Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 180930
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
330 AM MDT THU SEP 18 2014

.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 320 AM MDT THU SEP 18 2014

HIGH PRESSURE CENTERED OF THE CENTRAL ROCKIES WILL BE SHIFTING
EAST THIS AFTERNOON AS APPROACHING PACIFIC WAVE SPITS TO OUR WEST.
SOUTHERN ENERGY CLOSES OFF ALONG THE SOUTHERN CALIFORNIA COAST
WHILE NORTHERN BRANCH OF THE SPLIT MAKES SLOW PROGRESS EAST ACROSS
THE NORTHERN ROCKIES. LITTLE IMPACT FROM EITHER OF THESE SYSTEMS
FOR OUR AREA TODAY WITH ONLY ISOLATED MOUNTAIN CONVECTION AGAIN
EXPECTED. TEMPS WILL REMAIN ABOVE NORMAL WITH INCREASING SOUTHWEST
WSW FLOW LATE IN THE DAY..RESULTING IN A FEW STRONGER GUSTS THIS
AFTERNOON.

MODELS CONTINUE TO DOWNPLAY THE AMOUNT OF MOISTURE THAT WILL
SPREAD INTO OUR AREA FROM THE REMNANTS OF ODILE. WHILE SOME
FINALLY MAKES IT INTO THE AREA ON FRIDAY...IT REALLY HAS TO TAKE A
ROUND-ABOUT ROUTE TO GET HERE AROUND THE HIGH PRESSURE CENTER THAT
WILL HAVE SHIFTED TO OUR EAST. ADDED TO THE SOUTHERLY MOISTURE
WILL BE MOISTURE ASSOCIATED WITH A WEAK WAVE THAT WILL BRUSH THE
NORTH. THE NAM INDICATES THAT PWAT VALUES PEAK AROUND ONE INCH ON
FRI...WHICH IS FAR LESS THAN WHAT WAS EXPECTED SEVERAL DAYS AGO
FOR THIS EVENT. HAVE TWEAKED POPS DOWNWARDS A TAD OVERNIGHT...AND
A LITTLE ON FRIDAY DUE TO MODEL QPF AND GUIDANCE NUMBERS WHICH ARE
MOSTLY IN THE SINGLE DIGITS.

.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 320 AM MDT THU SEP 18 2014

A HIGH PRESSURE RIDGE BUILDS OVER THE AREA FRIDAY NIGHT AND
SATURDAY...WITH A STRONG CUT OFF LOW OVER THE SOUTHERN CA COAST.
THIS WILL KEEP US MOSTLY ON THE DRY SIDE. HOWEVER MOISTURE WILL
BEGIN TO CREEP UP FROM THE SOUTH SATURDAY AFTERNOON AHEAD OF THE
LOW AS IT BEGINS TO SHIFT INLAND. THEREFORE WILL SEE A CHANCE OF
AFTERNOON AND TERRAIN BASED SHOWERS AND THUNDERSTORMS...MOSTLY
OVER THE SOUTHERN MOUNTAINS.

UNSETTLED PATTERN BEGINS IN EARNEST SUNDAY AFTERNOON AS THE
CALIFORNIA LOW PRESSURE SYSTEM LIFTS SLOWLY EAST NORTHEAST INTO
THE GREAT BASIN. INCREASINGLY DIFLUENT FLOW COMBINED WITH GENERAL
OROGRAPHIC LIFT FROM HIGHER TERRAIN IN SOUTHWEST PATTERN AND DEEP
SUBTROPICAL MOISTURE LIFTING BACK NORTH ALL POINT TO A FAIRLY
WIDESPREAD RAINFALL EVENT. SLOW MOVEMENT ADVERTISED BY MODELS
WOULD ALLOW JUST ABOUT THE ENTIRE FORECAST AREA TO SEE SOME
PRECIPITATION BY LATE TUESDAY. WITH PRECIPITABLE WATER VALUES
RUNNING AOA AN INCH FROM LATE SUNDAY INTO THE DAY ON MONDAY...A
FEW AREAS COULD SEE HEAVY RAINFALL...BUT SOME QUESTION AS TO HOW
FAST THIS LOW WILL KICK OUT...WHICH WILL PLAY HAVOC WITH TIMING.
FOR NOW...WILL CONTINUE TO RAMP UP POPS LATE THIS WEEKEND AND INTO
EARLY NEXT WEEK.

THE STORM RESPONSIBLE FOR KICKING THE SOUTHERN CALIFORNIA LOW OUT
AND ACROSS OUR REGION WILL FILL IN BEHIND THIS EXITING LOW LATE IN
THE WEEK...PROMISING MORE UNSETTLED WEATHER LATE NEXT WEEK...OR
JUST OUTSIDE THIS EXTENDED FORECAST.

TEMPS WILL BE COOLING BACK TO SLIGHTLY BELOW SEASONAL NORMS BY
EARLY NEXT WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 320 AM MDT THU SEP 18 2014

ISOLATED SHOWERS AND THUNDERSTORMS WILL DEVELOP AFTER 18Z AND
LINGER THROUGH 02Z THIS EVENING BEFORE DISSIPATING. GUSTY OUTFLOW
WINDS TO 40KTS...SMALL HAIL AND BRIEF HEAVY RAIN WILL ACCOMPANY
THE STORMS. A FEW STORMS MAY DRIFT INTO THE VCNTY OF KTEX AND
KDRO. OTHERWISE...VFR CONDITIONS PERSIST THROUGH FRIDAY MORNING.

&&

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

$$

SHORT TERM...JDC/EH
LONG TERM...EH/JDC
AVIATION...JDC



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