Area Forecast Discussion
Issued by NWS State College, PA-- Remove Highlighting --
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FXUS61 KCTP 281151
Area Forecast Discussion
National Weather Service State College PA
751 AM EDT Tue Mar 28 2017
An area of low pressure will move along the Mason-Dixon line
through tonight...bringing showers to central PA and isolated
thunderstorms to southeastern sections today. High pressure
will build down out of southern Canada and bring cooler and
drier weather for Wednesday and Thursday.
A new storm system will approach for the end of this week with
the potential for more inclement weather.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Scattered to numerous showers have now overspread central and
western PA this morning, with isolated showers and a few rumbles
of thunder having been seen across the Lower Susq River Valley
over the past 90 minutes. As expected, regional radar mosaic
shows a broad swatch of showers extending from northeast Ohio
to the Northwest PA Mountains in the vicinity of persistent
850-700 frgn forcing...and this area will be the wettest
throughout the day. Most areas will see at least scattered
showers today...eastern and northeast areas seeing the least as
sfc low pressure tracks ESE across the southern tier of PA.
The sfc low tracks first into southwest PA later this morning then
propagates ESE to the Chesapeake Bay region by tonight. Clouds
and rain will keep highs over the northwest in the mid to upper
50s. Farther south sct to nmrs showers are expected across the
central and south central portions of the commonwealth. Thin
breaks in the overcast will allow temps to range generally in
the lower 60s. Along the southern tier, readings will range from
the upper 60s to perhaps the low 70s if warm sector manages to
lift north of the PA/MD border.
The guidance still continues to indicate instability lingering
over southeastern and south central areas through this
afternoon, and will maintained slgt chc thunder there with just
General thunder outlooked.
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
Showers will be on the decrease this evening as the low exits
off of the mid Atlantic coast. Slightly cooler and drier air
will overspread the region overnight...but there may be areas of
fog due to the widespread daytime rainfall. Mins will range from
the lower 30s north to the mid 40s south.
Wednesday should be a relatively nice day (though with some mdt
northerly wind gusts at times, as high pressure builds in from
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
The dry air and high pressure are in all of the most recent
guidance, implying Wed ngt and Thursday will remain dry and
High pressure, dry air, and normal to slightly below normal 850
hPa and 925 hPa temperatures imply near normal daytime highs.
Most of the 26/00-06Z U.S. and int`l model guidance (and EFS)
indicates more of southern...shearing storm track for late in
the week...thanks to a stronger and more wwd position of a deep
nrn stream vortex across the Canadian Maritimes.
The trend of the big model discrepancy for late this week and
this weekend (between the GFS and EC over the past several days)
has trended toward the GFS and its ENS members with southern
stream energy and its moisture being prevented from amplifying
with an associated storm track to our west.
Rather, what we see is a shift of the primary southern stream
sfc low track to our south as the potent midweek southern stream
sfc/upper low (that will be trying to take the turn northeast
across the Mid Miss Valley twd the Great Lakes) encounters great
resistance from the notably stronger WNW upper jet core
defining the northern stream that will be situated from the
Upper Glakes to the Mid Atl Coast.
With this type of consensus storm track, pops will be somewhat
less for Friday and Saturday (compared to a heavily weighted
EC/ECENS solution) and limited to mainly the southern half of PA
where some rain (or even an elevation-dependent rain/wet snow
mix) with expansive cooler and drier air north of PA.
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
Lowering cig/vis trend continues this morning with widespread
MVFR to LIFR. Rain showers overspread the airspace through mid
morning and continues through the afternoon before tapering off
from NW to SE this evening/into tonight. A drier northerly flow
should translate into improving conditions on Wednesday.
Wed...A.M. restrictions; becoming VFR.
Thu...VFR/No sig wx.
Thu Night-Fri...Sub-VFR restrictions/rain likely.
Sat...Gradually improving conditions.