Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 231813 AFDCTP Area Forecast Discussion National Weather Service State College PA 213 PM EDT Fri Jun 23 2017 .SYNOPSIS... The combination of an approaching frontal system and the remnants of Tropical Storm Cindy will funnel a plume of deep tropical moisture into the region today and tonight. The cold front will push east across the region during the morning or early afternoon hours Saturday, followed by drier and cooler air with comfortable humidity that will last through much of next week. && .NEAR TERM /THROUGH TONIGHT/... The first wave of rain is still falling on much of the Central and Northern Mountains. RAP shows CAPEs nudging upward over southern PA as the leading edge of the real soupy PWAT air starts to surge into the NERN US. Analysis shows PWATs exceeding 2" (2-4 sigma) in a wide swath from the Louisiana Gulf Coast up into eastern Ohio and western PA, and moisture transport vectors are all pointing the plume right toward our CWA. While much of the late morning into the mid afternoon will end up with off and on showers over most of the region, by mid to late afternoon a more substantial area of rain will develop/advect into the area as the best moisture associated with the remnants of Cindy, over far SERN Missouri at 12Z, begins to affect the forecast area. From earlier... Kept temps close to Superblend/National Blend...ranging from the low 70s over the northwest mountains, where overcast skies are expected, to the mid 80s over the Lower Susq Valley, where model RH profiles support partly sunny skies by afternoon. && .SHORT TERM /SATURDAY/... *Heavy rain and short-term flooding risk Friday-Friday night. Local heavy rain threat will last into tonight, but confidence not sufficient for a Watch at this time. Deep tropical moisture (PW locally 2"+) associated with the remnants of TS Cindy will combine with the approaching northern stream trough and cold front to bring a slightly elevated risk of locally heavy rainfall and potential flooding to portions of central PA. Factors arguing against a Watch at this time are fairly narrow window of heavy rainfall and general longer duration of 2"+ rainfall totals...occurring over a 12 hour plus timeframe. If one area has a greater risk of minor would be the Laurel Highlands where a multi- model blend incorporating HIRES models/CAMs remains fairly consistent with location of max QPF. Enhanced terrain lift will also be a factor over a region that has the lowest ambient short-term FFG in the CWA. HWO continues to highlight lower end +RA/FF risk at this time - later shifts should consider a FF watch at shorter ranges with increasing confidence. Heavy rain threat winds down late tonight as deepest subtropical moisture is shunted east of the region after midnight. Expect lingering moisture/rainfall associated with the moisture remnants of TS Cindy to exit the area by Saturday afternoon. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... From a large scale perspective, the medium range forecast will feature a seasonably strong/amplified upper trough settling over the Northeast U.S into next week. The theme continues to be above avg confidence in the pattern but low confidence in the details. Drier, low PW air arrives behind the cold front later Saturday with decreasing clouds and lowering humidity providing a nice start to the weekend. An extended period of comfortable, low-humidity conditions with temperatures near to below late June climatology are expected to last through the early part of next week. A few cool nights early next week with min temps 40-55F. Precipitation opportunities will be modulated by shortwave impulses reflecting weak surface fronts/troughs which have low predictability at this range. Any pcpn would be generally scattered in nature and on the light side given below normal moisture levels for late June. The 22/12z GEFS shows PW values remaining below average through midweek which would tend to favor mainly dry wx. Temperatures should stay on the cooler side of climo through midweek as the upper level trough shifts east of the area. Differences continue with the trough evolution later in the week with the GFS initially more amplified before building SE U.S. ridge. The EC generally maintains a mean trough over the Northeast CONUS into the second half of next week. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
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Widespread MVFR/IFR remains in place across central PA this aftn, as the remnants of TS Cindy make their way across the area. Showers are moving in from the west, some with locally heavy downpours and sudden reductions in vsby. Thunderstorms should develop as well, especially across srn PA where the sun has come out. Storms may contain gusty winds. Showers/storms will persist into this eve and tonight, with localized downpours remaining likely. This will result in significant reductions in both vsbys and cigs. Gradual improvement to VFR is expected area-wide on Saturday, as the system pulls east of the region. .OUTLOOK... Sat...Scattered restrictions in AM showers...otherwise becoming VFR. Sun...Mainly VFR. Mon-Tue...Mainly VFR, but with a chance of SHRA/TSRA. Tue...VFR.
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&& .EQUIPMENT... KCCX radar will be offline for approximately 4 days starting Saturday, June 24th for technicians to install the first of 4 major service-life extension upgrades. The work on the radar has been scheduled to minimize potential impacts to operations and will be delayed if hazardous weather is forecast. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...La Corte NEAR TERM...La Corte SHORT TERM...La Corte LONG TERM...Steinbugl AVIATION...Evanego EQUIPMENT...Lambert is the U.S. government's official web portal to all federal, state and local government web resources and services.