Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
547 am EST Thursday Mar 5 2015
snow will diminish in coverage from northwest to southeast
today...with another night of near zero temperatures expected
Near term /until 6 PM this evening/...
with 545am update...have slightly raised probability of precipitation on the back edge of
the snow band...as radar returns have in fact filled back in
southwest of Pittsburgh. Made minor increase in snowfall over the
next few hours...but change was quite small. Previous discussion follows.
Back edge of snow is a bit ragged on radar...which has caused
some uncertainty as to just which locations may be done with snow
and where snow will continue. Line extending from DuBois to Butler
and New Philadelphia has likely seen most if not all of the snow
they will receive. Snow remains more intermittent from Indiana to
Pittsburgh into Zanesville. Models have consistently shown that
back edge of snow would move east during this time period then
ease back to the west for a few hours through sunrise...and have
kept this trend in forecast following the trend of the NAM/hrrr.
Radar returns remain quite healthy from Morgantown to
Uniontown...and moderate to heavy snow should still continue there
for several more hours. Still...an overall trend of diminishing
snowfall is expected through the day as drier air moves in from
the northwest. This is most noticeable with a current dewpoint of
3 at Franklin while dewpoints remain in the middle teens from DuBois
to Pittsburgh. No changes will be made to advisories/warnings at
this time. After mild weather yesterday...highs some 20 to 30
degrees below normal will return...as temperatures will rise
little during the day.
A lingering snow shower will be possible this evening in the higher
terrain of WV/MD...but expectation is that skies will become mostly
clear and winds should go calm with high pressure moving into the
region. Temperatures should plummet towards zero...especially with
many locations picking up a fresh layer of snow. This is expected
to set a few more records. With winds going calm...wind chill
values are not expected to be an issue.
Short term /6 PM this evening through Sunday/...
pattern will remain active. Although Friday will be dry...rounds of
precipitation are expected Saturday and Sunday. Neither system
appears to have much deep moisture to work with...so have kept
chance probability of precipitation to the north with diminishing chances for precipitation
farther to the south. Although highs will remain below normal...in
the 30s...temperatures should warm enough that some rain should be
able to mix in with snow from Pittsburgh to the south.
Long term /Sunday night through Wednesday/...
the extended period looks to be relatively quiet as zonal flow
sets up across the forecast area and we see a gradual warming
trend in temperatures...extending slightly above normal by
midweek. A shortwave will brush by to the north on Monday but with
limited moisture and weak dynamics...the best chance for any
precipitation will be mainly limited to locations along and north
of Interstate 80. Models show a similar setup by midweek...but
again expect minimal impacts as energy will be too far north.
Adjustments to the extended were based mainly on a blend of ec and
Aviation /12z Thursday through Monday/...
low MVFR and IFR conditions are expected to continue until middle
morning before starting to improve from north to south as high
pressure builds in the wake of the front.
Outlook.../Thursday night through Monday/...
restrictions are possible with a Sunday morning cold front.
Pittsburgh record low on Thursday March 5...8 set in 1926.
Morgantown record low on Thursday March 5...8 set in 1960.
Zanesville record low on Thursday March 5...2 set in 1978.
Pittsburgh record low on Friday March 6...2 set in 1901.
Morgantown record low on Friday March 6...12 set in
Zanesville record low on Friday March 6...5 set in 1960.
Maryland...Winter Storm Warning until 4 PM EST this afternoon for mdz001.
Ohio...Winter Weather Advisory until 4 PM EST this afternoon for
Winter Storm Warning until 4 PM EST this afternoon for ohz069.
PA...Winter Weather Advisory until 4 PM EST this afternoon for
Winter Storm Warning until 4 PM EST this afternoon for paz076.
WV...Winter Weather Advisory until 4 PM EST this afternoon for
Winter Storm Warning until 4 PM EST this afternoon for wvz012-