Severe Thunderstorm Warning 91, NWS Denver/Boulder, CO

132 
WWUS55 KBOU 302251
SVSBOU

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
451 PM MDT THU JUN 30 2011

COC049-117-302301-
/O.EXP.KBOU.SV.W.0091.000000T0000Z-110630T2300Z/
SUMMIT CO-GRAND CO-
451 PM MDT THU JUN 30 2011

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN GRAND AND
NORTHWESTERN SUMMIT COUNTIES WILL EXPIRE AT 500 PM MDT...

THE THUNDERSTORM THAT PROMPTED THE WARNING HAS EXITED THE AREA.

LAT...LON 4024 10659 4016 10581 3983 10582 3972 10632
      3975 10633 3975 10636 3976 10637 3982 10640
      3986 10643 3988 10642 3992 10644 3993 10663
      4000 10664
TIME...MOT...LOC 2251Z 237DEG 39KT 4011 10587

$$

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
306 PM MDT THU JUN 30 2011

.SHORT TERM...THE SLOWER ARRIVAL OF THE UPPER LEVEL TROUGH WILL
CONTINUE TO KEEP UPWARD Q-G LIFT AND A FAVORABLE ENVIRONMENT FOR
SHOWERS AND STORMS THROUGH THE EVENING.  THERE IS STILL A THREAT OF
SEVERE STORMS WITH DAMAGING WINDS GIVEN DOWNDRAFT CAPES OF 500-1200
J/KG...FLOW ALOFT INCREASING TO 30-40 KNOTS IN THE 700-600 MB
LEVEL...AND DRY SUBCLOUD LAYER AIDING EVAPORATIVE COOLING AND
DOWNBURSTS. THE THREAT OF THE STRONGEST DOWNBURSTS WILL OCCUR IN THE
MOST UNSTABLE AIRMASS OVER THE EASTERN PLAINS...BUT THE ORGANIZED
LINE OF CONVECTION NOW MOVING INTO THE CENTRAL PORTIONS OF COLORADO
WILL HAVE HAVE A POTENTIAL TO PRODUCE WIND GUSTS IN EXCESS OF 50
KNOTS.  THAT LINE IS DUE TO REACH THE I-25 URBAN CORRIDOR BY 23Z-00Z.

CONVECTIVE COVERAGE AS WELL AS SEVERE THREAT SHOULD GRADUALLY
DECREASE LATER THIS EVENING AS AIRMASS STABILIZES AND UPPER LEVEL
SUPPORT SLOWLY WEAKENS.  AFTER MIDNIGHT...ANY STORMS SHOULD BE
CONFINED TO THE FAR NORTHEAST CORNER OF THE STATE.

TEMPERATURES HAVE COOLED AND AIRMASS HAS MOISTENED SUFFICIENTLY TO
CANCEL THE RED FLAG WARNING IN THE FOOTHILLS...SOUTH PARK...AND
PALMER DIVIDE.  WILL ONLY ALLOW THE WARNINGS IN LINCOLN AND
WASHINGTON COUNTIES TO CONTINUE TIL 9 PM AS VERY WARM READINGS WITH
POTENTIAL FOR NEW FIRES FROM LIGHTNING STRIKES CONTINUES THERE.

.LONG TERM...A TYPICAL MID-SUMMER UPPER AIR PATTERN IS EXPECTED TO
BUILD OVER THE SOUTHWESTERN U.S. AFTER TONIGHT/S UPPER DISTURBANCE
MOVES OUT OF THE STATE.  INITIALLY...MODERATE WESTERLY FLOW ALOFT
WILL BE OVER THE STATE ON THE WESTERN EDGE OF THE SUBTROPICAL RIDGE
ACROSS THE SOUTHERN HALF OF THE COUNTRY.  MOISTURE LEVELS MAY BE
SUPPRESSED SOMEWHAT BY THE SUBSIDENCE OF RISING HEIGHTS...BUT ENOUGH
MOISTURE MAY REMAIN IN PLACE TO FUEL A ROUND OF AFTERNOON SHOWERS.
THE NAM LOW LEVEL WINDS ALSO SHOW EASTERLY FLOW ACROSS THE PLAINS
WHICH WOULD KEEP MOISTURE FROM FLUSHING OUT OF THE AREA.  LOW POPS
IN THE FORECAST FOR THE AFTERNOON AND EVENING LOOK TO BE WARRANTED.
BY SATURDAY...SOME MOISTURE LEFT OVER FROM TROPICAL STORM ARLENE MAY
BE ENTRAINED INTO THE CIRCULATION AROUND THE SUBTROPICAL RIDGE.

