000 FXUS65 KGJT 120143 AAA AFDGJT AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 743 PM MDT SUN MAY 11 2008 .UPDATE...WINDS HAVE DIMINISHED ACROSS WEST CENTRAL COLORADO THIS EVENING AND RELATIVE HUMIDITY VALUES HAVE STARTED TO IMPROVE. AS A RESULT...THE RED FLAG WARNING FOR ELEVATIONS BELOW 7000 FEET IN WEST CENTRAL COLORADO WILL BE ALLOWED TO EXPIRE AT 8 PM MDT THIS EVENING. && .SHORT TERM...TONIGHT THROUGH TUESDAY... BIG CHANGE IN THE WEATHER MONDAY AS A STORM SYSTEM AND ASSOCIATED COLD FRONT MOVE INTO THE AREA. MODELS HAVE BEEN PRETTY CONSISTENT IN THE HANDLING OF THIS SYSTEM WITH SIMILAR TIMING OF THE FRONT AND PRECIPITATION AMOUNTS. USED A BLEND OF THE WRF/NAM AND GFS FOR THIS FORECAST PACKAGE. AN UPPER RIDGE PROVIDING DRY AND WARM TEMPERATURES TODAY WILL QUICKLY MOVE EAST OF THE AREA TONIGHT WITH A COLD FRONT MOVING INTO NORTHEAST UTAH AND FAR NORTHWEST COLORADO AROUND DAYBREAK MONDAY. THE FRONT WILL THEN MOVE ACROSS THE INTERSTATE 70 CORRIDOR EARLY TO MID AFTERNOON REACHING THE FOUR CORNERS MONDAY EVENING. MODELS CONTINUE TO INDICATE DRY LOW LEVELS IN STRONG SOUTHWEST FLOW AHEAD OF THE FRONT WITH PRECIPITATION RIGHT ALONG AND BEHIND THE FRONT. IN ADDITION TO STRONG LOW LEVEL FORCING ALONG THE FRONT GOOD UPPER LEVEL JET SUPPORT IS PROGGED OVER THE AREA MONDAY NIGHT. THE MID LEVEL LOW CENTER IS EXPECTED TO TRACK ACROSS THE FOUR CORNERS VICINITY TUESDAY MORNING WITH MOISTURE WRAPPING AROUND THE LOW THROUGH TUESDAY AFTERNOON ESPECIALLY ACROSS THE CENTRAL AND SOUTHERN MOUNTAINS. SNOW LEVELS WILL FALL TO HIGHER VALLEY FLOORS MONDAY NIGHT AND EARLY TUESDAY MORNING WITH HEAVY SNOWFALL EXPECTED ACROSS MUCH OF THE MOUNTAINS. ALTHOUGH FORECAST AMOUNTS ARE ADVISORY LEVEL...THIS IS A LATE SEASON STORM AND WARRANTS A WINTER STORM WATCH FOR THE HIGHER MOUNTAINS OF WESTERN COLORADO MONDAY NIGHT THROUGH TUESDAY. FOLLOWING SHIFTS MAY NEED TO CONSIDER SOME WINTER HIGHLITES FOR THE EASTERN UINTA MOUNTAINS AND SOME OF THE HIGH PLATEAUS. PORTIONS OF THE CENTRAL AND UPPER YAMPA RIVER BASIN LIKELY TO PICK UP ACCUMULATING SNOWS AS WELL BUT HARD TELLING HOW MUCH WILL ACCUMULATE TAKING IN ACCOUNT WARM GROUND AND MELTING. .LONG TERM...TUESDAY NIGHT THROUGH SUNDAY... THE STORM SYSTEM WILL BE EXITING THE REGION TUESDAY LEAVING LINGERING SHOWERS OVER THE MOUNTAINS ALONG THE DIVIDE. THE NEXT DISTURBANCE SLIDES THROUGH THE NORTHWESTERLY FLOW ALOFT AND OVER EASTERN UT AND WESTERN CO BY WEDNESDAY. SHOWERS WILL INCREASE