Area Forecast Discussion
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FXUS61 KCTP 270822
Area Forecast Discussion
National Weather Service State College PA
422 AM EDT FRI MAY 27 2016
A ridge of high pressure over the western Atlantic will bring warm
and increasingly humid conditions to the region into the holiday
weekend. Cooler and showery weather may arrive for Memorial Day.
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Radar mosaic at 06Z showing isold showers across central Pa in
advance of weak shortwave moving into the area. This feature is
progged to push east of the region by dawn, so will end mention of
showers from west to east btwn 07Z-10Z.
Lingering broken mid clouds for much of the overnight should
prevent anything more than than thin fog from forming. Should
there be a few spots that clear after seeing a shower, then
locally lower visibilities could prevail for a few hours until
just after sunrise.
Mins tonight will feel mid-summerlike in the 60s.
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
After a warm and tranquil morning, diurnal heating of moist
airmass should yield sct pm, pulse-type convection. NCAR ensemble
data indicating CAPEs surging to arnd 2000 J/kg, which could
support locally isold strong wgusts/hail in best cells. However,
wind fields and deep lyr shear are weak, indicating organized svr
wx is unlikely.
Although Pops are blw 50 pct, what rain does fall could be locally
heavy, due to slow storm motion and high PWATs. Convection-
allowing mdls show this potential with local amts in excess of 2
Mdl 850mb temps close to 16C are supportive of max temps today
ranging from the l80s ovr the highest terrain, to nr 90F over
the Susq Valley.
Partly cloudy skies...light wind and moderately high dewpoints Friday
night will lead to another mild night with the potential for light
fog late. Mins in the low-mid 60s will be common.
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
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 maxT departures of
+10-15F on Saturday /within 3-5 degrees of daily records/ before
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.
Widely scattered, diurnal convection remains probable Saturday
afternoon/evening with initiation likely triggering along the
Allegheny spine before drifting east. Some interaction between the
tropical disturbance and mid latitude trough crossing the Central
Appalachians likely favors the greatest pcpn risk/potential pcpn
coverage on Memorial Day (Monday) with a decreasing chance for
rain into Tuesday. The 26/12z 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 6th as depicted by the 26/12z NAEFS and 26/00z ECENS.
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
Ridge of high pressure remains in control. VFR conditions will
continue in most locales...however as temperatures drop and winds
go calm patchy fog/low stratocu should form. Most likely place for
statocu toward sunrise will be in the western higher terrain...
and fog formation will be most where rain fell on Wed afternoon.
Could see a several hour period of IFR cigs over the NW mtns and
poss Laurel Highlands as SREF prob data suggest.
Any reducing conditions will lift and/or dissipate by 15z...with
VFR prevailing on Friday. Another round of isolated/scattered
daytime convection is possible mid/late afternoon and early
evening, mainly in the south and east.
Sat...Early am low cigs possible. Isold pm tsra impacts possible.
Sun...Sct pm tsra impacts possible...mainly nw half.
Mon...Sct pm tsra impacts possible...mainly se half.
Tue...No sig wx.