Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 252116
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
316 PM MDT MON AUG 25 2014

.SHORT TERM...(TONIGHT THROUGH TUESDAY NIGHT)
ISSUED AT 315 PM MDT MON AUG 25 2014

SOMEWHAT TRICKY FORECAST THIS AFTERNOON AS AN UPPER LEVEL JET
STREAK CONTINUES TO RIDE OVER THE FORECAST AREA. WATER VAPOR IMAGE
ALONG WITH 320K ISENTROPIC SFC CONTINUES TO SHOW MOISTURE
ADVECTING BOTH OFF THE PACIFIC COAST AND ALSO FROM HURRICANE
MARIE.  NORMALLY...WOULD EXPECT WIDESPREAD SHOWERS AND STORMS
UNDER THESE CONDITIONS BUT 12Z MODEL RUN HAS REALLY LOWERED
COVERAGE FROM 06Z RUN. ALSO...THE LATEST RADAR MOSAIC IS SHOWING
SOME CONVECTION ACROSS THE CWA BUT NOTHING REALLY TOO
IMPRESSIVE...YET.  THIS MORNINGS SHOWERS MOST LIKELY CREATED SOME
SUBSIDENCE THAT IS FINALLY NOW BEING OVERCOME BY DAYTIME HEATING
AND THE UPPER LEVEL SUPPORT. THE CONVECTION THAT HAS FORMED IS
MOVING AT A PRETTY GOOD CLIP SO HEAVY RAIN NOT TOO MUCH OF A
CONCERN AS OPPOSED TO SOME LARGE HAIL AND GUSTY OUTFLOW WINDS.
WITH ALL THIS IN MIND...DO EXPECT SOME CONVECTION BUT NOT UNTIL A
LITTLE LATER WITH SOME STRONG STORMS POSSIBLE.

THE BIG PICTURE CONTINUES TO SHOW AN AUTUMN-LIKE CLOSED LOW OVER
NRN NV WITH DECENT UPPER LEVEL SUPPORT DIGGING THE TROUGH
SOUTHWARD OVERNIGHT. AHEAD OF THE TROUGH...WEAK DISTURBANCES WILL
ALLOW SOME PRECIP TO CONTINUE THROUGH THE EARLY MORNING HOURS WITH
A DOWNTURN FROM ABOUT 6AM THROUGH NOON. AFTER THAT...A STRONG VORT
MAX WILL ARRIVE FROM THE SOUTHWEST WHILE PWATS REMAIN NEAR AN INCH
AIDING IN CONVECTIVE DEVELOPMENT WITH AREAS SOUTH LOOKING FAVORED
THOUGH ALL HIGHER TERRAIN WILL SEE A CHANCE FOR SOME SHOWERS AND
STORMS. THE PRECIP WILL CONTINUE INTO THE EVENING HOURS.

TEMPS WILL CONTINUE TO RUN SEVERAL DEGREES COOLER THAN NORMAL FOR
THIS TIME OF YEAR.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 315 PM MDT MON AUG 25 2014

WEDNESDAY THROUGH THURSDAY WILL BE UNSETTLED AS AN UPPER LOW
TRACKS SLOWLY ACROSS THE FORECAST AREA. WITH THE LOW CUTOFF FROM
THE POLAR JET THE SLOWER EC IS SOLUTION IS STILL FAVORED. THE LOW
MOVES INTO NE UTAH WEDNESDAY AFTERNOON...THEN OPENS AND SLOWLY
SLIDES SE OF THE FORECAST AREA BY THURSDAY. A DRY SLOT IS PROGGED
TO WORK INTO THE BASE OF THE LOW OVER SOUTHERN COLORADO ON
WEDNESDAY WITH DEEPER MOISTURE ORIGINATING FROM MARIE WRAPPING
AROUND INTO THE NORTHERN ZONES. THIS ENHANCEMENT RAKES THE
NORTHERN ZONES THROUGH WEDNESDAY NIGHT...THE CONTINENTAL DIVIDE ON
THURSDAY WITH A DRYING TREND FOR MUCH OF THE WESTERN CWA.
ASSOCIATED COLD CORE WEAKENS FORM -14C TO -11C AS IT PASSES OVER
THE CENTRAL- SOUTHERN CWA SO THE BEST MIX OF DEEP MOISTURE AND
INSTABILITY MAY BE OVER THE CENTRAL CWA. CLOUDS AND SHOWERS WILL
KEEP TEMPERATURES BELOW NORMAL. EASTERN SHOWERS ARE TIMED TO END
THURSDAY EVENING.

FRIDAY-SATURDAY HIGH PRESSURE CENTERED WEST OF SAN DIEGO ATTEMPTS
TO BUILD OVER THE REGION. BUT THE NEXT TROUGH FROM THE GULF OF
ALASKA DIGS INTO THE PACIFIC NW ON SATURDAY. THE GFS IS SLOWER TO
PROGRESS THIS TROUGH THROUGH THE NORTHERN ROCKIES WHILE THE EC
TIMES TROUGH PASSAGE ON MONDAY. EITHER SOLUTION STILL PRODUCES A
DRYING AND WARMING TREND.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1128 AM MDT MON AUG 25 2014

VISIBLE SATELLITE SHOWING SOME HIGH CLOUDS STREAMING OVER THE
SOUTHERN HALF OF THE CWA THIS MORNING WITH SOME CUMULUS BUILDING
OVER THE REMAINING HIGHER TERRAIN. AM EXPECTING CONVECTION TO GET
GOING HERE VERY SHORTLY WITH SHOWERS AND STORMS BECOMING COMMON.
MEDIUM CONFIDENCE THIS CONVECTION WILL AFFECT TAF SITES THIS AFTN
AND EVENING SO INCLUDED VCTS AND VCSH FOR MANY AERODROMES. UPPER
LEVEL WINDS WILL KEEP STORMS MOVING AT A GOOD PACE SO CONCERNS
TODAY WILL BE SOME HAIL AND GUSTY OUTFLOW WINDS. SOME SHOWERS AND
STORMS WILL PERSIST OVERNIGHT INTO TOMORROW WHEN MORE WIDESPREAD
PRECIP IS EXPECTED.


&&

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

$$

SHORT TERM...TGR
LONG TERM...JOE
AVIATION...TGR



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