Area Forecast Discussion
Issued by NWS Grand Junction, CO

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000
FXUS65 KGJT 160506
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1106 PM MDT MON SEP 15 2014

.UPDATE...
ISSUED AT 920 PM MDT MON SEP 15 2014

IN THE SHORT TERM...MODELS HINT THAT MOISTURE FROM NEW MEXICO
RETURNS TO SOUTHWEST COLORADO LATE THIS EVENING. THIS IS NOT A
PRONOUNCED MOISTURE SURGE...BUT APPEARS THAT OUTFLOWS FROM SPOTTY
STORMS OVER NW NEW MEXICO (SSE GUSTY WIND AT FARMINGTON) GETS
INTO LA PLATA AND ARCHULETA COUNTIES. THE HRRR DEPICTS SPOTTY
LIGHT PCPN OVERNIGHT...SO ELECTED TO GO THE "ISOLATED" ROUTE
INSTEAD OF "SCATTERED". FOR THE REMAINDER OF THE FORECAST AREA...
LIMITED CONVECTIVE DEBRIS IS DISSIPATING FOR MOSTLY CLEAR
CONDITIONS.

&&

.SHORT TERM...(TONIGHT THROUGH TUESDAY NIGHT)
ISSUED AT 257 PM MDT MON SEP 15 2014

H5 HAND ANALYSIS AT 12Z HAD THE RIDGE AXIS ALONG THE GREAT BASIN TO
THE FAR WESTERN CANADIAN PROVINCES. THIS RIDGE IS SQUEEZED BETWEEN
AN EXPANSIVE EASTERN TROUGH EXTENDING FROM THE ARCTIC TO THE GREAT
LAKES...AND TROUGH OFF THE WEST COAST OF NOAM. LOWER DOWN A SURFACE
COLD FRONT WAS MAKING IT/S WAY DOWN THE SOUTHERN HIGH PLAINS...BUT
STALLING NEAR THE TX/OX/NM BORDERS LATE THIS AFTERNOON. UPPER JET
MAX HAS SHIFTING EAST AND WITH MINIMAL LARGE SCALE ASCENT OVER
OUR CWA...THE CONVECTION HAS FOCUSED OVER THE HIGHER TERRAIN WITH
PARTICULAR EMPHASIS ALONG THE TAVAPUTS/ROAN PLATEAU AND FLAT TOPS.
NEAR TERM MODELS SUGGEST THIS CONVECTION WILL REMAIN ISOLATED
THROUGH THE EVENING BEFORE DISSIPATING AFTER SUNSET. STRONG EML
SUGGEST WINDS THE BIGGEST THREAT. BOUNDARIES FROM STORMS MAY FORCE
A SHOWER INTO A VALLEY BUT CONFIDENCE FAIRLY LOW. BEST CHANCE FOR
THIS TO OCCUR WITH CURRENT 88D TRENDS IS THE SOUTHERN SAN JUAN
FOOTHILLS AND HAVE PUSHED POPS TO ISOLATED THERE AS WELL.

THE OVERALL PATTERN WILL BE SHIFTING SLIGHTLY OVER THE NEXT 36 TO 48
HOURS AS THE EASTERN TROUGH AXIS LIFTS NORTHEAST AND LOW PRESSURE
DEEPENS OFF THE WEST COAST. THIS WILL PUSH THE RIDGE AXIS ALONG THE
SPINE OF THE ROCKIES. THE RESULT WILL TEMPERATURES WARMING A FEW
DEGREES TOMORROW AND LIMITED CONVECTION AGAIN AS THE SUBSIDENCE
INVERSION SHOULD STRENGTHEN. ONE CHALLENGE WILL BE EARLY MORNING
CONVECTION OR A POSSIBLE PUSH OF LOW CLOUDS TOWARD THE SOUTHERN
VALLEYS. HIGH PRESSURE BUILDING DOWN THE LEE OF THE ROCKIES LOOKS TO
BULGE OVER THE LOWER DIVIDE IN NEW MEXICO WITH THE SOUTHERLY RETURN
FLOW POINTED TOWARD THE 4 CORNERS. AS A RESULT...DEW POINTS
SHOULD BE INCREASING THROUGH THE EARLY MORNING HOURS OVER
CEZ/DRO/PSO. ATTM MODELS SOUNDINGS AND RH FIELDS DO NOT SHOW
STRATUS BUILDING IN...BUT THIS MOISTURE MAY SERVE TO FUEL A BIT
MORE CONVECTION IN THE SOUTHERN SAN JUANS AS MOUNTAIN
CIRCULATIONS LIFT THE MOISTURE UP THE SLOPES TOMORROW AFTERNOON.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 257 PM MDT MON SEP 15 2014

THE RIDGE AXIS IS STILL PROJECTED TO BE DIRECTLY OVER THE
FORECAST AREA AROUND NOON ON WEDNESDAY...CREATING A VERY WARM AND
PLEASANT DAY ACROSS THE REGION. A TRANSITION IN THE PATTERN WILL
BEGIN TO OCCUR THURSDAY ACROSS EASTERN UTAH AND THE FOUR CORNERS
REGION AS THE RIDGE SLIDES EAST AND GENERAL SOUTHWEST FLOW
DEVELOPS. PRECIPITABLE WATER VALUES CLIMB TO BETWEEN 0.75 INCHES
AND 1.0 INCHES THURSDAY NIGHT INTO FRIDAY ACROSS THE REGION. THE
REMNANTS OF HURRICANE ODILE ARE PROJECTED TO REACH THE NM/CO
BORDER LATE THURSDAY NIGHT BUT OTHERWISE STAY TO THE SOUTH AND
EAST OF THE FORECAST AREA.

THE DETAILS ON ACTUAL DYNAMIC FORCING MECHANISMS NEAR THE END OF
THE WEEK ARE STILL VERY FUZZY WITH FORECAST MODELS SWITCHING
SOLUTIONS ALMOST EVERY CONSECUTIVE RUN. EXPECT AN UPTICK IN
ACTIVITY AT THE END OF THE WEEK AND INTO THE WEEKEND...BUT VERY
LOW CONFIDENCE ON TIMING AND EXACT THREAT AT THIS TIME. THE LATEST
MODELS SUGGEST A BREAK IN ACTIVITY ON SATURDAY...BUT WITH
MOISTURE STILL IN PLACE THINKING THAT THIS COULD REALLY FUEL
DIURNAL ACTIVITY ON SATURDAY WITH THE ADDED BENEFIT OF BREAKS IN
THE CLOUDS. AT THIS TIME...SUNDAY AND MONDAY LOOK TO BE RELATIVELY
ACTIVE WITH DIURNAL ACTIVITY AS A TROUGH PASSES THROUGH THE GREAT
BASIN.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1103 PM MDT MON SEP 15 2014

ISOLATED SHOWERS AND THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS
AFTER 18Z WITH GUSTY WINDS TO 40 MPH...SMALL HAIL AND LOCALLY
HEAVY RAINFALL EXPECTED. A FEW STORMS MAY DRIFT INTO THE VICINITY
OF KTEX...KASE AND KDRO. OTHERWISE...VFR CONDITIONS ARE EXPECTED
TO HOLD THROUGH TUESDAY EVENING.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&

$$

UPDATE...PF
SHORT TERM...15
LONG TERM...JAM
AVIATION...JDC


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