476
FXUS61 KPBZ 170600 AAC
AFDPBZ

Area Forecast Discussion...UPDATED
National Weather Service Pittsburgh PA
100 AM EST Mon Nov 17 2025

.SYNOPSIS...
Lake-effect snow is expected north of I-80 tonight into Monday.
Another passing system brings a rain/snow mix Tuesday.
Temperatures rise midweek before rainfall returns late-week.

&&

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

- Gusty conditions through tomorrow; Wind Advisory for eastern
  Tucker
- Lake effect snow north of Pittsburgh tonight into tomorrow;
  winter headlines in effect

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Advancing cold air from the northwest late tonight into Monday
will enhance the potential for lake-effect snow showers across
parts of the region.

Rain has changed over to snow for most locations with a
continuation of cold advection plus the loss of diurnal heating.
The expectation is for a consolidation of scattered snow showers
across northwest PA into a more narrow band of increasingly
heavier snow (with a few isolated showers around its periphery)
as lake effect processes become the dominant forcing mode given
NW flow with -8 degrees Celsius temperature at 850mb. With a
steady fetch off Lake Huron and Erie, high- resolution model
guidance continues to show this narrow band of heavy snow
pushing into the vicinity of Forest County after dark and
persisting into early Monday morning. Given the higher
probability of heavier snow in Forest County, a Lake- Effect
Snow Warning is in effect for snow accumulations between 6 to
10 inches, with up to 12 inches a still low possibility.
However, localized higher amounts (up to a foot) can`t be ruled
out. Initial accumulations may favor elevated surfaces and
grassy areas due to residual warm, wet conditions on area
roadways, but increasing snow ratios (approaching 15:1) and
falling temperature should allow for accumulations on all
surfaces by midnight.

There is potential for the snow band to drift west and south of
Forest County at times, which supports the Winter Weather
Advisory currently in effect for Clarion, Jefferson, and Venango
counties. However, if the band lingers over any of these areas
for an extended period, an upgrade to a Lake-Effect Warning may
become necessary.

By early Monday afternoon, a slightly westward shift in the
boundary-layer wind pattern over the Great Lakes will likely
cause the heavy snow band to weaken or drift north/northeast
effectively ending the threat for significant snow.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
KEY MESSAGES:

- Dry and quiet Monday night
- Another system crosses the region Tuesday returning a
  rain/snow mix
----------------------------------------------------------------

With a ridge building from the west late Monday into early
Tuesday, expect quiet and dry conditions. Overnight temperatures
will trend below average due to clearing prompting radiation
cooling and linger cold air aloft.

After sunrise on Tuesday, a new disturbance is expected to move
out of the northern Plains and into the Ohio River Valley,
bringing precipitation chances back to the region. There is a
chance that precipitation will begin as snow, with lingering
low and mid-level dry air supporting cooling aloft through wet-
bulbing. Given temperature profiles at peak saturation hovering
near freezing, any snow that does develop will likely be wet
and heavy and limit amounts. By late morning or early afternoon,
all precipitation type will likely switch to rain with warm
advection. Rainfall amounts will be considered light, ranging
between a tenth of an inch to a quarter of an inch. Localized
higher amounts may be measured in the ridges of West Virginia
due to upsloping.
 is likely to continue.
&&

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

- Above average temperatures into next weekend
- Rain chances rise again late week with another passing
  disturbance likely
-------------------------------------------------------------------

Ensembles continue to agree overall on rising 500mb heights during
the second half of the work week, leading to temperatures rising
above normal, and decidedly so by Friday. Despite the ridging aloft,
low pressure traversing the Lower Ohio Valley may spread weak
inverted surface troughing further downstream, supporting some low
chances of light rain Wednesday night and Thursday.

Thereafter, the majority of ensemble members favor a shortwave
trough riding from the Central Plains northeastward towards the
Great Lakes on Friday. Strength and timing issues do remain among
the various solutions. In any case, increasing moisture on southwest
flow seems to favor increasing rain chances Thursday night with the
approach and passage of a warm front, followed by a cold frontal
passage during the Friday/Friday night period. Showers may linger
into at least Saturday in post-FROPA northwest flow, before a drier
trend may return by Sunday. At this time, temperatures look to
remain near to just above normal even behind the front, with most
ensembles keeping 850mb temperatures above zero. So, a return to
wintry precipitation next weekend is not favored at this time.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
Lake effect snow showers will continue north of I-80 this
morning. Most ports are expected to remain VFR, but KDUJ may see
MVFR restrictions with snow given it`s proximity to possible
snow band positions. It`s not a zero percent chance KDUJ could
observe IFR/LIFR conditions in poor visibility, but confidence
at this time is too low to included in the latest TAFs.

With a tight pressure gradient, expected wind gusts to range
between 25 to 35 kts today.

Outlook...
Lake effect snow band(s) will diminish by this evening under
increasing subsidence.

Periodic restriction and precipitation chances are expected
throughnext weekend as the area remains under a relatively
active weather pattern.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...Winter Weather Advisory until 1 PM EST this afternoon for
     PAZ008-015-016.
     Lake Effect Snow Warning until 1 PM EST this afternoon for
     PAZ009.
OH...None.
WV...Wind Advisory until 10 AM EST this morning for WVZ514.

&&

$$

SYNOPSIS...Hefferan
NEAR TERM...Hefferan/Frazier
SHORT TERM...Hefferan
LONG TERM...CL
AVIATION...88