Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
253 PM EST Thursday Jan 29 2015
a cold front will cross the area tonight...followed by building
high pressure Friday and Saturday. Low pressure may bring more
wintry weather Sunday.
Near term /until 6 am Friday morning/...
a cold front will move across the region this evening with addnl snow showers. Some
rain could mix in Erly this evening S of I 80. With Lake Erie mostly
frozen...only a limited connection off Lake Huron is expd mainly across
northwest PA. Favorable conds for upslope snow set up overnight with increasing moisture
in the snow growth region and northwest flow. Continued Winter Weather Advisory for the
ridges and northwest PA through Friday with several inches of snow expd. Temperatures
were forecast using a lamp/sref blend.
Short term /6 am Friday morning through Saturday/...
extended the Winter Weather Advisory through the day Friday for the
ridges...though with a Frozen Lake Erie will allow for the northwest PA
portion expire at Friday morning. Upslope snow showers should continue through the
day in the ridges before thinning moisture in the snow growth region and
lowering temperature inversions end the precipitation. A crossing upper trough should
allow for some scattered snow showers outside of this area as well.
Building high pressure should bring dry weather Friday night into Sat.
Below seasonal average temperatures were forecast using the latest sref numbers.
Long term /Saturday night through Thursday/...
models continue to joust in handling of low pressure projected toward the middle
Atlantic region from Saturday night into Monday. Persistence remains
prudent with latest GFS in genl line with current thinking outside
of timing issues. Meanwhile...European model (ecmwf) is forecasting a southward
track to surface slow center and precipitation shield. Both models continue to depict
an open middle level wave.
Bottom line is that an extended period of light...to moderate...but
accumulating snow is likely...with confidence building for areas
alng the Interstate 70 corridor.
Colder weather will follow as a series of shortwaves again dig an eastern
Continental U.S. Upper trough...details for which will be refined with time.
Aviation /20z Thursday through Tuesday/...
condition deterioration is underway and degradations can be
expected into Friday as mixed precipitation spreads over upper Ohio terminals
and changes to snow with cold front passage this evening. IFR can be
expected in snow showers this evening...and in widespread stratus which
will accompany the cold surge over the region.
Outlook.../Friday night through Tuesday/...
improvements can be expected as high pressure builds later on
Saturday...however...snow and restrictions are likely with Sunday
Maryland...Winter Weather Advisory until 7 PM EST Friday for mdz001.
PA...Winter Weather Advisory until 10 am EST Friday for paz007>009-
Winter Weather Advisory until 7 PM EST Friday for paz074-076.
WV...Winter Weather Advisory until 7 PM EST Friday for wvz023-041.