PBZ issues Area Forecast Discussion (AFD) at Apr 10, 8:10 AM EDT859
FXUS61 KPBZ 101210
AFDPBZ
Area Forecast Discussion
National Weather Service Pittsburgh PA
810 AM EDT Thu Apr 10 2025
.SYNOPSIS...
Rain with some snow mixed in will continue through dawn before
changing to all rain. Temperatures rise through Monday with dry
weather, until another frontal passage is possible early- to-
mid week.
&&
.NEAR TERM /THROUGH TONIGHT/...
KEY MESSAGES:
- Rain increases across the area today.
- The potential for rotating showers this afternoon.
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The warm front now placed to the south of the forecast area in
the middle Appalachian Range will begin to lift north as the low
center out over the lower OH Valley moves east. The surface
temperatures to the north are still in the mid 30s but will soon
wetbulb a bit more as temps lower. Thus will see some snow
accumulate along grassy areas and elevated surfaces. There will
be the potential for some snow on overpasses and bridges.
However, the probability for even a half od an inch is around
20% and unlikely to occur.
Heading into the coming day, the warm front and adjacent cold
front pull through, rain will be most likely in the mid-morning
and early afternoon, before the cold-core low settles in for the
afternoon period in the upper Ohio Valley. There is some
uncertainty whether precipitation ends, or if there will be
enough instability under the upper low to increase shower
chances into the evening. Should the precipitation turn more
showery, dependent on instability, there is the potential for
cold air funnels in any shallow updrafts tomorrow. The latest
models indicate that there will be a bit more instability than
previously thought. This is in conjunction with the potential
shear in place. What is also most notable heading into this
afternoon is the fact that 0-1KM CAPE is not crossing the 100
J/Kg mark. This has the potential to see some rotating showers
this afternoon and the potential for weak rotating updrafts.
Will mention this to the oncoming shift and perhaps will put
this potential in the HWO. The one caveat here is the fact that
these parameters only started to light up in the last 4 to 5
runs of the HRRR. This will continue to need to be monitored.
This environment persists into the overnight, though with the
loss of a heating component from the surface, the funnel threat
may end, though scattered showers may remain possible under the
destabilizing, cold-core low.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
KEY MESSAGES:
- Rain chances linger through Saturday.
- Wrap around snow possible Saturday in the highest terrain.
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A reinforcing shortwave is expected to dig into the upper-
Midwest, rounding the trough, and forcing secondary low
development in the southern Appalachians. This mid-level forcing
may briefly make for a secondary closed low, before an
elongated area of closed flow develops along the east coast.
This will, in turn, bring the surface low up along its eastern
flank, overspreading rain from Georgia to Maine.
In the current forecast, the main low track utilizing the best
moisture and forcing is to the east of the Appalachians. Here,
the potential for some spots in the forecast area to receive an
inch or more is more confined to central PA but there are a few
10% indications in the Laurels. However, the chance is remote
at best given the ensembles have locked in on a low track
keeping the heaviest precipitation to the east.
Some snow is again possible in the highest terrain Saturday with
cold air wrapping around the backside of the low. Since most of
this is forecast during the day with marginal freezing
temperatures, no impacts are expected, pockets of eastern Tucker
could see more than 1" if the snow rates remain high enough
with orographic enhancement.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
KEY MESSAGES:
- Uncertainty in early-to-mid week cold frontal passage.
-------------------------------------------------------------------
Ensemble clustering is much more confident in the upper low
departure late Saturday into Sunday with ridging through Sunday
and Monday, which will warm temperatures back up to near/above
normal. By late Monday, the next trough is forecast to pass,
though there is timing uncertainty with the trough and adjacent
cold front, which would allow the next chances of rain and a
cool down. By Tuesday at 8pm, roughly 60% of the ensemble
guidance has eastern troughing behind a cold front, and 40% has
a continued ridge. Should the trough pass, there is also
uncertainty as to the strength of the trough and cold.
By Wednesday and into late next week, uncertainty decreases yet
again with almost all ensembles and clusters showing that the
trough has passed, with building ridging yet again.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
Widespread light rain (some snow continuing to mix in at
FKL/DUJ for the next hour or two) and VFR/MVFR conditions are
ongoing to start the TAF period as a weak warm front pushes
through the area. Expect the widespread rain to begin tapering
off from west to east with the passage of the warm front,
roughly after 15z at ZZV, 18z at PIT, and 21z at LBE.
Precipitation becomes more showery this afternoon and evening,
with ceilings continuing to lower to widespread MVFR and then
IFR as upper level troughing settles in.
IFR ceilings and rain showers continue overnight. There will be
some fog potential as well, particularly outside of showers
where the ground (and near-surface environment) will be
saturated and winds calm. Latest ensemble guidance suggests
30-40% probabilities for IFR or lower visibilities after 06z,
with the greatest focus along and east of the I-79 corridor.
Outlook...
Restrictions are likely to continue, along with rain and snow
showers, Friday through Saturday night as an upper low drifts
across the region. VFR returns Sunday under high pressure.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...None.
WV...None.
&&
$$
SYNOPSIS...Shallenberger
NEAR TERM...Shallenberger
SHORT TERM...Shallenberger
LONG TERM...Shallenberger
AVIATION...Cermak/Rackley
Source:
PBZ issues Area Forecast Discussion (AFD) at Apr 10, 8:10 AM EDT---------------
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