Funnel Clouds and Heavy Rain in Iowa, July 6, 2010

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1240 PM CDT TUE JUL 6 2010

...UPDATED FOR 18Z AVIATION DISCUSSION...

.SHORT TERM /TODAY/...
WEAK BOUNDARY WILL SLOWLY WASH OUT OVER THE STATE TODAY AS A MORE
VIGOROUS FRONT DEVELOPS ACRS THE DAKOTAS INTO WESTERN NEBRASKA.
ONGOING CONVECTION IN MO/KS APPEARS THAT IT WILL PUSH INTO SOUTHERN
IA BY DAYBREAK.  BOTH THE HRRR AND SPC WRF WANT TO WEAKEN AND
DISSIPATE THIS PCPN DURING THE MORNING...BUT RECENT RADAR TRENDS ARE
SHOWING ADDITIONAL DEVELOPMENT.  WILL LIKELY HOLD ONTO THE FLASH
FLOOD WATCH UNTIL EXPIRATION TIME GIVEN THE TRAJECTORY OF THE PCPN.
OTHERWISE...APPEARS MAIN THREAT OF SHRA/TSRA WILL REMAIN IN THE
SOUTHEAST WHERE MOISTURE PLUME WILL REMAIN IN PLACE...ALBEIT
ISOLD/SCT GIVEN WEAK FORCING AND SHEAR. REMAINDER OF THE
CWA...ESPECIALLY THE FAR WEST IS EXPECTED TO SEE A FEW BREAKS IN THE
CLOUDINESS WHICH SHOULD HELP TEMPS INTO THE 80S IN MOST AREAS.

.LONG TERM /TONIGHT THROUGH MONDAY/...
DIFFUSE FRONT REMAINS OVER THE AREA WITH APPROACHING UPPER LEVEL
SHORT WAVE ADVANCING EAST FROM THE NORTHERN ROCKIES TO PLAINS BY
TUES NIGHT THROUGH EARLY THURSDAY. COLUMN OF SATURATED AIR NOT
EXPECTED TO MOVE MUCH IN THE NEXT 24 HOURS...WITH SLIGHT SOUTHWARD
DRIFT THROUGH THIS AFTERNOON...FOLLOWED BY NORTHWARD RETURN AS WAVE
APPROACHES FROM THE NORTHWEST. 00Z GFS PWAT PROG SHOWS 2 TO 2.25
INCH AXIS EXTENDING ACROSS SOUTH CENTRAL THROUGH NORTHEAST IA BY 12Z
WED. WITH THE MOISTURE RETURNING AS UPPER LEVEL DYNAMICS
INCREASE...AM EXPECTING TO SEE GRADUAL INCREASE IN SHOWERS/STORMS
OVER THE FCST AREA TNT AND LIKELY ON WED INTO WED EVENING. AREAS
FAVORED FOR MORE LOCALLY HEAVY RAINFALL WOULD APPEAR GREATEST OVER
THE SOUTHEAST...AS HAS BEEN THE CASE SINCE SUNDAY EVENING. THOUGH A
BREAK SHOULD ARRIVE TODAY OVER THIS AREA...ANOTHER ROUND OF SLOW
MOVING TROPICAL SHOWERS AND THUNDER WOULD CERTAINLY CAUSE CONCERN
FOR ADDITIONAL EXCESSIVE RAINFALL AND POTENTIAL FOR FLASH FLOODING.
WILL LET THE DAY AND SWING SHIFTS EVALUATE THIS POTENTIAL FURTHER
LATER TODAY. MODELS COMING INTO AGREEMENT WITH RIDGE OF HIGH
PRESSURE FINALLY WEAKENING OVER THE MID ATLANTIC STATES. THIS WILL
ALLOW FOR THE WEAK AND DIFFUSE FRONT TO MOVE FAR ENOUGH EAST TO CUT
OFF DEEP TROPICAL MOISTURE PLUME FOR SEVERAL DAYS. AS H500 FLOW
BECOMES MORE NORTHWESTERLY BY LATE THURSDAY...SLIGHTLY COOLER AND
DRIER AIR WILL ADVANCE SOUTHEAST. EXPECTING TO SEE PATCHY TO
POSSIBLY WIDESPREAD FOG AS HIGH BUILDS OVER THE AREA WHERE SOIL
REMAINS SATURATED. BOTH FRIDAY AND SATURDAY MORNINGS MAY SEE SOME
FOG ACROSS THE REGION. LATE IN THE WEEKEND ANOTHER SHORT WAVE RIDES
EAST OVER THE NOW FLATTER H500 RIDGE. THIS WILL INCREASE LEE SIDE
TROUGHING BY LATE SUNDAY AND INCREASE TROPICAL PLUME BACK INTO THE
GREAT PLAINS. MODELS INDICATE ANOTHER PERIOD OF MODERATE RAIN
POSSIBLE BY LATE IN THE PERIOD SUNDAY NIGHT OR MONDAY AS STRONGER
THETAE ADVECTION AND WARMER AIRMASS RETURNS TO THE AREA. HIGHS OVER
THE NEXT SEVERAL DAYS SHOULD NOT STRAY TOO FAR FROM PERSISTENCE WITH
HIGHS NEAR 80 AND LOWS IN THE 60S TO NEAR 70S THROUGH THURSDAY
MORNING. AS THE RIDGE BEGINS TO BUILD INTO THE AREA THURS NIGHT AND
FRIDAY...EXPECTING LOWS TO DROP INTO THE LOWER 60S AND 50S. BY SAT
NIGHT WARM AIR RETURNS AND GRADUALLY INCREASING TEMPS EXPECTED.

