Freezing rain to convey journey points for elements of Pittsburgh space Friday | First Alert Weather

An ice storm warning has been issued till 7 a.m. Saturday for Somerset, Westmoreland (ridges), Indiana, Armstrong, Clarion, Jefferson, Forest, and Venango counties.

A climate advisory consists of Allegheny, Beaver, and Washington till 3 p.m. Friday, and a winter climate advisory consists of Preston, Fayette, Westmoreland, Butler, Lawrence, and Mercer counties till 1 a.m. Saturday.

First Alert: Friday Ice storm for elements of Pittsburgh viewing space; monitoring subsequent Monday as nicely.

These advisories expire primarily based on the time when temperatures are most probably to be safely above freezing, and or precipitation has ended. 

We are nonetheless on observe for a blended bag of precipitation to maneuver on Friday morning between 8 a.m. to 12 p.m. Not a lot has modified from earlier discussions relating to precipitation sort expectations. The preliminary wave will seemingly start with a interval of sleet and maybe a number of flakes, then transition to freezing rain and rain because the depth of heat air within the ambiance expands with an approaching floor low-pressure stress. 

Over the final 12-24 hours, there was a slight northward nudge within the anticipated observe of the floor low, which raises confidence {that a} majority of the Pittsburgh metro will solely have a short window for freezing rain earlier than switching over to rain by mid-afternoon Friday. Ice quantities will vary from a glaze upwards to a couple hundredths of an inch, with no tree or powerline injury anticipated. An untreated floor could also be slippery for a few hours, however temperatures are prone to heat above freezing.

Farther north towards Highway 422/I-80, that is the place temperatures might be beneath freezing a lot of the day, supporting an extended length of freezing rain and sleet, and ice accumulation. Ice quantities upward of 0.25″-0.4″ are seemingly right here, and this may increasingly trigger minor injury to bushes and energy traces. 

Any untreated surfaces might be coated in ice, together with roadways, which can make for troublesome journey. Some areas alongside the I-80 hall, particularly east of I-79, could keep beneath freezing for all the length of the occasion. The identical will be mentioned for the Laurel Highlands, particularly the eastward slopes and valleys which might be extra prone to maintain onto the shallow, subfreezing layer of air on account of chilly air damming. 

Areas southwest of Pittsburgh are anticipated to obtain all rain, and areas the place the floor heat entrance passes, afternoon and night temperatures will attain the low to mid-50s. 

This system will exit on Saturday, leaving us with a largely cloudy and seasonable day with highs typically within the higher 30s to low 40s. Another sturdy storm system will arrange to the west on Sunday and pressure a heat entrance into the area Sunday morning and early afternoon. 

Temperatures will attain the low-to-mid-50s late within the day Sunday and probably some areas close to 60°F earlier than the chilly entrance passes Sunday night time into Monday morning. 

Widespread rain and probably some thunderstorms are anticipated with this technique. This system may have a reasonably excessive quantity of atmospheric moisture by December requirements, so heavy rainfall is feasible spots. 

Temperatures will shortly fall behind the entrance by way of the day on Monday, with rain altering to snow. Monday’s setup might probably contain a flash freeze if temperatures drop quick sufficient, and relative humidity stays elevated behind the entrance.