Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS03 KWNS 040648
SWODY3
SPC AC 040647

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0147 AM CDT TUE AUG 04 2015

VALID 061200Z - 071200Z

...THERE IS A MRGL RISK OF SVR TSTMS OVER PORTIONS OF THE MID SOUTH
FROM ERN AR TO NRN AL...

...THERE IS A MRGL RISK OF SVR TSTMS OVER PORTIONS OF THE NRN PLAINS
FROM ERN SD INTO MN/IA...

...SUMMARY...
ISOLATED STRONG THUNDERSTORMS WILL BE MOST LIKELY FROM PORTIONS OF
LOWER-MIDDLE MISSISSIPPI RIVER VALLEY EAST TO THE CENTRAL
APPALACHIANS AND MID-ATLANTIC ON THURSDAY. ANOTHER AREA WITH THE
LIKELIHOOD FOR ISOLATED STRONG STORMS WILL BE ACROSS THE NORTHERN
PLAINS AND UPPER MISSISSIPPI VALLEY.

...OVERVIEW...
WLY/NWLY MIDLEVEL FLOW AOB 40KT WILL EXIST FROM THE NRN HIGH PLAINS
ESEWD ACROSS THE MIDDLE MS VALLEY AND EAST TO MID-ATLANTIC COAST. A
FEW DISTURBANCES ARE FORECAST TO BE EMBEDDED WITHIN THIS BELT OF
WEAK TO MODEST FLOW. THE STRONGEST OF THESE WILL BE A SHORTWAVE
TROUGH EJECTING EAST ACROSS MT DURING THE DAY. DOWNSTREAM FROM THIS
STRONGER IMPULSE...AN ELONGATED SHORTWAVE TROUGH...PARTLY RESULTING
FROM A NUMBER OF MCV MERGERS...WILL MOVE EAST ACROSS THE CNTRL TO
NRN PLAINS FROM THURSDAY AFTERNOON THROUGH FRIDAY MORNING. ANOTHER
MCV/SHORTWAVE IMPULSE OVER THE MID/LOWER MS VALLEY WILL SPREAD EAST
TO THE TN VALLEY DURING THE DAY. GENERALLY WEAK FORCING FOR ASCENT
WITH THESE DISTURBANCES WILL COMBINE WITH DIURNAL DESTABILIZATION TO
PROMOTE STRONG TO ISOLATED SEVERE WEATHER DURING THURSDAY AFTERNOON
AND EVENING.

...MID SOUTH...
EXPECT STRONG DESTABILIZATION TO OCCUR ALONG THE SWRN FLANK OF
DECAYING MCS FROM ERN AR TO ADJACENT AREAS OF NRN MS DURING THE
MORNING/EARLY AFTERNOON. STRONG CAPPING PERSISTING ACROSS THESE
AREAS MAY PROHIBIT MORE WIDESPREAD STORM DEVELOPMENT. HOWEVER...
DEGREE OF INSTABILITY IN THE PRESENCE OF PERSISTENT AND FOCUSED LOW
LEVEL CONVERGENCE...IN COMBINATION WITH MODEST TO LOCALLY STRONG
SPEED/DIRECTIONAL SHEAR...SUGGEST AT LEAST A MARGINAL AND
CONDITIONAL RISK OF SEVERE STORMS.

...NRN/CNTRL PLAINS...
WARM ADVECTION AND INCREASING DEEP-LAYER FORCING FOR ASCENT WILL
DEVELOP ACROSS THESE AREAS THROUGH THE PERIOD AS A LEADING/WEAK
SHORTWAVE TROUGH MOVES EAST AND IS QUICKLY FOLLOWED BY A STRONGER
IMPULSE SPREADING EAST FROM MT THROUGH THURSDAY NIGHT. STRONG
DESTABILIZATION SHOULD OCCUR ON THE FLANK OF RESIDUAL MCS
OUTFLOW/DEVELOPING WARM FRONT FROM ERN SD INTO MN DURING THE DAY.
LIFT ACROSS THE REGION WILL THEN INCREASE INTO THE EVENING AS THE
NEXT SYSTEM MOVES EAST AND HEIGHT FALLS INDUCE SURFACE WAVE
DEVELOPMENT ON THE FRONT ACROSS ERN SD. SEVERE WEATHER RISK SHOULD
EVOLVE AND PERSIST INTO THE EVENING GIVEN THE DEVELOPING SURFACE LOW
AND STRENGTHENING FLOW/SHEAR ACROSS THE REGION.

..CARBIN.. 08/04/2015




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