June 24, 2012: Rain, Storms Return Tomorrow


Forecast Highlights:



– Rain, strong storms return tonight through Monday noon
– Chilly temperatures briefly return for Tuesday
– Brief heat surge likely in the late week/weekend
– TROPICS: Debby defies forecast, now targets Florida


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June 23 and 24 Observations:

Following Friday’s storm activity, Saturday (June 23) had mostly sunny skies across the area as a high pressure moved through the region. A cooler air mass moved in, although temperatures failed to significantly cool down, with high temperatures reaching the lower to mid 80s inland and the mid to upper 80s across most of the immediate NYC area and Long Island. The warmest temperature was 88 degrees in Newark.

With a high pressure still in place across the region on Sunday, along with a similar set up and little variation in the 850mb temperatures, highs were similar to those of Saturday but ending up slightly cooler, reaching the lower to mid 80s across most of the area with upper 80s in parts of the immediate NYC area, especially near NE NJ. Newark had the warmest temperature again with a high of 88 degrees.

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Tonight / Tomorrow Outlook:


As of this evening, rain has already moved into the area earlier than expected, although the rain will remain light for the main part. As the cold front approaches from the west, additional rain and thunderstorms will form late tonight into Monday morning, with the rain expected to be heavy at times with high precipitable water values. Windy conditions are also possible along with the rain. As the cold front moves through in the afternoon and evening, scattered strong thunderstorms are expected, especially over Long Island and southern CT. High temperatures will reach the lower to mid 70s inland and the mid to upper 70s across the rest of the area. An update regarding the rain will be posted on Monday morning.

Tuesday – Next Week: Chilly, Then Warming Up


Behind the trough, an upper level low will move into the region, with a chilly air mass in the region resulting in widespread below average temperatures. Partly cloudy skies are expected on Tuesday with a risk of an isolated afternoon shower and high temperatures only reaching the upper 60s to lower 70s inland and the lower to mid 70s across the rest of the area. With the ULL slowly moving out, temperatures will gradually warm up, reaching the mid to upper 70s inland and in Long Island/S CT and the upper 70s to lower 80s in the immediate NYC area on Wednesday. Mostly sunny skies will return for Thursday with highs in the lower to mid 80s across the area.

A brief yet strong surge of heat will move into the region on Friday and parts of the weekend, with temperatures reaching and/or passing 100 degrees in parts of the southern Mid Atlantic. The area will be in the northern edge of the warm air mass and will have less of an impact, although at least one hot day is possible, which appears to be either Friday or Saturday, when temperatures may have the potential of passing 90 degrees in parts of the area. There is the potential for scattered thunderstorms at some point during the weekend associated with the next cold front, although there is still uncertainty with the timing of the cold front. Stay tuned for tomorrow’s update for more information on next weekend’s outlook.

Tropics: Debby Defies Forecast, Goes Towards Florida




While models sometimes have trouble handling tropical cyclone tracks, the model performance for Debby could not have been much worse than it was; the spread for Debby’s track went all the way from a due west track to a due east track. As of yesterday, some took it west towards Texas, others took it due north into Louisiana, and others had a northeast track taking the storm into Florida and then offshore. Yesterday, the majority of the model guidance was leaning with the west track; the GFS was the only major model to take the storm northeast into Florida, but half of its ensemble members were also supporting the western track. Despite the official outlook for a western track, however, Debby continued to slowly drift to the northeast, with the models adjusting from a west to a north track throughout the day while the GFS remained steady with a Florida landfall. The models are still not in an agreement regarding the track, with some taking it due north into western Florida and others taking it northeast, but at least the latest forecasts are much closer to an agreement than yesterday’s mess. With Debby still drifting NE and the models shifting east, it is apparent that yesterday’s expectation for a west track will end up incorrect, with my new forecast now supporting a Florida landfall within the next 48 hours. Debby will likely remain a moderate to strong tropical storm when it makes landfall in Florida, with a continued slow NE/NNE track likely. With Debby’s slow motion, additional flooding will continue to take place in northern/central parts of Florida.

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