ITHACA, N.Y. — As of Saturday evening at 5:43 PM, astronomical summer officially commenced across the Northern Hemisphere. Here in our little corner of the globe, it’s certainly going to feel very summer-like. An expansive ridge in the jet stream is allowing a persistent flow of hot and humid air from the Deep South into the Southern Tier, and that pattern will continue for the next several days with little in the way of relief.

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In the immediate future, there isn’t a whole lot to jostle our current weather pattern. Broad southwesterly flow associated with a ridge over the Eastern United States continues to pump in warm, humid air from the Gulf Coast. A weak upper-level low moving from the Mid-Atlantic coast and out over the ocean will provide some instability to the atmosphere aloft, but the dynamics are not conducive for severe thunderstorm development. However, with little steering motion, storms that do develop would be slow moving, and the humidity would allow for some intense downpours, posing a small but notable risk for flash flooding in areas affected by these storm cells.

A weak trough will press along the ridge of hot air by late Tuesday, but in the meanwhile, it’s going to be hot, humid and, for those of us without air-conditioning, rather unpleasant.

For the rest of your Sunday, it’ll be a slow roast to go with your weekend BBQ. Temperatures will top out in the upper 80s in most areas, and with dewpoints in the mid 60s, it’ll feel humid but not awful, enough to pump the heat index up a couple degrees but nothing that would merit advisories or warnings. Some isolated thunderstorms are likely to develop this afternoon and into the evening hours, but these will be widely scattered, and most communities will remain dry. Sunday night will be mild and humid, and as the few pop-up storms dissipate, expect partly cloudy skies and lows in the mid to upper 60s. Valley and lakeside areas can expect some fog and that will reduce visibility, so use caution if you’re driving overnight through the usual suspect areas.

Monday will be a very similar, with perhaps slightly stronger southwesterly flow as that trough begins to press in from the northwest. This will add a little more heat and humidity to the air, and the more humid conditions in combination with the closer presence of the trough will likely set off some PM showers and thunderstorms, most prevalent between 1 PM and 7 PM. Outside of those storms, skies will be partly cloudy with highs around 90 °F. Monday night will see the storms die off with the loss of diurnal heating, and another rather muggy, partly cloudy night with lows in the upper 60s.

Tuesday will start off much the same – humid, with temperatures quickly climbing into the upper 80s with partly cloudy skies in the morning. However, with that trough coming in, storms will begin to fire off by noon, and it’s looking like there will be rounds of slow-moving thunderstorms interspersed with periods of intense June sun – it’s going to feel oppressive and steamy with dewpoints into the low 70s, just a gross day to be outdoors. Some of the showers and storms will weaken with the loss of daytime heating, but the front is slow-moving and it will be a sticky night, with rounds of showers and thunderstorms, mostly cloudy skies otherwise, and lows around 70 °F.

The front will have shifted east of Tompkins by Wednesday, but some remnant instability will result in a few more showers and thunderstorms throughout the day, with mostly cloudy skies otherwise. It will be a little cooler and a little less muggy, but still making it into the mid 80s and still rather humid with dewpoints in the low to mid 60s. The marginally drier and cooler air will continue to work in overnight Wednesday, with partly cloudy skies and lows in the upper 50s.

If you’re looking for a big change in the weather pattern, this won’t be it. Thursday will feel a little drier, with dewpoints hovering around 60 °F, the rule of thumb boundary between comfortably dry and rather humid. But temperature-wise, it’s practically the same, with highs topping out in the mid 80s under mostly clear skies. Thursday night will be partly cloudy with lows in the upper 50s.

Friday will be much of the same, with partly cloudy skies and highs in the mid 80s. A low pressure system well to our north in Canada will add a little more instability into our local column of atmosphere, and that could result in a few isolated showers and thunderstorms late in the day. But nothing major. Friday night will see partly cloudy skies as the few showers wither away, and lows in the upper 50s.

Looking ahead into next weekend, it’s looking like somewhat more humid air will return for Saturday and Sunday, and with temperatures in the mid to upper 80s, it’ll be another hot and humid weekend. Plan for partly cloudy conditions with a few potential pop-up showers and thunderstorms late. If you have access to a pool, now’s the time to make good use of it.

Graphic courtesy of the NOAA Climate Prediction Center.

Extended Outlook

Looking ahead into the start of July, the warmer-than-normal stretch is expected to continue as a ridge of hot air persists over the Great Lakes and Northeast, with a persistent jet stream trough bringing cooler than usual conditions to the West Coast. Precipitation will run near to perhaps a little below normal for the period. The United States Drought Monitor at the University of Nebraska-Lincoln is noticing abnormally dry conditions throughout much of the Northeast, and drought conditions are likely to develop in New England.

Brian Crandall

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