Area forecast discussion
National Weather Service Pittsburgh PA
800 am EDT Sat may 25 2013
Synopsis...
dry and cold weather can be expected for the weekend.
&&
Near term /through tonight/...
with temperatures beginning to rebound have cancelled the
frost/freeze headlines for this morning. Only other adjustments
were made to diurnal temperature trends and sky cover through the
morning hours as stratus remains entrenched in the northern
counties and the ridges.
Previous discussion follows...
as Upper/Middle level trough axis has dug toward the coast...cold northwest flow over the
upper Ohio region...with high pressure on the surface...will maintain sub-average
temperatures today...which were forecast 10 to 15 degree undr using a blend of
already-close guidance.
Expect some high-based stratocu to form this afternoon as prognosticated
convective temperatures should be exceeded...but only scattered coverage is
anticipated given the forecast temperature/deep spreads.
The surface high pressure axis is expected to slide further eastward over the
area tonight. Another cold night is thus anticipated...but headlines
have been shifted eastward also...with a smaller freeze area limited to
the northern zones given prognosis of an ovrall warmer column. Day
shift may have to adjust as radiation conditions may spprt a more
expanded area...especially across the ridges.
&&
Short term /Sunday through Monday/...
high pressure undr northwest flow will maintain dry and cool conditions through
most of the short term period. A Great Lakes shortwave is expected to
reintiate warm advection by Monday...and temperatures were moderated closer
to the averages for that time frame.
&&
Long term /Monday night through Friday/...
models differ in depictions of a resumption of a warm advection regime
for Monday night and Tuesday with NAM being the more agressive in
terms of precipitation potential. As chance probability of precipitation were already included with
The Crossing of the warm front...have decided to persist despite
GFS and European model (ecmwf) dry solutions. However...have adjusted timing based on
these latest deterministic trends and have also diminished probability of precipitation
for the remainder of the week as per expectations of warm sector
domination undr an amplifying ridge.
Temperature recovery will be dramatic...with readings conservatively prognosticated
10 to 15 degrees above the seasonal averages for the latter half
of the week.
&&
Aviation /12z Saturday through Wednesday/...
patchy IFR in br/stratus has developed across the fkl/duj area...as well
as hlg. This should quickly end this morning as drier air aloft mixes
down. Otherwise mclr skies and northwest winds gusting to 20-25kt expd for today.
Outlook.../Saturday night through Wednesday/...
VFR conds expd with high pressure in ctrl through Monday. Shower/thunderstorm chances
return with a warm front Monday night into Wednesday.
&&
Pbz watches/warnings/advisories...
Maryland...frost advisory from 2 am to 8 am EDT Sunday for mdz001.
Ohio...frost advisory from 2 am to 8 am EDT Sunday for ohz040-041-050.
PA...freeze warning from 2 am to 8 am EDT Sunday for paz008-009-015-
016.
Frost advisory from 2 am to 8 am EDT Sunday for paz007-013-014-
020>023-029-073>076.
WV...frost advisory from 2 am to 8 am EDT Sunday for wvz001-002-023-
041.
&&
$$
