August 26, 2010: 5-Day Heat Wave Starts Sunday

Yesterday was the last of the cloudy and chilly days for a while, as high temperatures were only in the upper 60s to lower 70s. A coastal low brought heavy rain from Cape Cod through Boston and into Maine, however a small area of heavy rain also affected western Long Island and places further west, with rainfall amounts as much as locally over an inch of rain.

The rain is now over across most of the area, with partly sunny skies expected for today with comfortable temperatures. Enjoy these conditions while they last, as what could be the last heat wave of the summer will start on Sunday, and will not be a short lasting one.

Tomorrow’s Outlook:

Tomorrow will be mainly sunny with a NW wind expected. High temperatures will rise into the upper 70s to lower 80s across the area, with the warmest temperatures in the immediate NYC area (NE NJ, Rockland/Westchester counties, NYC, western Long Island).

Long Lasting Heat Wave Starts Sunday

Saturday will be a nice day with mainly sunny skies, warming temperatures and a north wind. High temperatures will reach the mid 80s for the immediate NYC area, and the lower 80s for the rest of the area. This will be the last of these days for now, however, as temperatures will not be this low again until late next week.

With a high pressure near the area, a warm air mass will spread in from the west, with 850 mb temperatures climbing towards the 18-22c range. With the high pressure in place, sunny skies and dry conditions will persist until Wednesday or Thursday. These factors will allow for a 5-day widespread heat wave from the Mid Atlantic to the Ohio Valley.

Sunday will already warm up into the lower 90s for the immediate NYC area, with more widespread 90s on Monday, when high temperatures should reach the mid 90s for the immediate NYC area and the upper 80s to lower 90s for most of the area. Tuesday may be slightly cooler as the warmest 850 mb temperatures will stay to our west, with Wednesday potentially slightly warmer as these 850 mb temperatures spread into the area, with the GFS model showing mid to upper 90s for the immediate NYC area.

Relief Comes In The Late Week

Thursday will also be hot, however there could be more cloud cover as the next cold front is expected to approach. There is some uncertainty with the timing, however at this time a cold front is likely to reach the area by the late week, which should likely bring rain and cooler temperatures to the area.

We may have to keep an eye on the tropics as Tropical Storm Earl should be more south/west than Danielle, though should the latest models verify, Earl is unlikely to directly affect the area, with Bermuda having the greatest risk of seeing a direct hit from Earl (more details on that are below). Should Earl affect the area, the cold front would have to slow down and Earl would have to be far west enough to reach the East Coast with the cold front still to its west, which at this time only the 12z GFS showed. Stay tuned for more details in case the scenario for the late week changes.

Tropics: Danielle, Earl, And Potential Fiona

Hurricane Danielle:

Hurricane Danielle is currently a category 2 hurricane, with sustained winds at 105 mph and the low pressure at 970 mb. Earlier today, Danielle has developed an eye, which it has not done so previously, and despite being not too organized, Danielle is strengthening, and will likely become a major hurricane within the next day. As I mentioned in the last few days, the scenario where Danielle hits the East Coast were very unlikely, and the models now backed off from this solution, all of them keeping Danielle east of Bermuda.

Tropical Storm Earl:

Tropical Storm Earl is currently at 45 mph, with the low pressure near 1004 mb. Earl is moving west at this time. Earl should slowly intensify at first, as it is surrounded by dry air at this time, but its environment will gradually become more favorable, and by the weekend, Earl will be able to intensify into a hurricane, with a major hurricane also a good possibility should Earl not suddenly weaken like Danielle has done several times when she was expected to continue intensifying.

For Earl’s track, it will be south/west of Danielle, but the question is whether Earl affects the East Coast or not. There will be a cold front approaching from its west, though if Earl recurves further east, it will stay out to sea. If Earl recurves further west, however, and the cold front is still to its west with supportive timing, then Earl may try to move up the East Coast. More details on this will come over the next few days.

Invest 97L:

Invest 97L has just recently formed south of the Cape Verde islands, and the NHC is giving 97L a 20% chance of becoming a tropical cyclone over the next 48 hours. 97L should continue moving west, and while it will take some time, 97L is likely to eventually become Tropical Depression 8, and later on Tropical Storm Fiona.

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