Day 1 Severe Weather Outlook

Valid 252000Z – 261200Z

…THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER SOUTHEAST
LOUISIANA…AND SOUTHERN MISSISSIPPI/ALABAMA…

…SUMMARY…
A couple tornadoes and isolated damaging winds will be possible
through tonight across portions of the central Gulf Coast States.

No changes were made to the previous outlook. The greatest threat
during the daytime will continue to be over southwest AL into
southern MS, south of the warm front. Here, effective SRH of 150-200
m2/s2 along with surface based instability in excess of 1000 J/kg
may prove sufficient for a couple supercells with brief tornado
threat prior to storms becoming elevated. To the north and west,
extensive cloud cover and precipitation remains, but persistent
southerly winds just off the surface will aid warm front movement
tonight across eastern LA into MS. Although warming aloft will
continue south of the shortwave trough, shear profiles will remain
strong and conditionally favorable for supercells, with a tornado
possible.

..Jewell.. 10/25/2019

.PREV DISCUSSION… /ISSUED 1120 AM CDT Fri Oct 25 2019/

…Central Gulf Coast States…
Two rounds of potential severe are anticipated during the period.
The first round is ongoing within the warm conveyor region centered
across the MS/AL coast. With mid to upper 70s surface dew points
offshore and low 70s having reached the coast, slow northward
surface-based destabilization is anticipated across southeast MS and
southwest AL. A few supercells have been observed this morning,
mainly in the coastal waters. This activity should continue to shift
slowly north as a diffuse warm front advances. The greatest relative
tornado threat should exist across southwest AL and southeast MS
amid 25-30 kt 0-1 km shear prior to individual cells weakening with
northern extent in a cooler/more stable boundary layer north of the
front. The severe threat within this warm conveyor regime should
subside towards early evening.

A second round of tornado/wind potential may redevelop tonight as
cyclogenesis occurs in the northwest Gulf with the resultant low
tracking north-northeast into the Lower MS Valley. The primary
uncertainty will be the northward extent of surface-based
destabilization given the time of day along with extensive prior
convection. However, low-level wind profiles will be substantially
stronger compared to this afternoon yielding rather enlarged
low-level hodographs. Have expanded level 1 and 2 severe risk areas
to the west/north near the surface cyclone track to account for this
relatively more conditional threat.

$$

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