Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 252034
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
334 PM EST Sun Feb 25 2018

.SYNOPSIS...
A break in the wet weather pattern is expected into mid-week.
Above average temperatures are expected through much of the
upcoming week before a relative cooling trend toward
climatology for early March. Another wet period is Wednesday
night into Friday.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Time to stick the fork in it. I think it`s done. Showers along
the gusty sfc trough are shriveling up, and the shield of rain
over the SE is finally gone. Low clouds also gone over the NW,
and only high clouds left. High pressure builds (over the
entire area which experienced heavy rain these last few days
from TX to OH) tonight. Skies will clear of the low stuff, and
the high clouds should only linger over the southern half, but
even those should be thin after midnight. Mins tonight will be
typical of late March rather than late February - u20s NW to
u30s SE.

Very interesting wind changes happened progressively at JST-
AOO-HGR-THV-MDT-LNS today. The wind just to the west of the edge
of the rain shield suddenly swung very decidedly northwest for
an hour or less before going back to a more general S/SE
direction and became lighter. Now the main trough is catching up
and turning things all westerly for good. Neat to watch, but
certainly difficult to forecast. HRRR and RAP did not catch it,
but it was a trackable change and could have been significant to
aviation interests. As the wind direction changed it dropped JST
from 10sm visby to near zero in minutes. That low crud slid away
in less than an hour, though when/as the wind went back to a
light/srly vector.

Rainfall has been just shy of enough to make flooding at any of
our forecast points. Any small streams which are swollen right
now will be falling well back into their banks before morning.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
>1030mb sfc high continues to elongate W-E and build in
overhead through the day and Monday night. The center of mass
will be over VA by Tuesday morning, but cover from LS to ME to
the Gulf Coast. Dry weather will allow for lots of sunshine
Monday and a clear sky Mon night. Maxes under 8H temps of -4C
north and +1C south will be into the m40s to m50s. There will be
a westerly breeze with the high still off to our west, but that
should only help things to dry out nicely. Monday night looks to
be the coldest of the next few nights, and perhaps the only one
for many places to go below freezing. All the rain, sun and
above freezing temps will probably coax the early-season
perennials to poke out from hibernation.

The only location to monitor for any flooding would be near
Middletown as flow from the Swatara Cr and backwater from the
Susq clog together. The level there may tickle the 11 foot flood
stage for a day or more. Many other points will be above
caution, but below flood for a couple of days as well.
Thankfully, the weather looks dry into mid-week (segue...)

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
An active but progressive upper flow pattern will dominate
North America through the long term period. Ahead of the curve,
under upper ridging, the recent wet pattern looks like it will
take a break during the first part of the week before precip
risk increases next Wed- Fri. Mild and dry weather expected
through early Wed as high pressure ridge will be in control.

Model and ensemble guidance show a low pressure system tracking
east-northeast from the TX/OK panhandle across the Central
Plains/Midwest into the Great Lakes/Ohio Valley region by
Thursday. The ECMWF and GFS 12z runs beginning to converge on a
similar overall solution of strength and timing. First up will
be a warm front lifting through Thu night which could bring a
period of moderate rain to the area, and have raised pops
further during this period. Then attention turns to development
of a secondary low to the south of PA from the southern Mid
Atlantic piedmont that potentially settles in near the NJ coast
for a 12-24hr period Fri into Fri night. This is starting to
look more and more like we`ll have potential ptype issues or
wintry wx - esp over the northern half of CWA as colder drier
air wraps in from the NE. Could see accum snows in those areas,
and likely breezy conditions for the weekend. Something
definitely to watch at this range.

Temperatures will continue to run above average next week with
signs of trending cooler/closer to daily climate normals into
early March.

&&

.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
Main rain is gone and the wind shift and a few gusty showers
over IPT-HGR right now will be the last of any precip from this
system. The sfc high will build in and mainly across to our
south. This can be a helpful thing, as the wind will be more
westerly than northwesterly and hold less low level moisture
(from the lakes), allowing VFR sky. After slackening a little
tonight, the wind should increase to 8-12kts during the daylight
on Monday. Gusts could get as high as 20kts right on top the
ridges. The dry air should help keep the vsby up well above IFR
as well. The huge/sprawling high pressure will become centered
over VA Tuesday morning.

Outlook...

Tue-Wed...No sig wx.

Wed PM-Thu...Restrictions likely in periods of rain/low clouds.

Thu PM-Fri...Flight restrictions continue as rain could turn to
snow on higher elevations.

&&

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

&&

$$
SYNOPSIS...Dangelo
NEAR TERM...Dangelo
SHORT TERM...Dangelo
LONG TERM...Gartner/RXR
AVIATION...Dangelo



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