Flash Flood Watch 2, NWS Des Moines, IA

000 
WGUS63 KDMX 190125
FFADMX

FLOOD WATCH
NATIONAL WEATHER SERVICE DES MOINES IA
825 PM CDT FRI AUG 18 2006

...FLASH FLOOD THREAT HAS DIMINISHED ACROSS SOUTHERN IOWA OVERNIGHT...

IAZ070>075-081>086-092>097-190230-
/O.CAN.KDMX.FF.A.0002.000000T0000Z-060819T0900Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CASS-ADAIR-MADISON-WARREN-MARION-MAHASKA-ADAMS-UNION-CLARKE-LUCAS-
MONROE-WAPELLO-TAYLOR-RINGGOLD-DECATUR-WAYNE-APPANOOSE-DAVIS-
INCLUDING THE CITIES OF...ATLANTIC...GREENFIELD...WINTERSET...
INDIANOLA...KNOXVILLE...OSKALOOSA...CORNING...CRESTON...OSCEOLA...
CHARITON...ALBIA...OTTUMWA...BEDFORD...MOUNT AYR...LEON...
CORYDON...CENTERVILLE...BLOOMFIELD
825 PM CDT FRI AUG 18 2006

...FLASH FLOOD WATCH IS CANCELLED...

THE FLASH FLOOD WATCH FOR PORTIONS OF SOUTH CENTRAL IOWA...
SOUTHEAST IOWA AND SOUTHWEST IOWA HAS BEEN CANCELLED. SCATTERED
THUNDERSTORMS ARE POSSIBLE OVERNIGHT...BUT HEAVY RAINFALL AND
FLASH FLOODING ARE EXPECTED TO REMAIN SOUTH AND WEST OF IOWA.
ISOLATED ADDITIONAL RAINFALL AMOUNTS UP TO ONE HALF INCH ARE
POSSIBLE THROUGH DAYBREAK.

$$

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
358 PM CDT FRI AUG 18 2006

.DISCUSSION...
UPDATE. WILL BE ISSUING A FLASH FLOOD WATCH FOR THE SOUTHERN THREE
TIER OF COUNTIES THROUGH 4 AM TONIGHT WITH ADDITIONAL RAINFALL
AMOUNTS OF 1 TO 3 INCHES POSSIBLE IN CONJUNCTION WITH RECENT HEAVY
RAINS.

&&

.PREVIOUS DISCUSSION...
CONVECTIVE SYSTEM THAT DEVELOPED OVER SOUTHEAST MONTANA HAS
MAINTAINED AND IS CURRENTLY RIDING DOWN THE INSTABILITY AXIS INTO
NORTHWEST IOWA. CLEARING SKIES OVER PORTIONS OF CENTRAL AND WEST
CENTRAL IOWA WILL AID IN KEEPING SOME INSTABILITY AHEAD OF THE
SYSTEM. A POTENT SHORT WAVE IS MOVING ACROSS SOUTHWESTERN IOWA AND
AM A LITTLE UNCERTAIN HOW THE SOUTHERN EXTENT OF THE COMPLEX WILL
REACT AS IT MOVES INTO THE SUBSIDENCE REGION OF THE SHORT WAVE. DO
EXPECT THE COMPLEX TO CONTINUE TO MOVE ACROSS THE FORECAST AREA
TONIGHT WITH A FEW SEVERE STORMS POSSIBLE. THE COMPLEX WILL
EVENTUALLY PUSH ALL OF THE PRECIPITATION SOUTH AND EAST OF THE AREA
WITH LOW STRATUS AND FOG DEVELOPING IN THE WAKE OF THE SYSTEM. A
STRONG LATE SUMMER COLD FRONT MOVES ACROSS IOWA ON SATURDAY AND THIS
ALONG WITH STRATUS LINGERING MUCH OF THE DAY WILL LEAD COOL HIGHS
AND NON DIURNAL TEMPERATURES DURING THE DAY. SOME DRIZZLE/SHOWERS
ARE POSSIBLE HOWEVER WITH THE LOW LEVEL COLD AIR LEADING THE
WAY...TOPS WILL BE VERY SHALLOW WITH THE MOISTURE FOCUSED BELOW 850
MB AND REDUCING INSTABILITY. HAVE THEREFORE REMOVED THE THREAT OF
THUNDER.

