Scientific Forecaster Discussion
fxus61 kctp 201356
Area forecast discussion
National Weather Service State College PA
956 am EDT Fri Sep 20 2019
anomalous upper level ridging will build east into the region
through the weekend. A cold front will likely push across the
area Monday, followed by high pressure building in from the
Great Lakes by the middle of next week.
Near term /through tonight/...
areas of valley fog should mostly dissipate by 15z, with another
day of abundant sunshine and fairly comfortable humidity,
although dewpoints will slowly rise through the 50s.
Precipitable water values will remain less than 0.60 inch for
the bulk of the area today...yielding nothing more than a few
spotty flat cu over the far northwest and perhaps the Laurel Highlands,
with just some patches of thin cirrus elsewhere.
Winds will be light and variable throughout the day with temps
rebounding to the mid and upper 70s for mid afternoon maxes.
The high temps will be a few to svrl deg f above normal.
Short term /Saturday through Sunday/...
no changes to the going forecast on Saturday as the strong
surface high slips southeast of the region. A return flow of
warmer southward flow will develop, and along with abundant
sunshine, temperatures should Jump Up to the mid to upper 70s
north to the lower 80s south/southeast.
A building upper level ridge and surface high off of the East
Coast will bring a resurgence of summertime warmth across the
area this weekend. Max temperature departures of +10-15 degrees
are expected Sat-sun with peak readings in the mid to upper 80s
in the southeast. Max temperatures would have to reach or rise above
90f to challenge daily records in most locations.
The biggest forecast question over the weekend appears to be in
regard to a shortwave trough that will move out of the Ohio
Valley and into the mid Atlantic region Saturday. This
shortwave should briefly flatten out the upper level ridge and
bring in some marginal instability.
Sfc-based CAPES will climb to between 1000-1500 j/kg in the
afternoon hours Saturday, and there will be some pockets of
slightly cooler mid- level temps of 5-6c over the west, while
the east should maintain 700 mb readings at or above 7c.
Will maintain a slight chance to chance of mainly showers for
the western mtns, but remove mention of any appreciable showers
east of a kelm to khgr line.
Heights and temps aloft will rise again on Sunday, leading to a
mostly sunny and pleasantly warm early autumn day with temps
well into the 70s across the northern and western mtns, and at
least the mid 80s in the southeast zones.
Long term /Sunday night through Thursday/...
the models are coming into agreement on the tracking of a cold
front that will move through the area Monday. This system will
likely be accompanied by a round of showers. It should move
through the region quickly with a return to fair and seasonable
weather appears likely Tue/Wed. High pressure should build
southeast from the grt lks mid next week.
Aviation /14z Friday through Tuesday/...
valley fog will give way to widespread VFR by 15z. Valley fog
will return late tonight with conditions at or below airfield
minimums most likely at kipt.
A spotty/isolated shower is possible mainly across the western
1/2 of the airspace Saturday PM. There is a better chance for
showers/storms Monday PM, ahead of an approaching cold front.
Sat-sun...am valley fog. Isold shra possible wrn 1/2 Saturday
Mon...sct showers/isold T-storms as a cold front crosses the
autumn officially arrives at 3:50 a.M. EDT, on Monday, sept. 23.