Marine Weather and Tide Forecast for Chambersburg, PA

NEAR TERM /THROUGH WEDNESDAY/
A baroclinic leaf canopy of mid to high clouds continue to stream over most of central and southern PA this evening as a southern stream disturbance moves off the mid Atlantic coast through tonight. Sfc high pressure building from northeast OH late this afternoon will maintain fair and seasonable conditions tonight and Wednesday. Our forecast temps lean slightly cooler than NBM, particularly over the northern tier (using dewpoints as a floor) where areas of frost are most likely to form with min temps in the mid 30s. HRRR suggests this area is most likely to experience the best radiational cooling as high clouds peel away around daybreak.

SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/
Mostly sunny, warmer and rain free conditions expected into late week. Highs trend to the upside day over day with Thursday's maxT fcst to climb 10 to 20 degrees above the historical average into the 70-80F range. Nights will also be relatively mild for this time of year with a series of higher lows into the weekend. Increasing clouds on Friday and precipitation arriving in the west in the afternoon should keep temperatures in check somewhat, but highs should still get into the 70s areawide. Quite a week for springtime activities with sunset occurring around 8PM and ideal weather for being outside.

LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/
A surface low is currently progged to arrive Friday night as it crosses over the Great Lakes region into northern Pennsylvania.
This low, and the associated trailing cold front, is expected to bring widespread showers and thunderstorms into the region at the beginning of this extended period. Southerly gulf flow will bring a plume of moisture into the mid-atlantic region ahead of this system, providing ample deep moisture for afternoon convection on Friday. These showers will likely linger well into Saturday, with scattered thunderstorms associated with day time heating possible behind the cold front, before precipitation chances diminish into Saturday night.

Conditions are expected to dry out on Sunday with upper level ridging building in as the 500mb jet lifts to the northeast along with the associated short wave from Saturday. Temperatures will remain cooler on Sunday with highs expected to be in the mid 60s for most of central Pennsylvania. A warm up will then begin to occur Monday into Tuesday. 850mb temps will be well above 10C Tuesday, allowing for above average temps towards the middle of next week.

AVIATION /22Z TUESDAY THROUGH SUNDAY/
Few to scattered clouds are present over the airspace this afternoon. No flight restrictions are expected for the next 24 hours with mainly clear skies expected to continue overnight tonight. Winds this afternoon will be gusting out of the west up to 25kts. Tonight after sundown winds will gradually diminish and become calm.

Outlook...

Wed-Thu...No sig wx expected.

Fri...Showers developing during the afternoon with restrictions possible.

Sat...Showers and maybe a thunderstorm.

Sun...No sig wx expected.

CTP WATCHES/WARNINGS/ADVISORIES
None.