My Personal Weatherman™
Damaging Wind Gusts, Large Hail, and Tornado Threat Tomorrow For Long Island
This image shows the threat of tornadoes, damaging wind gusts, and large hail from left to right, respectively for tomorrow into tomorrow night.
Probability of damaging thunderstorm winds or wind gusts of 50 knots (57.5 mph) or higher within 25 miles of a point. Hatched Area: 10% or greater probability of wind gusts 65 knots (74.8 mph) or greater within 25 miles of a point.
Probability of one inch diameter hail or larger within 25 miles of a point. Hatched Area: 10% or greater probability of two inch diameter hail or larger within 25 miles of a point.
Probability of a tornado within 25 miles of a point.
From the Storm Prediction Center for the northeast/mid-Atlantic:
Initial afternoon storm development will likely be supercellular, with both a large hail and damaging wind threat. Some of the large hail could be significant (2+ inches) given somewhat steepened mid-level lapse rates and very favorable thermodynamic/kinematic environment. Clustering and upscale growth appears possible later Thursday afternoon as storms approach NYC and southern New England. A more substantial severe/damaging wind threat will likely develop as this mode transition occurs.
The 2nd and 3rd images are the simulated radar from the NAM and HRRR models for 10 PM tomorrow, but the timing of the storms may be a little sooner than the models are showing.
From the National Weather Service covering Long Island and the tri-state area:
By the mid to late afternoon strong to severe storms are expected to begin popping up to our north, and then move southeast into the early and late evening hours. Sufficient CAPE of 1500-2500 j/kg along with more than sufficient bulk shear of 40 to 45 kts should create an environment where storms will be able to maintain themselves as they move southeast closer to the coast. Hodographs indicate various convective modes are possible, with discrete cells to the north likely quickly giving way to more linear and potential bowing segments, along with supercell mode. One of the more impressive indicators for robust updraft development are steeper than usual mid level lapse rates across our region, with mid lapse rates perhaps approaching 7 c /km based on various guidance. A variety of hazards are highlighted for this potential severe episode with strong to damaging winds, and large hail potential, especially in discrete cell mode initially mainly for northern sections. There is for the time being very good agreement among the convective allowing models with only some subtle timing differences, with NAM based guidance running a bit late as usual with the timing.
Hatched Area: 10% or greater probability of wind gusts 65 knots or greater within 25 miles of a point