Area Forecast Discussion
Issued by NWS State College, PA
FXUS61 KCTP 261141
Area Forecast Discussion
National Weather Service State College PA
741 AM EDT THU MAY 26 2016
A ridge of high pressure will set up shop over the western
Atlantic for the next several days bringing warm and increasingly
humid conditions to the region into the holiday weekend.
Cooler and showery weather may arrive for Memorial Day.
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
High and mid clouds cover the area right now and some sprinkles
likely falling out of the 10kft clouds. A better shower is headed
right for KBFD, but is working into 50F dewpoints. The winds
should be picking up from the south as the morning continues and
we get some mixing. The air is still fairly dry but is moistening
up slowly. Dewpoints are now mainly in the 50s but no 60s yet.
The clouds will create problems in the forecast for afternoon and
evening convection. The thickest patch of the mid clouds should
move across the fcst area W-E this morning before breaking up a
bit in mid-day. Peak heating should be coincident with a weak
upper shortwave which will slide across the region. This combo
should allow for cells to grow tall enough to produce thunder. The
amount, intensity and location of showers and thunderstorms will
depend highly on the amount of low level heating we can achieve
through the cloud cover. The highest POPs will be placed over the
Alleghenies where the elevated heating surfaces and proximity to
the best forcing will compliment each other. There may still be a
weak mid-level capping inversion in the morning. But, CAPEs are
progged to get rather fat in the afternoon = 500 to 1100J/kg. The
low shear environment will mean there will be little organization
to the showers/storms. SPC does not even put us in the marginal
risk. PWATs will be in the 1.25-1.5 inch range and the warm-cloud
layer more than 10kft deep today. There could be some heavy
rainers since they will be moving slowly - but at least they will
be moving today.
High temps should be a few degrees lower than Wednesday for most
places due to the cloud cover. The NW mountains may not get to 80
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM FRIDAY/...
Precip chances get much lower after sunset, but a few cells may
survive until close to midnight. Then the light wind overnight
could allow for fog to form as the moisture/dewpoints will be much
higher than the last few nights - especially after many places
have some rain on Thursday.
While there should be a lull in the showers later tonight and
Friday morning, the CAPE gets high again in the afternoon -
possibly much higher (maybe twice) than Thursday. However, even
with CAPEs in the 2000J/kg range, the models generate only
scattered convection. This may have more to do with a lack of
forcing as there is no short wave to help convection along. Will
hold the course with 30-40 POPs at this point with the better
chance for a shower over the ridges. Once again, the showers
should pop up over the mountains first - but may just rain
themselves out of existence with almost no shear at all. What rain
does fall could be heavy with almost zero storm motion and PWATs
will still be above 1 inch.
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
The large scale pattern has a decidedly summertime look and feel
to it through the Memorial Day weekend and into next week with
light winds aloft and a prevailing ridge across the northeast
CONUS. Temperatures will average above normal with the core of the
`hot` weather front-loaded Friday-Sunday before trending modestly
toward late May/early June climatology. Precipitation risk early
in the period should be characterized by diurnal convection with
the highest probs occurring during peak afternoon heating,
augmented at times perhaps by weak disturbances drifting through
aloft. Max POP may be centered on or around Memorial Day as a weak
shortwave suppresses heights as it passes by to the north and some
interaction takes place with `tropical` system migrating toward
the southeast U.S. coast. Latest NHC forecast says this area of
disturbed weather has a 30% chance of cyclone formation in the
next 48 hours.
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
High pressure over the region will result in widespread vfr conds
and light winds this morning. Passage of an upper lvl
disturbance, combined with an increasingly moist ssw flow, will
produce sct shra/tsra during the aftn and early evening. Although
vfr conds will predominate, a brief vis reduction is possible
assoc with a passing shra/tsra.
Sct evening shra/tsra should taper off, as disturbance passes
east of the region this evening. Focus will then shift to the
potential of patchy late night fog in spots that happen to receive
rain this aftn/evening. A moist swrly flow ascending the mtns
could also result in ifr cigs at KBFD late tonight, as latest mdl
soundings and SREF prob data suggest.
Fri...Early am low cigs possible. Isold pm tsra impacts possible.
Sat-Mon...Isold pm tsra impacts possible.