-- Discussion containing changed information from previous version are highlighted. --
459
FXUS61 KPBZ 161728
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
128 PM EDT Thu May 16 2024

.SYNOPSIS...
Dry conditions and seasonable temperatures expected today as
high pressure transitions across the region. Periodic showers
and a few afternoon storms are then expected through the
weekend.

&&

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

- Dry conditions, relatively light wind, and temperatures around
  5 degrees above normal.
  _____________________________________________________________

Update at 10:30 AM focused on generally minor updates to sky and
hourly temp/dewpoint grids. Low stratus will continue to burn
off over the next couple of hours, leaving a scattered/broken
cumulus deck. Low-chance terrain-induced afternoon showers are
still on the table.

Previous discussion...

Patchy morning fog and lower stratus is expected to improve this
morning with the onset of diurnal heating and influence of
surface high pressure. The rest of the day will be characterized
by generally dry weather, a mix of scattered to broken cumulus,
and temperature rising to around 5 degrees above normal as
an upper level ridge passes.

The other item of note is a slight increase potential for low
probability showers and thunderstorms this afternoon along the
higher terrain. Hi-res models suggest there may be enough
destabilization with heating plus weak terrain convergence to
promote the necessary lift under the ridge axis for such
development. Again, most locations are likely to remain dry but
areas along the Laurel Highlands and WV high terrain can`t rule
out a brief afternoon, non-severe storm.

&&

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

- Near to above normal temperature will continue.
- Shower chances return Friday.
  ______________________________________________________________

A weak trough is progged to push across Michigan and SW Ontario
on Friday, giving a glancing blow to the forecast area.
Instability is marginal but may be enough for a few
thunderstorms, primarily west of PGH as the airmass will be
moist, with MUCAPE of 1,000 to 1,500 j/kg.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
KEY MESSAGES:

- An upper trough will maintain unsettled weather through the
  weekend.

- Ridging should result in dry weather Monday and Tuesday with
  shower chances increasing by Wednesday
- Temperatures near or above normal are expected
  ______________________________________________________________

Another weak upper trough, much like observed earlier in the
week will move slowly up the Ohio Valley on Saturday with
continued chances of showers and thunderstorms. Trends have been
for this system to head farther south toward VA/NC on Sunday,
which would result in less chance of showers for forecast area
Sunday. Will leave shower chances in Sunday, but if trends
continue it may end up drier Sunday than forecast.


Upper low then appears to get trapped along the NC coast, with
SW-NE ridging extending into Upper Ohio River Valley with warm
and dry conditions likely Monday and Tuesday.

Multi-model guidance then brings a fairly significant trough
through the Great Lakes and Ohio Valley by midweek, which would
likely result in showers and thunderstorms.

&&

.AVIATION /17Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
VFR expected through at least 10z as upper level ridging crosses
overhead and surface high pressure reorients to the east.
Diurnal cu will continue to become more scattered through the
afternoon.

The next low pressure system will approach Friday morning, with
shortwave activity initially lifting north of the region.
Showers with low probability thunderstorms are likely ahead of
this feature, favoring eastern OH to northwest PA where
forcing/lift will be greatest. Variations in timing remain
possible while current forecasts omit thunder given low
probability of generation, let alone terminal impact.

.Outlook...
Isolated to scattered thunderstorms will remain possible in the
wake of the morning wave passage. Upper trough passage to the
south Saturday will maintain shra/tstm chances focused south of
KPIT, with varying degrees of restriction potential.

VFR and dry weather become high probabilities Sunday into Monday
under the influence of high pressure.
-- End Changed Discussion --

&&

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

&&

$$

SYNOPSIS...88
NEAR TERM...CL/88
SHORT TERM...88
LONG TERM...Craven/88
AVIATION...Frazier