[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 131640
SWODY1
SPC AC 131638

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1138 AM CDT THU JUL 13 2006

VALID 131630Z - 141200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF THE LWR MO VLY...

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE ERN DAKS/WRN MN SWD
INTO OK AND MO...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE MID ATLANTIC
STATES AND SOUTHEAST...

...SYNOPSIS...
AN ACTIVE STORM PERIOD EXPECTED OVER THE CNTRL PLNS/LWR MO VLY AS
WRN RIDGE REBOUNDS IN WAKE OF PROGRESSIVE SHORTWAVE TROUGH NOW
ENTERING THE DAKOTAS.  THE TROUGH LIKELY WILL SPLIT...WITH MAIN
PORTION CONTINUING E TO THE UPR MS VALLEY BY LATE TONIGHT AS SRN
PART DROPS SE ON NERN FRINGE OF RIDGE.

...CNTRL PLNS/LWR MO VLY...
A VERY MOIST...VERY WARM BOUNDARY LAYER AIR MASS IS IN PLACE FROM
THE CNTRL PLNS/LWR MO VLY NWD IN A NARROWING AXIS TO THE ERN
DAKOTAS/WRN MN.  STRONG HEATING WILL CONTINUE THROUGH THE AFTERNOON
ALONG AND AHEAD OF WEAK COLD FRONT MOVING E/SE ACROSS THE DAKOTAS
AND WRN NEB.  SUBSTANTIAL HEATING WILL ALSO OCCUR ALONG STATIONARY
FRONT EXTENDING ESE FROM ERN NEB INTO CNTRL/SRN IL.  STEEPENING LOW
LEVEL LAPSE RATES AND QUALITY MOISTURE SUPPLY SHOULD BOOST AFTERNOON
SBCAPE TO AOA 4000 J/KG ACROSS A BROAD SWATH FROM CNTRL NEB ESE INTO
PARTS OF KS/IA AND NRN MO.

DEEP SHEAR ACROSS MDT AND SLGT RISK AREAS WILL INTENSIFY TODAY
THROUGH TONIGHT AS MID LEVEL FLOW VEERS AND STRENGTHENS ON SW SIDE
OF SHORTWAVE IMPULSE.  BY MID TO LATE AFTERNOON...30-40 KT DEEP NWLY
SHEAR SHOULD EXTEND FROM SE SD SEWD INTO NRN KS/NW MO. WITH
TIME...STRONGER NW FLOW ALOFT SHOULD ALSO SPREAD S TOWARD THE SRN
PLNS.

OVERALL KINEMATIC/THERMODYNAMIC SETUP SUGGESTS THAT CONTINUED
SURFACE HEATING WILL ALLOW SLIGHTLY ELEVATED STORMS NOW OVER NEB AND
THE ERN DAKOTAS TO BECOME SURFACE-BASED A BIT LATER THIS AFTERNOON. 
OTHER STORMS LIKELY WILL FORM INVOF AFOREMENTIONED SURFACE
BOUNDARIES NWD INTO THE ERN DAKOTAS.  GIVEN DEGREE OF INSTABILITY
AND STRENGTHENING SHEAR...CONDITIONS WILL BE FAVORABLE FOR SUSTAINED
STORMS AND A FEW SUPERCELLS WITH VERY LARGE HAIL AND DAMAGING WET
MICROBURSTS...ESPECIALLY IN NEB AND THE LWR MO VLY.  THESE STORMS
SHOULD FAIRLY QUICKLY MERGE INTO ONE OR TWO LARGE CLUSTERS...WITH
FORWARD PROPAGATING SEGMENTS EXTENDING A THREAT FOR WIND/HAIL E/SE
INTO PARTS OF KS/MO AND PERHAPS SRN IA BY EARLY THIS EVENING. 
ISOLATED HIGH WIND-PRODUCING STORMS MAY ALSO FORM INVOF LEE TROUGH
IN NW KS...AND ALONG FRONT IN SRN IA.  LATER TONIGHT AND EARLY
FRIDAY...FORWARD-PROPAGATING CONVECTIVE SEGMENTS MAY EXTEND A THREAT
FOR HIGH WIND SWD INTO NRN OK.

...MID ATLANTIC STATES...
E/W COLD FRONT ACROSS PA WILL CONTINUE SLOWLY SWD...PRECEEDED BY A
DEEP...WARM AND MOIST WLY FLOW INTO VA/NC.  DIFFERENTIAL HEATING
OCCURRING ALONG PREFRONTAL LINE OF CONVECTIVE DEBRIS...AND
OROGRAPHIC INFLUENCE...LIKELY WILL INITIATE STORMS OVER SW VA/ERN TN
AND NW NC A BIT LATER THIS AFTERNOON.  MLCAPE WILL BE AOA 2000
J/KG...BUT RELATIVELY WEAK LAPSE RATES SHOULD LIMIT INTENSITY OF
CONVECTIVE DEVELOPMENT.  20-25KT OF DEEP UNIDIRECTIONAL
SHEAR SHOULD SUPPORT MULTICELL LINE SEGMENTS WITH THE POTENTIAL FOR
SCATTERED WET MICROBURSTS.

...LWR TN VLY...
VERY MOIST AND UNSTABLE AIR WILL PREVAIL S OF STATIONARY FRONTAL
ZONE FROM THE MID MS VALLEY E TO APPALACHIANS. WEAK SHEAR
WILL BE CONDUCIVE TO PRIMARILY A PULSE SEVERE THREAT. THUS WHILE
THERE IS THE POTENTIAL FOR DAMAGING DOWNBURSTS AND LARGE HAIL OVER
MUCH OF THIS AREA...COVERAGE SHOULD BE LIMITED.

..CORFIDI/GUYER.. 07/13/2006