Area Forecast Discussion
Issued by NWS State College, PA-- Remove Highlighting --
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FXUS61 KCTP 280816
Area Forecast Discussion
National Weather Service State College PA
416 AM EDT SAT MAY 28 2016
A ridge of high pressure will stay in place over the western
Atlantic, bringing very warm and increasingly humid conditions to
the region through much of the holiday weekend. Cooler and showery
weather may arrive for Memorial Day.
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
A mostly clear and warm night underway across central Pa beneath
building upper lvl ridge. Main issue will be some patchy fog
across the south central mtns, where sig rain fell yesterday.
Temps on track to bottom out from around 60f in the coolest
valleys of the north, to arnd 70f in Lancaster/Harrisburg.
.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM SUNDAY/...
Subtropical ridge builds nwwd into Pa on Sat with 500mb height
anomalies reaching 2SD across southeast Pa. The assoc warm temps
aloft should suppress convection across the se counties Sat aftn.
However, sct diurnal tsra again appear likely across the nw half
of the state. Thermodynamic/kinematic profiles appear very similar
to those on Friday, with moderate sfc-based cape of 1500-2500 j/kg
and weak low-mid level shear, suggesting pulse-type convection
and a low risk of organized svr wx.
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Summertime upper level ridge over the Mid Atlantic and Northeast
states is forecast to peak around 29/00z with above normal
heights returning to normal by early next week. Temperatures
should follow a similar trajectory with positive temp departures
trending modestly lower/toward climatology into the first week of
June. The tropical disturbance /Invest AL912016/ approaching the
Southeast U.S. coast will add additional moisture to an already
humid/unstable airmass in place through Memorial day weekend. Some
interaction between the tropical disturbance and mid latitude
trough crossing the Central Appalachians likely favors the
greatest pcpn risk/potential pcpn coverage Sunday night into Memorial
Day (Monday) with a decreasing chance for rain into Tuesday.
Deterministic and ensemble guidance are in broad agreement in a
dry period of weather from Tuesday into Wednesday before pcpn risk
gradually increases into the second half of next week. Heights are
forecast to rise a bit around the end of the period before the
large scale pattern slowly shifts toward a western ridge/eastern
trough configuration by June 5th as depicted by the 27/00z NAEFS
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --Ridge of high pressure remains in control, keeping a summertime
weather pattern in place.
Vsby reductions to MVFR likely around sunrise with humidity
continuing to gradually increase, with a few areas of IFR fog
mainly confined to places that receive rain Fri aft. Any reducing
conditions will lift between 12Z to 14Z.
Ridge will suppress convection and keep cumulus thin in the
southeast this afternoon. Chance for showers and thunderstorms
will be confined mainly to NW half. Overall conditions will remain
VFR, with local reductions in sct convection.
Sun...Sct afternoon tsra impacts...mainly nw half.
Sun night...Reductions likely mainly se half in showers/tstms.
Mon...Sct tsra impacts...mainly se half.
Tue and Wed...No sig wx.
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