Thursday Update: Heat Wave Forecast Looks Even Worse

The worrying forecasts for a heat wave next week keep getting worse.

Heat danger map for next Wednesday from the 
National Weather Service. Orange areas are
moderately at risk for causing heat illnesses
in people. .Red and especially purple areas
are much more dangerous. You can see
Vermont is in the red zone.  If you look
closely there's a couple dots of purple
around here, too. 

The expected heat is slowly coming into better focus as we get closer to the event. So far, the forecasts have been consistent. Though things could still change, the forecast for the expected heat is becoming more solid. At least for the first couple of days of the event. 

However, while it might cool slightly after Wednesday, that cooling would not be all that much, and might be temporary. 

This still looks like a nasty heat wave for the most of the eastern two thirds of the U.S., including us here in Vermont. 

THE DETAILS

Before we get to the heat, we have one more very welcome blast of cool air to get through. Today will be noticeably warmer than the past several. Southerly winds ahead of a cold front are bringing in that balmy, slightly more humid air. 

Most of us should get at least into the low 80s, and dew points - a rough measure of how humid it feels - should get a little over 60 degrees this afternoon. That will feel just slightly stuffy to some of us, but it won't be oppressive yuck.

The cold front will come through tonight and probably mostly during the first half of tomorrow. The timing is such that any severe thunderstorms will be well to our west today, and a little to our south an east in central and southern New England tomorrow.

That blast of refreshing air for Friday night into Sunday morning looks like it means business. Highs Saturday will only get into the 60s to near 70 despite sunny skies. Pretty much all of us will be in the 40s Saturday night, with the cold hollow like Saranac Lake, New York or Island Pond, Vermont touching the upper 30s. 

That actually isn't weird for Vermont in June, though. 

Heat Builds

The heat wave will be weird - and dangerous.

Sunday still looks nice and comfortable. Sure, the temperature will rise a bit, 70s to around 80. Humidity will still be fine. 

That very dark red over Vermont and the eastern
Great Lakes reflects the highest possible 
confidence that it will be hot next week. 

But the wind by then will start gently blowing from the southwest and that will be the start of this mess.

Monday will be something of a transition day. The early morning will start fairly comfortable, but by afternoon - ugh. Well into the 80s and rising humidity. 

When I started typing "Tuesday" spell check changed it to "queasy" and that's how I feel about the forecast for Tuesday and Wednesday. Most of us will be over 90 degrees. Mid-90s and high humidity are on tap for banana belt towns, like the Champlain Valley. 

Surprisingly, those mid-90s temperatures expected in Burlington Tuesday and Wednesday are unlikely to be record highs. They would be on most other days in June. 

However, Tuesday and Wednesday fall on the anniversaries of the two hottest June days on record. (97 degrees June 18, 1994 and 100 degrees June 19, 1995).

The National Weather Service has a new one to four scale heat intensity forecast, kind of like the risk scales you see for severe thunderstorms and floods. The heat wave scale has us in Vermont at a level three, borderline level four  by Wednesday, which would be rare for northern New England. 

Level Four is described this way:  "This level of rare and/or long-duration extreme heat with little or no overnight relief affects anyone without effective cooling and/or adequate hydration. Impacts likely in most health systems, heat-sensitive industries and infrastructure."

In other words, this will be a dangerous heat wave for Vermont and for tens of millions of people from Missouri to Montreal. That includes us. Remember, heat kills more Americans than any other weather event, including tornadoes, hurricanes and floods. Take this one seriously when it arrives.  

The heat dome that will be affect us and millions of others in the Northeast and Midwest will be quite strong Tuesday and Wednesday.

That minimizes, but doesn't eliminate the chances of severe thunderstorms to mix into this mess. When it's that hot and humid, the atmosphere is a powder keg. Northern New England will be fairly close to the edge of the heat dome, so any little disturbance can come along and trigger widely scattered, but intense storms. We'll have to keep an eye on that during the heat wave'

Beyond Wednesday

Weather forecasts are always more sketchy beyond a week from now, so we do have to take the with a grain of salt.

Broad brush, though, the weather pattern strongly favors continued heat and humidity through the end of the month. It does seem like a good bet that a weak cold front or two might come through sometime between Thursday and Sunday, which would temper the heat and humidity.

That would make things much  less dangerous. But it's still unclear just how cool it will get.  It certainly won't be refreshing like the air we're expecting this Saturday.  Judging from the forecast for the next couple weeks, the predictions we heard during the spring that we would have a  very hot summer might just be coming true.