Scientific Forecaster Discussion
fxus61 kpbz 121513
Area forecast discussion
National Weather Service Pittsburgh PA
1013 am EST Tue Nov 12 2019
periodic snow showers should continue today with an upper level
disturbance, before building high pressure returns dry weather
Near term /until 6 PM this evening/...
the main change was to expand the Winter Weather Advisory into
Lawrence PA and Columbiana Ohio for the afternoon. Radar trends/href
runs suggest another 2-3 inches in these counties, which seems
reasonable given cold advection, good northwest fetch off of Lake Erie and
steepening lapse rates. Would expect brief bouts of quick
accumulation with visibility below 1/2 mile at times in the heavier
snow showers. Another 1 to 2 inches can be expected generally north
of I-70. The ridge advisory zone can expect another 2-3 inches thanks
to upslope enhancement, with other locations from hlg on south and
west generally seeing an inch or less. 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 /15z 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
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.
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.
Maryland...Winter Weather Advisory until 7 PM EST this evening for mdz001.
Ohio...Winter Weather Advisory until 7 PM EST this evening for ohz041.
PA...Winter Weather Advisory until 7 PM EST this evening for paz007>009-