Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
141 PM EST sun Nov 29 2015
weak high pressure will bring partial clearing near and north of I
70 through tonight before low pressure returns unsettled weather
late Monday and will continue into the middle of the week.
Near term /until 6 PM this evening/...
weak surface ridging and dry advection should continue to bring a
slow clearing trend north of the PA/WV/MD border today. Low stratus
and patchy light rain/drizzle should continue to the south as a
weak surface wave moves east along a cold front. Near seasonal average
temperatures are expected using a downward adjusted guidance
Short term /6 PM this evening through Tuesday/...
models are now showing a slower progression of the next system as
a weak ridge develops over the area Monday in reaction to the
deepening low over the central US. Have pushed back probability of precipitation
considerably on Monday...but will continue with previous forecasts
of increasing cloud cover.
Rain shield will overspread the area sometime Monday night...
depending on model depiction...and pick up in intensity Tuesday.
Strengthening low level jet and impressive moisture convergence
will lead to a good shot at a descent soaking later Tuesday
morning and into the afternoon. Best convergence will generally be
over the eastern half of the region...so would think this area
would be the focus of higher rainfall amounts.
Showers will begin to taper off slowly from west to east late
Tuesday as the occluded front...associated with the large stacked
system over the northern Great Lakes...swings through.
Expect another warm up Tuesday as strong warm air advection will
be ongoing ahead of the surface boundary.
Long term /Tuesday night through Saturday/...
the aforementioned front is currently timed for a Tuesday night
passage. The forecast thus features diminished probability of precipitation...although
chance numbers were maintained under The Crossing upper low. Dry
weather is expected for the close of the with high pressure
projected to rebuild.
The fading probability of precipitation and near-average temperature forecast were constructed
using the guidance blend.
Aviation /18z Sunday through Friday/...
MVFR ceilings continue today from about I-70 and south as low level
clouds and moisture are slowly erroding away. Expect clouds to
slowly break even in southern areas. Near Mason/Dixon line
locations like mgw...where low clouds will hold past sunset there
may be a period of some fog later as skies clear until dry air
works in. Light NE winds are expected through the period.
Outlook...Monday through Thursday/...
low pressure will return restriction chances late Monday through