012
FXUS61 KPBZ 191828
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
228 PM EDT Fri Jul 19 2024

.SYNOPSIS...
Dry weather is expected through Monday apart from shower chances
southeast of Pittsburgh Saturday. A wetter and more unsettled
pattern is favored for next week.

&&

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

- Mainly dry and less humid today

__________________________________________________________________

Apart from the low probability of orographically forced showers
in eastern Tucker County this evening, dry and seasonable
weather is expected to continue. Mostly clear skies are expected
to close out the day with high clouds encroaching from the
south along a transient shortwave.

Cloud cover and low-level warm advection will govern nocturnal
temperatures and fog. Areas southeast of Pittsburgh are more
likely to remain slightly above average with lower chances of
fog save in any patchy rain in eastern Tucker County. Northwest
of Pittsburgh, temperatures are more likely to fall below
average with patchy valley fog.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
KEY MESSAGES:

- Dry weather is expected through Monday, save shower and storm
  chances south and east of Pittsburgh Saturday.

_________________________________________________________________

The vorticity maximum embedded in southwest flow will encroach
the area early Saturday morning. Around 10kts to 20kts of
southwest flow in the 850mb layer will act to saturate and warm
the low levels. With daytime heating, this will come together
to allow convective temperatures to be reached in roughly 500
J/kg CAPE. Spotty showers and storms are expected in the ridges,
with chances dropping of to the northwest. Severe weather is not
expected. For Pittsburgh and points north and west, remnant dry
air is favored to keep the rain away. A low-probability camp of
NAM guidance has precipitation focused farther northwest and
shows much higher totals than other guidance with moisture
pooling and stagnant convection, but this solution remains an
outlier.

This surge of southwest flow will bring temperatures a few
degrees higher than the day prior, with a fairly sharp dew point
gradient setting up between the Pittsburgh and Morgantown area,
with more humidity favored for the latter.

The wave is expected to clear overnight and allow for radiative
cooling to drop temperatures near-normal. Fog is most likely for
locations that experienced rain the day prior and typical valley
locations. Seasonably warm temperatures and passing high clouds
with dry conditions are favored Sunday.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
KEY MESSAGES:

- Periodic shower and thunderstorm chances increase through the
  week
- Above average temperatures expected

________________________________________________________________

Model ensembles indicate a trough will deepen across the Central
CONUS early next week, before drifting eastward by mid to late
week. This trough should approach the Upper Ohio Valley region
by Thursday. Southwest flow ahead of this persistent trough
will result in warm, moist advection across the region.

A series of shortwaves embedded in the southwest flow, and
diurnal instability, will lead to periodic shower and
thunderstorm chances across the area. At this time, it appears
the more significant shortwave passages will be mid-week where
highest POPs are focused in the forecast. Uncertainty still
exists though in the exact timing and coverage of the rain.

Above average temperatures are expected through the period, with
increased humidity levels as well.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
VFR with dissipating patchy afternoon CU expected through the
TAF period. Low probability exists for river valley fog near
FKL/DUJ (around 30% for less than 3 mile), but dry air mixing
today should limit impact compared to prior night.

Weak shortwave movement may support Saturday morning to early
afternoon showers (low probability thunderstorms) along the WV
high terrain. Added mention of low end potential at MGW but more
likely result is increase in mid-level clouds decks.

.Outlook...
VFR is expected through the Monday under the influence of high
pressure. A series of shortwave troughs lifting NE from the
Tennessee River Valley will support increased shower/tstm
chances along with area restrictions mid-week.

&&

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

&&

$$

SYNOPSIS...Milcarek
NEAR TERM...Milcarek
SHORT TERM...Milcarek
LONG TERM...Milcarek/WM
AVIATION...Frazier