ITHACA, N.Y. — Keep the fans handy and the cold drinks flowing; another heat wave is on tap for later this week, with temperatures well into the 90s. Temperatures will fall back slightly, but stay above average next weekend. Unfortunately, there will also be little progress in the next week in alleviating the expanding and worsening drought conditions in the Southern Tier.

Your Weekly Weather

Currently, an expansive area of high pressure sits near the island of Bermuda in the Atlantic Ocean. In the rear flank of its clockwise flow, temperatures are warmer and the air is a little more humid than yesterday, but its still a fairly comfortable day with dewpoints around 60 and a high in the mid 80s. The air is fairly stable, so although there’s ample cloud cover due to a shortwave (pulse of instability) passing to the south, this should remain far enough away while the high steers its northeastward that no rain is expected. However, if you’re heading down to Sayre or Scranton, you might see a few showers.

As that shortwave moves away, the cloud cover will decrease heading into the overnight hours. Temperatures will slide back to the lower 60s with a light south wind.

A Canadian low situated well to the north will enhance southerly flow Monday, as Tompkins County finds itself in the warm sector of its counterclockwise circulation. It will be a hot and rather muggy day with highs around 90 and dewpoint in the mid to upper 60s. The cold frontal trough of the low will begin to approach Monday night, but it will be rather weak this far south. There will be some scattered showers and thunderstorms from sunset to sunrise, but overall precipitation amounts will be less than one-tenth of an inch. Skies will be mostly cloudy Monday night with lows in the upper 60s.

Some northwesterly flow will kick in as the cold front passes Tuesday morning. The air to the northwest isn’t really cool though, because a lot of hot air is being advected into the Midwest by a low over the Dakotas. Temperatures will still top out in the mid 80s with a few lingering showers early as clouds decrease post-frontal passage. For what it’s worth, at least the air to the northwest is drier, so humidity will decrease and dewpoints will be in the low 60s by evening. Tuesday night will be quiet with a few passing clouds and lows around 60.

That low over the Dakota’s is going to move ENE, into Northern Ontario Wednesday. As it does, the angle of that hot air being advected is going to move ENE too – directly into the Eastern Great Lakes, Tompkins County included. At least for Wednesday, even as temperatures climb into the low 90s, the humidity should stay fairly low. In fact, other than being rather hot, with a few passing clouds it will not be a bad day. However, Wednesday night, the low’s cold front, still off to the west, will drive in hotter and much muggier air from the Lower Mississippi River Valley. Dewpoints will creep up overnight, keeping the low elevated – partly cloudy with lows around 70.

This is going to make for a very uncomfortable Thursday, and heat advisories are looking likely. For one, the air temperatures will be in the mid 90s. For two, dewpoints will be around 70. The two in tandem will produce a heat index between 100 and 105 in Ithaca city during the afternoon. Please take precautions if you’ll be outdoors Thursday, and stay cool and hydrated. The moist air will also allow for increasing clouds as the day progresses, with showers and thunderstorms bubbling up. Downpours are likely, but the dynamics aren’t likely to be favorable for severe storms. The front presses through Thursday afternoon-evening, but a shortwave pulse riding along it will keep the atmosphere agitated for showers and a few thunderstorms overnight, with mostly cloudy skies and lows in the upper 60s.

Friday shows some improvement. The shortwave will drag so showers and thunderstorms will pop up throughout the day, though this will be scattered and cellular, so rain will be brief. Skies will be partly cloudy and still rather humid with highs in the mid 80s. Friday night will host partly cloudy skies with lows in the mid 60s.

Looking into next weekend, expected a hot and rather humid weekend, though not so extreme as to merit heat advisories. Skies will be partly cloudy and it should remain dry as a Canadian high passes to the north. Highs will be in the upper 80s Saturday and low 90s Sunday, with overnight lows in the mid to upper 60s, and daytime dewpoints in the mid 60s.

Graphics courtesy of the NOAA Climate Prediction Center.

Extended Outlook

Looking into the second week of August, unfortunately the large-scale pattern shows relief from drought conditions is unlikely. A large ridge in the jet stream will persist over the Northern Great Plains, with Pacific Ocean air working into the Desert Southwest as enhanced monsoonal flow. Here in Upstate New York, temperatures are likely to continue to be warmer than normal, with somewhat drier than normal conditions in tandem.

Brian Crandall

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