Damaging Winds and Heavy Rain in Iowa, June 15, 2012

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
650 AM CDT FRI JUN 15 2012

.UPDATED 15/12Z AVIATION DISCUSSION...

.SHORT TERM.../TODAY/
WE ARE IN A VERY MESSY PATTERN AND HOW THINGS WILL EVOLVE IS
COMPLICATED.  FIRST OF ALL THERE IS AN MCV OVER THE SOUTHWEST WHICH
WILL MIGRATE NORTH NORTHEAST THIS MORNING.  IT APPEARS TO BE STRONG
ENOUGH TO HOLD TOGETHER. STORMS ONGOING IN THAT AREA ARE EXPECTED
TO LIFT NORTHEAST THIS MORNING. COMPLICATING THIS IS A STALLED/QUASI
STATIONARY FRONTAL BOUNDARY ACROSS THE NORTHWEST PART OF THE CWA.
IT IS POSSIBLE THAT AS THE MCV LIFTS NORTHEAST SOME INTERACTION WITH
THE BOUNDARY COULD OCCUR AND COVERAGE EXPANDS SOME.

THIS AFTERNOON A SHORTWAVE WILL LIFT ACROSS THE CWA AND THE
AFOREMENTIONED FRONTAL BOUNDARY WILL ONCE AGAIN BECOME THE FOCUS FOR
THUNDERSTORM DEVELOPMENT.  THE AMOUNT OF DESTABILIZATION TODAY IS OF
SOME CONCERN BECAUSE OF THE EXPANSIVE CLOUD COVER ACROSS THE REGION
FROM THE CONVECTION OVERNIGHT BUT AS DYNAMIC AS THIS SYSTEM IS
COMBINED WITH 2000-3000 CAPES AND THE THOUGHT THAT THERE WILL BE
SOME SUN TODAY I THINK THERE WILL BE NO TROUBLE SEEING THUNDERSTORMS
DEVELOP.  SHEAR IS MARGINAL AT BEST SO THE CONCERN FOR SEVERE...
WHILE IT CANNOT BE RULED OUT...IS LOW.  THE SLOW MOVING NATURE OF
THIS SYSTEM AND THE QUASI STATIONARY BOUNDARY DOES LEAD TO CONCERNS
OF THE POSSIBILITY OF HEAVY RAIN BUT MOST LOCATIONS WILL TAKE A LOT
OF MUCH NEEDED RAINFALL.

.LONG TERM.../TONIGHT THROUGH THURSDAY/
FORECAST STILL COMPLEX OVER THE NEXT 24 TO 36 HOURS AS SYSTEM BEGINS
TO EDGE EAST. CURRENTLY INVERTED TROUGH OVER THE REGION WITH WELL
DEFINED MCV OVER EASTERN NEBRASKA AND WESTERN IA...ASSOCIATED COLD
POOL EARLIER TONIGHT HAS SOMEWHAT DISSIPATED. MODELS HAVE ALL
FINALLY CAUGHT ONTO THE MCV THAT IS EXPECTED TO DRIFT NORTH THROUGH
TONIGHT WITH MOST LIKELY TRACK TO TAKE IT THROUGH CENTRAL TO
NORTHEAST IOWA BY 06Z SATURDAY. HAVE BROADBRUSHED RAINFALL AMOUNTS
OF UP TO TWO THIRDS OF AN INCH FROM 00 TO 06Z WITH LIGHTER AMOUNTS
LATE EVENING AFT 06Z TONIGHT. VERY POSSIBLE TO SEE 1 TO 2 INCHES
WITH THE MCV AS IT TRACKS NORTHEAST...WHICH WOULD BE GREAT NEWS FOR
AREA.  SEVERE CHANCES LOOK TO BE SOMEWHAT MUTED DUE TO THE CLOUD
COVER AND ONGOING CONVECTION. MCV MORE LIKELY TO PRODUCE BRIEF HEAVY
DOWNPOURS WITH MINOR STREET ISSUES IN URBAN AREAS IF IT MOVES SLOWLY
ENOUGH THIS AFTERNOON/EVENING. SOME HAIL AND WIND GUSTS ARE
CERTAINLY NOT OUT OF THE QUESTION IN THE STRONGER CELLS LATER TODAY
AND THIS EVENING BUT AN ORGANIZED SEVERE WEATHER THREAT WILL BE
HARDER TO COME BY WITH THE AMOUNT OF MESO SCALE FEATURES AND LACK OF
SIGNIFICANT SYNOPTIC FORCING TODAY. SUBJECTIVE ANALYSIS OF H850
MOISTURE FIELDS AT 00Z SHOWED A SIGNIFICANT RIBBON OF +15C DEW
POINTS FROM KMSP TO KDFW AND THEN INTO THE GULF. THIS TRANSLATES TO
NEARLY 2 INCHES OF PWAT OVER THE REGION LATE THIS AFTERNOON AND THIS
EVENING. DEPENDING ON HOW THE MESOSCALE FORCING WITH THIS MCV
EVOLVES...THERE IS STILL A POTENTIAL FOR SOME MINOR URBAN HYDRO
ISSUES IF CONVECTION CAN GEN UP QPF AMOUNTS CLOSER TO 2 TO 3 INCHES
AT SOME LOCATIONS. AGAIN URBAN CONCERNS OUTWEIGH ANY OTHER
LOCATIONS...AND CERTAINLY ONGOING SOIL CONDITIONS...AND CROPS WILL
SOAK UP ANY SIGNIFICANT RAINS THAT MIGHT OCCUR. 3HR FFW GUIDANCE
SHOWS MANY LOCATIONS NEED BETWEEN 3 TO 4 INCHES BEFORE PROBLEMS WILL
ARISE. SOME PARAMETERS POINT TO LOCALLY HEAVY DOWNPOURS...GFS
SOUNDINGS SHOWING WARM CLOUD DEPTHS OF ABOUT 12KFT WITH MODEST CAPE
OF 700 J/KG AND PWATS OF 1.9 AT 18Z AND WITH MORE CAPE BY 00Z AND
SLIGHTLY DRIER SOUNDING. FOR NOW...WILL NOT BE ADDING LOCALLY HEAVY
RAIN WORDING TO ZONES...PRIMARILY DUE TO SOME UNCERTAINTY...EVEN
NOW...HOW QUICKLY THE MCV/MCS WILL MOVE NORTHEAST THIS EVENING. WILL
LATE DAY SHIFT EVALUATE RAIN RATES AND MAKE ANY NEEDED ADJUSTMENTS.

