Flash Flood Warning 6, NWS Grand Junction, CO

WESTERN COLORADO & EASTERN UTAH AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1248 PM MDT THU AUG 9 2001

...FLASH FLOOD WATCH FOR WESTERN COLORADO AND MOST OF EASTERN UTAH
THIS AFTERNOON AND EVENING...
PINPOINTING WHERE SLOW-MOVING THUNDERSTORMS WITH HEAVY RAIN WILL
DEVELOP IS THE MAIN FORECAST PROBLEM TODAY. MID-LEVEL SUBSIDENCE
FOLLOWING MESO-COMPLEX HELP CLEAR SKIES THIS MORNING...BUT PLENTY OF
MOISTURE REMAINS IN PLACE/ SFC DEWPTS NEAR 60F/ FOR THE SUN TO WORK
ON. BLV SOLAR INSULATION WILL BUILD ENERGY BENEATH WEAK MIDLVL CAP
WHICH SHOULD POP LATE THIS AFTERNOON ALLOWING FOR DEEP CONVECTION.
15Z GOES SOUNDING SHOWS SATURATED ATMOS ABOVE 700 MB WITH POTENTIAL
FOR PLENTY OF CAPE. AWIPS SOUNDING SHOWS 1500J OF ELEVATED CAPE ABOVE
LFC WITH FCST MAX TEMP OF ONLY 84. THETA-E RIDGE REMAINS OVER THE
AREA AS WELL.  WEAKER DYNAMIC TRIGGER THIS EVENING...AS SMALLISH VORT
MAX MOVING OVER THE AREA ABOUT 03Z IS THE ONLY FEATURE LESS
IMPRESSIVE THAN WEDNESDAY. ALL POINTS TO LATER START FOR CONVECTION
BUT MAY RESULT IN STRONGER CELLS. WILL HAVE MUCH HIGHER POPS FOR
FIRST PERIOD EVERYWHERE WITH HEAVY RAIN PSBL IN ALMOST EVERY ZONE.

GUIDANCE TEMPS FOR GJT SHOW BROAD VARIANCE BTWN MODELS...WITH MEX
DRASTICALLY COOL AND FWC NUMBER NEAR NORMAL FOR FRI. WILL GO JUST
BELOW WARMER GUIDANCE FOR FRI AS CLEARING/DRYING CONDITIONS SHOULD
PUSH IN WITH MORE NWLY FLOW FRIDAY AFTERNOON.  CUOCO

IN THE EXTENDED (SUN-THU)...MRF BACKED OFF DEVELOPING PAC NW TROUGH
EARLY NEXT WEEK...WITH ALL MODELS NOW SHOWING RIDGE OVER THE
SOUTHWEST THROUGH THE PERIOD. UPPER HIGH CENTER NEAR THE 4-CORNERS
EARLY NEXT WEEK...WITH SOME RETROGRESSION INDICATED WED AND THU.
MAY HAVE SOME SMALLER DISTURBANCES TOPPING RIDGE IN NW FLOW WED
AND THU BUT WILL ASSUME MAIN IMPACT WOULD BE EAST OF CWA AT THE
MOMENT. SOME MOISTURE LIKELY TO REMAIN UNDERNEATH RIDGE...BUT THIS
PATTERN SHOULD NOT REALLY FAVOR STRONG MONSOONAL MOISTURE INPUT. WILL
THUS INDICATE SOME DRYING ACROSS NE UT AND NW CO BY WED. OTHERWISE...
WILL NOT MAKE MUCH CHANGE TO CURRENT FORECAST OF WIDELY SCT/SCT
DIURNAL CONVECTION MAINLY OVER THE MOUNTAINS.  JAD

WESTERN COLORADO AND EASTERN UTAH EMERGENCY MANAGERS SHOULD MAINTAIN
A HIGH LEVEL OF WEATHER AWARENESS FOR THIS EVENING DUE TO THE
POTENTIAL FOR LOCAL HEAVY RAIN.

.GJT...FLASH FLOOD WATCH UNTIL MIDNIGHT FOR ALL OF WESTERN COLORADO
       AND MOST OF EASTERN UTAH...COZ01>23...UTZ22/25/27>29.