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  • Writer's pictureMy Personal Weatherman™

Blizzard Warning probable for NYC & western Long Island; NWS not ruling out 2 feet!

Here is latest snow map from the National Weather Service through 1 AM Wednesday. As for Long Island, there is still uncertainty in snowfall amounts, but a Blizzard Warning will likely be issued this afternoon for Nassau and the western half of Suffolk. The following is from the National Weather Service covering Long Island and the Tri-State area: "The forecast continues to trend snowier for much of the forecast area. The modeling still leaves a good amount of uncertainty with regard to mixing for the eastern half to third of the area. The NAM and GFS,including the 6Z NAM, are essentially the cold models. The GFS warmed the boundary layer significantly during the afternoon across LI, which seemed unrealistic given the wind direction except for close to the immediate south shore and Twin Forks. It stayed cold aloft. The 00Z NAM kept the boundary layer cold, but surged enough warm air aloft to produce some mixing with sleet for much of LI by afternoon. The 6Z run backed off on this. Both models warm things aloft briefly after 7 PM Tue, but by then most of the damage will have been done. The ECMWF came in with a warm solution, which would result in extensive mixing even potentially to NYC by afternoon. Based on the good agreement between the NAM and GFS, and the good track record of the NAM, the forecast leans on the American models. It is a lean however and not a full buy in at this point. Snowfall amounts have been increased for almost the entire area. Amounts were lowered on the South Fork however. Despite the fact that we are forecasting up to 18 inches of snow, these numbers are conservative if you trust the NAM. The NAM suggests that 2 feet is reasonable for this event where the heaviest band sets up and where it remains mostly snow. Even LI is not out of the woods for getting these max amounts if the GFS/NAM are indeed correct with the temp profiles. Warnings have been issued for all but the Twin Forks, where the watch has been maintained. This is due to the mixing/rain potential. High winds will also impact the area with the storm. The peak will be Mon and Mon eve. Gusts to around 60 mph still seem likely, especially across eastern LI. Blizzard like conditions can be expected with this storm, especially those areas near the coast that remain all snow. An upgrade to a blizzard warning is not out of the question for portions of the area. Those areas most likely to go blizzard would be coastal CT, NYC, and western LI. After the main snow band lifts north of the area Mon night, there could be additional bands, albeit not as heavy, on the backside of the system right through Tue. The upper low itself passes thru Tue night, allowing for things to dry up by Wed morning."

I will continue to update. I would really like to see the HRRR model agree with the NAM before going all in on the higher snow totals.

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