Area Forecast Discussion
Issued by NWS State College, PA

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000
FXUS61 KCTP 191327
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
827 AM EST Mon Feb 19 2018

.SYNOPSIS...
An anomalous upper level ridge will remain parked off the
southeast coast through the upcoming week. At the surface, a
warm front will approach Pennsylvania from the southwest today,
then push north of the area Tuesday. A dying cold front will
push southeast across the area late Wednesday, then stall in
the vicinity of Pennsylvania late this week into the weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

No change in the overall thinking of a warm front approaching
the region. Increasing warm advection/isentropic lift will
support an area of rain sliding across, mainly favoring the
northern 2/3 or so of my CWA. The leading edge of the steady
rain is moving into my NWRN zones and the HRRR shows this to
continue marching east while increasing on coverage throughout
the day.

The rest from earlier...


Model guidance continues to support a good chance of rain today,
as warm front lifts into western Pa, while wedge of cooler air
remains trapped east of the Appalachians. Highest POPS of near
100 pct are painted across northern Pa, where the best isentropic
lift is indicated at nose of low level jet coming through late
morning into the afternoon. Can`t completely rule out a rumble
of thunder across northern Pa, where a bit of elevated
instability is noted in the models.


HREFV2 and HRRR indicate the rain will be most widespread
during early afternoon, with the back edge of the steady rain
lifting north with the baroclinic zone and best isentropic lift
late in the day. Max temps are likely to range from the 50s on
the warm side of the front west of the Alleghenies, to the 40s
east of the mountains.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
All models indicating surface warm front becomes hung up along
the spine of the Appalachians tonight. However, isentropic lift
associated with low level jet and 850 baroclinic zone will shift
north of the state, causing rain to lift north of the NY border
this evening. Light wind and a moist boundary layer north of
surface warm front is likely to result in areas of fog across
the eastern half of the state tonight into Tuesday morning.

Model surface theta-E fields indicate the warm front will lift
north of the entire area Tuesday, flooding the area with near
record warmth. Even conservatively mixing to just 925mb should
yield max temps of around 70F over the southern part of the
forecast area, with slightly lower maxes across the northern
mountains and Middle Susq Valley.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
All med range guidance tracks a cold front through the region
Wed PM, accompanied by late day showers. Ahead of the front, ensemble
mean 925mb temps of near 16C should translate to another day of
near record highs, ranging from the low to mid 70s over much of
the region east of the Alleghenies.

00Z ECENS and GEFS both indicate cold front will stall out just
south of Pa Thursday, then oscillate in the vicinity of Pa into
next weekend. Thus, have included chance to likely POPs through
next weekend. Med range models do indicate there could be just
enough low level cold air for the potential of some fzra Thu
night or early Friday across northern Pa. Otherwise, ptype
appears to be all rain with broad southwest flow over the east
coast keeping temps well above normal.

&&

.AVIATION /13Z MONDAY THROUGH FRIDAY/...
A warm front will approach Pennsylvania from the southwest
today, then push north of the area Tuesday. Central PA will see
an extended period of LLWS with SW flow at 850mb hanging around
40-50 kts.

VFR conditions at 12z will give way to restrictions spreading
quickly across the region from the SW through mid/late morning.
Rain sliding in from the west will bring further reductions to
IFR as it impacts the west starting late morning and eastern
areas in the afternoon.

The light rain will come to an end this afternoon, with
conditions improving from the SW, where JST/AOO look to jump
back to VFR by this evening. But eastern sections look to remain
in the soupy air with lingering IFR conditions in low
clouds/drizzle through tonight.


Outlook...

Tue...Restrictions early east. Scattered rain showers and
restrictions NW mtns.

Tue night...Ceiling restrictions again likely eastern sections.

Wed...Restrictions likely in rain showers mainly NW half.

Thu-Fri...Intermittent restrictions in rain showers (light
wintry mix north).

&&

.HYDROLOGY...
Unlike the event last Thursday evening...the flow is less
west...east with the next system. Strong upper level ridging
should push the warm front to the north faster.

Thus QPF should be rather light across the area prior to 18Z
Wed. Heaviest QPF prior to this time will be likely across
northwestern Warren County Monday evening...with perhaps
isolated amts in the .50 to .75 inch range.

&&

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

&&

$$
SYNOPSIS...Fitzgerald/La Corte
NEAR TERM...Fitzgerald/La Corte
SHORT TERM...Fitzgerald
LONG TERM...Fitzgerald
AVIATION...RXR/La Corte

HYDROLOGY...



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