Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Mar 18 2024 16:28:39 ACUS01 KWNS 181628 SWODY1 SPC AC 181626 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Mon Mar 18 2024 Valid 181630Z - 191200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON ACROSS CENTRAL FL AND MUCH OF THE FL ATLANTIC COAST... ....SUMMARY... Isolated large hail and wind damage is possible this afternoon across central Florida and along much of the Florida Atlantic coast. ....Central and eastern Florida Peninsula... Morning water-vapor imagery indicates a shortwave trough over the middle MS Valley digging southward into the base of a larger-scale trough. This evolution will allow a related cold front to continue southward across the central/southern FL Peninsula today. While the FL Peninsula will generally be displaced from the associated midlevel height falls/large-scale ascent, afternoon storm development will be aided by ascent along the shallow frontal zone and diurnal heating of a moist boundary layer amid leftover outflow boundaries from morning convection. The development of 40-50-kt effective shear (characterized by a long/mostly straight hodograph) will support a mix of organized multicells and transient supercells along/ahead of the southward-moving front and mesoscale boundaries over the warm sector. These storms will be aided by relatively steep midlevel lapse rates atop a moist/destabilizing boundary layer. A deep CAPE profile (with moderate surface-based buoyancy) and the aforementioned hodograph will support large hail up to 1.75 inches and locally severe gusts near 60 mph with any sustained/organized storms. Additionally, a brief tornado cannot be entirely ruled out along the east coast, where locally backed flow may contribute to slightly more low-level hodograph curvature. However, veered low-level flow ahead of the front (along with a lack of large-scale ascent) and deep westerly flow may both limit the coverage of organized storms, and convective residence time in the most favorable environment -- warranting the maintenance of the Marginal risk. ....Arizona and southern California... A mid/upper-level low centered over west-central AZ will move slowly westward into southern CA today. On the eastern periphery of this feature, 25-30-kt midlevel southeasterlies combined with cold temperatures aloft/steep midlevel lapse rates could favor a couple strong/loosely organized storms capable of mainly small hail and locally strong gusts. Along the northern and western periphery of the upper low, a stronger belt of midlevel flow (around 45 kt) accompanying a westward-moving impulse will overspread west-central AZ into southern CA this afternoon. Over parts of southern CA (particularly west of the Desert), upper 40s/lower 50s dewpoints beneath the steep lapse rates will contribute to more substantial buoyancy amid 30-40 kt of effective shear. While convective evolution/sustenance is uncertain given offshore/downslope flow across this area, there is a conditional risk of near-severe hail and gusty winds if any longer-lived storms develop. Overall, confidence in this scenario is too low to add unconditional 5-percent hail/wind probabilities with this outlook. ...Weinman/Goss.. 03/18/2024 $$ = = = 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) .