Area Forecast Discussion
Issued by NWS Pittsburgh, PA

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FXUS61 KPBZ 241649
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
1249 PM EDT Sun Mar 24 2024

.SYNOPSIS...
Dry, quiet weather is expected today into tomorrow under high
pressure. Rain chances return early Tuesday for eastern Ohio,
late morning for western Pennsylvania as a disturbance tracks
into the region from the west.

&&

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

- Sunny, dry conditions are expected today under high pressure.
- Relative humidity this afternoon will range from 20% to 30%
  with mixing of dry air aloft. Wind gusts will be less than
  20mph. Therefore, fire weather potential is low.
- Temperatures will continue to trend below average despite
  sunshine with linger cool air aloft.

-------------------------------------------------------------------

The Ohio River Valley continues to feel the impacts from a
lingering upper-lvl trough exiting over the East Coast.
Currently, colder than normal temperatures aloft are mixing to
the surface and will impact afternoon high temperatures. With
this latest forecast update, widespread adjustments down were
made to the MaxT by 2-3 degrees despite prolong sunshine
throughout the day. Therefore, the high temperature across the
region will be 5 degrees cooler than the climatological average.

Along with cooler temperatures, very dry conditions are likely well
into the afternoon. On the 12Z PIT sounding a deep dry air mass
is noted at 1,800ft to 5,700ft; dew point values range from
-16F to -44F. Therefore, relative humidity values will drop to
 20% to 30% across the region with diurnal mixing. The lowest
 values will be spread across northern West Virginia and eastern
 Ohio. However, with the probability of wind gusts exceeding
 20mph below 10%, the potential for fire weather conditions is
 low.

&&

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

- Dry conditions and continued warming on Monday.
- Warmer yet on Tuesday with rain chances returning.

-------------------------------------------------------------------

Eastern ridge will shift toward the east coast Monday morning.
Deep surface high will move over northern New England and a
deepening 500mb low will move over the central US. The area
should remain dry Monday with just increasing high cirrus
clouds. As the surface high sits over northern New England, and
the system moves toward the Midwest, the surface pressure
gradient over the region will tighten. This setup will
strengthen surface winds, with gusts of 20 to 25 mph possible in
the afternoon. Continued warm advection on Monday will push
highs 10 to 15 degrees above normal.

At this point, low confidence forecast on Tuesday as far a the
timing of the rain. The timing will depend on how quickly
shortwaves rotating around the central Us trough can move
eastward and work to eject the east coast ridge. Additionally,
with the strong surface high holding on over northern New
England, how fast will the deeper moisture to the west of the
forecast area be able to spread eastward. Ensemble/blended
guidance is coming into somewhat of a better agreement on
timing, with the most likely time over the western half during
the morning, then the eastern half in the afternoon. It should
also be noted that as the showers encounter the drier and more
stable air over the region, the rain intensity will decrease as
it moves eastward. The probability of >0.10 inches of rain on
Tuesday range from 30%-70% with the higher numbers over Ohio.
Probabilities of >0.25 only reach 40%-50% over Ohio. So
currently, QPF with the Tuesday system should be light.

A strong gradient may lend to daytime gusts as high as 25mph to
40mph, with probabilities of exceeding 40mph roughly 45% to 60%
for the Pennsylvania ridges.

Tuesdays highs will remain well above normal.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
KEY MESSAGES:

- Risk for showers continues into Wednesday.
- Dry conditions are favored Thursday and Friday.

----------------------------------------------------------------

Light rain chances will continue on Wednesday, with above normal
temperatures.

Dry conditions are more likely than not behind the disturbance
with the reestablishment of high pressure, though weak upper
troughing will warrant watching for any shortwave development.

Western troughing is favored to start off April, making our area
slightly favored to see warmer and wetter than average
conditions through the first week in the month.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
VFR is expected through the TAF period as high pressure moves
east of the region. E-NE wind will gradually veer to the SE by
Monday morning. Some downsloping could result in gusts up to
20kt at DUJ and LBE, though a low level inversion should keep
the strongest wind aloft. Mid and high level clouds should
increase late tonight and Monday in warm advection aloft.

.Outlook...
High pressure should maintain VFR conditions through Monday
night until rain and restrictions return Tuesday and Wednesday
with the approach and passage of a cold front. VFR then returns
Thursday and Friday under high pressure.

&&

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

&&

$$

SYNOPSIS...Hefferan/22
NEAR TERM...Hefferan/22
SHORT TERM...22
LONG TERM...22/Milcarek
AVIATION...WM


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