311
FXUS61 KPBZ 111115
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
715 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 /UNTIL 6 PM THIS EVENING/...
KEY MESSAGES:

- Cool and dry weather expected under building high pressure.

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

Morning Update...With the exception of some morning fog as the
main impact, the forecast will remain on track. Will keep the
fog in the forecast at least through 14Z. Have adjusted temps
and dew points slightly and trended them into the coming day.

Previous discussion...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 /6 PM THIS EVENING 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.

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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 /11Z TUESDAY THROUGH SATURDAY/...
Expect some lingering restrictions across the area through 14Z
this morning as much of the area will see lifting MVFR cigs.
Currently, ZZV and HLG have the most impacts due to dense fog
and low stratus, still this should improve by 14Z.

Scattered cumulus is expected during the day today and into the
afternoon. Northwest wind will generally remain light at under
10 knots. Fog is a potential again tonight but confidence is a
bit lacking due to a drying airmass.

.Outlook...
VFR conditions are expected under building high pressure
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/Shallenberger
SHORT TERM...Cermak
LONG TERM...Cermak
AVIATION...Shallenberger