textproduct: Pittsburgh

SYNOPSIS

Near-normal temperatures are generally favored this week, save a few day-to-day fluctuations above average. Light rain chances increase north of Pittsburgh late Wednesday, with more substantial rain chances on Friday on a cold front with a potential cooldown thereafter.

NEAR TERM /UNTIL 7 AM MONDAY MORNING/

KEY MESSAGES:

- Dry with decreasing clouds - Lingering clouds early tonight could result in above average low temperatures.

---------------------------------------------------------------

Upper-level subsidence will aid in decreasing cloud fractions into the overnight hours, however, there is some uncertainty in this. Should clouds be maintained longer, temperatures may remain above average overnight. In the event they clear as forecast, a calm night with average low temperatures is favored.

SHORT TERM /7 AM MONDAY MORNING THROUGH TUESDAY NIGHT/

KEY MESSAGES:

- Low probability light showers along / sprinkles north of I-80 Monday - Dry and seasonable conditions persist otherwise. ----------------------------------------------------------------

A fast-moving shortwave will cross the region Monday afternoon and push a weak surface cold front through the region during the afternoon along with an associated moisture-starved front. The frontal boundary result in little more than a wind shift (veering to the west) and slight uptick in clouds, but enough cold advection at 850mb could create a lake- enhanced shower that skirts areas north of I-80. Any precipitation that falls will be short-lived, very light, and result in little, if any, measurable rain. Otherwise, near normal temperature with breezy afternoon winds will characterize the day.

Strong surface high pressure developing south of the region underneath quasi-zonal flow (slight NW angle though) portends continued dry weather for Tuesday. Subtle cool advection will knock area readings down a degree or two from Monday but still be near the daily average.

LONG TERM /WEDNESDAY THROUGH SUNDAY/

- Next system arrives Wednesday afternoon into Thursday morning, with variances on southern extent of precipitation field. - Active pattern hints at potentially deeper trough development heading into the next weekend. -------------------------------------------------------------------

Fast shortwave movement out of the Pacific northwest is expected to enter the Great Lakes region Wednesday afternoon/evening through Thursday morning. Ensembles strongly favor the trough center remaining north of the region but vary in the degree of depth (with nominal timing variances), which will play a major role in the southward extent of precipitation chances. The speed of movement and high likelihood of marginal cooling aloft/behind the surface front minimizes the risk of developing winter precipitation types while keeping rainfall accumulations low (current data suggests only 15-30% probability of totals exceeding 0.25").

The brief cooldown Thursday is likely to feature dry weather as high pressure returns underneath brief shortwave ridging. Ensembles suggest the pattern remains active thereafter with additional shortwave movement creating periodic precipitation chances starting Friday. However, cluster analysis suggests that variations in trough depth as well as timing suggests a more unclear picture for exact timing of future precipitation periods and degree of cooling (plus any potential temperature rebound). It is unlikely any scenario will feature headline-worthy weather, but a mention of higher elevation snow (low accumulation) could enter the discussion late in the weekend into the following week.

OUTLOOK

High pressure will continue to support high confidence (>80% chance) of VFR through at least mid week. A weak disturbance brings rain chances back to the area Wednesday into Thursday, but confidence in any associated restrictions impacting area terminals remains low at this time.

PBZ WATCHES/WARNINGS/ADVISORIES

PA...None. OH...None. WV...None.