ITHACA, N.Y. — As the days are starting to grow shorter, summer has at least one more hurrah in store for Tompkins County, with temperatures flirting with 90 to start out the week. However, a more seasonable, and arguably more comfortable pattern is in store for the second half of the week.

Your Weekly Weather

It’s an unseasonably hot day across Upstate New York as high pressure centered off the New England coast churns up hot, southerly air in its clockwise circulation. This air is fairly humid, though not yet oppressively muggy, with dewpoints in the low and mid 60s across Tompkins County. This is a fairly stable airmass, so apart from some puffy fair-weather cumulus, the impacts are limited, and the threat of showers and storms is non-existent unless you go well to the south of Ithaca and into Pennsylvania. Highs will top out near 90 under these partly cloudy skies. Sunday night will be mild and muggy, with a few passing clouds and lows in the upper 60s.

Monday will be very similar, though a frontal boundary associated with a Canadian low will begin to press against the high from the west. While the air will remain stable during the day with mostly sunny skies, this trough to the west will enhance southerly flow ahead of it, which will create a hot and tropically humid day. With highs in the low 90s and dewpoints in the low 70s, it will feel more like the upper 90s, so use caution if you’ll be outdoors. Clouds will increase after midnight Monday night as the frontal trough approaches, but it will remain dry, with another warm, humid night with lows staying in the low 70s.

Tuesday will be a very active weather day as rain arrives during the late morning, a littler later southeast of Ithaca. Scattered showers and thunderstorms will roll through the area through the afternoon and evening, with a half inch of rain likely for most areas, and locally higher amounts. The ample amount of moisture in the atmosphere will allow for torrential downpours, so flash flooding will be a concern in urban areas and locales with poor drainage. The risk for severe thunderstorms will depend on the amount of sunlight that works in early, and the timing of the front – the later it arrives, the more heat energy present, and the higher the severe storm risk. It will be muggy and mostly cloudy with highs in the mid 80s. The storms taper off by midnight, with decreasing clouds Tuesday night becoming mostly clear. As cooler air filters in with the front’s passage, lows will be in the low 60s.

Wednesday will be quieter and more comfortable as expansive high pressure pushes in from the Great Lakes. Expect a mostly sunny day with a breezy west wind and humidity dropping to comfortable levels by midday. Highs will be around 80. Wednesday night will be pleasant and calm with partly cloudy skies and lows in the mid 50s.

Thursday sees a second storm system attempt to dig in from the north, but the high should retain control. It will enhance northwesterly flow, so it will be a little cooler as winds turn from the west to the northwest. It will be mostly sunny with highs in the mid 70s. Thursday night will be relatively cool, with partly cloudy skies and lows in the low 50s, maybe some upper 40s on the outlying hilltops.

Friday sees the high move directly overhead, which will stanch the northwest flow. Expect sunny skies with highs in the upper 70s. Friday night will be mostly clear with lows in the lower 50s.

On the back side of the high, Labor Day weekend is looking warm and dry, with partly cloudy skies both Saturday and Sunday. Highs will be in the low to mid 80s with lows in the upper 50s.

Graphics property of the NOAA Climate Prediction Center.

Extended Outlook

Looking into the Labor Day holiday weekend and week beyond, the large-scale pattern calls for a wide ridge in the jet stream over the Northern U.S., resulting in broadly warmer and drier than normal conditions. The displacement of warmer air will allow for some Pacific monsoonal flow into West Texas, creating wetter and cooler than normal conditions for the Lone Star State. At this point, it’s looking like a warm and dry first half of September, which will be great for outdoor gathering, but maybe not so great for the incoming fall harvests.

Brian Crandall

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