Severe Thunderstorm Warning 121, NWS Des Moines, IA

000 
WWUS53 KDMX 291811
SVSDMX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
110 PM CDT TUE MAY 29 2007

IAC169-291820-
/O.CAN.KDMX.SV.W.0121.000000T0000Z-070529T1830Z/
STORY IA-
110 PM CDT TUE MAY 29 2007

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN STORY COUNTY IS
CANCELLED...

THE THUNDERSTORM HAS WEAKENED THEREFORE THE WARNING HAS BEEN 
CANCELLED.  ONE HALF INCH HAIL 6 MILES SOUTH OF MCCALLSBURG HAS BEEN 
REPORTED WITH THIS STORM.

LAT...LON 4220 9352 4220 9324 4197 9324 4199 9355

$$

DONAVON

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
633 AM CDT TUE MAY 29 2007

UPDATED AVIATION DISCUSSION

.SYNOPSIS...
SOUTH FLOW WILL CONTINUE TO BRING INCREASING MOISTURE BEFORE A SLOW
MOVING COLD FRONT FINALLY MOVES THROUGH IOWA WEDNESDAY AND WEDNESDAY
NIGHT. THE MAIN PRECIPITATION EVENT FOR CENTRAL IOWA IS EXPECTED TO
BE ON WEDNESDAY AND WEDNESDAY NIGHT. THE UPPER LOW ASSOCIATED WITH
THIS SYSTEM WILL BE EVEN SLOWER TO MOVE EAST THAN THE FRONT...WITH
THE UPPER LOW REMAINING STALLED OVER THE DAKOTAS FROM TUESDAY
THROUGH FRIDAY. A SHORT-LIVED BREAK IN THE WEATHER IS EXPECTED ON
THURSDAY BEFORE SHOWER AND THUNDERSTORM CHANCES INCREASE AGAIN ON
FRIDAY.

&&

.SHORT TERM /TODAY/...
SFC LOW OVR ERN ND EARLY THIS MORNING WITH COLD FRONT TRAILING SOUTH
THROUGH CENTRAL SD AND BACK TO A SECONDARY LOW IN NE CO. AIRMASS
AHEAD OF COLD FRONT IS MILD WITH DWPTS IN THE LOWER TO MID 60S.
WHILE A STRAY SHOWER CANNOT BE RULED OUT EARLY THIS MORNING...MOST
CONVECTIVE ACTIVITY WILL REMAIN WEST OF OUR AREA. AS ENTIRE SYSTEM
ACROSS THE PLAINS SHIFTS EAST TODAY AND DIURNAL DESTABILIZATION
OCCURS...THE CHANCE OF SHOWERS OR TSTMS INCREASES SOMEWHAT. MODELS
IN GOOD AGREEMENT WITH BRINGING COLD FRONT INTO SE SD BY EVENING. NO
REAL DEFINITIVE SURFACE BOUNDARIES AHEAD OF THE FRONT ACROSS CENTRAL
IOWA TODAY...BUT MINOR SHORTWAVES RIDING NORTHEAST IN THE SOUTHWEST
FLOW ALOFT AND A MINOR UPR LVL JET STREAK APPROACHING CENT IA THIS
AFTN MAY BE ENOUGH TO GENERATE SCATTERED SHOWERS AND TSTMS...WITH
HIGHEST PROBABILITIES NW SECTIONS...CLOSER TO APPROACHING FRONT. MID
LVL LAPSE RATES OF NOT QUITE 6 DEGREES C/KM AND MIXED LAYER CAPES
LESS THAN 1000 J/KG SUGGEST THAT ANY TSTMS THAT DO DEVELOP WILL BE
GARDEN VARIETY.

.LONGER TERM...
THUNDERSTORMS IN THIS MOIST SOUTH FLOW HAVE MOSTLY BEEN OCCURRING
DURING THE DAYLIGHT HOURS...BUT THERE COULD BE A LINGERING SHOWER
ESPECIALLY IN THE WESTERN FORECAST AREA THIS EVENING. AFTER THAT...
SHORT WAVE OVER ERN TX AND OK WILL LIFT NWD EARLY ON WEDNESDAY AHEAD
OF THE NORTHERN ROCKIES SYSTEM. THIS COULD MUDDY THE WATERS DURING
THE DAY ON WEDNESDAY AS WEAK FORCING FOR LIFT AND DEEP MOISTURE ARE
LIKELY TO PRODUCE A LOT OF CLOUDS AND A FEW SHOWERS OUT AHEAD OF THE
ADVANCING COLD FRONT. THUS WENT FOR LIKELY POPS ALL DAY WEDNESDAY
EVEN THOUGH INSTABILITY AND CONVERGENCE WILL MOST LIKELY HOLD OFF
UNTIL LATER IN THE DAY AS THE FRONT APPROACHES. HEAVY RAIN IS LIEKLY
TO BE THE BIGGER THREAT FROM WEDNESDAY AFTERNOON INTO THE EARLY
HOURS OF THURSDAY MORNING DUE TO DEEP MOISTURE...MODERATE
INSTABILITY AND WEAK SHEAR. WEAK SHEAR IS IN SPITE OF STRONG LOW
LEVEL JET AROUND 40 KT WHICH WILL PRODUCE SHORT CORFIDI VECTORS AND
THE POSSIBILITY OF SLOW MOVING OR TRAINING STORMS. THIS LOOKS MOST
LIKELY TO LINE UP IN WEST CENTRAL INTO CENTRAL IA WED EVENING...THE
AREA THAT HAS SEEN RECENT HEAVY RAINS AND SATURATION. SO...WILL
UPDATE ESF LATER THIS MORNING.  RAINFALL IN EXCESS OF 2 INCHES IS
NOT OUT OF THE QUESTION ALTHOUGH CURRENTLY QPF GRIDS ARE CARRYING
AROUND 1.25 INCHES.

