Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Mount Holly New Jersey
937 PM EDT Sat Jul 23 2016

Synopsis...
a very weak front will move off the Delmarva tonight. High
pressure will build over the area later tonight and through the
day Sunday. A weak cold front will cross the region Monday. High
pressure will return for the middle part of the week. Another
front may affect the area Thursday and Thursday night.

&&

Near term /until 6 am Sunday morning/...
except for a lone thunderstorm moving south through Talbot and
Caroline counties on the Eastern Shore, most of the action seen
earlier this evening has moved off the coast as a surface trough
moves east. Temperatures behind this trough remain warm...but with
dropping dewpoints, lower relative humidities will make conditions
feel better. Expect most of the overnight hours to be rain-free,
with lows in the mid-70s in the south, and mid 60s in the north.

The heat advisory expired at 8 PM. Another heat advisory is in
effect for Monday, with a break on Sunday due to lower relative
humidities and slightly lower air temperatures. The excessive
heat warning continues until 600 PM Monday for the urban corridor
around Philadelphia. Low temperatures overnight are expected to
range from the mid 60s in northeast PA and northwest New Jersey to mid 70s
in the urban areas and the coastal plain.

&&

Short term /6 am Sunday morning through 6 PM Sunday/...
the cold front will move south of the area by morning. The airmass
will be only slightly cooler behind the front. In northeast PA and
northwest NJ, where cold air advection is a bit more robust high temperatures will
be about 3-5 degrees lower than today. Farther south, expect only a
1-3 degree difference between tomorrow and today. However, drier air
will works its way into the region behind the cold front, so it
shouldn't be too humid outside of the southern Delaware and adjacent
eastern Maryland (where dewpoints will still be around 70f).

Forecast soundings show a subsidence inversion that should cap
convection with US located underneath the ridge. The forecast was
kept dry accordingly. Winds will be light and variable through the
day.

&&

Long term /Sunday night through Saturday/...
no huge changes foreseen in the Summer-like pattern with upper
heights remaining high across much of the U.S. The storm track will
be across southern Canada with short waves and weak low pressure
systems moving across the area. The weakening cold fronts associated
with these features will cross the area thru the week. The best chc
for showers and tstms will center around both Mon and Thu. We have
kept pops in the chc range for these periods with mostly dry or slgt
chc pops for other periods. The exact timing will depend on the
individual waves which the models have difficult resolving by the
end of the extended period. Pretty much all of the major models have
precip somewhere across the area Monday. Storm Prediction Center has a marginal risk for
severe storms across much of area then.

The above normal temperatures will continue thru much of the week.
Monday will likely be the hottest day with readings in the mid/upper
90s and heat index values in the 100s. The temperatures and dew
points will be lower for Tue and Wed, but still in the
uncomfortable/marginally unsafe range with heat index values 95-100
over the urban areas.

&&

Aviation /02z Sunday through Thursday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg, kilg,
kmiv, kacy and surrounding areas.

Predominately VFR thru Sunday. Some patchy fog may develop across
mainly the southern portions of the area later tonight, especially
if any precipitation falls at any of the terminals.

Light and variable winds are expected tonight. Winds at or below 10 kt on
Sunday.

Outlook...
VFR much of the time. Scattered (mostly) late afternoon and
evening showers and thunderstorms may limit cigs/vsbys at times
through the period.

&&

Marine...

Winds will be light tonight and Sunday with high pressure building
in.

Medium-period sly swells will persist today and tomorrow. Wave
heights should subside in the 2-3 ft range through the remainder of
the weekend.

Outlook...
mostly a period of sub-sca conditions expected. Scattered showers
and thunderstorms will create locally higher winds and seas
through the period.

&&

Climate...
record high temperatures today through Thursday are below.



Site 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 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

Ridge... 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

&&

Phi watches/warnings/advisories...
PA...heat advisory from 11 am to 6 PM EDT Monday for paz060>062-101-
103-105.
Excessive heat warning until 6 PM EDT Monday for paz070-071-
102-104-106.
New Jersey...heat advisory from 11 am to 6 PM EDT Monday for njz007>010-
012>014-016-020>027.
Excessive heat warning until 6 PM EDT Monday for njz015-
017>019.
Delaware...heat advisory from 11 am to 6 PM EDT Monday for dez002>004.
Excessive heat warning until 6 PM EDT Monday for dez001.
Maryland...heat advisory from 11 am to 6 PM EDT Monday for mdz008-012-015-
019-020.
Marine...none.

&&

$$
Synopsis...O'Hara
near term...miketta
short term...Klein
long term...O'Hara
aviation...Klein/miketta/O'Hara
marine...Klein/miketta/O'Hara
climate...staff

National Weather Service Glossary of Abbreviations