DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1109 PM CST MON NOV 28 2022
VALID 291200Z - 301200Z
...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS FAR
EAST-CENTRAL LOUISIANA INTO CENTRAL MISSISSIPPI...
..SUMMARY
SEVERE THUNDERSTORMS CAPABLE OF PRODUCING TORNADOES, VERY LARGE
HAIL, AND A FEW SEVERE WIND GUSTS ARE EXPECTED THIS AFTERNOON INTO
THE OVERNIGHT PERIOD ACROSS PARTS OF THE LOWER TO MID MISSISSIPPI
VALLEY AND PARTS OF THE SOUTHEAST. A FEW STRONG TORNADOES WILL BE
POSSIBLE.
..SYNOPSIS
A SURFACE LOW WILL DEEPEN WHILE TRACKING FROM KANSAS TO THE GREAT
LAKES TODAY, ACCOMPANIED BY AN EASTWARD ADVANCING UPPER TROUGH. A
STRONG MID-LEVEL JET STREAM WILL OVERSPREAD AN INTENSE LOW-LEVEL JET
ACROSS THE OH/TN VALLEYS INTO THE SOUTHEAST. AS SUCH, STRONG
DEEP-LAYER FLOW AND SHEAR WILL OVERLAP WITH A MOISTENING,
DESTABILIZING AIRMASS FROM LATE MORNING TO EARLY EVENING FROM THE
LOWER MS VALLEY EAST-NORTHEASTWARD. SEVERAL STRONG TO INTENSE
THUNDERSTORMS ARE EXPECTED TO ORGANIZE AND PROMOTE A RELATIVELY
ROBUST SEVERE THREAT, PARTICULARLY ACROSS THE SOUTHEAST, WHERE
REGIONALLY HIGHER INSTABILITY SHOULD RESIDE.
..PORTIONS OF THE LOWER MS VALLEY TODAY INTO EARLY TONIGHT
STRONG WARM-AIR ADVECTION SHOULD BE UNDERWAY ACROSS THE LOWER MS
VALLEY AT THE START OF THE PERIOD (12Z), WITH RICH BOUNDARY-LAYER
MOISTURE BEING TRANSPORTED NORTHWARD BY A 40-50 KT SOUTHWESTERLY
LOW-LEVEL JET. THROUGH THE DAY, AT LEAST MODEST SURFACE HEATING
SHOULD SUPPORT SURFACE TEMPERATURES RISING INTO THE LOWER 70S F AMID
UPPER 60S F DEWPOINTS WITHIN THE WARM-AIR ADVECTION REGIME, WHERE AN
INCREASE IN THUNDERSTORMS IS ALSO EXPECTED. 50-70 KTS OF
WEST-SOUTHWESTERLY 500 MB FLOW AND 6.5+ C/KM LAPSE RATES WILL
OVERSPREAD THE LOWER MS VALLEY AND THE WARM-AIR ADVECTION REGIME BY
EARLY AFTERNOON, CONTRIBUTING UP TO 1500 J/KG MLCAPE, WHICH IS
ADEQUATE IN SUPPORTING A SEVERE THREAT.
STORMS SHOULD EVENTUALLY ROOT INTO A GRADUALLY DEEPENING BOUNDARY
LAYER DURING THE AFTERNOON, TAKING ADVANTAGE OF THE STRONG
DEEP-LAYER AND LOW-LEVEL SPEED/DIRECTIONAL SHEAR PROVIDED BY THE
OVERLAPPING SOUTHWESTERLY LOW-LEVEL AND WESTERLY MID-LEVEL JETS.
LARGE, CURVED LOW-LEVEL HODOGRAPHS WITH MID/UPPER-LEVEL ELONGATION
WILL SUPPORT WELL OVER 50 KTS OF EFFECTIVE BULK SHEAR, AND 300-400
M2/S2 EFFECTIVE SRH. SUPERCELL STRUCTURES ARE EXPECTED INITIALLY,
WITH LARGE HAIL, TORNADOES, AND A FEW SEVERE GUSTS ALL LIKELY. A FEW
INSTANCES OF 2+ INCH DIAMETER HAIL AND/OR STRONG TORNADOES ARE
POSSIBLE WITH THE MORE ROBUST SUPERCELLS. SHOULD A MORE DOMINANT
SUPERCELL DEVELOP, REMAIN DISCRETE, AND TRAVERSE AN AXIS OF LOCALLY
STRONGER SURFACE HEATING/BUOYANCY, A LONG-TRACKED AND INTENSE
TORNADO MAY OCCUR. THE LATEST HIGH-RESOLUTION GUIDANCE CONSENSUS
SUGGESTS THIS SCENARIO WOULD BE MOST LIKELY ACROSS CENTRAL MS, WHERE
A CATEGORY 4/MODERATE RISK IS IN PLACE. LATER AT NIGHT, STORMS
SHOULD GROW UPSCALE INTO MORE LINEAR SEGMENTS AS THE SURFACE COLD
FRONT AND GREATER LOW-LEVEL CONVERGENCE APPROACHES. DAMAGING GUSTS
SHOULD THEN BECOME THE MAIN THREAT, THOUGH A FEW TORNADOES REMAIN
POSSIBLE.
..PARTS OF THE OH/TN VALLEY INTO EARLY EVENING
A STRONG SURFACE COLD FRONT SHOULD SWEEP ACROSS THE OH/TN VALLEYS
THROUGH THE LATE AFTERNOON AND EVENING HOURS AS THE DEEPENING
SURFACE LOW TRACKS ACROSS THE GREAT LAKES. STRONG CONVERGENCE ALONG
THE COLD FRONT SHOULD FORCE A LOW-TOPPED BAND OF CONVECTION. AMBIENT
TROPOSPHERIC WIND FIELDS WILL BE STRONG, WITH 55+ KTS OF FLOW LIKELY
JUST 1 KM AGL. DOWNWARD MOMENTUM TRANSPORT WITHIN THIS LINE MAY
FOSTER STRONG, OCCASIONALLY DAMAGING GUSTS, WITH A COUPLE OF SEVERE
GUSTS ALSO POSSIBLE, WARRANTING THE INTRODUCTION OF CATEGORY
1/MARGINAL PROBABILITIES THIS OUTLOOK.
..SQUITIERI/DARROW.. 11/29/2022
