Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 212118
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
318 PM MDT TUE OCT 21 2014

.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 317 PM MDT TUE OCT 21 2014

AN INITIAL SURGE OF MOISTURE COMBINED WITH JET DIVERGENCE
CONTINUED TO GENERATE AREAS OF LIGHT SHOWERS AND A FEW EMBEDDED
THUNDERSTORMS ACROSS WESTERN COLORADO THIS AFTERNOON. MEANWHILE
...THE MAIN TROUGH WAS DRIVING A COLD FRONT ACROSS NORTHERN UTAH
AND WILL CONTINUE TO TRACK ACROSS WYOMING THIS EVENING. PASSAGE OF
THE TROUGH WILL CONTINUE TO GENERATE SCATTERED TO NUMEROUS SHOWERS
AND A FEW THUNDERSTORMS THIS EVENING. AS MENTIONED IN PREVIOUS
DISCUSSIONS...SNOW WILL FALL AT THE HIGHER ELEVATIONS WITH MODELS
INDICATING A SNOW LEVEL NEAR 10000 TO 10500 FEET. LIFT ASSOCIATED
WITH THE TROUGH PASSAGE NOT IMPRESSIVE SO ACCUMULATIONS WILL BE
LIGHT AND CONFINED TO THE PEAKS.

LINGERING MOISTURE...INSTABILITY...AND OROGRAPHIC LIFT WILL
CONTINUE TO GENERATE LIGHT SHOWERS OVER THE MOUNTAINS WEDNESDAY
BEFORE PRECIPITATION ENDS WEDNESDAY NIGHT. THE COLD FRONT STALLS
ACROSS THE NORTHERNMOST ZONES WHICH WILL BRING COOLER TEMPERATURES
THERE TONIGHT. ELSEWHERE...CAA ON THE BACKSIDE OF THE SYSTEM
COMBINED WITH FEWER CLOUDS IN THE WESTERN VALLEYS WILL BRING MORE
SEASONABLE LOWS. HIGHS WILL BE NEAR OR A LITTLE ABOVE NORMAL
WEDNESDAY...THEN COLDER WEDNESDAY NIGHT AS CLOUDS CLEAR OVER THE
AREA.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 317 PM MDT TUE OCT 21 2014

HIGH PRESSURE BUILDS OVER MUCH OF THE WESTERN AND CENTRAL US ON
THURSDAY AND KEEPS DRY WEATHER AND WARM TEMPERATURES OVER THE
REGION THROUGH SATURDAY. THE NEXT TROUGH COMES ONSHORE THE
PACIFIC NORTHWEST COAST ON SATURDAY MORNING WHICH WILL HELP TO
INCREASE THE GENERAL WINDS ACROSS EASTERN UTAH AND EXTREME
NORTHWESTERN COLORADO BY SATURDAY AFTERNOON. THERE IS CONSISTENCY
ON THIS PACIFIC NW TROUGH MOVING EAST INTO THE FORECAST AREA
SOMETIME DURING THE LATE WEEKEND INTO THE EARLY WORKWEEK...HOWEVER
THERE ARE SOME DISCREPENCIES WITH HOW FAR SOUTH THE PRECIPITATION
WILL BE ON SUNDAY INTO MONDAY. BOTH THE 12Z GFS AND EC MODELS ARE
INDICATING A TWO-PART SYSTEM...WITH THE FIRST A WEAKER DISTURBANCE
ON SUNDAY AND A SECOND PART ON MONDAY ASSOCIATED WITH A RELATIVELY
STRONG COLD FRONT. 700MB TEMPS BY MONDAY MORNING ARE FORECAST TO
BE AROUND -5C TO -7C OVER NORTHERN UT/CO AND AROUND ZERO TO -3C
OVER SOUTHERN UT/CO...WHICH WOULD BRING TEMPERATURES TO NEAR
NORMAL FOR THIS TIME OF YEAR. AM MODERATELY CONFIDENT THAT A
TROUGH WILL REACH THE AREA LATE OVER THE WEEKEND INTO MONDAY BUT
THE DETAILS MAY CHANGE AS SUBSEQUENT WX MODELS CHANGE THE TIMING
AND AMPLITUDE OF THIS SYSTEM OVER THE NEXT COUPLE OF DAYS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1107 AM MDT TUE OCT 21 2014

MOSTLY CLOUDY WITH SHOWERS SWEEPING WEST TO EAST ACROSS THE AREA
THROUGH THIS EVENING AS A COLD FRONT APPROACHES FROM THE WEST.
EVEN SO...ANTICIPATE MOST AREAS TO REMAIN VFR WITH SOME ISOLD MVFR
POSSIBLE IN THE AFTERNOON AND EVENING. ANY AREAS THAT SEE MVFR
THIS AFTERNOON NOT EXPECTED TO STAY THAT WAY EXCEPT MTNS THAT MAY
SEE A BIT MORE CLOUDS AND SHOWERS. ALL TAF SITES UNDER THE GUN BUT
AGAIN...DO NOT ANTICIPATE PROLONGED MVFR FOR ANY OF THEM. KTEX...
KASE...AND KEGE HAVE THE BEST CHANCE FOR MVFR DUE TO THEIR
LOCATION. EXPECT PRECIP WILL REACH A MAXIMUM BETWEEN 21Z TO 00Z.
AFTER 06Z...CONDITIONS WILL IMPROVE. OBSCURATIONS EXPECTED FOR
MOST MOUNTAINOUS TERRAIN.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...NONE.
UT...NONE.

&&

$$

SHORT TERM...NL
LONG TERM...JAM
AVIATION...TGJT



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