Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS02 KWNS 050528
SWODY2
SPC AC 050527

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1227 AM CDT WED AUG 05 2015

VALID 061200Z - 071200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM ERN SD INTO SWRN MN AND
ADJACENT AREAS OF IA AND NEB...

...THERE IS A MRGL RISK OF SVR TSTMS OVER PARTS OF THE CNTRL AND NRN
PLAINS...

...THERE IS A MRGL RISK OF SVR TSTMS FROM THE TN VALLEY TO THE OUTER
BANKS OF NC...

...SUMMARY...
A FEW SEVERE THUNDERSTORMS WITH THE POTENTIAL FOR HIGH WINDS AND
HAIL MAY DEVELOP ACROSS EASTERN PARTS OF THE DAKOTAS...WESTERN
MINNESOTA...AND ADJACENT AREAS OF NEBRASKA AND IOWA ON THURSDAY.
OTHER STRONG TO ISOLATED SEVERE STORMS WILL BE POSSIBLE FROM THE
TENNESSEE VALLEY EASTWARD ACROSS THE APPALACHIANS TO THE
MID-ATLANTIC COAST.

...OVERVIEW...
A BROAD SUBTROPICAL RIDGE WILL DOMINATE THE S-CNTRL U.S. WITH A
NUMBER OF SHORTWAVE IMPULSES MOVING AROUND THE PERIPHERY OF THE
RIDGE AND EMBEDDED WITHIN 30-40KT MIDLEVEL FLOW. ONE OF THE STRONGER
DISTURBANCES WAS TRACKING ACROSS NRN CA EARLY TODAY. LATEST GUIDANCE
TAKES THIS IMPULSE E-NEWD ACROSS THE NRN GREAT BASIN AND THEN TO THE
NRN HIGH PLAINS BY THE START OF THE FORECAST PERIOD/THURSDAY
MORNING. DPVA AND MIDLEVEL HEIGHT FALLS ACCOMPANYING THIS SYSTEM
WILL INDUCE SURFACE LOW DEVELOPMENT ACROSS THE NRN PLAINS AND THE
LOW IS THEN EXPECTED TO TRACK FROM THE WRN DAKOTAS TO MN DURING
THURSDAY.

FARTHER SOUTH AND EAST...RESIDUAL SYNOPTIC FRONT...FRACTURED BY
NUMEROUS CONVECTIVE OUTFLOWS/COLD POOLS...WILL REMAIN A FOCUS FOR
WEAK SURFACE WAVE DEVELOPMENT FROM THE MS RIVER EAST TO THE OUTER
BANKS OF NC. SURFACE DEVELOPMENT AND MORE CONCENTRATED/DEEPER ASCENT
ALONG THIS BOUNDARY MAY BE SUPPORTED BY A COMPLEX OF MIDLEVEL
SHORTWAVE TROUGHS FORECAST TO SPREAD WEAK HEIGHT FALLS EASTWARD FROM
THE TN VALLEY TO THE SOUTHEAST THROUGH THE DAY AND EVENING THURSDAY.

...ERN SD INTO SWRN MN AND NWRN IA...
MODEST TO STRONG ASCENT SHOULD ACT ON AN INCREASINGLY UNSTABLE
AIRMASS ACROSS THE CNTRL AND NRN PLAINS DURING THE DAY. STRONG TO
ISOLATED SEVERE STORMS WITH HAIL MAY BE ONGOING AT THE START OF THE
PERIOD WITHIN WARM CONVEYOR BELT SITUATED FROM NEB TO ND. AS SURFACE
LOW DEVELOPS EAST THROUGH THE DAY...WARM SECTOR ON THE EDGE OF
PLAINS CAPPING INVERSION SHOULD BECOME AT LEAST MODERATELY UNSTABLE
GIVEN LOW-MID 60S F DEWPOINTS AND STEEPENING MIDLEVEL LAPSE RATES ON
THE ORDER OF 7 C/KM. LIFT ASSOCIATED WITH THE LOW AND WARM FRONT
SHOULD BE SUFFICIENT FOR ADDITIONAL STORM DEVELOPMENT IN THE
PRESENCE OF ADEQUATE SHEAR FOR STORM ORGANIZATION. MOST SUPPORTIVE
JUXTAPOSITION OF CAPE/SHEAR AND DYNAMIC FORCING WITHIN LEFT EXIT
REGION OF MIDLEVEL JET IS FORECAST TO OCCUR DURING LATE AFTERNOON
AND EVENING FROM ERN SD INTO SWRN MN AND ADJACENT AREAS OF NEB/IA. A
FEW SUPERCELLS APPEAR POSSIBLE IN THESE AREAS...PERHAPS CONGEALING
INTO A FORWARD-PROPAGATING MCS WITH TIME. HAIL AND SOME TORNADO
POTENTIAL MAY EVOLVE FROM INITIALLY DISCRETE CONVECTION BEFORE ONSET
OF POSSIBLY MORE LINEAR MODE RESULTS IN AN INCREASED CHANCE FOR
DAMAGING WINDS. LACK OF GREATER DESTABILIZATION WITH EWD EXTENT
SUGGESTS OVERALL SEVERE WIND RISK MAY BE PRIMARILY CONFINED TO LATE
AFTERNOON AND EVENING.

...TN VALLEY TO COASTAL NC...
LATEST GUIDANCE IS MORE PROGRESSIVE WITH THE EWD MOVEMENT OF THE
ELONGATED COMPLEX OF SHORTWAVE TROUGHS CURRENTLY SITUATED ACROSS THE
CNTRL AND SRN PLAINS. THESE IMPULSES WILL CONTINUE EAST ON THURSDAY
AND SHOULD AID IN POCKETS OF STRONGER ASCENT AND STORM INITIATION AS
VERY MOIST AND WEAKLY CAPPED AIRMASS UNDERGOES DIURNAL
DESTABILIZATION. GENERALLY WEAK LAPSE RATES AND MARGINAL SHEAR WILL
LIMIT GREATER SEVERE WEATHER POTENTIAL. HOWEVER... STORM
COVERAGE/MULTICELL MERGERS...AND SOME POTENTIAL FOR LOCALLY GREATER
DESTABILIZATION IN AREAS WITH STRONGER HEATING...COULD SUPPORT A FEW
WET DOWNBURST EVENTS.

..CARBIN.. 08/05/2015



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