Here is the latest Area Forecast Discussion for Central PA
This text statement is the latest forecast reasoning from the NWS in State College, PA
See the links at the bottom of the page for previous issuances/versions of the statement as well as our other text statements.
235 FXUS61 KCTP 301902 AFDCTP Area Forecast Discussion National Weather Service State College PA 302 PM EDT Wed Jul 30 2025 .SYNOPSIS... * Sweltering heat will close out one of the top-10 warmest starts to the summer season (June & July) on record. * Widespread thunderstorms are expected for Thursday and may lead to potentially significant flash flooding. * Significant pattern shift to deliver refreshingly cooler, less humid and rain free conditions to start the month of August. && .NEAR TERM /THROUGH TONIGHT/... Temperatures have climbed into the upper 80s and low to mid 90s across much of Central PA this afternoon, with many locations in the Lower Susquehanna Valley seeing heat index values exceed 100 degrees. The Heat Advisory remains in effect through 8 PM for the Middle and Lower Susquehanna Valley as well as for the south central Alleghenies. Isolated showers and thunderstorms have developed along the higher terrain and will continue through the evening before dissipating with the loss of daytime heating. With very weak shear in place, generally less than 25 knots, it will be tough for any individual storm to sustain itself. That being said, steep low level lapse rates and sufficient dry air aloft could support an isolated strong to severe gust with the strongest storms. A few showers will be possible overnight as flow turns southerly ahead of a cold front that will slowly sink southwards into central Pennsylvania. Low temperatures tonight will range from the 60s over the northern and western mountains, to the low to mid 70s in the southeast. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... *Elevated risk of excessive rain with some higher end flooding impacts possible across east-central/southeastern PA Thursday As the aforementioned cold front stalls near the Mason-Dixon Line on Thursday, all guidance shows a wave of low pressure developing along it and slowly tracking through the region. This will trigger widespread thunderstorms capable of producing heavy rainfall. The environment will be supportive of very efficient rainfall with PWATs around 2 inches, a warm cloud depth of 13000-14000 feet, and relatively weak flow oriented nearly parallel to the boundary. Most of the CAMs suggest the potential for rainfall amounts of 2 to 3 inches with localized amounts of up to 5 inches across the Lower Susquehanna Valley. Because of this, WPC, in collaboration with us and our neighboring offices, has decided to include a moderate risk (level 3 of 4) of excessive rainfall that includes York and Lancaster Counties. These areas may potentially see significant flash flooding impacts. Additional rainfall is expected farther north into the Middle Susquehanna Valley as a shortwave moves through well to the north of the surface boundary. There continues to be a zone of mid-level frontogenesis depicted in much of the guidance which should lead to an area of enhanced rainfall. While instability will be lacking in this part of the forecast area, it still seems possible for some locations to see as much as 2 or 3 inches of rain with this activity. We have issued a Flood Watch for both of these areas to highlight the potential for flash flooding tomorrow. Major changes in the temperature department for Thursday with highs 10 to 20 degrees lower vs. Wednesday across the northern 3/4 of the fcst area. Max temps range from the low 70s in the northern tier to mid 80s along the MD line. The refreshing air will make inroads into the northern half of the area by Thursday night, but it may take until early Friday to reach the southern part of the forecast area. Lows Thursday night will range from the low 50s in the NW mtns to mid 60s in the far southeast. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... A strong high with origins in Canada will move into the Northeast US and usher in a refreshing airmass, albeit somewhat slowly on Friday. Models continue to trend slower with the arrival of dry/less humid air, and we will have to maintain at least a slight chance of rain all the way up to I-80 into Friday morning. Another factor to consider will be the potential for gusty northeast winds as the surface low along the front deepens. Light rain, cloudy skies, and a northeast wind could make for a less than ideal start to Friday for southern PA, but eventually, clearing skies will work their way south. Much of the area will be firmly in the dry/cooler sector by Friday evening in the wake of the cold front. The comfortably cooler and refreshing airmass (much lower humidity) arrives just in time to begin the month of August. Slightly below average daytime highs 70-80F and lows 50-60F are forecast along with no rainfall through the first weekend of August. The dry spell and pleasant conditions (early taste of Fall?) should last into early next week with temperatures gradually increasing to near normal. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... At 18z, beginning to see some towering cu and isolated SHRA/TSRA pop up, mainly along and southeast of a line from IPT to UNV to JST. Expect this to continue through the afternoon and into this evening. A localized downpour and strong wind gust are possible. Lingering SHRA/TSRA activity should diminish after sunset. Locations that receive rain today could see the formation of patchy fog overnight. A frontal boundary will sag into southern PA on Thursday, with considerable cloudiness and more numerous SHRA/TSRA developing. Model guidance suggests that most locations should see cigs dip to near or just below 3 kft by Thurs aftn. Drier weather will return for Friday through the weekend. Outlook... Fri... AM SHRA linger over SE PA, with restrictions possible; trending drier with VFR conditions for the afternoon. Sat-Mon...VFR. && .CLIMATE... Record maximum temperatures for 7/30: MDT: 98 in 1940 IPT: 98 in 1933 AOO: 92 in 1983 BFD: 88 in 1999 STC: 97 in 1933 It has been a very warm start to the [meteorological] summer season which includes the months of June, July, and August. As we approach the end of July, here are the June + July average temperatures and "to-date" rankings for select sites in central PA: From June 1st through July 29th: Harrisburg: 76.7F average temperature ranks tied 7th warmest Williamsport: 74.0F average temperatures ranks tied 7th warmest Altoona: 73.0F average temperature ranks 3rd warmest Bradford: 67.7F average temperature ranks 2nd warmest State College: 73.0F average temperature ranks tied 6th warmest From July 1st through July 29th: Harrisburg: 79.7F average temperature ranks 9th warmest Williamsport: 76.8F average temperature ranks tied 9th warmest Altoona: 74.7F average temperature ranks 7th warmest Bradford: 69.6F average temperature ranks tied 4th warmest State College: 75.6F average temperature ranks 7th warmest && .CTP WATCHES/WARNINGS/ADVISORIES... Heat Advisory until 8 PM EDT this evening for PAZ019-025>028- 034>036-045-046-049>053-056>059-063>066. Flood Watch from Thursday afternoon through late Thursday night for PAZ028-036-041-042-046-049>053-056>059-063>066. && $$ SYNOPSIS...Steinbugl/Bauco NEAR TERM...Bauco SHORT TERM...Steinbugl/Bauco LONG TERM...Steinbugl/Bauco AVIATION...Evanego CLIMATE...Steinbugl/NPB |
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