Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 242341 AFDCTP Area Forecast Discussion National Weather Service State College PA 741 PM EDT Wed May 24 2017 .SYNOPSIS... A storm over the TN valley will deepen and slide over PA on Thursday and up the New England coast Friday. Rain tonight and Thursday morning will be followed by scattered showers through Friday night. Saturday may be the best day of the weekend. The second half of the Memorial Day weekend looks wet with another storm system moving through the Great Lakes. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... Aside from a few small binovc over the North Central and Northwest Mountains, skies are solid overcast over central PA early this evening. Rain is advancing into the Laurel Highlands on the eastern periphery of a 30 to 35 kt 850 mb jet. The rest of central PA remains rain free at the moment. Between 00z and 06z...all but the Middle to Upper Susq River Valley should see rain...with some moderate rates over the Laurel Highlands and the Lower Susq River Valley in the pre dawn hours. Will leave out the mention of thunder for tonight, as llvl remains stable. Forecast precip amounts still on track with the 0.75-1 inch numbers still in the ballpark. The steadiest rain will be crossing the Mason-Dixon line around sunrise. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/... The rain will lift up northward through the morning. However, it looks to stay cloudy for another few hours. The southerly flow is not all that strong and may not help to scour out the low clouds very efficiently. Showers may again develop - esp if there will be breaks develop in the south. These would then rotate north in the aftn. But, for most folks there will be a brief break of just cloudy during the morning in the south and midday central and elsewhere. Again, if the low clouds hang around too long, the arrival of the upper energy will not line up with sun/instability. May be able to make some points on MOS by keeping temps down a notch or two in the south. The sky cover forecast for Thurs is pretty bleak, so we will hold maxes below guidance a bit. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... The strong upper trough will consolidate low pressure at the surface over PA producing a rainy Thursday night before lifting it up the New England coast Friday. Broad cyclonic/northwest flow with additional shortwaves rotating around the departing upper low will keep showers in the fcst on Friday before precip winds down Friday night/AM Saturday. A lower-amplitude mid level flow pattern in the wake of the departing closed upper low will feature rising heights/weak ridging aloft into the weekend. The pattern will evolve into a broadly cyclonic flow regime by early next week with upper low spinning between the Great Lakes and Hudson Bay into midweek. There is still some uncertainty regarding the location and timing of shortwave impulses that could be a factor for convection on Saturday. Model and ensemble guidance still favoring locations to the south/west of Central PA so a dry start to the holiday weekend may be in store for the area. Model blend maintains the highest POPs on Sunday with a risk for thunderstorms as well as a frontal system slides through. Another round of showers (storms SE) possible for Memorial Day, with sct showers poss lingering Tue into Wed as the parade of shortwaves around the trough continues into midweek. && .AVIATION /00Z THURSDAY THROUGH MONDAY/...
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MVFR ceilings have advected into my SWRN terminals in the strengthening SE flow. Regional radar shows a growing area of rain racing north out of the Virginias already affecting my SWRN areas and about to move into JST. Continuity and the HRRR show the rain continuing to overspread the region during the evening and into the wee hours of Thursday. Expect widespread MVFR/IFR to spread northward with the rain with all terminals seeing conditions lower between about 03-06Z. MVFR/IFR conditions will continue into the morning in the south and perhaps well into the afternoon in the north. Breaks associated with the dry slot will develop in the south in the morning as the steady rain pulls away. This will set the stage for some modest instability to develop leading to the chance for a thunderstorm in the afternoon. .OUTLOOK... Fri...Scattered showers with MVFR ceilings, mainly over western terminals. Sat...Mainly VFR with scattered rain showers. Sun...Reduced conditions with scattered showers/thunderstorms associated with a cold front. Mon...Mainly VFR with scattered showers/thunderstorms.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Dangelo/Steinbugl NEAR TERM...Dangelo/DeVoir SHORT TERM...Dangelo LONG TERM...RXR/Steinbugl AVIATION...La Corte is the U.S. government's official web portal to all federal, state and local government web resources and services.