River Flood Advisory 4, NWS Denver/Boulder, CO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
924 PM MDT SUN MAY 25 2014

.UPDATE...
ISSUED AT 858 PM MDT SUN MAY 25 2014

SHOWER AND THUNDERSTORM ACTIVITY HAS RAPIDLY DIMINISHED OVER MUCH
OF THE CWA THIS EVENING. THE EXCEPTION IS OVER LINCOLN AND EASTERN
ELBERT COUNTIES WHERE ACTIVITY HAS INCREASED AGAIN AS WEAK IMPULSE
IS ROTATING AROUND THE UPPER LOW OVER FAR NORTHERN NEW MEXICO.
CAN'T RULE OUT SOME CONTINUED SHOWER ACTIVITY THRU MUCH OF THE
NIGHT ESPECIALLY OVER SOUTHEAST PORTIONS OF CWA. WILL UPDATE ZONES
TO FAVOR THESE AREAS.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 155 PM MDT SUN MAY 25 2014

UPPER LEVEL LOW OVER SOUTHWEST COLORADO WILL SLOWLY DRIFT SOUTHEAST
TONIGHT AND MONDAY. SOUTHERLY FLOW ALOFT AHEAD OF IT HAS BROUGHT
DRIER AIR TO EASTERN COLORADO. ALONG THE FRONT RANGE...THE AIRMASS
REMAINS MOIST WHERE PRECIPITABLE WATER VALUES ARE AROUND THREE
QUARTERS OF AN INCH. CAPES ARE UP TO 2000 J/KG ALONG THE FRONT
RANGE...BUT LESS THAN 500 J/KG OVER SOUTHEASTERN COLORADO. ALREADY
SEEING A GOOD NUMBER OF STORMS FORMING OVER THE FOOTHILLS AND MOVING
WEST. EXPECT ADDITIONAL DEVELOPMENT THROUGH EARLY EVENING OVER THE
MOUNTAINS...FOOTHILLS AND FRONT RANGE. WILL HAVE HIGHEST POPS
THROUGH THE EARLY EVENING HOURS FOR THE FOOTHILLS AND AREAS NEAR BY.
THE DRIER AIR OVER THE PLAINS WILL LIMIT CONVECTION AND WILL JUST
HAVE ISOLATED POPS. EVEN THOUGH SHEAR IS WEAK...WITH CAPES UP TO
2000 J/KG...COULD SEE A BRIEF SEVERE STORM WITH HAIL UP TO ONE INCH.
IF STORMS PERSIST OVER AN AREA...FLASH FLOODING WILL BE POSSIBLE.
STORMS ARE EXPECTED TO DECREASE BY MID EVENING AS THE AIRMASS
STABILIZES. WILL KEEP LOW POPS IN THROUGH THE NIGHT WITH THE UPPER
LEVEL LOW NEAR BY...BUT MOST LOCATIONS SHOULD STAY DRY.

AIRMASS WARMS TOMORROW AS THE LOW DIPS SOUTH. HIGHS WILL CLIMB INTO
THE 70S ACROSS NORTHEAST COLORADO. MOISTURE AND INSTABILITY
DECREASE...BUT ENOUGH WILL PREVAIL FOR ISOLATED TO SCATTERED
AFTERNOON STORMS. COVERAGE WILL BE LESS AND THAN TODAY. THREAT FOR
SEVERE STORMS AND FLASH FLOODING WILL BE LOWER TOO.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 341 PM MDT SUN MAY 25 2014

LITTLE CHANGE IN FORECAST THINKING FOR THE WEEK AHEAD. AFTER THE
UPPER LOW FINALLY MOVES TO THE SOUTHERN PLAINS MONDAY NIGHT...AN
UPPER RIDGE WILL BUILD OVER THE DESERT SOUTHWEST AND COLORADO.
FLOW ALOFT WILL BECOME MORE WESTERLY AND WARMER TEMPERATURES ALOFT
WILL BRING SOME STABILITZATION TO THE ATMOSPHERE. MORE BENIGN
WEATHER SHOULD PREVAIL FOR THE TUESDAY THROUGH THURSDAY TIME
FRAME. TEMPERATURES WILL ALSO WARM TO ABOVE SEASONAL
NORMALS...INTO THE MID 80S ACROSS THE PLAINS. THIS MAY LEAD TO A
SLIGHT RISE IN THE SNOWMELT RUNOFF. FOR THE END OF THE WEEK...IT
LOOKS LIKE A RETURN TO DEEP SOUTHERLY FLOW ALOFT AS AN UPPER
TROUGH DEVELOPS OVER THE WEST COAST. THE SOUTHERLY FLOW WILL
TRANSPORT BOTH GULF OF MEXICO AND EASTERN PACIFIC MOISTURE ACROSS
NEW MEXICO AND COLORADO. WILL BE KEEPING AN EYE ON THE REMNANTS OF
HURRICANE AMANDA THROUGH THE WEEK TO SEE IF MOISTURE FROM THAT
STORM GETS DRAWN INTO THE EASTERN PACIFIC MOISTURE FLOW. FOR NOW
HAVE POPS INCREASING FOR FRIDAY AND SATURDAY ALONG WITH COOLER
TEMPERATURES...AT LEAST PARTLY DUE TO THE ANTICIPATED INCREASE IN
CLOUD COVER THROUGH NEXT WEEKEND.