&&

.AVIATION...
06/18Z...COMPLICATED AVIATION FORECAST TODAY AS STAGNANT LOW-LEVEL
FLOW HAS TRAPPED A LOT OF MOISTURE. SCT-BKN LOW CLOUDS AT 2500-3500
THROUGH SUNSET...WITH ISOLD-SCT -SHRA/TSRA ALONG AND SOUTHEAST OF
STALLED WIND SHIFT BOUNDARY FROM KALO-JUST SOUTH OF KDMX-KLWD
THROUGH SUNSET AS WELL. SHOULD BE A BREAK OVER MIDNIGHT...WITH
POSSIBLE EXCECPTION OF KOTM...BUT THEN IFR CONDS DUE TO FOG AND LOW
STRATUS ARE LIKELY TO DEVELOP NW OF THE BOUNDARY AFTER MIDNIGHT.
FINALLY...12-18Z RETURN FLOW IS LIKELY TO DEVELOP A FAIRLY
WIDESPREAD AREA OF LOW MVFR CONDITIONS IN RA/SHRA AND ISOLD TSRA
NEAR THE MISSOURI BORDER THAT WILL MIGRATE NWD THROUGHT THE DAY WED.

&&

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

&&

SHORT TERM...COGIL
LONG TERM...REV
AVIATION...JUNGBLUTH

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
821 AM CDT TUE JUL 6 2010

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097-071330-
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-
821 AM CDT TUE JUL 6 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA.

.DAY ONE...TODAY AND TONIGHT

SCATTERED SHOWERS AND ISOLATED ARE EXPECTED ACROSS THE AREA
THROUGH TONIGHT. NO SEVERE WEATHER IS ANTICIPATED.

RIVER FLOOD WARNINGS ARE IN EFFECT FOR THE AREA. PLEASE REFER TO
THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR
FURTHER DETAILS.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED LATE
TONIGHT THROUGH THURSDAY. NO SEVERE WEATHER IS ANTICIPATED...BUT
LOCALLY HEAVY RAIN IS POSSIBLE ON WEDNESDAY SOUTHEAST OF AN
ATLANTIC TO WATERLOO LINE.

RIVER FLOOD WARNINGS ARE IN EFFECT FOR THE AREA. PLEASE REFER TO
THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR
FURTHER DETAILS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED...HOWEVER REPORTS OF HEAVY
RAINFALL WOULD BE APPRECIATED.

AW/RH