Area Forecast Discussion
Issued by NWS State College, PA
Issued by NWS State College, PA
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272 FXUS61 KCTP 051612 AFDCTP Area Forecast Discussion National Weather Service State College PA 1212 PM EDT Fri Jul 5 2024 .SYNOPSIS... *Very warm and humid summertime pattern with above average temperatures continues into next week *Showers and thunderstorms are possible in spots today and Saturday followed by a rain-free end to the first weekend of July && .NEAR TERM /THROUGH TONIGHT/... Mesoanalysis shows broad but light cyclonic flow around a weak sfc low (1007 mb) located between KUNV and KIPT. This low was along an ill-defined, quasi stnry front near the I-80 corridor with a weak, lee-trough extending down through the Mid and Lower Susq Mainstem. Rich moisture with PWAT values between 1.5 and 1.9 inches across all but the Western Mtns of our CWA topped by sharp mid level ridging and a notable mid level cap with 700 mb temps of +9-11C has led to a mostly cloudy to cloudy morning so far with very little precip of note other than some stray light showers. We should see breaks in the cloud area slowly develop during the mid to late afternoon with isolated to widely sctd showers/TSRA developing, mainly across the Western Mtns. Convection will continue to form/advect from the west late today through early tonight (similar to the evening of the 4th, but perhaps just a bit greater in areal coverage). Previous... The latest hires guidance continues to favor a suppressed convective scenario for today - leaning bearish for t-storms and potential severe risk - with very limited development through the afternoon and into the evening hours. Early day cloud cover and shower activity (leading to reduced instability) appear to be the primary contributors. CAM signal remains consistent in ramping POPs higher across the NW zones closer to 00Z. CAPE and shear profiles are supportive of isolated severe t-storm potential with a large MRGL risk SWO covering most of the CWA. However, timing remains a wildcard and could end up being to late in the day/after dark. Another hot and humid summer day across CPA with highs in the 85-95F range. With the humidity (dewpoints 70-75F), it will feel like 100-102 degrees across portions of south central PA particularly in the lower Susquehanna Valley. Max HX values ticked higher above the century mark and we coordinated with WFO PHI on the issuance of heat advisory from noon to 8PM. A couple of showers/t-storm will could linger overnight which will be very warm and muggy with low temps 65-75F. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... Focus for t-storms will shift to the eastern periphery of the CWA on Saturday PM along and ahead of a weak cold front. Despite a very moist/unstable environment, most model guidance suggests limited storm coverage likely owing to neutral height falls and weak llvl convergence. That said, still can`t rule out a couple of strong t-storms over eastern PA. High pressure builds in Saturday night and provides a slightly less humid and dry (rain-free) end to the first weekend of July. && .LONG TERM /MONDAY THROUGH THURSDAY/... All medium range guidance supports fair weather and above average temperatures into early next week with upper level ridging indicated over the northeast. At the surface, high pressure is progged to build over Pennsylvania Sunday, then pass off of the east coast early next week. The return southerly flow should result in an uptick in heat/humidity early next week. Diurnally driven showers and thunderstorms appear possible on Monday based on recent GEFS plumes but guidance continues to suggest a better chance of precipitation on Tuesday with the arrival of a cold front during the afternoon hours. There is still a fair amount of uncertainty with regards to the cold front clearing eastern Pennsylvania later on Wednesday, so have retained PoPs through this timeframe. Towards the end of the period, deterministic guidance begins to outline high pressure influence into the region; however, given so much uncertainty earlier in the forecast period have opted not to deviate from NBM PoPs at this time. && .AVIATION /16Z FRIDAY THROUGH TUESDAY/... LLVL moisture pooling around a weak area of low pressure centered over the West Branch of the Susquehanna at midday will continue to create plenty of clouds through early this afternoon with areas of stubborn MVFR. Conditions will gradually improve to VFR in most places after 18Z. Isolated to scattered showers and thunderstorms will be possible again later this afternoon, though coverage looks to be initially more limited than what occurred Thursday. VFR will likely persist through much of tonight with the only restrictions coming in the form of a scattered shower or thunderstorm. Lower cigs could reintroduce restrictions by Saturday morning. Outlook... Fri...Sct TSRA w/ possible impacts; Mainly PM w/ highest coverage across the west. Sat...Sct to Nmrs TSRA areawide, highest chances SE in PM. Sun...AM fog possible; otherwise, no sig wx. Mon...SHRA possible SE late PM; otherwise, no sig wx. && .CTP WATCHES/WARNINGS/ADVISORIES... Heat Advisory until 8 PM EDT this evening for PAZ026>028-035- 036-056-057-059-063>066. && $$ SYNOPSIS...Lambert/Steinbugl NEAR TERM...Lambert/Steinbugl SHORT TERM...Steinbugl LONG TERM...Fitzgerald/Martin/NPB AVIATION...Lambert/Bauco/Bowen