AFTER THAT...FRONT IS LIKELY TO CLEAR EAST OF DMX FORECAST AREA BY
EARLY THU MORNING...BUT THERE IS SOME MODEL DISAGREEMENT AND
UNCERTAINTY EXACTLY WHERE IT WILL STALL AND HOW IT WILL PROGRESS
BACK NWD. AT THIS TIME...ALL MODELS FAVOR A BREAK IN THE
PRECIPITATION CHANCES FOR MUCH OF THURSDAY INTO EARLY FRIDAY
MORNING. GFS IS A BIT QUICKER THAN NAM RETURNING MOISTURE AND DEEP
LAYER THETA-E ADVECTION TO DRIVE THUNDERSTORM CHANCES AGAIN ON
FRIDAY BEFORE A PUSH OF COOLER AND DRIER AIR EVENTUALLY CUTS OFF THE
SHOWER CHANCES ON SATURDAY.
&&

.AVIATION 29/12Z...
LOC MVFR VSBY THIS MORNING WILL QUICKLY IMPROVE. WIDELY SCT -SHRA
ACROSS NW IA WILL MOVE NE INTO MN. VFR CONDS EXPECTED IN LARGE PART
FOR THE NEXT 24 HOURS WITH VARYING CIGS AOB 050. SCT -SHRA/-TSRA
WILL DEVELOP BY EARLY THIS AFTN AND CONTINUE ACROSS MAINLY CENTRAL
AND WRN AREAS THROUGH SUNSET WITH CIGS 025-030. COLD FRONT ENTERING
NW IA LATE IN PERIOD WILL INCREASE CHC OF -SHRA AFTER 08Z FOR CENT
AND WRN AREAS. COULD HAVE THUNDER IN THE VCNTY LATE IN PD...BUT PROB
TOO LOW TO MENTION AT THIS TIME.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

LONGER TERM...JUNGBLUTH
AVIATION/SHORT TERM...MOYER

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
531 AM CDT TUE MAY 29 2007

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-
081>086-092>097-301045-
EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO-
POCAHONTAS-HUMBOLDT-WRIGHT-FRANKLIN-BUTLER-BREMER-SAC-CALHOUN-
WEBSTER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK-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-DAVIS-
531 AM CDT TUE MAY 29 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR MUCH OF CENTRAL IOWA.

.DAY ONE...TODAY AND TONIGHT

ISOLATED THUNDERSTORMS ARE EXPECTED TO DEVELOP DURING THE
AFTERNOON AND EARLY EVENING HOURS...AND ARE MOST LIKELY TO AFFECT
AREAS FROM WEST CENTRAL INTO NORTHERN IOWA. THE COVERAGE SHOULD
DIMINISH GREATLY AROUND SUNSET. NO SEVERE WEATHER IS ANTICIPATED.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

THUNDERSTORMS ARE EXPECTED TO BECOME MORE WIDESPREAD BY WEDNESDAY
AFTERNOON...AND WILL BE ACTIVE ACROSS CENTRAL IOWA UNTIL THURSDAY
MORNING. POTENTIAL FOR SEVERE WEATHER IS MINIMAL. HOWEVER...DEEP
MOISTURE AND SLOW MOVEMENT WILL PRODUCE AREAS OF HEAVY RAINFALL...
EXCEEDING 1 TO 2 INCHES IN A FEW HOURS IN SOME LOCATIONS. RENEWED
RIVER FLOODING OR COUNTY WIDE FLOODING IS POSSIBLE...ESPECIALLY
FROM ATLANTIC NORTHWEAST TOWARD IOWA FALLS. THUNDERSTORMS ARE
AGAIN POSSIBLE ON FRIDAY...BEFORE A DRIER SPELL SETS IN.

.SPOTTER INFORMATION STATEMENT...
THE POTENTIAL FOR SPOTTER ACTIVATION DUE TO SEVERE WEATHER IS LOW
FOR THE TIME BEING...HOWEVER REPORTS OF HEAVY RAIN AND FLOODING
MAY BE NEEDED.

JUNGBLUTH