[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 190552
SWODY1
SPC AC 190551

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1251 AM CDT WED JUL 19 2006

VALID 191200Z - 201200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS CENTRAL AND SOUTHEASTERN
MN...CENTRAL AND SOUTHERN WI AND A SMALL PART OF NORTHEAST IA...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS ERN PARTS OF THE NRN
PLAINS EWD ACROSS THE UPPER MS VLY TO THE CNTRL GRTLKS...

...SYNOPSIS...
STRONGER WLYS WILL REMAIN ALONG THE NRN TIER OF THE COUNTRY ON WED
AS THE UPPER RIDGE AXIS CONTINUES ACROSS THE CNTRL PARTS OF THE
PLAINS AND ROCKIES.  A SHORTWAVE TROUGH...EMBEDDED WITHIN A WEAKER
SUBTROPICAL JET S OF THE PRIMARY WLYS OVER THE NRN ROCKIES...WILL
PROGRESS ESEWD REACHING THE UPPER MS VLY/UPPER GRTLKS BY THE END OF
THE PERIOD.

AT THE SFC...AN ASSOCIATED COLD FRONT WILL MOVE EWD ACROSS THE NRN
PLAINS AND UPPER MS VLY...REACHING A WRN LAKE SUPERIOR/SWRN MN/NRN
NEB LINE BY 20/00Z...AND CONTINUING TO ERN LAKE SUPERIOR/SWRN
WI/SWRN IA BY THE END OF THE PERIOD.  MEANWHILE...A WARM FRONT WILL
LIFT RAPIDLY NWD ACROSS THE UPPER MS VLY DURING THE MORNING WITH A
VERY MOIST WARM SECTOR DEVELOPING BY AFTN.

...UPPER MS VLY/CNTRL GRTLKS...
TUE EVENING UPPER AIR ANALYSIS SHOWS A STRONG WARM PLUME OF AIR
STREAMING EWD FROM THE CNTRL HIGH PLAINS TOWARD THE MO RVR VLY WITH
H7 TEMPERATURES IN EXCESS OF 16 DEG C AT KLBF. THIS ELEVATED MIXED
LAYER /EML/ WILL SPREAD INTO AT LEAST IA BY WED AFTN.  TO THE N OF
THIS CAP...CONSIDERABLE ELEVATED CONVECTION IS EXPECTED TO BE
ONGOING WED MORNING FROM THE DAKOTAS EWD INTO NWRN MN. STORMS MAY
ALREADY BE PRODUCING LARGE HAIL AT THAT TIME.  THIS ACTIVITY MAY
PERSIST/DEVELOP EWD ACROSS NRN MN AND INTO THE UPPER GRTLKS LATER IN
THE DAY WITH RISKS FOR DAMAGING WINDS AS WELL.

ATTENTION WILL THEN TURN TO A RATHER ACTIVE AFTN AND EVENING FROM
PARTS OF CNTRL/SRN MN INTO THE CNTRL GRTLKS.  BOUNDARY LAYER
MOISTURE IS EXPECTED TO RAPIDLY RETURN NWD BENEATH THE EML AND BY
AFTN UPPER 60S TO MID 70S F/MID-TEENS C SFC/H85 DEW POINTS WILL BE
COMMON ACROSS THE UPPER MS VLY.  STRONG HEATING WILL CONTRIBUTE TO A
VERY TO EXTREMELY UNSTABLE AIR MASS.  STRONGEST CAP WILL HOLD ACROSS
SWRN MN AND IA...BUT AS LARGE SCALE ASCENT ASSOCIATED WITH THE
TROUGH SPREADS EWD...THE CAP SHOULD WEAKEN ACROSS CNTRL/SRN MN BY
MID-AFTN.  AS A RESULT...TSTMS SHOULD DEVELOP ALONG/AHEAD OF THE
COLD FRONT AND EWD ALONG THE WARM FRONT MID-LATE AFTN FROM CNTRL MN
EWD INTO PARTS OF WI.

