textproduct: Pittsburgh

SYNOPSIS

Morning cold front is expected to change lingering rain over to snow as temperature generally falls through the day today. Gusty wind that is strongest in the higher terrain will peak early this afternoon before subsiding.

Additional shortwave movement over the weekend will maintain below normal temperature with low probability precipitation. Temperature moderation and periodic rain is favored next week.

NEAR TERM /THROUGH TONIGHT/

KEY MESSAGES:

- Rain changing to snow through the morning post-frontal passage - Gusty winds expected along front and again during the late morning to afternoon - Wind Advisory and High Wind Warning in effect til Midnight -----------------------------------------------------------

A deeper upper trough axis that is beginning to tilt negatively as it approaches the upper Ohio River Valley region will push a notable surface cold front eastward this morning. Broad jet ascent ahead of the trough axis favors a swath of rain progressing east that could exhibit embedded enhancement courtesy of the additional lift along the front. Reaching eastern OH as of 1245am before exiting the region by 5am, this narrow band feature may accelerate strong winds aloft to the surface and cause localized/brief 40-50mph gusts as noted by a Special Weather Statement.

Areal precipitation coverage sharply declines by mid morning with the exiting surface cold front but remains possible given lift provided by the latter crossing upper trough axis. Lingering rain showers will transition to snow through noon as temperature falls behind the boundary; meager moisture profiles and warm/wet surfaces mean snow accumulation is generally limited to grassy surfaces and will be light (more on this in a moment). Two aspects are of concern for the rest of the daylight hours: 1) strong wind (due to tight surface gradient and mixed boundary layer) that will gust 25-40 mph in the lower elevations and between 40-55 mph in the higher elevations (and over 58 mph for eastern Tucker County. Wind Advisory and High Wind Warning headlines highlight higher confidence locations for impact/speeds that will decline tonight as mixing wanes. 2) CAA and orographic lift plus enough moisture may be enough for accumulating snow in the WV high terrain that could approach Advisory criteria. However, strong wind should keep SLRs closer to 10:1 (reducing modeling snow amounts) while warm surfaces limits early snow fall which may reduce overall impacts. Visibility impacts are likely, but confidence in greater impacts remain too low for additional winter headlines.

Crossing high pressure and subsidence characterizes the evening and overnight hours Friday, leading to diminishing snow showers and falling wind gusts. SW to NE clearing clouds plus cold advection means overnight lows will be around 5 degrees below normal.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/

KEY MESSAGES:

- Dry weather and moderating temperature Saturday - Frontal passage Sunday returns cool air but limited precipitation ----------------------------------------------------------------

Western Great Lakes troughing will aid in height rises with surface high pressure along the Atlantic Coast Saturday. Though moist advection aloft ensures increased cloud coverage, warmer southerly surface flow should aid in temperature moderation through the day while the region remains dry.

The shortwave trough will cross the area overnight Saturday into Sunday along with a surface cold front. Current model analysis suggests the frontal boundary is moisture starved and any precipitation may be tied to some Lake Erie enhancement amid cold advection and only impact northwest PA. Otherwise, the region's temperature will again fall around 5-8 degrees below the daily average with breezy winds that result in wind chill vales in the teens (northwest PA and higher terrain) and 20s (rest of the forecast region).

LONG TERM /MONDAY THROUGH THURSDAY/

KEY MESSAGES:

- Temperature moderation favors above normal temperature next week - Periodic precipitation chances in the form of rain -------------------------------------------------------------------

Ensemble model analysis strongly favors the development of ridging over the south central CONUS and the ridge axis extending into southern Canada; this places the upper Ohio River Valley on the eastern side of the ridge axis for much of the week.

It is a pattern that is highly correlated with rising temperature that will be comfortably above normal by Wednesday with further potential rises pending on ridge evolution eastward. The pattern also lends to little to no threats for impactful weather (via wind or wintry mix) varieties. The main discrepancies that create uncertainty is timing of embedded shortwave movements across the ridge axis that may portend to certain periods more likely resulting in generally light rain (or light snow if it crosses overnight) and the degree of warming experienced across the region.

AVIATION /06Z FRIDAY THROUGH TUESDAY/

KEY MESSAGES:

- Rain, restrictions, and gusty winds tonight with a passing cold front - Rain transitions to snow showers early Friday; gusty WSW winds continue throughout the day - Winds settle and VFR gradually returns to most areas over the weekend under building high pressure ------------------------------------------------------------

A swath of rain will continue to lift north as the cold front approaches from the west. Expect light rain and VFR conditions ahead of the front. As the night wears on ceilings will slowly drop to MVFR and IFR through the night. The northern terminals such as FKL and DUJ will see below IFR in the predawn hours. These restrictions will set in by 10Z at the other terminals across the area. The front will pass through by or just after dawn as rain changes to snow across the area. The snow showers will then persist on and off through the day with MVFR cigs or lower across the area. As the winds shift direction through the day, the snow shower potential will then come to an end. Much of the area is expected to be back to VFR by 00Z.

The only other concern will be the winds. Expect gusty winds through the period remaining southwest with gusts up to 30 knots and the shifting to the west by 11Z. Winds will continue to gust through the day.

Outlook... Patchy MVFR cigs may linger through the weekend mainly north of PIT in cold NW flow. VFR returns Monday under high pressure, before a warm front returns restriction potential for Tuesday.

PBZ WATCHES/WARNINGS/ADVISORIES

PA...Wind Advisory until midnight EST tonight for PAZ074-076-078. OH...None. WV...Wind Advisory until midnight EST tonight for WVZ512-513. High Wind Warning until midnight EST tonight for WVZ514.