Thursday, March 23, 2017, 12:22 AM EDT
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Area Forecast Discussion
Valid At
Wed, Dec 31, 7:00pm EST
FXUS61 KCTP 221737

Area Forecast Discussion
National Weather Service State College PA
137 PM EDT Wed Mar 22 2017

A parting shot of mid-winter cold today and tonight before a 
more seasonable spring pattern returns temperatures to near or 
above normal levels through the end of March. A wintry mix 
remains possible early Friday morning before changing to rain. 
The weekend starts off very mild with rain likely by Sunday.


Subsidence and drying clearly evident on the WV imagery with 
strong high pressure building in. Dewpoints over much of PA also
have fallen into the single digits this afternoon. 

Cold/dry air continues to penetrate into Central PA via gusty
NNW winds (generally in the 25-30 mph range) in strong low 
level CAA. Temps will peak only in the mid 20s north to around
40 south, and when adding in wind chill effects today will feel
on the order of 40 to 50 degrees relative to yesterday!

The cold air is being supplied by a strong 1035+mb modified
arctic high pressure system that is drifting across the Great 
Lakes this afternoon to a position virtually overhead by 
daybreak Thursday. The abnormally dry air coupled with clear 
skies and light winds will result in a very cold night with 
minimum temperatures falling to near-record territory. See the 
climate section for 3/23 minimum temperatures records.


After a cold start, temperatures will begin to rebound as the
low level flow veers to the south/southwest. Highs Thursday will
be below average but it should feel warmer with very light winds
and plenty of late March sunshine. 

WAA pattern ramps up quickly Thursday night into Friday via 
anomalous west-southwest low level jet. Models continue to show
pcpn spreading into marginally cold/retreating and relatively
dry air near the surface between 06-12z Fri. Even with some evap
cooling/wet bulb effects, hard to see thermal profiles
supportive of snow unless the pcpn comes in very fast. Therefore
went with rain, sleet or freezing rain wx/ptypes which fits WPC
guidance. Ice accumulation will be hard to come by given temps
near 32F, warm surfaces and climo but will show a few hundredths
for storm total ice. Overall impact appears minimal but it only
takes a small amount of ice to cause problems especially during
the early morning commute. Temps should climb above freezing by
mid morning Friday ending the risk for ice. 

Rain focus should shift north into NY Friday afternoon into 
Friday night as baroclinic zones sets up in upper level
confluence zone downstream of deep cyclone moving through the
Southern Plains. The boundary placement will be key to the fcst
but it looks for now that most of the area will be in the mild
warm sector.


The models and ensembles continue to show a series of upper
troughs progressing onshore from the Eastern Pacific and across
the Southwest/South-Central Plains before deamplifying as they 
move east of the MS River. The first of 3 upper troughs emerges
from the Southern Plains and crosses into the MS Valley Sunday
and continues to weaken as surface frontal wave translates
downstream crossing the OH Valley/Great Lakes into the northern
Mid Atlantic states by Monday. Blend of NBM/ECENS/WPC still 
indicating max POPs in the Sunday-Sunday timeframe. 

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 also be mild but a bit
cooler due to the likelihood of rain. Fcst issues pertaining to
a backdoor cold front appear to be confined to New England early
next week with temperatures remaining near or or above climate
averages into early next week.


Subsidence and drying clearly evident on the WV imagery with 
strong 1035mb high pressure building in. 

VFR conditions areawide with gusty NNW winds (generally in the 
25-30 mph range) in strong low level CAA. These will taper off
late this afternoon into the evening hours as center of high 
pressure moves directly over PA by Thu morning. 


Thu...No sig wx expected.

Fri...Showers/reduced CIGS possible, mainly BFD.

Sat-Sun...Showers/reduced CIGS possible.


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




NEAR TERM...Steinbugl
SHORT TERM...Steinbugl
LONG TERM...Steinbugl

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