PBZ issues Area Forecast Discussion (AFD) at Mar 24, 9:56 AM EDT484
FXUS61 KPBZ 241356
AFDPBZ
Area Forecast Discussion
National Weather Service Pittsburgh PA
956 AM EDT Mon Mar 24 2025
.SYNOPSIS...
Drier weather returns today with gusty winds and temperatures
increasing to slightly above normal. Throughout the week, the
current weather pattern will provide periodic chances for
precipitation, but overall, the week will be largely dry.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
KEY MESSAGES:
- Dry weather returns for most, but scattered showers possible
this afternoon north of I-80.
- Gusty winds, but just below advisory levels.
-------------------------------------------------------------------
In the wake of the cold front, clouds are beginning to exit as water
vapor imagery shows drier low and mid level air working in in
west to southwest flow which will lift the remaining lower
clouds out through the morning with lingering cirrus or perhaps
a few high-based cumulus in spots during the midday and
afternoon hours. An approaching upper trough north of Pittsburgh
will increase clouds again north of I-80 this afternoon, with
some scattered rain showers possible after 18Z or so, though
they will have to battle increasing dry air in the low levels as
dew points mix out some this afternoon despite southwest flow.
Winds will be notably gusty today with a strong pressure
gradient and deep mixing. Cold advection in the low levels will
steepen lapse rates and erode the weak inversion in place on the
12z sounding. Nearly all forecast soundings show the boundary
layer extending up close to 700mb by the afternoon, tapping into
stronger winds aloft. In general, guidance gives probabilities
of 100%/60%/5% for >30mph/>40mph/>45mph respectively (although a
few locally higher gusts are likely given the current synoptic
situation and deep mixing). Latest analogs support these max
values. Don't have the confidence that frequent advisory
criteria (46 mph) gusts will be reached, even in Eastern Tucker
County, so will continue mention in the HWO.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
KEY MESSAGES:
- Low PoPs north of I-80 tonight.
- Low-probability showers possible Tuesday into Wednesday,
mainly south of Pittsburgh.
- Temperatures remain seasonable Tuesday, cooler on Wednesday.
-------------------------------------------------------------------
Flow will veer more westerly tonight with upper trough arrival,
and moisture will increase north of Pittsburgh. This will allow
scattered rain and snow showers north of I-80. However, limited
moisture penetration into the DGZ and falling inversion heights
along with warm ground temperatures will keep accumulation and
snow rates to a minimum.
Upper troughing remains in place on Tuesday, with temperatures
remaining seasonable and a few degrees cooler than Monday. There
continues to be some uncertainty related to crossing waves and
possible precipitation Tuesday and Tuesday night. Global models
still align with the last few days' trends of keeping most
precipitation south of our area. However, as we come in range
of the CAMs, HREF nudges PoPs into our area south of the Mason-
Dixon, and the HRRR in particular has showers as far north as
I-80 with the weak surface low farther north across the
Virginias. Regardless, somewhere in between is likely the actual
solution, with light shower chances increasing south of
Pittsburgh Tuesday. A second wave will swing through late
Tuesday into early Wednesday. Given thermal profiles, this will
likely fall as a mix of rain and snow, with any light
accumulation limited to the ridges Tuesday night.
Continued, but decreasing chances for light rain and snow
showers is expected Wednesday as upper troughing lingers. Drier
weather is then likely by Wednesday evening as surface high
pressure begins to build. Continued cold advection in
northwesterly flow will keep temperatures a bit below-average on
Wednesday (highs in the 30s and 40s).
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
KEY MESSAGES:
- Brief dry period under high pressure through Thursday.
- Shower chances return for Friday and the weekend.
- Temperatures remain seasonable through midweek before a likely
warming trend.
------------------------------------------------------------------
Aforementioned surface high pressure should keep dry conditions
through Thursday. Daily precipitation chances then return for
Friday and the weekend, tied to uncertainty with shortwaves
rotating through the upper flow, although overall, precipitation
becomes more likely next weekend. Current expectation is that
most, if not all, of this potential precipitation would be in
the form of rain as opposed to snow.
While a return to, and then a rise above, seasonal norms is the most
likely outcome, the uncertainty regarding flow evolution is playing
havoc with ensemble temperature spreads towards next weekend. To
illustrate: at Pittsburgh on Saturday, the spread between the 10th
percentile max temperature (61 degrees) and the 90th percentile
temperature (85 degrees) reaches 24 degrees on the current NBM
run.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
Several TAF sites remain at VFR with a lingering stratocumulus
deck behind last night's cold front. Drier air working in on
southwest wind should lift ceilings to VFR through the morning,
with only cirrus and perhaps some isolated, high-based cumulus
during the afternoon. VFR is forecast through the afternoon and
the night with high confidence, save for perhaps FKL/DUJ, where
a rain or snow shower is possible during the afternoon into the
early evening, perhaps with a brief return of MVFR ceilings.
The main story today will be wind gusts. Deep mixing and a tight
surface pressure gradient will lead to increasing wind gusts
this morning, with frequent peaks of 25 to 35 knots from late
morning into early evening. Wind will slowly veer more towards a
westerly direction with time, with gusts slowly dropping off
during the evening and early overnight hours.
Outlook...
VFR is largely expected through mid week as the region
generally sits within the dry slot of a fairly stagnant upper
trough and some influence of surface high pressure to the
southwest. Embedded shortwaves within the upper trough pattern
may initiate low probability precipitation/restriction chances
that favor FKL/DUJ and the higher terrain, but model variability
remains high on these features.
A late week/weekend pattern shift to eastern CONUS ridging may
come with a transition period featuring increasing precipitation
and restriction chances.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...None.
WV...None.
&&
$$
SYNOPSIS...88
NEAR TERM...MLB/CL/88
SHORT TERM...Rackley
LONG TERM...Rackley/CL
AVIATION...CL/88
Source:
PBZ issues Area Forecast Discussion (AFD) at Mar 24, 9:56 AM EDT---------------
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