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000
FXUS61 KPBZ 211602
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
1202 PM EDT Sun Apr 21 2024

.SYNOPSIS...
Frost/Freeze concerns are expected early Monday morning,
headlines will likely be need to be issued over the next few
hours. The next chance of precipitation will be Tuesday night
into Wednesday with a passing cold front.

&&

.NEAR TERM /UNTIL 9 PM THIS EVENING/...
KEY MESSAGES:

- Below average temperature and clouds are expected through a
  large portion of the day.

- No Hazardous weather.

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

Temperatures will continue to trend below average through the
afternoon/evening time period under cold, northwest flow.
Currently, there is an elongated upper-level trough situated
over eastern Canada.

Based on Hi-Res model guidance and the PIT 12Z model sounding,
850mb temps will likely range from -6C to -4C throughout the day
and prompt very little mixing of warm air. Radiational heating
will be a limiting factor as well with lingering clouds through
at least 5pm. Therefore, will continue to keep MaxT temps 15
degrees below the climatological norm (near 50F) for a majority
of the region. The probability of 50F or higher will remain
focused south of I-70.


&&

.SHORT TERM /9 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
Monday morning. NBM probs have been consistent between 60% and
80% northeast of PGH for freezing temperatures,  75% to 100%
areawide for temps at or below 36F. With light winds and limited
overnight cloud coverage, many locations could see a heavy
frost and/or freezing conditions.

Temperatures will recover to near 60F 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 /16Z 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...None.
OH...None.
WV...None.

&&

$$

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