Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 241103
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
703 AM EDT Tue Apr 24 2018

.SYNOPSIS...
A slow moving area of low pressure will produce a period of
rain for today into Wednesday. Expect dry but still cooler
than normal conditions on Thursday, but a brief shot of rain is
possible Friday or Saturday. Then, another stretch of dry
weather begins and lasts into next week as a huge high pressure
area moves in from the west.

&&

.NEAR TERM /UNTIL 7 PM THIS EVENING/...
Beautiful sunrise - red in morning. Lots of radar returns but
barely sprinkling. Still T/Td depressions of 12-20F this hour.
So, it is going to take a while to make it moist and get
efficient rainfall to occur over the east. The west is best -
for rain - today. Have trended POPs toward the latest HRRR/RAP
blend, slowing the eastward progression of the rain by several
hours.

Prev...
Arc of rain lifting through the central mtns is starting to fall
apart. The stronger reflectivities must be bright-banding as
they are right in that zone. Rain continues to fall apart a
little as it lifts north. More-coherent and better-forced
rainfall is not far behind this first volley, though.

Prev...
Radar shows a minor first volley of moisture/forcing moving
into/through the Laurels at 1 AM. T/Td depressions of 20+F mean
it could take a little bit of time for the rain to work down
from aloft.

An upper low and it`s attendant sfc low are currently sitting
over the TN Valley with a occlusion stretching to a triple point
over GA. The low closer to the coast will deepen through the day
as it moves into the Carolinas. The system/pattern is very
disorganized and things just don`t look like they are phasing up
at all. 3 or 4 different vort maxes will be spinning over the
eastern U.S. today, and none will help the other out. Good
srly/serly lljet will continue to increase the moisture through
the day. The second volley of rain should succeed in making most
of the area wet by sunset. It may take all day to get into the
NE mtns as the upper low doesn`t get too close (Smokies) by
sunset.

Temps pretty mild at 1 AM, especially considering the past few
weeks. However, they might not change much or even dip some in
the Laurels due to the rain/evap cooling and clouds. The
eastern zones could tack on 15F to morning temps as the rain
will advance only slowly eastward.

&&

.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
Main area of precip will likely be from the deformation
zone/WCB circulation to the northwest of the deepening sfc low.
The low will pass right over NJ on Wed. As the low moves to the
north along the coast, dry air will get pulled in from the NW.
The rain should be tapering off in the east during Wed AM. Other
than some SHRA over the NW and very highest elevations of
Somerset Co thanks to a ill-timed upper trough, the SE half of
the area should dry out nicely. The NW should dry out Wed
evening. Temps will dip into the 40s for everyone tonight. The
downslope and extra sun will help the SE get into the 60s, but
the rest of the area will be in the 50s in the afternoon without
much sun.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
The Thursday to Saturday period should be mainly dry with just
one potential weather-maker. That would be a northern-stream
short wave trough - or a southern stream coastal low like the
current one. Lots of uncertainty for Day3-4 right now. But, that
would be the only wet time until well into the middle of next
week. Temperatures will average near to slightly below average
during most of the period before trending noticeably warmer into
the first week of May.

&&

.AVIATION /11Z TUESDAY THROUGH SATURDAY/...
Band of mainly light rain over the office falling apart now.

Main change to the 12Z TAFS was to adjust fcst some for this
band, and extend fcst out into Wed morning.

Low pressure lifting out of the southeast states will spread
lowering and thickening clouds across central PA later today.

A few rain showers are working into the western airfields
early this morning. However, due to dry air at low levels,
expect VFR conditions to prevail.

Expect deteriorating flying conditions from SW to NE late today,
as the storm system and associated rain lifts up the east
coast. The biggest impacts will be over the southwest portion of
the forecast area, where model soundings and SREF prob charts
support IFR cigs/vsbys by early evening at KJST/KAOO. The most
favorable conditions will likely be in the vicinity of KIPT,
where VFR conditions will likely hold until evening.

Outlook...

Wed...AM rain/low cigs likely, then PM improvement.

Thu...AM low cigs possible W Mtns.

Fri...Slight chance of rain/low cigs.

Sat...AM showers/cig reductions possible NW Mtns.

&&

.CLIMATE...
April 2018 currently ranks in the top 10 coldest on record
(through the 22nd). Seasonable temperatures are expected through
the end of the month which should help to balance the cold
start.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$
SYNOPSIS...Dangelo
NEAR TERM...Dangelo
SHORT TERM...Dangelo
LONG TERM...Steinbugl
AVIATION...Martin
CLIMATE...Steinbugl


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