Funnel Cloud in Iowa, July 6, 2010

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
220 PM CDT TUE JUL 6 2010

.SHORT TERM...TONIGHT THROUGH FRIDAY

RAIN CHANCES CONTINUE TO BE THE MAIN WEATHER FOCUS FOR THE NEXT FEW
DAYS.

LATEST WATER VAPOR SATELLITE IMAGERY CONTINUES TO SHOW A PLUME OF
MOISTURE STREAMING ACROSS IA INTO WI. SOME RADAR RETURNS IN THIS
MOISTURE PLUME...BUT PRETTY SPARSE. THESE SPOTTY SHOWERS WERE EAST
OF A WEAK SFC FRONT EXTENDING FROM NORTHERN WI INTO CENTRAL IA.
MEANWHILE...GOOD DRYING IN THE WATER VAPOR WEST OF THIS PLUME OF
MOISTURE...WHILE A STRONGER SHORTWAVE TROUGH WAS MOVING INTO THE
NORTHERN PLAINS.

FIRST CONSIDERATION IS THE WEAK SFC BOUNDARY THAT CONTINUES TO
LINGER OVER THE REGION. NOT MUCH CONVERGENCE AROUND IT AND THE BULK
OF THE LOW LEVEL MOISTURE TRANSPORT SHIFTS EAST THIS EVENING.
HOWEVER...A BIT OF UPPER LEVEL ENERGY TO THE SOUTH LOOKS TO WORK UP
THE BOUNDARY TONIGHT...AND SHOWERS/STORMS ARE ASSOCIATED WITH IT
OVER MO. THIS SHOULD PROVIDE ENOUGH LIFT FOR SOME SHOWER/STORM
CHANCES FOR NORTHEAST IA/SOUTHWEST WI...MOSTLY LATE. BETTER CHANCES
TO STAY DRY FARTHER NORTH.

ON WED...THE 06.12 NAM AND GFS SUGGEST THAT THE LOW LEVEL MOISTURE
TRANSPORT WILL SHIFT BACK WEST...MORE ACROSS THE EASTERN HALF OF THE
AREA...AHEAD OF THAT PIECE OF UPPER LEVEL ENERGY APPROACHING
TONIGHT. THE MOISTURE TRANSPORT/LOW LEVEL JET ARE RELATIVELY
WEAK...BUT WHEN YOU ADD ALL THE FORCING MECHANISMS TOGETHER...THERE
SHOULD BE ENOUGH FOR A DECENT SHOT OF MORE SHOWERS...POSSIBLE
THUNDERSTORMS. THE FAVORED AREAS WOULD BE NORTHEAST IA AND SOUTHWEST
INTO CENTRAL WI. MEANWHILE TO THE WEST...THAT CANADIAN/NORTHERN
PLAINS TROUGH AND SFC FRONT WILL BE MAKING PROGRESS EAST. EXPECT
SOME CONVECTION TO BE ONGOING WED MORNING IN THE VICINITY OF THAT
SFC BOUNDARY...CONTINUING THROUGH THE DAY. THIS COULD MOVE INTO
WESTERN/NORTHERN SECTIONS OF THE LOCAL AREA WED EVENING. THE
TROUGH/FRONT COMBO WILL FINALLY KICK THAT LINGER SFC BOUNDARY
EAST/SOUTH LATE IN THE DAY THU. HOWEVER...THE PROXIMITY OF THE SFC
FRONT WILL KEEP AT LEAST SMALL RAIN CHANCES GOING FOR SOUTHERN/EAST
PARTS OF THE FORECAST AREA ON THU.

BOTH THE GFS AND NAM SUGGEST AT LEAST 1500 J/KG OF SBCAPE DEVELOPING
IN THE VICINITY OF BOTH SFC BOUNDARIES ON WED. WIND SHEAR IS NOT
THAT IMPRESSIVE...AND DON/T EXPECT ANY WIDESPREAD SEVERE RISK AS A
RESULT. HOWEVER...PROBABLY ENOUGH INSTABILITY AND MINIMAL LOW LEVEL
SHEAR SUCH THAT A FEW STRONGER STORMS...PERHAPS ISOLATED
SEVERE...WILL BE POSSIBLE.

AN END TO THE MUGGY/HUMID CONDITIONS OF THE PAST SEVERAL DAYS IS
COMING. DRIER AIR WILL BE SWEEPING INTO THE AREA STARTING THU...WITH
HIGH PRESSURE BUILDING ACROSS THE UPPER MISSISSIPPI RIVER VALLEY ON
FRIDAY. THE WORK WEEK SHOULD END ON A RATHER COMFORTABLE
NOTE...TEMPERATURE/HUMIDITY-WISE.

