Flooding in Iowa, September 15 to 30, 2004

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
631 AM CDT CDT WED SEP 15 2004

.DISCUSSION...

LOOKS LIKE DRY SLOT HAS GOTTEN INTO THE CWA ABOUT 2 HOURS FASTER
THAN ANTICIPATED. THIS HAS BIG IMPACTS ON GOING WX/POP AND QPF
FORECAST. HAVE UPDATED GRIDS AND NEW ZONES WILL BE OUT SHORTLY TO
BETTER REFLECT FASTER MOVEMENT.
&&

.PREV DISCUSSION..
MAIN SHORT TERM FORECAST PROBLEMS ARE ONGOING WEATHER TODAY AND ITS
IMPACTS ON TEMPERATURES AND FOG POTENTIAL TONIGHT.

07Z WATER VAPOR IMAGERY INDICATED STRONG SHORTWAVE TROUGH ENTERING
WESTERN NEBRASKA WITH STRONG H300 DIFFLUENCE AHEAD OF FEATURE.
WIDESPREAD PRECIP WAS SEEN ON MOSAICS BOTH ALONG THE COLD FRONT AND
WARM FRONT.

MODELS ALREADY BEGAN TO DIVERGE WITH HANDLING OF THIS FEATURE IN THE
FIRST SIX HOURS OF THE FORECAST WITH GFS SEEMING TO BE A BIT
CONVECTIVELY CONTAMINATED. EXPECT WAVE TO SLOW A BIT OVER THE NEXT
FEW HOURS AS IT INTERACTS WITH FRONTAL ZONE AND CYCLOGENESIS
INCREASES. THAT BEING SAID BEST SHOT OF PRECIP AFTER 12Z LOOKS TO BE
IN THE NORTHEAST CWA...WITH PRECIP CHANCES DROPPING OF FAST TO THE
SOUTH AFTER 13Z. ALTHOUGH THE RAIN WILL CONTINUE A BIT LONGER TODAY
WONT CONTINUE FLOOD WATCH AS HEAVIEST RAINS HAVE ALREADY
FALLEN...AND WILL JUST HAVE TO COVER THINGS WITH WARNINGS AS NEED
BE. WAVE LOOKS TO CLEAR ENTIRE CWA AND STRONG SUBSIDENCE SETS IN.
THIS SHOULD SCOUR OUT CLOUDS PRETTY QUICKLY SAVE FOR SOME WRAP
AROUND STRATUS TO THE NORTHEAST. TEMPS SHOULD MIX OUT TO H850 PRETTY
EASY IN THE SOUTH WITH LOTS OF SUNSHINE AND POST FRONTAL WIND...BUT
WILL PROBABLY ONLY BE A FEW DEGREES WARMER THAN NOW IN THE
NORTHEAST. TONIGHT SFC RIDGE SETTLES OVER AREA DROPPING OF WINDS.
WITH ABUNDANT LOW LEVEL MOISTURE...INVERSION STRENGTHENING BY LL
WARM ADVECTION AND WEAK BL WINDS...EXPECT TO SEE A GOOD RADIATIONAL
FOG EVENT OVERNIGHT. DENSE FOG WILL ALSO BE POSSIBLE ACROSS THE SE
AS WEAKEST WINDS WILL OCCUR AT TIME OF MAX RADIATIONAL COOLING.
DESPITE GOOD COOLING...THINK MODELS ARE UNDER DOING SFC MOISTURE AND
WILL GO NOT AS COLD AS GUIDANCE.

AFTER THURSDAY MORNING WX SHOULD BE QUIET THROUGH SATURDAY. MODELS
CONTINUE TO SHOW A SERIES OF SHORTWAVES SLIDING CROSS THE AREA
THU-SAT. BUT SFC RIDGE TO THE SOUTH WILL SERIOUSLY IMPEDE ANY DECENT
MOISTURE RETURN SO WILL CONTINUE DRY FORECAST. DID ADD SOME SMALL
POPS ON SUNDAY AS STRONGER RETURN FLOW SETS UP...BUT MADE NO MAJOR
CHANGES TO REST OF THE FORECAST.

.FSD...WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
NE...NONE.
IA...NONE.

