000
FXUS65 KGJT 142057
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
257 PM MDT FRI JUN 14 2013

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 257 PM MDT FRI JUN 14 2013

AIR MASS IS CONSIDERABLY DRIER TODAY EXCEPT FOR THE FAR SERN PORTION
OF THE FORECAST AREA.  LOW TOP CONVECTION HAS FIRED OVER THE SAN
JUAN MOUNTAINS (MOSTLY EAST OF HWY 550).  BUT LIGHTNING STRIKES HAVE
BEEN ISOLATED...WITH THE MAJORITY OF THESE DOWNSTREAM EAST OF OUR
FORECAST AREA.  ISOLATED SAN JUAN STORMS ARE DIURNALLY DRIVEN AND
WILL DISSIPATE BY SUNSET.  MOSTLY CLEAR CONDITIONS ARE EXPECTED
OVERNIGHT AND RELATIVELY WEAK DRAINAGE WINDS. IN THE UINTA BASIN...
WINDS TURN NORTHERLY (ABOUT 10 MPH) AS REMNANTS OF SHALLOW COOL
FRONT SAGS SOUTHWARD FROM WYOMING.

SATURDAY AND SATURDAY NIGHT...MID LEVEL MOISTURE FROM OLD MEXICO AND
ARIZONA GETS ADVECTED NORTHWARD INTO SERN UTAH AND SWRN COLORADO
BY AFTERNOON. THIS MOISTURE SPREADS A LITTLE FARTHER NORTH AND
REACHES THE BOOKCLIFFS AND FLAT TOP MOUNTAINS BY LATE AFTERNOON.
BOUNDARY LAYER IS DRY BUT SUFFICIENT CONVECTIVE POTENTIAL FOR
SCATTERED MOUNTAIN THUNDERSTORMS. THESE ARE HIGH BASED STORMS WITH
THIN RAIN SHAFTS...SO A MIXTURE OF DRY AND WET THUNDERSTORMS.
APPEARS THERE IS SUFFICIENT SHEAR OR MOISTURE TRANSPORT THAT A FEW
OF THESE STORMS WILL ROLL OFF THE HIGHER TERRAIN AND MOVE OVER
VALLEY LOCATIONS (ISOLATED AREAL COVERAGE). BOOSTED POPS FROM
SATURDAY NOON AND EVENING THAN PREVIOUS FORECASTS HAVE
INDICATED...BUT QPF REMAINS LOW WITH MOST STORMS PRODUCING LESS
THAN A TENTH OF AN INCH /0.10/. MOISTURE ADVECTION CONTINUES INTO
SATURDAY NIGHT...BUT THE LOSS OF THE STRONG JUNE SUNSHINE WILL
LIMIT CONVECTIVE POTENTIAL. ISOLATED STORMS MAY LAST THROUGH
MIDNIGHT WITH CONVECTIVE DEBRIS PERSISTING THROUGH THE NIGHT.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 257 PM MDT FRI JUN 14 2013

SUNDAY AND MONDAY...THE AXIS OF A BROAD RIDGE REMAINS OVER THE
ROCKIES WITH A TROUGH OFF THE WEST COAST. THIS PRODUCES A WARM
SOUTHWEST FLOW WITH MARGINAL MOISTURE THAT MAY PRODUCE
ISOLATED/SCATTERED LATE-DAY THUNDERSTORMS FAVORING THE SOUTHERN
MOUNTAINS. THESE STORMS WILL PRODUCE MORE WIND AND LIGHTNING THAN
RAIN. MORNING LOW TEMPERATURES WILL BE NEAR NORMAL WITH AFTERNOONS
ABOUT 5 DEGREES WARMER THAN NORMAL.

TUESDAY-FRIDAY...THE WEST COAST TROUGH WORKS ONSHORE AND THE RIDGE
AXIS SHIFTS ONTO THE EASTERN PLAINS. THIS LIMITS THE MARGINAL
MOISTURE AND THUS LOWERS THE CHANCES OF LATE-DAY THUNDERSTORM
COVERAGE. DAYTIME TEMPERATURES REMAIN WARM AND SW GRADIENT WINDS
WILL MIX DOWN IN THE AFTERNOONS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 257 PM MDT FRI JUN 14 2013

SKC CONDITIONS FOR MUCH OF THE REGION THROUGH 18Z SATURDAY.
ISOLATED STORMS OVER THE SAN JUAN MOUNTAINS WILL DISSIPATE BY 02Z
THIS EVENING.

AFTER 18Z SATURDAY...SCATTERED THUNDERSTORMS (MAINLY OVER THE HIGH
TERRAIN) ARE EXPECTED SOUTH OF A LINE FROM KVEL-KEEO-KEGE. ERRATIC
WIND GUSTS TO 40 KTS WILL BE POSSIBLE FROM NEARBY THUNDERSTORMS.

KDRO...KPSO...KCEZ...KTEX: THUNDERSTORMS WILL BE IN THE VICINITY
OF THESE LOCATIONS SATURDAY AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 257 AM MDT FRI JUN 14 2013

ON SATURDAY IN A WARM SW FLOW...MOISTURE INCREASES INTO THE FOUR
CORNERS. THIS WILL INCREASE THUNDERSTORM ACTIVITY IN THE SAN JUANS
AND SURROUNDING MOUNTAIN RANGES. SOME STORMS WILL PRODUCE WETTING
RAINS BUT THERE IS GOOD POTENTIAL FOR DRY LIGHTNING ALONG WITH GUSTY
OUTFLOW WINDS. THEREFORE A RED FLAG WARNING HAS BEEN ISSUED FOR ZONE
207 THROUGH SATURDAY AFTERNOON. ISOLATED DRY STORMS ARE ALSO
POSSIBLE OVER ZONES 203 290 291 292 293 AND WILL BE EVALUATED BY
TONIGHT`S FORECAST SHIFT FOR POSSIBLE INCLUSION.

SUNDAY AND MONDAY...LATE DAY STORMS WILL BE MORE ISOLATED IN
COVERAGE MAINLY OVER THE MOUNTAINS. EXPECT A DRYING TREND NEXT WEEK
AS TROUGH OF LOW PRESSURE SHIFTS FROM THE EASTERN PACIFIC INTO THE
GREAT BASIN. DAYTIME TEMPERATURES REMAIN ABOVE NORMAL WITH LOW
HUMIDITY.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...RED FLAG WARNING FROM NOON TO 8 PM MDT SATURDAY FOR COZ207.

UT...NONE.
&&

$$

SHORT TERM...PF
LONG TERM...JOE
AVIATION...PF
FIRE WEATHER...JOE