966
FXUS61 KPBZ 110702
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
302 AM EDT Tue Jun 11 2024

.SYNOPSIS...
Cool and dry conditions continue today, followed by warming
temperatures but still dry weather Wednesday and Thursday.
Thunderstorm chances return Friday. Much warmer weather is
possible this upcoming weekend into early next week.

&&

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

- Cool and dry weather expected under building high pressure.

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

The upper shortwave that brought clouds and isolated showers to
the area on Monday is centered roughly over the northeastern
CONUS, with cloud cover along its southwest periphery still
impacting the high terrain and adjacent lowlands early this
morning. Farther west where clouds have cleared, effective
radiational cooling is allowing for patchy fog to form, with the
greatest concentration occurring in and around river valleys.

Morning fog will dissipate after sunrise and the clouds over the
eastern half of the area should begin to scatter out as the
upper trough continues to advance eastward off the New England
coast this afternoon. In its wake, high pressure begins to
build into the region, bringing drier deep-layer moisture
profiles and clearing skies. Meanwhile, northwest flow will
continue to support cold air advection (albeit weakening as the
trough gets farther to the east). This will keep temperatures
below seasonal as afternoon highs top out in the upper 60s
along/north of I-80 to low/mid 70s farther south.

&&

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

- Upper ridging Wednesday maintains dry weather and returns
  temperatures to near or above average across the region.

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Dry, quiet weather is expected tonight through Wednesday night
under weak ridging building over the area. Temperatures will
remain below climatological normals tonight as lows dip once
again into the upper 40s north to low 50s south. A warming trend
begins during the day Wednesday, but temperatures will be only
slightly above normal as a passing trough well to the north
along the the northern Great Lakes helps to lessen the impact of
the building ridge. As such, expect highs in upper 70s to low
80s, followed by lows Wednesday night in the mid to upper 50s.

&&

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

- Warm, dry conditions are expected Thursday.
- Long range models are hinting that thunderstorm chances return
  Friday, there is a chance that a few storms could be strong to
  severe.
- Models have been consistent that hotter conditions are
  favorable late week into early next week.

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

With a ridging building to our south and elongated trough over
central Canada, zonal flow will advance warm conditions over the
Midwest into the region. Confidence is high that upper-80s
to near 90s will be observed across the region on Thursday.
Minus the heat index values in the low-90s for portions of Ohio,
no hazardous weather is expected as conditions remain dry.

Trough advancement out of the north will bring a cold front
through the area late Thursday night into Friday. There is some
signal among global models that showers and thunderstorms
develop ahead of the front Thursday night, though there is
uncertainty regarding how far they make it into our area as
they move into an area of weaker instability and forcing. Still,
introduced low (generally 20-30%) rain chances over northwest
PA and northeast OH to account for this potential.

The better chance for showers and storms will occur along the
cold front itself as it pushes through the area during the day
Friday. Probability of organized convection (500 J/kg and 30kts
of effective shear) is 20% to 40% Friday evening with this
noted disturbance, meaning there is some low-end potential for a
few storms to become strong or severe.

Long range guidance has been consistent that a ridge axis will
build across much of the central and eastern CONUS thereafter
through the weekend and into the following week, bringing warm
and humid conditions to the area. There is a growing concern
that significant heat will be possible, especially as we get
into early next week, with NBM probabilities for high temps
reaching 95+ degrees on Monday continuing to run around 50% or
greater. The highest probabilities for impactful heat are noted
across eastern OH and the valleys and low elevations of western
PA, including urban centers like Pittsburgh where the heat
island effect typically leads to locally warmer temperatures
compared to surrounding areas. If this trend in guidance
continues, heat impacts will need to be closely monitored and
headlines may need to be considered.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
MVFR cloud deck is continuing to scatter into western
Pennsylvania overnight and bringing an end to CIG restrictions.
Clouds will linger longest north and east (FKL/DUJ/LBE) of PIT.
Given the building cool air mass, diminishing wind, and
relatively warm rivers, some patches of mainly valley-based fog
are possible and already appearing on satellite in areas that
have seen cloud cover dissipate. Latest hi res ensemble
probabilities favor a 50-60% chance of restrictions to MVFR VIS
for FKL and ZZV in the pre-dawn hours. Elsewhere where cloud
cover lingers, fog development shouldn`t be impactful.

Any fog should lift by 13z Tuesday morning, though probability
of MVFR CIGs at FKL/DUJ don`t indicate improvement until after
15-16z when flow backs to the west and cuts off the lake
moisture source. Scattered cumulus is expected during the late
morning/midday hours elsewhere. Northwest wind will generally
remain light at under 10 knots.

.Outlook...
VFR conditions are expected under building high pressure Tuesday
through Thursday. Restrictions in showers and thunderstorms return
Thursday night and Friday with another passing disturbance.

&&

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

&&

$$

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