Scientific Forecaster Discussion
Area forecast discussion
National Weather Service State College PA
1236 am EST sun Nov 23 2014
a warm front will move through the region overnight. An
approaching low pressure area will bring milder temperatures and
rain to the area Sunday night into Monday. Cooler air will return
midweek with a chance for rain or snow later Wednesday into
Thanksgiving day...followed by another shot of colder air for the
Near term /until 6 am this morning/...
cancelled Freezing Rain Advisory. The lingering isolated near
freezing mesonet temperatures over Clinton and Lycoming County are
warming above freezing currently...while radar indicates light
shower activity lifting well north of that area. Temperatures across the
remainder of northern PA are in the middle to upper 30s.
Light shower activity should persist for the next few hours before
dissipating as low level convergence is lost with the exit and dissipation
of low level jet into southern New England and 500 mb shortwave ridging
arriving from the Ohio Valley. Temperatures should remain steady or
slowly rise through dawn.
Short term /6 am this morning through 6 PM Monday/...
Bermuda high will keep good srly flow going. Early morning temperatures
in the 30s should allow for a run at 50f almost everywhere. The
snowpack in the far northwest could then keep them in the 40s. The
Heights rise for a brief time before a significant wave brings
higher clouds back into the south ahead of a widespread. Clouds
will probably hang tough in the northern two-thirds of the area.
Long term /Monday night through Saturday/...
the latest model and ensemble guidance continues to indicate a
highly amplified and active upper air pattern developing next
week. The 500mb configuration will feature anomalous ridging along
the West Coast and in the western Atlantic with a full-latitude
trough carving out over the central and eastern U.S.
Phasing of split-stream energy will yield a deep 980mb low /-3 to
-4 Standard mslp/ lifting northward through Great Lakes into southeastern Canada on
Monday...tracking to our west. Strong southerly flow ahead of the
trailing cold front will bring a surge of high precipitable water air into the
region...which will support widespread light to moderate rainfall
mainly Sun night. This high confidence forecast will keep probability of precipitation in
the categorical range. Surge of warmer air /850mb temperatures at or above 10c/
will bring highs on Monday well above normal into the 55-65f
range...pushing to near record highs and finishing about 10-20f
above normal. Warmup will be short-lived however as frontal passage Monday
night Ushers back in cooler air and return of westerly flow which
will bring some light snow showers to western higher elevations.
Confidence is increasing in colder to below average temperatures
heading into Thanksgiving and especially the weekend as the global
models and ensembles are suggesting persistence of the eastern Continental U.S.
Finally...there is uncertainty/low confidence in potential impacts
associated with potential wave developing in the western Atlantic during
the Wednesday-Thursday time period. This situation will continue to be
watched as the western periphery of the moisture shield may contain snow.
Solutions from the 12z Sat suite coming in with similar trends to
the 00z suite...both unfortunately with mixed solutions. Gefs
largely focused on a mostly offshore storm to affect the
fishes...while operational European model (ecmwf) shows much more widespread
inland snowfall impacts on Wednesday afternoon/night... one of
the busiest travel days of the year. Stay tuned.
Aviation /06z Sunday through Thursday/...
light rain showers continue across the northern terminals areas and will
do so into the early am. Only kbfd reporting sub VFR conds with
some MVFR ceilings. Near surface temperatures have risen above freezing most
locations...but ground temperatures near freezing could still lead to
slick spots on ground surfaces. Ceilings will likely lower for a
short time overnight as the rain has moistened up the lower atmos.
Low level wind shear should continue for the whole taf period.
Sunday will have little or no precipitation - only kbfd has a poss - but
it is too low to include at this point.
Monday...MVFR/IFR with widespread rain.
Tuesday...MVFR with snow showers over western high terrain. VFR
Wednesday and Thursday...MVFR/IFR poss east. VFR elsewhere.
near term...devoir/la corte