Severe Storms | disasterassistance.gov

SPC Aug 6, 2024 2000 UTC Day 1 Convective Outlook

1 year 1 month ago

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Tue Aug 06 2024 Valid 062000Z - 071200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN OHIO AND NORTHERN PENNSYLVANIA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF MONTANA...WYOMING AND SOUTH DAKOTA...THE CAROLINAS...AND ARIZONA... ...SUMMARY... Severe thunderstorms capable of damaging winds, hail, and isolated tornadoes will continue across northern Ohio into New Jersey this afternoon and evening. Others areas of concern include much of Montana into western South Dakota, the coastal Carolinas, and across parts of Arizona. ...20z Update... Minimal changes have been made to the current outlook to adjust for ongoing thunderstorms. Multiple rounds of strong to severe storms are ongoing over parts of the Upper OH valley and Great Lakes. Additional development is expected farther west this afternoon and evening with a risk for some upscale growth. The risk for damaging winds and a couple of tornadoes continues. Across the Carolinas, spiral bands associated with TS Debby will continue to mover inland as the central low drifts east/northeast. Minor clearing has been noted in the precip shield allowing for weak heating in between the better defined bands. Occasional stronger convective cells developing over the Atlantic will remain capable of a couple tornadoes as they move inland into relatively strong low-level shear near the NC/SC border. Thunderstorm developing off the higher terrain in central AZ will be capable of gusty winds and small hail as they move west/southwest later this afternoon. The Marginal area was shifted slightly north to better encompass some of the initial storm development. Otherwise the previous forecast areas remain largely unchanged, see the prior discussion for more information. ..Lyons.. 08/06/2024 .PREV DISCUSSION... /ISSUED 1127 AM CDT Tue Aug 06 2024/ ...OH to NJ... Recent water vapor loop shows a well-defined and fast-moving shortwave trough over Lower MI. This feature will track eastward across parts of OH/PA/NY today, along a corridor of strong heating/destabilization. This will lead to multiple clusters of intense convection capable of damaging winds, large hail. Winds aloft are seasonably strong, but low-level winds are relatively weak. Some increase in low-level winds/shear may occur later today, posing some risk of isolated tornadoes as well. ...MT/WY/SD... Multiple minor shortwave troughs will rotate through the top of the ridge over MT/WY today, while mid-level winds strengthen. A plume of mid-level moisture/lift ahead of these features will lead to scattered thunderstorms over the mountains of western MT by mid afternoon. This activity will spread into the adjacent Plains and intensify. Forecast soundings show sufficient deep-layer shear to support supercell storm structures capable of large hail and damaging wind gusts through the afternoon and evening. ...AZ... A weak upper low is present this morning over northern Mexico tracking slowly westward. Enhanced easterly mid level winds around the northern periphery of the low are spreading westward across AZ today. A few clusters of thunderstorms are likely to form over the mountains of eastern AZ and propagate westward through the evening into the lower deserts. This pattern appears favorable for a more organized damaging wind event across parts of AZ, although the details of thunderstorm coverage/intensity over the higher terrain of eastern AZ will help dictate the overall threat later today. ...Carolinas... TS Debby remains over southeast GA, with bands of offshore thunderstorms tracking inland along the coasts of SC/southeast NC. Sufficient low-level shear will remain in place through the afternoon and evening for a risk of transient mesocyclones and a few tornadoes through the forecast period. Read more