Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Mount Holly New Jersey
1023 am EDT sun Sep 21 2014
low pressure off the Carolina coast will move northeast off the
middle-Atlantic coast today while a cold front approaches from the
west. The front is expected to move through the Middle-Atlantic States
tonight. High pressure building in from the Midwest early in the
week will persist over the area through the end of the week.
Near term /until 6 PM this evening/...
plenty of low level moisture lingering across the region this
morning. The moisture is rather shallow...so when it mixes out by
early this afternoon...temperatures should rise rather quickly. We
will hold onto the maximum temperature forecast from earlier.
Low pressure off the Delaware-Maryland-Virginia will continue to move
northeast...and it appears the rain shield will stay
offshore...just to the east of the coastal waters.
Low pressure will also move to the north and its associated cold
front will move toward the area from the west. Only slight chance of
small chance probability of precipitation across the northern/western areas. Added slight chance thunder
N/W. Public products updated just after 10 am.
Short term /6 PM this evening through 6 am Monday/...
the cold front will be the feature impacting our area tonight.
The front will move into the area this evening and then slowly
push its way through, making its way offshore by late tonight or
The front will have some showers associated with it and maybe a few
rumbles of thunder, although instability does not look at all
impressive. With the sun setting earlier at this time of year, we
will lose some of the oomph needed to help produce thunderstorms.
The front moves offshore late tonight and we will see a wind shift
to the northwest occur. Cooler air will start to move in toward
morning but will not arrive in time to impact overnight temperatures.
Expect lows to be in the 50s to lower 60s across the region.
Long term /Monday through Saturday/...
rather benign weather is expected through the entire extended
forecast period of Monday through Saturday. The cold front forecast
to move across the area tonight should be off the middle-Atlantic
coast by Monday morning. High pressure building in from the west
behind the front on Monday and Tuesday is expected to strengthen over New
England by Wednesday and Thursday...and then shift slightly west to the lower
Great Lakes and middle-Atlantic by Fri/Sat. Meanwhile an upper trough over
the eastern US on Monday will give way to an upper ridge building over
the region by middle week and continuing into next weekend.
The 12z European model (ecmwf) showed an upper low developing over the middle-Atlantic
by the latter part of the week. However this solution seems to be out of
line with other models including the Euro ensemble...according to
wpc...and now the new 00z European model (ecmwf) shows more of a weakness in the
upper ridge rather than a closed low. Still...with easterly/onshore
flow around the New England high pressure...have accepted wpc probability of precipitation
over Delaware-Maryland-Virginia and southern New Jersey for Thursday and Thursday night...but with a small
Low-level cold advection will be in place for Monday and Tuesday but should
become neutral by mid-week...with a warming trend by weeks end.
Aviation /14z Sunday through Thursday/...
the following discussion is for kphl, kpne, kttn, kabe, krdg,
kilg, kmiv, kacy and surrounding areas.
Today...very slow improvement in ceilings/visibilities through the rest of
the morning. Very light winds. Hopefully VFR by middle afternoon.
Winds will swing around to SW across the del valley late 5 to 10
Tonight...a cold front will cross the region tonight. Winds will
shift from the southwest to the northwest behind the frontal
passage. There is a chance for some scattered showers ahead of
and along the cold front. Best chances are later this afternoon
through this evening.
Monday...northwest wind gusts around 20 knots are possible Monday in
association with high pressure building in behind a cold front.
Some strato-cumulus may develop in this setup, which could may result
in a period MVFR cigs, most likely for ridge/Abe terminals.
Monday night through Thursday...VFR and light winds expected.
Small Craft Advisory dropped during the middle morning.
Seas will continue to subside through this afternoon before
starting to ramp up again as low pressure passes to the east of
our area waters.
Showers with embedded thunderstorms, associated with the low
pressure system to our south, will continue to move through the
waters this morning. Expect them to gradually move north and east as
the low makes its way up the middle Atlantic coast.
Monday and Monday night...a cold front will move through the waters
early Monday morning resulting in a wind shift from SW to northwest. Post-
frontal northwest winds of 15-20 knots generally expected but cannot rule
out locally stronger gusts on Monday into Monday night. With the
northwest flow seas could build up to 5 feet well offshore. However this
is not certain and with Small Craft Advisory currently in effect and a lull
expected this aftn/eve...will not issue another Small Craft Advisory at this time.
Tuesday through Thursday...sub-sca conditions expected for Tuesday and
Wednesday but increasing east flow by Thursday could build seas to near 5 feet...
especially Cape May and south.