Scientific Forecaster Discussion
fxus61 kctp 232132
Area forecast discussion
National Weather Service State College PA
532 PM EDT Tue Jul 23 2019
cooler and much less humid air arriving today in northerly
flow. A trough aloft will slowly swing across the state this
week with a surface high pressure system following doggedly
after. Warmer and more muggy air will be returning later in the
week and for the weekend as the high pressure moves off the East
Near term /through Wednesday/...
main player today is upper trough that will take its time
swinging through over the next few days. Though airmass is much
drier in lower levels, cooler air aloft helping to produce
enough instability/cape to generate isolated to scattered
showers and a few tstms along an 850mb north/S oriented convergence
line extending from roc to bfd to mgw. A localized wind gust to
30 mph will be poss near any tstms. These will slowly drift
eastward just another County or two over the next several hours
before dissipating early this evening. Clouds will also linger
through the daytime before decreasing overnight, with patchy fog
forming in the deeper valleys of the northern mountains as lows
there drop into the 50s (lows around 60 in the susq valley).
Wed looks like a smaller version of today. With trough still
lingering, more isolated showers again look to pop
midday/afternoon generally over the northwest and laurels.
Short term /Wednesday night through Friday night/...
a rather deep (seasonably-adjusted) upper level trough over cpa
at the start of the period will gradually deamplify into the
weekend. High pressure will dominate the surface pattern as it
migrates slowly eastward from the Ohio Valley off the mid
Atlantic coast by Saturday morning. A pocket of cool air aloft
may combine with diurnal heating to produce a few spotty showers
over the northern tier during the afternoon on Thursday and
Friday. Otherwise, expect an extended break from the heat and
humidity with mostly dry and pleasant conditions, plenty of
sunshine, and comfortably warm afternoons/cool nights.
Long term /Saturday through Tuesday/...
rainfall potential will slowly increase during the period as
more typical summertime pattern becomes established over the
region. Model and ensemble guidance show a frontal system
approaching the area early next week, offering the highest
chance for showers/T-storms.
Aviation /22z Tuesday through Sunday/...
a broken line of shra/tsra has developed over the higher
terrain along the Allegheny Front. A brief downpour and a
localized wind gust to 30 mph is possible in any of these
storms as they slowly drift eastward over the next few hours.
This activity could impact kjst, kaoo and kunv before
dissipating later this evening.
Otherwise, a broken deck of mid-level clouds will continue to
drift overhead this evening. Clouds should decrease overnight,
with patchy fog forming in the valleys of northern PA.
Wednesday looks similar to today. With an upper-level trough
still lingering, isolated showers may again pop up during the
afternoon over the higher terrain. Overall, however, expect VFR
conditions and light northerly winds.
Excellent flying weather continues into the weekend.
Wed-sun...no sig wx expected.