Scientific Forecaster Discussion
Area forecast discussion
National Weather Service State College PA
1133 PM EDT Sat Aug 30 2014
increasing moisture along with a trough of low pressure will
produce isolated showers and thunderstorms overnight. It will be
much milder as a result of southwest flow across the region.
Showers and thunderstorms will become more numerous on Sunday.
Warm and humid conditions will continue through Labor Day withi
still a chance of afternoon showers or thunderstorms before a cold
front brings a break in the humidity for middle week.
Near term /until 6 am Sunday morning/...
low clouds continue to hang tough over the eastern third of
central PA. Farther west...increasing deep layer moisture
continues to bring thickening layered clouds to western and
central areas...and isolated showers are weakening over the north
central mountains as well as the south central mountains late this
A diffuse warm front and the approach of an upper trough justifies
the continued mention of showers overnight...with activity focused
mainly over the northwest as moisture continues to pool there. A
muggy night is in progress with dewpoints in the middle to upper 60s
everywhere...keeping low temperatures some 10-15 degree above average in
Short term /6 am Sunday morning through Sunday night/...
Sunday will be a muggy and warm day. Showers and scattered
thunderstorms will abound...working slowly from northwest to southeast through
the day. Precipitable waters of 1-3 Standard dev above normal will provide the fuel
as shortwave energy ejects out of the miss/tenn valleys up the
western side of the subtropical ridge and into the northestern US.
Sref/gefs both show a near certainty of measurable rains...while a
blend of all model probability of precipitation is lower...in the likely ranges.
With an anomalously strong low level jet and pure tropical
air...cannot rule out locally heavy rain in some of the
thunderstorms Sunday. With local nature of this...will mention in
severe weather potential statement but will not be issuing any flood watches at this time.
Highs will not be terribly high...in the middle 70s to middle 80s from
northwest to southeast...but dewpoints well up in the 60s to lower 70s will
bring one of the more uncomfortably humid days we/ve seen this
Long term /Monday through Saturday/...
a stretch of unsettled weather will be the main highlight for
early next week. Operational models show a front fizzling out
over the region Monday...and a stronger front swinging through the
state late Tuesday. High pressure will then build in for
midweek...bringing a few days of dry weather...before another
another front moves through for the upcoming weekend.
This upcoming week will be one of the rare extended periods of
warmer than normal temperatures we have seen this Summer. High
temperatures will climb to almost 90 across the south and east on
Tuesday ahead of the frontal passage. Then an upper ridge will
build over the eastern US for the second half of the
week...keeping high temperatures at or slightly above seasonal
normals for early September through next weekend.
Aviation /04z Sunday through Thursday/...
late evening satellite imagery shows stratus covering the eastern half
of the state...the result of moist southeasterly flow off the Atlantic
Ocean. Further west...widespread VFR noted across the western half
of the state.
All model data points toward deteriorating flying conds
overnight. Plume of high moisture is in place over central PA and
as low levels cool...expect lowering stratus over most of central PA. The
worst conds in the form of IFR ceilings are likely to be at kbfd late
tonight...where SW flow ascends the higher terrain of northwest PA. MOS
guidance indicating a dip to IFR ceilings across much of central PA
early sun am. However...based on latest sref output and expected
southerly flow rather than southeasterly...believe MVFR ceilings are more
likely from kaoo and kunv eastward. The best flying conds are
likely to be at kjst...where south wind downsloping the higher
terrain of the central Appalachians may keep conds VFR there
A trough of low pressure approaching from the Great Lakes will spread
a band of rain showers into northwest PA Sunday morning. Scattered rain showers/thunderstorms and rain will
develop ahead of this feature over the rest of central PA by Sun
afternoon. Localized visibility reductions are possible in any of these
showers. However...the biggest aviation concern Sunday will be the
possible low ceilings in the morning...especially kbfd. Predominantly VFR
conds are likely by Sunday afternoon.
Monday...am fog poss...especially West Mountains isolated PM thunderstorms and rain impacts poss.
Tuesday...scattered PM thunderstorms and rain impacts poss.
Wednesday...patchy am fog poss.