ITHACA, N.Y. — We’re waiting on the data to be finalized, but much of Upstate New York is coming off of one of its hottest Julys on record. August has started off on the same page, with hot and humid conditions. A rather stormy first half of the week will give way to drier and more comfortable conditions as we head into the weekend.

Your Weekly Weather

It’s another hot and rather humid afternoon as we head into the dog days of summer, with temperatures topping out around 90°F and dewpoints in the mid 60s. The heat of the day is somewhat tempered by the breezy conditions, which are the result of an area of low pressure pushing northeastward from Michigan into Ontario and Quebec. This is creating a weak warm frontal boundary pushing through Upstate, and the primary concern at the moment is that there’s a lot of energy in the atmosphere, a convective cap trapping that energy near the surface in some areas, and a lot of wind shear (turning of the winds) with increasing altitude. If that cap erodes with the heat of the day, some potentially explosive thunderstorm development could occur.

For Ithaca and Tompkins County, thankfully the most energetic and shear-driven environment is not overhead, but to the east, where the warm front has yet to push through and break the mid-level convective cap. If you’re traveling to Albany or New York City this evening, be mindful that a Tornado Watch is in effect for much of eastern New York and the Hudson Valley. Most of the showers and storms firing off will not be major, but there’s the potential for one or two to tap into the freed ambient energy and turn severe, with that wind shear allowing for damaging hail or isolated tornadoes. Keep your phones or radios on if you’re driving out east, so that you can receive NOAA emergency warnings should they be needed.

Turning back to Tompkins County, for the rest of your Sunday don’t expect much, with generally partly cloudy skies and temperatures slipping back through the 80s as we head into the evening hours, and those east of Ithaca should be mindful of convective showers and storms. Sunday night will be quiet behind the front, with partly cloudy skies, a little cloudier towards daybreak as a weak cold front pushes through, and a rather humid night with lows in the mid 60s.

The daytime hours of Monday should be fairly quiet, with a weak high pressure area keeping the air fairly stable during the day. It will be partly cloudy and a little less humid, with highs in the low 80s. An isolated pop-up shower or two is possible, but generally most areas will stay dry until around sunset.

This is where it gets more active and meteorologically complicated, thanks to two features. An upper-level low digging in from Canada (separate from today’s low), and Tropical Storm Isaias (EE-sigh-ee-ahs) will be making its way up the Eastern Seaboard. The low provides instability, Isaias provides tropical moisture, with the two in tandem resulting in an extended period of moderate to heavy rain. This will likely be in the form of rain bands, so there will be breaks, but it will be a wet overnight, with around a quarter inch of rain by daybreak. Those traveling through the Catskills or Poconos will want to be careful, as flash flooding will be a concern in those areas due to topographic impacts and being closer to the tropical storm. Lows Monday night will be in mid 60s.

Tuesday will see the rain continue as the two systems continue to interact. It’ll be something of a summer soaker, with mostly cloudy skies with bands of moderate to heavy rain moving across Tompkins County. The further east you go, the more rainfall there will be, and if Isaias tracks westward, we can expect more rain in that case as well. Highs Tuesday will be around 80°F. New rainfall amounts will be around half an inch, with locally higher amounts. As Isaias moves away and the atmosphere loses its moisture tap, the rain bands will move out, with areas west of Ithaca ending around midnight, and towns to the east a little later. A few lingering showers are likely into the early morning hours, with partly cloudy skies and lows in the mid 60s.

Wednesday will be fairly pleasant as high pressure pushes in from the Midwest. It will be comfortably dry and partly cloudy, with highs in the upper 70s – days with below average temperatures have been rare these past several weeks. Wednesday night will be mostly clear as the high moves closer, with lows in the mid 50s, a comfortable night to sleep with the windows open.

Thursday will be a little warmer as the core of the high moves directly overhead and the light northwesterly winds give way to calm air. Expect a comfortable day with a few passing clouds and a high in the low 80s. Thursday night will host mostly clear skies and a low in the upper 50s.

Friday will be a tad warmer still, as the high shifts eastward and Tompkins County finds itself in the rear flank of its clockwise circulation, creating a southerly breeze. The air aloft should remain fairly stable, though. Plan for mostly sunny skies with highs in the mid 80s. Friday night will be partly cloudy with lows in the low 60s.

The weekend is looking hot and dry, as the high pressure areas stalls out in weak steering flow just to our east. We’ll enjoy stable air, limited humidity and sunny skies both Saturday and Sunday, but you’ll want the fans and air conditioning handy as highs go into the upper 80s Saturday and near 90°F Sunday, with lows in the low 60s.

Graphics courtesy of the NOAA Climate Prediction Center.

Extended Outlook

For those hoping for an extended reprieve from the heat, it’s not in the cards just yet. Looking into mid-August, mid-range models are suggesting a continued ridge in the jet stream over the Northeastern U.S. and Great Lakes regions, meaning abnormally warm conditions will continue as we begin to recede from our climatological hottest time of the year. The models suggests some weak troughing in the Western U.S., with dry continental Canadian air intruding into the Mountain West, and Gulf Moisture advected into the eastern half of the lower 48, creating more humid than usual conditions that are favorable to pop-up thunderstorms with heavier downpours – and by extension, wetter than normal conditions.

Brian Crandall

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