Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 231205
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
705 AM EST Thu Feb 23 2017

.SYNOPSIS...
Our extended period of very mild weather will continue into
Saturday. A strong cold front will push east across the region
and bring showers, and perhaps a narrow line of gusty strong
thunderstorms on Saturday. Gusty westerly winds, colder
temperatures, and snow showers across the western mountains will
follow the frontal passage for later Saturday into early
Sunday. A relatively wave of low pressure moving northeast up
the Ohio River Valley Monday may bring a few periods of light
snow, mixed with rain in the valleys of Central and Southern PA.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Another very mild early morning for late February with
temperatures ranging from the mid 30s to lower lower throughout
the Susquehanna Valley and Central Mtns, to the balmy l50s
across the cloud-covered western mtns where a weak upslope flow
was helping to create a bkn-ovc layer of stratus. However, nothing
more than some patchy drizzle and ridge top fog is expected
across the NW Mtns and Laurels early today.

plenty of Low clouds and mid-level moisture will make today
another struggle to see the sun. However, the extremely mild
start to the day (45-50F west and 35 to 40F in the east) will
yet again allow the temps to be very much above normal through
the whole day. A shearing "cold" front will dip down into the
northern tier late in the day before stalling out near the PA/NY
border overnight. POPs are a difficult call but trended to a
blend of the HRRR and rather high and extensive Nat`l Blend of
Models pops.

Any fog this morning across the eastern zones should take a
while to burn off with dewpoints so high. The warm sector and
the passage of a very subtle short wave trough may pop some
showers (and given several hundred J/KG of cape so early in the
season - isolated thunder) over western PA and allow them to
advect to the east during the aftn. The warm front itself will
be another focus for some convergence and sct showers/possible
TSRA. Max temps today will be even warmer than (Wed). 60s should
be widespread with the warmest numbers in the south.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
The front will probably stall out for a short time tonight
across nrn PA, but likely push northward as a warm front very
late tonight and Friday morning.

This feature will keep clouds around, and is yet another reason
to remain very high on temps for tonight. Mins will again be
between 45 and 50F area-wide.

Very mild temperatures will persist for the end of the
week, likely reaching records levels at least in some locations
once again Friday afternoon as a gusty south to ssw wind advects
warm and relatively moist air up from the south.

Precipitation chances will be quite low across the south on
Friday (where periods of sunshine will be mixed with varying
amounts/thickness of cirrus clouds), while the northern tier
counties of the state should see scattered showers during the
monring hours.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Upper ridging over the east coast at the start of the period
will be temporarily squashed as a decent northern stream
shortwave moves east through the Ohio Valley and across the
Middle Atlantic states over the coming weekend. This will bring
a pronounced cold front across the region during the day
Saturday. Heights are forecast to rebuild across the eastern
half of the conus early next week ahead of troffing developing
over the Rockies.

The aforementioned cold front will return temps to near or
closer to near seasonal normals for Sunday into early next week.

Several shortwaves withing the developing southwest flow aloft
will bring several weak fronts across the region. This will
lead to less than pristine sky conditions...but the time period
will be generally dry. However, enough low pressure lurking at
the surface could lead to a system of more significance sometime
during the week.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
At 7 AM, some low clouds and fog to the east and west, but much
of the area is not bad.

12Z TAFS sent.

Earlier discussion below.

A wide range of conditions at 5 AM. Some dense fog the last
few minutes at LNS. Mid level clouds across much of the area
has limited low clouds and fog formation. Coolest readings to
the east.

Expect conditions to improve some today, as a low pressure
system lifts northeast across the Great Lakes. Perhaps a few
showers across the northwest.

A deeper low will track across the Great Lakes late Friday
into Saturday. While temperatures will be on the warm side,
dewpoints are not fcst to be real high, which may explain
why the models have most of the rain on the back sice of
the cold front.

Outlook...

Fri...IFR/MVFR psbl early - mainly N. Chance of rain mainly N.

Sat...LLWS. Strong FROPA with sub-VFR likely in moderate rain
showers and sct TS. Post-frontal WNW wind gusts 25-35kts.

Sat night-Sun...Sub-VFR NW third with sct shsn. Gusty NW wind.

Mon...Reduced CIGs psbl in RA/SN.

&&

.CLIMATE...
***February Warmth 2017*** Updated 2/22/17 at 8am EST

Record high temperatures for select sites for Feb. 23-24:
----------------------------------------------------------

Harrisburg 2/23: 70 in 1985
Harrisburg 2/24: 75 in 1985

Williamsport 2/23: 70 in 1985
Williamsport 2/24: 71 in 1985

Altoona 2/23: 66 in 1977
Altoona 2/24: 69 in 1985

Bradford 2/23: 57 in 1977
Bradford 2/24: 59 in 1961

-----------------------------------------------------------

Most 60 degree days in February at Harrisburg. Based on the
latest forecast, add 4 more days to the list and finish tied
for second with 7 days.

1. 10 days in 1976
2. 7 days in 1930
3. 5 days in 1991, 1943
5. 4 days in 1997, 1985, 1954, 1939
9. 3 days in 2017, 2016, 1996, 1990, 1961, 1932, 1890

------------------------------------------------------------

Warmest February on Record (Avg. Temperature through 2/21)

Harrisburg: 2017 rank=4 (38.6)
1. 40.4 in 1998
2. 39.6 in 1976
3. 39.4 in 1954

Williamsport: 2017 rank=4 (35.4)
1. 37.0 in 1998
2. 36.1 in 1954
3. 35.6 in 2002

Altoona: 2017 rank=2 (36.5)
1. 37.4 in 1976

Bradford: 2017 rank=6 (29.3)
1. 32.3 in 1998
2. 30.1 in 2002
3. 29.6 in 2012
4. 29.5 in 1990/1976
-------------------------------------------------------------

&&

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

&&

$$
SYNOPSIS...Lambert
NEAR TERM...Lambert
SHORT TERM...Lambert
LONG TERM...Lambert/Gartner
AVIATION...Martin
CLIMATE...



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