Scientific Forecaster Discussion
Area forecast discussion
National Weather Service State College PA
739 am EST Thursday Nov 26 2015
strong high pressure wedged from the central Appalachians to the
Canadian Maritimes will maintain dry weather with moderating
temperatures into Friday. A cold front will move across the state
Friday night into Saturday bringing the next chance of rain
Near term /until 6 PM this evening/...
broken high clouds now filtering into eastern/southeast PA early
this morning due to a weak shortwave embedded within the broad
upper flow. Only one patch of lower clouds in the central
mountains...but plenty of low-middle deck across the northwest half of the area.
This should continue to provide partly to at times mostly sunny
The strong surface high over the Canadian Maritimes and its associated
surface axis extending across eastern PA to the central Appalachians
will be the mainstay of the next 24 to 48 hours...keeping our
weather dry with moderating temperatures. Mixing will still be
limited across the east and especially northeast...where i'm
indicating maxes to hover around 50 today. Elsewhere...expect
50s...and a 60 could occur along the southern border.
Short term /6 PM this evening through 6 PM Friday/...
a mild night is in store across central PA...especially western
sections which should not decouple thanks to the persistent
southwest flow. Across the east...surface ridge axis anchored over
southeast PA will promote decoupling and another seasonably cool
night...with mins likely a few degrees milder than Thursday
morning. Ridge will show more signs of breaking down/giving way by
12z Friday as ribbon of high precipitable water banked from the Ohio Valley
through the eastern glaks responds by sagging southward. A general
increase in clouds from northwest to southeast will be seen at
that time and mins generally 5 to 8 degrees higher than Thursday
Slow moving frontal zone will sag towards northwest PA by late
Friday...introducing an increasing chance of showers to the
northwest mountains by evening. The remainder of central PA should
remain dry through nightfall...but likely probability of precipitation overspread the
northwest half of central PA later Friday night.
Long term /Friday night through Wednesday/...
broad southwesterly flow aloft will continue into late week across
the eastern half of the Continental U.S. Between upper an ridge extends northeastward
from the deep south into the Carolinas and a strong...digging upper
trough currently spinning over Nevada. A northern stream trough is forecast
to swing through the northestern Continental U.S. Over the weekend. Energy from the
western trough is forecast to eject eastward next week leading to a more
unsettled pattern across the east.
The northern steam trough will bring a cold front across the region
late Friday into Sat with the chance of showers...but significant
rainfall amounts are not likely. What is likely is a return to
more late November-like weather.
Latest mdm rain guidance continues to show that the front will
stall to the south of the region late in the weekend and slowly
works its way northward early next week as energy moves east from the
upper low. This type of pattern change is generally fraught with
increased forecast uncertainty...and this time is no exception.
At this time range have painted increased chance probability of precipitation for Monday
into Wednesday across the region. This includes the possibility of
a snow rain mix...mainly across northern sections. But at this
time...the possibility of significant storm development in the
long term period appears low.
Aviation /13z Thursday through Monday/...
main thing the next few hours is low level wind shear.
Some fog in the southeast.
An isolated lower cloud outside the office here
and ipt earlier.
Another hour or so...then we are looking at VFR
Did not hit the lower clouds or fog hard tonight.
This based on the winds becoming more SW. The
southeast may see some fog.
Have a good Thanksgiving.
Earlier discussion below.
Cold front drops northwest-southeast through the area Friday night and
Sat...bringing widespread light showers.
Thursday PM-Friday am...fog/low ceilings possible central-east. VFR elsewhere.
Friday PM-Sat...VFR/MVFR with rain showers.
Sun-Mon...mainly VFR - rain possible south.