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000
FXUS61 KPBZ 190505
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
105 AM EDT Fri Apr 19 2024

.SYNOPSIS...
Precipitation chances return early this morning with a passing
front, a few thunderstorms may occur. The potential for
frost/freeze impacts increases Sunday and Monday morning.

&&

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

-  Overnight low temperatures will trend above average with
   linger low-lvl moisture and cloud coverage increasing with an
   approaching disturbance.

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

For the evening update...slowed down the onset of the showers
just a bit. A t/td spread of close to 30 degrees this evening
will make it difficult for anything but sprinkles to reach the
ground until surface dewpoints start to rise. 18z model data is
showing an increasing surface southeasterly flow, which will
continue to support the drier air near the surface.
Additionally, as the shortwave associated with the surface from
digs into western Ohio late tonight, minor heights rises are
expected over much of the region, increasing subsidence. Rest of
the forecast in good shape.

The progression of ridging over western Ohio into western PA
this evening will support mainly clear skies this evening.

Clouds will increase overnight amid warm, moist advection ahead
of the next shortwave system set to traverse the Ohio River
Valley Friday. Therefore, above average temperatures will
continue into the overnight hours.

&&

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

- Showers and low probability thunderstorms are expected ahead
  of a cold front Friday. Lightning will be the main threat.
- Seasonable temperature and dry weather expected through the
  weekend.
- Potential for frost and/or freeze impacts each of Saturday and
  Sunday mornings.
----------------------------------------------------------------

An approaching shortwave and cold front will increase the
chances of showers before dawn Friday. There could be a few
isolated thunderstorms south of Pittsburgh will elevated
instability from lingering dry air from the eroding ridge.
Lightning will likely be the only threat early Friday morning.

The probability of precipitation decreases from west to east
with the passage of the cold front late Friday and decreasing
low-lvl moisture.

Confidence is high that an elongated trough over the Great
Lakes will increase cooler conditions over the weekend. For
Saturday and Sunday, temperatures will trend 5 degrees below
average.

With cooling temperatures, the potential for early morning
frost/freeze conditions Saturday night into Sunday will be
elevated in some areas. For our county warning area, all
counties but Tucker County are experiencing active vegetation
growth. Therefore, frost/freeze products may need to be issued
in the 24 to 48 hours.

&&

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


- A building ridge over the Midwest late Monday will increase
  the chances of near or above temperatures early next week.
- Next precipitation chances are likely to be Tuesday into
  Wednesday with crossing low pressure. The confidence in
  thunderstorms is low.
- Ensembles favor dry conditions outside of that period.
-------------------------------------------------------------------

Dry, quiet weather is anticipated Monday as a ridge, that was
over the central CONUS, advances east. Near to above
temperatures are expected to return.

Precipitation chances return late Tuesday into Wednesday as a
shortwave passes through the Great Lakes region. Trough depth
and axis timing remains varied among ensemble members, but they
all favor a shower environment with low to limited lightning
potential.

Long range ensembles favor ridge building over the western Great
Lakes in response to a deepening trough over the western CONUS
for the late week period. The expectation is for area
temperature to once again rise with any passing shortwave posing
greater thunderstorm potential.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
A front will cross from W-E from today, bringing relatively
light showers, MVFR cigs, and a WSHFT from S to WNW. Cig
restrictions will be slow to develop after precipitation onset
with dry low level conditions. Improvement back to VFR is
expected by evening with dry advection and a building surface
ridge, though mid level cigs will continue under a broad upper
trough.

.Outlook...
A ridge of high pressure at the surface will maintain VFR
conditions into next week. Showers and potential restrictions
return late Tuesday with an approaching cold front.

&&

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

&&

$$

SYNOPSIS...Hefferan
NEAR TERM...Hefferan/22
SHORT TERM...Hefferan/Frazier
LONG TERM...Hefferan/Frazier
AVIATION...88