Hail and Damaging Winds in Iowa, March 12 to 13, 2006

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
1252 PM CST SUN MAR 12 2006

.SHORT TERM /THIS AFTERNOON INTO THIS EVENING/...
POTENTIAL SVR WX OUTBREAK SETTING UP ACROSS CENT/SRN CWA THIS AFT
INTO THIS EVE. LATEST 18Z MSAS SFC ANALYSIS SHOWS 999MB LOW OVER
WCENT KN WITH WARM BOUNDARY EXTNDG EWD INTO NCENT MO...WHERE WELL
DEFINED BAROCLINIC ZONE HAS SET UP.

850-700MB THETA-E ADV MAXED OUT ON THE NOSE OF 40+KT LLJ POINTING
INTO SRN IA...INITIATING CURRENT ELEVATED CONVECTION ACROSS SRN
CWA. AS WARM FRONT CONTS TO ADVANCE NWD THIS AFT...LOOK FOR LLVL
WAA TO SCOUR OUT SHALLOW STABILITY ALLOWING FOR STORMS TO
POTENTIALLY BECOME SFC BASED. DEEP (0-6KM) AND LLVL (0-1KM) SHEAR
PROFILES MORE THAN FAVORABLE FOR SUPER CELLS WITH ROTATION...WITH 0-3KM
SRH VALUES OFF THE CHART. LARGE HAIL FROM ELEVATED SUPERCELLS
APPEARS LIKELY...WITH TOR THREAT INC IF STORMS CAN BECOME ROOTED
NEAR SFC.

MADE QUICK UPDATES TO THE GRIDS. UPDATED ZFP OUT SHORTLY.

&&

.PREV DISCUSSION... (ISSUED 913 AM CST SUN MAR 12 2006)

SHORT TERM /THIS AFTERNOON/...
UPDATE TO TEXT FORECAST TO INCREASE AREAL COVERAGE OF POPS WITH
INITIAL AREA OF SHRA/EMBEDDED TSRA. ALSO TIGHTENED UP CURRENT
GRIDDED DATABASE BASED ON HOURLY TRENDS.

PREV DISCUSSION... (ISSUED 400 AM CST SUN MAR 12 2006)

DISCUSSION...

.SIGNIFICANT SEVERE WEATHER EXPECTED THIS AFTERNOON INTO THIS
EVENING ACROSS PORTIONS OF THE CWA...

THE NEXT 24 HOURS WILL BE EXTREMELY BUSY AS POTENT SOUTHWEST STORM
EJECTS INTO THE REGION.  CURRENTLY...SFC RIDGE SLIDING ACRS S MN
WITH DRY NORTHERLY FLOW ACRS IA.  HOWEVER...FRONTAL BOUNDARY WHICH
SLID THROUGH ON SATURDAY HAS STALLED IN OK AND S MO IN RESPONSE TO
LEE SIDE CYCLOGENESIS.  THIS BOUNDARY WL QUICKLY PUSH BACK NORTH
TODAY AS THE LOW DEEPENS AND HEADS TO THE EAST THIS AFTERNOON. GFS
AND NAM STILL DIFFER ON NORTHWARD LIMIT OF MOVEMENT WHICH HAS VERY
LARGE IMPLICATIONS ON TORNADO THREAT ACRS THE CWA.  SHEAR IS PEGGED
WITH 0-6KM BULK SHEAR FROM 75-100KTS...BRN SHEAR OVER 200 AND 0-1KM
HELICITY IN EXCESS OF 200.  SO...LIMITING FACTOR (FOR TORNADOES
ANYWAY) WL BE THE AVAILABILITY OF LOW LEVEL CAPE WHICH ENDS UP BEING
A FUNCTION OF FRONTAL POSITIONING. GFS HAS REMAINED RATHER
CONSISTENT IN ITS LOCATIONS AND SPC GUIDANCE CERTAINLY FAVORS THIS
SOLUTION AS WELL.  I CERTAINLY DON/T WANT TO UNDERESTIMATE ITS
NORTHWARD MOVEMENT AND A LIBERAL INTERPRETATION IS PROBABLY BEST
COURSE OF ACTION.  THIS PUTS ANY LOCATION ALONG AND SOUTH OF THE
WARM FRONT IN HIGH RISK FOR ALL TYPES OF SEVERE CONVECTION AND WL
PUT THIS LINE FROM NEAR CRESTON THROUGH KDSM TO TAMA.  SEVERE
WEATHER REMAINS POSSIBLE NORTH OF THIS LINE AS WELL WITH ELEVATED
STORMS PRODUCING LARGE HAIL. STORMS WL ALSO HAVE VERY FAST MOVEMENT
WITH BUNKERS MOTION IN EXCESS OF 50KTS TO THE NORTHEAST.   FARTHER
NORTHWEST...PCPN TYPE AND QUANTITY BECOME A CONCERN WITH REGARDS TO
SNOWFALL AMOUNTS.  EST SOUNDING IS PRETTY MUCH SNOW FOR ENTIRE EVENT
WITH CHANGE OVER IN FROM NORTHWOOD TO POCAHONTAS IN THE EVENING.
APPEARS WE WL PUSH WARNING CRITERIA NEAR EST BUT OTHER LOCATIONS
SHOULD BE LESS AS WARMER SOUNDING HOLD OFF CHANGEOVER UNTIL A
SIGNIFICANT PORTION OF THE PCPN HAS FALLEN.  HAVE OPTED FOR AN
ADVISORY ACRS THE NORTH TONIGHT NORTH OF A POCAHONTAS TO NORTHWOOD
LINE WHERE 3-6 INCHES ARE EXPECTED. SOME RESIDUAL LIGHT SNOW ON
MONDAY WITH MUCH COOLER TEMPERATURES AS SYSTEM PULLS TO THE
NORTHEAST.  OTHERWISE...SYSTEM ON WEDNESDAY INTO EARLY THURSDAY
STILL APPEARS TO BE PROBLEMATIC.  GFS/EURO AND CANADIAN ALL
ADVERTISE RA/SN ACRS THE CWA...GOING FORECAST HAS THIS COVERED.
SNOW AMOUNTS COULD GET RATHER HIGH IF FORECAST TRACK REMAINS
RELATIVELY CONSISTENT.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
SNOW ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST MONDAY FOR
EMMET-HANCOCK-KOSSUTH-PALO ALTO-POCAHONTAS-WINNEBAGO-WORTH.

