Heavy Rain in Colorado, September 8, 2005

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
230 PM MDT WED SEP 7 2005

.SHORT TERM (TONIGHT THROUGH FRIDAY)...
A SUBTROPICAL RIDGE REMAINS POSITIONED FROM NORTHERN MEXICO ACROSS
NORTH TEXAS AND OKLAHOMA WHILE AN UPPER LOW IS POSITIONED OFF THE
NORTHERN CALIFORNIA COAST. SOUTHWEST FLOW IS IN PLACE OVER THE
FORECAST AREA BETWEEN THESE FEATURES. PRECIPITABLE WATER SPANS FROM
ABOUT 1 INCH OVER OVER FAR SOUTH TO ABOUT 1/2 INCH ACROSS THE FAR
NORTH PER GOES SOUNDER DATA. THUNDERSTORMS WILL CONTINUE TO BE
CONCENTRATED OVER THE HIGH TERRAIN THIS AFTERNOON AND EVENING WITH
LITTLE DYNAMIC SUPPORT. MAIN STORM THREAT WILL BE LOCALLY HEAVY RAIN,
ESPECIALLY SOUTH WHERE MOISTURE IS MORE ABUNDANT. SUBTLE WAVES
UNACCOUNTED FOR BY THE MODELS MAY GENERATE A FEW NOCURTNAL SHOWERS OR
THUNDERSTORMS OVERNIGHT.

THE UPPER LOW OFF THE CALIFORNIA COAST WILL MOVE SLOWLY INLAND
THURSDAY. LITTLE CHANGE OVER EASTERN UTAH AND WESTERN COLORADO THOUGH
WITH ANOTHER ROUND OF DIURNALLY DRIVEN CONVECTION. HIGHEST POPS ONCE
AGAIN OVER THE MOUNTAINS AND IN THE FOUR CORNERS VICINITY.
TEMPERATURES EXPECTED TO BE NEAR PERSISTENCE.

MODELS DIVERGE ON HANDLING OF THE CALIFORNIA CLOSED LOW THURSDAY
NIGHT INTO FRIDAY. FAVORED THE FASTER SOLUTION OF THE NAM AS HPC
SUGGESTS. IT LOOKS LIKE THE BEST DYNAMIC FORCING WILL OCCUR FRIDAY
AFTERNOON AND EVENING AS THE UPPER LOW SHEARS ACROSS UTAH AS AN OPEN
WAVE AND A SURFACE BOUNDARY MOVES INTO THE AREA. THE TAIL END OF AN
UPPER JET IS PROGGED OVERHEAD AS WELL WITH WIND SHEAR INCREASING
CONSIDERABLY. INSTABILITY MAY BE LIMITED FROM WIDESPREAD CLOUD COVER
BUT THE SYSTEM WILL MOVE THROUGH DURING MAX HEATING AND DYNAMICS AND
MOISTURE LOOK SUFFICIENT ENOUGH FOR STRONG STORMS TO DEVELOP FRIDAY
AFTERNOON. TRENDED MAX TEMPERATURES DOWN SEVERAL DEGREES FRIDAY WITH
FALLING HEIGHTS AND INCREASED CLOUD COVER. TIGHTENING GRADIENT AHEAD
OF THIS SYSTEM WILL KICK THE WINDS UP FRIDAY, ESPECIALLY ACROSS THE
NORTH WHERE SURFACE BOUNDARY WILL BE MORE ROBUST. LINDQUIST

.LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)...GFS IS SHOWING
REASONABLE RUN-TO-RUN CONTINUITY WITH THE WEST COAST TROF COMING
ONSHORE EARLY FRIDAY. AFTER THAT...A REPEATING SERIES OF ONSHORE
TROFS THAT QUICKLY EJECT TO OUR NORTH WILL BE THE WEATHER PATTERN
OF NEXT WEEK.

(FRIDAY AND SATURDAY)...A CLOSED LOW OVER CALIFORNIA WILL WEAKEN AND
MOVE INTO THE GREAT BASIN. DESPITE THE WEAKENING...AMPLE MOISTURE
LOOKS TO BE PRESENT AND IS FORECAST TO BE ITS DEEPEST DURING THE
OVERNIGHT HOURS. THE MAIN CENTER OF THE SHORTWAVE WILL PASS OVER NE
UTAH AND NW COLORADO LATE FRIDAY/EARLY SATURDAY. SOME JET SUPPORT
WILL ALSO BE AVAILABLE...WITH THE RIGHT REAR QUAD OF AN 80 KNOT JET
OVER THE NORTHERN PORTION OF THE CWA DURING THE TIME.

(SUNDAY THROUGH WEDNESDAY)...DRYING WILL BE THE WORD AS THE UPPER
LOW EJECTS QUICKLY TO THE NORTHEAST. ANOTHER TROF IS FORECAST TO DROP
DOWN THE WEST COAST ON SUNDAY...FOLLOWED BY ITS NORTHEAST EJECTION ON
MONDAY/TUESDAY. MOISTURE WILL BE LIMITED ACROSS OUR AREA...BUT SOME
ENERGY IN THE BASE OF THE TROF WILL SCRATCH THE NORTHERN PORTION OF
THE CWA. ISOLATED AFTERNOON MOUNTAIN CONVECTION WILL BE POSSIBLE...
MAINLY NORTH. PARTLY CLOUDY ELSEWHERE.

TEMPERATURES WILL BE NEAR NORMAL THROUGHOUT THE PERIOD WITH
LITTLE IN THE WAY OF DAY TO DAY VARIATION.

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

&&

TAL/BA

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
750 AM MDT WED SEP 7 2005

CORRECTED DUPLICATE WORDING

COZ001>014-017>023-UTZ022>025-027>029-081200-
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-
750 AM MDT WED SEP 7 2005

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

.DAY ONE...TODAY AND TONIGHT...

SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP THIS AFTERNOON AND
WILL LAST THROUGH MID EVENING BEFORE DECREASING.  THE BEST THREAT OF
THUNDERSTORMS WILL BE OVER THE WEST CENTRAL AND SOUTHWESTERN
MOUNTAINS OF COLORADO.  THESE STORMS WILL BE CAPABLE OF GENERATING
HEAVY RAIN...SMALL HAIL...GUSTY WINDS...AND CLOUD TO GROUND
LIGHTNING.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY...

THURSDAY AND FRIDAY...THERE WILL BE A CHANCE OF SHOWERS AND
THUNDERSTORMS...ESPECIALLY OVER THE MOUNTAINS OF SOUTHWESTERN
COLORADO.

SATURDAY AND SUNDAY...THERE WILL BE A SLIGHT CHANCE OF AFTERNOON
MOUNTAIN THUNDERSTORMS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY OR TONIGHT.