103
FXUS61 KPBZ 191343
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
943 AM EDT Sun May 19 2024

.SYNOPSIS...
High pressure will provide mainly dry weather and a warming
trend in temperatures through Tuesday. Showers and storms return
Wednesday through late week.

&&

.NEAR TERM /THROUGH TONIGHT/...
KEY MESSAGES:

- Mostly sunny this afternoon. Isolated showers possible on the
  ridges.
- Above-normal temperatures continue as a warming trend begins.
  _____________________________________________________________

The remaining fog/stratus will mix out by 11 AM, leading to a
mostly sunny sky CWA-wide under an upper ridge. Model cumulus
rule favors the ridges/areas east of Pittsburgh for afternoon
mainly scattered convective cloud development, and have shaded
the grids in that direction. CAMs are still advertising isolated
showers in the ridges, and this seems reasonable with expected
elevation-aided convergence. Added a very small PoP to these
areas. Afternoon high will climb into the low to mid 80s across
much of the area this afternoon, around 10 degrees above normal
for this time of year.

Mostly clear skies, light winds, and above-normal temperatures
continue straight through tonight with lows expected to remain
in the mid to upper 50s across the area.

&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
KEY MESSAGES:

- Dry weather can be expected through Monday night.
- Temperatures continue to climb to 10-15 degrees above normal.
  _____________________________________________________________

Dry weather is still forecast for the majority of the region
through Monday night as the upper ridge remains in place
overhead. Temperatures continue to warm as well, reaching the
mid to upper 80s during the afternoon, roughly 10-15 degrees
above normal for this time of year. Lows Monday night remain in
the 60s for most areas outside of the ridges, where mid to upper
50s remain likely.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
KEY MESSAGES:

- Dry and quite warm Tuesday.
- Rain chances return for Wednesday and Thursday, with some potential
  for strong thunderstorms.
- Seasonable temperatures and lower rain chances are expected Friday
  and Saturday.
____________________________________________________________

Dry weather prevails through Tuesday night as the upper ridge
slowly works its way off of the Atlantic Seaboard. A very weak
shortwave moving through its northwest periphery traverses the
lower Great Lakes Tuesday afternoon and could bring just enough
lift to support a few isolated showers and storms across NW PA
and NE OH. This is reflected in the forecast with low-end PoPs
(~20%) primarily north of I-80 and across our northernmost tier
of Ohio counties. The bigger impact on Tuesday will be
temperatures, with plenty of sunshine and dry antecedent
conditions pushing values further into the upper 80s and
potentially closing in on 90 degrees in some areas. Ensemble
probabilities for highs on Tuesday reaching 90+ degrees are >50%
in river valleys and urban areas at this time. It`s not out of
the question for some of the "cooler" daily records (86 at DUJ,
91 at PHD, and 92 at PIT/MGW) to be within reach.

While models continue to show some minor differences with the
strength and timing of a series of troughs ejecting from the
central Rockies across the Plains during the middle part of the
week, the larger overall signal generally favors a deepening
upper low over the Upper Great Lakes Wednesday morning and a
second shortwave trough subsequently rotating around its
southern periphery and across the lower Great Lakes Wednesday
night into Thursday. The result of this pattern is increasing
chances for showers and thunderstorms both Wednesday and
Thursday across the local area, with the highest probabilities
(currently 50-70%) coincident with the latter shortwave timing
Wednesday night and Thursday morning. We will continue to watch
for the potential for severe weather with this system, as
CIPS/CSU severe guidance continues to show some potential,
particularly on Wednesday. Temperatures on Wednesday, while
still expected to run above normal, may be knocked down a few
degrees compared to Tuesday due to the increasing cloud cover
and coverage in showers and storms.

Model divergence increases as we look beyond the cold front
passage on Thursday, but it does appear that the passage of
additional weak shortwaves may provide lower-end chances
(20-40%) for rain straight through the weekend, with
temperatures returning closer to climatology during that time.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
Lingering IFR fog restrictions remain at a few sites (HLG, AGC,
ZZV) this morning with river valley fog showing quite nicely on
satellite imagery. FKL/DUJ have seen low level moisture
manifest as stratus and are still stuck in LIFR to IFR CIGs.
Expect these restrictions to improve within the next couple
hours and by 14z or shortly thereafter all sites will return to
VFR and remain there with high confidence through today with
mostly clear skies and light to calm winds under high pressure.

Patchy fog remains possible (40-60% chance) Sunday night once
again, but mainly after 06Z and east of Pittsburgh.

.Outlook...
VFR and dry weather with high confidence are expected Monday
and Tuesday under the influence of high pressure. Precipitation
chances and associated restrictions return Wednesday with the
passage of a cold front.

&&

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

&&

$$

SYNOPSIS...Cermak/CL
NEAR TERM...CL/Cermak
SHORT TERM...Cermak/CL
LONG TERM...Cermak/CL
AVIATION...MLB/Milcarek