&&

.SHORT TERM...STEINBUGL

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
920 AM CST SUN MAR 12 2006

IAZ075-084>086-093>097-131200-
MAHASKA-LUCAS-MONROE-WAPELLO-RINGGOLD-DECATUR-WAYNE-APPANOOSE-
DAVIS-
920 AM CST SUN MAR 12 2006

...SIGNIFICANT SEVERE WEATHER OUTBREAK EXPECTED THIS AFTERNOON AND
EVENING ACROSS PORTIONS OF CENTRAL AND SOUTHERN IOWA...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTH CENTRAL
IOWA...MAINLY ALONG AND SOUTH OF HIGHWAY 34.

.DAY ONE...TODAY AND TONIGHT

AN ISOLATED SEVERE STORM IS POSSIBLE THIS MORNING...WITH THE MAIN
THREAT OF HAIL UP TO QUARTER SIZE. MORE WIDESPREAD SEVERE WEATHER IS
EXPECTED THIS AFTERNOON AND EVENING ACROSS THE OUTLOOK AREA. LARGE
HAIL UP TO BASEBALL SIZE...DAMAGING WINDS IN EXCESS OF 60 MPH AND
DAMAGING TORNADOES ARE ALL POSSIBLE. ALTHOUGH SEVERE WEATHER MAY
DEVELOP BY EARLY AFTERNOON...THE TIME OF GREATEST THREAT APPEARS TO
BE FROM 4 PM TO 9 PM. STORM MOVEMENT WILL BE VERY RAPID TO THE
NORTHEAST AT 40 TO 60 MPH.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

ANOTHER STORM IS EXPECTED TO AFFECT THE AREA LATER WEDNESDAY INTO
EARLY THURSDAY. THE POTENTIAL FOR SEVERAL INCHES OF SNOW EXISTS
WITH THIS SYSTEM.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL BE NECESSARY MAINLY THIS AFTERNOON AND
EVENING. A PROACTIVE APPROACH TO DEPLOYING SPOTTERS WILL BE NEEDED
AS THESE STORMS WILL BE MOVING VERY QUICKLY. WAITING FOR A WARNING
MAY RESULT IN SPOTTERS MISSING THE STORM DUE TO THE FAST MOVEMENT.

A CONFERENCE CALL FOR EMERGENCY MANAGEMENT COORDINATORS WILL BE
CONDUCTED AT 10 AM THIS MORNING.

IAZ048>050-057>062-070>074-081>083-092-131200-
STORY-MARSHALL-TAMA-AUDUBON-GUTHRIE-DALLAS-POLK-JASPER-POWESHIEK-
CASS-ADAIR-MADISON-WARREN-MARION-ADAMS-UNION-CLARKE-TAYLOR-
920 AM CST SUN MAR 12 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL
IOWA...MAINLY NORTH OF HIGHWAY 34 AND SOUTH OF HIGHWAY 30.

