Area Forecast Discussion
Issued by NWS Pittsburgh, PA

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS61 KPBZ 292350

Area Forecast Discussion
National Weather Service Pittsburgh PA
650 PM EST Wed Nov 29 2023

Warmer temperatures are expected Thursday and Friday, with much
warmer temperatures this weekend. Widespread rain chances return
early Friday with periodic rain chances continuing into early
next week.


Mostly clear skies will dominate tonight with the departure of a
weak shortwave trough and arrival of a brief high pressure
ridge. The 00Z sounding has shown pronounced dry air intrusions
above 700mb that are expected to lower and keep clouds to a
minimum through the period. Though the region does sit in a
notable pressure gradient, winds are expected to remain light
through the overnight period with decoupling from the surface.
Aloft, warm advection will continue in southwest flow. Clear
skies and light winds will lend to lows dropping into the middle
20s in radiative cooling with a shallow, steep surface
inversion forecast.

Warm advection is expected to continue into Thursday. As the
shallow, nocturnal inversion erodes in mostly clear skies, a
rapid rise in temperature is expected beyond daybreak.
Insolation and mixing into the warm cap will result in high
temperatures creeping slightly above average. High clouds are
expected to increase in coverage throughout the day with upper
moisture advection ahead of the next weather system.


A deepening trough and developing surface low over the Southern
Plains will shift northeastwards into the Mississippi Valley
overnight Thursday into Friday. Light rain may be possible
overnight, primarily across OH and NW PA, with an area of
convergence between this feature and a more broad northern
stream trough, though probability remains low.

More widespread rainfall is expected near daybreak Friday
morning as the surface low shifts into the Ohio Valley. However,
models continue to weaken the associated upper trough, becoming
more of an open wave by Friday. With waning upper support
rainfall amounts are expected to remain generally light, on the
order of a half inch or less through Friday night. Speaking of
which... light rain and drizzle will likely linger into early
Saturday morning as the weakening surface low slows forward
progress over the southern Great Lakes Friday into Saturday and
a secondary shortwave crosses. Drier weather is expected by
Saturday afternoon/evening with increasing subsidence.

Temperature will remain near to above average through the short
term, with Saturday being the warmest day as temperatures push
into the mid/upper 50s.


The broad west coast trough/east coast ridge type pattern
previously described will break down with the next upper trough
passage. Timing and synoptic details of that trough remain
elusive as well as any additional shortwave movement before its
arrival. Confidence is high the trough axis should arrive by
Monday afternoon and generally to persist through midweek.
Though ensemble spread remains elevated through this period,
there is enough consensus to suggest the following basic trends:

- Above normal temperature will remain Sunday into early Monday.
- Temperature will trend near to below normal by Wednesday.
- Precipitation is likely to occur from Sunday through the
  middle of next week, but timing and extent of any dry periods
  remains fuzzy.


Latest satellite imagery is showing the low-end VFR cloud deck
gradually departing to the east, with all terminals clear by the
start of the 00Z TAF period except DUJ which should clear out
shortly, in the 01-02Z timeframe. Clear skies and light south-
southwest winds are then expected tonight. Some high clouds move
in during the day Thursday and south-southwest winds increase to
around 10 knots with infrequent gusts to 15-20 knots.

Ceilings gradually lower towards the tail end of the TAF period
and beyond as the next low pressure system approaches. Numerical
guidance also indicated the potential for a southwesterly low-
level jet setting up in the 01/00Z to 01/06Z timeframe, which
could produce LLWS at area terminals. Values at this time
appear to be just below the 30 knot threshold, but this will
warrant monitoring for possible inclusion in future TAF cycles.

Restrictions and rain return Friday through the weekend as a
series of low pressure systems move through the area.





NEAR TERM...Milcarek
SHORT TERM...Rackley
LONG TERM...Rackley/Frazier
AVIATION...Cermak/CL is the U.S. government's official web portal to all federal, state and local government web resources and services.