Area Forecast Discussion
Issued by NWS State College, PA

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000
FXUS61 KCTP 242057
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
357 PM EST Fri Feb 24 2017

.SYNOPSIS...
A strong cold front will plow east across the region on Saturday
and create showers and perhaps a narrow line of strong, gusty
thunderstorms. Gusty westerly winds and colder temperatures will
follow the frontal passage. Some snow showers are also expected
late Saturday and Sunday in the western highlands. High
pressure builds in from the Ohio Valley for Sunday but weak
waves of low pressure will move up the Ohio River Valley Monday
into Tuesday may bring some mixed precipitation to the northern
half of the area, and mainly rain in the south.

&&

.NEAR TERM /UNTIL MIDNIGHT TONIGHT/...
Temps on track and crazy high for late Feb. See Climate section
for more. Southerly wind will continue all evening, but should
be weakening after sunset.

&&

.SHORT TERM /MIDNIGHT THROUGH 6 PM SATURDAY/...
Takeaways: CFROPA expected around 12Z W and 18Z E. SHRA/TSRA
along and behind the front. Some will be strong/gusty. Severe
not out of the question, but risk still only MRGL in newest DY2
outlook from SPC. Gusty post-front but not wind advy-worthy.

Overnight: The SSE flow up into the mountains will lead to low
clouds and they may get thick enough to produce some drizzle or
even very light showers overnight. The faster the clouds thicken
up, the warmer it will stay overnight. Will run with mins in the
50s. (Yes, it just seems plain bizarre writing that in late
Feb.)

The clouds will also make it tough to destabilize during the
morning - esp in the NE where the --precip may be lingering
into the first part of the day. The front will push across
steadily and only taking about 6 hours to cross the entire CWA.
POPs will be pegged at 100s.

Temps will drop very quickly and should be back into the L-M30s
in the NW by the end of the aftn. SHRA will turn to SHSN there
in the aftn. Winds will be gusting into the 30s with some peaks
in the 40s behind the front. But, at this point, it does not
look like a wind advy is necessary.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...

The mid range models all have similar timing for FROPA. the
front should be east of central PA by 00Z Saturday. Cold
northwesterly flow could allow for snow showers Saturday night
into Sunday. However lack of moisture will only bring light
accumulations with the highest amounts in the NW mtns.

After some morning flurries and scattered snow showers in the
NW Sunday, the trough will continue its eastward trek and a more
zonal pattern will overtake the region. This will bring more
tranquil conditions with some sunshine expected for Sunday
afternoon, along with decreasing winds.
 However, max temperatures on Sunday will be back to near
normal. Heights are forecast to rebuild across the eastern
half of the conus early next week on broad southwesterly flow
ahead of troffing developing over the Rockies.
 The latest 12Z runs show a warm frontal boundary moving into
the region Tuesday. This will bring the next chance for
precipitation with possible warmer than normal temperatures
though not as high as currently. Another upper level trough
moving through the Great lakes could bring another cold front
through the mid Atlantic region later next week. There are
inconsistencies in timing and placement.


&&

.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
VFR for more than the first half of the 18Z TAFs in most while
the southerly flow moistens things up. Late this evening or
early in the night the southerly flow will make low clouds over
the area - thickest/lowest in the NE. There might be some
drizzle or very light showers there overnight due to the
upslope and increasing moisture. Will drop most locations to
MVFR in the middle to end of the night. Then the cold front
will be the main focus of precip. Just a few showers are
expected along or ahead of the front, with much of it along or
even behind the front. But, it should pass through quickly.
Timing of onset of TS/SHRA will be around 12Z in the western
terminals and before 18Z in the east. Gusty winds are possible
in any TSRA, and post-frontal winds will line up nicely as
well. LLWS will be likely with srly 925mb winds up to 35KTS and
stable llvls in the east. LLWS possible W but it may just remain
gusty/mixed all night.

Directional shear behind the front would limit snow showers.
Highest chance for snow showers would be BFD, as the cold air
will be a little deeper there. r concern will come after
midnight, when radiational cooling leads to areas of low
CIGS/fog.

Outlook...

Sun...Windy. SHSN W in AM.

Mon...Light mixed precip poss/reduced CIGs/VIS.

Tue...Widespread SHRA/reduced CIGS possible.

Wed...CFROPA. SHRA/TSRA pre-front. IFR likely and windy post-
front.

&&

.CLIMATE...
***February Warmth 2017*** Updated 2/24/17 at 5 am EST

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

Harrisburg 2/24: 75 in 1985; all-time Feb record is 78F

Williamsport 2/24: 71 in 1985; all-time Feb record is also 71F

Altoona 2/24: 69 in 1985; all-time Feb record is 74F

Bradford 2/24: 59 in 1961; all-time Feb record is 64F

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

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
Evening cooling will be a little slower than last
night.
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...Dangelo/Lambert
NEAR TERM...Dangelo
SHORT TERM...Dangelo
LONG TERM...Ceru/Gartner
AVIATION...Dangelo
CLIMATE...



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