Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Mount Holly New Jersey
1148 am EDT Tuesday Jul 22 2014
weak high pressure will remain across the area today...before
moving east tonight. Low pressure will move across southern Canada
and bring a cold front to our area Wednesday through early
Thursday. More high pressure will follow for Friday and Saturday.
Another low and its associated fronts will affect the weather for
Sunday and into early next week.
Near term /until 6 PM this evening/...
high pressure was centered from eastern Virginia to the waters
off the Delaware-Maryland-Virginia coast late this morning. The high will continue
to drift out to sea this afternoon.
A developing southerly surface flow will continue to bring low
level moisture into our region. Additional cumulus will develop
over northeastern Maryland, northern Delaware, eastern
Pennsylvania and New Jersey for the early to middle afternoon hours.
A weak short wave in the middle level flow may touch off isolated
showers and thunderstorms in the northern part of our region for
this afternoon. The slight chance of precipitation is confined
mainly to areas to the north of Interstate 78 from the Lehigh
Valley eastward into New Jersey.
Maximum temperatures will be mainly in the 80s.
Short term /6 PM this evening through 6 am Wednesday/...
a tad milder than it was this morning with mostly clear
skies...light S-SW wind and patchy St/fog late at night...mainly
east PA and northwest New Jersey. Any showers from the afternoon hours should rapidly
dissipate before 00z/23.
This was a 50 50 blended 00z/22 NAM/GFS forecast.
Long term /Wednesday through Monday/...
Wednesday through early Thursday...a cold front will be west of
the area Wednesday morning and it will cross the area Wednesday
afternoon and overnight. Showers and thunderstorms are expected with the
frontal passage. The Storm Prediction Center does not have our area in a slight risk for severe on
day2...but the area is to the north across New England...the 5pct
line is across NE PA and northern New Jersey...so we will monitor this further
later today. A few showers may linger across southern New Jersey and the
Delaware-Maryland-Virginia into Thursday morning. Wednesday will feature hot and humid
conditions with highs in the upper 80s and low 90s. Apparent temperatures
in the middle/upper 90s most areas.
Later Thursday through Saturday...improving weather with high pressure
moving into the area. Lower dew points and temperatures mostly low
80s across the area. The GFS model is showing a few showers Sat
afternoon...but have decided to keep them out for now with the
better chance for rains arriving later Sat and into Sunday.
Sat night through early next week... the weather worsens Sat
night and poor conditions expected into early next week with a
upper low and series of fronts slated to affect the area. There
will be at least chance probability of precipitation each day...sun through Tuesday...with thunderstorms
possible during the afternoon periods. Temperatures will be a few
degrees below normal for late July with plenty of clouds expected.
Aviation /16z Tuesday through Saturday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg,
kilg, kmiv, kacy and surrounding areas.
MVFR ceilings in eastern Pennsylvania and over the far upper
Delaware-Maryland-Virginia should continue to lift into the VFR range during the
early afternoon with ceilings rising to 3500 to 4500 feet. The
cloud cover is forecast to decrease during the late afternoon and
VFR conditions are anticipated for early tonight. Increasing low
level moisture in the southerly flow may result in the development
of some low clouds, haze and fog for late tonight.
A southerly wind around 5 to 10 knots today should diminish to 6
knots or less for tonight.
Wednesday...mainly VFR. Possible early morning MVFR or IFR
conditions in low clouds, fog and haze. A chance of afternoon
Wednesday night and Thursday...MVFR and IFR conditions at times
in showers and thunderstorms. Patchy fog Thursday morning.
Thursday night through Saturday...mainly VFR.
sub-Small Craft Advisory conditions are expected across the waters through
tonight. Seas remain nearly in steady state around 3 feet on the
Atlantic waters and 2 feet or less Delaware Bay. Winds generally southerly
with a few afternoon gusts 15 knots.
Wednesday through Saturday...sub-sca conditions expected. Occasional
thunderstorms on the waters Wednesday night may create locally higher winds and