Area Forecast Discussion
Issued by NWS Pittsburgh, PA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KPBZ 231940
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
340 PM EDT Sat Mar 23 2024

.SYNOPSIS...
Dry weather and a warming trend is expected through early next
week. Low fire weather concerns prevail Monday. The next chance
of rain returns Tuesday. Temperature is favored to stay above
average to close out the month.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
KEY MESSAGES:

- Seasonally cool conditions will prevail with decreasing cloud
  cover.

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

345pm update...
Area trends suggest widespread dense fog has ended or will end
shortly, thus the Dense Fog Advisory will expire at 4pm.
However, there likely will remain localized patches of freezing
fog that linger into this evening that offer a non-zero
probability for light ice accretion. This low probability impact
will be handled by an SPS through 9pm EDT for eastern Tucker
County, at which point ensemble models suggest some relief of
the weather hazard.

Rest of Discussion...

Upper level clouds are departing, but northerly flow over Lake
Erie, low-level cold advection, and a passing mid-level
shortwave trough will all be favorable for stratocumulus
maintenance for much of the day. This will act to limit daytime
high recoveries through this afternoon, even with the March
sun. Daytime mixing below the inversion may allow for gusts of
up to 20mph to 30mph this afternoon in an elevated pressure
gradient behind the low.

By the time late afternoon and evening comes around, there is
some indication that mixing will overcome saturation below the
inversion and allow drier air to clear some low-cloud cover,
particularly in eastern Ohio. If this does realize, temperatures
could peak a few degrees higher before sunset.

Overnight tonight, there is some deviance in the cloud cover
forecast. If mixing and clearing is more robust today, there is
a higher probability those clear conditions will persist
overnight. If not, some low clouds may linger, most likely for
the ridges and northwest Pennsylvania. Utilizing efficient
radiate cooling, lows are expected to bottom out around 10
degrees below average, with the most temperature uncertainty
tied to cloud cover uncertainty.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY/...
KEY MESSAGES:

- Dry conditions with a warming trend are anticipated through
  Monday.
- Favorable fire weather conditions return.

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

Western troughing will evoke a eastern ridging response for the
short term period. Surface high pressure will pass over on
Sunday; as it does so, light winds will shift from northerly to
easterly. Mixing into a dry subsidence inversion will allow for
clear skies Sunday. Upper moisture advection may allow for a
return of high clouds through the day on Monday. Ridging and
radiative effects will push surface temperatures near normal on
Sunday, then around 10 to 15 degrees above average on Monday.

With surface mixing tapping into drier air, minimum afternoon
relative humidities will sit between the mid 20s and mid 30s
both days. Sunday, this is of lower concern for fire weather,
because winds will remain light under the surface high and
recent rain has dampened fuels. On the other hand, Sunday will
allow 10 hour fuels the opportunity to dry out.

Into Monday, the low humidity will be more of a concern for
fire weather because daytime wind gusts will increase out of the
southeast as a pressure gradient tightens between the departing
high and approaching low. Probabilities of daytime gusts
exceeding 20mph are 60% to 90% north of I-70, with some localized
higher gusts possible in the ridges. With lower moisture in
fast-response fuels, this will justify keeping an eye on.
Conditions are susceptible for ignition and spread; low fire
risk is forecast.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
KEY MESSAGES:

- Rain chances return Tuesday through Wednesday night with above
  average temperature.
- Dry conditions are favored Thursday and Friday.

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

As the western trough migrates east, synoptic-scale forcing will
deepen a low over the upper-midwest. The affiliated cold front,
enhanced ascent, and accelerated upper flow will allow
precipitation chances to return Tuesday. There is still some
uncertainty in exact arrival time with uncertainty in trough
progression speed. At the earliest, rain may arrive Tuesday
morning, and at the latest, Tuesday evening. There is high
confidence all precipitation will fall as rain with temperatures
around 10 degrees above average. Low end QPF sits around a
tenth of an inch, and the high end currently sits around an
inch. There are no flooding concerns at this time.

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.

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 /20Z SATURDAY THROUGH THURSDAY/...
A slow improvement to MVFR cigs is expected to continue this
afternoon, with a return to VFR especially for airports west of
I 79 as high pressure begins to build in, and dry advection
occurs. Stratocu is expected to persist tonight for airports
outside of Ohio, though cig levels are uncertain. Kept a low VFR
cig for airports on the western edge of the cloud cover, with
MVFR for FKL, DUJ and LBE where better low level moisture is
progged. These areas also have a higher probability of MVFR cigs
in recent NBM guidance.

The clouds should gradually clear late tonight through early
Sunday morning as the high builds further across the Lower Great
Lakes/Upper Ohio Valley region. A tight pressure gradient
between low pressure along the East Coast, and high pressure
across the Midwest, will maintain gusty wind through early
evening. A decreasing gradient and loss of mixing should result
in gusts ending tonight, with wind veering to the NE on Sunday.

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

&&

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

&&

$$

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


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.