Flash Flood Warning 6, NWS Grand Junction, CO

000 
RWUS32 KGJT 302324
FFSGJT

COC091-310115-

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
525 PM MDT WED AUG 30 2000

...A FLASH FLOOD WARNING CONTINUES UNTIL 730 PM MDT FOR EAST CENTRAL 
OURAY COUNTY...

AT 520B PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THUNDERSTORMS WITH VERY HEAVY RAINFALL 8 MILES NORTHEAST OF 
RIDGWAY...DRIFTING SLOWLY TO THE NORTHEAST

SLOW MOVING THUNDERSTORMS ARE PRODUCING TORRENTIAL RAINFALL IN THE 
WARNED AREA. THE DOPPLER RADAR NEAR GRAND JUNCTION HAS ESTIMATED 
THAT OVER 3.0 INCHES OF RAIN HAS FALLEN SINCE 400 PM MDT. RUNOFF 
FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO OCCUR. 
SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE....COW CREEK 
AND ITS TRIBUTARIES.

THOSE TRAVELLING ALONG 8 ROAD IN EASTERN OURAY COUNTY COULD 
EXPERIENCE FLOODWATERS ON THE ROAD...ESPECIALLY ALONG BRIDGES AND 
CULVERTS. HIGHER WATERS ON COW CREEK CAN ALSO BE EXPECTED BY EVENING 
NEAR ROUTE 550 WHERE THE CREEK ENTERS THE UNCOMPAHGRE RIVER.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT. IT IS 
IMPORTANT TO KNOW WHERE YOU ARE RELATIVE TO STREAMS...RIVERS...OR 
CREEKS WHICH CAN BECOME KILLERS IN HEAVY RAINS. CAMPZERS SHOULD AVOID 
CAMPING ALONG STREAMS OR CREEKS DURING THREATENING RAINS.

LAT...LON 3818 10778 3806 10762 3819 10759 3833 10767

BA

000 
RWUS32 KGJT 310115
FFSGJT

COC091-310215-

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
715 PM MDT WED AUG 30 2000

...THE FLASH FLOOD WARNING FOR EAST CENTRAL OURAY COUNTY HAS BEEN CANCELLED...

AT 715 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THAT THE THUNDERSTORMS THAT PRODUCED HEAVY RAIN OVER EAST CENTRAL 
OURAY COUNTY HAD MOVED NORTHEAST AND DISSIPATED.

THE DOPPLER RADAR NEAR GRAND JUNCTION ESTIMATED THAT BETWEEN 3.0 AND 
4.0 INCHES OF RAIN FELL EAST/NORTHEAST OF RIDGWAY LATE THIS 
AFTERNOON. THE HEAVIEST RAIN FELL OVER THE UPPER PORTIONS OF COW 
CREEK AND ITS TRIBUTARIES THAT FLOW IN FROM THE NORTH AND EAST. HIGH 
WATER IS LIKELY ON THESE STREAMS THIS EVENING...BUT SHOULD RECEDE 
LATER TONIGHT. THOSE TRAVELING ALONG 8 ROAD IN EASTERN OURAY COUNTY 
COULD EXPERIENCE WATER ON THE ROAD...ESPECIALLY ALONG BRIDGES AND 
CULVERTS. 

HOWEVER...NO ADDITIONAL HEAVY RAINS ARE EXPECTED IN THAT AREA 
TONIGMHT.

BA

WESTERN COLORADO & EASTERN UTAH AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
230 PM MDT WED AUG 30 2000

EXTENSIVE CLOUD COVER ACROSS THE NORTHERN CWA HAS INHIBITED SHOWER
ACTIVITY.. BUT SOME ISOLATED CELLS HAVE FIRE UP AS CLOUD MASS HAS
BECOME BROKEN.  DRIER AIR WITH SUBSIDENCE HAS ADVECTED INTO THE
SOUTHERN ZONES.. PRECIPITABLE WATER PER GOES SOUNDER HAS DROPPED TO
AROUND THREE QUARTERS OF AN INCH.  DRIER AIR WILL ADVECT TO THE
NORTHERN ZONES THIS EVENING AND SCATTERED SHOWERS AND THUNDER SHOULD
TAPER OFF AFTER SUNSET.  BUT CONVECTIVE ACTIVITY WILL INCREASE IN THE
FOUR CORNERS AREA AS AN UPPER AIR DISTURBANCE OVER NORTHERN
MEXICO/SOUTHEAST ARIZONA TRACKS NORTHWARD.  AVN MODEL INITIALIZED
THIS SYSTEM BETTER AND PROGS IT TO REACH THE MOAB VICINITY BY
MORNING.  SHOWERS AND THUNDERSTORMS WILL FOLLOW THE UPPER LEVEL
DISTURBANCE AS IT MOVES NORTHWARD OVERNIGHT.

FARTHER WEST ON THE LARGER SYNOPTIC SCALE.. CLOSED LOW OFF THE
CALIFORNIA COAST GETS PICKED UP BY VORTICITY LOBE ROTATING AROUND
THE POLAR VORTEX.  CLOSED LOW BECOMES AN OPEN WAVE BY THURSDAY
AFTERNOON AND BEGINS TO SHIFT EASTWARD.  FOR THE FORECAST AREA..
SPEED SHEAR BEGINS TO INCREASE THAT MAY GENERATE ISOLATED STRONG
CELLS ACROSS CWA THURSDAY AFTERNOON AND EVENING.  MORE STRONG
CONVECTIVE ACTIVITY EXPECTED FRIDAY WITH AN INCREASE OF MOISTURE
AND WIND ALOFT.  ETA/AVN MODEL DATA INDICATE 850-400MB SPEED SHEAR
IN THE 40 TO 50 KNOT RANGE WITH SOME DIRECTIONAL SHEAR.  UPPER LEVEL
DIVERGENCE INCREASES AS WESTERN COLORADO WILL BE IN THE EXIT REGION
OF 90 KNOT 250 MB JET.  THIS SITUATION WILL NEED TO BE MONITORED
FOR THE POTENTIAL OF STRONG AND LOCALIZED SEVERE STORMS.

SATURDAY BECOMES A TRANSITION DAY AND THE BEGINNING OF THE END OF
THE MONSOON SEASON.  SURFACE PROGS INDICATE WEAK COLD FRONTAL PASSAGE
BY SATURDAY MORNING.  BUT WITH WIND ALOFT FROM THE SOUTHWEST.. COLD
FRONT WILL BE SHALLOW AND WILL BE SLOW TO SPREAD OVER FORECAST AREA.
PROXIMITY OF JET ALOFT WILL HELP GENERATE MORE CONVECTIVE ACTIVITY..
BUT MOISTURE CONTENT WILL BE LESS AS DRIER AIR SPREADS FROM THE WEST.
BY SUNDAY AND MONDAY.. THE AIR MASS WILL BE CONSIDERABLY DRIER WITH
OVERHEAD JET AXIS ORIENTED WEST TO EAST NEAR THE COLORADO AND NEW
MEXICO BORDER.  BUT MINOR IMPULSES EMBEDDED WITHIN CYCLONIC FLOW MAY
INDUCE OROGRAPHIC SHOWERS AND THUNDER.. BUT THE MAIN MESSAGE WILL BE
FOR MUCH DRIER CONDITIONS.

FRISBIE

.GJT...NONE.