River Flood Warning 202, NWS Des Moines, IA

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
315 AM CDT MON JUL 28 2008

.UPDATED 12Z/28 AVIATION DISCUSSION.

.SHORT TERM...TODAY
MUCH LIKE PAST SEVERAL DAYS...MAIN CONCERN REMAINS CONVECTIVE
TRENDS.  100+KT JET HAS EXITED GREAT LAKES HEADING TOWARD DELMARVA
AREA WHILE MCV ASSOCIATED WITH SUN MCS...NOW APPROACHING OH
VALLEY...IS MOVING ACROSS IL.  EVEN THOUGH WE HAVE LOST SOME OF OUR
KINEMATIC FORCING...THERMODYNAMICS AND HIGH INSTABILITY CONTINUE TO
DRIVE NW-SE ORIENTED MCS.  310K MOISTURE TRANSPORT/CONVERGENCE AND
STRONG FRONTOGENETICAL FORCING ARE ALLOWING MCS TO PERSIST REALIZING
1500-2000 J/KG ELEVATED CAPES.  EFFECTIVE SHEAR/SRH MORE THAN
ADEQUATE FOR ORGANIZATION AND LINGERING SVR THREAT...ALONG WITH
OBVIOUS HEAVY RAIN AND FLOODING POTENTIAL.

QUESTION TURNS TO HOW THIS WILL PLAY OUT TODAY.  CERTAINLY NOT
PERFECT...BUT NAM SEEMS TO HAVE A BETTER HANDLE ON TRENDS THIS
MORNING AND SUGGESTS MORE REDEVELOPMENT LATER TODAY.  EXPECT REPEAT
OF TODAY...QUESTION IS WHERE.  MLCAPES BECOME EXTREME AGAIN...4000+
J/KG WITH CIN ERODING BY AFTERNOON.  A LOT WILL DEPEND ON OUR
CURRENT MCS.  IF IT LINGERS THROUGH THE MORNING...NEW DEVELOPMENT
MAY BE OVER SWRN HALF OF FORECAST AREA.  HOWEVER NAM AND GFS TRY TO
DEVELOP LOW LEVEL CONVERGENCE RIGHT IN CENTRAL IA...WHICH PROBABLY
WOULD NOT OCCUR UNLESS MCS FADES OR PUSHES TO THE S AND E.
CONFIDENCE NOT TOO GREAT IN EITHER DIRECTION AT THE MOMENT...SO HAVE
INTRODUCED RATHER BROAD CHANCE POPS FOR ENTIRE PERIOD.  DAY SHIFT
MAY VERY WELL NEED TO ISSUE FLASH FLOOD WATCH TOO ONCE FAVORED AREAS
BECOME APPARENT.

FATE OF MCS WILL HAVE A SIMILAR EFFECT ON TEMPS.  IF IT DISSIPATES
EARLY WE COULD GET HOT AGAIN.  PLAYED THE MIDDLE GROUND IN THIS
REGARD...MAINLY LEANING TOWARD PERSISTENCE.

