Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus61 kpbz 121021 
afdpbz

Area forecast discussion
National Weather Service Pittsburgh PA
521 am EST Tue Nov 12 2019

Synopsis...
periodic snow showers should continue today with an upper level
disturbance, before building high pressure returns dry weather
Wednesday.

&&

Near term /until 6 PM this evening/...
Post frontal snow should continue to taper off from west-east as low
pressure and its associated cold front moves east. Mesoanalysis also shows
upper divergence also shifting east, with a noticeable increase in
vsbys in the sfc obs.

Scattered to numerous snow showers are then expected to develop
through the day with the approach and passage of an upper trough.
North-northwest wind should also result in lake enhancement, with both a Lake
Erie and Huron connection. Steep lapse rates and instability in the
lower levels should also enhance any snow bands that become
organized. Maintained the Winter Weather Advisory as is for areas north
of I 80, and in the PA/WV/MD ridges where another 2 to 4 inches of
snow is likely. Elsewhere, an inch or two is expected for areas
affected by the numerous snow showers, with less than an inch across
much of Ohio and nrn WV. Little if any temperature recovery is expected
through the day in cold advection.

&&

Short term /6 PM this evening through Thursday night/...
snow showers should taper off tonight as the trough exits, sfc high
pressure begins to build in, and as the 850 mb heights become
anticyclonic. Dry weather should then continue through Wednesday
night as sfc high pressure moves east across the region.

Clouds should increase later Wednesday and Thursday in warm advection
ahead of an approaching trough. The clouds should decrease Thursday
night as the trough exits and sfc high pressure begins to build in.

Temperatures are expected to be 20 to 25 degrees below average
tonight and Wednesday, before moderating to around 10 degrees below
average by Thursday.

&&

Long term /Friday through Monday/...
sfc high pressure under broad upper troughing across the NE Continental U.S.
Should maintain dry weather and colder than average temperatures
through Saturday. Ridging between and ern Continental U.S. Trough, and a
midwestern trough, should then maintain dry and gradually warming
weather through early next week.

&&

Aviation /10z Tuesday through Saturday/...
IFR to LIFR conditions for the early part of the forecast as an area
of snow quickly moves through the region. All ports, with the
exception of mgw, will be snow to begin the forecast. Mgw will
quickly transition over within the first hour or so.

A break in the snow and an improvement to MVFR cigs is expected at
all ports as dawn approaches. Vis should improve as well, although
fkl may hold onto lower vis as snow showers begin to stream from Lake
Erie.

After Dawn Lake-enhanced snow showers will become the focus and may
bring periods of reduced visibility; however, confidence is too low
at the moment to pinpoint which sites and time-frame specifically.



Outlook...
with building high pressure Tuesday night into Wednesday, VFR
conditions shall return. Fkl may experience restriction until
Wednesday night if lake-enhanced snow showers prevail.

&&

Pbz watches/warnings/advisories...
Maryland...Winter Weather Advisory until 7 PM EST this evening for mdz001.
Ohio...none.
PA...Winter Weather Advisory until 7 PM EST this evening for paz007>009-
074-076.

National Weather Service Glossary of Abbreviations