[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 051638
SWODY1
SPC AC 051636

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1136 AM CDT SAT AUG 05 2006

VALID 051630Z - 061200Z

...THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON INTO EARLY
TONIGHT ACROSS THE ERN DAKOTAS AND MN....

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK
AREA...FROM THE NRN PLAINS TO THE UPPER MS VALLEY....

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON FROM LA/SRN MS
TO CENTRAL GA AND SC....

...NRN PLAINS AND UPPER MS VALLEY THROUGH TONIGHT...
A STRONG MID LEVEL SHORTWAVE TROUGH OVER SRN SASKATCHEWAN WILL MOVE
EWD OVER ND/SRN MANITOBA TODAY AND INTO WRN ONTARIO/NRN MN TONIGHT. 
AN ASSOCIATED SURFACE COLD FRONT ACROSS WRN ND THIS MORNING WILL
MOVE SEWD ACROSS ERN ND AND CENTRAL SD BY THIS EVENING...REACHING
AN AXIS FROM CENTRAL NEB TO NW IA TO NW WI BY 06/12Z.  A SEPARATE
LEE CYCLONE IN SW SD WILL GRADUALLY FILL AND DRIFT SWD/SEWD THROUGH
TONIGHT.  THE COLD FRONT IS EXPECTED TO BE THE PRIMARY FOCUS FOR
SEVERE THUNDERSTORM DEVELOPMENT LATER THIS AFTERNOON INTO EARLY
TONIGHT.

THE REMNANTS OF OVERNIGHT CONVECTION...ASSOCIATED WITH AN INITIAL
MID LEVEL WAVE NOW MOVING OVER MN/IA...PERSIST OVER SRN IA. 
BOUNDARY LAYER DEWPOINTS IN THE LOW-MID 60S ARE RETURNING NWD ACROSS
THE ERN DAKOTAS TO THE W OF THIS CONVECTION...THOUGH THE RICHEST
MOISTURE IS CONFINED TO AREAS FROM ERN KS SWD TO THE GULF COAST. 
ANOTHER MINOR MID LEVEL WAVE IS MOVING EWD FROM NW SD/SE MT INTO
CENTRAL ND.  THE BAND OF CLOUDS OVER CENTRAL ND AND THE ELEVATED
THUNDERSTORMS IN NE ND APPEAR TO BE ASSOCIATED WITH THIS WAVE...AND
LOCAL VWP/S CONFIRM A PRONOUNCED VEERING OF LOW-LEVEL FLOW IN ND
WITH PASSAGE OF THIS WAVE.  THE 12Z BIS SOUNDING REVEALED VERY STEEP
MID LEVEL LAPSE RATES...BUT A STRONG CAP FOR SURFACE PARCELS AND
CONVECTIVE TEMPERATURES IN THE MID 90S.  THE CLOUDS...MODEST
MOISTURE...AND STRONG CAP ALL SUGGEST THAT SURFACE-BASED
THUNDERSTORM DEVELOPMENT WILL LIKELY BE CONFINED TO THE IMMEDIATE
COLD FRONT THIS AFTERNOON/EVENING ACROSS THE ERN DAKOTAS INTO WRN
MN.

MODIFYING THE 12Z BIS AND MODEL FORECAST SOUNDINGS FOR EXPECTED
AFTERNOON BOUNDARY LAYER CONDITIONS...MLCAPE VALUES RANGE FROM 1500
J/KG ACROSS NW MN TO 3000 J/KG INVOF SE SD WHERE RICHER MOISTURE
WILL SPREAD NWD ALONG THE MO RIVER VALLEY.  DEEP LAYER VERTICAL
SHEAR MAGNITUDE AND ORIENTATION WITH RESPECT TO THE FRONT APPEARS
SUPPORTIVE OF A BROKEN BAND OF SUPERCELLS AND/OR SHORT LINE SEGMENTS
THROUGH THE AFTERNOON/EVENING. VERY LARGE HAIL AND DAMAGING WINDS
ARE LIKELY WITH ANY SUPERCELLS IN THE LINE.  A COUPLE OF TORNADOES
WILL ALSO BE POSSIBLE THIS EVENING...WITH A LITTLE GREATER THREAT IN
MN WHERE LOW-LEVEL SHEAR/MOISTURE WILL BE SOMEWHAT GREATER THAN
AREAS FARTHER W.

...GULF AND SE ATLANTIC COASTS THIS AFTERNOON...
LOW-LEVEL DRYING HAS OCCURRED ACROSS THE SE ATLANTIC STATES COMPARED
TO YESTERDAY MORNING...AS THE MID LEVEL WAVE IN THE ELYS PROGRESSES
WWD OVER THE NE GULF AND FL PANHANDLE/SRN AL.  IT APPEARS THAT THE
GREATER INSTABILITY THIS AFTERNOON WILL BE FROM SRN MS INTO LA IN
ADVANCE OF THE MID LEVEL WAVE. THE NE MID LEVEL FLOW WILL FAVOR
MULTICELL CLUSTERS THAT MOVE INTO THE LOW-LEVEL HEAT/MOISTURE
AXIS...WHILE VERTICAL PROFILES FAVOR A FEW STORMS WITH WET
MICROBURSTS AND PERHAPS MARGINALLY SEVERE HAIL.

THOUGH DEEP LAYER FLOW IS WEAK OVER THE CAROLINAS...A SURFACE FRONT
WILL PROVIDE A FOCUS FOR THUNDERSTORM DEVELOPMENT THIS AFTERNOON. 
DEWPOINTS IN THE 70S AND AFTERNOON TEMPERATURES IN THE 90S WILL
SUPPORT MLCAPE VALUES OF 2000-3000 J/KG...ALONG WITH DCAPE VALUES IN
EXCESS OF 1000 J/KG.  THE STRONGER STORMS WILL BE CAPABLE OF
PRODUCING DAMAGING DOWNBURST WINDS.  ACROSS FL AND SE GA...SCATTERED
SEA BREEZE STORMS WILL OCCUR AGAIN THIS AFTERNOON...THOUGH THE
SEVERE STORM THREAT WILL BE LIMITED BY WARMING MID LEVEL
TEMPERATURES AND REDUCED INSTABILITY COMPARED TO YESTERDAY.

..THOMPSON/TAYLOR.. 08/05/2006