ITHACA, N.Y. — Astronomical spring began at 11:33 AM this morning and it will certainly feel like early spring in the city of gorges this upcoming week. We’re not expecting anything particularly disruptive, but with the exception of Tuesday, just about every day will have some chance for rain as a large, slow-moving complex of storm systems passes on either side of Tompkins County. Temperatures will be cool, generally ranging from upper 40s to upper 50s for highs, but should stay mild enough overnight that chances for accumulating snow will be very low.

Your Weekly Weather

Before we jump into the forecast, let’s bust a quick perception. March and April are not the wettest months in Tompkins County, nor the cloudiest. The wettest months are June and July. It just doesn’t feel that way in June and July because they receive more sunlight in length of days, and the kind of rainfall that occurs is less stratiform (steady, lighter rain) and more convective (pop-up thunderstorms that downpour for 10-20 minutes, dropping a half inch or so and moving on). January and February are the cloudiest on average, and they also happen to be the driest months of the year.

However, you could be forgiven for thinking otherwise this week. Some rain showers are moving across Upstate this afternoon on the rear flank of a low pressure storm system passing to the north from west to east, and now over the Gulf of St. Lawrence. Northwesterly winds are passing over the Great Lakes and getting a heat energy and moisture reinforcement to produce some light to moderate rains downwind, including the Finger Lakes. The rest of the day will be rather chilly and grey, with overcast skies and highs in the mid 40s. New rainfall amounts will be less than one-tenth of an inch. These showers should wind down around midnight as the low moves further away and winds slacken, with partly cloudy skies by the early hours of Monday morning, and lows in the lower 30s.

Monday will see more pleasant conditions as high pressure builds in from the south. There will be some chances for an isolated rain shower or two Monday evening as part of a weak shortwave skirts around the high, but a lack of moisture in the mid-levels of the atmosphere most areas will stay dry, though cloud cover will increase during the PM hours to near-overcast by sunset. Highs will be in the low 50s. As the shortwave moves away later Monday evening, skies will clear once again, with partly cloudy skies by sunrise Tuesday and a low in the low 30s.

Tuesday will be quiet as high pressure builds in again, though clouds begin to build in from the west during the afternoon and evening as the next storm system begins to approach. It will be partly sunny in the morning with mostly cloudy skies later, and highs topping out in the low 50s. Tuesday night should remain quiet, as the first showers, likely snow showers, don’t arrive until close to sunrise, with no accumulation expected. Mostly cloudy skies will turn overcast midnight with lows in the low 30s.

Wednesday will be a rather raw, grey and unpleasant day, as the storm system slowly moves towards and over the Western Great Lakes. This system is large and lumbering, with slow forward motion towards the northeast. As a result, Wednesday will be a blustery day with winds out of the southeast, light periods of rain (any snow should quickly change over to rain shortly after sunrise), and temperatures in the upper 40s for highs. The bulk of the rain will fall Wednesday evening and night, though showers will be widespread from early afternoon through sunrise Thursday morning. Rainfall amounts will be between one-tenth and one-quarter of an inch. With the rain and thick cloud cover, Wednesday night will see lows in the low 40s.

Thursday sees the low weaken somewhat as it slowly moves northeastward, but oceanic moisture will give a boost to a secondary coastal low that develops in the wake of its circulation. Tompkins County’s position closer to the Great Lakes low should allow for some southerly flow in its counterclockwise circulation, which will allows for highs in the upper 50s, but it will be a mostly cloudy day with occasional rain showers, so do take the umbrella if you’ll be out and about. Thursday night will see a few scattered rain showers and mostly cloudy conditions continue as those two lows continue to control the regional weather, and lows will be around 40°F.

Friday will see the Great Lakes low slowly pass north of Ithaca, over Ontario and into Quebec, while the coastal lows move into Atlantic Canada. As the western system finally passes Ithaca’s longitude, the winds will be westerly, and therefore not as mild. The rain showers will continue, however. Expect mostly cloudy skies with scattered light to moderate rain showers and highs in the low 50s. Friday night will see mostly cloudy skies with a mix of light rain and snow showers (no accumulations expected) as the storm heads east, with lows in the upper 30s.

Looking into next weekend, Saturday will be cool as northwest winds blow in on the backside of the low. Lake-enhanced instability will drive a few rain showers as highs top out in the upper 40s. There are some signs that behind the low, a surge of polar air will briefly build in for Sunday and Monday, and advected in by those northwest winds, highs are likely to be stuck in the mid 30s Sunday with overcast skies.

Graphics courtesy of the NOAA Climate Prediction Center.

Extended Outlook

Looking ahead towards the end of March and start of April, we can expect some moderation in temperatures following the cold snap at the end of next week, but it’s still expected to average out to below-normal temperatures, with precipitation near normal for the period. The Mountain West will experience weak ridging with some warm Mexican continental air flowing northward into the Southern Great Plains, and an upstream trough resulting in cooler-than-normal conditions along much of the West Coast and into the Desert Southwest.

Brian Crandall

Brian Crandall reports on housing and development for the Ithaca Voice. He can be reached at bcrandall@ithacavoice.com.