Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 020924
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
324 AM MDT TUE SEP 2 2014

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 323 AM MDT TUE SEP 2 2014

GENERALLY WESTERLY FLOW CONTINUES TODAY AS THE JET STREAM STAYS
OVER THE AMERICAN/CANADIAN BORDER. INTERESTINGLY...THE NAM12 AND
GFS ARE BOTH PUTTING A SMALL CONVECTIVE BULLSEYE OVER THE SAN
JUANS THIS AFTERNOON INTO THE EARLY EVENING HOURS. NAM12 H7 WINDS
SHOWS SOME CONVERGENCE OVER THE SAN JUANS EVEN THOUGH WINDS ARE
VERY LIGHT THROUGH THE PERIOD WHILE GFS KEEPS WESTERLY WINDS IN
THE PICTURE. WOULD NORMALLY DISCOUNT THIS SOLN BUT WITH BOTH
MODELS IN SUCH GOOD AGREEMENT...IT`S POSSIBLE ENOUGH FAVORABLE
OROGRAPHICS WILL OCCUR FOR VERY ISOLD SHOWER/QUICK STORM OVER
SMALL PORTION OF THE SAN JUANS. ASIDE FROM THAT...PLENTY OF SUN
TODAY WITH TEMPERATURES A FEW DEGREES WARMER THAN YESTERDAY WITH
SOME GUSTY AFTN WINDS FOR MAINLY NORTHERN PORTIONS OF THE CWA.

TONIGHT AND WEDNESDAY...ZONAL FLOW SETS UP ACROSS THE CENTER OF THE
CONUS BY THIS EVENING AS THE TROUGH CURRENTLY IN THE CENTER OF
COUNTRY...SWINGS INTO THE NORTHEAST STATES. WATER VAPOR/GOES
DERIVED IMAGERY SHOWS FAIRLY DRY CONDITIONS OFF THE WEFT COAST
WITH RAOBS SHOWING PWATS ALL BELOW NORMAL ACROSS THE INTERIOR
WEST. MOISTURE IS CURRENTLY WELL TO THE SOUTH OVER THE SOUTHERN
BAJA/SIERRA MADRE REGION WHERE CONVECTION REMAINS ACTIVE EARLY
THIS MORNING. EXPECT CLEARING AGAIN OVERNIGHT ALONG WITH A LARGE
DIURNAL SWING IN TEMPERATURES WEDNESDAY. LOW PRESSURE DEEPENS FROM
THE NORTHERN ROCKIES TO THE OFFSHORE WATERS OF NORTHERN CALI. THE
BACKING WINDS ALOFT AND AN APPROACHING FRONT TO OUR NORTH SHOULD
FOCUS THE THERMAL RIDGE OVER THE GREAT BASIN AND HIGHS WILL BE
RUNNING SOME 5 TO 10 DEGREES ABOVE NORMAL. A THIN RIBBON OF
MOISTURE OVER THE NORTHERN UTAH MOUNTAINS MAY POP SOME ISOLATED
SHOWERS BUT CONFIDENCE NOT HIGH ENOUGH FOR A MENTION YET.

.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 323 AM MDT TUE SEP 2 2014

WEDNESDAY NIGHT INTO THURSDAY...LOW PRESSURE CONTINUES TO DEEPEN IN
THE WEST AND THIS FORCES THE SUBTROPICAL HIGH BACK INTO THE GULF
STATES. THIS WILL ALLOW MONSOONAL MOISTURE TO ROTATE AROUND THE
PERIPHERY OF THE HIGH UP INTO SOUTHERN COLORADO. ALL MODELS BRING A
SHEARING WAVE THROUGH THE FLOW AND THE TRAILING EDGE OF THE UPPER
JET SAGS INTO OUR NORTHWEST CWA. PWATS MAY APPROACH 3/4 OF AN INCH
IN OVER THE SOUTHERN COLORADO ZONES NEAR THE MOSITURE TAP WITH
THE REMAINDER OF THE REGION STAYING NEAR HALF OF AN INCH. THERE
SHOULD BE AN UPTICK IN THUNDERSTORM ACTIVITY IN THE AFTERNOON BUT
INSTABILITY IS MODEST...FAVORING THE TERRAIN TO FOCUS THE
CONVECTION. TEMPERATURES REMAIN ABOVE NORMAL BUT SHOULD BE
DROPPING BACK JUST A TAD WITH THE ADDED MOISTURE IN PLACE.

AN UNSETTLED PERIOD ON TAP FOR REMAINDER OF THE LONG-TERM PERIOD
AS MOISTURE STARTS INCREASING FROM THE SOUTH. ACCORDING TO
GFS...PWATS WILL INCREASE TO ABOUT .7 INCHES FOR MOST OF THE
CWA EXCEPT NEAR FOUR CORNERS WHICH WILL SEE NEAR TO .9 INCHES. BY
SUNDAY...HIGH PRESSURE WILL MOVE OVER THE TX PANHANDLE ALLOWING A
MORE ROBUST SHOT OF MOISTURE TO ADVECT NWRD WITH PWATS REACHING 1
INCH SUNDAY INTO MONDAY MORNING BEFORE DROPPING BACK DOWN MONDAY
AFTN AS AN UPPER LEVEL TROUGH SHUTS OFF THE MOISTURE. AS FAR AS
PRECIP GOES...ISOLD/SCT SHOWERS AND STORMS POSSIBLE EACH
AFTN/EVENING WITH INCREASING COVERAGE SUNDAY INTO MONDAY DUE TO
INCREASED MOISTURE...AN APPROACHING TROUGH...AND AN 80KT JET
STREAK THAT IS PROGGED TO MOVE OVER NRN PORTIONS OF THE CWA.

BLENDED FORECAST TEMPS WERE SEVERAL DEGREES BELOW NORMAL WHICH
SEEMED A BIT OFF AS H7 TEMPS AND THICKNESSES NOT SHOWING THAT MUCH
CHANGE FROM DAY TO DAY. BUMPED UP TEMPS SEVERAL DEGREES TO GET
THEM CLOSER TO NORMAL FOR THIS TIME OF YEAR BUT STILL MAY BE A WEE
BIT COOL.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 323 AM MDT TUE SEP 2 2014

SUNSHINE ON TAP TODAY WITH A POSSIBLE QUICK SHOWER/STORM OVER THE
SAN JUANS THIS AFTN. EVEN SO...NO TAF SITES WILL BE AFFECTED.
GUSTY AFTN WINDS POSSIBLE...MAINLY UP NORTH. VFR CONDITIONS
CONTINUE FOR NEXT 24 HOURS.

&&

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

&&

$$

SHORT TERM...TGR/15
LONG TERM...15/TGR
AVIATION...TGR



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