Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
544 am EST sun Jan 25 2015
low pressure will bring widespread snow later today through
Near term /through tonight/...
Erly morning updt to tweak temperatures based on latest observation/lamp data. A weak
shortwave across Lake Erie will continue to bring some light snow/flurries to
the region this morning.
Attention then turns to a deepening shortwave moving out of the middle
west and western Great Lakes region. This shortwave will advance across our region later
tday spreading snow across the region. Critical thicknesses and model
sounding profiles indicate the precipitation may mix with or change to rain near
and S of the southern PA border this afternoon into this evening..cutting down
on snow totals.
Models continue to open the middle level wave as it advns across eastern Ohio into PA
as the transition to a coastal low takes place. Moisture and Omega
fields still indicate a band of moderate snow will likely develop across
areas from zzv to pit to lbe this evening into the overnight hours before the
middle level wave opens lt tonight. With model trends showing a slight northward
push to the precipitation...decided to expand the Winter Weather Advisory further
northward into northwest PA.
Forecast was based on a sref/model blend to smooth out differences...
combined with surrounding weather forecast office and wpc coordination.
Short term /Monday through Wednesday/...
snow is expd to continue through Monday and Monday evening as the shortwave continues its
track across the area. Advisory level snow totals of 4-6 inches are expd from
near zzv to pit to lbe...with somewhat lesser amts north of I 80 and
areas well S of pit.
Broad upper trofg is prognosticated to begin to shift east of the region Tuesday with
decreasing snow shower chances. Building high pressure Wednesday should bring dry weather.
Below seasonal average temperatures were forecast based on the latest sref numbers.
Long term /Wednesday night through Saturday/...
fast moving clipper system will bring another round of snow
Thursday into Thursday night with a wintry mix possible along and
south of I-70. Bumped up probability of precipitation to likely for this system. Upper
level trough will remain in place into next weekend with well
below normal temperatures. Some important timing differences for
next weekend with next clipper and delivery of even colder Arctic
air into the upper oho valley. Wpc forecasts looks to be a good
compromise with a chance of snow showers later Saturday through
Aviation /12z Sunday through Thursday/...
low MVFR patches of IFR ceilings across the ports and this looks to
remain into midday Sunday. Fast moving shortwave and surface low
will push into region this afternoon with snow beginning midday
and becoming IFR to low IFR through Sunday night. Rain looks to
mix in for a time this afternoon and early evening at kmgw and
possibly kzzv before turning changing to all snow.
Outlook.../Monday through Thursday/...
restrictions in snow expected to continue Monday. Next widespread
restrictions Thursday with a clipper system.
Maryland...Winter Weather Advisory from 1 PM this afternoon to 1 PM EST
Monday for mdz001.
Ohio...Winter Weather Advisory from 1 PM this afternoon to 1 PM EST
Monday for ohz039>041-048>050-057>059-068-069.
PA...Winter Weather Advisory from 1 PM this afternoon to 1 PM EST
Monday for paz007>009-013>016-020>023-029-031-073>076.
WV...Winter Weather Advisory from 1 PM this afternoon to 1 PM EST
Monday for wvz001>004-012-021>023-041.