Flash Flood Warning 36, NWS Grand Junction, CO

944 
WGUS75 KGJT 170058
FFSGJT

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
658 PM MDT FRI SEP 16 2011

UTC019-037-170230-
/O.CON.KGJT.FF.W.0036.000000T0000Z-110917T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN JUAN UT-GRAND UT-
658 PM MDT FRI SEP 16 2011

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR SOUTHWESTERN GRAND AND
EXTREME NORTH CENTRAL SAN JUAN COUNTIES UNTIL 830 PM MDT...

AT 654 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THUNDERSTORMS WITH VERY HEAVY RAINFALL CONTINUING ACROSS THE WARNED 
AREA. SEVERAL SPOTTERS HAVE REPORTED VERY HEAVY RAIN WITH SOME 
FLOODING REPORTED IN MOAB BY THE GRAND COUNTY SHERIFF.

RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...CASTLE 
VALLEY...ARCHES NATIONAL PARK...DEAD HORSE POINT STATE PARK...THE 
FAR NORTHERN REACHES OF CANYONLANDS NATIONAL PARK...GREEN RIVER AND 
MOAB.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE FLOODING OF SMALL CREEKS
AND STREAMS...COUNTRY ROADS...NORMALLY DRY WASHES... AS WELL AS
FARMLAND ALONG THE BANKS OF CREEKS AND STREAMS.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY.

&&

LAT...LON 3893 11018 3893 11015 3899 11015 3900 10948
      3846 10933 3842 11002 3846 11004 3848 11001
      3852 11005 3853 11001 3855 11001 3858 11006
      3864 11006 3866 11010 3873 11012 3876 11010
      3891 11018

$$

NL

225 
WGUS75 KGJT 170231
FFSGJT

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
831 PM MDT FRI SEP 16 2011

UTC019-037-170242-
/O.EXP.KGJT.FF.W.0036.000000T0000Z-110917T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN JUAN UT-GRAND UT-
831 PM MDT FRI SEP 16 2011

...THE FLASH FLOOD WARNING THAT WAS IN EFFECT FOR SOUTHWESTERN GRAND
AND EXTREME NORTH CENTRAL SAN JUAN COUNTIES WILL BE ALLOWED TO EXPIRE
AT 830 PM MDT...

THE THUNDERSTORMS WITH HEAVY RAINFALL HAVE EXITED THE WARNED AREA 
BUT LIGHT RUNOFF FROM THESE STORMS MAY CONTINUE OVER THE NEXT FEW 
HOURS. STREAMS AND CREEKS IN THE WARNED AREA WERE BEGINNING TO 
RECEDE...ENDING THE FLOOD THREAT. IF FLOODING HAS BEEN 
OBSERVED...PLEASE REPORT IT TO YOUR LOCAL LAW ENFORCEMENT AGENCY.

LAT...LON 3893 11018 3893 11015 3899 11015 3900 10948
      3846 10933 3842 11002 3846 11004 3848 11001
      3852 11005 3853 11001 3855 11001 3858 11006
      3864 11006 3866 11010 3873 11012 3876 11010
      3891 11018

$$

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
315 PM MDT FRI SEP 16 2011

.SHORT TERM /TONIGHT THROUGH MONDAY/...

THE PESKY AREA OF LOW PRESSURE HAS BEEN ABSORBED IN THE NEARLY ZONAL
FLOW TODAY...BUT SOME ROTATION IS STILL EVIDENT ON WATER VAPOR
IMAGERY.  THE CENTER OF THIS ROTATION HAS JUST ABOUT EXITED OUR CWA
AND WILL DO SO IN THE NEXT FEW HOURS.  THIS WAS THE CAUSE OF THE
EARLIER RAINSHOWERS...STORMS...AND LOW CLOUDS.  WITH THE LOW MOVING
OFF AND CLOUDS BURNING OFF...AMPLE MOISTURE REMAINS FOR ANOTHER ROUND
OF CONVECTION AND STORMS THIS AFTN.  ANTICIPATE PULSE-TYPE STORMS TO
CONTINUE FORMING WITH SOME BRIEF GUSTY WINDS AND HEAVY RAIN THROUGH
THIS EVENING.  THOSE AREAS NOT SEEING SHOWERS OR STORMS WILL SEE
PLENTY OF CLOUDS AND SOMEWHAT COOL TEMPERATURES.

FURTHER TO THE WEST OVER CENTRAL UT...STRONG CONVECTION HAS FIRED IN
RESPONSE TO APPROACHING TROF THAT IS BEING SUPPORTED BY A 100+ KT
JET.  GUIDANCE SUGGESTS THAT THIS LINE WILL ENTER CWA IN THE NEXT 6
TO 8 HRS SO STORMS AND SHOWERS CAN BE EXPECTED TO CONTINUE THROUGH
THIS EVENING AT LEAST.  FORECAST REFLECTS THIS THINKING WITH
LOWERED POPS AFTER MIDNIGHT.  AS UPPER LEVEL SUPPORT MOVES OVER
AREA TOMORROW...ANOTHER ROUND OF SHOWERS AND STORMS POSSIBLE WITH
NORTHERN AREAS BEING FAVORED.  HOWEVER...WIDESPREAD INSTABILITY AND
CONTINUED MOISTURE IN ATMOSPHERE WILL ALLOW CONVECTION ACROSS ENTIRE
CWA DYING DOWN AFTER SUNSET.

