AM Saturday to 6 PM EDT Monday
     for NJZ015-017>019.
DE...Excessive Heat Watch from Monday morning through Monday
     afternoon for DEZ002>004.
     Heat Advisory from 11 AM to 8 PM EDT Saturday for DEZ002>004.
     Excessive Heat Warning from 11 AM Saturday to 6 PM EDT Monday
     for DEZ001.
MD...Excessive Heat Watch from Monday morning through Monday
     afternoon for MDZ008-012-015-019-020.
     Heat Advisory from 11 AM to 8 PM EDT Saturday for MDZ008-012-
MARINE...Small Craft Advisory until 5 AM EDT Saturday for ANZ450>453.


Near Term...Gorse
Short Term...Drag
Long Term...Nierenberg
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