Severe Thunderstorm Warning 36, NWS Des Moines, IA

000 
WWUS53 KDMX 020314
SVSDMX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
1014 PM CDT THU MAY 1 2008

IAC157-020324-
/O.CAN.KDMX.SV.W.0036.000000T0000Z-080502T0330Z/
POWESHIEK IA-
1014 PM CDT THU MAY 1 2008

...THE SEVERE THUNDERSTORM WARNING FOR POWESHIEK COUNTY IS
CANCELLED...

AT 1009 PM CDT...WEATHER SERVICE DOPPLER RADAR INDICATED THAT THE 
THUNDERSTORMS WHICH PROMPTED THE WARNING HAVE WEAKENED...AND NO 
LONGER POSE AN IMMEDIATE THREAT TO LIFE OR PROPERTY. THEREFORE...THE 
SEVERE THUNDERSTORM WARNING HAS BEEN CANCELLED.

HOWERVER...A TORNADO WATCH REMAINS IN EFFECT UNTIL 100 AM CDT FRIDAY 
MORNING FOR SOUTHERN IOWA.

LAT...LON 4164 9274 4187 9249 4186 9230 4186 9229
      4178 9229 4177 9228 4172 9229 4152 9256
TIME...MOT...LOC 0314Z 221DEG 27KT 4174 9245

$$

LEE

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
645 PM CDT THU MAY 1 2008

UPDATED AVIATION DISCUSSION

.SHORT TERM...TONIGHT
SURFACE LOW OVER EASTERN NEBRASKA AT 20Z WITH DRY LING PUSHING
ACROSS THE MO RIVER ALONG THE WESTERN IA BORDER.  PREFER GFS AND RUC
SOLN THIS EVENING WITH DRY LINE MOVING INTO THE WESTERN FA AND
SURFACE LOW REMAINING NW OF IA.  DRY LINE SHOULD STALL AS IT REACHES
CENTRAL IA SINCE UPPER LEVEL SUPPORT IS HANGING BACK TO THE WEST.
NARROW AXIS OF CAPES AND CNVG EAST OF DRY LINE WITH INCREASING DEEP
SHEAR AND GOOD LOW-LVL SHEAR.  TSTM CHANCES INHIBITED BY STRONG MID
LVL CAP. SHOULD CAP BREAK...EXPECT PSBL SVR WX IN WRN AND NW CWA
THIS EVENING FM SCT TO ISOLD STORMS.  MCS MAY MOVE INTO SRN IA AFTER
06Z AND WILL FORECAST HIGHER POPS THEN.  SEVERE CHANCES WILL BE LESS
HOWEVER.

.LONG TERM...FRIDAY THROUGH WEDNESDAY
SURFACE LOW EXPECTED TO MOVE NE THROUGH IA ON FRIDAY AS A VIGOROUS
TROUGH ROTATES AROUND SE SIDE OF UPPER LOW. THIS SHOULD MAKE FOR
RAPIDLY CHANGING WEATHER AS REMAINS OF OVERNIGHT CONVECTION LIFTS
NEWD THROUGH EASTERN PORTIONS OF IA. REDEVELOPMENT OF SECOND ROUND
OF CONVECTION IS EXPECTED AROUND MIDDAY...ESPECIALLY N AND E. THERE
WOULD BE SOME THREAT OF SEVERE WEATHER EAST OF MARSHALLTOWN-GRINNELL
WITH FAVORABLE CONDITIONS FOR LOW-TOPPED ROTATING STORMS BUT
RESIDENCE TIME IN OUR FORECAST AREA WILL BE SHORT. FRIDAY NIGHT AND
SATURDAY...UPPER LOW AND COLD POOL MOVE ACROSS IA. RAIN IN
DEFORMATION ZONE WILL BE MOST PROLONGED NW OF FORT DODGE...AND
FORECAST TEMPERATURE PROFILES EVEN INDICATE A MIX OF RAIN AND SNOW
IS POSSIBLE LATE FRIDAY NIGHT EARLY SATURDAY. THIS WILL HOLD
TEMPERATURES DOWN AROUND OR BELOW 50 DEGREES THROUGH SATURDAY.

RAINFALL COLD BE SUFFICIENT IN THE EAST AND NORTH TO BRING RIVERS
BACK UP TOWARD FLOOD STAGE. HOWEVER...AT THIS TIME MOISTURE DOES NOT
LOOK NEARLY AS DEEP AS PREVIOUS SYSTEM AND STORM LOOK TO BE
PROGRESSIVE. THUS...TOTAL RAINFALL SHOULD BE LESS THAN ONE INCH IN
GENERAL AND AS SUCH FLASH FLOODING WOULD BE LESS OF A CONCERN.

SUNDAY AND MONDAY LOOK TO BE NICE WITH A SLOW MODERATION IN
TEMPERATURES. AFTER THAT...GFS MODEL WOULD LIKE TO BRING IN WARM
ADVECTION AND A CHANCE FOR PRECIPITATION AS EARLY AS MONDAY
NIGHT...AND HAVE IT EXIT ALREADY ON WEDENSDAY. THIS IS QUITE A BIT
FASTER THAN PREVIOUS RUNS...AND ECMWF IS SLOWER AND FARTHER TO THE
SOUTH WITH ITS FORCING FOR PRECIPITATION.  RESULT IN FORECAST IS A
CHANCE OF SHOWERS AND THUNDER CENTERED ON WEDNESDAY...WITH BEGIN AND
END TIME SPREAD OUT INTO ADJOINING DAYS AND EXACT TIMING TO BE
DETERMINED.

