421
FXUS61 KPBZ 121327
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
927 AM EDT Mon Aug 12 2024

.SYNOPSIS...
Mostly dry conditions and slightly below-normal temperatures
expected to continue through mid-week. Rain chances increase by
the end of the week.

&&

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

- Temperatures remain below seasonal averages
- Dry weather and comfortable conditions today
-------------------------------------------------------------------

No changes needed at 9:30 AM. Morning PBZ sounding shows a good
deal of warm air above 750mb that will, in concert with
subsidence, keep expected cumulus field from building tall
enough to generate showers. Forecast is generally on track.

Previous discussion...

A dry and cool northwest flow aloft will provide another
pleasant day with no rain, plenty of sunshine and comfortable
conditions. Surface high pressure will glide across the Great
Lakes which will also assist in keep the area dry. Could see CU
develop with daytime heating especially across the northern half
of the forecast area.

&&

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

- Temperatures remain a couple degrees below average.
- Dry weather continues through midweek.
-------------------------------------------------------------------

Little change in the overall pattern through mid-week. The area
will remain under northwest flow aloft and high pressure will
be the main player at the surface. Temperatures will warm a bit
each day, especially on Wednesday, as some weak warm air
advection is anticipated.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
KEY MESSAGES:

- Below-normal temperatures moderate towards climatology in the
  second half in the week.
- Forecast uncertainty increases toward the end of the week with a
  shift to a more active pattern.
-------------------------------------------------------------------

By mid-week, the upper trough will begin to retrograde off to
our northeast and we remain positioned in northwest flow. The
general trend will be for gradual height rises and thickness
increases as ensembles shift the central CONUS ridge axis
eastward. Temperatures will continue to moderate Thursday and it
will remain dry as we enter a transition period in the upper
level pattern.

Ensemble clusters deviate from the mean by Thursday as a trough
entering the Pacific Northwest butts up against the ridge. The
strength of the lingering ridge is considerably questionable
given evidence of a multimodal distribution, as some ensemble
members show a more-amplified ridge axis while others depict
heights considerably below the ensemble mean. The general
evolution is for a break down of the ridge and reintroducing a
northwest flow pattern which suggests increasing precipitation
potential.

&&

.AVIATION /14Z MONDAY THROUGH FRIDAY/...
Into the day today, mixing and fair weather cumulus will
arrive, with winds increasing out of the northwest. Chances of
wind gusts exceeding 20 kts are roughly 0% to 20% and highest
for FKL and DUJ. A weak wave passing in the afternoon brings
around a 10% chance of a nearby shower for PA ports, this
confidence was too low to denote in TAFs.

Clearing is largely expected overnight as winds lighten and
veer with high pressure advancing.

.Outlook...
General VFR is expected through early week as surface high
pressure builds under broad upper troughing.

&&

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

&&

$$

SYNOPSIS...22/MLB
NEAR TERM...22/CL
SHORT TERM...22
LONG TERM...Kramar/22/MLB
AVIATION...MLB/Milcarek