000
FXUS65 KBOU 201715
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
1115 AM MDT WED JUL 20 2011
.UPDATE...
LOOKING AT WATER VAPOR IMAGERY THE MONSOONAL MOISTURE FETCH IS
STRETCHED OVER SOUTHEASTERN COLORADO WITH DRYING MOVING IN FROM
THE NORTHWEST. THEREFORE SHOULD SEE STORMS TODAY WITH LESS HEAVY
RAIN POTENTIAL AND MORE GUSTY WINDS AND SMALL HAIL POTENTIAL. WITH
THE MOISTURE FETCH OVER THE SOUTHEASTERN PART OF THE STATE...WILL
MOST LIKELY SEE THE BULK OF THE ACTIVITY ALONG AND SOUTH OF
INTERSTATE 76 OVER THE PLAINS AND ALONG AND SOUTH OF THE
INTERSTATE 70 CORRIDOR OVER THE MOUNTAINS. HAVE INCREASED
POPS...QPF AND SKY COVER MAINLY OVER PARK COUNTY...PALMER DIVIDE AND EAST
TO LINCOLN COUNTY IN ANTICIPATION OF MORE ACTIVITY HERE.
&&
.PREV DISCUSSION... /ISSUED 351 AM MDT WED JUL 20 2011/
SHORT TERM...UPPER LEVEL HIGH WILL CONTINUE TO DRIFT EASTWARD TODAY
AS AN UPPER LEVEL TROUGH MOVES ACROSS THE NORTHERN STATES. FLOW
ALOFT WILL SHIFT MORE WESTERLY TODAY. THIS WILL CUT OFF SOME OF THE
MONSOONAL MOISTURE...ESPECIALLY OVER NORTH CENTRAL COLORADO.
PRECIPITABLE WATER VALUES FALL TO 0.4-0.8 INCHES OVER THE HIGH
COUNTRY. PLAINS ARE ABLE TO HOLD ON TO SOME LOW LEVEL MOISTURE SO
PRECIPITABLE WATER VALUES ONLY DROP TO 0.8-1.2 INCHES. CAPES WILL BE
PRIMARILY 500-1000 J/KG THIS AFTERNOON. SHOULD BE ENOUGH MOISTURE AND
INSTABILITY TO TRIGGER ISOLATED TO SCATTERED THUNDERSTORMS THIS
AFTERNOON AND EVENING. CHANCES FOR STORMS WILL BE BETTER SOUTH WHERE
GREATER MOISTURE WILL BE. BECAUSE OF THE DECREASE IN MOISTURE AND A
EAST TO NORTHEAST STORM MOVEMENT AROUND 20 KNOTS...FLASHING FLOODING
THREAT WILL BE VERY LOW. AIRMASS TODAY ONLY COOLS A FEW DEGREES SO
HIGHS SHOULD CLIMB INTO THE 90S AGAIN THIS AFTERNOON.
LONG TERM...BROAD ANTICYCLONIC CIRCULATION AROUND A STRONG
SUBTROPICAL HIGH POSITIONED OVER ERN TEXAS AND THE BERMUDA HIGH OFF
THE SOUTHEAST U.S. COAST WILL CONTINUE TO TRANSPORT A DEEP FETCH OF
SUBTROPICAL/TROPICAL MOISTURE NORTHWARD OUT OF MEXICO AND UP THE
WESTERN SIDE OF THE ROCKIES EARLY IN THE PERIOD. OUTFLOW FROM
HURRICANE DORA MOVING UP THE SWRN COAST OF MEXICO WILL FURTHER
ENHANCE THIS MOISTURE STREAM...ALTHOUGH MODELS SHOW MOST OF THE
MOISTURE FROM THIS SOURCE HEADING FOR THE DESERT SOUTHWEST AND NOT
SO MUCH FOR NEW MEXICO AND COLORADO. AT ANY RATE...THERE SHOULD
STILL BE ADEQUATE MOISTURE AROUND TO FUEL SCATTERED AFTERNOON/
EVENING T-STORMS IN THE MTNS/FOOTHILLS AND ISOLATED T-STORMS IN
THE VALLEYS AND ON THE PLAINS OF NORTH CNTRL AND NERN COLORADO
WITH STRONG DAYTIME HEATING ON THURSDAY. AND WITH INTEGRATED
PRECIPITABLE WATER /IPW/ VALUES HOOVERING AROUND AN INCH...CAN/T
RULE OUT A FEW LATE DAY GULLY WASHERS. SINCE THIS CONVECTION WILL
BE MAINLY HEAT DRIVEN...SHOULD SEE THE BULK OF THIS ACTIVITY
ENDING NOT LONG AFTER SUNSET.
