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WHAT HAS CHANGED

* Freeze Watch issued for Friday night for Lancaster and Lebanon Counties.

KEY MESSAGES

1) Dry weather continues into the end of October.

DISCUSSION

KEY MESSAGE 1: Dry weather continues into the end of October.

A dry cold frontal passage this evening into tonight will barely be noticeable other than an increase in cloud cover along and behind the front. High pressure builds into the region again behind the front for tomorrow as a pronounced ridge develops over the eastern US. This will keep dry conditions around through at least the beginning of next week with seasonably warm days and chilly nights.

HREF probs of temperatures falling below freezing Friday night are around 50 percent for Lancaster and Lebanon Counties (the only zones where the growing season remains active). This is supported by the NAM MOS guidance which shows temperatures right around 32 in both of those counties. This information, combined with the very favorable set up for efficient radiational cooling, has given us enough confidence to issue a Freeze Watch for Friday night/Saturday morning.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

Outside of early morning river valley fog and areas of frost, expect solid VFR flying conditions for the vast majority of the time through the weekend and into next week.

A dry cold front will push south across PA later this afternoon and evening and bring an increase in the NNW wind with some minor gustiness into the teens (Central and West) and low 20s (KTS) across the Susq Valley and points East.

Later this evening and through the overnight hours, a SCT-BKN deck of post-frontal stratocumulus will overspread much of central Pennsylvania, with fewer clouds expected over the Lower Susquehanna Valley (KMDT/KLNS) as drier low-level air filters in overnight. The Northern Tier (KBFD) is moderately likely (40-50% chance) to see periods of MVFR ceilings through the night, with lower chances (mainly 15-25%) across the Laurels and central mountains (KJST/KAOO/KUNV/KIPT). Although this cloud deck may linger through the morning and bring intermittent MVFR ceilings over the southwestern airfields (KJST/KAOO) as the area of low-level moisture progresses southwestward, a return to prevailing VFR is otherwise favored.

CTP WATCHES/WARNINGS/ADVISORIES

Freeze Watch from late Friday night through Saturday morning for PAZ059-066.