Area forecast discussion
National Weather Service Pittsburgh PA
346 am EDT Sat may 25 2013
Synopsis...
dry and cold weather can be expected for the weekend.
&&
Near term /through tonight/...
temperature drop over areas north and east of pit has been retarded this morning by
scattered to broken stratocu deck that has recovered since midngt. Nevertheless...some
locations have already reached the freezing mark and the rest continue o
flirt with the threshold. The remainder of the area counties are
in the middle 30s for the most part with dewpoints in the lower 30s.
Frost and freeze headline will thus be maintained until shortly after
daybreak.
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 /08z Saturday through Wednesday/...
patchy MVFR stratocu to the north of the PA Turnpike will quickly
dissipate after sunrise as drier air mixes down. Brief MVFR ceilings are
possible...with IFR at duj...through sunrise. 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.
Freeze warning until 8 am EDT this morning for mdz001.
Ohio...frost advisory until 8 am EDT this morning for ohz039>041-
048>050-057>059-068-069.
Frost advisory from 2 am to 8 am EDT Sunday for ohz040-041-050.
PA...frost advisory until 8 am EDT this morning for paz020-021-029-
031-073-075.
Frost advisory from 2 am to 8 am EDT Sunday for paz007-013-014-
020>023-029-073>076.
Freeze warning until 8 am EDT this morning for paz007>009-
013>016-022-023-074-076.
Freeze warning from 2 am to 8 am EDT Sunday for paz008-009-015-
016.
WV...frost advisory until 8 am EDT this morning for wvz001>004-012-
021-022.
Frost advisory from 2 am to 8 am EDT Sunday for wvz001-002-023-
041.
Freeze warning until 8 am EDT this morning for wvz023-041.
&&
$$
15/07
