Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
408 am EDT Sat Mar 28 2015
dry conditions and well below normal temperatures will persist
through the weekend before the next weather disturbance impacts the
region Sunday night into Monday.
Near term /until 6 am Sunday/...
well below normal temperatures this morning will recover slightly
but not much as the axis of a deep longwave trough slowly
transitions over the area. Continued cold air advection out of the
northwest and cloud coverage largely in place until middle afternoon
will result in maximum temperatures around 25 degrees below normal on
average. There is a good chance we will see record low maximum temperatures
broken at some locations. Cloud coverage will scatter out by early
evening as surface high pressure continues to build in and lower levels
dry out...leaving mainly clear skies overnight. Lack of cloud
coverage and light winds overnight will allow for good radiational
cooling night and cold night in the middle to upper teens...close
but not quite hitting record values.
Short term /6 am Sunday through Monday night/...
Surface high will push east of the area on Sunday with temperatures
increasing roughly 30 degrees over the course of the day as winds
becoming southwesterly ahead of the next frontal system. Cloud
coverage will be minimal early on...increasing during the afternoon.
Dry conditions are expected throughout much of the day as moisture
will not begin to increase substantially until Sunday evening...with
rain spreading across the forecast area late Sunday night ahead of
the approaching cold front. Front will cross the region Monday
morning through early afternoon. Models remain in fairly good
agreement with this system in regards to timing and temperatures
aloft...still looking as though it will be warm enough to keep any
mention of snow to the north of pit and along the ridges. Still
looks like a high pop/low quantitative precipitation forecast scenario as the disturbance is prognosticated
to move relatively quick across the area...with precipitation largely
ending by early Monday evening.
Long term /Tuesday through Friday/...
quick compact system plows through the region on Tuesday. Increased
probability of precipitation a bit with this system...but would like to see more continuity
from models before increasing to likely probability of precipitation. High pressure will
briefly build into the region Tuesday night through Wednesday night
before next system approaches from the west. Although GFS/European model (ecmwf) both
show a front crossing the region Thursday night...models quickly
diverge by Friday. Have thrown out the fast GFS outlier and stuck
closer to European model (ecmwf) forecast which has ensemble support indicating the
front will likely hang up for another day. This could allow for a
prolonged period of rain across the region. Temperatures will be
near normal through the period...with thursdays values rising to as
high as 10 degrees above normal.
Aviation /08z Saturday through Wednesday/...
any widespread snow has come to an end...although a passing MVFR
snow shower cannot be ruled out. Model guidance through the
overnight hours so far has been more pessimistic than
observations...with VFR ceilings observed instead of MVFR ceilings in
models. However...MVFR ceilings could move in from the north through
sunrise. Winds will remain elevated through the afternoon
hours...with values decreasing after sunset as high pressure builds
in from the west.
Outlook.../Sunday through Wednesday/...
the next chance for widespread restrictions is expected with a
Sunday night frontal system. Another round of restrictions will be
possible on Tuesday.