THE REST OF THE FORECAST PERIOD LOOKS LIKE THE UPPER RIDGE AND WARM
TEMPERATURES REMAIN OVER THE SOUTHWESTERN U.S.  MID AND UPPER LEVEL
MOISTURE FROM THE GULF OF MEXICO OR AN EARLY MONSOON MAY EVENTUALLY
ENTRAIN INTO THE WEAK FLOW ASSOCIATED WITH THE UPPER RIDGE.
THEREFORE...LOW POPS WILL REMAIN IN THE FORECAST THROUGH THE LATTER
PART OF NEXT WEEK.  TEMPERATURES ARE EXPECTED TO BE AT OR ABOVE
SEASONAL NORMALS...WITH MONDAY POSSIBLY BEING THE WARMEST DAY OF THE
LOT.  MOS GUIDANCE HAS THE LOWEST POPS CONTINUING THROUGH THE
WEEKEND WHICH WOULD ALLOW TEMPERATURES TO WARM TO THE MID OR UPPER
90S.  HOWEVER...IF MORE MOISTURE BEGINS MOVING OVER THE STATE THEN
AFTERNOON HIGHS MIGHT TOP OUT CLOSER TO THE 90 DEGREE MARK EACH
DAY.  LATE IN THE FORECAST PERIOD...MOS POP GUIDANCE BEGINS
INCREASING WHICH WOULD SUPPORT THE IDEA OF THE ONSET OF THE SEASONAL
MONSOON.  AS THE MOISTURE BEGINS INCREASING OVER THE STATE AND WIND
PATTERNS ALOFT WEAKEN...THE THREAT FOR HEAVY RAINFALL FROM SLOW
MOVING SHOWERS WILL INCREASE.  THESE DETAILS CAN BE ADDRESSED EARLY
NEXT WEEK.

&&

.AVIATION...GUSTY AND VARIABLE WINDS TO AROUND 45 KNOTS STILL
EXPECTED WITH STORMS TIL EARLY EVENING WITH BRIEF SHUTOFFS POSSIBLE
AT LOCAL AIRPORTS.  ONE ORGANIZED BAND SHOULD REACH THE FRONT RANGE
AIRPORTS 23Z-00Z...WITH A DECREASE OF CONVECTION BEHIND THAT.  STILL
CANT RULE OUT GUSTY WINDS TO 30-40 KNOTS FROM 00Z-04Z GIVEN THE
STRONG MID LEVEL FLOW...BUT OVERALL CONDITIONS SHOULD IMPROVE AFTER
00Z.  OTHERWISE...VFR CONDITIONS WILL PREVAIL.  NO THUNDERSTORMS
EXPECTED FROM 06Z THROUGH AT LEAST 23Z TOMORROW AFTERNOON WITH DRIER
AIRMASS TAKING HOLD.

&&

.HYDROLOGY...MORE NUMEROUS SHOWERS AND STORMS EXPECTED THROUGH
EARLY THIS EVENING.  WIDESPREAD 0.25 INCH AMOUNTS IN THE
MOUNTAINS...BUT LOCALLY 0.50 TO 1.0 INCH AMOUNTS EXPECTED WITH
STRONGER STORMS. THOSE AMOUNTS WOULD NOT CAUSE MUCH RISE IN STREAM
LEVELS OUTSIDE OF THE SNOWMELT.  EAST OF THE FRONT RANGE
MOUNTAINS...PRECIPITATION AMOUNTS SHOULD MOSTLY BE UNDER A QUARTER
INCH...BUT STILL A CHANCE OF 0.50 INCH FROM STRONGER STORMS OVER THE
PLAINS AND FOOTHILLS. WITH THOSE RAINFALL AMOUNTS...THREAT OF ANY
FLOODING ISSUES INCLUDING THE FOURMILE BURN AREA IS LOW.

FLOOD ADVISORIES...

