Flash Flood Warning 11, NWS Denver/Boulder, CO

171 
WGUS75 KBOU 202129
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
329 PM MDT SAT JUL 20 2013

COC069-202230-
/O.CON.KBOU.FF.W.0011.000000T0000Z-130720T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
LARIMER CO-
329 PM MDT SAT JUL 20 2013

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 430 PM MDT FOR
CENTRAL LARIMER COUNTY...

AT 326 PM MDT...DOPPLER RADAR INDICATED THUNDERSTORMS HAD MOVED 
SOUTHEAST OF THE HIGH PARK BURN AREA AS HEAVY RAIN HAD ENDED. UP TO 
ONE INCH OF RAIN MAY HAVE FALLEN OVER WESTERN PORTIONS OF THE HIGH 
PARK BURN AREA.

FLASH FLOODING WILL REMAIN OVER WESTERN PORTIONS OF THE HIGH PARK 
BURN AREA OF CENTRAL LARIMER COUNTY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

HEAVY RAINFALL WILL CAUSE FLASH FLOODING OF CREEKS...STREAMS...ROADS
AND CULVERTS IN THE HIGH PARK BURN AREA. SOME AREAS AFFECTED INCLUDE
RIST CANYON...BUCKHORN CREEK...REDSTONE CANYON...STOVE PRAIRIE...AND
GULCHES DRAINING INTO THE POUDRE CANYON ALONG HIGHWAY 14.  ROCK
SLIDES OR DEBRIS FLOWS CAN ALSO BE EXPECTED ACROSS ROADS IN THE BURN
AREA.

MOVE TO HIGHER GROUND NOW. ACT QUICKLY TO PROTECT YOUR LIFE.

&&

LAT...LON 4072 10538 4057 10536 4057 10554 4072 10552

$$

RPK

205 
WGUS75 KBOU 202228
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
428 PM MDT SAT JUL 20 2013

COC069-202237-
/O.EXP.KBOU.FF.W.0011.000000T0000Z-130720T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
LARIMER CO-
428 PM MDT SAT JUL 20 2013

...THE FLASH FLOOD WARNING FOR CENTRAL LARIMER COUNTY WILL EXPIRE AT
430 PM MDT...

THE HEAVY RAIN HAS ENDED...AND FLOODING IS NO LONGER EXPECTED TO POSE
A THREAT.

LAT...LON 4072 10538 4057 10536 4057 10554 4072 10552

$$

RPK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
1148 AM MDT SAT JUL 20 2013

.UPDATE...

&&

.SHORT TERM...EVENTS UNFOLDING ABOUT AS EXPECTED. WEAK SHORTWAVE
DRAGGING ACROSS SOUTH DAKOTA AND WESTERN NEBRASKA...PROBABLY SOME
WEAK UPWARD FORCING MOVING ACROSS NORTHEASTERN COLORADO THIS
AFTERNOON. DRIER AIR ALOFT BUT SHALLOW RICH MOISTURE WITH WEAK
EASTERLY WINDS DEVELOPING ON THE PLAINS FROM BOTH DIURNAL TENDENCY
AND PRESSURE SURGE ASSOCIATED WITH THE SHORTWAVE. SURFACE
MOISTURE ALONG THE FRONT RANGE SHOULD MIX OUT SOMEWHAT. FURTHER
EAST IT WILL PROBABLY TAKE UNTIL LATE AFTERNOON TO BREAK THE LOW
LEVEL INVERSION...AND IT MAY TAKE OUTFLOW BOUNDARIES FROM EITHER
BETTER ORGANIZED CONVECTION TO THE NORTH OR FROM MOUNTAIN
CONVECTION TO GET THINGS GOING. FORECAST CAPES AROUND 500 J/KG
NEAR THE MOUNTAINS AND 1500-2000 J/KG ON THE PLAINS AND JUST
ENOUGH SHEAR TO SUPPORT TILTED UPDRAFTS STILL LOOK GOOD...SO
SLIGHT RISK IN THE CORNER SEEMS APPROPRIATE WITH THE MAIN THREAT
IN THE EARLY EVENING. WITH STORM MOTIONS OF AT LEAST 15
KNOTS...FLOOD THREAT MUCH LOWER TODAY...COULD SEE MINOR FLOODING
WITH THE STRONGEST STORMS OR IF A BURN AREA GETS HIT JUST RIGHT
BUT ODDS ARE SMALL.

