000 FXUS65 KGJT 032050 AFDGJT AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 250 PM MDT FRI JUL 3 2009 .SHORT TERM DISCUSSION...TONIGHT THROUGH SUNDAY... MOIST AIR REMAINS ACROSS THE FORECAST AREA TODAY AS EVIDENCED BY SFC DEWPOINTS OF 45-55 DEGS F. AND GOES SOUNDER ESTIMATING PRECIPITABLE WATER VALUES OF 0.70 TO 1.00 INCH. SCATTERED THUNDERSTORMS DEVELOPED ACROSS PORTIONS OF NW AND WEST CENTRAL CO EARLY THIS AFTERNOON... MAINLY BETWEEN HIGHWAY 40 AND HIGHWAY 50...AHEAD OF A WEAK UPPER DISTURBANCE MOVING EAST. ANTICIPATE COVERAGE TO CONTINUE INCREASING ACROSS THE N THIS AFTERNOON AS DAYTIME HEATING AND WEAK COLD ADVECTION ALOFT OVERCOME ANY TEMPORARY SUBSIDENCE BEHIND THIS DISTURBANCE. THUNDERSTORMS ALSO STARTING TO DEVELOP IN SE UT AND SW CO PER 20Z RADAR IN THE MOIST AND UNSTABLE AIR. MODELS INDICATE SOME WEAK ENERGY MAY SHEAR NEWD FROM AZ ACROSS THIS AREA LATER TODAY...SO EXPECT SHOWERS/T-STORM COVERAGE TO CONTINUE INCREASING THERE ALSO. MAIN STORM THREAT EXPECTED TO BE HEAVY RAIN...AND SECONDARILY HAIL. STORMS ARE MOVING BUT LOCALIZED SMALL STREAM FLOODING POSSIBLE ESPECIALLY IN THOSE AREAS THAT RECEIVED SUBSTANTIAL RAINFALL THE PAST DAY OR TWO OR WHERE STORMS EXHIBIT TRAINING. EXPECT CONVECTION TO DIMINISH LATER TONIGHT AS DISTURBANCES MOVE EAST. THE UPPER HIGH OVER TX TODAY SHIFTS WESTWARD WHICH SHOULD DISRUPT ANY FURTHER INCREASE IN MOISTURE FROM THE SOUTH AND STORMS OVER NW MEXICO. BUT...DO NOT SEE ANY SIGNIFICANT DRYING THIS WEEKEND AS MODELS KEEP THE PRECIPITABLE WATER VALUES ABOVE .50 INCH IN WESTERLY FLOW SAT AND SUN. ENTRANCE REGION OF 60-70 KT 250 MB UPPER JET MOVES OVERHEAD AND COULD PROVIDE A BIT BETTER SHEAR AND DIVERGENCE FOR STRONGER STORM DEVELOPMENT. THEREFORE...EXPECT SCATTERED SHOWERS AND THUNDERSTORMS EACH DAY THIS WEEKEND ESPECIALLY OVER THE HIGHER TERRAIN. WILL GO A FEW DEGS BELOW MOS HIGH TEMPS DUE TO CLOUDS. .LONG TERM...SUNDAY NIGHT THROUGH FRIDAY... SUNDAY NIGHT AND MONDAY...DIURNALLY DRIVEN CONVECTION FROM SUNDAY AFTERNOON AND EVENING MAY CONTINUE INTO THE OVERNIGHT HOURS OVER THE HIGHER TERRAIN...PARTICULARLY THE SOUTHERN COLORADO MOUNTAINS WHERE THE BEST MOISTURE APPEARS TO REMAIN IN PLACE. OTHERWISE...EXPECT MOST ACTIVITY TO DIMINISH BY MIDNIGHT. LATE SUNDAY NIGHT AND MONDAY...A TROUGH OVER THE EASTERN PACIFIC MOVES INLAND OVER THE PACIFIC NORTHWEST. THIS FORCES A SHORTWAVE RIDGE TO AMPLIFY OVER THE CENTRAL ROCKIES. WITH PW VALUES REMAINING AT OR ABOVE 0.5 INCH ON MONDAY...THIS SHOULD BE ENOUGH TO SPARK DIURNAL LATE DAY CONVECTION OVER THE MOUNTAINS. OTHERWISE IN RESPONSE TO THE RIDGING...KEPT A MAINLY DRY FORECAST WITH WARMER TEMPS. TUESDAY THROUGH FRIDAY...MOST RECENT MODELS AGREE WITH KEEPING A MEAN TROUGH PATTERN POSITIONED OVER THE PACIFIC NORTHWEST WITH HIGH PRESSURE OVER THE DESERT SOUTHWEST AND CENTRAL PLAINS STATES. THIS KEEPS THE FORECAST AREA IN A DRY SOUTHWEST FLOW THROUGH THE WEEK. THE STRONGER GRADIENT FLOW REMAINS NORTH OF THE AREA...BUT WILL BRUSH ACROSS NORTHWEST PORTIONS OF THE CWA WHICH MAY PROVIDE SOME BREEZY CONDITIONS. THE GFS HINTS AT SOME MOISTURE RETURNING LATE IN THE PERIOD...BUT FOR NOW CONTINUED THE DRY FORECAST WITH ABOVE NORMAL TEMPERATURES THROUGH THE END OF THE WEEK. && .AVIATION... SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS EXPECTED THROUGH 03Z THIS EVENING THEN DECREASING TO ISOLATED COVERAGE BY 06Z. MVFR CIGS AND VSBYS LIKELY IN SOME OF THE HEAVIER THUNDERSTORMS...WITH LOCAL IFR CONDITIONS POSSIBLE. SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS EXPECTED THROUGH THE WEEKEND. && .GJT WATCHES/WARNINGS/ADVISORIES... .CO...NONE. .UT...NONE. $$ SHORT TERM...JAD LONG TERM....MCS AVIATION.....JAD