641
FXUS61 KPBZ 061221
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
821 AM EDT Thu Jun 6 2024

.SYNOPSIS...
Showers and isolated thunderstorms will end this morning as a
cold front exits the region. A secondary trough will result in a
few more scattered showers and possible thunderstorms this
afternoon and evening. An unsettled weather pattern is then
expected through the weekend under a persistent upper trough.

&&

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

- Showers end isolated thunderstorms end this morning
- Additional scattered showers and possible storms this
  afternoon
--------------------------------------------------------------

545 AM Update...
Made some adjustment to POPs based on current radar trends. Also
removed thunder from the forecast this morning, as lightning has
ended with continued waning instability.

Previous discussion...
Showers and isolated embedded thunderstorms will exit the
region this morning as a shortwave trough, and its associated
surface cold front, complete their passage. Partial clearing and
dry weather is then expected into early afternoon as surface
ridging briefly builds in.

A secondary surface trough, and broad troughing aloft, are
expected to cross the Upper Ohio Valley region this afternoon
and early evening. Cold advection in the mid levels will steepen
lapse rates, creating some instability. Capping above 10-15kft
should limit this instability, though scattered showers and
isolated thunderstorms are still expected as the surface trough
crosses.

High temperatures are expected to be around 5 degrees above
average, with only minimal cold advection behind the exiting
front.

&&

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

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

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

Isolated evening showers and thunderstorms should end tonight
as the reinforcing trough completes its passage. 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 and
thunderstorms. Another is expected for Saturday, though the best
upper support for any showers is expected to be mainly north of
Interstate 80.

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 WEDNESDAY/...
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 /12Z THURSDAY THROUGH MONDAY/...
A trough and an associated cold front exit the region this
morning, with showers tapering off from W-E. Ceilings start the
TAF period at a mix of IFR and MVFR, with gradual improvement
to VFR expected through the mid morning hours in the wake of the
frontal passage. The exception may be FKL and DUJ, which will
likely not see improvement until the afternoon. Steep low-level
lapse rates should promote wind gusts in the 20 to 25 knot
range by midday areawide, with some modest instability creating
isolated showers as well, particularly near and north/northeast
of PIT.

.Outlook...
Periodic restrictions and scattered showers are 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...WM
NEAR TERM...WM
SHORT TERM...WM
LONG TERM...WM
AVIATION...Cermak/22