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