July 16, 2012: Peak of Heat Tuesday, Weds

Forecast Highlights:

– Heat to peak tomorrow, mid-upper 90s NYC and north/west
– Slower front than first thought; scattered storms from Weds through Friday
– Seasonable, dry weekend expected


Today’s Observations:

Following yesterday’s storms, mainly dry conditions were observed across the area with the exception of a few very isolated storms especially further inland. Temperatures were warmer as a slightly warmer air mass moved in, with highs reaching the lower to mid 90s across most of the area with upper 80s in some parts of southern CT and Long Island.

The 3rd heat wave for the region, 4th one for most of the area when including the single day that interrupted the late June-early July heat, will extend through Tuesday and Wednesday, with highs reaching the mid to upper 90s from NYC and further north/west on Tuesday and Wednesday with heat index values reaching and possibly exceeding 100 degrees. A slow moving cold front will then enter the region, with scattered strong/severe storms on Wednesday evening with additional scattered storms on Thursday and possibly Friday. Drier conditions will return for the weekend, but for the first time since mid June, there likely won’t be a heat wave following the period of cooler temperatures.

Tuesday – Wednesday: Hot, Humid

The peak of the heat wave will take place on Tuesday and Wednesday with mostly sunny skies, WSW winds, and 850mb temperatures near 20-21C. Temperatures will reach the mid to upper 90s from NYC and further north/west on both days, with lower to mid 90s across most of Long Island/S CT, a bit warmer closer to NYC and cooler further east. By Wednesday in the late afternoon and evening hours, a cold front will approach with scattered thunderstorms, some of them strong/severe and capable of producing heavy rain. More information on Wednesday’s severe weather potential will be posted with Tuesday’s update.

Late Week – Weekend: Stormy, Then Drier

Originally, the cold front was expected to drop south of the area, with a seasonable and dry ending to the week. With the passage of the front trending slower, however, the front is expected to slow down over the area, keeping mostly cloudy skies and occasional showers in the forecast through Thursday and possibly Friday. High temperatures on Thursday are still expected to be in the mid to upper 80s for most of the area, ending up cooler in some places, with Friday’s highs more uncertain due to model differences with the rain but likely to end up somewhere around the lower to mid 80s range.

By next weekend, with the high pressure moving south of the area, drier conditions are expected with seasonable temperatures, although at this time there does not appear to be a heat wave building in behind the stretch of cooler temperatures as a weak trough moves towards the region with the core of the heat staying west. While this pattern is not expected to be a persistently cooler than average one, it is expected to result in a cooler ending to July compared to the first 20 days of the month, with perhaps more rain chances. Stay tuned for more information on the longer range outlook.

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