weathermedic

Good read from Upton's morning AFD: Regarding the potential for a coastal storm for this upcoming weekend, if any impacts were to occur it appears that the timing would be late Saturday night and into Sunday, and possibly Sunday evening. Most of the dynamic modeling has the storm being the nearest of misses, or a side swipe / brush for eastern sections east of the NYC metro. The longwave pattern does amplify, but the mean eastern trough also begins to progress east while amplifying. At this point in the modeling / forecast process the most likely scenario is the nearest of misses, or perhaps the region gets bisected with a sharp cut off in moisture / QPF. With an eastern track and arctic air in place beforehand precipitation would in the form of all snow. Most of the modeling on most of the more recent runs has had the main 500 mb vorticity maximum pass just south of Cape Hatteras would typically means a miss for our region with heavy snowfall. However the slightest misrepresentation of the upper levels by NWP would have massive consequences in terms of sensible weather, especially further east across the region. Strong winds remain a distinct possibility, especially further east. Stay tuned because changes in the forecast for the second half of the weekend remain in play.

9.5 inches here with about .5 of that as sleet

Looks like gravity waves on radar

Another 1.8 inches in the past hour for a total of 8.1 inches so far

Meanwhile at the southern end of this huge precipitation shield covering the country, tornado watches up for AL, GA and FL

Co-worker in Medford NJ reporting sleet now

Just measured 2 inches in the last hour. Total up to 6.3 inches now here in Sheepshead Bay Brooklyn

I just measured 4.25 inches at my station in Sheepshead Bay Brooklyn

3 inches at my location in Sheepshead Bay

Also don't forget if cities/towns just use plain salt, it does not have the same melting power when temps get below 20 degrees. I know NYC Sanitation salt trucks have the ability to mix in liquid calcium chloride when they spread so that should help

NYC Sanitation just gave the order for all their trucks to drop their plows and commence plowing operations. Had one just come down my block. That layer of salt they spread last night did nothing as the road is still white after the plow went by.

Latest graphic from Upton

Bernie Rayno with a nice explanation on things https://x.com/AccuRayno/status/2015106637212659787?ref_src=twsrc^tfw|twcamp^tweetembed|twterm^2015106637212659787|twgr^c7b51d61c8a3e5047944a1f086a006052f31bce0|twcon^s1_c10&ref_url=https%3A%2F%2Fpublish.twitter.com%2F%3Furl%3Dhttps%3A%2F%2Ftwitter.com%2FAccuRayno%2Fstatus%2F2015106637212659787

Meanwhile barometer is still rising at 30.64 (approx 1038 mb)

Good write up (as usual) with the morning AFD out of Upton: A major winter storm will impact the region Sunday into at least early Monday. A Winter Storm Warning Remains in effect for the entire area. Arctic air has settled over the area courtesy of a sprawling 1048 mb high pressure over the northern plains. This high pressure will settle over New England tonight as a winter storm materializes over the southeastern US. Low pressure will develop over the south and be forced to track around the deep cold air damming signature east of the Appalachians tonight, with secondary low development taking place along the Middle Atlantic coast on Sunday. This low pressure will then deepen as it tracks towards the Long Island coast late Sunday into Sunday night before shifting offshore on Monday. The main uncertainty with the system continues to revolve around the timing of potential mixing with sleet for the southern/coastal portion of the region Sunday evening. The model guidance is in overall agreement on the key pieces with the winter storm, but differ slightly on the northward extent and timing of a warm nose around 750 mb. Generally took a blend of partial thicknesses from the GFS, ECMWF, NAM, and RGEM Sunday evening. Most of the guidance has settled on any potential wintry mix occurring around or just after 00z Monday. The NAM is the most aggressive and quickest with the warm nose (sometime mid to late afternoon) and wanted to at least blend its thicknesses in case the warm nose comes in a bit faster than currently expected, which has happened in past events. Snow will quickly develop from south to north across the area Sunday morning as the region lies underneath an intense polar jet streak lifting into southeast Canada. The snow will fall into arctic air with surface temperatures only in the low to mid teens. This is a bit unusual for the area as most snow events over the Tri-State occur with temperatures in the 20s or low 30s. The snow will quickly accumulate as the intensity picks up through the morning. Mid level thermal forcing will increase over the area, especially heading into the afternoon. The 850-700 mb frontogenesis is impressive and the overall deep layer of vertical velocities over the area strongly support heavy snow over the region in the afternoon. Only a slight increase in temperatures is expected in the afternoon, except the southern half of the area where temperatures rise into the mid 20s. As the warming in the middle levels continues, the chance for a mix with sleet near the coast increase sometime late in the afternoon or evening. It needs to be emphasized that the overall impacts will not change and significant snow will occur before any wintry mix. There is a possibility the heavy snowfall rates will be able to hold back the warm nose just enough or create an isothermal layer on the 0C isotherm to prolong heavy snow for even just an hour two. The 00z HREF indicated several hours of over a 60 percent chance of greater than 1 inch per hour rates, and even has a few hours over 80 percent. The probability for greater than 2 inches per hour on the HREF in the afternoon/early evening ranges from 20 to 40 percent. The guidance also offers impressive QPF values between 18z Sunday and 00z Monday with potential of at least a half inch liquid, giving more confidence there will be heavy snowfall over the area. A few lightning strikes cannot be ruled out in the heaviest bands with the impressive dynamics aloft and deep moisture being lifted over the low level arctic air. The strong mid level frontogenesis lifts northeast between 00-06z Monday and this should serve to gradually reduce precip rates. There may also be drying aloft, which will start to reduce snowfall rates where it remains all snow. The southern half of the area should see a wintry mix of sleet, potentially mixed with snow if the warm nose is not as deep. There is also a chance for some light freezing rain and a light glaze of ice as the drying aloft occurs, cutting off snow growth along with the thinning of the depth of the low level cold air. This may also be dependent on how close the low pressure ends up to Long Island. The consensus of the modeling keeps the low just south and east of Long Island, but if it were to end up closer to the shore, some parts of eastern Long Island could briefly rise above freezing with light plain rain briefly possible. The system starts pulling away from the area late Sunday night into Monday morning. Some bands of light snow may return as the trailing upper trough approaches and the thermal profiles become colder heading into Monday. Probabilities for precip decrease significantly Monday afternoon and there is potential anything that falls may just be flurries. Snowfall totals are largely consistent with the previous forecast ranging from around 10 inches near the coast and around 16 inches well inland. The potential of sleet is included in these totals for areas that may see a mix or a full changeover. SLRs are tricky with this event as the arctic air mass supports a higher ratio (around or just above 15:1), especially early in the event. The increasing moisture aloft and warmer air in the middle levels will likely lower ratios to 12-14:1 and will drop further with any mixing in the evening towards the coast. As noted above, snowfall rates of 1-2 inches per hour are expected in the afternoon and early evening. Winds will pick up in the afternoon and evening, especially near the coast and could create near white-out conditions/near blizzard conditions with winds gusting 30 to 40 mph at times. A mix or change to sleet will reduce this potential as visibilities would not be as low.