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FXUS61 KPBZ 172338
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
738 PM EDT Sun May 17 2026

.WHAT HAS CHANGED...
Forecast remains on track.

&&

.KEY MESSAGES...
1) Heat may impact sensitive populations early this week.

2) Severe storm chances increase into Tuesday and Wednesday.

&&

.DISCUSSION...
KEY MESSAGE 1...
Today and tomorrow will feature a building ridge. Satellite only
shows decaying clouds south of I-76, with the 12Z sounding only
alluding to chances of some fair weather cumulus, with perhaps
a shower/storm or two should the 700mb layer saturate and tap
into elevated instability. All in all, this suggests temperatures
should have no issue climbing today, with the hottest hours
from 2p-6p. HREF 50th percentile shows low-to-mid 80s for most,
with upper 70s in higher elevations and north of I-80. THE NBM
forecast was lowered to match this. Towards the high end of the
distribution, temperatures could climb into the upper 80s,
particularly for urbanized and/or valley locations.

Monday, and perhaps Tuesday, will likely be the hottest days of
the week. Monday, little cloud cover makes heat more likely,
while uncertainty increases Tuesday with uncertainties in
convective cloud coverage. A non-BC ensemble, like LREF, shows
high temperatures in the lower terrain south of I-80 could peak
in the upper 80s, with generally lower 80s favored for the high
terrain and north of I-80 (50th percentile). In the worst case
scenario, urbanized valley locations could break the 90F mark
for highs each day. The current forecast is within 3F of record
highs for Morgantown, New Philadelphia, Pittsburgh, and
Zanesville on May 18th. Correspondingly, record max lows will be
challenged Monday and Tuesday morning for most climate sites.

The NWS heat risk shows mostly a moderate risk Monday into
Tuesday, whereby heat may generally impact the most sensitive
populations. Make sure to stay hydrated or monitor for signs of
heat illness if spending excessive time outdoors.


KEY MESSAGE 2...
Monday will carry non-zero, conditional severe chances, mostly
for the high terrain. In the low probability event that ridge-
top convergence is enough to overcome ridging, DCAPE as high as
800 to 1000 may would be enough to pose a downburst wind
threat, though with flow aloft pushing northeast, any terrain-
inspired storms would likely flow out of the area, in the low
probability event they occur.

Tuesday has consistently shown the highest severe risk as the
ridge begins to breakdown. In this pattern, the highest chances
of any storms would come in a pre-frontal trough which
accelerates into a higher DCAPE environment, posing mostly
downburst wind threats within storms. CIPS, CSU ML, SPC, and
various other NCAR ML models generally spread the highest threat
over the northwestern half of the warning area (the portion of
the warm sector closest to the advancing mid-west cold front).

Most ensembles actually have the cold front across the middle
of the area Wednesday morning, so severe chances will mainly be
ahead of the front in the southeastern part of the area on
Wednesday, should the environment have enough time to
destabilize before moving through. This threat is more
conditional that Tuesday. CIPS, SPC, and ML agree that severe
chances Thursday and beyond remain quite low with the return of
cooler temperatures.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
The cumulus across the area has dissipated and only mid and
upper level clouds are present. Skies will continue to clear out
overnight as VFR conditions are expected through the period.
Winds will be light and variable through tonight. By tomorrow
after 15Z winds will ramp up again and gust up to 20 knots from
the southwest.

Outlook...
VFR is favored with dry conditions through Tuesday before an
approaching shortwave and surface low increases precipitation
chances (with lagging restriction impacts) Tuesday night into
Wednesday. VFR returns late Wednesday behind a frontal passage,
which shifts precipitation chances to our south where they
remain through at least Thursday.

&&

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

&&

$$

DISCUSSION...Milcarek
AVIATION...Shallenberger