637
FXUS61 KPBZ 052258
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
658 PM EDT Sat Sep 5 2026

.WHAT HAS CHANGED...
No major changes made to the forecast into next week.

&&

.KEY MESSAGES...
1) Scattered showers and a few thunderstorms expected mainly
south of US-422 this afternoon into early evening. Severe
weather is not expected, but a few localized downpours are
possible.

2) High pressure and a drier air mass provides quiet weather and
seasonable temperatures through early next week. Then, a
warming trend precedes the next cold front, which may arrive by
Wednesday night.

&&

.DISCUSSION...
KEY MESSAGE 1...
Upper level low pressure will continue to spin near the Canadian
Maritimes through Labor Day, which will maintain a trough over
the northeast CONUS. Drier air will continue to filter in from
the north through the afternoon and night, with the CWA dropping
below 1.0 inch precipitable water values by 12Z Sunday.

Ahead of the dewpoint discontinuity, scattered showers and a few
thunderstorms are forecast to develop, mainly to the south of
US-422. Here, some breaks in the cloud cover should allow for
mixed-layer CAPE in the 500 to 1000 J/kg range. Although lapse
rates aloft are poor, updrafts may become tall enough for
lightning generation in some cases. The presence of 25-30 knots
of shear may allow for some loose storm organization as the
afternoon wears on, mainly south of I-70. However, the lack of
better instability and the weak lapse rates should largely
negate the threat of strong to severe storms. SPC agrees,
keeping the day 1 Marginal risk area to our south. PWAT values,
although dropping, do remain near or just above 1.5 inch for the
favored area, so downpours remain possible. Will have to watch
wet areas from the morning MCS, but only very isolated and
relatively minor water issues are anticipated right now.

The diurnal loss of instability will allow convection to largely
wrap up just after sunset. Another round of patchy fog is
possible by sunrise, especially in locations that received/will
receive rain.

KEY MESSAGE 2...
The remainder of the holiday weekend will provide a needed break
from the convective parade our region has seen lately. Surface
high pressure settling in from southeast Canada, with
northeasterly surface low. A good deal of sunshine is forecast
both Sunday and Labor Day, with temperatures remaining at
seasonable levels.

500mb heights rise after Monday as the northeast trough opens
and departs, and as central CONUS ridging begins to build across
the Ohio Valley. This will lead to a warming trend for Tuesday
and Wednesday, with continued dry weather. The next appreciable
chance for rain may arrive with a cold front during the
Wednesday night/Thursday period.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Continued southward movement of a surface cold front will end
showers within the region by 03z. Subsidence and dry advection
with generally light NNE wind fills in behind the boundary to
create high confidence VFR through the TAF period as any
additional clouds will generally be scattered CU Sunday.

HLG/MGW are the VFR exceptions due to the occurrence of rain
this afternoon and delay in surface drying; the clear skies plus
light enough wind may foster fog/low stratus between 08z-13z.

Outlook...
High pressure under cooler northwest to northerly flow aloft
strongly favors VFR through the early portion of next week. Any
additional restrictions would be tied to brief, pre-dawn river
valley fog.

&&

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

&&

$$

DISCUSSION...CL
AVIATION...Frazier