Area Forecast Discussion
Issued by NWS Grand Junction, CO

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000
FXUS65 KGJT 172116
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
316 PM MDT SUN AUG 17 2014

.SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)
ISSUED AT 316 PM MDT SUN AUG 17 2014

TAIL END OF A SHORTWAVE TROUGH MOVING OVER MT/WY TODAY WAS JUST
ENOUGH TO SET OF THE ISOLATED STORM ACTIVITY OVER THE TAVAPUTS AND
ROAN PLATEAU EARLIER TODAY. IN ITS WAKE A BIT OF SUBSIDENCE AND
REBOUND OF UPPER LEVEL HEIGHTS IS HELPING TO RETARD DIURNALLY
DRIVEN CONVECTION. AIRMASS DRIER TODAY THAN PREVIOUS DAYS.
NONETHELESS...EXPECT ISOLATED TO SCATTERED COVERAGE OF SHRA/TSRA
THIS AFTN AND EARLY EVENING OVER THE FAVORED HIGHER
TERRAIN...DRIBBLING OVER AT TIMES ACROSS DOWNSTREAM VALLEYS.

THE CENTER OF THE UPPER LEVEL ANTICYLCONE TO OUR SOUTH WILL WEAKEN
AND SHIFT EAST IN RESPONSE TO A CLOSED LOW DROPPING SOUTH ALONG
THE WEST COAST MONDAY AND MONDAY NIGHT. AN UPPER LEVEL SHORTWAVE
WILL MOVE NORTHEAST OVER UT AND WRN CO MONDAY NIGHT AND PULL A TAP
OF 1 INCH PLUS PRECIPITABLE WATER INTO ERN UT BY TUESDAY MORNING.
WITH SOME DYNAMICS INVOLVED WITH PASSAGE OF SHORTWAVE MONDAY NIGHT
WILL KEEP RELATIVELY HIGHER CHANCE OF RAIN GOING THROUGH THE
EVENING AND NOT SHUT THINGS OFF COMPLETELY AFTER MIDNIGHT.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 316 PM MDT SUN AUG 17 2014

THE 12Z GFS CONTINUES ITS 00Z SOLUTION OF BRINGING THE PAC NW
TROUGH AND CLOSED LOW SLOWLY EAST ACROSS THE GREAT BASIN
THROUGHOUT THE MIDDLE OF THE WORK WEEK. AS THIS TROUGH PUSHES
EAST...THE HIGH PRESSURE CURRENTLY OVER THE REGION WILL SHIFT EAST
AND PULL THE MONSOONAL TAP BACK INTO THE CWA WITH PRECIPITABLE
WATER INCREASING TO OVER ONE INCH BY TUESDAY AFTERNOON. THE EC
KEEPS THE CLOSED LOW OFFSHORE OF CALIFORNIA...HOWEVER IT DOES
BRING THE TROUGH THROUGH THE REGION ON TUESDAY AS WELL. NOT
IMPRESSED WITH CONVECTIVE INDICES AT ANY POINT IN THE LONG
TERM...THOUGH LOCALLY HEAVY THUNDERSTORMS WILL STILL BE POSSIBLE
WITH DYNAMICS BEING THE DRIVING FACTOR OF CONVECTIVE DEVELOPMENT.

THE GFS SHOWS QG FORCING PRESENT LATE MONDAY NIGHT THROUGH TUESDAY
AND THEN AGAIN ON THURSDAY AND SUNDAY AS PIECES OF THE TROUGH
MOVE EAST THROUGH THE REGION. BOTH THE EC AND GFS KEPT WITH THEIR
SOLUTIONS TWO RUNS IN A ROW NOW...BUT WITH THE MODELS NOT AGREEING
ON LONGWAVE FEATURES...LOW CONFIDENCE IN THE LONG TERM. DOES LOOK
LIKE AN ACTIVE WEATHER WEEK FROM TUESDAY THROUGH THE WEEKEND WITH
SHORT BREAKS ON DAYS BETWEEN PUSHES OF ENERGY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1143 AM MDT SUN AUG 17 2014

VFR CONDITIONS EXPECTED. ISOLATED SHRA/TSRA NEAR THE INTERSTATE
70 CORRIDOR THIS MORNING WILL DIMINISH WHILE THE REMAINDER OF THE
AREA SEES THE TYPICAL AFTERNOON CONVECTIVE DEVELOPMENT OVER THE
HIGHER TERRAIN. STEERING FLOW WILL PUSH STORMS TO THE EAST
SOUTHEAST. HAVE INCLUDED VCTS AT FAVORED MOUNTAIN TAF SITES
THROUGH EARLY EVENING AND WILL WATCH FOR SHORTER TERM UPDATES.
CONVECTION WILL DIE OFF THIS EVENING AND GIVE WAY TO GENERALLY
CLEAR AND CALM CONDITIONS.


&&

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

$$

SHORT TERM...BM
LONG TERM...JAM
AVIATION...BEN


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