800
FXUS61 KPBZ 070828
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
428 AM EDT Fri Jun 7 2024

.SYNOPSIS...
Probability of light precipitation will increase late this
morning north of Pittsburgh with passing shortwave. Below
average temperatures are also expected into late Saturday.

&&

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

- Pockets of river valley fog will continue to develop early
  this morning east of Pittsburgh.
- Probability of rain shower activity increases after day break
  north of Pittsburgh with a passing shortwave.
- Areas north of I-80 may observe a few thunderstorms; small
  hail may develop.
- Confidence is high that rainfall total amounts through Friday
  evening will be less than 0.25 inches.

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


A passing surface trough is created enough lift early this
morning to create a few stray showers across the region.
Probability of precipitation decreases below 10 percent just
before 3am.

With noted remnant moisture, light winds, and some breaks in the
clouds, river valley fog is noted northeast of Pittsburgh on
Nighttime Microphysics GOES-16 satellite. However, confidence is
high that fog will not be an issue during the early morning
commute with passing clouds from the northeast with a new
shortwave.

Rain showers probabilities increase after 10am north of
Pittsburgh with a passing shortwave and will likely continue
into the late evening. Hi-Res model soundings suggest pockets
of 50J/kg to 150J/kg low-level instability during peak heating.
Therefore, a few updrafts may lead to thunderstorm activity.
With a low freezing level (7kft to 8kft) and storm tops
projected near 10kft to 11kft, a few cell may produce small
hail. With rainfall activity being sporadic, low PWATs, and the
loss of a well- defined warm cloud layer, rainfall totals will
be range between a trace to 0.25 inches across the region;
higher amounts mainly focused near I-80.

High temperatures will range from mid-70s to mid-60s Friday
afternoon. The probability of higher temperatures will likely be
south of I-70, where clouds and precipitation will be heavily
absent for a large portion of the day.

&&

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

- Precipitation chances will diminish late evening.
- Dry, quiet, and cool weather is anticipated Friday night into
  Saturday morning with building high pressure from the west but
  prevailing northwest flow aloft.
- Near-normal temperatures return Saturday afternoon.

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

An elongated trough over the Ohio River Valley will continue to
advance cooler temperatures into the region Friday evening into
Friday night. With clouds gradually clearing under the loss of
diurnal heating and precipitation chances diminishing,
temperatures will likely trend below average with radiational
cooling and 850mb temps falling from 9C to 6C just before dawn.

Ridging to the west suggest a dry and quiet Saturday and the
return of near-normal temperatures

A shift from west to southwest flow will likely return warm,
moist conditions to the region Saturday night. However,
temperature will likely still range near the climatological
norm.

&&

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

- A passing cold front will return rain chances to the region
  early Sunday.
- Cool temperatures to start should warm next week.
- Hot conditions may develop late week with a noted ridge in
  long range models.

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

Convection returns early Sunday morning as a low pressure ejects
out of the Plains and quickly passes into the Ohio River
Valley. A few stray showers may evolve ahead a cold front, but
Hi-Res model suggest shower activity confided to the boundary.

In the wake of the cold front, expected clouds clearing and
temperatures recovering to near just slightly below average.

A strong ridge out of the Dakotas will continue to stream cool,
northerly flow into the region Monday into Tuesday. If the sky
remains cloud free, temperatures have the chance (NBM suggesting 40%
to 60%) to fall below 50 degrees north of Pittsburgh and along
the ridges.

Precipitation chances remain low (less than 30%) Monday through
Wednesday given long range uncertainty of a developing
disturbance.

Long range models are suggesting a pattern shift (June 13th-
June 15th) as a ridge axis builds and returns warm conditions to
the region. The NBM50th percentile is suggesting hot conditions
Thursday into Friday as temperatures range in the upper-80s to
low-90s.

&&

.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
VFR conditions are expected through the TAF period. Areas of mid
level clouds will cross the region tonight, around an upper low
centered across Ontario and the Great Lakes region. Model
soundings and the CU rule indicate a broken diurnal cumulus
layer will develop Friday morning as convective temperatures are
reached, and continue through the day. Scattered showers are
expected, mainly north of PIT, with that area in closer
proximity to the low, and more favorable moisture. An isolated
thunderstorm is also possible, though chances remain too low for
inclusion in the TAF at this time.

A sufficiently tight pressure gradient, and mixing, will result
in west wind gusting to 25kt during the daylight hours on
Friday. Clouds should gradually decrease Friday evening as
temperatures fall below convective thresholds. Wind will also
diminish with decreased mixing.

.Outlook...
Periodic restrictions and scattered showers are then expected
through Monday as a slow moving upper low persists across the
Great Lakes region. VFR should return Tuesday under high
pressure.

&&

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

&&

$$

SYNOPSIS...Hefferan
NEAR TERM...Hefferan
SHORT TERM...Hefferan
LONG TERM...Hefferan
AVIATION...WM