Area Forecast Discussion
Issued by NWS Grand Junction, CO

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS65 KGJT 220358
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
958 PM MDT THU AUG 21 2014

.SHORT TERM...(TONIGHT THROUGH FRIDAY NIGHT)
ISSUED AT 305 PM MDT THU AUG 21 2014

AN UPPER CLOSED LOW OVER SOUTHERN CA CONTINUES TO DIRECT MID AND
UPPER LEVEL MOISTURE AND CLOUDS OVER THE AREA...COMBINING
MOISTURE FROM TROPICAL STORM LOWELL AND THE NORMAL MONSOONAL
PLUME. THIS CLOUD COVER HELD DOWN CONVECTION TODAY AND WILL
CONTINUE TO DO SO OVERNIGHT. THE ONLY STORM DEVELOPMENT HAS
OCCURRED ON THE PERIPHERY OF THE HIGHER CLOUD COVER...OVER NE UTAH
AND NW CO. SOME CHANGES ARE EXPECTED LATE TONIGHT.

A SHORTWAVE WILL EJECT OUT OF THE CA LOW AS IT MOVES EAST TO SW
AZ LATE TONIGHT AND FRI MORNING. THIS MOISTURE SHOULD SPREAD
PRECIP INTO THE FOUR CORNERS BETWEEN 06Z AND 09Z...AND THEN PUSH
IT FURTHER NORTH INTO CENTRAL CO BY SUNRISE FRIDAY. THE NAM12
SHOWS THE LOW CENTER FILLING AND MOVING OVER THE FOUR CORNERS AS
AN OPEN WAVE FRIDAY AFTERNOON. PRECIP COVERAGE SHOULD INCREASE
THROUGHOUT THE DAY...WITH STRONG CONVECTION POSSIBLE OVER NE UT AND
NW CO WHICH WILL EXPERIENCE MORE SHEAR ALOFT AND LIFT FROM AN
APPROACHING PAC NW TROUGH. FRIDAY NIGHT THE TROUGH APPROACHING
FROM THE NW BECOMES THE DOMINANT FEATURE WITH A SIGNIFICANT BAND
OF PRECIP POSSIBLY FORMING OVER NE UTAH AFTER 06Z.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 305 PM MDT THU AUG 21 2014

SATURDAY WILL BE AN ACTIVE DAY FOR NORTHERN UTAH AND COLORADO. AN
UPPER LEVEL SHORTWAVE COUPLED WITH A 70 KT JET STREAK WILL PASS
EAST ACROSS THE WY/UT/CO BORDER THROUGH MIDDAY. THE LATEST MODELS
BRING THE MAIN AREA OF PRECIPITATION TO THE UT/CO BORDER AROUND
11AM ON SATURDAY...REACHING AS FAR SOUTH AS MOAB. SHOWERS AND
THUNDERSTORMS WILL BE FAST MOVING AND PRECIPITABLE WATER WILL NOT
SEASONABLY ABNORMAL...SO AM NOT ANTICIPATING ANY FLOODING ISSUES.
THUNDERSTORMS ARE EXPECTED TO CROP UP SOUTH OF THE MAIN PERIPHERY
OF CLOUD COVER AS WELL AS A FEW EMBEDDED THUNDERSTORMS IN THE MAIN
AREA OF PRECIPITATION.

SUNDAY...CONVECTIVE ACTIVITY WILL REMAIN MAINLY ALONG THE DIVIDE
MOUNTAINS OF A SCATTERED NATURE. THE LONGWAVE PRESSURE GRADIENT
WILL BECOME VERY LIGHT BY MONDAY WHICH WILL CUT OFF THE MOISTURE
TAP TO THE REGION. ANOTHER TROUGH SWIPES BY THE NORTHERN PART OF
OUR CWA ON MONDAY NIGHT AND TUESDAY...BUT PWATS ARE FORECAST TO BE
LESS THAN ONE HALF INCH BY WEDNESDAY WHICH REALLY PUTS A DAMPER ON
THE POTENTIAL FOR ANY SIGNIFICANT SHOWERS OR THUNDERSTORMS. THE
WY/UT/CO BORDER WILL AGAIN BE IN THE HIGHEST POPS FOR THIS TROUGH
ON TUESDAY...THOUGH AT THIS TIME LESS PRECIPITATION COVERAGE IS
EXPECTED.

BOTH 12Z MODELS SUGGEST HIGH PRESSURE BUILDING OVER THE WESTERN US ON
WEDNESDAY. THIS IS A NEW SOLUTION FOR THE EC...BUT THE GFS HOLDS
STRONG TO THIS PATTERN CHANGE BY THE END OF THE WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 950 PM MDT THU AUG 21 2014

SOME SHOWERS ONGOING OVER THE SAN JUANS AND ALSO EXTREME NERN UT
WITH SOME WEAK CONVECTION MIXED IN. ANOTHER SHOT OF SHOWERS IS
POSSIBLE TOWARDS MORNING OVER THE SAN JUANS BUT DO NOT ANTICIPATE
MUCH AFFECT ON TAF SITES. FOR THE OVERNIGHT THEN...MID TO HIGH
LEVEL CIGS WILL PERSIST WITH SOME VERY ISOLD SHOWERS FROM TIME TO
TIME. STARTING AROUND 18Z TOMORROW...CONVECTION WILL FIRE DUE TO
AMPLE MOISTURE AND AN UPPER LEVEL TROUGH THAT WILL MOVE OVERHEAD.
PLENTY OF SHOWERS AND THUNDERSTORMS ARE EXPECTED AT MANY TAF SITES
AND THEY WILL LIKELY EXPERIENCE VCSH AND VCTS WITH SOME RA AND TS
POSSIBLE ON-STATION. HEAVY RAIN IS POSSIBLE AS IS SOME SMALL HAIL
AND GUSTY OUTFLOW WINDS. MVFR TO IFR WILL OCCUR DUE TO LOW VIS AND
CIGS AT TIMES. MTN OBSCURATIONS ARE ALSO EXPECTED.

&&

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

$$

SHORT TERM...CC
LONG TERM...JAM
AVIATION...TGR


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.