FXUS65 KGJT 142100
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
300 PM MDT SUN MAR 14 2010

.SHORT TERM...TONIGHT THROUGH TUESDAY...
CLOSED LOW HAS SHIFTED TO NORTHWEST NEW MEXICO...BUT HAS IMPACTED
MUCH OF OUR FORECAST AREA TODAY. MOST OF THE PCPN HAS BEEN LIMITED
TO THE SRN HALF...OR WEST AND SOUTH OF THE GRAND MESA. BUT FOR
AREAS THAT HAVE NOT SEEN MUCH OR ANY PCPN LIKE VERNAL...EAGLE...
AND GUNNISON...GUSTY NORTHEAST WINDS HAVE BEEN A FACTOR.

PCPN AND WIND WILL QUICKLY DIMINISH THIS EVENING. MODELS INDICATE
THAT THE CLOSED LOW WILL BE FILLING AS IT DRIFTS SOUTH SOUTHEAST OVER
WRN NEW MEXICO...AND THIS IS BECOMING EVIDENT ON SATELLITE IMAGES.
MOISTURE IS NOT TIGHTLY AS WRAPPED AROUND THE CLOSED LOW AS SEVERAL
HOURS AGO...AND THE UPPER LEVEL DIVERGENCE AND COOLING CLOUD TOPS
DOES NOT HAVE THE SAME DEFINITION. LOW LEVEL CONVERGENCE REMAINS
ALIGNED WITH THE SRN UNCOMPAHGRE PLATEAU TO THE LA SAL MOUNTAINS...
BUT WITH LESS VIGOR. THE HEAVIEST SNOWFALL TODAY HAS FALLEN OVER THE
UNCOMPAHGRE PLATEAU...PLUS THE VALLEY AREAS OF SAN MIGUEL..DOLORES...
AND MONTEZUMA COUNTIES. A LOW END WARNING COULD BE HOISTED FOR THESE
VALLEY AREAS...BUT WITH SNOW TAPERING OFF WITH NOT MUCH ADDITIONAL
WIDESPREAD ACCUMULATIONS EXPECTED...CURRENT HIGHLIGHTS SHOULD BE
SUFFICIENT. ANOTHER MOISTURE SURGE CIRCULATING NORTHWARD SHOULD
AFFECT THE SAN JUAN MOUNTAINS AND THE FOOTHILLS IN LA PLATA AND
ARCHULETA COUNTIES THIS EVENING BEFORE THE SNOW ENDS LATER THIS
EVENING. WITH WINDS SUBSIDING AND PARTIAL CLEARING DURING THE
OVERNIGHT HOURS...PATCHY FOG SHOULD DEVELOP MONDAY MORNING FOR THE
VALLEY AREAS THAT RECEIVED A MIXTURE OF RAIN AND SNOW TODAY.

MONDAY AND TUESDAY...DRIER NORTHERLY FLOW TAKES OVER ON MONDAY AS
UTAH AND COLORADO WILL BE BETWEEN THE UPSTREAM RIDGE AND DOWNSTREAM
CLOSED LOW. HOWEVER THE NAM AND GFS SHOWS SOME SHALLOW POTENTIAL
INSTABILITY ALONG THE DIVIDE...SO HAVE KEPT SLIGHT CHANCE POPS FOR
THE SRN AND CENTRAL COLORADO MOUNTAINS FOR MONDAY AFTERNOON.
UPSTREAM RIDGE AXIS TRANSLATES ACROSS UTAH ON TUESDAY FOR GENERALLY
SUNNY CONDITIONS FOR THE FORECAST AREA.

.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY...

MODELS IN DECENT AGREEMENT ON THE LARGE-SCALE EVOLUTION OF A TROUGH
REPLACING THE PERSISTENT LONGWAVE RIDGE OVER THE CENTRAL USA...BUT
AS USUAL...DIFFER IN THE DETAILS. HOWEVER...FEEL MODELS ARE CLOSE
ENOUGH TO BEGIN TO ADD SOME DIFFERENTIATION TO THE DAILY FORECASTS
FOR THE LAST HALF OF THE WEEK. BEST CHANCE OF PRECIP LOOKING LIKE THU
NIGHT AND FRI RIGHT NOW.

DRY AND MILD SPRINGTIME WEATHER EXPECTED FOR WED UNDER THE INFLUENCE
OF AN UPPER RIDGE. TEMPS NEAR TO ABOVE NORMAL WED. MOSTLY CLEAR SKIES
TUE NIGHT AND WED NIGHT SHOULD FAVOR RADIATIONAL COOLING...ESPECIALLY
WHERE SNOW COVER REMAINS...SO THESE NIGHTS WILL STILL BE ON THE COOL
SIDE.

RIDGE SLIDES EAST THU AS A SHORTWAVE TROUGH DROPS OUT OF THE PACIFIC
NW...BRINGING A COLD FRONT ACROSS OUR AREA THU NIGHT. UNSETTLED NW
FLOW PERSISTS FRI AS THE UPPER TROUGH PASSES. BUMPED UP THE CHANCE OF
PRECIP THU NIGHT AND FRI AS A RESULT. COOLER NW FLOW EXPECTED FRI-SAT
FOR A DIP IN TEMPS. LARGER DIFFERENCES BETWEEN GFS AND ECWMF MODELS
POST-TROUGH FOR THE WEEKEND...BUT BOTH STILL INDICATING A DRYING
TREND SAT-SUN AS THE TROUGH MOVES EAST WITH RIDGING OVER THE FAR
WEST.

&&

.AVIATION...
MVFR CIGS WILL IMPROVE TO VFR THIS EVENING AS WIDESPREAD PCPN
BECOMES SCATTERED THIS EVENING AND ISOLATED OVERNIGHT. EXPECT AREAS
OF FOG TO FORM IN THE CENTRAL AND SOUTHERN VALLEYS PRODUCING POCKETS
OF IFR VSBY AND CIGS LATE TONIGHT AND MONDAY MORNING. VFR CONDITIONS
RETURN MONDAY AFTERNOON REGION WIDE AND ARE EXPECTED CONTINUE THROUGH
THE MIDDLE OF THE COMING WEEK.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR
ZONES 018-019-022-023.
WINTER WEATHER ADVISORY UNTIL 6 PM MDT THIS EVENING FOR
ZONES 003-009-017-020-021.
UT...WINTER STORM WARNING UNTIL 6 PM MDT THIS EVENING FOR
ZONES 025-028.

&&

$$

SHORT TERM...PF
LONG TERM....JAD
AVIATION.....NL/PF

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