Scientific Forecaster Discussion
fxus61 kctp 201758
Area forecast discussion
National Weather Service State College PA
1258 PM EST Wed Nov 20 2019
high pressure will build in from the Ohio Valley today,
bringing mainly fair weather that will continue into Thursday.
Our next chance of rain will come later Thursday into Friday
associated with an approaching cold front. A new storm system
will move through the region Saturday and Saturday night,
followed by drier conditions with temperatures near to slightly
above normal to start the new work week.
Near term /through tonight/...
an upper low will slide east of the region today allowing a
drier northwest flow to develop over the County Warning Area.
Outside of the northern and western higher elevations where
clouds will remain stubborn within a northwest flow regime, early
clouds should generally give way to partly-mostly sunny skies.
Satellite imagery shows area of clearing moving slowly north.
With a brightening sky, afternoon highs should range from around
40 over the far north to near 50 in the lower Susquehanna
The overnight will be clear to partly cloudy in most areas, with
lows in the upper 20s to mid 30s.
Short term /Thursday/...
Thursday will be the transition day between high pressure passing
off to our southeast and a frontal system approaching from the west.
Clouds will be on the increase, but most of the region will
remain dry with the exception of the far northwest where a rain shower
may sneak in before the day is over.
Highs will vary from the mid 40s to lower 50s from north to S.
Long term /Thursday night through Tuesday/...
there is good consensus with a cold front racing through the
area early Friday. Latest model quantitative precipitation forecast points to an unremarkable
frontal passage with rainfall generally a tenth of an inch or less in most
The medium range guidance has changed a bit regarding the next
storm that previous model runs tried to scoot out south of the
region Saturday and Saturday night. The latest deterministic GFS
and European model (ecmwf) now take a well organized low up through western PA
Saturday night, before redeveloping a new storm over the mid
Atlantic states late at night and early Sunday. The 00z
Canadian still has this idea of a flat wave south of the state,
but that makes it the outlier. This has some implications with
ptype as the latest scenario would be warmer. At this juncture I
removed any mention of a wintry mix on the north side of the
low with just expectations of the usual locations seeing some
mainly light snow showers on the back side of the developing
After a chilly day on Sunday, temperatures look like they will
rebound heading into early next week.
Aviation /18z Wednesday through Monday/...
only a few remnants of lower cigs linger over the Laurel
mountains, specifically kjst and kaoo, while rest of taf sites
have moved into VFR ceilings as sunshine edges slowly northward
across central PA.
Winds from 300-320 degrees will increase to 8-12kt with gusts
15-20kts into the evening. Winds will decrease from west to
east tonight as high pressure slides east from the Ohio Valley.
Low cigs are mostly likely over the northern tier airspace
tonight into Thursday morning.
Thu...patchy am fog possible.
Fri...am low cigs west.
Sat...PM low cigs/rain likely. Chance of wintry mix Sat night.
Sun...low cigs/snow showers west.
Mon...residual low cigs west. VFR east.