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Update: Slight Risk of severe storms from SPC

The Storm Prediction Center has placed parts of Northern New Jersey, Southeast New York ,Connecticut, and the New York City Metro Area in a “Slight Risk” for severe thunderstorms Wednesday afternoon and evening. The “Slight Risk” category is triggered by probabilities of severe weather within 25 miles of a point — and in this case the SPC indicates a 15%-30% chance of severe storms within 25 miles of any point in that area.

Scattered thunderstorms are expected to develop over Pennsylvania and New York later this afternoon before moving into Western New England and Southeast New York. The storms may then eventually drop south and east towards Northern NJ and New York City. However, confidence is higher in the potential for storms to the north of our area. Here, better shear and instability parameters are juxtaposed to support organized severe thunderstorm potential. One forecast model, run for the Storm Prediction Center, suggests the storms may move farther south — into Northern NJ and NYC ( see below ).

SPC-WRF model, forecasting strong thunderstorms impacting the NYC Area Wednesday evening.

SPC-WRF model, forecasting strong thunderstorms impacting the NYC Area Wednesday evening.

After a warm front passed the area this morning, southwesterly winds ushered in a much warmer and more humid airmass. So, the potential exists for the strong storms to move into the NYC Area later this evening despite the fact that the better support for severe weather remains to the north.

Stay tuned for updates on potential watches and warnings from the National Weather Service through the afternoon (this post will be updated).

Damp Tuesday, but big warmup en route

Warm fronts can be pretty deceiving. Depending on the positioning of the front at the surface, and the amount of warm air that looms behind the front, conditions can seem fairly raw and damp near and ahead it. Much of the same is true in our area today, as east winds ahead of a surface warm front to our south along with a weak low pressure system riding along the front itself will provide cooler conditions and periods of rain.

Waiting behind the front, which will pass the area early Wednesday, is a surge of warm air. Temperatures at the 850mb level will rise from around 8-9 C Tuesday morning, to 15-16 C by Wednesday — and even warmer on Thursday. At the surface, highs in the 60’s on Tuesday with clouds will rapidly rise into the upper 80’s and lower 90’s later this week. In addition, a westerly wind component should help the warmth get all the way to the coast — and limit the inland extent of the seabreeze.

Showers and storms, however, will linger through Wednesday before the heat arrives. In fact, the Storm Prediction Center suggests a small chance (5-15%) of a severe thunderstorm in the area as the warm front passes on Wednesday. Stay tuned for further updates. Their probabilistic outlook, shown below, suggests the best chance for severe thunderstorms will be farther north — where the warm front will be Wednesday afternoon. A slight chance of storms capable of producing gusty winds exists as far south as New Jersey.

Storm Prediction Center Day 2 Outlook, valid for May 29th, 2013. The probability of any severe weather within 25 miles of a point is shown. A 15% probability (yellow) triggers a "Slight Risk" of severe weather.

Storm Prediction Center Day 2 Outlook, valid for May 29th, 2013. The probability of any severe weather within 25 miles of a point is shown. A 15% probability (yellow) triggers a “Slight Risk” of severe weather.

Stay tuned for further updates on not only the potential for storms, but the impending warmup and warm frontal passage on Wednesday. You can follow our social media accounts on Facebook and Twitter for more frequent updates and posts throughout each day.

Clouds, drizzle will give way to a warm Thursday

 

Spring 2013 certainly has not been “warm” by definition, with plenty of transitions and colder than normal airmasses moving through the Northern tier of the United States. There have, however, been a fair share of warmer than normal days — with several featuring high temperatures well into the 70’s across parts of New Jersey and New York City. Thursday will be another one of those days.

With a warm front moving through the area, some clouds and spotty showers are expected through the morning hours. With time, these clouds will burn off and give way to partly cloudy skies. Temperatures will rise into the mid to upper 70’s throughout much of the area, with parts of New Jersey potentially approaching the lower 80’s. A frontal zone moves through later Thursday Night with a period of clouds (but little precipitation expected), and Friday will end up several degrees cooler — but still pleasant with highs in the lower 70’s.

The main noticeable change will be the wind direction, as west-southwesterly winds on Thursday will give way to northerly winds behind the front on Friday. Looking ahead, some more unsettled weather with showers and storms is expected as we move into the weekend. Details on the weekend forecast are forthcoming in a blog post later this evening!

PM Update: Warm, stormy end to the work week

Unsettled weather has gripped the area over the past day or so — after a prolonged period of pleasant and dry weather. Over 2 inches of rain fell in New York City on Wednesday as an upper level low moved near the area and moisture streamed into the area. Thursday featured some rain as well, but it was more spotty and scattered as opposed to the synoptic type heavy rain which fell along the warm front Wednesday. The forecast will remain unsettled through the end of the work week and into the weekend, but a warming trend will also be noticeable. This will be especially true on Friday, ahead of a cold front, when temperatures could warm into the upper 70’s to lower 80’s throughout much of New Jersey towards New York City.

The catch, however, will be the disturbance approaching aloft — and the cold front approaching at the surface. Showers and thunderstorms will become scattered by Friday afternoon over Pennsylvania and Western New Jersey and could move into the area overnight Friday into Saturday. Although Saturday will likely be warm as well, thunderstorms and periods of rain appear likely with the frontal boundary near the area. The Storm Prediction Center has placed the area in a 5% risk of severe thunderstorms (a tier below the 15% that would trigger a “Slight Risk). Clearing is expected by Sunday with colder temperatures moving into the area behind the front.

Stay tuned over the next day or so for updates on the approaching disturbance and cold front, as well as any potential thunderstorms and associated watches and warnings.

For a day-by-day breakdown of the forecast, check out our Forecast Brief. If you’re looking to get more details and technical reasoning, check out our Technical Forecast Discussion. Have a great night!