AGAIN WEDNESDAY INTO WEDNESDAY NIGHT ESPECIALLY OVER THE NORTHERN AND CENTRAL MTNS. THE WESTERN EDGE OF THE TROUGH DIGGING SOUTH FROM CENTRAL CANADA TRACKS OVERHEAD LATE WEDNESDAY AND EARLY THURSDAY. A RIDGE OF HIGH PRESSURE STARTS TO AMPLIFY OVER THE WESTERN US BY MID WEEK. THE RIDGE AXIS REMAINS WEST OF THE CWA KEEPING NORTHWESTERLY TO NORTHERLY FLOW ALOFT THROUGH THE END OF THE WEEK. THE RIDGE CENTER WILL RETROGRADE SLIGHTLY WEST ALTHOUGH MODELS INDICATE THAT THE NORTHERN PORTION OF THE RIDGE AXIS WILL TRANSLATE OVERHEAD AS THE NEXT TROUGH MOVES INLAND OVER THE PAC NORTHWEST. THIS SOLUTION WOULD RESULT IN WARMING TEMPERATURES ABOVE NORMAL. && .AVIATION... VFR CONDITIONS TO PREVAIL LATE THIS AFTERNOON AND TONIGHT WITH 10 TO 20 KNOT SURFACE WINDS FROM THE WEST LATE THIS AFTERNOON. INCREASING SOUTHWEST FLOW WILL YIELD STRONG GUSTY WINDS MONDAY AHEAD OF A COLD FRONT. SEE SHORT TERM PORTION OF DISCUSSION FOR TIMING OF FRONT. RAIN AND SNOW SHOWERS EXPECTED TO DEVELOP IN THE KVEL VICINITY BY 12Z MONDAY...ESPECIALLY OVER THE MOUNTAINS. CONDITIONS DETERIORATING FROM NORTHWEST TO SOUTHEAST ACROSS THE AREA THROUGH THE DAY MONDAY AS THE COLD FRONT MARCHES SOUTHEAST ACCOMPANIED BY SHOWERS AND A FEW THUNDERSTORMS. && FIRE WEATHER... MONDAY: FIRE WEATHER CONCERNS FOR WEST-CENTRAL CO HINGE COMPLETELY ON THE PROGRESS OF THE COLD FRONT. CURRENTLY...EXPECT FRONTAL PASSAGE ACROSS CO FWX ZONE 203 TOWARD 3 PM. FRONT WILL BE PRECEDED BY GUSTY WINDS AND LOWER RH AND 203 COULD HIT RED FLAG CRITERIA AROUND NOON... BUT DO NOT BELIEVE DURATION WILL BE MET DUE TO ONSET OF AFTERNOON CLOUDS FOLLOWED BY COLDER TEMPS AND RISING HUMIDITY WITH FRONTAL PASSAGE. THUS...WILL CANCEL THE FIRE WEATHER WATCH FOR ZONE 203 WITH NO HIGHLIGHTS THERE FOR MON. SOUTHWEST CO ZONE 207 A DIFFERENT STORY. FRONT NOT EXPECTED TO GET TO THE FOUR CORNERS UNTIL EVENING...SO THIS AREA SHOULD HAVE GUSTY AND DRY PREFRONTAL CONDITIONS THROUGHOUT THE AFTERNOON. WILL UPGRADE THE FIRE WEATHER WATCH TO A RED FLAG WARNING FOR ZONE 207 BELOW 7000 FT ELEVATION MONDAY FROM 11 AM UNTIL 7 PM. .GJT WATCHES/WARNINGS/ADVISORIES... .CO...RED FLAG WARNING MONDAY 11 AM TO 7 PM FOR SOUTHWEST COLORADO FIRE ZONE 207 BELOW 7000 FEET FOR GUSTY WINDS AND LOW RH. WINTER STORM WATCH MONDAY NIGHT AND TUESDAY FOR MOST OF THE MOUNTAINS...INCLUDING ZONES 4/9/10/12/13/18/19 .UT...NONE. $$ UPDATE.........JDC SHORT TERM.....TAL LONG TERM......AS AVIATION.......TAL FIRE WEATHER...JAD