BY SUNDAY...FINALLY...AN AREA OF HIGH PRESSURE BUILDS IN SHUTTING
OFF MOISTURE PLUME FROM THE SOUTH AS W TO NW FLOW SETS UP.  THE CWA
SHOULD DRY OUT ALLOWING FOR A WARM...SUNNY DAY WITH MINIMAL CHANCE
FOR PRECIP.  GFS PAINTS A DIFFERENT PICTURE BUT THE ODD MAN OUT AS
EUROPEAN AGREES QUITE WELL WITH NAM12.

.LONG TERM /MONDAY THROUGH FRIDAY/...

GFS AND EC MODELS A BIT AT ODDS THIS MORNING AS GFS DEPICTS A
WESTERLY FLOW MONDAY WITH A SHRT WV MOVING INTO THE GRT BASIN.
MEANWHILE THE EC SHOWS A RIDGE OF HIGH PRESSURE. SENSIBLE WEATHER
HOWEVER NOT ALL THAT MUCH DIFFERENT WITH ONLY VERY LOW POPS CWA
WIDE FOR MONDAY AFTERNOON. CURRENT HPC GUIDANCE SIDES WITH THE EC SO
WILL BIAS THIS ENTIRE LONG TERM FORECAST ACCORDINGLY. ON TUESDAY
THERE WILL BE A SLIGHTLY BETTER CHANCE OF CONVECTION AS INSTABILITY
EXISTS IN A WEST-NORTHWEST FLOW. LITTLE MOISTURE OR FORCING SEEN SO
POPS WILL REMAIN LOW AND NOT ENOUGH TO JUSTIFY MORE THAN ISOLATED
TSTMS OVER MTN LOCATIONS. HIGH PRESSURE AMPLIFIES OVER THE REGION
WEDNESDAY THROUGH FRIDAY BRINGING DRY MILD CONDITIONS REGION.

TEMPERATURES DURING THIS LONG TERM PERIOD WILL GENERALLY BE NEAR TO
A LITTLE ABOVE SEASONAL NORMALS.

&&

.AVIATION...VISIBLE IMAGERY CONTINUES TO SHOW RESIDUAL MOISTURE
OVER MAINLY CO THIS AFTN WITH SOME LOWER CIGS...SHOWERS...AND
VICINITY STORMS BEING REPORTED AT TAF SITES THOUGH WELL INTO VFR
CATEGORIES. THIS WILL CONTINUE THROUGH THE AFTERNOON WITH ISOLATED
SHOWERS AND STORMS CONTINUING FOR ALL SITES...WITH LESSER CHANCES AT
KVEL. HEAVIER SHOWERS MAY CAUSE BRIEF MVFR WITH QUICK DROPS IN
VISIBILITIES BUT BY IN LARGE...VFR IS EXPECTED TO REMAIN THE DOMINANT
FLIGHT CATEGORY. SOME MOUNTAINTOP OBSCURATION IS ALSO EXPECTED.
THE NEXT DISTURBANCE WILL ALLOW UNSETTLED WX TO CONTINUE INTO THIS
EVENING WITH ACTIVITY ENDING AFTER MIDNIGHT.  EXPECT SIMILAR
CONDITIONS TOMORROW.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...NONE.
UT...NONE.

&&

SHORT TERM...TGR
LONG TERM....MC
AVIATION.....TGR

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
600 AM MDT FRI SEP 16 2011

COZ001>014-017>023-UTZ022>025-027>029-171200-
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-
600 AM MDT FRI SEP 16 2011

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

.DAY ONE...TODAY AND TONIGHT

NUMEROUS SHOWERS WITH A FEW THUNDERSTORMS CAN BE EXPECTED IN THE
HIGH COUNTRY.  SHOWERS AND STORMS WILL BE LESS NUMEROUS IN THE
VALLEYS.  THE STRONGEST STORMS WILL PRODUCE BRIEF MODERATE TO HEAVY
RAIN SHOWERS ACROSS SOUTHEAST UTAH AND SOUTHWEST COLORADO.
SCATTERED SHOWERS AND ISOLATED STORMS WILL CONTINUE TONIGHT.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

SATURDAY...EXPECT SCATTERED AFTERNOON AND EVENING THUNDERSTORMS WITH
MOST STORMS OCCURRING IN THE MOUNTAINS...BUT SOME STORMS WILL DRIFT
OVER THE VALLEYS.

SUNDAY THROUGH TUESDAY...MUCH DRIER BUT ISOLATED AFTERNOON
THUNDERSTORMS CAN BE EXPECTED OVER THE COLORADO MOUNTAINS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED TODAY OR TONIGHT.