823
FXUS61 KPBZ 110716
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
316 AM EDT Sat May 11 2024

.SYNOPSIS...
Low pressure tracking from Michigan into western New York State
is expected to bring showers and thunderstorms to the forecast
area into tonight. Showers are expected to end Sunday morning
with dry weather expected on Monday. The weekend will be about
10 degrees below normal on temperatures, with readings rapidly
climbing to nearly 10 degrees above normal for Monday.

&&

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

- Areas of fog early this morning
- Showers and thunderstorms today
- Small hail and gusty wind possible this afternoon
-------------------------------------------------------------------

Areas of fog have developed across much of the area this
morning. The highest concentration of the fog, and the lowest
visibilities, have been in the river valleys. Issued a Special
Weather Statement to highlight this for travelers this morning.
Will also continue to monitor the coverage of the fog for any
possible advisories.

The fog should mix out as winds increase between 12 and 13Z.
Otherwise, a shortwave trough and surface cold front will track
eastward out of the Great Lakes and Upper Midwest region today.
Increasing moisture and ascent in warm advection ahead of the
front will result in a band of showers moving across the region
from mid to late morning into the afternoon.

The cold front will quickly follow, with scattered showers and
thunderstorms developing. HREF MU CAPE values reach 500 j/kg
during the peak heating of the day. This, along with low
freezing levels around 5-6kft, should result in a potential for
small hail in some of the storms. 25-40kt low to mid level wind
and 40kt 0-6km shear should also result in a potential for wind
gusts up to 40 mph.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
KEY MESSAGES:

- Thunderstorm potential ending early this evening
- Scattered showers continue, mainly north of Pittsburgh
-------------------------------------------------------------------

THe cold front will complete its passage this evening, with the
thunderstorm potential ending. A mid and upper low across
southern Ontario and the Lower Great Lakes will drop
southeastward overnight, maintaining isolated to scattered
showers across the region. Cold advection overnight should
result in overnight lows averaging around 5 degrees below
seasonable levels.

&&

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

- Temperatures remain about 10 degrees below normal Sunday.
- Rapid warmup Monday to nearly 10 degrees above normal.
- Showers and thunderstorms return Tuesday/Wednesday.
-------------------------------------------------------------------

Cold upper 500 mb low of 5450-5480 meters over PA in the morning
will pull east over the Atlantic with large height rises on the
order of 150 meters expected during the day Sunday. Lingering
morning showers in the northeast part of forecast area should
end with significant drying by afternoon. It will remain cool
with highs in the lower 60s.

Short wave ridging is expected Monday with sunshine pushing
temperatures much higher. With mean 850 mb temps rising 8C in 24
hours, this will result in at least a 15 degree warmup with
highs 75-80. Given the tendency for NBM to run about 2F too cool
on days with strong insolation and deeper mixing, nudged MaxT up
a couple of degrees.

Guidance in relatively good agreement in bringing upper trough
across STL area Tuesday and up the Ohio River valley Wednesday.
Showers and thunderstorms will result Tuesday with southwest
flow bringing PWs around 1.25" to area. Showers may linger
Wednesday beneath upper trough.

Upper ridging builds on Thursday and dry conditions are expected
to return. Uncertainty begins to increase Thursday and Friday
with rather large 500 mb height standard deviations in the NBM,
so confidence in the late week forecast is relatively low.

&&

.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
Most airports east of the OH/PA border will see at least patchy
MVFR fog through early Saturday morning. Areas that cleared
late, such as FKL, DUJ, LBE and MGW, have a better potential at
IFR/LIFR fog. This fog should dissipate by 13Z as surface winds
and mixing increase.

A band of showers is expected to cross the region later this
morning into the afternoon under warm advection ahead of an
approaching cold front. MVFR visibilities are expected with
these showers.

The band of showers should exit the region by late afternoon.
Numerous showers and scattered thunderstorms are then expected
to develop along the cold front. Sufficient wind flow aloft, and
a low freezing level, should result in gusty wind and small
hail in some of the storms.

The cold front will exit the region this evening, with most
sites returning to VFR. A crossing upper trough will maintain
showers across FKL and DUJ, where MVFR is expected to continue.

.Outlook...
Restrictions are possible Saturday night and early Sunday under
a trough of low pressure. VFR returns Sunday afternoon through
Monday under high pressure. Restriction potential returns Monday
night through Wednesday under crossing low pressure.

&&

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

&&

$$

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