&&

.AVIATION...(FOR THE TAFS THROUGH 06Z MONDAY EVENING)
ISSUED AT 858 PM MDT SUN MAY 25 2014

WITH SURFACE LOW OVER SOUTHEAST COLORADO MAY CONTINUE TO SEE SOME
LIGHT WEST TO NORTHWEST WINDS WRAPPING AROUND THE SURFACE LOW.
CHANCES OF ANY SHOWERS LOOKS REMOTE HOWEVER WILL MONITOR ACTIVITY
OVER ELBERT AND LINCOLN IN CASE THOSE SHOWERS MOVE FAR ENOUGH TO
THE NORTHWEST.

&&

.HYDROLOGY...
ISSUED AT 858 PM MDT SUN MAY 25 2014

RIVERS AND STREAMS CONTINUE TO RISE TODAY DUE TO SNOWMELT AND
RECENT RAINFALL. THE DIMINISHED RAINFALL THIS EVENING SHOULD KEEP
RIVERS FROM RISING TO QUICKLY OVERNIGHT. MAIN CONCERNS ARE ON THE
CACHE LA POUDRE NEAR GREELEY WITH SOME MINOR FLOODING ALREADY
REPORTED. OTHER AREAS OF CONCERN ARE OVER THE RIVERS/STREAMS
ACROSS JACKSON AND GRAND COUNTIES. THE MICHIGAN RIVER REMAINS
RIGHT AT FLOOD STAGE THIS EVENING.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
.FLOOD WARNING... CACHE LA POUDRE NEAR GREELEY UNTIL 5/28@1500Z.
.FLOOD WARNING... MICHIGAN RIVER IN JACKSON CO. UNTIL 5/26@115Z.
.FLOOD ADVISORY...CACHE LA POUDRE@CANYON MOUTH IN LARIMER CO UNTIL
5/26@2215Z.
.AREAL FLOOD ADVISORY...GRAND AND JACKSON COUNTIES UNTIL
5/27@1530Z.

&&

UPDATE...ENTREKIN
SHORT TERM...MEIER
LONG TERM...DANKERS
AVIATION...ENTREKIN
HYDROLOGY...ENTREKIN

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
618 PM MDT SUN MAY 25 2014

COZ030>051-270030-
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-
618 PM MDT SUN MAY 25 2014

...BIG PACIFIC STORM SYSTEM IS FINALLY LOSING ITS GRIP ON
NORTHEAST COLORADO...

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

.DAY ONE...TONIGHT

LATE THIS AFTERNOON...DRIER AND MORE STABLE AIR SPREAD OVER MUCH
OF THE OUTLOOK AREA...RESULTING IN A SIGNIFICANT DECREASE IN
SHOWER AND THUNDERSTORM ACTIVITY. THE FEW REMAINING THUNDERSTORMS
OVER THE NORTHERN FRONT RANGE AND EASTERN PORTIONS LARIMER COUNTY
SHOULD DISSIPATE OR MOVE OUT OF THE AREA BY AROUND 8 PM. THESE
STORMS MAY STILL PRODUCE RAINFALL AMOUNTS UP TO ONE-HALF INCH...
WIND GUSTS TO AROUND 35 MPH AND POSSIBLY SOME SMALL HAIL. A FEW
WEAK THUNDERSTORMS MAY ALSO FORM ALONG A WIND GUST FRONT MOVING
EAST ACROSS THE NORTHEAST PLAINS EARLY THIS EVENING. LITTLE
RAINFALL IS EXPECTED FROM THESE STORMS.

THEREFORE...THE RISK OF FLASH FLOODING AS THE RESULT OF HEAVY
RAINFALL HAS ENDED.

OVERNIGHT...MOUNTAIN AREAS ROUGHLY ABOVE 10 THOUSAND FEET COULD
SEE A FEW INCHES OF SNOW BY MORNING.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

ON MONDAY...WRAP-AROUND MOISTURE FROM THE DEPARTING STORM SYSTEM
WILL BRING ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS TO THE
FRONT RANGE FOOTHILLS AND I-25 CORRIDOR. DRIER CONDITIONS CAN BE
EXPECTED FROM TUESDAY THROUGH FRIDAY AS UPPER LEVEL HIGH PRESSURE
AND A DRIER AIRMASS MOVE OVER COLORADO. MOISTURE WILL INCREASE
AGAIN LATER FRIDAY AND SATURDAY WITH INCREASING CHANCES OF SHOWERS
AND THUNDERSTORMS AT THAT TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT BUT
RAINFALL REPORTS WILL BE APPRECIATED.

BAKER/DANKERS