 BIG THOMPSON RIVER THROUGH ESTES PARK UNTIL NOON SATURDAY.
 CACHE LA POUDRE RIVER AT THE CANYON MOUTH UNTIL SATURDAY
  AFTERNOON.
 COLORADO RIVER NEAR GRANBY UNTIL SATURDAY AFTERNOON.
 COLORADO RIVER NEAR KREMMLING UNTIL SATURDAY AFTERNOON.
 ST LOUIS CREEK IN SOUTHWEST GRAND COUNTY UNTIL SATURDAY
  AFTERNOON.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...RED FLAG WARNING FOR LINCOLN AND
  WASHINGTON COUNTIES UNTIL 9 PM MDT...FIRE WEATHER ZONES 246..247..
  AND 249.

&&

BARJENBRUCH/KDRBY

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DENVER CO
1115 AM MDT THU JUN 30 2011

COZ030>051-011200-
JACKSON COUNTY BELOW 9000 FEET-WEST JACKSON AND WEST GRAND
COUNTIES ABOVE 9000 FEET-GRAND AND SUMMIT COUNTIES BELOW 9000
FEET-SOUTH AND EAST JACKSON/LARIMER/NORTH AND NORTHEAST GRAND/
NORTHWEST BOULDER COUNTIES ABOVE 9000 FEET-SOUTH AND SOUTHEAST
GRAND/WEST CENTRAL AND SOUTHWEST BOULDER/GILPIN/CLEAR CREEK/
SUMMIT/NORTH AND WEST PARK COUNTIES ABOVE 9000 FEET-LARIMER AND
BOULDER COUNTIES BETWEEN 6000 AND 9000 FEET-JEFFERSON AND WEST
DOUGLAS COUNTIES ABOVE 6000 FEET/GILPIN/CLEAR CREEK/NORTHEAST PARK
COUNTIES BELOW 9000 FEET-CENTRAL AND SOUTHEAST PARK COUNTY-LARIMER
COUNTY BELOW 6000 FEET/NORTHWEST WELD COUNTY-BOULDER AND JEFFERSON
COUNTIES BELOW 6000 FEET/WEST BROOMFIELD COUNTY-NORTH DOUGLAS
COUNTY BELOW 6000 FEET/DENVER/WEST ADAMS AND ARAPAHOE COUNTIES/
EAST BROOMFIELD COUNTY-ELBERT/CENTRAL AND EAST DOUGLAS COUNTIES
ABOVE 6000 FEET-NORTHEAST WELD COUNTY-CENTRAL AND SOUTH WELD
COUNTY-MORGAN COUNTY-CENTRAL AND EAST ADAMS AND ARAPAHOE COUNTIES-
NORTH AND NORTHEAST ELBERT COUNTY BELOW 6000 FEET/NORTH LINCOLN
COUNTY-SOUTHEAST ELBERT COUNTY BELOW 6000 FEET/SOUTH LINCOLN
COUNTY-LOGAN COUNTY-WASHINGTON COUNTY-SEDGWICK COUNTY-PHILLIPS
COUNTY-
1115 AM MDT THU JUN 30 2011

...RED FLAG WARNING FOR THE FRONT RANGE FOOTHILLS...PARK
COUNTY...AND PALMER DIVIDE EASTWARD THROUGH LINCOLN AND WASHINGTON
COUNTIES UNTIL 9 PM MDT THIS EVENING...

...STRONG AND POSSIBLY SEVERE THUNDERSTORMS EXPECTED TO MOVE OVER
THE MOUNTAINS AND URBAN CORRIDOR THIS AFTERNOON...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL
COLORADO.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS WITH STRONG AND POTENTIALLY DAMAGING WINDS CAN BE
EXPECTED ACROSS NORTHEAST AND NORTH CENTRAL COLORADO THIS AFTERNOON
INTO EARLY THIS EVENING.  NUMEROUS THUNDERSTORMS WILL DEVELOP IN THE
MOUNTAINS AND SPREAD NORTHEAST ACROSS THE PLAINS THIS AFTERNOON. THE
COMBINATION OF STRONG WINDS IN THE UPPER LEVELS OF THE ATMOSPHERE
ALONG WITH RELATIVELY DRY LOW LEVELS WILL ALLOW STORMS TO PRODUCE
THE STRONG AND GUSTY WINDS.  DAMAGING WIND GUSTS UP TO 70 MPH WILL
BE POSSIBLE.  THERE IS ALSO POTENTIAL FOR HEAVY RAINFALL WITH
AMOUNTS UP TO 1 INCH FROM THE STRONGER STORMS MAINLY ALONG AND WEST
OF THE FRONT RANGE MOUNTAINS.

