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John Homenuk

Rain, cold and even snow possible this weekend

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There, we used the “S word” in one of our posts for the first time this season. An energetic mid and upper level disturbance will shift from Central Canada through the Northeast United States late this week into the early part of this weekend, helping to develop a coastal storm. In addition to the coastal storm will come a strong cold front, and a cold Canadian airmass which will drop temperatures into the 30’s and 40’s at times after its passage. With models hinting at the development of multiple surface lows off the coast, the potential exists for not only rain and wind — but some snow in the higher elevations and the first flakes for others.

But the setup remains extremely complicated. The source region of the disturbance means forecast models are already working with a somewhat limited dataset. And, as is often the case with storms in our area, the mid level disturbances will be involved in fragile interactions, all of which will have a major impact on exactly how the storm develops. Confidence, as a result of these small nuances and features, remains very low.

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John Homenuk

Forecast: Clearing, cooler behind cold front

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A warm, humid airmass surged into the region late on Wednesday ahead of a cold front. As expected, low level moisture moving north aided in the development of heavy rain overnight as lift for precipitation moved through our area. Rainfall totals were moderately high in many locations, but we were able to avoid widespread flooding due to the relatively progressive nature of the system. As the mid level disturbance moved northeastward, drier air moved through  much of New Jersey and toward New York City this morning bringing an end to the steady rain.

On the periphery of this mid level disturbance is a cold front, which will push through the remainder of the area this morning after some additional rains fall on Long Island and Connecticut. Gone will be the southerly winds, and making a return will be drier, westerly winds this afternoon. Mid level temperatures, meanwhile, won’t exactly fall off the table until later tonight. So high temperatures today will still reach into the 70’s.

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John Homenuk

Heavy rain, thunderstorms likely tonight into Thursday

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An approaching strong cold front, and associated mid and upper level disturbance, will bring heightened chances for rain into the area from tonight into Thursday morning. However, the event will be made more significant by a plume of moisture, surging northward along and ahead of the frontal boundary. Forecast models indicate a strengthening low level jet stream and transport of this moisture. Precipitable water values (the amount of water in the atmosphere) will be high — in the 95th percentile for October.

The moisture will begin surging northward later this afternoon and evening. Forecast models indicate the best lift for precipitation will remain to our west until the latter part of the afternoon. At that point, from west to east, chances for showers and thunderstorms will increase. Initially, downpours will be scattered. But over time tonight, the support for heavy rain will expand and moisture will continue surging northward. Rain will develop from southeast to northwest, with widespread heavy rain likely throughout the area overnight.

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John Homenuk

Here comes the Autumns first big cold front

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Right on cue. We spoke about this potential a few days ago when we noted the medium range forecast models suggesting the presence of high latitude ridging and blocking. These some models now agree that a significant cold front will shift from the Great Lakes and Central United States through the Northeastern United States this weekend; plowing through our area from Saturday Night into Sunday. Showers and some thunderstorms are possible with its passage, right on the periphery of a major mid and upper level trough.

The temperature different won’t really be felt on Saturday despite the fronts passage. Initially warmer air, streaming in with a southerly flow ahead of the front, will keep temperatures in the 60’s and 70’s on Saturday. After some showers and maybe an isolated storm with gusty winds, the difference will become noticeable as winds shift to west-northwesterly and much, much cooler air begins moving in aloft.

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