CTP AFD
Confidence has increased sufficiently for Advisory issuances for parts of the Laurel Highlands (Somerset County) and the Lower Susq River Valley (Adams, York and Lancaster Counties), where 2 to 4 inches of snow is increasingly likely. Advisories may be expanded to include parts of the SC Mountains with a slight northward wag of the steadiest steadiest snow, but for now 1 to 2 inches appear likely across most of central PA south of I-80, with a coating to 1 inch likely over the north, through Friday morning. Even outside of headlines, the widespread light snow could lead to slippery travel into the Friday morning commute. As the precip moves closer to the near term range, HRRR and RAP models are indicating a slightly earlier onset time around late afternoon across the Laurel Highlands/southwest Alleghenies with snow expanding northeast to the I-80 corridor around 00Z/7PM. Expect period of accumulating snow from Thursday evening through Thursday night. The latest HRRR/RAP suggest the northern tier of CPA could see very little to no snow with a sharp northern precip gradient; while also showing some potential for moderate snowfall rates along the PA/MD border btwn 00-06Z Fri. Temps trend colder Thursday night with fcst minTs in the 15-25F range by daybreak Friday. Winds/gusts from the WNW should also be increasing into Friday morning with +single digit wind chills over the western Alleghenies. Synoptic snow should transition to lake effect snow showers Friday morning. Expect LES to last into Friday night with light to potentially moderate snow accumulation in the favored NW snowbelt. We were keen to increase POPs above NBM in the NW mtns, but later shifts may need to bump up snowfall amounts. Friday will be blustery with 25-35mph wind gusts and below normal highs trending 5 to 10F colder vs. Thursday. Lows will drop into the teens Friday night with winds subsiding by AM Saturday.