ZCZC SPCSWOMCD ALL ACUS11 KWNS 051833 SPC MCD 051833 MEZ000-NHZ000-VTZ000-NYZ000-052030- Mesoscale Discussion 0854 NWS Storm Prediction Center Norman OK 0133 PM CDT Sat Jun 05 2021 Areas affected...Portions of Northern New England Concerning...Severe potential...Watch possible Valid 051833Z - 052030Z Probability of Watch Issuance...40 percent SUMMARY...There is uncertainty in convective evolution in northern New England. A WW is possible this afternoon, but timing is still uncertain. Observational trends will continue to be monitored. DISCUSSION...There remains a fair amount of uncertainty as to the exact evolution of convection this afternoon across northern New England. 12Z CAM guidance presents a wide array of possible outcomes. Trends in surface observations and visible satellite depict at least two plausible scenarios. First, a band of elevated convection near Burlington, VT, continues to move southeastward producing little to no lightning. This features, in some guidance, is forecast to intensify as it encounters greater instability to the southeast near the southern Maine and New Hampshire. In those locations, temperatures have already risen to near 90 F with dewpoints currently holding in the upper 50s to low 60s F. Another area of potential development is likely in northern New Hampshire into adjacent portions of Maine along a differential heating boundary. There, cumulus have continued to deepen of the last hour and that trend should continue. Given the steep low-level lapse rates and moderate flow off the surface, strong/damaging wind gusts are the primary threat with storms this afternoon. Objectively analyzed 40-50 kts of effective shear will promote organized storms, some perhaps supercellular. Discrete storms would be capable of marginally severe hail and perhaps a tornado. A WW is possible this afternoon, though timing is uncertain. Observational trends would suggest development in perhaps 2-3 hours. These trends will continue to be monitored. For portions of northern Maine, uncertainty is higher given remaining cloud cover and cooler temperatures. The most probable scenario in this region is that storms will initiate somewhere in the St. Lawrence River vicinity and move southeastward into the region. This activity would more likely occur later this afternoon given the inhibition that is yet to be overcome. ..Wendt/Guyer.. 06/05/2021 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CAR...GYX...BTV... LAT...LON 44147415 44697256 45066974 45146881 44686841 44096931 43687017 43447051 43367120 44147415 NNNN