ITHACA, N.Y. — This will be a good week for spring gardening or a hike through the woods, but you’ll want to keep the jacket or sweatshirt on hand, especially overnight. High pressure will provide for generally placid conditions this week, but the dry air will cool off quickly overnight, and cooler air in the middle week may allow for some patchy frost before temperatures warm back up. Dry conditions may also pose some risk for brush fires late in the week as the lack of rain lately and warmer temperatures take their toll on dry grasses and forest floors.

Your Weekly Weather

High pressure over the Western Great Lakes is bringing cooler if stable air into Tompkins County for your Mother’s Day Sunday. Temperatures are a little below normal for mid-May, but low to mid 60s is still fairly comfortable in the meteorological grand scheme of things. The air is also very dry, with dewpoints in the 30s, so if you have any recent plantings or sinus/skin sensitivities, you’ll want to moisturize your surfaces accordingly.

Something else to keep in mind is that because water vapor absorbs and releases heat energy much more slowly than air, it warms up more quickly in the morning, and cools off more efficiently at night – the same principle underlying how deserts can be super-hot during the day and very chilly after sunset. Translating that to the here and now, it means temperatures will cool off steadily after sunset, and approach lows well below normal for mid-May, enough that if you’re in a typically cooler spot of Tompkins County, you’ll want to cover up your new plantings overnight and bring a heavier jacket if you’ll be out late, especially in the middle of the week when highs and lows will be at their coolest.

For the remainder of your Sunday, expect some high level clouds streaming in from a low pressure system over the Lower Midwest. However, that system will stay to the south. Expect quiet conditions as temperatures slip into the mid 50s by sunset with a northwest breeze, becoming calm overnight as skies clear out and lows fall into the mid and upper 30s across Tompkins County.

Monday will be somewhat warmer as the high begins to split into a western lobe and an eastern lobe, with the eastern lobe establishing a core off the Mid-Atlantic coast. This more southerly flow will bring temperatures into the lower 70s with clear to near-clear sunny skies. Monday night will see mostly clear skies, and while temperatures will still drop off quite a bit, the higher “starting point” will mean that lows will make it to mid and upper 40s by sunrise Tuesday.

A low pressure system over Eastern Canada will swing a cold front boundary towards the region Tuesday. Clouds will increase during the day, going from mostly sunny to mostly cloudy by sunset, but it will stay warm with highs in the mid 70s. Tuesday night will see a few light rain showers – and only a few, as the dry air ahead of the front really limits its ability to develop precipitation – but with north winds developing behind the front late Tuesday evening, temperatures will drop into the upper 30s overnight as cloud cover decreases towards sunrise Wednesday.

Wednesday will be downright chilly, if mostly sunny. High pressure over Hudson’s Bay builds in with a stiff north wind advecting polar air into the area. Highs will only be in the mid 50s. Wednesday night will host mostly clear skies and dry air – temperatures will fall to around 32, so to my fellow gardeners, do be wary of elevated frost risks from Wednesday night into Thursday morning.

The high rapidly moves ESE and passes directly overhead by Thursday. Temperatures will be much warmer, with abundant sun and highs in the upper 60s, just a touch below normal. Thursday night will see mostly clear skies with lows in the mid 40s.

Heading into Friday, the high tracks eastward into the Atlantic Ocean, and it looks like a potential storm system is likely to develop and move from the Upper Midwest and eastward into Canada. This will drive a cold front and its associated precipitation across the region. However, this isn’t likely to happen until after sunset. Expect a stiff south breeze with increasing clouds, perhaps a few evening showers ahead of the front, and highs in the mid 70s. Friday night will see occasional light to moderate rain (welcome rain, at this point), with lows around 50.

Looking into next weekend, Saturday will be unsettled as that frontal boundary slows down crossing Upstate, with showers likely and maybe even a few non-severe thunderstorms possible. Highs are expected to be in the upper 60s. Conditions calm and skies clear out Saturday night with lows in the upper 40s, and Sunday is currently looking to be dry and partly cloudy with highs around 70.

Graphics courtesy of the NOAA Climate Prediction Center.

Extended Outlook

Looking towards your Memorial Day Weekend, the large-scale pattern calls for a pronounced jet stream ridge in the Western United States, with a weaker ridge over the Northeastern U.S. This will allow a large amount of warmer air to move poleward, which will draw in more moist air from the Gulf of Mexico into the Deep South – and that moist air will produce ample cloud cover and cooler-than-normal temperatures. The warm northbound air will be dry continental air, and as a result, the longer-range for Tompkins County calls for a drier-than-normal, warmer-than-normal period as we head into the holiday weekend.

Brian Crandall

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