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000
FXUS61 KPBZ 200505
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
105 AM EDT Sat Apr 20 2024

.SYNOPSIS...
Seasonably cool temperatures and dry conditions are expected
through the weekend with potential for frost/freezing
conditions Sunday and Monday morning. Building high pressure
will return above average temperatures mid-week.

&&

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

-  Dry and relatively cool conditions are expected.
-  No Hazardous weather.

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

Dry, quiet weather is expected overnight in the wake of the cold
front. Temperatures will be near the climatological average
due to lingering clouds.

&&

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

- Slightly below average temperature and dry weather expected
  through the weekend.
- Potential for frost and/or freeze impacts Sunday morning.
----------------------------------------------------------------

The Upper Ohio River Valley will be positioned underneath upper
troughing Saturday, including passage of the trough axis during
the afternoon hours. While the passage will reinforce the cold
advection across the region, maintaining temperatures slightly
below average, there will be a lack of deep moisture or synoptic
lift to generate showers, save for closer to the lake shore and
into NY state. Deep mixing with surface heating will keep
conditions gusty on Saturday. NBM probabilities of wind gusts
exceeding 20mph are near 100% with a period of gusts exceeding
30mph along the timeframe of the trough passage.

Fairly fast, zonal flow will be present thereafter and through
the weekend with high pressure building over the region at the
surface keeping conditions dry and cool.

With ridging in place, there remains a concern for frost/freeze
as much of the forecast area is now in the growing season both
Sunday Morning and Monday Morning. The latest NBM has a 40-60%
chance both days, especially north of Pittsburgh. There is a
concern that elevated winds could be a limiting factor Saturday
night but the high pressure will be more settled over the region
Sunday night. For now, will continue to highlight this in the
HWO.

&&

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


- The next low pressure system and associated precipitation
  chances is likely for late Tuesday into Wednesday.
- Ridging is favored for the late week period, pointing to
  rising temperature heading into the weekend.
-------------------------------------------------------------------

Though ensemble models vary in trough analysis moving across the
southeast U.S. Monday, the outcome remains the same for the
Upper Ohio River Valley: rising heights aloft and the influence
of high pressure will support dry conditions and seasonable
temperature Monday.

There is fairly high consensus on the next upper level trough
and associated surface low to drop from the north central plains
through the Great Lakes late Tuesday into Wednesday. Ahead of
the system, weak warm advection will support above normal
temperature and increasing cloud cover before the system`s
arrival. Widespread showers and low probability thunderstorms
are then likely as the system crosses the region. Depth of the
upper trough remains the biggest uncertainty during this period,
which will strongly influence the timing of precipitation
passage and degree of cold advection behind the system.

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 /06Z SATURDAY THROUGH WEDNESDAY/...
Broad upper troughing and impinging surface high pressure will
support VFR conditions and erosion of sub-5kft stratocu layers
during the early morning hours today, leaving waves of mid to
high level clouds. Shortwave passage this afternoon will push
through a secondary cold front, promoting slight veering of wind
profiles to NW and reinforce sfc gradients that promote 20 to
30kts daytime gusts. No precipitation is expected with the
front.

.Outlook...
High confidence in VFR conditions through a majority of Tuesday
under the influence of high pressure. Passage of a low pressure
system will bring widespread precipitation and restriction late
Tuesday into Wednesday. Ensemble models favor dry weather and
VFR conditions to end the work week.

&&

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

&&

$$

SYNOPSIS...34
NEAR TERM...Hefferan/34/88
SHORT TERM...34
LONG TERM...34/Frazier
AVIATION...Frazier