Penn Hills, Pennsylvania 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

033
FXUS61 KPBZ 251005
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
505 AM EST Thu Dec 25 2025

.SYNOPSIS...
Rain is possible tonight into early Christmas Day, especially
south of Pittsburgh. Another storm on Friday brings a wintry mix
north and east of Pittsburgh and rain south of the city.
Temperatures remain above average through much of the week.

&&

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

- Rain chances increase south of I-80 overnight with passing low
  pressure
- Showers on Christmas Day morning with above normal
  temperatures
-----------------------------------------------------------

5AM Update...Updated the near term to better define the
instability and thunder present in a few storms this morning.
Mid level instability was enough to spawn a few thunderstorms
this morning and even require a warning back in Ohio. have
updated the pops through 18Z and added some thunder to the
grids. These storms will exit soon to the southeast. Also
changed the type to convective. Will expect a few showers
through the morning hours before the precip exits.

A weak upper disturbance embedded within deep-layer northwest
flow moves from the Midwestern CONUS to the Mid-Atlantic coast
tonight through this morning. Precip chances will continue to
increase through dawn. Expect weak warm advection through dawn
and into the day. In fact, some instability has been noted in
central OH and even a few rumbles of thunder. These ares are
south of the warm front setting up. Areas along and south of
this warm front should see near- surface and surface
temperatures remain above freezing, keeping the dominant precip
type all rain. Farther north, closer to the I-80 corridor, near-
surface wet bulb temperatures are more favored to hover around
freezing, which could support patchy instances of freezing rain.
Morning lows will fall into the mid/lower 30s across the area.

Rain showers will wrap up from north to south through the late
morning and into the afternoon with subsidence squashing the
moisture depth and forcing departing. Some may linger in the WV
ridges into the afternoon with upslope flow, but additional
amounts will be light. Lack of notable dry air intrusion will
keep clouds around for most of the day, but despite that and
northerly flow, afternoon highs will still be above normal in
the 40s and 50s.

&&

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

- Impactful winter system on Friday brings rain, snow, sleet, and
  freezing rain
- Winter Storm Watch in effect for counties north and east of
  Pittsburgh
- Dry weather returns briefly for Saturday
----------------------------------------------------------------

Another stronger shortwave will track across the lower Great Lakes
and track southeast in northwest flow into the Upper OH Valley. A
longer period of northerly component flow ahead of the low may allow
for colder air to be better entrenched ahead of it and open the door
for more wintry precip types. This still remains a tricky
forecast, especially for Pittsburgh metro and surrounding areas,
that will be highly dependent on the track of the surface low
and how far north the warm front reaches. Some wiggle room north
and south is still possible, and there are roughly three areas
to watch with this system:

1) US-422 and north, as well as into the PA ridges: This region
continues to be an area of at least moderate to high confidence.
Although recent runs of the NBM and associated members have
slowed the approached of the low as well as a slight shunt to
the north in the track. This has lead to onset occurring more
towards the middle to late period of the morning between 12Z and
18Z leaving the potential for warm air advection to engage
earlier potentially eating away at the freezing rain potential.
The known bias is the NBM`s favoritism to over due the WAA
leading to a potential impact to the surface temps. This in mind
combined with the fact that some members of the NBM still favor
a colder solution have made some adjustments to the ice
potential. Thus, the outer tiered counties such as Venango,
Armstrong, and the Fayette Ridges leave some uncertainty and
potentially too much to make the decision to upgrade on the mid
shift, thus left these regions within the watch. Its still worth
mentioning that even with the 01Z NBM run, the 75th percentile,
like the runs 24 hours ago still paint warning ice over Forest,
Clarion, and Indiana counties with little change in the impacted
area. These areas will still likely need a warning but another
dataset is needed for 80% confidence. Perhaps locations such as
the outer tier of the watches and locations like Mercer,
Butler, Armstrong, and Lawrence might require an advisory.

