810
ACUS03 KWNS 070732
SWODY3
SPC AC 070731
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0231 AM CDT TUE JUL 07 2020
VALID 091200Z - 101200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE UPPER
MIDWEST INTO THE CENTRAL PLAINS AND OZARK PLATEAU...
..SUMMARY
ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE FROM THE UPPER MIDWEST
INTO THE CENTRAL PLAINS AND OZARK PLATEAU ON THURSDAY.
..UPPER MIDWEST INTO THE CENTRAL PLAINS/OZARKS
LOCATION OF THE GREATEST SEVERE WEATHER POTENTIAL ON THURSDAY WILL
DEPEND LARGELY ON THE ORGANIZATION AND LONGEVITY OF ANTECEDENT
THUNDERSTORMS. MODEL GUIDANCE IS IN GOOD AGREEMENT THAT AN ORGANIZED
CONVECTIVE LINE WILL BE IN ITS DISSIPATION STAGE OVER THE LOWER MO
VALLEY EARLY THURSDAY. OUTFLOW BOUNDARY ASSOCIATED WITH THIS SYSTEM
WILL THEN SERVE AS THE PRIMARY LOCATION FOR CONVECTIVE DEVELOPMENT
THURSDAY AFTERNOON AND EVENING. BASED ON CURRENT MODEL PROGS, THIS
INITIATION WOULD OCCUR FROM CENTRAL KS EASTWARD INTO SOUTHERN MO.
HOWEVER, MESOSCALE NATURE OF THIS SCENARIO INTRODUCES SIGNIFICANT
UNCERTAINTY AT THIS FORECAST RANGE, RESULTING IN THE INTRODUCTION OF
ONLY 5% SEVERE PROBABILITIES.
THE OVERALL PATTERN, WITH A RIDGE BUILDING ACROSS THE SOUTHWEST AND
A BELT OF ENHANCED UPPER FLOW FROM THE GREAT BASIN THROUGH THE MID
MS VALLEY, SUGGESTS THE POTENTIAL EXISTS FOR A CONVECTIVE LINE TO
INITIATE OVER THE CENTRAL HIGH PLAINS AND THEN MOVE
EASTWARD/SOUTHEASTWARD OVERNIGHT. HOWEVER, AS WITH THE THREAT
DISCUSSED IN THE PREVIOUS PARAGRAPH, PREDICTABILITY IS LIMITED BY
THE NUMEROUS MESOSCALE FACTORS INVOLVED IN THE DEVELOPMENT OF SUCH A
CONVECTIVE LINE. THIS LIMITED PREDICTABILITY IS EVIDENCED BY THE
WIDE RUN-TO-RUN AND MODEL-TO-MODEL VARIABILITY IN THE DEVELOPMENT
AND LOCATION OF THE LINE. GIVEN ALL OF THESE FACTORS, ELECTED TO
INCLUDE A BROAD 5% PROBABILITY WITH THE EXPECTATION INCREASED
PROBABILITIES WILL LIKELY BE NEEDED IN SUBSEQUENT OUTLOOKS AS THE
PREDICTABILITY IMPROVES.
LASTLY, A WEAK COLD FRONT IS EXPECTED OVER THE UPPER MIDWEST,
CONTRIBUTING TO SCATTERED THUNDERSTORM DEVELOPMENT THURSDAY
AFTERNOON. VERTICAL SHEAR WILL BE WEAK BUT MODERATE TO STRONG
INSTABILITY IS STILL EXPECTED TO RESULT IN A FEW STRONGER STORMS.
..CAROLINAS/VA TIDEWATER
A SURFACE LOW IS FORECAST TO BE JUST OFF THE CAROLINA COAST EARLY
THURSDAY MORNING. SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS THE
CAROLINAS AND INTO PORTIONS OF SOUTHEAST VA DURING THE DAY.
STRENGTHEN/MATURING OF THIS LOW WILL RESULT IN ENHANCED LOW TO
MID-LEVEL FLOW THROUGHOUT ITS EASTERN PERIPHERY. HOWEVER, ALL THE
GUIDANCE CURRENTLY KEEPS THIS REGION OFFSHORE, LIMITING THE SEVERE
POTENTIAL OVER LAND AREAS.
..MOSIER.. 07/07/2020
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