Scientific Forecaster Discussion
Area forecast discussion
National Weather Service State College PA
738 am EDT Wednesday Apr 1 2015
high pressure centered over Ohio this morning will build east
over the region today...accompanied by fair and cool conditions.
Thursday will turn much warmer ahead of an approaching...albeit
slow moving cold frontal boundary. This front should stall out
across Pennsylvania Friday into Saturday...allowing a significant
wave of low pressure to form and ride northeast along
it...bringing rain then perhaps a changeover to wet snow across
central and northwestern Pennsylvania.
Near term /until 6 PM this evening/...
a few areas of scattered-broken strato cumulus and Alto cumulus were drifting across
the northern mountains early this morning...while skies were mainly clear
across the region from Interstate 80...south to the Mason-Dixon
line. High pressure will build east from Ohio this morning and
further diminish the already light northwest breeze.
Biggest concern for early today will be some patchy black ice where
wet pavement from yesterday/S snow has frozen up.
Temperatures at daybreak will be in the upper teens to middle 20s across
the northern mountains...and middle 20s to lower 30s across central and
NAM and high res models indicate the likelihood for increasing
stratocu and altocu clouds across roughly the northern half of
the County Warning Area later this morning...right through this evening /from the
combination of a few weak short waves embedded in the northwest flow
aloft...accompanied by pulses of weak southwesterly 850-700 mb warm air advection/isentropic
Highs this afternoon will be in the upper 30s across the
north...and around 50f in the far south...accompanied by partial
clearing and a 7-12 knots nwrly wind.
Short term /6 PM this evening through 6 PM Thursday/...
high pressure migrates east and over the area late today and
tonight...before sliding off the East Coast on Thursday.
Clear to partly cloudy skies will occur tonight/early Thursday
with light/variable or a light S-SW wind. Lows tonight will
be generally in the lower to middle 30s.
Middle and high clouds gradually increase/thicken-up from the west
Thursday afternoon and evening. Prior to that...we should see
temperatures reach the upper 50s to middle 60s /NW to southeast across the cwa/.
Long term /Thursday night through Tuesday/...
the pattern turns increasingly unsettled from Thursday into
Temperatures should be well above average ahead of the cold front
Friday. A good surge of moisture/precipitable waters ahead of the frontal waves
suggests a high confidence of measurable rain Thursday night-Friday with
the potential for 1+ inch amounts over a 24-36hr period ending 12z
Over the past few runs of the operational U.S. And Euro models
/along with the sref...and gefs/ there has been gradual...southeasterly
trend with respect to the track of the next significant wave of
low pressure forecast to develop and track NE from the Tennessee River
valley Friday into Saturday. This /second/ wave is prognosticated to
deepen steadily /to under 1000 mb/ as it crosses over the Upper
Middle-Atlantic region. This means that the potential is now there
for another round of significant...wet snow to occur across the
northwest half of the state.
A period of strong Post-frontal northwest winds appears likely on Saturday
on the backside of deepening surface low. The unseasonably cold and
gusty northwest flow will lead to a relatively cool/raw start to the
Easter weekend with a gradual warming trend expected into the
middle of next week.
Aviation /12z Wednesday through Sunday/...
12z tafs sent. No real change.
Expect a few lower clouds at bfd and jst early today.
Some higher clouds at times at other sites.
Still some lower ceilings at ipt and visibility down to 1 miles at
times...even with a west wind. Bfd down to 1/4mi in fog for
a brief time.
Other than these sites early today...looking at VFR conditions
today. Overall...a nice day compared to the type of weather we
have seen since late Nov.
Thursday morning...mainly VFR...as high pressure builds across the
Thursday PM-Fri...lowering conditions to MVFR with scattered rain
showers...as a cold front moves eastward. Gusty SW wind developing.
Sat...low probability for rain showers /mixed with snow showers north/.
Reductions poss mainly northern mountains
Sun...mainly VFR. Front will approach from the north late in the