Area Forecast Discussion
Issued by NWS State College, PA
Issued by NWS State College, PA
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252 FXUS61 KCTP 072201 AFDCTP Area Forecast Discussion National Weather Service State College PA 601 PM EDT Tue May 7 2024 .SYNOPSIS... - A warm front will drift northeast across the area this evening with scattered showers and a possible thunderstorm across southern PA. - Low pressure moves just north of the area tonight into Wednesday morning, brining showers and thunderstorms. - A stronger wave of low pressure will move across southern PA Thursday evening. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... A warm front will continue to track northeastward across central PA this evening, with scattered showers expected mainly along the spine of the Alleghenies and south of State College. SBCAPE values generally remains in the 500-1000 J/KG range with localized maxima across southern PA. Some elevated instability so have kept in a SChc of thunderstorms across S PA (Cambria/Blair southward) in showers this evening with highest chances across the PA/MD border in the next couple of hours. Temps did slightly overperform today, allowing for slightly warmer than forecast MinTs this evening with increasing cloud cover throughout the evening and overnight hours. MinTs will remain fairly uniform ranging from the upper 50s across the northern tier to lower 60s across the southern tier. Low pressure moves toward PA and western NY late this evening and will cross the area overnight. PWAT values topping out near 1.5" with an increase in CAPE will promote numerous SHRA/TSRA. It is of note that recent runs of hi-res guidance does indicate a slightly later arrival time with precipitation entering central PA after midnight. Models continue to outline that the area of greatest coverage remains across W PA in the 03-07Z timeframe overnight as the nose of a moderately strong, 35-45 KT LLJ approaches the region. Intense/near-severe storms overnight shouldn`t get much farther east than a BFD-UNV-AOO line. SPC has the SWrn corner of the CWA into the MRGL risk for svr wx as a cold front moves through the area. The period of showers and a few TSRA will peak between about midnight and 5 AM across Central and Eastern parts of the CWA. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... Model guidance tracks the weak surface low north of PA Wednesday, with a weak trailing cold front coming through during the morning hours. Any morning showers should give way to increasing sunshine, as drier air works in behind the front. Model 850mb temps near 15C support highs ranging from the mid- and upper 70s over the N Mtns, to the low and mid-80s in the valleys of Central/Southern PA. Mixed in lower PWATs via the NBM 25 pctl values for Wed afternoon as sfc dewpoints dive into the 40s (and possibly a few u30s across the Northern Mtns) during the late afternoon hours. && .LONG TERM /THURSDAY THROUGH TUESDAY/... While Wednesday will be mainly dry for much of the time, wet conditions work back into the area for Thursday. A sfc low still looks like it will track right along the PA, MD border. High temperatures for the most part will be below 70 degrees, and extensive cloud cover as well, will limit the chance for thunder. SPC has slight near the border in the far southeast. Storm development will depend on the track of the low and if much in the way of heating can occur during the day on Thursday. While rain will not occur all the time on Thursday or be very heavy, much of the day will feature at least some spotty rain and drizzle. While the low moves off the coast on Friday, cooling aloft will result in a chilly day, along with some showers. A brief break is likely for early Saturday, but another low drops southeast later on during the weekend, so looking at no real dry spells anytime soon. An upper level ridge building across the western states will aid in keeping more of the same type of conditions over our area into early next week. && .AVIATION /22Z TUESDAY THROUGH SUNDAY/... Most or all of central PA will see VFR conds continuing through early tonight with just some spotty, brief MVFR conditions in isolated SHRA. A warm front extending from KBFD to KUNV and KMDT at 1830Z will lift northeast across the remainder of the region late today/tonight. A potent upper level disturbance and sfc cold front will push east from the Ohio Valley later tonight and early Wed, preceded by a 4-6 hour period of LLWS late tonight and early Wed morning. This southwesterly low level jet causing the wind shear will also aid in the development of numerous showers and a few thunderstorms and a higher frequency of MVFR and brief IFR conditions, especially after 04z Wed. Drier air will begin to work into the western airfields around 12z Wed, but sfc fog may develop prior to sunrise as the low level moisture is slow to scour out. Outlook... Tue...AM low cigs/showers possible southern tier of PA. Scattered evening tsra impacts possible W Mtns. Wed...AM low cigs/tsra possible. Thu...Periods of rain/low cigs likely. Scattered afternoon TSRA. Fri and Sat...Showers with periods of low cigs possible. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...NPB NEAR TERM...Lambert/NPB SHORT TERM...Lambert/NPB LONG TERM...Martin AVIATION...Lambert