Special Weather Statement, NWS Denver/Boulder, CO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
233 PM MDT TUE JUL 17 2012

.SHORT TERM...A WEAK WESTERLY FLOW ALOFT WILL PREVAIL THROUGH THE
EVENING AS A RIDGE RESIDES OVER THE SOUTHERN ROCKIES. DRIER AIR HAS
MOVED INTO THE AREA FROM THE WEST. THIS WILL DECREASE THE AMOUNT OF
THUNDERSTORMS TODAY. AIRMASS WILL STILL BE UNSTABLE ENOUGH AND
ENOUGH MOISTURE WILL BE PRESENT FOR SCATTERED THUNDERSTORMS THIS
AFTERNOON AND EVENING. DUE TO AN EASTERLY STORM MOTION AT 10 MPH AND
A DRIER AIRMASS...THE THREAT FOR FLASH FLOODING TODAY WILL BE LOWER.
THE CONVECTION DECREASE LATE IN THE EVENING AND SHOULD COME TO AN
END AROUND MIDNIGHT.

ON WEDNESDAY...UPPER LEVEL RIDGE WILL BE CENTERED OVER EASTERN
COLORADO. THIS WILL PRODUCE A WEAK FLOW ALOFT. AIRMASS WILL WARM AND
MOISTURE WILL INCREASE SLIGHTLY. PRECIPITABLE WATER VALUES WILL
RANGE FROM 0.65 INCHES OVER THE HIGHER TERRAIN TO AROUND AN INCH
OVER THE FRONT RANGE AND EASTERN PLAINS. CAPES WILL BE UP TO 1000
J/KG. EXPECT ANOTHER ROUND OF AFTERNOON AND EVENING THUNDERSTORMS.
MOST OF THEM WILL INITIATE OVER THE HIGH COUNTRY AND THEN SPREAD
EAST ACROSS THE FRONT RANGE. WILL BE MORE DIFFICULT FOR STORMS TO
MAKE IT ACROSS THE EASTERN PLAINS DUE TO THE WEEK WINDS ALOFT AND
WARM AIR HELPING TO CAP CONVECTION.

.LONG TERM...AN UPPER LEVEL HIGH WILL BUILD BACK OVER THE AREA BY
THU AND REMAIN OVER THE AREA THRU FRI. SOME SUBTROPICAL MOISTURE
WILL LINGER OVER THE AREA BOTH DAYS HOWEVER PRECIPITABLE WATER
VALUES WILL DECREASE FROM THU INTO FRI. BEST CHC OF STORMS WILL BE
OVER THE HIGHER TERRAIN BOTH DAYS HOWEVER COVERAGE MAY DECREASE
SOME ON FRI. OVER NERN CO TSTM CHANCES LOOK ON THE LOW SIDE AND
CONFINED CLOSER TO THE FOOTHILLS. AS FAR AS HIGHS READINGS WILL
RISE INTO THE MID TO UPPER 90S OVER NERN CO WITH 100 DEGREES
POSSIBLE OVER THE FAR NERN CORNER BOTH DAYS.

FOR THE WEEKEND THE ECMWF KEEPS THE UPPER LEVEL HIGH OVER COLORADO
WHILE THE GFS SHIFTS IT INTO KANSAS AND NEBRASKA. AS A RESULT THE
GFS SHOWS BETTER SUBTROPICAL MOISTURE MOVING BACK INTO THE MTNS IN
SSW FLOW WHILE THE ECMWF KEEPS THE BEST SUBTROPICAL MOISTURE
FURTHER WEST OVER WRN CO AND UTAH. AT THIS POINT HARD TO SAY
WHICH SOLUTION IS BEST. FOR NOW WILL KEEP A CHC OF TSTMS IN THE
MTNS BOTH DAYS. OVER NERN CO WILL ONLY MENTION A SLIGHT CHC OF
TSTMS NR THE FOOTHILLS AND KEEP THE PLAINS DRY. BASED ON LATEST
850-700 MB TEMPS HIGHS WILL RANGE FROM THE MID 90'S TO LOWER 100'S
OVER NERN CO.

BY EARLY NEXT WEEK THE UPPER LEVEL HIGH IS FCST TO BE OVER THE
CNTRL PLAINS WITH THE FLOW ALOFT BECOMING MORE SWLY. BOTH THE
ECMWF AND GFS SHOW DECENT SUBTROPICAL MOISTURE OVER THE AREA WITH
A CHC OF TSTMS OVER THE HIGHER TERRAIN WITH PRECIPITABLE WATER
VALUES ABV AN INCH. OVER NERN CO EXPECT ANOTHER HOT DAY WITH A
SLIGHT CHC OF TSTMS MAINLY NEAR THE FOOTHILLS AS THE NERN PLAINS
REMAIN CAPPED DUE TO WRM MID LVL TEMPS. HIGHS ON MON WILL LIKELY
RANGE FROM 95 TO 100 DEGREES OVER NERN CO. BY TUE A WK FNT MAY
MOVE INTO NERN CO BRINGING SLIGHTLY COOLER TEMPS ALONG WITH AN
INCREASE IN LOW LVL MOISTURE AND A BETTER CHC FOR TSTMS.

&&

.AVIATION...SCATTERED THUNDERSTORMS WILL SHIFT ACROSS THE DENVER
AREA THIS LATE THIS AFTERNOON AND EARLY EVENING. CEILINGS WILL FALL
BELOW 6000 FEET AND VISIBILITY WILL DROP BELOW 5 MILES UNDER THE
STRONGEST THUNDERSTORMS. OUTFLOW WIND GUSTS TO 30 KNOTS WILL BE
POSSIBLE WITH THE THUNDERSTORMS. OTHERWISE...VFR CONDITIONS AND
LIGHT WINDS WILL PREVAIL THROUGH TONIGHT. ANOTHER ROUND OF AFTERNOON
AND EVENING THUNDERSTORMS WILL DEVELOP WEDNESDAY.

&&

.HYDROLOGY...SCATTERED THUNDERSTORMS WILL MOVE ACROSS THE AREA
THIS AFTERNOON AND AGAIN ON WEDNESDAY. STORM MOTION TODAY WILL BE
TO THE EAST AT AROUND 10 MPH. AIRMASS IS NOT AS MOIST AS
YESTERDAY...SO THE FLASH FLOOD THREAT WILL BE LOWER TODAY. FLASH
FLOOD THREAT WILL BE SLIGHTLY HIGHER WEDNESDAY AS MOISTURE
INCREASES SLIGHTLY. STORMS WILL BE SLOWER MOVING AND THE THREAT
FOR STORMS TO REDEVELOP OVER THE SAME AREA WILL HIGHER
WEDNESDAY. THE THREAT FOR HEAVY RAIN PRODUCING THUNDERSTORMS WILL
DECREASE THURSDAY AND FRIDAY WITH A LOWER POTENTIAL FOR FLASH
FLOODING IN THE BURN SCARS.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

SHORT TERM...MEIER
LONG TERM....RPK
AVIATION...MEIER