AS THE MESO SYSTEM EXITS SATURDAY MORNING THE MAIN SYNOPTIC FRONT
WILL BEGIN TO TRACK SOUTHEAST ACROSS THE REGION. THIS WILL BRING
ANOTHER ROUND OF SHOWERS AND THUNDER TO THE REGION THROUGH SATURDAY
NIGHT WITH POTENTIAL FOR ANOTHER HALF INCH OR SO OVER THE AREA.
HIGHS SATURDAY WITH MORE CLOUDS AND RAIN POTENTIAL WILL BE COOLER
BUT AS THE SYSTEM SHIFTS SOUTH ON SUNDAY AND WE DRY OFF OVER MOST OF
THE REGION SANS THE SOUTH PORTION...WE WILL SEE MILDER TEMPS BY LATE
DAY AS WARM AIR ADVECTION BEGINS TO RETURN. SOME QUESTIONS ABOUT HOW
ACTIVE RETURN MOISTURE FLOW WILL BE SOUTH...BUT FEEL THAT
MORNING/AFTERNOON CHANCES STILL POSSIBLE FAR SOUTH AND THEN
OVERNIGHT THE FRONT LIFTS RAPIDLY NORTH. MONDAY THROUGH WED LOOK
VERY WARM AND BREEZY WITH A FULLY MIXED BOUNDARY LAYER. WITH THE
WARM FRONT INTO SOUTHERN MN AND H850 TEMPS IN THE 21 TO 24C RANGE
FOR 3 DAYS...HIGHS SHOULD BE WELL INTO THE 90S ON MONDAY WITH UPPER
80S TO LOWER 90S FOR THE SOUTH ON TUES/WED. HUMIDITY LEVELS WILL BE
UP AS WELL WITH DEW POINTS IN THE 60S TO NEAR 70. BY LATE WEDNESDAY
ANOTHER FRONT WILL PASS THROUGH THE REGION AS THE LOW TRACKS
NORTHEAST. THIS WILL BRING A RENEWED CHANCE FOR THUNDER ACROSS THE
REGION WED...WED NIGHT AND THURSDAY AS THE FRONT DROPS SOUTHEAST.
HIGHS SHOULD COOL INTO THE 70S TO LOWER 80S BY THURSDAY.

&&

.AVIATION...15/12Z
VFR CIGS EXPECTED OVER THE TAF LOCATIONS BUT MAY DROP TO MVFR IN
TSRA.  A PERSISTENT CLUSTER OF STORMS OVER SOUTHWEST IA IS EXPECTED
TO SHIFT NORTHEAST THIS MORNING...POSSIBLY INTO EARLY AFTERNOON.
LATER THIS AFTERNOON AND TONIGHT STORMS ARE EXPECTED TO REDEVELOP
ALONG A FRONTAL BOUNDARY AND GRADUALLY SHIFT EAST.  HEAVY RAIN IS
POSSIBLE WITH A FEW OF THESE STORMS WHICH MAY REDUCE VSBYS.

&&

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

&&

SHORT TERM...FAB
LONG TERM...REV
AVIATION...FAB

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
533 AM CDT FRI JUN 15 2012

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097-161045-
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-
533 AM CDT FRI JUN 15 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA.

.DAY ONE...TODAY AND TONIGHT

SCATTERED THUNDERSTORMS ARE EXPECTED THIS MORNING MAINLY WEST OF
INTERSTATE 35. MORE NUMEROUS THUNDERSTORMS WILL OCCUR LATER THIS
AFTERNOON THROUGH TONIGHT...MAINLY ACROSS CENTRAL AND NORTHEAST
IOWA. AN ISOLATED STORM COULD BE STRONG TO SEVERE...WITH LARGE
HAIL AND STRONG WINDS THE PRIMARY THREATS. LOCALLY HEAVY DOWNPOURS
ARE ALSO POSSIBLE AND MAY CAUSE MINOR URBAN RUNOFF PROBLEMS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

CHANCES FOR THUNDERSTORMS WILL CONTINUE SATURDAY THROUGH THURSDAY.
A FEW SEVERE STORMS MAY OCCUR FROM TIME TO TIME THROUGH SATURDAY
EVENING AND AGAIN BY WEDNESDAY AND THURSDAY OF NEXT WEEK. THE
MAIN SEVERE THREATS WILL MOST LIKELY BE LARGE HAIL AND DAMAGING
WINDS THROUGH SATURDAY EVENING. LOCALLY HEAVY DOWNPOURS ARE ALSO
POSSIBLE AND MAY CAUSE MINOR URBAN RUNOFF PROBLEMS. IT IS TOO SOON
TO DETERMINE IF SEVERE WEATHER WILL OCCUR NEXT WEDNESDAY AND THURSDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY OR TONIGHT BUT MAY BE
NEEDED SATURDAY AFTERNOON THROUGH SATURDAY NIGHT.

REV