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000
FXUS61 KPBZ 211141
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
741 AM EDT Sun Apr 21 2024

.SYNOPSIS...
Below normal temperatures today will recover to near normal values
heading into the work week. The next chance of precipitation will
be Tuesday night into Wednesday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
KEY MESSAGES:

- Below average temperature and dry weather continues today.

- No Hazardous weather.

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

Surface ridging remains in control today, with a dry forecast
being maintained. Frost/freeze headlines will be allowed to
drop at 8 AM. Cloud cover likely negated impacts for a great
deal of the CWA this morning. These clouds will largely linger
into the afternoon, becoming more cellular with time as low-
level mixing/heating commences. Late- day moderation in 850mb
temperature will aid in breaking the clouds up further towards
evening, with sunset likely visible for the majority of the
region.

Winds will pick up again (but not as strong as observed
Saturday) by late morning as the boundary layer extends up to
800-750mb.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
KEY MESSAGES:

- Below average temperature and dry weather is expected to
  continue through Monday.

- Frost/Freeze headlines likely needed again overnight.
----------------------------------------------------------------

Below average temperatures and dry conditions will continue into
Monday with Frost/Freeze products likely needed again for
tonight / Monday morning. NBM probs show between 60% and 80%
north west of PGH for freezing temperatures and 75% to 100%
areawide for temps at or below 36F...and with light winds and
limited overnight cloud coverage many locations could see a
heavy frost and/or freezing conditions. Temperatures will
recover to near 60 during the day with building high pressure
and abundant sunshine, but will still be several degrees below
normal.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
KEY MESSAGES:

- The potential for Frost/Freeze headlines decreases through
  Wednesday under warm, moist advection.
- The next low pressure system and associated precipitation
  chances is likely for late Tuesday into Wednesday.
- Frost/Freeze potential returns Wednesday into Thursday with a
  passing trough over the Great Lakes.
-------------------------------------------------------------------

A flux in low-lvl moisture and southwest flow under a ridge will
decrease the potential of frost/freeze headlines through at
least Wednesday.

Near to above average temperatures are anticipated Tuesday
afternoon ahead of an approaching cold front and its associated
trough. Probability of measured precipitation increases from
west to east after 18Z Tuesday. The axis of heavier rainfall is
expected to be north of Pittsburgh, associated with stronger
forcing and perhaps lake enhancement on the backside of the
front. For rainfall amounts through Wednesday, the latest run of
the NBM suggest areas south of Pittsburgh could range from 0.15
inches to 0.40 inches; areas near I-80 could range from 0.25 to
0.60 inches. Along with rain, shallow instability (15J/kg to
50J/kg) may prompt some thunderstorms along the cold front.

With clearing clouds late Wednesday and cold advection, the
potential for frost/freeze conditions across the region
increases again early Thursday morning.

The late week period will be defined by the progression of the
upper trough through the northeast CONUS and the rapidity of
height rises in its wake. Dry weather will be favored given
high confidence of surface high pressure, with the degree of
temperature recovery in the post-cold front passage environment
dictated by said height rises.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
Mid-level moisture ahead of an approaching 500mb trough will
maintain high-based stratocumulus this morning in the 5k-6k foot
range. Diurnal heating will add additional cumulus to the
patchy mid-level deck before dry advection and subsidence during
the late afternoon erode area cloud cover. Surface ridging will
aid in keeping conditions mostly clear tonight.

Afternoon northwest wind gusts between 15 to 20kts are possible
possible given deep mixing, with wind becoming light and
variable overall after sunset.

.Outlook...
The approach and passage of a low pressure system late Tuesday
into Wednesday will be the next period with restriction
potential along with widespread rain. There is high confidence
in high pressure supporting VFR conditions to end the work week.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...Frost Advisory until 8 AM EDT this morning for PAZ020-021-029-
     031-073-075.
     Freeze Warning until 8 AM EDT this morning for PAZ007>009-
     013>016-022-074-076>078.
OH...Frost Advisory until 8 AM EDT this morning for OHZ039>041-
     048>050-057>059-068-069.
WV...Frost Advisory until 8 AM EDT this morning for WVZ001>004-012-
     021-509>513.

&&

$$

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