&&

JRM

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SIOUX FALLS SD
541 AM CDT WED SEP 15 2004

SDZ038>040-050-052>071-MNZ071-072-080-081-089-090-097-098-
IAZ001>003-012>014-020>022-031-032-NEZ013-014-161200-
AURORA-BEADLE-BON HOMME-BROOKINGS-BRULE-BUENA VISTA IA-
CHARLES MIX-CHEROKEE IA-CLAY-CLAY IA-COTTONWOOD MN-DAKOTA NE-
DAVISON-DICKINSON IA-DIXON NE-DOUGLAS-GREGORY-HANSON-HUTCHINSON-
IDA IA-JACKSON MN-JERAULD-KINGSBURY-LAKE-LINCOLN-LINCOLN MN-
LYON IA-LYON MN-MCCOOK-MINER-MINNEHAHA-MOODY-MURRAY MN-NOBLES MN-
OBRIEN IA-OSCEOLA IA-PIPESTONE MN-PLYMOUTH IA-ROCK MN-SANBORN-
SIOUX IA-TURNER-UNION-WOODBURY IA-YANKTON-
541 AM CDT WED SEP 15 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST SOUTH DAKOTA...
SOUTHWEST MINNESOTA...NORTHWEST IOWA...AND NORTHEAST NEBRASKA.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS...
SCATTERED THUNDERSTORMS ARE POSSIBLE THROUGH THE MORNING HOURS.
THESE STORMS ARE NOT EXPECTED TO BECOME SEVERE.

FLOODING...
ALTHOUGH THE HEAVIEST RAIN HAS ENDED ACROSS THE AREA. LOW LAND
FLOODING MAY STILL OCCUR ACROSS NORTHWEST IOWA AND SOUTHWEST
MINNESOTA DUE TO RECENT RAINFALL. RIVERS AND STREAMS WILL APPROACH
BANK FULL CONDITIONS TODAY AND PEOPLE IN THIS AREA SHOULD STAY ALERT
FOR FURTHER RIVER STATEMENTS.

WIND AND FOG...
A RIDGE OF HIGH PRESSURE WILL SETTLE OVER THE REGION TONIGHT
CAUSING CLEAR SKIES AND LIGHT WINDS. THESE CONDITIONS...COMBINED
WITH MOISTURE WILL CAUSE AREAS OF FOG TO DEVELOP EAST OF THE
JAMES RIVER VALLEY OVERNIGHT. FOG MAY BECOME LOCALLY DENSE WITH
VISIBILITIES BELOW A HALF OF A MILE.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT.

&&

FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE AT
WWW.CRH.NOAA.GOV/FSD. THIS INCLUDES THE GRAPHICAL HAZARDOUS
WEATHER OUTLOOK.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
628 AM CDT WED SEP 15 2004

..TIME...   ...EVENT...     ...CITY LOCATION...      ...LAT.LON...
..DATE...   ....MAG....     ..COUNTY LOCATION...ST.. ...SOURCE....
            ..REMARKS..

0530 AM     FLOOD            SPIRIT LAKE             43.42N 95.11W
09/15/2004                   DICKINSON          IA   CO-OP OBSERVER

            ADDITIONAL 4.09 INCHES OF RAIN SINCE MIDNIGHT. ADDED TO
            STORM TOTAL FOR A TOTAL OF 7.95 INCHES. LOTS OF STREET
            FLOODING IN THE CITY OF SPIRIT LAKE.

0523 AM     FLOOD            ROUND LAKE              43.54N 95.47W
09/15/2004                   NOBLES             MN   TRAINED SPOTTER

            5.10 INCHES ADDITIONAL RAINFALLL SINCE 700 PM LAST NIGHT.

            STORM TOTAL IS 6.50 INCHES. LOTS OF WATER IN THE STREETS.

&&

DEMORIN

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
638 AM CDT WED SEP 15 2004

..TIME...   ...EVENT...     ...CITY LOCATION...      ...LAT.LON...
..DATE...   ....MAG....     ..COUNTY LOCATION...ST.. ...SOURCE....
            ..REMARKS..

0530 AM     FLOOD            1 W DICKENS             43.13N 95.04W
09/15/2004                   CLAY               IA   TRAINED SPOTTER

            HIGHWAY 18 UNDER WATER

0530 AM     FLOOD            S TERRIL                43.31N 94.97W
09/15/2004                   DICKINSON          IA   TRAINED SPOTTER

            COUNTY ROAD B17 SOUTH OF TERRIL...BUT STILL IN CLAY
            COUNTY. ONE LANE UNDER WATER. WATER STILL
            RISING...OFFICIALS CONSIDERING CLOSING ROAD.

&&

DEMORIN