NWS Forecast Discussion
070
FXUS61 KCTP 071628
AFDCTP
Area Forecast Discussion
National Weather Service State College PA
1228 PM EDT Sat Sep 7 2024
.SYNOPSIS...
A slow-moving cold front will push through Eastern Pennsylvania
this morning, then exit the state by mid afternoon. High
pressure will build into the region behind the front Sunday,
then remain nearly stationary over the region through all of
next week.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
The area of showers is staying rather steady-state as far as
width and intensity of the rain (not intense at all). Have
nudged the PoPs higher in the Lower Susq with the rainfall
knocking on the door. However, the threat for TS through the
time the precip exits is still pretty low. Not nil, but very
low since only Lanc Co is heating up appreciably. Gusts are
already touching 20KT in the highest elevs of the west. The MCS
over the LP of ONT is sustaining some TSRA there, and this
activity/forcing is on track to push across LE and into PA this
aftn. Thus, we`ll keep the chc TS in the NW, and have
expanded/increased the PoPs there, too.
Prev...
Radar loop at 11Z shows a dwindling line of showers denoting a
cold front, running from around KUNV to KELM. The front is
progged to make slow eastward progress today, taking until about
midday to clear the eastern edge of the forecast area. The
parent upper low and strongest large scale forcing is progged to
pass north of PA, so expect the band of frontal convection to
be most concentrated over the northern tier with lower POPs
further south.
Frontogenetic forcing associated with the right entrance of an
upper level jet streak will keep the chance of showers going for
a couple of hours behind the fropa. However, the arrival of the
dry slot should result in breaking clouds over the western half
of the forecast area by late morning and by afternoon in the
Susq Valley. Although the trend of increasing sunshine should
hold for the bulk of Central PA, cold temps aloft, combined with
lake effect moisture, should result in a good deal of stratocu
and scattered afternoon showers over the NW Mtns.
850mb temps working into PA behind the front are progged to be
well below seasonal averages, resulting in max temps ranging
from only about 60F across the N Mtns, to the around 70F across
the Lower Susq Valley, some 10-15 degrees below early September
averages.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH MONDAY/...
Scattered lake effect showers appear likely over the NW Mtns
into this evening, then mostly sunny and cool weather with
light wind is expected Sunday, as the upper trough lift outs and
surface ridging builds into the state. Mixing down 850mb temps
of around 7C yields expected highs Sunday afternoon ranging
from the low 60s N Mtns, to the low 70s over the Susq Valley.
Latest guidance indicates the upper low will begin to lift out
by early next week. However, a shortwave diving into the base of
the exiting trough is progged track over upstate NY and Northern
PA Monday afternoon. The associated weak clipper low and strongest
warm advection is progged to pass just north of PA, but can`t
rule out a few showers across the northern counties. 850mb temps
rebound fairly quickly ahead of this feature, supporting highs
mainly in the 70s.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Surface high pressure building into PA will provide dry weather
for this entire week and possibly even beyond given the pattern
that is setting up. Calm winds and clear night skies will also
allow for the possibility of morning fog to develop throughout
the week within the valleys of central PA. Temperatures will
start the week a bit below normal before a gradual warming trend
begins as the upper trough moves away and 500 mb heights begin
to rise. Temperatures will increase a few degrees each day with
highs in the upper 70s and low to mid 80s by Wednesday.
Widespread mid 80 high temperatures are expected by the end of
the week. Next week looks very similar to this week with chilly
nights with valley fog, comfortable/low humidity afternoons, and
plenty of sunshine.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
Wind has switched to the west for all terminals but LNS here at
14Z. The area/wide band of rain is still 60-90SM behind the
front at this point. This should help decrease the coverage of
the rain, but not by much per latest progs. Still, the area of
frontal rain should be to the east of all the Central PA
airspace before 18Z. The NW (BFD) is a different story with an
active MCS crossing the LP of ONT at 14Z. This area of forcing
and SHRA is on track to push across LE and into PA this aftn,
helping to enhance and expand the coverage of the SHRA already
being generated by the lake effect process. The warm lake water
should add some punch to the SHRA which already have good anvils
on them per vis imagery. We`ll add a mention (TEMPO) for TS at
BFD for 18-20Z trying to time the best lift. Downsloping
should help things improve more quickly over the rest of the
airspace.
Outlook...
Sun-Wed...AM Valley Fog North & Central; otherwise, no sig wx.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Fitzgerald
NEAR TERM...Fitzgerald/Dangelo
SHORT TERM...Fitzgerald
LONG TERM...NPB/Bowen
AVIATION...Dangelo/Evanego
NWS CTP Office Area Forecast Discussion