&&

.AVIATION...VFR CONDITIONS THROUGH TONIGHT. SCATTERED
THUNDERSTORMS OVER THE MOUNTAINS SHOULD WEAKEN AS THEY MOVE EAST
IN THE LATE AFTERNOON...OUTFLOW WINDS MAY MAKE CONVECTION SKIP
OVER THE DENVER AREA. AT THIS TIME THE THREAT IS TOO LOW TO
MENTION IN THE KDEN/KAPA TAFS THOUGH THERE IS STILL A CHANCE OF
OUTFLOW WINDS AFFECTING OPERATIONS IN THE 21Z-03Z TIME FRAME.

&&

.PREV DISCUSSION... /ISSUED 406 AM MDT SAT JUL 20 2013/

SHORT TERM...YESTERDAYS MCV WAS THE BIG WEATHER PLAYER WHICH
BROUGHT HEAVY RAINFALL TO PORTIONS OF THE NORTHEAST PLAINS AND
TOO MUCH SUBSIDENCE FOR STORM DEVELOPMENT IN/NEAR THE FOOTHILLS.
THAT SYSTEM HAS PUSHED WELL AWAY FROM THE AREA...SO AIRMASS WILL
HAVE A CHANCE TO RESET.

OTHER THAN SOME PATCHY FOG OVER THE NORTHEAST CORNER...WE WILL
START THE DAY WITH DRY AND MAINLY SUNNY WEATHER. BY
AFTERNOON...THE AIRMASS DESTABILIZES SUFFICIENTLY TO BRING A
CHANCE OF THUNDERSTORMS TO THE FRONT RANGE MOUNTAINS/FOOTHILLS BY
EARLY AFTERNOON AND THEN OVER THE NORTHEAST PLAINS AFTER 2-3 PM.
CONVECTIVE INHIBITION GRADUALLY WEAKENS THROUGH THE AFTERNOON AND
CAPES WILL BE BUILDING OVER THE NORTHEAST PLAINS WHERE LOW LEVEL
MOISTURE HOLDS IN PLACE. LOOK FOR CLOSE TO 2000 J/KG AND
SUFFICIENT 0-6KM BULK SHEAR OF 30-35 KTS FOR POTENTIAL OF A FEW
SEVERE STORMS. THERE IS STILL A WEAK CAP IN PLACE SO MAY HAVE TO
WAIT FOR STORMS TO ORIGINATE IN WYOMING AND NEBRASKA PANHANDLE AND
MOVE SOUTHEAST BEFORE OUR CAPES ARE REALIZED. SPC HAS FAR
NORTHEAST CORNER HIGHLIGHTED BUT SEE THREAT AS FAR WEST AS
MORGAN/EASTERN WELD COUNTIES WITH LOW LEVEL MOISTURE EXPECTED TO
HOLD THERE THANKS TO EAST/SOUTHEAST WINDS. FARTHER WEST IN THE
I-25 CORRIDOR...CAPES WILL MOST LIKELY DROP TO LESS THAN 500 J/KG
AS LOW LEVEL MOISTURE DECREASES THROUGH THE AFTERNOON SO AT THIS
TIME MAIN THREAT ALONG THE FRONT RANGE LOOKS TO BE GUSTY OUTFLOW
WINDS FROM STORMS.

LOOK FOR A DECREASE IN STORMS LATE THIS EVENING WITH WARMING AND
DRYING ALOFT. CLEARING SKIES AND MILD TEMPS OVERNIGHT.

LONG TERM...AN UPPER RIDGE BUILDING INTO THE AREA WILL BRING
NORTHWESTERLY FLOW ALOFT ALONG WITH WARMER AND DRIER CONDITIONS
SUNDAY INTO TUESDAY. THERE WILL BE A SLIGHT CHANCE OF SEEING A FEW
SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS EACH DAY AS WELL AS
OVER THE FAR EASTERN PLAINS AS A FEW WEAK DISTURBANCES MOVE BY.
TEMPERATURES WILL BE ABOVE NORMAL WITH READINGS IN THE LOW TO MID
90S OVER THE PLAINS AND IN THE 70S AND LOW 80S IN THE MOUNTAINS.
MINIMUM HUMIDITIES WILL BE DROPPING INTO THE LOW TEENS HOWEVER
WIND SPEEDS ARE EXPECTED TO STAY BELOW CRITERIA.

