Though I’m not much a fan of Keith Urban, that tune fits today’s forecast. The low-pressure system I was talking about on Wednedsay has arrived, a few hours ahead of what I had originally forecast but all in all, I only forecast twice a week so if I’m that close a few days out, I think I’m doing pretty well.

The first wave of rain already upon us as of Sunday morning will last at least through the morning. It is moving south to north and will exit Pennsylvania first before leaving New York in the early afternoon. An estimated quarter to half of an inch will fall before mostly drying out (with a few possible scattered showers) for the afternoon and evening.

After a brief break on Sunday afternoon and evening, the next part of this fairly strong (984 hPa) low will begin making progress toward the Twin Tiers. Rain should resume overnight headed into tomorrow. Somewhat surprisingly, this low has significant wraparound moisture, generally a trademark of weakening cyclones. As this low moves in a nearly direct eastward path across Pennsylvania, it will dump another half-inch of rain or so on the Twin Tiers over the course of Monday into Monday evening. By Tuesday, a cooler, drier atmospheric pattern will establish, allowing us to dry out but causing temperatures to fall several degrees below our average (average is 58 for April 27).

Sunday: Rain early, then clearing out. Afternoon highs in the mid-50s. A quarter to half inch of rain is expected.

Monday: Rain resumes before sunrise, ending by evening. Early morning lows in the low 40s. Afternoon highs in the low 50s. A half-inch of rain is expected.

Tuesday: Possible light drizzle early, but nothing of significance. Mostly dry, with a mix of clouds and sun. Early lows in the mid-30s. High temperatures in the upper 40s.

Wednesday through Saturday: The cooler flow will continue into Wednesday, leading to another day of upper 40s/low 50s, before an abrupt change in flow comes Thursday. Warm, moist air will begin coming upward from the Gulf of Mexico. Thursday will be very warm with temperatures in the upper 60s and no real threat of precipitation. Friday appears to be more complicated, as the GFS places the Twin Tiers on the edge of a very strong bullet of precipitation (2+ inches over southern Indiana) along the Appalachians. The Twin Tiers won’t receive the heaviest of this rain.

Long range: The GFS is being somewhat chaotic in regards to the solution for the long range, containing a broad and disorganized precipitation all the way up the Appalachians and to the Great Lakes. The good news in this is that the earlier forecast of warm (12-13 C) 850-hPa temps will appear to verify, which will lead to very warm temperatures upward to the upper 70s, perhaps even scraping 80 if there is enough clearing. With that in mind, I’m inclined to suspect that much of this projected precipitation is going to be of the convective variety Some time around next Monday, a low pressure will ride up the jet stream and bring a cold front with it along with some more organized showers. The 850-hPa temperatures for next Tuesday are forecast to be in the 4 C range, translating to temperatures in the lower 60s.

~J.M. Fuller