Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
911 PM EDT Thursday Mar 13 2014
warm air will surge over the region on Friday...but precipitation
chances will increase after dark as another cold front passes.
Near term /through Friday/...
late evening update for the near term period featured adjustments to temperatures
based on observation and incoming lamp guidance. Alterations were also
completed to Friday wind and gusts as gradient tightens in advance of
Otherwise...middle level clouds will stream over the area tonight as jet streak
surges alng the eastward drifting warm frontal zone. This warm advection
regime will spprt steady or slowly rising readings tonight...and the upward
surge for the Friday highs...forecast for which was based on the
aforementioned lamp guidance trend.
Short term /Friday night through Sunday/...
fast moving cold front and upper level trough will likely support
a period of rain showers Friday night that could end as scattered
snow showers across the far north. Behind the front...Saturday
temperatures are forecast back near the seasonal averages.
Cold advection with strengthening Great Lakes surface high will
maintain seasonably cool temperatures Saturday night into Sunday.
By Sunday afternoon...GFS and European model (ecmwf) project a southern stream low
pressure approach toward the Middle Atlantic States. That low may spread
a snow...or a rain...snow mix across areas south of pit. For
now...chance probability of precipitation were collaboratively entered for this scenario...with
a warming boundary layer to preclude serious accumulation outside of
the higher elevations.
Long term /Sunday night through Thursday/...
by Sunday night...appears enough cold air will be funneled southward
to change precipitation to all snow as the middle Atlantic low exits eastward.
Another upper trough is projected out of the Central Plains and
could bring a chance of rain or snow showers Wednesday and
Aviation /01z Friday through Tuesday/...
VFR can be expected until the apprch and passage of a cold front on
Outlook.../Friday night through Tuesday/...
the next chance of genl resrictions will come with northern flank precipitation of low
pressure crossing the middle Atlantic region on Sunday and Monday.