Area Forecast Discussion
Issued by NWS State College, PA

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199
FXUS61 KCTP 191051
AFDCTP

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

.SYNOPSIS...
An anomalous upper level ridge will remain parked off the
southeast coast through the next 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 oscillate in the
vicinity of Pennsylvania late this week into next weekend.

&&

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

As spotty light rain arrives this morning, temps could be just
cold enough for some fzra on the ridgetops of central Pa. Have
not mentioned in the HWO due to marginal temps and very localized
nature of potential impacts.

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 thte 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 /10Z MONDAY THROUGH FRIDAY/...
High pressure will pass off the Mid Atlantic coast tonight as a
warm front approaches from the Ohio Valley. A developing
southerly breeze will bring LLWS in late, especially over the
western portion. This will also aid in spreading stratocu
restrictions in from the SW predawn Monday, with light rain and
more widespread restrictions prevailing during the day Monday.
Expect cigs and vsbys to degrade overnight into early tomorrow
beginning between around 09Z and continuing through the morning
and the first half of the afternoon. Conditions will slowly
improve late Monday.

Outlook...

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

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

Thu-Fri...Restrictions probable in rain showers.

&&

.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
NEAR TERM...Fitzgerald
SHORT TERM...Fitzgerald
LONG TERM...Fitzgerald
AVIATION...DeVoir/Ceru
HYDROLOGY...



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