.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY

A SOMEWHAT ZONAL LOOK TO THE UPPER LEVEL FLOW IN THE
GFS/ECMWF/GEM...ALTHOUGH THE GFS/GEM CONTINUES TO BE A BIT MORE
AMPLIFIED WITH THE TROUGHS THEY BRING THROUGH THE WEST TO EAST FLOW.
THE SOLUTIONS ARE STILL FAVORING HIGH PRESSURE FOR FRI
NIGHT/SAT...GIVING WAY TO AN UPPER LEVEL TROUGH/SFC FRONT MOVING
ACROSS THE NORTHERN PLAINS/SOUTHERN CANADA FOR SUN/MON. THE EC WOULD
THEN SLIDE ANOTHER SHORTWAVE TROUGH QUICKLY INTO THE REGION ON TUES.
THE GFS TAKES THIS FEATURE TO THE WEST AND SOUTH OF THE LOCAL AREA.
THERE IS MORE CONSISTENCY WITH THE DRY START TO THE WEEKEND ENDING
ON A POTENTIALLY WET NOTE...LINGERING INTO THE NEW WORK WEEK.
CONFIDENCE IS LESS AFTER THAT. WILL CONTINUE TO TREND WEEKEND
FORECAST TOWARD THE PCPN CHANCES FOR SUNDAY/MONDAY.

&&

.AVIATION...TONIGHT AND WEDNESDAY

NORTHWEST WINDS IN THE WAKE OF A TROUGH OF LOW PRESSURE STRETCHING
FROM CENTRAL WISCONSIN INTO EASTERN IOWA HAVE BROUGHT DRIER AIR INTO
THE TAF SITES. AS A RESULT...VFR CONDITIONS ARE PRESENT WHICH SHOULD
PERSIST THROUGH MUCH OF TONIGHT. CONCERN THEN TURNS TO BR AND FG
POTENTIAL LATE TONIGHT...DUE TO RECENT RAINFALL...LIGHT WINDS AND
MAINLY CLEAR SKIES EXCEPT FOR SOME CIRRUS. SINCE UNCERTAINTY EXISTS
ON THE EXTENT OF THE CIRRUS COVER TONIGHT AND HOW QUICK TEMPERATURES
WILL FALL GIVEN THE WARM AIRMASS IN PLACE...SO ONLY MVFR BR WAS
INCLUDED IN BOTH TAFS. FUTURE FORECASTS WILL NEED TO MONITOR THE FOG
POTENTIAL. ON WEDNESDAY...THE TROUGH OF LOW PRESSURE IS EXPECTED TO
MOVE BACK NORTH INTO THE TAF SITES. WITH DAYTIME HEATING...THIS
TROUGH MAY INITIATE SHOWERS AND EVEN A FEW THUNDERSTORMS DURING THE
AFTERNOON NEAR OR AT THE TAF SITES. OTHERWISE...VFR CONDITIONS ARE
ANTICIPATED AFTER THE BR OR FG MIXES OUT BY LATE MORNING.

&&

.HYDROLOGY...

WHILE NOT AS JUICY AS THE PAST WEEKEND...THE ATMOSPHERE WILL REMAIN
MOIST ON WED...INTO THE EARLY PART OF THU. SOME DRYING FINALLY WORKS
IN LATER ON THU. UNTIL THEN...PWS WILL BE 1.5 INCHES...150 PERCENT
OF NORMAL...AND THE WARM CLOUD DEPTH WILL BE CLOSE TO 4000 M. ANY
SHOWER OR STORM SHOULD STILL BE PRETTY EFFICIENT WHEN IT COMES TO
RAIN PRODUCTION. HOWEVER...WHILE THE ATMOSPHERE HOLDS A HEAVY RAIN
POTENTIAL...ITS LACKING GOOD/STRONG DYNAMICS TO TAKE ADVANTAGE OF
THE TROPICAL AIR MASS. AS NOTED...THERE IS LITTLE CONVERGENCE WITH
THE SFC FRONT...ONLY SMALL BITS OF UPPER LEVEL ENERGY WILL INTERACT
WITH THE BOUNDARY...AND MAYBE MORE IMPORTANTLY...THE BULK OF THE LOW
LEVEL MOISTURE TRANSPORT IS TO THE EAST. THIS WILL LIMIT THE
WIDESPREAD...HEAVY RAIN THREAT. AS RESULT...DESPITE WET AND
SATURATED GROUNDS...DON/T EXPECT COUNTYWIDE FLOOD ISSUES.
HOWEVER...LOCALLY HEAVY RAINS WILL STILL BE POSSIBLE //ESPECIALLY IF
THUNDERSTORMS DEVELOP//...AND IF THEY OCCUR...RUNOFF INTO AREA
RIVERS AND STREAMS. SOME RIVERS ARE ALREADY EXPECTED TO GO INTO
MINOR FLOOD...AND ADDITIONAL HEAVY RAIN COULD EXACERBATE THE
FLOODING POTENTIAL. WATERWAYS IN NORTHEAST IA AND SOUTHWEST WI ARE
THE PROBLEM SPOTS...AND WILL HAVE TO BE MONITORED CLOSELY OVER THE
NEXT COUPLE DAYS. BELIEVE THE RIVER FLOOD THREAT WILL BE THE MAIN
ISSUE IN RELATION TO ANY HEAVY RAIN. WILL ISSUE ONE MORE HYDROLOGIC
OUTLOOK TO OUTLINE THESE CONCERNS...AND THEN FOR MORE
INFORMATION...CONSULT THE LATEST RIVER STATEMENTS AND/OR WARNINGS.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

SHORT/LONG TERM/HYDROLOGY... RIECK
AVIATION.................... AJ

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LA CROSSE WI
331 PM CDT TUE JUL 6 2010

IAZ008>011-018-019-029-030-WIZ043-044-053>055-061-071200-
ADAMS-ALLAMAKEE-CHICKASAW-CLAYTON-CRAWFORD-FAYETTE-FLOYD-GRANT-
HOWARD-JUNEAU-MITCHELL-RICHLAND-VERNON-WINNESHIEK-
331 PM CDT TUE JUL 6 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST IOWA...
AND PORTIONS OF SOUTHWEST INTO CENTRAL WISCONSIN.

.DAY ONE...REST OF THIS AFTERNOON THROUGH TONIGHT

ISOLATED THUNDERSTORMS ARE POSSIBLE THROUGH TONIGHT. DUE TO LIMITED
INSTABILITY...BRIEF HEAVY RAIN AND LIGHTNING ARE THE MAIN HAZARDS.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

THUNDERSTORM CHANCES WILL CONTINUE ACROSS THE AREA WEDNESDAY AND
THURSDAY...BUT DUE TO LIMITED INSTABILITY...LIGHTNING AND MORE
RAINFALL ARE THE MAIN HAZARDS. THE RAINFALL ON WEDNESDAY IS
NOT EXPECTED TO BE EXCESSIVE...BUT EVEN AN INCH OF RAIN COULD
AGGRAVATE THE FLOODING POTENTIAL. A FRONT WILL SHIFT THROUGH ON
THURSDAY BRINGING IN DRIER AIR.

THUNDERSTORM CHANCES LOOK TO RETURN SUNDAY INTO MONDAY...BUT IT
IS STILL TOO EARLY TO DISCERN THE SEVERE WEATHER POTENTIAL.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED THROUGH TONIGHT. HOWEVER...ANY
RECENT RAINFALL...HIGH WATER OR FLOODING REPORTS WOULD BE GREATLY
APPRECIATED.

.EMERGENCY MANAGEMENT COORDINATION...

NO CALL IS SCHEDULED.

MNZ079-086>088-094>096-WIZ017-029-032>034-041-042-071200-
BUFFALO-CLARK-DODGE-FILLMORE-HOUSTON-JACKSON-LA CROSSE-MONROE-MOWER-
OLMSTED-TAYLOR-TREMPEALEAU-WABASHA-WINONA-
331 PM CDT TUE JUL 6 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST MINNESOTA
AND PORTIONS OF SOUTHWEST INTO CENTRAL WISCONSIN.

.DAY ONE...REST OF THIS AFTERNOON AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

THUNDERSTORM CHANCES WILL CONTINUE ACROSS THE AREA WEDNESDAY AND
THURSDAY...BUT DUE TO LIMITED INSTABILITY...LIGHTNING AND MORE
RAINFALL ARE THE MAIN HAZARDS. THE RAINFALL ON WEDNESDAY IS
NOT EXPECTED TO BE EXCESSIVE...BUT EVEN AN INCH OF RAIN COULD
AGGRAVATE THE FLOODING POTENTIAL. A FRONT WILL SHIFT THROUGH ON
THURSDAY BRINGING IN DRIER AIR.

THUNDERSTORM CHANCES LOOK TO RETURN SUNDAY INTO MONDAY...BUT IT
IS STILL TOO EARLY TO DISCERN THE SEVERE WEATHER POTENTIAL.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED THROUGH TONIGHT. HOWEVER...ANY
RECENT RAINFALL...HIGH WATER OR FLOODING REPORTS WOULD BE GREATLY
APPRECIATED.

.EMERGENCY MANAGEMENT COORDINATION...

NO CALL IS SCHEDULED.

BAUMGARDT/AJ