ITHACA, N.Y. — After the latest heat wave, many folks are looking for a reprieve. Well, your prayers have been answered, comparatively. High pressure to the north and a slow-moving upper-level low to the south and east will provide for seasonably warm and comfortable conditions, though it will be unsettled. As the low moves away next weekend, however, heat and humidity will return.

Your Weekly Weather

It’s a comfortably warm and dry weekend as high pressure over Ontario and Quebec retains control of Tompkins County’s weather, its clockwise flow bringing dry and somewhat cool air into the region. If you’ve been out Friday night or Saturday night, you might have found the need for a jacket, as temperatures dipped into the upper 40s overnight; drier air loses heat energy more quickly, which allows it to cool off more effectively when the sun sets.

Temperatures have made it into the low 80s at the airport and around 80 elsewhere in Tompkins County this afternoon, with partly to mostly cloudy skies, a combination of fair-weather clouds and high clouds blowing off from a developing low pressure storm system over the Ohio River Valley. This storm system is strengthening and will play a major role in this week’s weather. But for now, it’ll stay dry and quiet, and that continues into tonight with partly to mostly cloudy skies and lows in the upper 50s, somewhat milder than what we’ve seen thanks to the cloud cover and the modest but notable rise in dewpoints expected across the Southern Tier tonight.

The storm system strengthens into a closed low and shifts over Kentucky and the Virginias Monday, which will allow it to upwell moister air into the region. It’ll still be fairly comfortable with dewpoints in the upper 50s. However, given that moister air is naturally less stable, the relative proximity of the low and then add in some August daytime heating, and some scattered showers and a few thunderstorms are likely to develop tomorrow afternoon and evening.

The steering flow is weak, so these cells will move slowly from west to east. Some areas will remain dry the whole day, others may be 0.1-0.25″ of rain from a slow-moving shower or storm cell. Skies will become mostly cloudy by late afternoon with highs around 80. The loss of diurnal heating will shut down the showers after sunset, with partly to mostly cloudy skies overnight and lows in the upper 50s.

Tuesday sees the low drift southeastward, while transferring energy over the Appalachians to a developing Mid-Atlantic coastal low. With the high over Quebec, this sets up a rather unusual northeastern wind, which will moderate the temperature and humidity. There will be a few afternoon showers and weak thunderstorms, with partly cloudy skies and highs in the low 80s. These will once again shut down with the setting sun, leaving partly to mostly cloudy skies and lows in the upper 50s Tuesday night.

Looking into Wednesday, with the coastal low only moving very slowly to the northeast, it will be pretty similar to Tuesday. With light northeast winds, expect a few PM showers and storms, but most areas will remain dry. Skies will be partly to mostly cloudy with highs around 80. A few more showers may be possible as the coastal low strengthens Wednesday night, but the bulk of precipitation should remain well to the east of Ithaca. Skies will be partly cloudy with lows in the upper 50s.

Heading into Thursday, winds shift to a more northwesterly direction as the low moves into Atlantic Canada, which will bring in slightly drier air. Skies will be partly cloudy with a few showers and thunderstorms possible late-day, with highs around 80. Thursday night will see mostly cloudy skies with lows in the mid to upper 50s.

High pressure begins to build in from the Midwest, and this will bring about a change to the weather pattern. It will be stable, but temperatures will rise as hot air crests over the high and into the Northeast. The humidity will remain low initially though, with dewpoints staying in the 50s Friday as highs climb into the mid to upper 80s with sunny skies. Friday night will be partly cloudy and tranquil with lows in the low 60s.

Looking into the weekend, dewpoints will continue to climb, especially as the high shifts eastward over the Atlantic Ocean. While a touch on the muggy side, it will remain stable with partly cloudy to mostly sunny skies and highs in the mid to upper 80s, with overnight lows in the lower-mid 60s. Although this week will be largely dry (unfortunate for our drought situation), it does look precipitation is likely for the start of the week of the 21st.

Images courtesy of the NOAA Climate Prediction Center.

Extended Outlook

Looking into late August, the large-scale weather pattern favors two pronounces ridges in the jet stream, with the greatest flow of unseasonably hot air over the Pacific Northwest and over New England. This will displace enough hot continental air that Pacific monsoonal flow and Gulf of Mexico moisture will be brought in to fill the void, and this humid air will result in above-normal precipitation and below-normal conditions for much of the Southern U.S. A lesser amount of that gets wrapped into the downstream jet and advected towards the Northeast. In sum, above-normal temperatures and near to slightly above-normal precipitation are expected for Tompkins County during the period.

Brian Crandall

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