After a string of breezy, chilly days that we’ve dealt with for the first part of the week, the Twin Tiers region appears to be on track for some much warmer weather as the weekend approaches. While today and tomorrow will be primarily sunny, the same may not be said about Saturday and Sunday as rain is expected to develop in the area.

Thursday: Mostly sunny. Afternoon high temperatures in the low 60s. Some breezy winds dying down by evening as clouds move in.

Friday: A mix of sun and clouds. Significantly warmer. Early low temperatures in the upper 30s. High temperature in the mid to upper 70s.

Saturday: Getting downright sticky. Early low temperatures dropping only to the upper 50s. High temperatures again reaching the upper 70s. Light precipitation is likely, less than a tenth of an inch.

Sunday through Wednesday: The more intense rain showers seem to be most likely to develop on Sunday, with rain moving in from south to north and those in Pennsylvania being first to get the most intense precipitation. Those in the most intense precipitation belts could receive upward of an inch of precipitation. This wave of rain should exit over the course of the day Monday as the cold front swings through. Behind the cold front, temperatures will likely reach the low 60s for afternoon highs. Beginning Tuesday night and leading into Wednesday, the GFS is forecasting a low pressure system to cross over the Great Lakes, bringing with it some light but persistent rain showers that could last into Wednesday. If this verifies, the temperatures will also take a significant hit, as an upper level low will push 850-hPa temperatures down to the -4 C range, translating to high temperatures only into the upper 40s– a dreary midweek to be sure. However, the ECMWF model is forecasting a much different solution that keeps the area in a much warmer flow and is not as eager to propagate the large wave in the jet stream eastward. If the ECMWF verifies, that low will stay over Manitoba (far enough away not to influence the Twin Tiers) and temperatures at the 850-mb level don’t even drop to +8 C, which would indicate temperatures continuing into the 70s. Which one is more trustworthy? It’s hard to say. For now I’ll split the difference and predict temperatures near normal in the 60s. When I do the next forecast, probably on Monday, I’ll take a closer look at how much the models have converged since that point.

Long range: By next Thursday or Friday, the GFS’s brief shot of northerly flow will have broken up in favor of a light westerly zonal flow. The GFS is painting in another low (and thus more rain) forming during this time but at this point I’m not all that confident of that. All in all, expect relatively normal temperatures (i.e. low-60s) for next weekend.