Flash Flood Warning 1, NWS Missoula, MT

579 
WGUS75 KMSO 202131
FFSMSO

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MISSOULA MT
331 PM MDT SUN JUN 20 2010

MTC093-202140-
/O.CAN.KMSO.FF.W.0001.000000T0000Z-100620T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SILVER BOW MT-
331 PM MDT SUN JUN 20 2010

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR CENTRAL SILVER BOW
COUNTY...

THUNDERSTORMS HAVE MOVED NORTH OF THE BUTTE AREA AND THE THREAT FOR 
FLASH FLOODING HAS DIMINISHED.

LAT...LON 4604 11259 4605 11248 4598 11243 4595 11257

$$

ALLEGRETTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
148 PM MDT SUN JUN 20 2010

...THUNDERSTORMS AND MODERATE TO HEAVY RAINFALL TO AFFECT THE
NORTHERN ROCKIES THROUGH MONDAY...
...FLOODING POTENTIAL CONTINUES FOR WESTERN MONTANA AND CENTRAL
IDAHO THROUGH TUESDAY...

.DISCUSSION...THE VERY MOIST AND ENERGETIC LOW PRESSURE SYSTEM
HAS MOVED INTO EASTERN OREGON/WEST CENTRAL IDAHO THIS AFTERNOON
AND HAS INITIATED CONVECTIVE ACTIVITY ACROSS THE AREA.
THUNDERSTORM ACTIVITY IS EXPECTED TO CONTINUE THROUGH LATER THIS
EVENING AS THE CONDITIONS WILL REMAIN PRIME FOR FURTHER
THUNDERSTORM DEVELOPMENT ACROSS THE REGION. THE POTENTIAL FOR HAIL
AND GUSTY WINDS TO ACCOMPANY THE THUNDERSTORMS WILL ALSO CONTINUE
THROUGH LATE THIS EVENING...WITH A THREAT OF LARGE HAIL FOR
PORTIONS OF CENTRAL IDAHO AND SOUTHWEST MONTANA.

THE LOW WILL THEN SHIFT TO THE NORTHEAST...CROSSING WESTERN
MONTANA TONIGHT AND SPREADING A WIDE BAND OF PRECIPITATION ACROSS
THE NORTHWEST MONTANA AND THE IDAHO PANHANDLE THROUGH MONDAY
MORNING. PERSISTENT MODERATE TO HEAVY RAINFALL WILL RESULT FROM
THIS CONCENTRATED AREA OF PRECIPITATION WRAPPING AROUND THE SYSTEM
AND COULD LEAD TO FURTHER FLOODING ISSUES.

MONDAY THROUGH SUNDAY...ANOTHER UNSEASONABLY COOL PACIFIC STORM
SYSTEM WILL BRING WIDESPREAD RAIN TO THE NORTHERN ROCKIES THROUGH
MONDAY. SIMILAR TO RECENT STORMS...A MOIST ATMOSPHERE AND HEAVY
RAIN IS ANTICIPATED. DUE TO ALREADY INCREASED FLOWS OF AREA
STREAMS AND RIVERS...A HEIGHTENED THREAT OF MINOR FLOODING WILL
EXIST THROUGH TUESDAY. TUESDAY AND WEDNESDAY...NORTH CENTRAL IDAHO
AND WESTERN MONTANA WILL BE UNDER THE INFLUENCE OF HIGH PRESSURE.
TEMPERATURES ARE LIKELY TO RAPIDLY WARM TO SEASONAL AVERAGES.
HOWEVER...MODEL GUIDANCE HAS RECENTLY SUGGESTED THAT ANOTHER
PACIFIC STORM SYSTEM WILL DEVELOP OVER THE NORTHERN ROCKIES
WEDNESDAY AFTERNOON. AN UNSTABLE ATMOSPHERE WILL LIKELY EXIST
AHEAD OF THE ASSOCIATED SURFACE COLD FRONT...WITH SHOWER AND
THUNDERSTORM ACTIVITY ANTICIPATED. BY SATURDAY...THE STORM SYSTEM
IS EXPECTED TO MOVE EAST OF THE ROCKIES...WITH HIGH PRESSURE ONCE
AGAIN WARMING TEMPERATURES TO NEAR SEASONAL AVERAGES.

&&

.AVIATION...SCATTERED THUNDERSTORMS WILL CONTINUE TO DEVELOP THIS
AFTERNOON ACROSS THE ENTIRE REGION THROUGH THE EVENING HOURS. THE
MAIN THREAT OVER NORTHERN IDAHO AND NORTHWEST MONTANA WILL BE
HEAVY RAIN WITH SOME SMALL HAIL...WHILE FROM NEAR MISSOULA SOUTH
AND EAST THE ENVIRONMENT WILL BE CONDUCIVE TO LARGE HAIL AND
STRONG WIND GUSTS. THE CONVECTION WILL DIMINISH LATE TONIGHT...BUT
LARGE SCALE LIFT WILL CONTINUE WIDESPREAD RAIN INTO MONDAY MAINLY
OVER NORTHERN IDAHO AND NORTHWEST MONTANA. HEAVIER RAINFALL ACROSS
THE NORTHWEST... INCLUDING KGPI AND KMSO MAY BEGIN TO IMPACT
VISIBILITIES AFTER 21/0600Z. RAIN SHOWERS WILL LINGER BEFORE
DIMINISHING LATE MONDAY. EXPECT TERRAIN AND MOUNTAIN PASSES TO BE
OBSCURED AT TIMES FROM LOWERED CLOUDS AND SHOWERS.