.DAY ONE...TODAY AND TONIGHT

AN ISOLATED SEVERE STORM IS POSSIBLE THIS MORNING ALONG AND SOUTH OF
THE INTERSTATE 80 CORRIDOR...WITH THE MAIN THREAT OF HAIL UP TO
QUARTER SIZE. MORE WIDESPREAD THUNDERSTORMS ARE EXPECTED BY THIS
AFTERNOON AND CONTINUING INTO THE EVENING. SOME OF THESE STORMS WILL
BE SEVERE WITH THE MAIN THREAT FROM LARGE HAIL UP TO BASEBALL SIZE.
DAMAGING WINDS AND AN ISOLATED TORNADO ARE ALSO POSSIBLE. A WARM
FRONT ENTERING FAR SOUTH IOWA WILL BE THE FOCUS FOR THE
THUNDERSTORMS AND IF THIS FRONT ENDS UP FARTHER NORTH...THE THREAT
FOR WIND AND TORNADOES MAY INCREASE. THE SEVERE WEATHER THREAT WILL
LIKELY BEGIN BY EARLY AFTERNOON WITH THE GREATEST THREAT FROM 4 PM
TO 9PM. STORM MOVEMENT WILL BE VERY FAST TO THE NORTHEAST AT 40 TO
60 MPH.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

ANOTHER STORM IS EXPECTED TO AFFECT THE AREA LATER WEDNESDAY INTO
EARLY THURSDAY. THE POTENTIAL FOR SEVERAL INCHES OF SNOW EXISTS
WITH THIS SYSTEM.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS EXPECTED MAINLY THIS AFTERNOON AND EVENING. A
PROACTIVE APPROACH TO DEPLOYING SPOTTERS WILL BE NEEDED AS THESE
STORMS WILL BE MOVING VERY QUICKLY. WAITING FOR A WARNING MAY RESULT
IN SPOTTERS MISSING THE STORM DUE TO THE FAST MOVEMENT.

A CONFERENCE CALL FOR EMERGENCY MANAGEMENT COORDINATORS WILL BE
CONDUCTED AT 10 AM THIS MORNING.

IAZ017-024>028-033>039-044>047-131200-
CERRO GORDO-HUMBOLDT-WRIGHT-FRANKLIN-BUTLER-BREMER-SAC-CALHOUN-
WEBSTER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK-CRAWFORD-CARROLL-GREENE-
BOONE-
920 AM CST SUN MAR 12 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA
NORTH OF HIGHWAY 30 AND SOUTH OF HIGHWAY 3.

.DAY ONE...TODAY AND TONIGHT

ISOLATED TO SCATTERED THUNDERSTORMS ARE EXPECTED THIS AFTERNOON
INTO THIS EVENING. SOME LARGE HAIL IS POSSIBLE WITH THESE STORMS
AS THEY RACE NORTHEAST AT 40 TO 60 MPH. ANY RAIN WILL CHANGE TO
SNOW TONIGHT WITH SOME LIGHT ACCUMULATIONS POSSIBLE BY MONDAY
MORNING.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

ANOTHER STORM IS EXPECTED TO AFFECT THE AREA LATER WEDNESDAY INTO
EARLY THURSDAY. THE POTENTIAL FOR SEVERAL INCHES OF SNOW EXISTS
WITH THIS SYSTEM.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EARLY EVENING.

A CONFERENCE CALL FOR EMERGENCY MANAGEMENT COORDINATORS WILL BE
CONDUCTED AT 10 AM THIS MORNING.

IAZ004>007-015-016-023-131200-
EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-POCAHONTAS-
920 AM CST SUN MAR 12 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA.

.DAY ONE...TODAY AND TONIGHT

RAIN AND SNOW IS EXPECTED TO DEVELOP BY THIS AFTERNOON CHANGING TO
ALL SNOW THIS EVENING. THE SNOW WILL CONTINUE OVERNIGHT BEFORE
TAPERING TO FLURRIES MONDAY MORNING. SNOWFALL OF 3 TO 6 INCHES
WITH ISOLATED HIGH AMOUNTS ARE POSSIBLE. IN ADDITION...WINDS WILL
INCREASE FROM THE NORTH OVERNIGHT PRODUCING SOME BLOWING AND
DRIFTING SNOW.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

ANOTHER STORM IS EXPECTED TO AFFECT THE AREA LATER WEDNESDAY INTO
EARLY THURSDAY. THE POTENTIAL FOR SEVERAL INCHES OF SNOW EXISTS
WITH THIS SYSTEM.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED. HOWEVER...REPORTS OF SNOW
AMOUNTS WOULD BE APPRECIATED.

A CONFERENCE CALL FOR EMERGENCY MANAGEMENT COORDINATORS WILL BE
CONDUCTED AT 10 AM THIS MORNING.

COGIL/KINNEY