ON WEDNESDAY...THE UPPER LOW CURRENTLY OVER THE BAJA WILL CIRCLE
NORTH ALONG THE CA COAST THEN COME INLAND AGAIN. MOISTURE FROM
THIS LOW WILL BEGIN SPREADING OVER THE STATE FOR A SLIGHT BUMP UP
IN CHANCES FOR STORMS. COOLER AIR IS PROGGED ALSO TO MOVE IN AS
HEIGHTS LOWER AND A COLD FRONT IS PUSHED SOUTH ACROSS THE AREA.
WITH MORE MOISTURE AVAILABLE THURSDAY...A BETTER CHANCE FOR
PRECIPITATION WILL OCCUR. ANOTHER FRONT IS PROGGED TO MOVE IN
FRIDAY AS THE UPPER LOW MOVES EAST AND DROPS INTO THE GREAT
PLAINS WITH HIGH SURFACE PRESSURE PUSHING IN FROM THE NORTHERN
GREAT PLAINS. EXPECT SHOWERS AND THUNDERSTORMS TO BECOME MORE
WIDESPREAD WITH GOOD CHANCES FOR MEASURABLE PRECIPITATION AND
TEMPERATURES TO BE BACK TOWARDS NORMAL FOR LATE JULY.

AVIATION...SCATTERED AFTERNOON/EVENING STORMS MAY AFFECT THE
FRONT RANGE AIRPORTS WITH THE MAIN CHANCE FROM 22Z-03Z. PROB30 OF
THUNDER AND GUSTY OUTFLOW WINDS IS REASONABLE AT THIS TIME.
OTHERWISE LOOK FOR VFR CONDITIONS AND FAIRLY NORMAL DIURNAL WIND
PATTERNS.

HYDROLOGY...STORMS WILL BE FASTER MOVING NEAR 20-25 MPH AND THERE
IS LESS PRECIPITABLE WATER...NEAR 0.80 INCH...ALONG THE FRONT
RANGE TODAY. BURN SCARS WOULD ONLY HAVE LOW POTENTIAL FOR ANY
FLOODING WITH MOST STRONGER STORMS ALONG THE FRONT RANGE PRODUCING
0.50 INCH OR LESS IN 20 MINUTES.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

SHORT TERM...BARJENBRUCH
LONG TERM....KRIEDERMAN
AVIATION/UPDATE...GIMMESTAD

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
1107 AM MDT SAT JUL 20 2013

COZ030>051-211715-
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-
1106 AM MDT SAT JUL 20 2013

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

.DAY ONE...TODAY AND TONIGHT

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER NORTHEASTERN
COLORADO THIS AFTERNOON AND EVENING...GENERALLY EAST OF
BRIGGSDALE...FORT MORGAN...AND LIMON. THE MAIN THREATS FROM THE
THUNDERSTORMS WILL BE LARGE HAIL AND DAMAGING WINDS. SCATTERED
THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON AND MOVE
SOUTHEASTWARD. IN AREAS FURTHER WEST THERE WILL STILL BE SOME
THUNDERSTORMS BUT WITH LESS MOISTURE THE STORMS WILL BE LESS
NUMEROUS AND LESS INTENSE. THUNDERSTORMS WILL END IN THE WESTERN
PART OF THE AREA THIS EVENING...BUT THERE IS STILL A SLIGHT CHANCE
OF STORMS IN THE NORTHEAST CORNER OVERNIGHT.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THERE WILL BE A SLIGHT CHANCE OF THUNDERSTORMS OVER THE HIGH
COUNTRY AND THE FAR NORTHEASTERN PLAINS SUNDAY THROUGH TUESDAY.
SUNDAYS STORMS OVER THE FAR EASTERN PLAINS MAY CONTAIN HAIL AND
GUSTY WINDS. THE CHANCES FOR STORMS WILL INCREASE EACH DAY
WEDNESDAY THROUGH FRIDAY ACROSS THE ENTIRE FORECAST AREA AS
SUBTROPICAL MOISTURE MOVES INTO THE STATE.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED IN THE NORTHEAST CORNER OF
COLORADO AFTER 3 PM.

GIMMESTAD/COOPER