Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 04/22/23

Area Forecast Discussion

National Weather Service Pittsburgh PA

 927 PM EDT Fri Apr 21 2023

.SYNOPSIS...
Shower chances will increase through the night with the
approach and passage of a cold front. Periodic showers favoring
northwest Pennsylvania along with seasonably cool temperature
can be expected into early next week before dry weather returns.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Update-Made a few minor adjustments to the overnight forecast
based on observations and near term model data.

Recent meso analysis, ACARS soundings, and 00Z observed
soundings indicate the limited instability has diminished across
the region. Removed thunder from the forecast, and the marginal
severe mention from the Hazardous Weather Outlook.

Showers are expected to increase, mainly after midnight, as
developing surface low pressure tracks north along a stalled
surface front currently analyzed across NW PA to SE OH. Jet
driven ascent/divergence aloft and positive vorticity advection
should also enhance the rain chance overnight. The surface low
is progged to reach western PA by early Saturday morning, and
will then pull the front through as a cold front as it tracks
further northeast.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
Showers are expected to traverse east Saturday morning in
connection with the previously mentioned shortwave and greater
traction of the surface cold front. By the afternoon, shower
activity will become more isolated with dry, cold advection
occurring behind the front but continued jet ascent with the
nearby positioning of the upper trough axis. Temperature will
generally peak during the morning hours ahead of the boundary
before gradually falling in the afternoon with said cold
advection.

Broad upper troughing will develop Saturday night into Sunday as
surface high pressure begins to build in from the west.
Additional shortwave passage Sunday afternoon and its associated
reinforcing weak front will aid additional scattered shower
activity focused mainly over northwest PA.

Cloud cover and a mixed boundary layer should limit the for
frost/freeze impacts Saturday night into Sunday. However,
greater cold air will be in place Sunday night into Monday that,
if wind is more lax and more cloud clearing occurs, offers a
higher probability for impact and potential for future hazard
highlights.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Ensembles indicate a high probability for continued broad
troughing over the Great Lakes region Monday through much of
next week. Perturbations moving through that flow may be enough
to spark periodic precipitation chances favoring locations north
of Pittsburgh. Otherwise, high pressure and subsidence between
the northern/southern jet streams should offer multiple dry days
with temperature slightly below seasonal averages.

&&

.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
Showers are expected to increase in coverage tonight as
deepening surface low pressure tracks northward along a cold
front across the Upper Ohio Valley region. Deterioration to MVFR
is expected as upper support and ascent increase on the northern
side of the low. Some improvement is likely after this initial
wave crosses for ports S and E of DUJ to FKL to ZZV, with
MVFR/patchy IFR elsewhere.

More widespread MVFR, with patchy IFR, is expected Saturday as
the low crosses the region. MVFR and scattered showers are then
expected through the afternoon as another upper level
disturbance crosses.

.OUTLOOK...
Patchy cig restrictions are possible Sunday and Monday under an
upper trough. General VFR returns under high pressure Tuesday
and Wednesday.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...None.
WV...None.

&&

$$
SYNOPSIS...WM/Frazier
NEAR TERM...WM
SHORT TERM...Frazier
LONG TERM...Frazier
AVIATION...WM