.LONG TERM...TONIGHT THROUGH SUNDAY
CURRENT WARM FRONTAL BOUNDARY OVER NEBRASKA TO NORTHERN MO WILL
CONTINUE TO SLOWLY LIFT NORTHEAST TNT OVER NORTHERN IA. WITH HIGH
LVL MOISTURE SITUATED ALONG THE BOUNDARY AT H850 AND LLVL MOISTURE
ALSO IN PLACE ACROSS IA...STAGE IS SET FOR ANOTHER ROUND OF THUNDER
ACROSS THE REGION TNT. MODELS CONTINUE TO HAVE TROUBLE HANDLING QPF
WHILE NAILING THE FORCING VERY WELL. BOTH THE NAM AND GFS SHOW AN
AREA OF INTENSIFYING THETAE ADVECTION ALONG THE FRONT OVERNIGHT TNT
WITH LLVL JET INCREASING ACROSS THE BOUNDARY. BEST CHANCES FOR ANY
HEAVY RAINFALL WILL BE OVER NORTHERN IA...GENERALLY ALONG AND NORTH
OF US 30...TNT 3HR FFG MOSAIC SHOWS THAT FAR NW COULD TAKE IN XS OF
3 INCHES IN 3 HOURS...THOUGH EAST OF I35 GUIDANCE LOWERS TO 1.5 TO
2.5 ON AVG. TNT CONVECTION BREAKING JUST EAST OF THE H700 +12C
ISOTHERM. TONIGHTS PLACEMENT OF THAT FEATURE PLACES GREATEST THREAT
FOR CONVECTION OVER NORTHERN IA AND PERHAPS AREAS JUST EAST OF I35
AS WELL...AS FAR SOUTH AS I80. SOME UNCERTAINTY REMAINS BUT IF TNTS
CONVECTION IS ANY INDICATION...SOME SOUTHWARD DRIFTING OF STORMS IS
LIKELY. NEXT COURSE IS OLD DOLLY. REMNANTS OF DOLLY CONTINUE TO
ADVECT NORTHEAST WITH TIME AND WAVE TO REACH THE FAR SOUTHERN IOWA
BY 00Z WED. MODELS CONTINUE TO TAKE THE SYSTEM NEARLY DUE EAST OVER
NORTHERN MO WITH LITTLE NORTHWARD PROPAGATION. GEM/EURO BLEEDING
SOME PRECIP OVER THE BORDER THROUGH EARLY WED AFTERNOON THEN WITH
SYSTEM EXITING THE AREA SHOULD SEE A BREAK ON WED AFTERNOON BEFORE
THE NEXT WAVE ARRIVES FOR WED NIGHT AND EARLY THURS. WITH CURRENT
HOT DOME SW OF THE AREA AND CONVECTION CONTINUING TO FIRE IN A
GENERALLY UNCAPPED ENVIRONMENT...MAX TEMPS WILL CONTINUE TO BE LOWER
THAN GUIDANCE THE NEXT COUPLE OF DAYS WHILE OVERNIGHT MINS WILL
RANGE FROM THE MID 60S TO LOWER 70S.  EXTENDED PATTERN THROUGH
SUNDAY SHOWS LITTLE CHANGE AS GEM/EURO/GFS SUGGEST THE CLOSE
PROXIMITY OF CURRENT QUASI-STATIONARY BOUNDARY OVER THE REGION.
CONFIDENCE ON EXACT LOCATION OF THE BOUNDARY IS LOW...GIVEN THE
POTENTIAL FOR A BACK DOOR GREAT LAKES HIGH TO MAINTAIN SOME DRYING
OVER THE GREAT LAKES BACK TOWARD IOWA. THE GFS...PER USUAL IS THE
FARTHEST EAST WITH THE PRECIP OVER THE WEEKEND WHILE THE EURO AND
GEM ARE NOT AS AGGRESSIVE WITH THE SYSTEM OVER CENTRAL IA. CURRENT
FCST IS DRY AND MAY NEED SOME ADJUSTMENT AS WE GET CLOSER TO THE
WEEKEND. TEMPS TO HOLD IN THE 80S TO NEAR 90 FOR HIGHS AND 60S FOR
LOWS.

&&

.AVIATION...28/12Z
THUNDERSTORMS CONTINUE TO BACKBUILD ACROSS WESTERN PORTIONS OF IA
THIS MORNING. WARM FRONT AT THE SFC AND ALOFT WILL BE THE FOCUS FOR
MORE STORM DEVELOPMENT LATER THIS AFTERNOON AND TNT. STORMS
EXPECTECD TO REFIRE FROM NEAR KFOD-KDSM-KOTM AFT 22Z THIS AFT AND
THEN DEVELOP ACROSS NORTHERN IA AFT 05Z. LOW CIGS NORTH THIS MORNING
WILL GO MVFR/VFR WITH MVFR/VFR CIGS LATER TODAY WITH NEW
THUNDERSTORM DEVELOPMENT. EXPECT STRONG GUSTY WINDS AND LOW VSBYS
NEAR STORMS./REV

&&

.DMX WATCHES/WARNINGS/ADVISORIES...SEVERE THUNDERSTORM WATCH IN
EFFECT UNTIL 8 AM FOR PORTIONS OF CENTRAL AND SOUTHWEST IOWA.

&&

SHORT TERM...BSS/REV
AVIATION...MS JUL 08/REV
LONG TERM...REV

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
507 AM CDT MON JUL 28 2008

IAZ033-034-044>050-057>062-070>075-081>086-092>097-291015-
SAC-CALHOUN-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-
507 AM CDT MON JUL 28 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA.

