Area Forecast Discussion
Issued by NWS Pittsburgh, PA

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FXUS61 KPBZ 252346
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
746 PM EDT Mon Mar 25 2024

.SYNOPSIS...
Fire weather danger is expected today due to gusty conditions
and low relative humidity, a Special Weather Statement was
issued in collaboration with our partners. Downslope wind gusts
this evening into tomorrow have prompted a Wind Advisory for
areas east and southeast of Pittsburgh. Rain chances increase
after 6am Tuesday, ahead of a cold front.

&&

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

- A Special Weather Statement (SPS) continues through 8pm for
  Ohio and West Virginia due to fire danger today. Low relative
  humidity and gusty conditions will result in an increased
  risk of fire start and spread.
- A Wind Advisory has been issued for downslope potential late
  this evening and into Tuesday.

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

An elongated ridge over the East Coast has returned warmer
conditions across the region compared to yesterday. However,
with lingering dry air relative humidity has dropped this
afternoon and will continue to range between 30% to 20%
through 8pm due to deep mixing. Wind gusts between 20mph to
25mph have also been measured across the region due to advancing
disturbance to our west enhancing the gradient wind. The
combination of wind and MinRH values poses a fire danger risk
into the evening. A Special Weather Statement was issued in
collaboration with surrounding WFOs and the State Foresters in
West Virginia and Ohio this morning. Despite low relative
humidity in Pennsylvania, the 10 hour fuel moisture was measured
above the 10%, the noted threshold of concern. Therefore, no
Special Weather Statement was issued for western PA. It is
advised to exercise caution if handling open flames or equipment
that creates sparks in counties within the SPS.

A Wind Advisory was issued along the ridges of Pennsylvania and
West Virginia after 7pm this evening due to downslope winds.
Probabilities are high that localized wind gusts over 50mph from
the southeast could create impacts: unsecured objects may blow
away, tree limbs could be blown down, and power outages may
increase early Tuesday morning.

Otherwise, dry and above normal conditions are likely today with
a building ridge over the Ohio River Valley. Temperatures will
10 to be 15 degrees above the climatological normal.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY/...
KEY MESSAGES:

- Strong wind gusts (+50mph) along the ridges of West Virginia
  and Pennsylvania is expected tonight into Tuesday afternoon
  due to downsloping; Wind Advisory continues into early Tuesday
  afternoon.
- Rain chances return to the region after 5am Tuesday with an
  approaching disturbance.
- Scattered light showers continue Wednesday due to slow
  progression of the cold front.

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

An upper-level ridge will remain parked over central PA tonight.
This will slow the eastward movement of an upper level wave,
currently over the central CONUS. Therefore, dry conditions will
continue into tonight.

With prevailing winds from the south and increase cloud
coverage, overnight low temperatures will remain above average
by 10 degrees.

The passage of the low-lvl jet late tonight will increase the
risk for strong wind gusts over the ridges as long as the
the boundary layer wind direction remains perpendicular to the
ridge axis and enhances downsloping. Hi-Res model guidance
probabilities for Wind Advisory criteria are considered high
(above 80%) early Tuesday morning. Gusts could range between
50mph to 55mph between 2am to 6am, especially for the PA ridges.
Therefore, the Wind Advisory continues for the Laurel Highlands
and West Virginia ridges.

Lingering dry conditions will likely hold off most rain shower
activity through dawn. The peak period for rainfall in eastern
Ohio will likely be between 7am to 1pm; 1pm to 6pm for areas
east of Pittsburgh with the progression of the pre-frontal
trough. Numerous CAMs depict a narrow region that could see
training showers with upper- lvl winds running parallel to the
trough. A the moment, probabilities are elevated (above 70%) for
0.45 to 0.65 inches of rain stretching north of I-70 in eastern
OH and continues towards the shore of Lake Erie. This axis
could shift east of west by 20 to 30 miles and could reside over
the PA/OH border or miss our CWA entirely. Outside this small
mesoscale feature, expected 0.10 inches to 0.30 inches across
the region through 10pm Tuesday.

There will likely be a brief break in precipitation activity
between 10pm and 3am before remnant broken showers cross the
region along the cold front. Note, there could be thunderstorm
activity in western OH along the cold front. However, the
probability of lightning is expected to diminish east of
Columbus, OH with reduced elevated instability.

With the slow eastward movement of a cold front, due to the
stubborn east coast ridge, the risk for scattered showers will
continue on Wednesday. However, a large upper level dry slot
will spread across the region ahead of the front, greatly
limiting rainfall amounts. Its not out of the question that much
of the rain directly along the front will dissipate Wednesday
afternoon.

Temperatures remain above normal on Wednesday.

&&

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

- Sunshine is favorable over eastern OH on Thursday, clouds may
  linger over Pittsburgh and the ridges through the late
  afternoon/evening.
- Widespread dry conditions are expected Friday.
- Precipitation chances return Easter weekend with the potential
  of shortwaves tracking across the Great Lakes within an
  elongated trough over the Northeast.

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

Drier conditions are likely Thursday and Friday with building
high pressure. Although, an isolated shower can`t be completely
ruled out over the ridges on Thursday due to upsloping.

Long range models are in agreement that a closed upper-lvl low
will advance into southern California over the weekend and
amplify a ridge axis over the Great Plains. Troughing will
likely develop over the Northeast and could keep temperatures
near normal or slightly below normal for Easter. Weak shortwaves
ejecting out of central Canada, tracking through the Great
Lakes, and entering the Ohio River Valley may elevate the
potential for precipitation over the weekend as well.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
VFR conditions will prevail through at least early Tuesday
afternoon. Scattered to broken upper level clouds will continue
to slide across the area ahead of approaching low pressure still
centered well off to our west. Breezy winds from this afternoon
should begin to settle some over the next few hours as nocturnal
decoupling occurs. Meanwhile, a 40-50 knot low-level jet is
expected to set up overhead after 00z, with all sites aside
from LBE (which will remain breezy due to downsloping
enhancement) seeing an increasing low-level wind shear threat
after 06Z and lasting through the remainder of the overnight
period. The boundary layer should begin to mix again Tuesday
morning, resulting in a return of surface gusts to 15-20 knots
and thus ending the wind shear threat after roughly 14Z.

Rain will arrive from the west beginning late Tuesday morning,
but will be battling a lot of surface dry air at onset so cigs
and vsbys are expected to see little impact at first. Hi-res
ensemble probabilities indicate most likely precipitation onset
around 11z for ZZV, 16z for FKL to PIT to MGW, and after 18z for
LBE/DUJ, which may even be a bit aggressive given the extent of
the dry air in place. Probabilities generally hover around
30-50% for MVFR ceiling restrictions west of PIT after 18Z, with
probabilities farther east remaining much lower (<20%).
Meanwhile, probabilities for MVFR visibility restrictions in
rain are around 40-60%, however unlike the cig restrictions
mentioned above, these apply to all area terminals since the
entire area has a medium to high (60-90%) chance of seeing rain
at some point between 12Z and the end of the TAF period.

.Outlook...
Restrictions may linger into early Wednesday with lingering
boundary layer moisture before the passage of a cold front in
the morning, but VFR then returns with high confidence for
Thursday and Friday under high pressure.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...Wind Advisory until 1 PM EDT Tuesday for PAZ073>078.
OH...None.
WV...Wind Advisory until 1 PM EDT Tuesday for WVZ510>514.

&&

$$

SYNOPSIS...Hefferan
NEAR TERM...Hefferan
SHORT TERM...Hefferan
LONG TERM...Hefferan
AVIATION...Cermak/MLB


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