Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 221816 AFDCTP Area Forecast Discussion National Weather Service State College PA 216 PM EDT Thu Jun 22 2017 .SYNOPSIS... A warm front will move through the region today, bringing a return to warmer and much more humid conditions this afternoon right through Friday night. A 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/... An area of showers and thunderstorms extends from east of BUF down into NERN Ohio. The HRRR takes this ESE across the area mainly north of I-80 through late afternoon before depicting it as becoming more scattered and disorganized. Dewpoints have surged into the mid and upper 60s rather quickly with the approach and passage of the diffuse warm front. We will stay in the soupy airmass for at least the next 36-48 hours before drier air returns to the region. SPC has much of the northern portion of the region under a Marginal Risk. Instability in the area of the Marginal Risk is limited at best as of mid day, but model guidance does show the development of at least moderate CAPE and shear over much of the western part of the state as the afternoon warms up, and with dewpoints climbing this looks reasonable. RAP depicts 0-1km EHIs between 1 and 1.5 m2/s2 across much of the NW part of my CWA into the evening, so the potential exists for stronger storms to rotate. SPC addressed the convection developing over the area and this tendency for rotation, but at this time a watch is not likely. The biggest threat over the next 36-48 hours will be for heavy flooding rains as we see an almost classic set up for a PRE event developing over the NERN US. Any localized heavy showers and thunderstorms today will lay the groundwork/lower FFG values and additional and potentially training convection that will occur Friday through Friday night as moisture from Tropical Storm Cindy surges into the NE US. Moisture will continue to increase ahead of the remnants of TS Cindy that are surging NE out of the Gulf States. PWATs are forecast to increase to between 1-4 sigma by daybreak Friday and continue into Saturday morning. By late tonight rain and embedded heavy thunderstorms should be overspreading my southern zones. Any decision on Flood Watches will be made by later shifts. && .SHORT TERM /FRIDAY/... Friday into Friday night will be the most active weather period of the next 7 days as increasing large scale lift/vertical shear ahead of a potent northern stream trough interacts with the deep tropical moisture and high PWAT air in place across the state. WPC has a Slight to Moderate Risk of heavy flooding rains for our entire forecast area. The set up is pretty much right out of Junker`s heavy rain manual with tropical moisture getting funneled up into the westerlies and into what is forecast to be a large jet entrance region from the the Midwest into the eastern Gr Lakes. Basin average rainfall for the 48 hour period today through early Saturday calls for widespread amounts of an inch of more, with SWRN areas seeing between 1.5 and 2.25 inches. Training showers and storms in this moisture rich environment (PWATs well in excess of 2") could quickly increase the Flash Flood potential Friday into Friday night. && .LONG TERM /FRIDAY 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. Expect moisture/rainfall associated with the remnants of TS Cindy to exit the area by the mid to late morning hours Saturday. Drier, low PW air arrives for the late morning and afternoon hours Saturday and lasts through the weekend. This should translate into comfortable, low- humidity conditions with temperatures near to slightly below late June climatology. Precipitation opportunities will be modulated by several shortwave impulses which have low predictability at this range. Any rains would be generally scattered and on the lighter side given overall lack of deep layer moisture. 21/12z GEFS shows PW values remaining below average into midweek. Temperatures should stay on the cooler side of climo through midweek as the upper level trough shifts east of the area. FWIW the GFS is more bullish vs. EC on heights rebounding/building SE U.S. upper ridging into the second half of next week. That said, there is general agreement in a modest warming trend later next week as the trough moves out and heights return to normal. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... Widespread VFR exists as of 18Z. An area of showers/thunderstorms is dropping ESE through the northern mountains. BFD will be the most likely to experience brief reductions as the convection affects the airfield. Elsewhere VFR will continue into the evening with hit and miss showers and storms causing localized reductions. There will be a better chance for more widespread IFR conditions to develop tonight and tomorrow as rain and embedded thunderstorms from the remnants of TS Cindy overspreads the region. .OUTLOOK... Sat-Sun...Mainly VFR Mon-Tue...Mainly VFR. Chc SHRA/TSRA. && .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...Lambert/Steinbugl AVIATION...La Corte EQUIPMENT...

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