Flash Flood Warning 10, NWS Grand Junction, CO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
305 PM MDT FRI AUG 8 2008

.SHORT TERM...TODAY THROUGH SUNDAY...
STEERING WINDS A LITTLE HIGHER TODAY THAN THURSDAY AND THIS HAS
PREVENTED HEAVY RAIN FROM FORMING OVER A SINGLE LOCATION.  SPEED AND
DIRECTIONAL SHEAR IS STILL LIGHT...BUT THERE MAY BE ENOUGH MID
LEVEL FLOW (ABOUT 15 KNOTS) FOR ISOLATED SEVERE HAIL.  BUT FLASH
FLOODING WILL REMAIN THE MAIN WEATHER THREAT THROUGH THE EVENING.
THE STRONG CELLS ARE STILL PRODUCING HEAVY SHOWERS WITH SIGNIFICANT
RAINS IN A SHORT PERIOD OF TIME.  TRAINING CELLS MAY OCCUR WITH THE
FAVORED AREA ACROSS THE NORTH...WHERE SHORT WAVE WILL DEPART THE
FORECAST AREA AND MOVE EAST OF THE DIVIDE THIS EVENING.

BEHIND DEPARTING SHORT WAVE...THE FLOW BECOMES NORTHWEST AND THIS
BRINGS INTO SOME DRIER AIR.  DRY AIR ADVECTION IS WEAK AND MOISTURE
WILL REMAIN TRAPPED BENEATH THE RIDGE AXIS.  WITHOUT AN UPPER
LEVEL DISTURBANCE...MOST OF THE STORMS ON SATURDAY WILL BE CONFINED
OVER THE MOUNTAINS BUT A FEW OF THESE STORMS WILL MOVE OFF THE HIGH
TERRAIN AND IMPACT VALLEY LOCATIONS.

SHOULD SEE A LITTLE LESS CONVECTIVE ACTIVITY ON SUNDAY.  HOWEVER...
H7 SPECIFIC HUMIDITY WILL STILL EXCEED 6 G/KG AND THIS IS STILL
MOIST (JUST NOT AS MOIST COMPARED TO THE LAST 2 DAYS).  LIKE
SATURDAY...MANY OF THE STORMS WILL HUG THE HIGH TERRAIN UNTIL LATE
AFTERNOON.

.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
PATTERN SHIFT STARTS SUNDAY NIGHT WITH RIDGE SUPPRESSING SLIGHTLY
WITH PASSING WAVE ACROSS SOUTHERN CANADA. THIS WILL SHIFT THE DEEP
MONSOONAL PLUME SOUTH AND EAST OF THE FORECAST AREA...WITH
CONVECTIVE ACTIVITY BECOMING MORE ISOLATED IN NATURE EACH AFTERNOON
AND EVENING. RIDGE REBOUNDS BY LATE IN THE WEEK WITH ANOTHER SURGE
OF MOISTURE EXPECTED. CURRENT IDEA OF INCREASING POPS BY THE END OF
THE WEEK REMAINS REASONABLE.  TEMPS VARY LITTLE THROUGH THE PERIOD
WITH MOST OF THE FORECAST AREA REMAINING NEAR SEASONAL NORMALS.

&&

.AVIATION...
EXPECT SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS THE
REGION THROUGH LATE THIS EVENING. STORMS WILL LIKELY BRING
MVFR CIGS AND VSBY WITH AN ISOLATED FEW RESULTING IN BRIEF IFR
CONDITIONS.

&&

.HYDROLOGY...
AN EXCEEDINGLY MOIST ATMOSPHERE REMAINS IN PLACE OVER EASTERN
UTAH AND WESTERN COLORADO THIS EVENING. SOME OF THE STORMS WILL
PRODUCE HEAVY SHOWERS.  WITH SATURATED SOILS...RUNOFF FROM THESE
HEAVY SHOWERS COULD BE FAST AND PRODUCE FLASH FLOODING. A FLASH FLOOD
WATCH HAS BEEN ISSUED FOR ALL OF EASTERN UTAH AND WESTERN COLORADO
EFFECTIVE FROM NOON TO 10 PM THIS EVENING.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
.CO...FLASH FLOOD WATCH IN EFFECT UNTIL 10 PM MDT FOR ALL
       WESTERN COLORADO ZONES.
.UT...FLASH FLOOD WATCH IN EFFECT UNTIL 10 PM MDT FOR ALL
       EASTERN UTAH ZONES.

SHORT TERM.....PF
LONG TERM......JDC
AVIATION.......TGJT
HYDROLOGY......TGJT

HAZARDOUS WEATHER OUTLOOK UPDATE
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
545 AM MDT FRI AUG 8 2008

COZ001>014-017>023-UTZ022>025-027>029-091200-
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-
545 AM MDT FRI AUG 8 2008

...FLASH FLOOD WATCH IN EFFECT FOR ALL OF EASTERN UTAH AND
WESTERN COLORADO FROM NOON UNTIL 10 PM MDT...

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

.DAY ONE...TODAY AND TONIGHT

SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
DEVELOP ACROSS EASTERN UTAH AND WESTERN COLORADO TODAY...LINGERING
THROUGH TONIGHT. HEAVY RAIN IS EXPECTED WITH THE STRONGER STORMS
RESULTING IN AN INCREASED POTENTIAL FOR FLOODING. AS A RESULT...A
FLASH FLOOD WATCH IS IN EFFECT FOR ALL OF WESTERN COLORADO AND
EASTERN UTAH THROUGH EVENING. IN ADDITION TO HEAVY RAIN...TODAYS
THUNDERSTORMS WILL BE CAPABLE OF PRODUCING GUSTY WINDS TO AROUND 35
MPH...SMALL HAIL...AND FREQUENT DANGEROUS LIGHTNING.

PLEASE SEE THE GRAND JUNCTION NATIONAL WEATHER SERVICE WEB SITE AT
WEATHER.GOV/GJT FOR THE LATEST INFORMATION.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THERE IS A CHANCE FOR SHOWERS AND THUNDERSTORMS EACH AFTERNOON AND
EVENING THROUGH THE MIDDLE OF NEXT WEEK.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED LATER THIS AFTERNOON AND INTO THE
EVENING HOURS. SPOTTERS WOULD BE EXPECTED TO REPORT HEAVY RAIN AND
ANY KNOWN FLOODING AS SOON AS SAFELY POSSIBLE.

MC/NL