Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
822 PM EST Friday Mar 7 2014
the next chance for precipitation will come with a weak Saturday
night cold front.
Near term /until 6 am Saturday morning/...
although skies are currently clear...middle level clouds will begin
to move back into the region from the northwest by midnight. Made
another round of tweaks to hourly temperature trends...with
forecast appearing to be on track. Lows only dropping into the
upper 20s and lower 30s may be near climatology numbers...but it
has been nearly two weeks since an overnight low in Pittsburgh
remained in the 30s.
Short term /6 am Saturday morning through Monday/...
a weak cold front will sag over the area on Saturday. As prognosticated
dynamic spprt is lacking...probability of precipitation in the chance category were
maintained with the advance of the boundary...and with the trailing
shortwave on Saturday night. Given that lack of spprt...and lack of any
instabilty...wording for light precipitation was included...as was minimal
quantitative precipitation forecast.
In addition...warm advection in advance of the upper disturbance would
spprt rain initially...but change to snow is anticipated as
colder air drifts southward.
Cool high pressure will slither over the region on Sunday. But this brief
intrusion of cold air lakes to be short lived...with flow progression
resuming warm advection later on Sunday.
Long term /Monday night through Friday/...
long term will remains quiet until the middle of next week. Models
are still trying to figure out what to do with the interaction
between a cold front that crosses Tuesday night and low pressure
developing south of the front Wednesday. Ensembles and latest GFS seem
to be in okay agreement...showing the front and low well south of
the area. They are also indicating an open wave with only minor
intensification. At this time...the cold airs March southward will
be held at Bay as the surface low moves eastward through NC/VA.
This would mean rain showers over the south...snow showers north.
The heaviest precipitation would be south and east of the area closer to
the surface low.
Colder air will settle back in by the end of the long term.
Aviation /01z Saturday through Wednesday/...
VFR can be expected into Saturday with dry high pressure retaining
control of upper Ohio Valley weather. Light precipitation...and restriction
chances will increase Sat as a coldfront slides over the area. Genl
MVFR is anticipated as ceilings drop below 3kft.
Outlook.../Saturday night through Wednesday/...
VFR will rtn with decisive passage of the cold front early on Sunday. The
next chance for genl restrictions is expected with middle week low pressure.