.DAY ONE...TODAY AND TONIGHT

WIDESPREAD THUNDERSTORMS WILL CONTINUE THIS MORNING MAINLY WEST
OF INTERSTATE 35 AND SOUTH OF HIGHWAY 20. THE MAIN THREAT FROM
THESE STORMS WILL BE HAIL TO GOLF BALL SIZE AND HEAVY RAINFALL.
AN ISOLATED TORNADO IS STILL POSSIBLE EARLY THIS MORNING. LOCALLY
HEAVY RAINFALL COULD LEAD TO FLASH FLOODING EARLY TODAY. RAINFALL
AMOUNTS OF 2 TO 3 INCHES MAY FALL YET THIS MORNING IN SOME OF THE
HEAVIER STORMS. ADDITIONAL SCATTERED STORMS WILL REDEVELOP LATE
THIS AFTERNOON AND TONIGHT WITH SOME STORMS NORTH OF PRODUCING
LARGE HAIL AND DAMAGING THUNDERSTORM WINDS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

CHANCES FOR THUNDERSTORMS WILL CONTINUE THROUGHOUT SATURDAY. AT
THIS TIME THE GREATER CHANCES FOR THUNDERSTORMS LOOK TO BE TUESDAY
MORNING AND AFTERNOON...AND AGAIN THURSDAY AND FRIDAY. THE CHANCES
FOR SEVERE WEATHER REMAIN UNCERTAIN AT THIS TIME FOR THE BALANCE
OF THE WEEK.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS MORNING AND AGAIN TONIGHT.

IAZ004>007-015>017-023>028-035>039-291015-
EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO-
POCAHONTAS-HUMBOLDT-WRIGHT-FRANKLIN-BUTLER-BREMER-WEBSTER-
HAMILTON-HARDIN-GRUNDY-BLACK HAWK-
507 AM CDT MON JUL 28 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA.

.DAY ONE...TODAY AND TONIGHT

SCATTERED THUNDERSTORMS ARE POSSIBLE WITH SCATTERED SEVERE THUNDERSTORMS
POSSIBLE LATE THIS AFTERNOON AND TONIGHT. THE MAIN THREAT WOULD BE LARGE
HAIL AND DAMAGING THUNDERSTORM WINDS TO 70 MPH. AN ISOLATED TORNADO
IS ALSO POSSIBLE DURING THE EVENING HOURS. THESE STORMS MAY PRODUCE
RAINFALL AMOUNTS OF 2 TO 4 INCHES WITH ISOLATED HEAVIER TOTALS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

CHANCES FOR THUNDERSTORMS WILL CONTINUE THROUGHOUT SATURDAY. AT
THIS TIME THE GREATER CHANCES FOR THUNDERSTORMS LOOK TO BE TUESDAY
MORNING AND AFTERNOON...AND AGAIN THURSDAY AND FRIDAY. THE CHANCES
FOR SEVERE WEATHER REMAIN UNCERTAIN AT THIS TIME FOR THE BALANCE
OF THE WEEK.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED TONIGHT AND EARLY TUESDAY MORNING.

REV

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
740 AM CDT MON JUL 28 2008

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

0738 AM     FLOOD            MELROSE                 40.98N 93.05W
07/28/2008                   MONROE             IA   COUNTY OFFICIAL

            ROADS CLOSED DUE TO FLOODING IN TOWN OF MELROSE.

&&

MRUSSELL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
742 AM CDT MON JUL 28 2008

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

0500 AM     FLASH FLOOD      2 W LOVILIA             41.13N 92.95W
07/28/2008                   MONROE             IA   COUNTY OFFICIAL

            CREEK FLOODED OVER COUNTY HIGHWAY 120. TIME ESTIMATED.

&&

MRUSSELL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
744 AM CDT MON JUL 28 2008

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

0743 AM     FLOOD            BAYARD                  41.85N 94.56W
07/28/2008                   GUTHRIE            IA   LAW ENFORCEMENT

            NEARLY ENTIRE COUNTY INUNDATED WITH WATER. MULTIPLE ROADS
            WASHED OUT. CARS STRANDED IN STANDING WATER AND DITCHES.
            HIGHWAY 25 CLOSED NEAR BAYARD DUE TO HIGH WATER.

&&

SMALL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
755 AM CDT MON JUL 28 2008

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

1010 PM     HAIL             3 W KELLEY              41.95N 93.72W
07/27/2008  E0.88 INCH       BOONE              IA   TRAINED SPOTTER

&&

BMOYER

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
807 AM CDT MON JUL 28 2008

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

0803 AM     FLOOD            1 W NEW VIRGINIA        41.18N 93.75W
07/28/2008                   WARREN             IA   TRAINED SPOTTER

            STREAMS OUT OF THEIR BANKS. BASEMENT FLOODING. WATER
            COMING UP STORM DRAINS.

&&

BMOYER

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
849 AM CDT MON JUL 28 2008

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

0600 AM     HEAVY RAIN       NEW VIRGINIA            41.18N 93.73W
07/28/2008  E4.70 INCH       WARREN             IA   TRAINED SPOTTER

            MEASURED BETWEEN MIDNIGHT AND 6 AM.

&&

MRUSSELL