Aug 8, 2011: More Storms Tomorrow Night

Today brought partly cloudy skies across most of the area with highs reaching the mid to upper 80s inland, lower 90s in the immediate NYC area, and the upper 80s to lower 90s across most of Long Island/S CT as well. While storms were not as widespread as yesterday, some scattered storms were observed in the northern half of the area, especially in SE NY, where a few strong thunderstorms affected places such as Westchester, Rockland and Orange counties. These storms have dissipated since then.

Another low pressure will approach the area tomorrow evening, bringing locally heavy rainfall for tomorrow night across most of the area, but once this low pressure exits, it will pull in a colder air mass, with temperatures reaching their lowest point since June. Dry conditions will continue through Saturday before another low pressure approaches the region on Sunday, bringing another risk of rain.

Tomorrow’s Outlook:

Tomorrow will bring increasing clouds to the area, with scattered thunderstorms starting to affect places west of NYC by the late afternoon. High temperatures will be colder than those of today, reaching the lower 80s inland, mid 80s in the immediate NYC area, and with a SE wind expected, temperatures in Long Island/S CT will reach the lower 80s.

For tomorrow night, while the main low pressure will be in Canada, a wave of low pressure is expected to move near, if not over the area, with widespread storms starting to affect the area after 10 PM-12 AM. The wave of low pressure is likely to enhance the rain amounts in the northern Mid Atlantic/southern Northeast, but exactly where this happens is still uncertain. At this time, the model consensus is for the heaviest rain to stay north of the area, and for tonight’s update, I am expecting the heavier rainfall amounts to end up over the northern half of the area, where a general 1/2 to 1 inch is expected with amounts locally up to 1.5-2 inches, with lighter amounts in the southern half of the area. Stay tuned for more information on tomorrow night’s storm with an update tomorrow afternoon.

Wednesday – Saturday: Drying Up, Colder

The low pressure will be east of the area, over New England, by Wednesday afternoon, which will help bring drier conditions into the area. While rain is expected to continue through the morning hours, dry conditions are expected after 10 AM-12 PM across most of the area. Cloud cover will clear by the late afternoon with increasing temperatures, reaching the mid to upper 80s from NYC and further west and the mid to upper 80s in Long Island/S CT with a west wind expected. A few places in the immediate NYC area may reach the 90 degree mark if there is enough sunshine.

Behind the cold front, a significantly colder air mass will move into the region, with 850 mb temperatures dropping into the 8-11 degree celsius range, the first time this has happened since June. This will bring colder temperatures as well, reaching the upper 70s across most of the area, with upper 70s to lower 80s in the immediate NYC area. Low temperatures on Thursday night will be colder as well, as mostly clear skies and light winds under a high pressure will bring low temperatures into the mid to upper 50s in NW NJ, SE NY and southern Connecticut, upper 50s to lower 60s in Long Island/NE NJ, and mid 60s in NYC. Temperatures will gradually warm up on Friday and Saturday, reaching the mid 80s in the immediate NYC area on Saturday.

Sunday: Another Storm Arrives

Another low pressure is expected to move towards the region on Sunday. The exact track of this is still uncertain, ranging from near the area on the ECMWF/DGEX to Canada on the GGEM and some GFS runs, but this storm is expected to bring another round of rain and thunderstorms into the area on Sunday. Severe weather risk, if any, is still uncertain at this time. More information will be posted on Sunday’s storm over the next few days as details become clearer.

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