&&

.HYDROLOGY...THERE IS THE CONTINUED CONCERN FOR FLOODING IMPACTS
RESULTING FROM MODERATE TO HEAVY DOWNPOURS ASSOCIATED WITH
THUNDERSTORMS THROUGH THIS EVENING ACROSS WESTERN
MONTANA AND CENTRAL IDAHO. SMALL STREAMS AND CREEKS COULD SEE
RAPID RISES IN WATER LEVELS...WITH MUD/DEBRIS FLOWS ALSO POSSIBLE.

AS THE LOW TREKS FURTHER NORTH AND EAST OVERNIGHT...AN AREA OF
WRAP-AROUND PRECIPITATION WILL KEEP CONTINUED MODERATE TO HEAVY
RAIN PERSISTING ALONG THE MONTANA/IDAHO BORDER THROUGH MONDAY
MORNING. THIS WILL ADD ADDITIONAL RAINFALL AMOUNTS TO ALREADY
SWOLLEN RIVERS AND STREAMS. RUNOFF FROM THIS WEATHER SYSTEM COULD
CONTRIBUTE TO FLOODING ISSUES WELL INTO TUESDAY. PLEASE STAY TUNED
TO UPDATES TO THE FORECAST AND FLOOD-RELATED HEADLINES AS THE
SYSTEM CONTINUES TO AFFECT THE REGION. WEATHER.GOV/MISSOULA

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
ID...NONE.
&&

SHORT TERM/HYDROLOGY...ALLEGRETTO
LONG TERM....ZUMPFE
AVIATION...NOLTE

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MISSOULA MT
1219 AM MDT SUN JUN 20 2010

IDZ009-010-MTZ005>007-043-202100-
WESTERN LEMHI COUNTY-EASTERN LEMHI COUNTY-
MISSOULA/BITTERROOT VALLEYS-BITTERROOT/SAPPHIRE MOUNTAINS-
BUTTE/BLACKFOOT REGION-POTOMAC/SEELEY LAKE REGION-
1219 AM MDT SUN JUN 20 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL
IDAHO AND WEST CENTRAL MONTANA.

.DAY ONE...TODAY AND TONIGHT

STRONG THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS THE AREA THIS
AFTERNOON AND EVENING. THE MAIN THREAT WILL BE WITH HEAVY RAIN AND
LARGE HAIL...BUT STRONG WIND GUSTS ARE ALSO POSSIBLE.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

SMALL STREAMS COULD RUN VERY HIGH MONDAY AND TUESDAY DUE TO THE
HEAVY RAIN SHOWERS. OTHERWISE THERE IS NO HAZARDOUS WEATHER
EXPECTED THROUGH THE COMING WEEK.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MISSOULA MT
101 PM MDT SUN JUN 20 2010

MTZ007-201945-
BUTTE/BLACKFOOT REGION-
101 PM MDT SUN JUN 20 2010

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN GRANITE AND NORTHERN
DEER LODGE COUNTIES UNTIL 145 PM MDT...

AT 1255 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING
A STRONG THUNDERSTORM 14 MILES WEST OF ANACONDA...MOVING EAST AT 15
MPH.

HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 40 MPH ARE
EXPECTED WITH THIS STORM.

LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE...WEST VALLEY AND LOST
CREEK.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF THREATENING WEATHER APPROACHES YOUR AREA...GO INDOORS AND STAY
AWAY FROM WINDOWS. IF YOU ARE CAUGHT OUTSIDE...MOVE TO A WELL
PROTECTED AREA.

&&

LAT...LON 4626 11291 4615 11288 4606 11329 4624 11336
TIME...MOT...LOC 1901Z 255DEG 12KT 4617 11320

ZUMPFE

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MISSOULA MT
208 PM MDT SUN JUN 20 2010

MTZ007-202100-
BUTTE/BLACKFOOT REGION-
208 PM MDT SUN JUN 20 2010

...SIGNIFICANT WEATHER ADVISORY FOR EASTERN DEER LODGE AND CENTRAL
SILVER BOW COUNTIES UNTIL 300 PM MDT...

AT 201 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM NEAR SILVER BOW...OR 8 MILES SOUTHWEST OF
BUTTE...MOVING NORTH AT 10 MPH.

HAIL UP TO THE SIZE OF PENNIES AND WIND GUSTS UP TO 40 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN.

LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE...SILVER BOW...GREGSON
HOT SPRINGS...WARM SPRINGS...NISSLER...RAMSAY...CRACKERVILLE AND
OPPORTUNITY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF THREATENING WEATHER APPROACHES YOUR AREA...GO INDOORS AND STAY
AWAY FROM WINDOWS. IF YOU ARE CAUGHT OUTSIDE...MOVE TO A WELL
PROTECTED AREA.

&&

LAT...LON 4618 11294 4624 11259 4589 11253 4585 11278
TIME...MOT...LOC 2008Z 168DEG 11KT 4596 11268

ZUMPFE