2) US-422 to I-70 (including Pittsburgh metro): This is where the
least confidence lies in surface temperatures owing to much
uncertainty in warm front placement and timing. Should it reach
farther north quicker and allow for above freezing surface temps to
filter in early, there would be minimal threat for ice and rather
just rain. Should the colder and slower southern placement verify,
there may be a period of freezing rain/sleet at onset before warm
air does eventually overtake and transition to plain rain. A lot of
guidance continues to suggest rapid WAA at the surface through the
morning hours, though this seems suspicious given stout east to
southeast flow at the surface which is not conducive of strong WAA.
In fact, downsloping effects (lowering Tds) with this direction
could even reinforce cooler surface temperatures with wet-bulbing to
the upper 20s/low 30s at precip onset. The 850 mb warm layer should
be safely through the area in the morning hours lending higher
confidence to snow being the least likely precip type. Can`t even
entirely rule out some thundersleet and/or thunder accompanying
freezing rain with fumes of elevated instability atop the low level
warm nose. Most likely onset timing is late morning, and the mid-day
timing is unlikely to have a significant effect on temperatures.
While warning criteria ice is unlikely in this region, a glaze to a
few hundredths of an inch is increasingly possible, so a Winter
Weather Advisory will likely be issued within the next 24 hours.
Given the uncertainty in the southwestern extent, as stated
above, will wait for one more dataset.

3) I-70 and south: This region should be safely in the warm sector,
even in a colder solution, and see the upper 50s to even low 60s for
highs with plain rain. Some thunder is possible here as well with
steep lapse rates atop the warm advection driven inversion. NBM prob
thunder highlights an elevated area in far SW PA and northern WV.

Transient mid-level ridging and brief surface high pressure should
return dry weather for Saturday. Temperatures will moderate
some with the increasing heights, but northerly surface flow
will still hold it back some with highs ranging from the 30s to
the north to the low 50s to the south.

&&

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

- Another system on Sunday followed by some lake effect snow
  potential early next week but with uncertainty
-------------------------------------------------------------------

A series of continuing shortwaves will provide periodic
precipitation chances into the weekend with the next system on
Sunday whose current track suggests less winter precip locally, but
uncertainty in positioning still exists. Longer range guidance
suggests a transition to some lake effect snow come the beginning of
next week in a deeper northwest flow pattern in the wake of Sunday`s
low. Exact amounts will be highly dependent on banding and residence
time as per usual, but the usual north of I-80 areas are likely to
see some accumulating snow. Even the current NBM 25th
percentile suggests an inch to two.

After the major shortwave passes the Upper OH Valley on Monday,
the rest of the forecast through Wednesday will feature a deep
northwest flow. Along this period will be numerous weak waves
within the flow along with an active lake effect set up. This
will keep snow showers in the forecast through the middle of
next week with a potential active/progressive pattern in place
through the end of the forecast.

&&

.AVIATION /10Z THURSDAY THROUGH MONDAY/...
KEY MESSAGES:

- Light rain with MVFR/local IFR restrictions S of I-80
- VFR returns by afternoon
- Restrictions and rain Friday, with freezing rain for FKL and
  DUJ
------------------------------------------------------------

Low pressure will track across the Ohio Valley region early this
morning, spreading areas of light rain and MVFR restrictions for
airports south of a FKL-DUJ line. IFR cigs are likely in closer
proximity to the low at ZZV and MGW. The cigs should scatter
out from N-S from mid morning through early afternoon as the low
exits and high pressure briefly builds in. Mid and high clouds
will then increase later today and tonight ahead of an
approaching warm front.

Outlook...
Restrictions and rain are expected for airports S and W of a
FKL-LBE line Friday as the warm front lifts north, though a
brief period of a wintry mix is possible at the precip onset.
FKL and DUJ are likely to see more predominant freezing rain
and icing potential. Precipitation should diminish from W-E
Friday night as the parent surface low crosses the Lake Erie
region, pulling a cold front across the area.

VFR should gradually return Saturday as high pressure builds in,
before an approaching low pressure system and cold front
returns rain and restrictions to the area Sunday. Gusty W-NW
wind is expected Monday behind the front, as rain changes to
snow.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...Winter Storm Watch from Friday morning through Saturday
     morning for PAZ008-009-015-016-022-074-076>078.
OH...None.
WV...None.

&&

$$

SYNOPSIS...Cermak
NEAR TERM...Shallenberger
SHORT TERM...MLB/Shallenberger
LONG TERM...MLB/Shallenberger
AVIATION...WM