THERE WILL BE HIGH FIRE DANGER THIS AFTERNOON AND EVENING ACROSS THE
FRONT RANGE FOOTHILLS...PARK COUNTY...AND PALMER DIVIDE AREA WITH
STRONG AND GUSTY SOUTHWEST WINDS...LOW HUMIDITIES AND LIGHTNING WITH
THE STORMS.

THE INCREASE IN STORMS TODAY IS DUE TO AN APPROACHING UPPER LEVEL
DISTURBANCE MOVING FROM EASTERN UTAH INTO WESTERN COLORADO.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THERE WILL BE A SLIGHT CHANCE OF THUNDERSTORMS ON SATURDAY AFTERNOON
AND EVENING WITH ACTIVITY BECOMING MORE ISOLATED FOR SUNDAY AND THE
4TH OF JULY.  TEMPERATURES WILL BE ABOVE NORMAL SATURDAY THROUGH
MONDAY.  FOR TUESDAY AND WEDNESDAY...SUBTROPICAL MOISTURE COMBINED
WITH A WEAK COLD FRONT MAY LEAD TO A BETTER CHANCE OF THUNDERSTORMS
ALONG WITH SLIGHTLY COOLER TEMPERATURES.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL LIKELY BE REQUIRED BY 1 PM FOR REPORTING
STRONG AND DAMAGING WIND GUSTS.

BARJENBRUCH/DANKERS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DENVER CO
1216 PM MDT THU JUN 30 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1214 PM     TSTM WND GST     3 SE DENVER INTL AIRPOR 39.83N 104.63W
06/30/2011  M58.00 MPH       DENVER             CO   MESONET

&&

JK

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE DENVER CO
1227 PM MDT THU JUN 30 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1217 PM     TSTM WND GST     7 SE DENVER INTL AIRPOR 39.79N 104.58W
06/30/2011  M63.00 MPH       ADAMS              CO   AWOS

1214 PM     TSTM WND GST     3 SE DENVER INTL AIRPOR 39.83N 104.63W
06/30/2011  M63.00 MPH       DENVER             CO   MESONET

&&

JK

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
1238 PM MDT THU JUN 30 2011

COZ040-043-045-301900-
CENTRAL AND SOUTH WELD COUNTY CO-
CENTRAL AND EAST ADAMS AND ARAPAHOE COUNTIES CO-
NORTH DOUGLAS COUNTY BELOW 6000 FEET/DENVER/WEST ADAMS AND ARAPAHOE
COUNTIES/EAST BROOMFIELD COUNTY CO-
1238 PM MDT THU JUN 30 2011

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A SIGNIFICANT
WEATHER ADVISORY FOR

  NORTH CENTRAL ADAMS COUNTY
  SOUTH CENTRAL WELD COUNTY

AT 1237 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
THUNDERSTORM CAPABLE OF PRODUCING WIND GUSTS TO AROUND 50 MPH.  THIS
STORM WAS LOCATED 11 MILES SOUTH OF PROSPECT VALLEY...OR 29 MILES
NORTHEAST OF DENVER...MOVING NORTHEAST AT 25 MPH.

LOCATIONS IN THE ADVISORY INCLUDE BUT ARE NOT LIMITED TO ROGGEN AND
PROSPECT VALLEY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THE WINDS MAY BE STRONG ENOUGH TO BLOW AROUND LOOSE OBJECTS SUCH AS
OUTDOOR PATIO FURNITURE AND TRASH CANS. BRIEF HEAVY RAIN CAN ALSO BE
EXPECTED.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM MDT
THURSDAY EVENING FOR NORTHEASTERN COLORADO.

&&

LAT...LON 4021 10416 3989 10427 3989 10459 4023 10446
TIME...MOT...LOC 1837Z 210DEG 34KT 3996 10446

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE DENVER CO
357 PM MDT THU JUN 30 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0343 PM     TSTM WND GST     2 S WILLARD             40.52N 103.48W
06/30/2011  E70.00 MPH       MORGAN             CO   TRAINED SPOTTER

1217 PM     TSTM WND GST     7 SE DENVER INTL AIRPOR 39.79N 104.58W
06/30/2011  M63.00 MPH       ADAMS              CO   AWOS

1214 PM     TSTM WND GST     3 SE DENVER INTL AIRPOR 39.83N 104.63W
06/30/2011  M63.00 MPH       DENVER             CO   MESONET

&&

FREDIN