Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 232023
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
423 PM EDT Thu Mar 23 2017

.SYNOPSIS...
High pressure will drift off of the eastern seaboard tonight,
allowing a warm front to lift into the region Friday. Patchy
sleet and freezing rain is expected over central and northern
areas from the early to late morning Friday before precipitation
changes to all rain. The rain front will stall along the New
York border, then oscillate in the vicinity of northern
Pennsylvania through early next week...separating milder air to
the south from cooler air  and showers north.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Temperatures this afternoon are peaking mainly in the 40s with
some mid-40 across central and southern Pennsylvania. A few cold
spots in the northeast mountain may not quite reach 40.

GOES-16 shows deeper clouds well to our west over Illinois so
the first part of the night will be mostly clear with some very
thin cirrus. Thus an initial rapid cool down before the clouds
arrive. The clouds arrive just in time to trap some of the cold
air but stop the cooling.

The HRRR is showing slower arrival of the QPF than older larger
scale guidance. But current model consensus brings a period of
precipitation across the commonwealth after 8-10 UTC...a
mixture of IP and ZR for many northwestern PA and some RA/FZRA
in central areas...which has prompted Winter Weather Advisory
issuance for the northern two thirds of central PA east of the
Alleghenies. The southern tier may see isolated or patchy
freezing rain...but confidence too low at this time for WSW
issuance as per collaboration with LWX, PHI.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
Model consensus keeps threat of fzra between 08Z-15Z
Friday...before changing to plain rain central and northeast.
Expect less than one tenth of an inch of ice as QPF is light,
but untreated roads could become slippery for morning rush.

WAA lifts north of the region with 850mb baroclinic zone by
midday Friday, indicating a dry and warmer afternoon across the
area. Models indicate surface warm front will work into the
central counties late in the day, pushing temps well into the
50s, while areas east of IPT and LNS will likely remain in the
40s.

&&

.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
At the outset of the longer term period the models are in fair
agreement in timing and strength. All are indicating a boundary
just to the north of Pennsylvania with a large upper level low
moving through the central midwest. A negatively tilted ridge
over the mid Atlantic will allow for stable but cloudy weather
into Saturday. Lows Friday night into Saturday should range from
the upper 40s to low 50s. There could be light rain showers on
Saturday but warm and stable. A cooler moist boundary should
move into the region Sunday out ahead of the approaching low.
Have adjusted POPs for timing and intensity. QPF remains
variable but possible wet period Sunday into Monday.

Above average temperatures are expected over the weekend with
the warmest day likely on Saturday with some sites approaching
70F over southern PA. Sunday should be markedly cooler behind
a backdoor cold front and a likelihood of rain. However, above
average temperatures (especially nighttime) appear very likely
through early next week, as 12Z GEFS indicates Pa remains
beneath a mean upper level ridge and plume of anomalous PWATs.
The chance of showers will spike with passage of next shortwave
Tuesday into Wednesday.

&&

.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
Widespread VFR flying through the period. High to mid level
clouds will increase tonight with surface winds veering to
90-160 degrees. Light precip will likely move across the
airspace between 06-18z Friday, starting as RA/FZRA/PL before
transitioning to all RA by 15z Friday. Added PROB30 group to
hedge toward brief period of ice mix around daybreak Friday.

Outlook...

Fri...VFR/MVFR. Pcpn ending after 18z.

Sat...Mainly VFR. Chance of rain northern 1/2 airspace.

Sun-Tue...Sub-VFR with periods of rain.

&&

.CLIMATE...
Minimum temperature records for 3/23 at select sites:

MDT: 14 in 1934
IPT: 8 in 1906
BFD: 5 in 1959
AOO: 15 in 1960

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 4 AM to 11 AM EDT Friday for
PAZ006-012-019-026>028-037-041-042-045-046-049>053-056>059.

&&

$$
SYNOPSIS...Fitzgerald
NEAR TERM...DeVoir/Fitzgerald
SHORT TERM...Grumm/DeVoir
LONG TERM...Fitzgerald/Ceru
AVIATION...DeVoir/Evanego
CLIMATE...


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