Heavy Rain in Colorado, August 6, 2006

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
245 PM MDT SUN AUG 6 2006

.SHORT TERM (TONIGHT THROUGH TUESDAY)...
CONVECTION QUICKER TO FIRE THIS MORNING OVER SOUTHWEST COLORADO...
CONCENTRATED ON A LINE FROM CORTEZ TO LONE CONE PEAK (WESTERN SAN
JUAN MOUNTAINS).  OUTFLOW BOUNDARY FROM NEW MEXICO MOVED INTO SW
COLORADO THIS MORNING AND PROBABLY BECAME STATIONARY IN THIS
VICINITY.  DEEP CONVECTION ALSO FIRED OVER THE ABAJO (BLUE)
MOUNTAINS IN SE UTAH.  STORMS HAVE BEEN SLOW MOVERS AND PRODUCING
HEAVY RAINFALL WITH SMALL MARBLE SIZED HAIL.  FARTHER NORTH...THE
AIR MASS IS A LITTLE DRIER WITH LESS NUMEROUS STORMS.

SUBTROPICAL MOISTURE PLUME OVER NEW MEXICO BEGINNING TO PUSH WEST...
WHICH HAS BEEN ADVERTISED BY THE MODELS FOR THE LAST COUPLE OF
DAYS.  FOR THE FAR SRN PORTION OF OUR FORECAST AREA...EXPECT THE
FLOW TO BECOME SOUTHEAST ON MONDAY AND ADVECTING DEEPER MOISTURE
WITH H7 MIXING RATIOS EXCEEDING 8 G/KG.  THEREFORE THE GENERAL TREND
WILL BE AN INCREASE OF AREAL THUNDERSTORM COVERAGE.  THE MOISTURE
DOES NOT REACH THE NRN ZONES AND STORMS OVER NWRN COLORADO WILL
BE ISOLATED.

PREFER THE GFS SOLUTION OVER THE WRF ON HOW THE CLOSED LOW EJECTS
NORTHEAST TOWARD THE NRN ROCKIES AND THE PLACEMENT OF THE HIGH
CENTER OVER THE SRN PLAINS.  THE EURO AND UKMET MODELS SHOW BETTER
AGREEMENT WITH THE GFS...WITH THE WRF THE ODD MAN OUT.  THEREFORE
THE GFS MOS POP GUIDANCE GENERALLY FOLLOWED WITH THE HIGHEST VALUES
FOR THE SAN JUAN MOUNTAINS.  THUNDERSTORM COVERAGE OVER THE NRN HALF
WILL INCREASE ON TUESDAY AND HAVE INDICATED THIS TREND IN THE POP
GRIDS.  TEMPERATURES WILL CONTINUE TO BE BELOW GUIDANCE DUE TO
AFTERNOON CLOUD COVER AND THE MOIST AIR MASS.

.LONG-TERM (TUESDAY NIGHT THROUGH SUNDAY)...
CLOSED LOW OFF CALIF OPENS AND LIFTS THROUGH OR/ID. THE SOUTH
CENTRAL US HIGH THEN SHIFTS BACK TO THE WEST. ENOUGH LOW LEVEL
MOISTURE TO KEEP DAILY ACTIVITY OVER THE HIGH COUNTRY WITH EMBEDDED
WAVES HELPING PUSH SOME OF THE CONVECTION INTO THE VALLEYS AT TIMES.
LOOKS EASIER TO IDENTIFY A SLIGHT DOWN TREND FOR THURSDAY NIGHT AND
FRIDAY THEN TO SEE A DEFINED INCREASE IN OUR WEATHER. OVERALL
FORECAST ON TRACK SO ONLY MINOR ADJUSTMENTS. DJC/21

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
.CO...NONE.
.UT...NONE.

&&

PF/DJC

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
433 AM MDT SUN AUG 6 2006

COZ001>014-017>023-UTZ022>025-027>029-071130-
ANIMAS RIVER BASIN-ARCHES/GRAND FLAT-CANYONLANDS/NATURAL BRIDGES-
CENTRAL COLORADO RIVER BASIN-
CENTRAL GUNNISON AND UNCOMPAHGRE RIVER BASIN-
CENTRAL YAMPA RIVER BASIN-DEBEQUE TO SILT CORRIDOR-
EASTERN UINTA BASIN-EASTERN UINTA MOUNTAINS-
ELKHEAD AND PARK MOUNTAINS-FLAT TOPS-
FOUR CORNERS/UPPER DOLORES RIVER-
GORE AND ELK MOUNTAINS/CENTRAL MOUNTAINS-GRAND AND BATTLEMENT MESAS-
GRAND VALLEY-LA SAL AND ABAJO MOUNTAINS-LOWER YAMPA RIVER BASIN-
NORTHWEST SAN JUAN MOUNTAINS-PARADOX VALLEY/LOWER DOLORES RIVER-
ROAN AND TAVAPUTS PLATEAUS-SAN JUAN RIVER BASIN-SOUTHEAST UTAH-
SOUTHWEST SAN JUAN MOUNTAINS-TAVAPUTS PLATEAU-
UNCOMPAHGRE PLATEAU AND DALLAS DIVIDE-UPPER GUNNISON RIVER VALLEY-
UPPER YAMPA RIVER BASIN-WEST ELK AND SAWATCH MOUNTAINS-
433 AM MDT SUN AUG 6 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN UTAH AND WESTERN
COLORADO.

.DAY ONE...TODAY AND TONIGHT

SHOWERS AND THUNDERSTORMS WILL DEVELOP THIS AFTERNOON AND EVENING...
BECOMING MOST NUMEROUS ACROSS SOUTHWEST COLORADO.

HEAVY RAIN...SMALL HAIL...GUSTY WINDS AND FREQUENT LIGHTNING WILL
ACCOMPANY SOME OF THE STORMS. EXCESSIVE RUNOFF AND THE THREAT OF
FLASH FLOODING AND MUD SLIDES WILL EXIST IN AREAS OF PERSISTENT HEAVY
RAIN.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

SCATTERED SHOWERS AND THUNDERSTORMS WILL OCCUR EACH DAY. THE THREAT
OF HEAVY RAIN...SMALL HAIL...GUSTY WINDS AND CLOUD TO GROUND
LIGHTNING WILL EXIST WITH THE THUNDERSTORMS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY OR TONIGHT...BUT SPOTTERS
ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER TO THE GRAND JUNCTION
NATIONAL WEATHER SERVICE OFFICE.

CUOCO