Subj : DAY3SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Mar 21 2024 07:30:39 ACUS03 KWNS 210730 SWODY3 SPC AC 210729 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Thu Mar 21 2024 Valid 231200Z - 241200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS EARLY SATURDAY ACROSS PARTS OF SOUTHERN FLORIDA AND PARTS OF COASTAL NORTH CAROLINA... ....SUMMARY... Strong thunderstorms posing at least some risk for severe weather may approach or perhaps spread inland across the Outer Banks vicinity of North Carolina early Saturday, as the risk for strong to severe thunderstorm development diminishes across parts of southern Florida. ....Synopsis... As a more progressive regime continues to spread across the central into eastern mid-latitude Pacific, blocking initially centered over the northeastern Pacific is forecast to gradually begin to breakdown. As this occurs, models suggest that downstream flow may undergo amplification across the southern mid- and subtropical latitudes, inland of the Pacific coast into the western Atlantic. It appears that this will include large-scale mid-level troughing digging across the Pacific coast through the Southwest, with at least a couple of significant embedded short wave perturbations. This will be preceded by building ridging across the Great Plains into Mississippi Valley, and digging mid-level troughing offshore of the southern Atlantic Seaboard. In higher latitudes, a vigorous short wave impulse turning eastward across the Great Lakes by 12Z Saturday (to the south of an elongating circulation across southern Hudson Bay into northern Manitoba) is forecast to accelerate east-northeastward through much of the St. Lawrence Valley by early Sunday, trailed by a perturbation emerging from the troughing to the south. Initially accelerating northeastward to the lee of the southern Appalachians at the outset of the period, there appears increasing consensus that this trailing impulse may support a compact deepening surface low, within elongating surface troughing mostly offshore of the Atlantic coast. However, there is considerable lingering spread concerning this and other sub-synoptic developments across and east of the Atlantic Seaboard. In the wake of the developing surface low, a significant ongoing cold intrusion to the lee of the Rockies is forecast to overtake the offshore surface troughing late Saturday through Saturday night. Models indicate that the southwestern flank of this cold air will stall and begin to undergo modification across the lower Mississippi Valley into central high plains, as surface troughing begins to deepen to the lee of the Front Range and southern Rockies. ....Florida... It is possible that an outflow boundary may linger across parts of the southern peninsula and/or Florida Keys into Saturday morning, with potential for continuing vigorous thunderstorm development accompanied by at least some risk for strong, gusty winds. It appears that this boundary will shift off to the east and south by midday, if not earlier. In its wake, models indicate low-level flow quickly veering to an increasingly westerly component across the remainder of the peninsula, leading to diminishing convective potential ahead of a weak approaching cold front. ....Eastern North Carolina... Severe weather potential appears largely conditional, depending on the evolution and track of the primary surface low. However, the inland advection of a moist unstable warm sector appears at least possible early Saturday, within a strongly sheared environment across the Outer and Inner Banks vicinity. This may provide a window of opportunity for organized convective development, including supercells. ...Kerr.. 03/21/2024 $$ = = = To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .