385
FXUS61 KPBZ 062356
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
756 PM EDT Thu Jun 6 2024

.SYNOPSIS...
An unsettled weather pattern is expected the remainder of the
week and through the weekend under a persistent upper trough,
resulting in periodic chances of isolated to scattered showers.

&&

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

- Isolated to scattered showers this afternoon/early evening.
--------------------------------------------------------------

Update at 345 PM focused on upping PoPs a bit into the 30-55
percent range from much of the region as these scattered showers
cross, supported by troughing at the surface and aloft.
Continued to leave thunder out of the forecast as strong capping
below the -10C level will preclude the generation of lightning.
Also upped sky cover, as fast flow spreads out the cloud tops of
these rather short showers. Minor changes to temps as well.

Previous discussion...

A surface trough crossing the Upper Ohio Valley region will
result in isolated to scattered showers this afternoon and early
evening. Cold advection in the mid levels will steepen lapse
rates and create some instability, however, capping between
700mb and 500mb will mitigate any thunder/lightning as updrafts
will not be tall enough for ice.

Highs should top out several degrees above normal for the
first week of June.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
KEY MESSAGES:

- Persistent upper trough maintains an unsettled pattern
- Cooler temperatures expected

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

Isolated evening showers will end tonight as the trough
exits east. An upper low will drift across southeastern Canada
and the Great Lakes region Friday through Saturday night.
Individual shortwaves rotating around the low will keep an
unsettled pattern across the Upper Ohio Valley region through
the remainder of the period.

A diurnal trend to the cloud cover is expected, with low
convective temperatures in place and cool air aloft. One of
these shortwaves is expected to cross the Upper Ohio Valley
region on Friday, with isolated to scattered showers. Another
is expected for Saturday, though the best upper support for any
showers is expected to be mainly north of PGH.

A stronger shortwave rotating around the low is expected to
cross the region Saturday night, with scattered showers across
much of the area. Temperatures are generally expected to average
around 5 degrees below seasonable levels through the period.

&&

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

- Unsettled pattern through mid week under a series of upper
  troughs
- Cool temperatures to start should warm next week

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

Shortwave troughs rotating around the upper low, mentioned in
the short term section of the discussion, will maintain
scattered showers on Sunday and Monday, though much of the time
in any one location will be dry.

Mainly dry weather is expected on Tuesday as the upper low exits
the New England coast, and ridging briefly builds in. A
shortwave trough is expected to advance eastward from the Plains
region Tuesday night, crossing the Upper Ohio Valley region on
Wednesday. Scattered showers are expected with the approach and
passage of the trough.

Temperatures should start out a few degrees below average
Sunday and Monday, before returning to near, or above average
readings by mid week.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
Some widely scattered showers forming off of remnant outflow
boundaries, which have caused brief shifts in wind direction,
will wane after sunset and VFR conditions prevail overnight with
light wind 5 knots or less.

Wind will increase with mixing on Friday morning out of the west
with gusts to 15-20 knots. Diurnal cumulus will develop beneath
a building subsidence inversion as high pressure noses in from
the southwest. An upper wave will pass by the northern part of
our area bringing a chance (30-40%) of scattered showers for the
afternoon. There is also a low confidence chance (~30%) of a
brief period of MVFR CIGs early Friday morning for FKL but
conditions will otherwise remain VFR through the TAF period.

.Outlook...
Periodic restrictions and scattered showers are then expected
through Sunday as a slow moving upper low persists across the
Great Lakes region.

&&

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

&&

$$

SYNOPSIS...CL/88
NEAR TERM...88
SHORT TERM...WM/88
LONG TERM...WM/88
AVIATION...Cermak/MLB