Damaging Wind in Colorado, July 5, 2001

WESTERN COLORADO & EASTERN UTAH AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
150 PM MDT THU JUL 5 2001

BLANKET OF HIGH CLOUDS OVER THE NORTHERN HALF OF THE FORECAST AREA
HELPING TO KEEP TEMPS FROM SOARING TOWARD RECORD HIGHS.  HOWEVER...
CLOUD COVER HAS BEEN SLOWLY THINNING FROM THE SOUTH...PER VISIBLE
SATELLITE...SO WE STILL HAVE A CHANCE AT MAKING A RUN TOWARD THE
TRIPLE DIGITS LATE THIS AFTERNOON.  CONVECTION OVER THE HIGHER
TERRAIN HAS BEEN SLOW TO FIRE...BUT RADAR IS STARTING TO SHOW SOME
RETURNS...ESPECIALLY OVER THE SAN JUANS AND THE MTNS OF NE UT.  THIS
TREND WILL CONTINUE THROUGH LATE THIS AFTERNOON WITH TSTM COVERAGE
INCREASING.

BIG QUESTION TONIGHT WILL BE WHETHER CONVECTION LINGERS AND RE-FIRES
LATE...OR IF WE WILL EXPERIENCE ANOTHER DIURNAL SHUTDOWN.  MODELS
REMAIN FAIRLY CONSISTENT WITH SHIFTING THE UPPER LEVEL HIGH
SLIGHTLY FURTHER EAST TONIGHT...ALLOWING BETTER SOUTHERLY FLOW TO
DEVELOP OVER THE REGION.  DEEPER MOISTURE PLUME OVER NEVADA
EXPECTED TO SHIFT EAST IN RESPONSE...REACHING EASTERN UT DURING THE
DAY FRIDAY.  AVN BLOWING UP A LITTLE SHORTWAVE OVER WESTERN CO
TONIGHT...WHICH LOOKS OVERDONE AND IS LIKELY THE REASON FOR THE
HIGH POPS ADVERTISED IN THE AVN MOS GUIDANCE.  LEANING TOWARD THE
MORE CONSERVATIVE AND LESS ACTIVE ETA/NGM/MESO-ETA RUNS...WHICH DO
SHOW A WEAK WAVE DEVELOPING TONIGHT...ALONG WITH A WEAK SPEED MAX
PUSHING INTO THE NRN PORTIONS OF THE FA.  WITH THIS IN MIND...WILL
REMOVE ANY MENTION OF EVENING SHOWERS/TSTMS...AND CARRY A THREAT OF
PRECIP THROUGHOUT THE NIGHT. HIGHEST POPS WILL AGAIN BE OVER THE
HIGHER TERRAIN...WITH THE LOWER VALLEYS LIKELY TO SEE MORE WIND THEN
RAIN.

SLIGHTLY BETTER POPS FOR EASTERN UTAH/EXTREME WESTERN COLORADO
FRIDAY/FRIDAY NIGHT...WITH ANOTHER REPEAT OF FRIDAY ON SATURDAY AS
UPPER HIGH MOVES LITTLE.  EXPECT TEMPS TO DROP BACK DOWN ANOTHER 2 OR
3 DEGREES THE NEXT TWO DAYS AS DEEPER MOISTURE MOVES IN AND H7 TEMPS
COOL SLIGHTLY.

EXTENDED (SUN-THU)...UPPER LVL HIGH DOMINATING WEATHER PATTERN WILL
GRADUALLY BEGIN TO SLIDE BACK WEST TOWARD THE FOUR CORNERS THROUGH
THIS PERIOD. MED RANGE MODELS INDICATE TEMPS CLOSER TO NORMAL FOR
EARLY JULY WITH H7 TEMPS 1-3C COOLER THAN OBSERVED THIS WEEK. MID LVL
MOISTURE WILL CONTINUE TO HANG AROUND...RE-CIRCULATING AROUND THE
UPR HIGH. DIURNAL CONVECTION LIKELY EACH DAY...ESPECIALLY OVER THE
MOUNTAINS. 7-500MB FLOW WEAKENS AS RIDGE AXIS APPROACHES...LEADING
TO VERY LITTLE PROPAGATION OF THUNDERSTORMS OFF THE HIGHER TERRAIN.
THUS...LOWER VALLEYS WILL STAY RAIN-FREE ONCE AGAIN (THE EXCEPTION
BEING THE HIGHER VALLEYS NEAR GUC/DRO).  DJN.83

.GJT...NONE.