&&

.AVIATION...02/00Z
NEAR TERM FORECAST IS STILL UNCERTAIN WITH TS POTENTIAL...SO WILL
ONLY CARRY CB MENTIONS FOR POTENTIAL TS DEVELOPMENT NEAR KFOD AND
KDSM EARLY IN THE PERIOD. LOWEST CEILINGS...COMING DOWN TO IFR WILL
OCCUR NORTH OF WARM FRONT LATER TONIGHT...AND WRAP AROUND SHRA/TS
WILL MOVE IN FROM THE NW. DRY SLOT FARTHER SOUTH WILL KEEP VFR
CONDITIONS GOING LATER TONIGHT UNTIL WRAP AROUND LOWER CEILINGS MOVE
IN. THREAT FOR TS WILL BE AROUND AFT 12Z FROM KMCW TO KOTM.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE

&&

SHORT TERM...JOHNSON
LONG TERM...JUNGBLUTH
AVIATION...MOYER

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
600 PM CDT THU MAY 1 2008

IAZ006-007-016-017-025>028-036>039-097-022300-
WINNEBAGO-WORTH-HANCOCK-CERRO GORDO-WRIGHT-FRANKLIN-BUTLER-BREMER-
HAMILTON-HARDIN-GRUNDY-BLACK HAWK-DAVIS-
600 PM CDT THU MAY 1 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA.

.DAY ONE...TONIGHT

SCATTERED THUNDERSTORMS ARE EXPECTED TONIGHT...MAINLY AFTER
MIDNIGHT. ISOLATED SEVERE WEATHER IS POSSIBLE...WITH LARGE HAIL
AND STRAIGHT LINE WINDS THE MAIN THREATS. ISOLATED FLASH FLOODING
CANNOT BE RULED OUT...IF HEAVY RAIN DEVELOPS ACROSS AREAS WHERE
THE GROUND IS SATURATED FROM RECENT HEAVY RAIN.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

SHOWERS AND THUNDERSTORMS WILL CONTINUE FRIDAY...ESPECIALLY DURING
THE DAY TIME HOURS. TOTAL RAINFALL AMOUNTS OF 1 TO 2 INCHES ARE
POSSIBLE THROUGH FRIDAY NIGHT.  RENEWED RIVER FLOODING COULD ALSO
OCCUR INTO NEXT WEEK IN RESPONSE TO THE HEAVY RAINFALL. ISOLATED
SEVERE STORMS ARE POSSIBLE...MAINLY ALONG AND EAST OF INTERSTATE
35. IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...AN ISOLATED
TORNADO WILL BE POSSIBLE.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED LATE TONIGHT...AND AGAIN ON
FRIDAY FROM LATE MORNING THROUGH THE AFTERNOON HOURS.

IAZ004-005-015-023-024-033>035-044>050-057>062-070>075-081>086-
092>096-022300-
EMMET-KOSSUTH-PALO ALTO-POCAHONTAS-HUMBOLDT-SAC-CALHOUN-WEBSTER-
CRAWFORD-CARROLL-GREENE-BOONE-STORY-MARSHALL-TAMA-AUDUBON-GUTHRIE-
DALLAS-POLK-JASPER-POWESHIEK-CASS-ADAIR-MADISON-WARREN-MARION-
MAHASKA-ADAMS-UNION-CLARKE-LUCAS-MONROE-WAPELLO-TAYLOR-RINGGOLD-
DECATUR-WAYNE-APPANOOSE-
600 PM CDT THU MAY 1 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA.

.DAY ONE...TONIGHT

THERE IS A SLIGHT CHANCE OF SEVERE THUNDERSTORMS OVER WESTERN AND
CENTRAL IOWA THIS EVENING. IF THE THUNDERSTORMS DEVELOP...THEY
WILL BE CAPABLE OF PRODUCING DAMAGING WINDS...LARGE HAIL AND EVEN
ISOLATED TORNADOES. THE BEST CHANCE WILL BE UNTIL MIDNIGHT.

SCATTERED THUNDERSTORMS ARE EXPECTED LATE TONIGHT. ISOLATED SEVERE
WEATHER IS POSSIBLE...WITH LARGE HAIL AND STRAIGHT LINE WINDS THE
MAIN THREATS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

SHOWERS AND THUNDERSTORMS WILL CONTINUE FRIDAY...ESPECIALLY DURING
THE DAY TIME HOURS. TOTAL RAINFALL AMOUNTS OF AN INCH OR LESS ARE
POSSIBLE THROUGH FRIDAY NIGHT. SEVERE WEATHER IS UNLIKELY ON FRIDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS EVENING AND LATE TONIGHT...AND
AGAIN ON FRIDAY FROM LATE MORNING THROUGH THE AFTERNOON HOURS.

MOYER