236
FXUS61 KPBZ 181237
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
837 AM EDT Wed Sep 18 2024

.SYNOPSIS...
Limited, light rain chances persist today, primarily southeast
of Pittsburgh. A warmer and drier patter returns late week
through the weekend.

&&

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

- Light rain chances, mainly southeast of Pittsburgh today.
-------------------------------------------------------------------

An elongated, east-to-west trough axis remains situated across
the mid-Atlantic. This has maintained the pattern of easterly
flow, and will continue to do to for the near-term. Some
precipitation has formed on a spoke of vorticity on the edge of
the mid- level low, aided by moisture from the Atlantic. This
weak forcing is expected to push into portions of Pennsylvania
and West Virginia lowlands into the day today, although the main
forcing will be confided east of the Allegheny`s, with some
upslope flow possible for the higher elevations of eastern
Tucker County, where we expect the highest precipitation totals.

Accumulations through 07Z remain in the hundredths of an inch,
as dry air and downslope flow will continue to hinder
precipitation rates. These effects will continue into today as
the axis pivots west slightly.

Only around half of the ensemble members in the HREF have any
accumulation across portions of Pennsylvania south of I-80 and
West Virginia. Precipitation chances elsewhere remains quite
low with no forcing. Most-likely total precipitation for the
ridges remains a lack-luster couple tenths of an inch, with high
confidence storm totals are less than 0.5". This will do little
to nothing to alleviate drought concerns.

Precipitation chances taper overnight with weakening upper flow,
the eventually dry, northerly flow. The amount of lingering
cloud cover will largely influence fog potential.

&&

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

- Dry weather returns by Thursday
-------------------------------------------------------------------

A quiet, moderating day is expected Thursday as the
aforementioned surface low pulls out into the Atlantic, and the
area maintains dry north to northeast flow. Clearing clouds
will allow temperatures to top out slightly above normal, and
elevated dew points at nighttime will keep lows a tad warm as
well. Nighttime fog is possible once again. This is the most
likely scenario for Thursday.

There is a lower probability scenario, whereby the Atlantic
trough axis elongates and accelerates easterly flow, pulling
more moisture and perhaps some rain chances in while keeping
temperatures cooler. Even then, chances of notable rain are
quite low. This is not reflected in the current forecast given
it`s low (less than 20% probability), but will warrant watching.

&&

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

- Dry weather through the weekend, very low rain chances early
  next week
- Above average temperatures through early next week
-------------------------------------------------------------------

Little change to the long term forecast. Model ensembles are in
good agreement that the developing ridge to our west will
slowly build eastward, extending from the Texas Gulf coast into
eastern Canada by Saturday. This will also push the East Coast
trough further offshore with time. As a result, dry weather and
above- normal temperatures are forecast for Friday through
Sunday with high confidence.

Uncertainty ticks up a bit with the new work week.  A new trough
approaching from the Northern Plains/Upper Midwest has at least some
potential to weaken the ridge during the Monday/Tuesday period,
which would lead to cooler temperatures and an uptick in rain
chances.  However, cluster analysis shows that the majority of
ensemble members largely maintain the ridge over our region, which
would tend to keep the dry and warmer-than-normal pattern going. For
now, the forecast for early next week will lean towards this latter
scenario, pending future model runs.

Both the 6-10 day, 8-14 day, and 3-4 week outlooks all favor
above average temperatures, but precipitation will remain more
of a toss up with a potential pattern break down by the end of
the month.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
With an upper-level low drifting towards the Mid Atlantic
region today, moisture and weak ascent will created isolated
drizzle/light rain for areas east of PIT. Expect a lowering cig,
as moisture increases in the lower and mid levels. Most
airports will see a cig at or below 5kft east of a BVI-HLG line.
LBE and MGW should see MVFR cigs developing by mid morning,
with better low level moisture and limited rain chances.

Any MVFR should return to VFR by late afternoon/early evening,
as lower level moisture begins to decrease. A persistent east
wind is expected at around 5 kt.

.Outlook...
Occasional restrictions and showers are possible, especially
near MGW/LBE, through early Thursday, as the low slowly tracks
across the Lower Ohio Valley and Appalachians region.

VFR is then expected through Sunday as high pressure builds in.

&&

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

&&

$$

SYNOPSIS...Milcarek
NEAR TERM...Milcarek
SHORT TERM...Milcarek
LONG TERM...CL/Milcarek
AVIATION...WM/Hefferan