Scientific Forecaster Discussion
Area forecast discussion
National Weather Service State College PA
207 am EDT Friday Oct 24 2014
weak high pressure will move in for Friday and Saturday. A
mainly-dry cold front will sweep across the region later on
Saturday. High pressure over the southeastern states will migrate
off the East Coast early next week. Another cold front should
impact the area around the middle of next week. Temperatures
should average near to above normal over the next 5 to 7 days.
Near term /until noon today/...
low stratus piling up on The Laurels and into western Warren Colorado.
The low clouds in the east do seem to be inching eastward just
ever so slightly. Dewpoints should be decreasing slightly with the
surface ridge starting to move in. However...the upslope flow lasts
through sunrise. Mins may be held up in the far west and east due
to the cloud cover. Sunlight and mixing should help the clouds to
mix away and the clouds in the east should move a bit quicker to
the east. Higher clouds are nearing and could dim the sun after
the expected clearing of the low clouds.
Short term /noon today through 6 PM Saturday/...
the deep layer cyclone offshore New England will weaken/open as
it continues to lift north-northeastward into Atlantic Canada by 12z Saturday.
This will allow high pressure to assume a more prominent role
influencing sensible weather trends for day 2. Expect improving
conditions overall with no rain...mix of sun and clouds during
the day and lower winds into Friday night. The main forecast issue
is probably with min temperature forecast with delicate balance between diurnal
or radiational cooling under surface ridge and increasing clouds out
ahead of shortwave digging southeastward across southern Ontario/upper
Great Lakes. The potential verification risk is likely to the
downside based on cons forecast which generally split the difference
between the warmer NAM/ec MOS and the colder GFS MOS. Upper level
energy tracking from Kentucky/WV through the Carolinas should have
little to no impact on the area.
Long term /Saturday night through Thursday/...
the long term period is overall quite tranquil for the middle of
autumn here in the NE U.S.
The main weather feature early on /Saturday-Sat night/ will be a
moderately strong...but dry upper short wave and surface trough moving
quickly east-southeast across the glakes region.
Mainly clear skies and relatively light wind Friday night and early
Saturday will transition to increasing clouds /and an increasing
westerly wind Sat afternoon and evening/ as the cfront
approaches. West to west-northwest winds Sat afternoon and night could gust
between 25-30 miles per hour at times.
Mentioned just low chance probability of precipitation for showers up north...with any
precipitation across central Penn being in the form of scattered sprinkles
late Sat afternoon and evening...from an anticipated several hour
period of broken-overcast middle clouds.
Aside from broken-overcast and relatively shallow strato cumulus across the northern
mountains Sunday with sprinkles and isolated showers...Sunday will be
dry and 5-7f cooler than the above normal temperatures in the middle 50s to
middle 60s on Saturday.
Sunday night through Tuesday will be dry and near to slightly
above normal in the temperature dept...as a ridge of high pressure at
the surface and aloft slides east across the middle Atlantic region.
Warmest temperatures in the week ahead will likely come Tuesday ahead of
the front with a moderately strong downslope westerly flow. High temperatures
in the 60s to around 70f Tuesday will be 10-15f above normal. Some
locations across the western and northern mountains may see high temperature
departures of nearly +20f.
The primary rain-maker /if we can even call it that/ comes during
the middle week as a cold front pushes east into the commonwealth...
beneath a weakening upper trough that will be shearing out to the
east-northeast across the glakes and southeastern Canada.
Quantitative precipitation forecast appears to be very light with this Tuesday night-Wednesday night
feature. Latest ensembles and 12z U.S./Euro operational models
point toward generally 0.10 of an inch or less.
A minor cool down and mainly dry conditions with just a slight chance
for showers appears likely for late next week under fast west-southwest flow
Aviation /06z Friday through Tuesday/...
main aviation concern early this morning will be the potential of
low ceilings at kbfd and kjst caused by moist upslope flow combined
with diurnal cooling of blyr. Satellite loop at 05z shows a band of
stratocu extending from Keri to kjst and NAM/rap output suggests this
plume of higher low level moisture will remain focused over the West
Mountains through dawn. Although kbfd is clear at 05z...model sounding indicate
the potential for a period of IFR conds there between 10z-12z.
Elsewhere...downsloping northwest flow east of the alleghenies should
ensure VFR conds across eastern PA this am despite a stratocu
deck around 4kft. At kunv and kaoo...can/T rule of a brief period of
MVFR ceilings around dawn.
Diurnal heating and resulting mixing of much drier air aloft
should cause any low clouds to break up between 12z-14z. The rest of
the day should feature a near certainty of widespread VFR conds
as high pressure ridge builds into the region from the west.
Sat-Tue...no sig weather expected.