Area Forecast Discussion
Issued by NWS State College, PA
Issued by NWS State College, PA
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889 FXUS61 KCTP 032356 AFDCTP Area Forecast Discussion National Weather Service State College PA 756 PM EDT Mon Jun 3 2024 .SYNOPSIS... *Mainly dry the next 36 hours, with a stray afternoon shower or thunderstorm Tuesday. *More widespread rain on Wednesday afternoon and Thursday. *Cooler this weekend with scattered PM showers/storms. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... An isolated shower remains possible through early evening over Eastern Lancaster County and the Laurel Highlands, where satellite shows decent vertical cu development at 2330Z. Otherwise, expect scattered cumulus to give way to mainly clear skies after sunset. A nearly calm wind appears likely to promote late night patchy valley fog, primarily in the favored deep/river stream valleys of the Alleghenies. See no reason to deviate from NBM min temps, which range from the mid 50s in the coolest valleys of the NW Mtns, to the mid 60s across parts of the Lower Susq Valley. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/... Upper level ridging over PA should result in generally fair and warm weather Tuesday. However, diurnal heating may be enough to break through a weak capping inversion, resulting in isolated PM convection. Latest HREF suggests the best chance of a pulse-type shower/tsra will be along the ridgetops of Southern PA, where progged pwats are highest. Mixing down progged 850mb temps of around 15C translates to expected high temps in the low to mid 80s for most of Central PA Tuesday. An increasingly moist southeast flow ahead of an upstream warm front over the Ohio Valley may result in a isolated shower Tuesday night over Southern PA and will likely yield developing stratus per latest soundings. The next notable chance for rain arrives Wednesday afternoon, as a low pressure system drifting across the Great Lakes helps bring surging Gulf Coast moisture into the region. Southeast flow ahead of the approaching low pressure systems sets up a classic "cool" air damming scenario on Wednesday with persistent clouds and little to no instability ahead of the approaching warm advection lift. Temperatures will stay below 80 degrees everywhere except perhaps far northwest PA and could even struggle to get much above 70 at higher elevations. Latest suite of medium range guidance brings the warm front into southwest PA during the day on Wednesday with showers moving in Wednesday afternoon and evening. As mentioned before, instability will be lacking so not overly concerned about the severe weather threat on Wednesday evening. WPC has painted a big Marginal Risk across Central PA with the potential for some heavier downpours and localized rainfall amounts exceed 1 inch. Not overly concerned about flooding at this point given dry pattern lately and meager instability, but threat bears watching as hi-res guidance gets a better handle on the precipitation distribution and magnitude. By Thursday morning, most of PA will be in the warm sector, but without much forcing would not be surprised to see lingering light showers/drizzle Thursday morning. Cold front will sweep through sometime on Thursday and could generate a could stronger showers/storms as it sweeps through. Once the front moves through, the airmass will noticeably change with lower dewpoints and cooler temperatures aloft. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... The main weather feature for Central PA through next weekend will be a persistent cold core, upper low centered somewhere from the eastern Great Lakes region across southern Ontario and Quebec. As a result, at least hit and miss showers and thunderstorms are expected on a daily basis, with diurnally more numerous coverage anticipated in the afternoon and early evening hours, particularly for the northern tier of the Commonwealth. Current indications are that by early next week, the upper low should begin to fill and drift northeast, with showers and storms becoming less prevalent over time. Temperatures are likely to average somewhat below climatology for early to mid-June, with daily highs in the upper 60s and 70s, and overnight lows in the 50s to lower 60s. && .AVIATION /23Z MONDAY THROUGH SATURDAY/... 18z update... Now that ceiling bases have elevated early this afternoon, we anticipate VFR conditions through this evening, with a high degree of confidence (90+%). Most of our guidance is showing the redevelopment of lower clouds and fog later tonight into early Tuesday over the Alleghenies, as well as the ridge and valley region of central PA. For KBFD, KJST, KUNV, KAOO, and KIPT, we have fairly high confidence (60-80%) in fuel alternate-IFR restrictions. We expect gradual improvement after daybreak, with VFR returning area-wide after 15z. Outlook... Wed into Thu...More numerous showers and thunderstorms, with at least brief restrictions. Fri and Sat...Hit and miss afternoon showers and thunderstorms with brief restrictions, otherwise mostly VFR. && .CLIMATE... Prelim May and Spring 2024 Temperature & Precipitation Rankings Harrisburg: T12th warmest; 76th driest May T3rd warmest; 33rd wettest Spring Williamsport: 9th warmest; 22nd wettest May 4th warmest; 11th wettest Spring Altoona: 9th warmest; 13th wettest May 2nd warmest; 3rd wettest Spring Bradford: 4th warmest; 36th driest May Warmest; 21st wettest Spring && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Banghoff NEAR TERM...Fitzgerald SHORT TERM...Fitzgerald/Banghoff LONG TERM...Jurewicz AVIATION...Jurewicz CLIMATE...Steinbugl