ITHACA, N.Y. — Let’s not sugarcoat it. Weather-wise, this weekend is awful.

From a forecasting standpoint, it was like watching an incoming car crash. With each successive run, the developing coastal storm grew larger thanks to help from an upper-level low to the west, more potent and hugged the coast more tightly. This allowed for two unfortunate things – one, as the storm strengthened, its pressure deepened, which in tandem with its size growth allowed for it to tap into much colder polar air well to the north. Two, hugging the coast allowed it to tap into oceanic moisture to feed its precipitation shield, and shunt all that in a counterclockwise motion around its core – drenching must of New England, the Northeast, and Mid-Atlantic during an economically vital holiday weekend.

In winter, this would be similar to a strong Nor’Easter – undoubtedly there would be feet of snow followed by much below normal temperatures. But in late May, that amount of frigid air isn’t in place, and in fact to keep it this far below normal (20-25°F for daytime highs) takes an enormous atmospheric effort. This is why it’ll warm up relatively fast as we head into the week.

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In the first good weather news in a few days, the coastal low is lifting away to the northeast, and so the last of its rain showers will be moving out this afternoon. However, with a light wind from northeast and remaining from the north before settling down by tomorrow morning, it will remain cold and cloudy today. After highs in the mid 50s, temperatures will recede slowly into the low 50s by sunset with cloudy skies overhead, and with the moisture on the ground (humidity) and those clouds persisting overnight, it won’t cool off much, with lows in the mid 40s.

For those with the three-day weekend, Monday will be a substantial improvement. High pressure will be working its way southwestward into the Ohio River Valley, which would stabilize the atmosphere and clear out much of the cloud cover. Being late May, this will allow the high sun angle to really warm things back up, though with the clockwise flow around the high, the winds will turn to the northwest and it will be on cool side of normal – but a lot warmer than now. Highs will be near 70°F for Memorial Day with partly cloudy skies. Monday night will see some cloud cover spill back in on the back of the coastal low, but it will remain dry, with mostly cloudy skies and lows in the upper 40s.

Tuesday will see the high shift eastward into the Atlantic, and the rear flank of its clockwise circulation will generate southerly flow. This will bring somewhat warmer and more moist air into the region, though still comfortable with dewpoints in the 50s. The high will top out in the mid 70s with partly cloudy skies. Tuesday night will continue the high’s control, with partly cloudy skies and highs in the low 50s.

As the high moves a little further away to the east on Wednesday, the reduced stability combined with more moist flow will create a more unsettled day, with some pop-up showers and thunderstorms possible in the late afternoon through the evening. This is not a washout, and not all that muggy either. It will be partly cloudy early and mostly cloudy in the PM with highs in the upper 70s. The arrival of a frontal boundary Wednesday night will usher in some periods of light to moderate rain overnight, so expect occasional rain and cloudy skies through Thursday morning, with lows around 60°F.

Thursday will be a mostly grey day, with occasional light to moderate rain. The models aren’t confident in the timing, with the European ECMWF preferring an early period of steadier rain in the morning, and the American GFS in the afternoon, but needless to say, expect a wet if warm day, with highs in the mid 70s. These showers will continue into Thursday night and Friday morning, if not quite as prevalent after midnight, with mostly cloudy skies and lows in the low 60s.

Friday will be more typically summer-like as a warm and humid air mass builds in from the southwest. It will be rather humid and warm, with partly cloudy skies and a few scattered showers and thunderstorms later in the day, thanks to diurnal heating and the less stable atmosphere high humidity creates (air parcels are more buoyant when there’s more moisture in the air). Highs will be around 80°F. The storms will wind down with the loss of daytime heating, leaving partly cloudy skies Friday night with lows in the low 60s.

The weekend is looking warmer and on the humid side. Saturday will be in the mid 80s, and Sunday will come close to 90°F, with dewpoints in the mid 60s and generally dry conditions as an intense ridge of hot, stable air builds across the Northeast.

Graphics courtesy of the NOAA Climate Prediction Center.

Extended Outlook

Looking into the second week of June, that hot, hot ridge will create an unseasonably hot spell for much of the Northern United States, as well as drier than normal conditions. Something has to fill the void for that hot air, and moisture off the Gulf of Mexico will join air over the Deep South to create wetter than normal conditions along much of the Gulf Coast. Only Alaska, the Pacific Northwest and Texas are likely yo see cooler-than-normal conditions during the period.

Brian Crandall

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