VERTICAL SHEAR PROFILES WILL BECOME STRONGER THROUGH THE LATE AFTN
AS A 50-70 KT H5 JET MOVES ACROSS THE REGION...BOOSTING 0-6KM VALUES
IN THE 60-70 KT RANGE. GIVEN THE MAGNITUDE OF LAPSE RATES...INITIAL
TSTMS WILL GROW INTO SUPERCELLS WITH VERY LARGE HAIL AND DAMAGING
WINDS. HODOGRAPHS BECOME QUITE LARGE VCNTY THE WARM FRONT FROM
CNTRL/SRN MN ACROSS SWRN WI AS A SWLY LLJ OF 40 KTS BECOMES
JUXTAPOSED WITH THE 70 KT WNWLY H5 JET DURING THE LATE AFTN.  LOW
LCLS AND STRONG LOW-LEVEL SHEAR WILL BE FAVORABLE FOR A FEW
TORNADOES WITH THE INITIAL SUPERCELLS...PRIMARILY ALONG THE WARM
FRONT.

EVOLUTION INTO A FORWARD PROPAGATING BOW ECHO/DERECHO APPEARS LIKELY
DURING THE EVENING AS THE LLJ VEERS WLY AND BECOMES ALIGNED WITH THE
WNWLY 70 KT H5 JET.  THIS WILL INCREASE THE DAMAGING WIND RISK INTO
WI AND POSSIBLY AS FAR E AND S AS PARTS OF LWR MI AND NRN IND/IL BY
12Z THU.  ADDITIONAL TSTMS WILL TEND TO BACKBUILD WWD INTO THE CAP
ACROSS IA DURING THE OVERNIGHT WITH AN ATTENDANT RISK OF LARGE HAIL.


...CNTRL-SRN APPALACHIANS...
WEAK BOUNDARIES WILL BE PRESENT ACROSS PARTS OF THE CNTRL-SRN
APPALACHIANS WED.  STRONG HEATING...AMPLE BOUNDARY LAYER MOISTURE
AND WEAK UPSLOPE COMPONENT WILL CONTRIBUTE TO TSTMS DEVELOPING
ESPECIALLY ALONG THE ERN SLOPES OF THE MOUNTAINS.  MULTICELL STORM
CLUSTERS MAY APPROACH/BRIEFLY EXCEED SEVERE LIMITS WITH DAMAGING
WINDS THE PRIMARY THREAT THREAT.

...GULF COASTAL STATES...
DIURNAL TSTMS...ENHANCED BY LOCAL CONVERGENCE FROM OUTFLOW
BOUNDARIES/SEA BREEZE...WILL BE LIKELY ACROSS MOST OF THE GULF
COASTAL REGION WED AFTN.  THETA-E PROFILES WILL DECREASE RAPIDLY
WITH HEIGHT AND SUGGESTS THAT ISOLD MICROBURSTS MAY ACCOMPANY THE
PULSE MULTICELL STORM CLUSTERS.

...SWRN DESERTS...
00Z WED H5 CHART SUGGESTS THAT THE MID-TROPOSPHERE SHOULD WARM A
DEGREE OR TWO OVER TUE READINGS ACROSS THE SWRN DESERTS. 
BUT...BOUNDARY LAYER MOISTURE MAY BE HIGHER THAN PREVIOUS DAYS OWING
TO RECENT SLOW MOVING TSTMS.  AS A RESULT...ANY TSTM THAT CAN MANAGE
TO FORM MAY PRODUCE ISOLD DAMAGING WIND GUSTS. CONVECTIVE COVERAGE
WILL BE HIGHLY MODULATED BY THE MAGNITUDE OF CLOUD DEBRIS THAT
REMAINS OVER THE REGION FROM TUE EVE/OVERNIGHT TSTMS.

..RACY/TAYLOR.. 07/19/2006