Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 301415

Area Forecast Discussion
National Weather Service State College PA
1015 AM EDT Sat May 30 2020

A noticeably cooler and drier, less humid airmass will move
into the area for the last weekend in May with temperatures
trending below normal to start June. Unsettled conditions
return by the middle of next week within a developing northwest
flow pattern as temperatures rebound near to above average.


Stellar morning in progress with refreshing dewpoints in the
upper 40s to around 50. Morning satellite clearly delineates a
secondary cold front dropping through northwest PA and eastern
Oh this morning. Earlier thinking was that a lake breeze could
spark an isolated shower mainly across the northwest and west
central mountains, but in addition to increasing cloud cover,
this feature is likely to focus isolated showers farther east
and south this afternoon into the central mountains as well
Fortunately moisture is limited with this system, but many will
see a stray sprinkle/shower in the aforementioned areas as the
boundary passes.

Max temps are forecast to be about 10 degrees cooler than
yesterday in the mid 60s to upper 70s or near-seasonal averages
for late May. Some low clouds may develop again across the NW
Alleghenies, otherwise expect mostly clear skies tonight with
lows ranging from around 40F in the northern tier to around 50F
in the Lower Susq. Valley.


Sfc high pressure will dominate the pattern and provide dry
weather into early next week. Temperatures will continue to
trend lower (cooler) and bottom out Sunday night. Main concern
is frost potential Sunday night/early Monday morning across the
northern tier with MOS numbers running a few degrees colder than
NBM. Official minT fcst (mid 30s) is slightly colder vs. NBM
which is probably a good bet given anomalous (+) MSLP and below
normal PWs. High clouds streaming in from the northwest could be
a limiting factor, but confidence is high enough now to mention
patchy frost in the usually colder spots in the northern tier.
The high will migrate to the Carolinas Monday night, leaving the
area vulnerable to disturbances dropping southeast from the
Great Lakes within a developing northwest flow pattern. Model
consensus shows an increasing chance for showers reaching NW PA
by 12Z Tue.


Early next week, models are in good agreement on an extended
period of NW flow as a large scale upper trough sharpens over SE
Canada and the Eastern US. An expansive sfc high pressure
builds back in across the Ohio Valley and drifts just south of
PA by Tue and then offshore by the middle of the week.

Quick hitting shortwave trough slides through on Tue and may
produce some scattered light showers. The longwave trough
flattens a bit briefly before sharpening again as large ridge
builds over central parts of the country. This will allow
another weak shortwave or two to ripple by overhead on Thu which
will interact with a leftover weak surface boundary (from Wed)
to keep mention of showers in the forecast.

The first half of next weekend is looking pleasant and dry.


A northwesterly breeze of 10-20 kts will develop as a secondary
cold front drops into the area from the Great Lakes, triggering
a few -SHRA from the Northwest Mountains to the Central
Mountains, but best chances over the western highlands /JST and
BFD/. Farther east and south, generally VFR conds are expected
to persist.

Sunday and Monday should be dry, but there could be fog in the
nrn valleys both Sunday and Monday morning. The next chance for
showers will arrive Tuesday with a weak system dropping
southeastward from the Great Lakes. A more significant system
will approach on Wed, with an increased chc of SHRA and TSRA.


Sun-Mon...AM Fog poss. Otherwise VFR.

Tues...Chc SHRA and MVFR conds, mainly NW.

Wed...Sct/nmrs SHRA and TSRA, esp N.




NEAR TERM...DeVoir/Steinbugl
SHORT TERM...Steinbugl
LONG TERM...Lambert/Banghoff
AVIATION...DeVoir/Evanego is the U.S. government's official web portal to all federal, state and local government web resources and services.