ITHACA, N.Y. — Early spring tends to be rather tempestuous in Upstate New York, and this year will be no exception. A broad, multi-faceted storm complex will bring several days of rain and possible wet snow to Ithaca and its environs this week, but once the system clears out by late Friday, a rather tranquil weekend is in store for Tompkins County. Placid weather cis likely to continue into Monday, when throngs of visitors will be passing through to points north and west to see the solar eclipse.
Your Weekly Weather
Two broad if diffuse areas of high pressure from Canada and the Southeastern U.S, are in place this Easter Sunday, with a developing storm system over the Great Plains. A weak shortwave (pulse of instability) provided some grey skies this morning, and the cloud cover overhead should thin out somewhat as the day goes on and the shortwave moves east. By sunset, clouds will once again build up as the storm system develops to the southwest. Highs will be seasonable for this final day of March, with highs in the low 50s. March is going out like a lamb – an Easter lamb, as it were. Sunday night will see skies become overcast with lows in the upper 30s.
The warm frontal boundary associated with Great Plains low appears likely to stay south of Tompkins County Monday. However, a shortwave will ride along the frontal boundary, which will serve as a channel of instability to transport the shortwave eastward. Some rain showers are likely to spread across the region, especially south of Ithaca. The rain would primarily be in the morning, with a few scattered showers in the afternoon as the short wave heads east. Highs will be in the low 50s, and new rainfall amounts will generally be <0.1″. As the low moves into the Ohio River Valley Monday night, the front will approach and showers will one again spread across Tompkins County after midnight. Lows will be around 40, and new rainfall amounts will once again be light, <0.1″.
Tuesday shows a rather complex setup, with the low splitting into two branches of instability, one heading eastward across the Mid-Atlantic, and one moving into the Eastern Great Lakes and become a rather potent storm system Wednesday. Tuesday should be a rainy April day, with constant grey skies, light to moderate rain, and highs in the mid and upper 40s. Rainfall will likely be 0.25-0.50″. Tuesday night will see strong southeast winds and light to moderate rain as the western low pressure core of the storm complex strengthens to our northwest. With lows in the upper 30s, it should stay all-rain Tuesday night.
Wednesday will be something of a sloppy mess meteorologically. The stronger low will be largely stalled over Michigan and Lake Erie, spinning in place, as a secondary low spins up over the New Jersey coast. That reduces the overall strength of the southeast winds because Tompkins County will be between the two counterclockwise-circulating lows. With ample cold air wrapped around the Great Lakes low, temperatures will be below normal, in the mid 40s for highs with a constant light to moderate rain. Wednesday night will be a mix of rain and snow, though amounts of snow are uncertain. Lows will be in the mid 30s in Ithaca, and right around the freezing mark on the surrounding hilltops.
Thursday is arguably even more unpleasant than the prior two days. The Great Lakes low will be dragged westward by its coastal peer, and park over Cape Cod for much of Thursday. Stiff northwest winds and day-long valley rain/hilltop snow are likely. Highs will be in the low 40s. Thursday night will see snow showers across the area as the storm complex moves eastward and cool air is pulled across the region. It will be mostly cloudy and breezy, with lows in the low 30s.
Friday sees the low weaken, but a few lingering rain and snow showers will be possible. It will be mostly cloudy with breezy northwest winds and lows in the mid 40s. Friday night will see partly cloudy and drier conditions as the winds slacken. Lows will be around 30.
Looking into next weekend and the eclipse next Monday, things look unusually good for Upstate New York in early spring. High pressure will work in from the northwest and take the reins for at least a few days. Temperatures will increasing warm as the clockwise flow of the high changes from northerly flow over the area, to lighter winds as its core passes overhead, to southerly winds as the high moves southeast of Tompkins County. Temperatures will rise from the upper 40s for highs Saturday, to mid 50s Sunday and around 60 Monday, with partly to mostly sunny skies. Some partial cloud cover seems possible west of Ithaca Monday, but honestly, and noting that it’s rather far out, things are looking good for eclipse viewers.
Extended Outlook
Looking towards the middle of the month, the large-scale pattern favors a pronounced jet stream ridge over the eastern half of the continental United States, and a substantial trough in the western half. Given the often changeable nature of early spring weather as more heat energy becomes available in the northern hemisphere but cold temps remain in the polar latitudes, this is likely to produce a very wet pattern over the Great Plains with Gulf of Mexico moisture flowing like a faucet. Further east, however, with the moisture being channeled elsewhere and storm systems passing to the north, it will be near to a little below normal for precip in Tompkins County, and rather dry in the Northeast – a period of temperatures into the 70s is certainly a possibility.