 |
| The areas of the nation covered by heat advisories and warnings (most of the orange and purple areas) has expanded since yesterday and now includes Vermont and New York. |
Today's weather will be nothing special in terms of summer toastiness, with highs in the 80s.
The real show begins Saturday. And there's a new twist to the beginning of this heat wave. I'll get into that in a bit.
All of Vermont and New York are now under heat advisories. The one in Vermont seems to go on forever - from noon Saturday to 10 p.m. Monday. And even that might get extended beyond Monday. We're only a small fraction of a huge expanse of the nation now under heat advisories and warnings.
Here comes the twist: After the first of a long string of 90 degree days Saturday, northern parts of New York and Vermont might be affected by something called an Mesoscale Convective System, or MCS.
An MCS is a large cluster of thunderstorms that often form in the late afternoon and evening and continue well into the night. They are very common in the Plains and Midwest, but under certain circumstances can hit us, too.
Within an MCS, there are often severe thunderstorms embedded within it, with strong straight line winds usually the biggest threat.
The system that might affect us later Saturday will form in Ontario and Quebec, then possibly skirt northern New York and Vermont. There's a chance it might weaken by the time it gets here, but that's uncertain.
I do know that when you're on the northern edge of a strong heat ridge, like we will be on Saturday, there's the risk that thunderstorms can develop explosively if there's a trigger. This could be the trigger, but as always, that's uncertain.
For the record, NOAA's Storm Prediction Center has us in a slight risk zone for severe thunderstorms Saturday because of this potential MCS.
After that, the heat grinds on. There have been subtle changes in the hot spell forecast. It was thought that Sunday would be the hottest day of the streak, but it's beginning to look like Monday might be the most extreme. (Both days will be almost equally hot, and terrible.)
This slight change in the forecast is because the weak cold front that was due to be approaching us later Monday looks even wimpier than first thought. And slower. So it won't produce any clouds of note, or thunderstorms to put a lid on the heat. It'll just be blazing sunshine on Monday, just as it will on Sunday.
There's been a lot of speculation here in this blog thingy and in many other places whether Burlington will get to 100 degrees for only the fifth time on record. If that happens, it's now a bit more likely that this would happen on Monday instead of Sunday.
The Very Wimpy Cold Front will wash out before it really gets here, so the heat will go on all of next week. Which means this could easily be one of Vermont's worst heat waves on record.
This could change, but right now, the National Weather Service is calling for at least six consecutive days with temperatures in the 90s at Burlington. Only four heat waves since the 1880s have lasted that long. This heat wave will arguably rival the two gold standards for extreme heat in Vermont, which are huge hot spells in July, 1911 and August, 1944.
There's always the chance a subtle disturbance in the atmosphere could trigger a few isolated strong to severe thunderstorms during any part of this heat wave, but right now, that doesn't look like it's in the cards. However, forecasters usually don't see these coming until a day or two before they happen.
By the way, we're not the only ones that will suffer through this heat wave. Most of the nation east of the Rockies is sharing in this as well.
Back here in Vermont, I don't see any real cold fronts ending the heat wave until around Saturday, July 7. If you don't like heat, here's a glimmer of good news. At least one computer model has us in a fairly long stretch of generally cooler than normal weather through the middle of July.
Time will tell if that comes true. I would like it to.
No comments:
Post a Comment