237
FXUS61 KPBZ 140531
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
131 AM EDT Tue May 14 2024

.SYNOPSIS...
A series of low pressure systems bring daily chances for
showers and thunderstorms Tuesday through the end of the week.
Temperatures will stay above normal throughout the week.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
KEY MESSAGES:

-Dry conditions and ample sunshine today with above normal
 temperatures.
 ______________________________________________________________

The upper ridge that provided warm and sunny weather to the area
today pushes off to the east tonight as an upstream trough
advances eastward into the Midwest. With the approaching trough
comes decreasing heights and increasing moisture, which will
support scattered shower activity overspreading the area from
the southwest, particularly after midnight. Persistent southerly
flow and increasing clouds will keep temperatures roughly 5-10
degrees above normal tonight.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
KEY MESSAGES:

- Widespread shower/thunderstorm chances return Tuesday and
  Wednesday.
- Minimal severe threat.
  ______________________________________________________________

The upper trough over the Midwest tracks eastward across the Ohio
Valley Tuesday into Wednesday, eventually sliding east of the
area by Wednesday night. Increasing moisture and ascent will
result in a greater coverage of showers and thunderstorms across
the entire area through that time, with activity tapering off
Wednesday night as an upper ridge begins to build in from the
west in the wake of the trough. Rainfall amounts are expected
to remain generally light through this system, with widespread
amounts forecast to remain in the 0.25-0.75 inch range.
Ensemble probabilities of storm total QPF greater than 0.5" is
roughly 60-70% south of I-70 and 40-50% farther north. In fact,
probabilities for an inch of rain in this 48 hour window are
near or less than 30% everywhere. That said, while widespread
rainfall amounts will be generally light, locally higher
amounts will remain possible if any locations see multiple
rounds of thunderstorms during this period, since the heaviest
rates can be expected in any storms. The severe weather threat
remains low as both instability and bulk shear will be marginal
at best during this period.

&&

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

- Dry conditions briefly return Thursday morning.
- Ensemble spread is still relatively high, but another trough
  appears to bring showers and thunderstorms back to the
  forecast late Thursday through the end of the week.
- Above normal temperatures continue.
  ______________________________________________________________

A weak upper ridge quickly builds into the area in the wake of
the departing trough, bringing a brief period of dry weather
Wednesday night into Thursday morning. However, another upstream
trough will be hot on its heels, digging into the Great Lakes
region and quickly ushering the upper ridge off to the east.
This will bring increasing chances for showers and storms back
to the area Thursday afternoon through the end of the week.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
Cigs will lower to low VFR/isolated MVFR this morning as a
shortwave trough, embedded in SW flow ahead of a parent trough
across the Midwest, approaches and crosses the region producing
showers. The showers should become scattered again this
afternoon as the initial wave exits to the northeast.

Some destabilization is expected by late afternoon into early
evening, with HREF MU CAPE near 500 j/kg south of a line from
PHD-BVI-LBE. This could result in a few thunderstorms
developing, as another vorticity maximum begins to approach the
region. Maintained the prob30 mention for this potential.

Low VFR cigs and scattered showers are expected tonight as the
next wave rotates around the main trough. Patchy MVFR cigs are
possible, mainly SE-NE of PIT where more favaorable low level
moisture is progged.

.Outlook...
Restrictions are likely, along with showers and possible
thunderstorms, Wednesday as slow moving low pressure crosses
the region. A brief return to VFR is possible Thursday as
ridging briefly builds in. Restrictions and showers return
Friday and Saturday with another slow moving low pressure
system.

&&

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

&&

$$

SYNOPSIS...88
NEAR TERM...88
SHORT TERM...88
LONG TERM...88
AVIATION...WM