CANADIAN HIGH PRESSURE ENTERS THE REGION SATURDAY NIGHT. DESPITE THE
DRY AIR IN PLACE ON SUNDAY...KEPT HIGHS TOWARD THE LOWER END OF
GUIDANCE WITH HIGHS ONLY REACHING THE UPPER 70S WITH MIXING TO 850
MB. THE GFS HAS BEEN CONSISTENT THE PAST 3-4 RUNS BRINGING A
BOUNDARY THROUGH ON TUESDAY AND CURRENTLY WILL MAINTAIN LOW POPS.
THE GFS ENSEMBLES ARE IN DISARRAY BEYOND 150 HRS AND THIS COMBINED
WITH PLACEMENT AND TIMING ISSUES WITH THE CANADIAN AND ECMWF FOR
FEATURES EMBEDDED IN THE NORTHWEST FLOW...HAVE NO CONFIDENCE TO
CHANGE THE PRECIPITATION TIMING FOCUS FROM WEDNESDAY NIGHT AND
THURSDAY. EXPECT SEASONAL TEMPERATURES THROUGHOUT THE EXTENDED.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...FLASH FLOOD WATCH FOR THE
SOUTHERN THREE TIER OF COUNTIES UNTIL 4 AM.

&&

MYERS/DONAVON

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
555 AM CDT FRI AUG 18 2006

IAZ044>050-057>062-070>075-081>086-092>097-191100-
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-
555 AM CDT FRI AUG 18 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE SOUTHERN HALF OF IOWA.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS WILL AFFECT MUCH OF THE SOUTHERN HALF OF IOWA THIS
MORNING. SOME STORMS WILL PRODUCE VERY HEAVY RAINS WITH RATES IN
EXCESS OF AN INCH PER HOUR...AND 12 HOUR RAINFALL TOTALS LOCALLY
UP TO SIX INCHES THROUGH NOON. THIS MAY RESULT IN FLOODING WITH PONDING
WATER ON ROADS AND RISES IN SMALL STREAMS AND CREEKS.

SCATTERED THUNDERSTORMS WILL STILL BE POSSIBLE INTO TONIGHT. THESE
MAY ALSO PRODUCE LOCALLY HEAVY RAINS...BUT NOT AS SIGNIFICANT AS
WHAT IS EXPECTED THIS MORNING.

A FEW STORMS MAY STILL BE SEVERE WITH DAMAGING WINDS AND LARGE
HAIL...BUT THE THREAT IS RELATIVELY LOW.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THERE WILL BE LOW CHANCES FOR NON-SEVERE THUNDERSTORMS SATURDAY
EAST OF INTERSTATE 35.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS ARE ENCOURAGED TO REPORT FLOODING AND HEAVY RAINFALL
AMOUNTS.  THE POTENTIAL FOR SEVERE WEATHER ACTIVATION IS MINIMAL.

IAZ004>007-015>017-023>028-033>039-191100-
EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO-
POCAHONTAS-HUMBOLDT-WRIGHT-FRANKLIN-BUTLER-BREMER-SAC-CALHOUN-
WEBSTER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK-
555 AM CDT FRI AUG 18 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE NORTHERN HALF OF IOWA.

.DAY ONE...TODAY AND TONIGHT

CHANCES FOR THUNDERSTORMS WILL REMAIN IN THE FORECAST THROUGH
TONIGHT.  A FEW STORMS MAY STILL BE SEVERE WITH DAMAGING WINDS AND LARGE
HAIL...AS WELL AS LOCALLY HEAVY RAINS...BUT THE THREAT IS RELATIVELY LOW.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THERE WILL BE LOW CHANCES FOR NON-SEVERE THUNDERSTORMS SATURDAY
EAST OF INTERSTATE 35.

.SPOTTER INFORMATION STATEMENT...

ALTHOUGH SPOTTERS MAY BE NEEDED TO REPORT HEAVY RAIN OR ACTIVATE
FOR SEVERE WEATHER THROUGH TONIGHT...THE POTENTIAL IS RELATIVELY LOW.

SMALL