Weather forecasts: heat then rainy Memorial Day

PennLive and Greenville News reported this week that forecasters in Pennsylvania and South Carolina expect a sharp turn in weather before Memorial Day weekend. Central Pennsylvania was forecast to reach 95 degrees on Tuesday and 91 on Wednesday before a cold front pushes temperatures down and brings rain, PennLive reported. In South Carolina, the Greenville-Spartanburg office of the National Weather Service said a cold front would stall nearby through the weekend, producing cooler and wetter conditions after recent heat and drought. The holiday setup leaves two of the East Coast’s busiest late-May travel corridors facing a mix of heat, thunderstorms and then unsettled weekend weather. ### How fast is the weather changing in Pennsylvania? Central Pennsylvania was forecast to swing from near-summer heat to a cool, rainy holiday stretch in a matter of days. PennLive reported temperatures could reach 95 degrees Tuesday and 91 Wednesday before a cold front arrives. The National Weather Service in State College said in a May 20 regional summary that a cold front moving southeast from Lake Erie would trigger scattered showers and a few strong thunderstorms across Pennsylvania on Wednesday. (pennlive.com) The office also said the early-season heat wave would break down as the front moves through. A State College forecast discussion issued early Wednesday said forecasters were increasing the odds of a “noticeably cooler and rather wet” start to Memorial Day weekend and trimming expected high temperatures for Friday and Saturday. (pennlive.com) ### What are South Carolina forecasters saying about the holiday weekend? Greenville News reported that South Carolina forecasters expect showers and thunderstorms over Memorial Day weekend after a stretch of heat and drought. (weather.gov) The paper said the outlook could force changes to outdoor plans in parts of the state. (preview-forecast.weather.gov) The National Weather Service office in Greenville-Spartanburg said a cold front would approach on Wednesday and then stall nearby through the weekend, resulting in cooler and wetter weather through Memorial Day weekend. The office said the threat for severe thunderstorms and excessive rain appeared low at that point. The Greenville area point forecast showed a 40% chance of showers and thunderstorms Wednesday afternoon and a 60% chance on Thursday, with highs near 90 both days before the wetter pattern settles in. (greenvilleonline.com) ### Is this just a rain forecast, or a bigger pattern shift? National Weather Service forecast discussions in both regions pointed to the same broad setup: heat ahead of a front, then cooler air and repeated chances for rain behind it. (forecast.weather.gov) In Pennsylvania, the State College office said highs over the holiday weekend were likely to fall into the 60s with widespread rain, according to PennLive’s account of the forecast. (forecast.weather.gov) In the Carolinas, the Greenville-Spartanburg office said the front was expected to stall, a pattern that can keep clouds and periodic showers in place for several days. The office said low clouds and a more active pattern for afternoon and evening showers and thunderstorms were expected to continue through the end of the week. (pennlive.com) ### What does this mean for Memorial Day plans? Memorial Day travelers in Pennsylvania and South Carolina are likely to face two different weather problems in the same week: heat before the holiday and wet conditions during it. The Pennsylvania forecast points to hot temperatures and a chance of strong storms before a cooler, rainier weekend, while the South Carolina forecast points to repeated shower and thunderstorm chances after near-90-degree highs. (forecast.weather.gov) Outdoor events, road trips and beach or lake plans could be affected most from Friday through Monday, based on the current forecast windows cited by local outlets and National Weather Service offices. Forecasters in both regions said updated timing and rainfall totals would depend on how quickly the front moves and where it stalls. That is an inference from the forecast discussions describing an approaching front in Pennsylvania and a stalled boundary in the Carolinas. (weather.gov) ### Where should readers look next for updates? The National Weather Service offices in State College and Greenville-Spartanburg were updating forecast discussions and local forecasts on May 20 as the front moved closer. PennLive and Greenville News both framed the forecast as likely to evolve as the holiday weekend approaches. Thursday, May 21 and Friday, May 22 are the next key forecast checkpoints, when local offices are expected to refine rain timing, thunderstorm chances and holiday weekend temperatures for Pennsylvania and South Carolina. (preview-forecast.weather.gov) (weather.gov 1) (weather.gov 2)