July 8, 2013: Scattered Storms To Continue

Forecast Highlights:

Another day of hot and humid conditions was observed across the area, but with slightly lower temperatures and humidity as scattered clouds and storms developed in the afternoon and evening; most storms were focused north of the area, although a few isolated storms affected NYC and parts of northern NJ/SE NY. As a cold front approaches the region and temporarily stalls, more scattered storms, possibly strong, are expected for Wednesday through Friday as temperatures and humidity continue to gradually decrease.

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Tonight - Tuesday: Still Warm And Humid, Isolated Storms

A shortwave trough currently moving through the region will exit tonight, with partly sunny skies and highs in the mid to upper 80s inland and upper 80s to low 90s for the rest of the area. Humid conditions are expected again, not as humid as the last few days but with heat index values still in the low to mid 90s. Isolated storms are expected again in the interior parts of the region during the afternoon and evening hours.


Wednesday - Weekend: More Scattered Storms, Temps Cool Down

A cold front is expected to approach the region on Wednesday, stalling near the East Coast for Thursday and Friday. With the front, another round of scattered showers and storms is expected across the region, some of which could be strong or severe especially inland. Another warm and humid day is expected for Wednesday with highs in the mid 80s to near 90 degrees, although temperatures will gradually cool down on Thursday and Friday into the low to mid 80s as the front stalls nearby. Storms are generally expected to be scattered over the area, focusing north/west of NYC. Although the highest risk of severe weather should stay to the north and west, storms over the area will be capable of producing heavy rain and gusty winds.

By Saturday, the trough is expected to mostly retreat back north into the main flow while a small area of lower heights breaks off and drifts into the southern US. Meanwhile, western Atlantic ridging is expected to expand west, connecting with ridging in the western US to form a broad ridge covering most of the US from west to east with 500mb heights near 588-594dm. This broad ridge is likely to block tropical storm Chantal, currently a 50 mph tropical storm approaching the eastern Caribbean, from tracking up the East Coast in the longer range, instead keeping it on a west or NW trajectory into the southeastern US. Should Chantal survive past landfall over Hispaniola without dissipating, it would likely be a tropical storm during that time period.

Even with the ridge in place, some model runs signal the possibility for a weak 500mb vort to linger over the weekend while western Atlantic and western US ridges connect; partly cloudy skies are generally expected with highs in the low to mid 80s, although isolated afternoon/evening storms can't be ruled out especially inland. Starting on either Sunday or Monday into early next week, should ridging connect from coast to coast as currently modeled, temperatures would rise again into the mid 80s to low 90s range with increased humidity, although one possible change to the forecast is that ridging may not connect as currently modeled, with temperatures sticking in the mid 80s range along with a risk of isolated storms. Stay tuned for more information on the longer range outlook.