MD 1397 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR NORTH-CENTRAL UPSTATE NEW YORK
Mesoscale Discussion 1397 NWS Storm Prediction Center Norman OK 1132 PM CDT Sat Jun 21 2025 Areas affected...North-central Upstate New York Concerning...Severe potential...Watch possible Valid 220432Z - 220630Z Probability of Watch Issuance...40 percent SUMMARY...Some risk for large hail and damaging winds may accompany a cluster moving into Upstate New York out of Ontario. Given limited spatial extent of a favorable environment, the need for a watch is not clear. Trends will continue to be monitored. DISCUSSION...A cluster of storms continues to move southeastward through southern Ontario towards Upstate New York. This cluster is moving at about 40 kts. Storms initially developed on the southern flank of a compact shortwave trough and are now being further maintained by a 50 kt low-level jet (evident on the KBUF VAD). Regional observed soundings from this evening show a fairly sharp gradient in mid-level lapse rates with BUF showing near 8 C/km and ALB showing only around 5 C/km. A belt of strong northwesterly flow aloft is promoting over 50 kts of effective shear. Some model guidance from earlier this evening showed some potential for a greater expansion of convection farther east. This, however, should be limited by rapidly decreasing buoyancy. It is more likely that the strongest activity remains on the western flank of the cluster as mid-level lapse rates and elevated buoyancy will slowly increase with time from the northwest. Long hodographs along with the steep mid-level lapse rates will mean some risk of large hail. Damaging winds remain possible as well, but this may only be an isolated threat given at least some low-level CIN exists and potential influence from cooler lake boundary layer. The need for a watch is not certain given the limited area of greater instability downstream of the current activity and that convection may outpace the slow increase in buoyancy through tonight. Trends will be monitored over the next few hours. ..Wendt.. 06/22/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BTV...ALY...BGM...BUF... LAT...LON 43027692 42947763 43367831 44027842 44357698 44577584 44517501 44117472 43427510 43237577 43027692 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN