Flash Flooding in Minnesota, August 17 to 18, 2005

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
340 PM CDT WED AUG 17 2005

.DISCUSSION...TONIGHT THROUGH SATURDAY
POCKET OF DRY AIR HAS KEPT ERN MN INTO WI PRECIP FREE TODAY. WATER
VAPOR LOOP SHOWS DEEP UPPER LOW IN NORTHERN ALBERTA WITH IMPRESSIVE
TROUGH EXTENDING SOUTHWARD TO THE NW STATES. THERE ARE A COUPLE
SHORT WAVES IN ADVANCE OF THE TROUGH. THE FIRST ONE MOVING INTO WRN
IA AND SWRN MN ATTM IS ASSOCIATED WITH A BROAD AREA OF SHOWERS...BUT
IS WEAKENING. THE SECOND WAVE IS PACKING MORE PUNCH AND WILL BRING
SOME DECENT RAIN TONIGHT...ESPECIALLY TO THE SOUTHERN TWO THIRDS OF
THE CWA. THIS WILL PROBABLY BEGIN AS SOME SORT OF MCS IN SD. 90 KNOT
JET OVER NORTHERN COLORADO TRANSLATING EASTWARD...PUTTING SRN MN AND
WC WISC INTO FAVORABLE AREA FOR LIFT. THETA-E PROFILES LOOK GOOD AND
SHOW INCREASING MOISTURE. EXCELLENT WARM ADVECTION IN THIS AREA AS
WELL...ALTHO WINDS DO WEAKEN OVERNIGHT. RAIN SHOULD END THU MIDDAY
AROUND ULM/FRM BUT PROBABLY CONTINUE INTO THURSDAY EVENING AROUND
EAU. ALL MODELS IN GOOD AGREEMENT ON THIS SCENARIO.

MEANWHILE STRENGTHENING SFC LOW IN CNTRL SD WITH WRM FNT XTNDG
TOWARD DULUTH...AND SOME POTENT STORMS HAVE DEVELOPED IN ND AND WRN
SD. RUC SHOWS DECENT INSTABILITY AND SHEAR IN ND AND WRN/CNTRL SD
THROUGH THIS AFTERNOON. SOME STORMS MAY TREK INTO WC MN BUT PROBABLY
STAY NORTH OF MOX/AXN.

ATMOSPHERE WILL BE RATHER STABLE TOMORROW AND TOMORROW NIGHT IN THE
WAKE OF WIDESPREAD RAIN TONIGHT AND THURSDAY OVER MUCH OF CWA. SOME
QUESTION FRIDAY RE EXTENT OF SVR THREAT. GFS HAS THE SFC LO MUCH
FARTHER NORTH ALONG WITH A RATHER UNSTABLE ATMOSPHERE IN EC/SC MN
AND WC WISC DURING MIDDAY...WHEN COLD FRONT ARRIVES. NAM QUITE A BIT
DIFFERENT AND REVS UP LO IN KS AND TRACKS IT ACROSS IOWA. AM
SKEPTICAL OF THE NAM SFC SOLUTION SINCE THIS IS A BIT REMOVED FROM
ITS UPPER JET...WHICH IS JUST SOUTH OF THE CANADIAN BORDER ON
FRIDAY. GFS SFC PATTERN SEEMS MORE REALISTIC...BUT MOVES FRONT
THROUGH PRETTY QUICKLY ON FRIDAY. COOL/DRY AIR ON THE WAY LATER
FRIDAY NIGHT AND SATURDAY.

LONGER TERM...SATURDAY NIGHT THROUGH WEDNESDAY
EXTENDED FCST PD BEGINS WITH THE FA ON THE BACKSIDE OF DEPARTING
CLOSED UPR LOW IN S CNTRL ONTARIO AND SFC RIDGING BUILDING INTO WRN
MN FROM THE DAKOTAS. SFC HI SHUD SLOWLY PUSH EWRD THRU THE BEGINNING
OF NEXT WK...REACHING THE CNTRL GREAT LAKES/OH VALLEY BY MID WEEK.
WITH RIDGING ALOFT...PCPN CHCS WL BE MINIMAL THRU THE END OF THE
WKEND AND /AT LEAST/ MON. WITH LO PRES APPROACHING FROM THE W LATE
TUE AND TUE NGT /AS DEPICTED BY THE 12Z GFS AND 00Z ECMWF/...PCPN
CHCS WL AGAIN INCR TUE AND INTO WED WITH WAA AND S/W KICKED AHD OF
THE SYSTEM...SO INTRODUCED CHC POPS TO AT LEAST A PORTION OF THE FA
AFT 12Z TUE.

TEMP WISE...PD WL BEGIN COOL...WITH SFC HI MOVING IN AND H8 TEMPS IN
THE SINGLE DIGITS IN SOME AREAS. BOTH AFTN AND MRNG TEMPS SHUD SHOW
A SLOW INCR TO NR NORMAL LEVELS BY THE END OF THE PD...WITH A RETURN
TO SLY SFC WINDS AS THE HI PUSHES EWRD.

THANKS FOR THE COORD ABR AND FSD.

.MPX WATCHES/WARNINGS/ADVISORIES...
.MN...NONE.
.WI...NONE.

&&

TDK/KAT

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
128 PM CDT WED AUG 17 2005

MNZ041>043-047>050-055-181130-
BENTON-DOUGLAS-MORRISON-POPE-STEARNS-STEVENS-SWIFT-TODD-
128 PM CDT WED AUG 17 2005

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WEST CENTRAL AND
CENTRAL MINNESOTA.

.DAY ONE...REST OF TODAY AND TONIGHT

THUNDERSTORMS WILL BE POSSIBLE THIS AFTERNOON AND EVENING NEAR
A WARM FRONT STRETCHING ACROSS CENTRAL MINNESOTA. ALTHOUGH
ORGANIZED SEVERE WEATHER IS NOT ANTICIPATED...THE POSSIBILITY OF A
FEW STORMS PRODUCING LARGE HAIL AND DAMAGING WINDS CANNOT BE RULED
OUT. HEAVY DOWNPOURS AND DANGEROUS LIGHTNING CAN ALSO BE EXPECTED
WITH ANY THUNDERSTORMS THAT ARE ABLE TO DEVELOP.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FRIDAY...AS WARM AND
UNSTABLE AIR SURGES NORTH AHEAD OF AN APPROACHING COLD FRONT. THE
RISK FOR SEVERE WEATHER INCLUDES DAMAGING WINDS...LARGE HAIL...AND
POSSIBLE TORNADOES.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTER ACTIVATION WILL NOT BE LIKELY TODAY OR TONIGHT.

MNZ054-056-057-064-065-067-073>076-082>084-091>093-181130-
BLUE EARTH-BROWN-CHIPPEWA-FARIBAULT-FREEBORN-KANDIYOHI-LAC QUI PARLE-
LE SUEUR-MARTIN-NICOLLET-REDWOOD-RENVILLE-SIBLEY-WASECA-WATONWAN-
YELLOW MEDICINE-
128 PM CDT WED AUG 17 2005

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WEST CENTRAL AND
SOUTH CENTRAL MINNESOTA.

.DAY ONE...REST OF TODAY AND TONIGHT

THUNDERSTORMS WILL BE POSSIBLE THIS EVENING AND OVERNIGHT AS AN
UPPER LEVEL STORM SYSTEM MOVES INTO WESTERN MINNESOTA. ALTHOUGH
ORGANIZED SEVERE WEATHER IS NOT ANTICIPATED...THE POSSIBILITY OF A
FEW STORMS PRODUCING LARGE HAIL AND DAMAGING WINDS CANNOT BE RULED
OUT. HEAVY DOWNPOURS AND DANGEROUS LIGHTNING CAN ALSO BE EXPECTED
WITH ANY THUNDERSTORMS THAT ARE ABLE TO DEVELOP.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THURSDAY AND THURSDAY
NIGHT SOUTH AND EAST OF A LINE FROM NEW PRAGUE...TO MANKATO AND
FAIRMONT. SEVERE STORMS ARE POSSIBLE BY THURSDAY AFTERNOON AS WARM
AND UNSTABLE AIR SURGES NORTH AHEAD OF AN APPROACHING COLD FRONT.
ANOTHER RISK FOR SEVERE THUNDERSTORMS EXISTS FRIDAY AND FRIDAY
EVENING AS THE COLD FRONT MOVES ACROSS THE AREA. THE RISK FOR SEVERE
WEATHER INCLUDES DAMAGING WINDS...LARGE HAIL...AND POSSIBLE
TORNADOES.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTER ACTIVATION WILL NOT BE LIKELY TODAY OR TONIGHT.

MNZ044-045-051>053-058>063-066-068>070-077-078-085-WIZ014>016-
023>028-181130-
ANOKA-BARRON-CARVER-CHIPPEWA-CHISAGO-DAKOTA-DUNN-EAU CLAIRE-GOODHUE-
HENNEPIN-ISANTI-KANABEC-MCLEOD-MEEKER-MILLE LACS-PEPIN-PIERCE-POLK-
RAMSEY-RICE-RUSK-SCOTT-SHERBURNE-ST CROIX-STEELE-WASHINGTON-WRIGHT-
128 PM CDT WED AUG 17 2005

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST CENTRAL
MINNESOTA AND WEST CENTRAL WISCONSIN.

.DAY ONE...REST OF TODAY AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THURSDAY AND THURSDAY
NIGHT SOUTH AND EAST OF A LINE FROM EAU CLAIRE...TO THE TWIN CITIES
AND NEW PRAGUE. SEVERE STORMS ARE POSSIBLE BY THURSDAY AFTERNOON AS
WARM AND UNSTABLE AIR SURGES NORTH AHEAD OF AN APPROACHING COLD
FRONT. ANOTHER RISK FOR SEVERE THUNDERSTORMS EXISTS FRIDAY AND FRIDAY
EVENING AS THE COLD FRONT MOVES ACROSS THE AREA. THE RISK FOR SEVERE
WEATHER INCLUDES DAMAGING WINDS...LARGE HAIL...AND POSSIBLE
TORNADOES.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT.

KAT