ON FRIDAY...MODELS SHOW THE SRN GREAT PLAINS HIGH AND BERMUDA HIGH
SHIFTING WESTWARD WHICH CAUSES THE MONSOON MOISTURE PLUME TO
DEFLECT TOWARDS THE SWRN U.S. AND AWAY FROM COLORADO. SHOULD ALSO
SEE SOUTHWESTERLY FLOW ALOFT STRENGTHENING ON FRIDAY AS AN UPPER
TROUGH DROPS IN FROM THE PACIFIC NORTHWEST. ALL THIS MEANS WE SHOULD
SEE A DROP OFF IN THUNDERSTORM COVERAGE TOGETHER WITH WARMER
TEMPERATURES ON FRIDAY.
OVER THE WEEKEND...MODELS CONTINUE TO SHOW A STRONG BERMUDA HIGH
MIGRATING WESTWARD...SKIPPING OVER THE FLORIDA PENINSULA ON SUNDAY
AND MOVING OVER NERN GULF OF MEXICO BY MONDAY. THIS WESTWARD
PROGRESSION WILL DEFLECT THE MAIN AXIS OF THE MONSOON MOISTURE PLUME
FARTHER WEST OVER SRN CALIFORNIA AND ARIZONA...AND AWAY FROM
COLORADO. HOWEVER...EARLIER MODEL RUNS SHOWED THE HOT UPPER RIDGE
OVER THE SRN GREAT PLAINS ACTUALLY MOVING OVER CNTRL AND SRN ROCKY
MTN REGION...AND TRAPPED BENEATH IT A FAIR AMOUNT OF SUBTROPICAL
MOISTURE. FOR NOW WILL HANG ONTO THE IDEA THAT THERE SHOULD BE
ENOUGH ATMOSPHERIC MOISTURE AND HEATING TO WARRANT MENTION OF AT
LEAST A SLIGHT CHANCE OF LATE DAY STORMS SATURDAY THROUGH TUESDAY.
COULD ACTUALLY SEE THE CHANCE FOR STORMS COMING UP ON TUESDAY WITH
THE UPPER TROUGH PASSING TO OUR NORTH. TEMPERATURES DURING THE
PERIOD THURSDAY-TUESDAY SHOULD REMAIN ABOVE AVERAGE WITH THE WARMEST
READINGS EXPECTED ON FRIDAY.
&&
.AVIATION...SCATTERED THUNDERSTORMS WILL FORM THIS AFTERNOON AND
EVENING. APPEARS THERE IS A GOOD CHANCE FOR STORMS TO AFFECT THE
AIRPORTS...INCLUDING KDEN. MAV GUIDANCE SHOWING A 85-90 PERCENT
CHANCE OF A THUNDERSTORMS BETWEEN 18-06Z TODAY AT KDEN...KAPA AND
KBJC. BEST CHANCE FOR STORMS LOOKS TO BE 22-02Z. STORMS WILL FIRE
OVER THE HIGHER TERRAIN AND THEN MOVE EASTWARD. BRIEF HEAVY RAIN AND
OUTFLOW WIND GUSTS TO 40 KNOTS WILL BE THE MAIN THREAT TODAY.
.HYDROLOGY...THE THREAT FOR FLASH FLOODING TODAY IS LOW DUE TO A
DRIER AIRMASS AND FASTER MOVING STORMS.
MONSOON MOISTURE IS EXPECTED TO REMAIN OVER COLORADO FOR THE NEXT
WEEK WITH CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUING.
FLOOD ADVISORIES CONTINUE FOR THE SOUTH PLATTE RIVER IN LOGAN AND
SEDGWICK COUNTIES IN EXTREME NORTHEAST COLORADO.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KRIEDERMAN
LONG TERM....BAKER
