Scientific Forecaster Discussion
fxus61 kctp 162344
Area forecast discussion
National Weather Service State College PA
644 PM EST Sat Nov 16 2019
a high pressure area to our north will set up shop across
northern New England and the Canadian Maritimes. A very light
wintry mix is possible Sunday night into Monday over far eastern
PA as a moderately strong area of low pressure moves up the
coast, but well off-shore. Near normal temperatures and
generally dry weather is expected for at least the first half of
the upcoming week.
Near term /through Sunday/...
mainly clear skies, very dry air and light wind will allow
temperatures to fall steadily tonight. Although a light
easterly breeze will likely keep readings from falling as far as
they could if surface high were directly over PA. A blend of
latest guidance supports lows ranging from the teens over much
of the forecast area and low 20s in the south. Given the
exceptionally low late day dewpoints, would not be surprised to
see single digits minimums in some of the perennial cold spots
across the northern tier.
Short term /Sunday night through 6 PM Sunday/...
model soundings make a good case for skies becoming mostly
cloudy Sunday across the eastern half of the state, the result
of an increasingly moist southeast flow overrunning dome of
cold air at the surface. The cloud cover and cold air damming
signature in the surface pressure fields support undercutting
nbm guidance. Have gone close to the superblend numbers with a
bit heavier weighting to the cooler NAM MOS.
The system deepening off the coast should move very little
through the day Sunday, and we will keep the fcst dry for the
Long term /Sunday night through Saturday/...
*not as cold but below-average temperature bias
*potential for light wintry mix off and on next week
Looking to the week ahead, expect temperatures to gradually
trend milder but with a below-normal bias. The latest long term
temperature outlooks favor below average readings through the
end of the month.
There remains some variability in the model guidance (low
confidence forecast) concerning the precipitation type and
occurrence next week.
Coastal storm off virgina CAPES deepens and moves north toward
Cape Cod. Precipitation on the west side moves into eastern
central PA. Some freezing rain is possible. Upper level trough
or low moves east across PA may trigger some snow showers
primarily over the mountain areas north and west. Need to
monitor the winter wx risk with potential travel impact to the
Monday morning commute.Probability of precipitation are only slight or chance and any
amounts are light. Temperatures warm on Monday making most areas
likely changing to rain.
Tuesday low pops due mainly to uncertainty as first storm exits
to east. Northern stream disturbance/upper level low or clipper moves
across PA Tuesday night into Wednesday bringing more chances
for rain and snow showers over the northwest. A brief period of
lake effect/upslope precipitation on the back end of this is
possible hence low pops continue. Next bigger system moves
across the Great Lakes Thursday and Friday. May start as a mix
Thursday morning and then switch over to rain. Thursday night
some snow may work in over the higher terrain in the North. Lake
effect is possible on the back side of this system by late
Aviation /00z Sunday through Thursday/...
VFR conditions will continue until at least Sunday night, even
for the southeast where high clouds come in tonight and lower clouds
spread overhead later Sunday. But, the clouds on Sunday should
also be VFR.
The wind has settled down a little, and should become a little
lighter overnight. Only jst seems like they could stay a little
stronger, and could have g15kt thru the overnight. The pressure
gradient does tighten slightly over the southeast (lns, mdt) Sunday.
That could increase their wind again after a night of light
The system off the East Coast should remain far enough away to
make no impact at all for most of the area. However, a few spits
of drizzle/light rain, or even a very light mix could impact
eastern PA late Sun night and Monday. However, the track of the
storm appears to be moving east with each new model cycle. An
upper trough pushing in from the Ohio Valley could touch off a
brief sh and some lake effect sh are possible Mon-tues.
Tue...sct shsn northwest.
Wed-Thu...no sig wx.