PBZ issues Area Forecast Discussion (AFD) at May 31, 1:46 PM EDT450
FXUS61 KPBZ 311746
AFDPBZ
Area Forecast Discussion
National Weather Service Pittsburgh PA
146 PM EDT Sat May 31 2025
.SYNOPSIS...
Behind a cold front, scattered light rain showers and cooler
temperatures can be expected this afternoon. Precipitation ends
this evening, and wind gusts also subside. Dry weather and
rapidly rising temperature will follow through early next week,
as high temperature hits above normal readings by Tuesday.
&&
.NEAR TERM /THROUGH TONIGHT/...
KEY MESSAGES:
- Thunderstorm chances end as the cold front exits by mid-
afternoon.
- Gusty NW wind of 25-35 MPH eases this evening.
- Low temperatures 10 to 15 degrees below normal, with frost
potential in eastern Tucker County.
-------------------------------------------------------------------
The cold front has sunk south of the Mason-Dixon Line, with only
a few showers and thunderstorms remaining along it in northern
West Virginia. The environment over the next hour does not
appear too conducive for strong to severe storms, with
diminishing surface-based CAPE and increasing dry air aloft,
which is helping to limit updraft strength. Behind the front,
cold advection in northwest flow and upper troughing are
supporting some generally light rain showers/sprinkles
underneath a stratocumulus deck. Temperatures are struggling to
remain in the 50s, and have even fallen into the 40s northwest
of Pittsburgh, while ZZV/MGW, where cold advection is just
starting to kick in, remain around 60. With steeper low-level
lapse rates, northwest wind gusts of 25 to 35 MPH continue this
afternoon.
Expect a drying trend to take hold by the late afternoon/evening
as increasing dry advection and subsidence will bring an end to
most precipitation by sunset. Clouds will also show a decreasing
trend, with a mostly clear sky by the overnight hours.
Stabilizing low levels will allow wind gusts to taper this
evening, with light wind overnight. The combination of light
wind and decreasing clouds will lead to overnight lows some 10
to 15 degrees below normal. With eastern Tucker County expected
to drop into the mid 30s, and with winds becoming light enough
at least in sheltered locations, a Frost Advisory was issued for
the overnight period.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
KEY MESSAGES:
- Warming trend with predominantly dry weather.
- Showers late Monday couldn't be ruled out northeast of
Pittsburgh.
-------------------------------------------------------------------
The short term flow patter remains high confidence. A eastern
trough will be replaced with ridging, clearing skies Sunday and
leading to a temperature rebound. Heating under subsidence will
lead to well mixed surface profiles, with potentially a weak
subsidence inversion overhead. With clear skies and tapping into
this layer, opted to raise temperatures a couple degrees over
guidance during the day, and lower dew points a hair. This may
still result in below normal temperatures, but the air may feel
quite dry.
Into Sunday night, clear skies are expected to prevail with a
relaxation in winds which may lead to temperatures ending up
near frost criteria north of Pittsburgh with efficient
radiative cooling. NBM probs remain <10%, but temperatures tend
to underpreform in valleys and sheltered areas when all frost
indicators are favorable.
Monday will see continued ridging and a return to near normal
temperatures, though there is some indication smoke aloft may
return which could stave a couple of degrees off highs. With
lower dew points, more dry surface conditions are forecast. A
subset of ensemble members have a fast weak wave northeast of
Pittsburgh which may result in a low probability of cloud cover
and perhaps a quick rain shower, but with surface profiles so
dry, there is also the chance that even with forcing, that
precipitation will not make it to the ground. Stuck with NBM
PoPs for now. Frost concerns are null Monday night with dew
point rises keeping lows well above the 30s necessary for
formation.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
KEY MESSAGES:
- Warm temperatures this week with moderate heat risk by
Wednesday and Thursday.
- Rain and severe chances again late-week.
-------------------------------------------------------------------
Continued ridging is forecast with high confidence. Ensemble
clusters have very little variability around the Pittsburgh
area, with height maxes around 588 dm Late Tuesday into
Wednesday. This would generally translate to a forecast in the
upper 80s for daytime highs. Modeling these ridging patterns in
the east typically come with some issues modeling the extend of
cloud cover and maybe daytime convection; add on there may the
the influence of smoke aloft during this period. This will
create some lower probability "cooler solutions" of low 80s
Tuesday/Thursday with mid-80s Wednesday.
The more high probability scenario is mostly clear and dry
weather under ridging, pushing daytime highs into the mid-to-
upper 80s for this period, with Wednesday likely the warmest
day. Chances of >80F all three days are 80% to 100% apart for
the ridges, and chances of >90F are ~50% for Pittsburgh and
river valleys Wednesday and Thursday, and as high at 80% for the
Ohio River Valley along the Ohio/WV border. Urban effects may
increase these probabilities locally. Combine this with
overnight lows only getting to the upper 60s to low 70s, heat
risk increases to moderate levels Wednesday and Thursday.
Confidence in the forecast is higher Wednesday than Thursday
with some cloud and precipitation timing uncertainty with the
next disturbance.
Precipitation spread is the highest Thursday and Friday,
indicating some subtle differences in timing the next rain
chances. Some severe chances come with this wave, as evidenced
in a 5% to 15% chance within 25miles on the CSU-MLP product.
Chances of rain >1" are low (around 15%) for now, though likely
a tad low due to the aforementioned timing uncertainty. This
should bring some relief, height falls, and a return to more
quasi-zonal flow, with most of the temperature spread next
weekend encompassed in the 70s for highs.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
Northwest flow stratocumulus behind a departing cold front
continue to generate spotty MVFR ceilings, with some IFR
lingering north of I-80, particularly at FKL. Light rain
showers/drizzle are also being seen in the troughing pattern
behind the front. The thunderstorm threat has ended at TAF sites
with the departure of the front. Wind gusts of 20 to 30 knots
will continue into this evening before diurnal stabilization
leads to diminishing peaks.
Past 00Z, dry advection and increasing subsidence with
approaching surface high pressure will end any lingering
precipitation, and also allow for a decreasing trend in cloud
cover. This will lead to areawide VFR conditions overnight.
Cannot totally rule out patchy fog in areas that have received
rain lately, but dry advection may mitigate this outcome.
Outlook...
VFR will continue Sunday under the influence of high pressure
and dry advection. These conditions are likely to persist under
ridge building to start the next week.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...None.
WV...Frost Advisory from 1 AM to 8 AM EDT Sunday for WVZ514.
&&
$$
SYNOPSIS...Frazier
NEAR TERM...CL
SHORT TERM...Milcarek
LONG TERM...Milcarek
AVIATION...Frazier/CL
Source:
PBZ issues Area Forecast Discussion (AFD) at May 31, 1:46 PM EDT---------------
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