Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 270737
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
337 AM EDT WED JUL 27 2016

.SYNOPSIS...
A weak front will stall to our south today into Thursday. A few
waves of low pressure developing along this boundary will result
in periods of showers and thunderstorms late in the week into
early next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Showers associated with an impulse traveling in the mid level flow
are forecast to pass across northeastern Maryland and Delaware early
this morning.

We are anticipating a mostly sunny sky for today over the northern
and central parts of our forecast area. It should be partly sunny
over our southern counties. Any cloud cover should be a combination
of cirrus associated with an upper level jet and daytime cumulus.

Dew point readings are expected to be mainly in the 60s in eastern
Pennsylvania and New Jersey and in the lower 70s in much of Delaware
and northeastern Maryland. Conditions are forecast to become
unstable in Delaware and northeastern Maryland, especially south of
the Chesapeake and Delaware Canal. As a result, we will mention
isolated to scattered showers and thunderstorms there for this
afternoon.

Maximum temperatures are forecast to be mostly in the lower 90s in
our region. Readings should not get out of the 80s in the elevated
terrain of the Poconos and northwestern New Jersey. Also, a
developing sea breeze should keep temperatures from rising above the
80s along the immediate coast.

Heat index values will likely be near or only slightly above the air
temperatures where dew points are in the 60s. Heat index values are
forecast to reach the upper 90s in much of Delaware and northeastern
Maryland due to the expectation of higher dew points there.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
The frontal boundary should remain to our south for tonight. We will
keep a slight chance of showers and thunderstorms in the forecast
for our southern counties. Otherwise, the sky should be in the
mostly clear to partly cloudy range.

The wind is expected to be light and variable and temperatures
should fall back into the 60s in our northern counties and into the
70s in the south.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
The chance for showers and thunderstorms will be on the increase
through Friday with a weak front in the area, potential waves of
low pressure along the boundary, and surging precipitable water
values. At this point it appears the highest chances will occur
during Friday as a stronger in a series of hard to time impulses
moves west to east across the region. The threat for severe
weather will be highest farther south during Thursday as
instability is limited for the northern areas. The latest SPC
outlook highlights a Marginal Risk across southern NJ, MD and DE.
A Marginal Risk will expand across NJ Friday however, expect the
potential for heavy rainfall/flooding to be a potential threat as
well. During Friday the precipitable water is projected to range
from 2 to 2.3 inches, which is above the 90th percentile for this
time of year. The precipitable water will remain around 1.5 to 2
inches during Saturday while the swath of higher values will be
displaced offshore in the wake of the aforementioned impulse.
Regardless, with a couple waves of low pressure expected along the
boundary unsettled weather will persist into the first part of next
week.

Max temperatures will be warmest during Thursday with afternoon
heat indices of 96 to 99. Otherwise, increasing cloud cover and
convection will limit max temperatures Friday through early next
week. Low temperatures each night will be a category above normal
through Saturday night, then near normal for the remainder of the
extended period.

&&

.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

VFR conditions are expected through the TAF period under a mostly
clear sky. The wind is forecast to be 8 knots or less. The direction
may favor the northeast to east for a time this morning before
switching to the southwest and south during the afternoon. The
direction is anticipated to be variable for tonight.

Outlook...
Thursday through Sunday...Mainly VFR conditions are expected.
However, the potential for shra/tsra Thursday through Sunday will
support tempo MVFR/IFR conditions at times.

&&

.MARINE...
The wind direction is forecast to veer from the north this morning
to the south for this afternoon into tonight. Wind speeds will be
generally 10 knots or less.

The ocean will be like a mill pond (in the words of our former
marine report relay Mrs. Cook) with wave heights of 2 feet or less.
Waves should be 1 foot or less on Delaware Bay.

Outlook...
Thursday through Sunday...Light and variable flow under a weak
pressure gradient early Thursday will become southerly around 10
knots with lower pressure across PA and weak high pressure farther
offshore. The pattern becomes a little more complex by Friday night
as low pressure may evolve near Delmarva. The low is projected to
move northeast during Saturday across the offshore waters. The
passage of the low would support light east winds Friday that would
back to a north-northeast direction and increase a notch Saturday
morning prior to lifting away later in the day. A weak pressure
gradient during Sunday would result in light onshore flow. Seas of
2 ft or less are expected during Thursday with a combination of a
minimal southerly wind wave and minor southeast swell. Multiple
higher frequency wave components are likely during Saturday given
the shifting winds with a dominant easterly wind wave taking hold.
Seas will subside some during Sunday. Advisory criteria is not
expected to be met at this time.

Rip currents...
There is a low risk for the development of dangerous rip currents
for today due to the relatively light wind and tranquil seas.

The probably risk for the development of dangerous rip currents on
Thursday is also low.

&&

.CLIMATE...
The last time the temperature reached or exceeded 98F at PHL was
three years ago on July 18, 2013. The last 100-degree day at PHL
occurred four years ago on July 18, 2012.

Record high temperatures for today and Thursday are below.

Site     27th       28th
----     ----       ----

PHL...   101-1940   100-1941

ABE...    98-1955    97-1949

ACY...    99-2005    98-1999

ILG...   100-1894   101-1894

TTN...   100-1894   101-1894

GED...    98-2005    99-1949

RDG...    98-1955    99-1941

MPO...    91-1955    93-1949

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...None.

&&

$$

Synopsis...Pfaff
Near Term...Iovino
Short Term...Pfaff
Long Term...Pfaff
Aviation...Iovino/Pfaff
Marine...Iovino/Pfaff
Climate...



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