ITHACA, N.Y. — Get your air conditioning installed, your outdoor work finished, and your cold beverages stocked up. A heat dome of hot, humid air will envelop much of the Eastern Great Lakes and Northeast in the week ahead, with widespread, unusually severe heat expected for much of the region in the coming days. A Heat Advisory is in effect from 12 PM Tuesday to 8 PM Thursday.
Your Weekly Weather
High pressure currently over New England will move southeastward into the Western Atlantic over the next 24 hours. In that new position, the large, strong clockwise-circulating high will bring in ample amounts of hot, humid air from the southwest, including a powerful, thick layer of hot air normally limited to the Desert Southwest and Texas. This phenomenon, called a heat dome, intensifies a heat wave because it creates high pressure aloft – think of it as an upper-level high, vs. the upper-level lows that occasionally impact our region.
What that heat dome does is serve as a lid on hot air created at the surface. It produces a stable atmosphere at high altitudes that heated ground-level air struggles to rise into and penetrate. Instead, the hot air recirculates and continues to heat up near the surface instead. This also means that pop-up showers and thunderstorms will struggle to develop, because while the heat energy is present, it’s not strong enough to work through an unusually powerful layer of hot, stable air aloft.
Please take the heat and humidity seriously. NWS Binghamton is already having to push back against members of the public trying to minimize the risk. Yes, it’s June. But this is going to be the kind of severe heat wave that we typically only see once a decade, and it’s all the more unusual given we have yet to reach the first day of astronomical summer. Daily high temperatures will fall, and potentially monthly high temperature records will fall in some areas. Take steps to prepare, know how to stay cool, and be aware of the symptoms of heat exhaustion and heat stroke by reading through the handy guide linked here.
For the remainder of your Sunday, it’s a pleasant day before the heat cranks up. Mostly sunny to partly cloudy skies will close out the day, with temperatures sliding from highs in the low 80s with comfortable humidity, to around 70 by sunset. Tonight will host partly cloudy skies and milder overnight lows than what we saw earlier this weekend, with temps only receding to the mid 60s.
Monday will be a much warmer and muggier day as southwest flow starts advecting the heat dome into the region. Skies will be mostly clear, but an isolated thunderstorm or two may develop in the broader Finger Lakes and Southern Tier, as the heat dome won’t fully be in place yet. Highs will be in the low 90s with dewpoints in the upper 60s, making it feel like the upper 90s. Monday night will see mostly clear skies and mild overnight lows around 70.
Tuesday will be a mostly sunny with oppressive humidity and little if any wind. Highs will be in the upper 90s, and with dewpoints in the mid 70s, it will feel like 105-110 F during the late afternoon and early evening hours (2-6 PM). A stray thunderstorm well northwest of Ithaca will be possible. Tuesday night will be humid and warm, with gradually increasing clouds towards sunrise, and lows in the lower 70s.
Wednesday Juneteenth will be another very hot and humid, with partly cloudy skies and a light south wind. Highs will be in the mid to upper 90s with dewpoints again in the mid 70s, so it will feel like the mid 100s. Wednesday night will be partly cloudy, humid and warm, with lows in the low 70s.
Thursday will be another hot and humid day for the first day of astronomical summer, as the high holds position over the Western Atlantic and the southwest flow continues to replenish the heat dome. It could get weak enough on the fringes, however, for some thunderstorms to fire up, primarily north and west of Ithaca. Otherwise, it will be partly cloudy, hazy, and hot for the longest solar day of the year, with highs in the mid to upper 90s, dewpoints in the 70s, and a heat index in the low to mid 100s. Thursday night will see more clouds build into the region, with warm and humid overnight lows in the low 70s.
The ridge of high pressure begins to flatten out Friday, which will allow for a slightly cloudier, more unstable, and cooler environment. A few scattered showers and thunderstorms will be possible later in the day, with partly to mostly cloudy skies and highs in the low 90s, that with the humidity will feel like upper 90s to around 100 degrees. Friday night will see pop-up storms die off with the loss of daytime heating, leaving partly cloudy skies and humid overnight lows in the upper 60s.
Looking into next weekend, some relief is on the horizon as the Atlantic high sinks southward and a storm system approaches from the Western Great Lakes. It will still be humid, but it will be cloudier with scattered thunderstorms later Saturday, and throughout the day Sunday. Highs will be in the upper 80s Saturday, and low 80s Sunday, with overnight lows in the mid to upper 60s.
Extended Outlook
Peering into the end of June, the large-scale forecast ensemble indicates a broad ridge of unseasonably hot air over much of the lower 48, with an upstream trough impacting the Pacific Northwest and Alaska. Temperatures are expected to be above normal for the end of June. Meanwhile, on the precipitation side, apart from Gulf moisture in the Mississippi River Valley, there aren’t any strong moisture signals, so rainfall is likely to be near to a little above normal for Tompkins County during the late June period.
