Scientific Forecaster Discussion
Area forecast discussion
National Weather Service State College PA
1019 am EDT Tuesday Apr 28 2015
Mainly dry conditions with moderating temperatures will occur
today and Wednesday. A complex low pressure system will bring
some showers to the area on Thursday and Friday. Improving
conditions are expected for the weekend.
Near term /until 6 PM this evening/...
The day started off bright over most areas. However we are still
chilly aloft so some stratocu clouds will start to bubble up as
as the strong April sun starts to warm the ground. Expect a mix of
sun and clouds as we enter the afternoon...but still a much more
pleasant day than the recent few.
Slowly rising heights aloft today will help temperatures climb to
more typical values for late April. It will still be breezy...a
good day for flying kites.
Short term /6 PM this evening through 6 PM Wednesday/...
looking at clearing skies tonight...as weak high pressure
Not seeing a threat of frost across the southeast at this point.
Only minor changes made to the forecast.
Long term /Wednesday night through Monday/...
looks like a wet period from late Wednesday night into Friday.
Some chance of a shower still from Friday night into Sunday.
However...took out mention of showers in this time frame...as
there was only a few spots that had them still in the forecast.
Otherwise...only very minor changes made in the longer term.
Southeast areas could see around .25 inches of rain...but central PA
may be mainly between the northern branch system and the cutoff
to the south. However...still think some areas across southern
PA could see .25 inches of quantitative precipitation forecast.
Earlier discussion below.
Evolution of the upper pattern appears consistent with at least
the last two days. Blocky/amplified but progressive split flow
pattern over North America is forecast persist through this week
then become more zonal during the weekend and into next week.
A slow moving southern stream upper low will emerge into the southeastern to
Middle Atlantic States during the midweek period. A distinct and rather
potent shot of northern stream upper energy...in the form of a closed
low dropping south-southeast from the upper glakes region...should capture
the surface low /progged by most model and ens guidance to be near
the Outer Banks of NC Thursday morning/.
Phasing of these features will coincide with the development of
highly anomalous east-nerly flow in the 925-850 mb layer late
Thursday into Friday across southern and eastern Penn. Precipitable waters in excess of
over 1 inch near the Delaware-Maryland-Virginia and southern New Jersey coast will be transported
nwwd up/over the shallow cold air entrenched across central Penn
and the susq valley. Thus continued the hiest probability of precipitation during the
period for Wednesday night into early Friday. Given the blocky nature of
the pattern...Wes reluctant in clearing our precipitation too fast Friday
Cool weather continues into Friday behind the departing upper
low. With rising heights over the weekend...temperatures should rebound
to near and slightly above normal into early next week. A northern
stream wave looks to bring showers and cooler temperatures back for next
Aviation /14z Tuesday through Saturday/...
All terminals are VFR as of middle morning...and should remain so
Surface winds from 300-330 will gust up to 20kts over the eastern
areas. A weak area of high pressure will move into the airspace
tonight-Wednesday with no sig weather expected.
Thu-Fri...VFR/MVFR in scattered rain showers.
Sat...no sig weather.
near term...la corte/Martin