Area Forecast Discussion
Issued by NWS Grand Junction, CO

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000
FXUS65 KGJT 271145
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
545 AM MDT MON OCT 27 2014

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 437 AM MDT MON OCT 27 2014

RAIN AND SNOW SHOWERS REMAIN ONGOING OVER PARTS OF NW COLORADO...BUT
ACTIVITY IS DECREASING AS THE COLD TROUGH CROSSES THE DIVIDE THIS
MORNING. SNOW LEVELS HAVE LOWERED TO BELOW 7000 FEET WITH WEB CAMS
SHOWING SOME SNOW ACCUMULATING AT STEAMBOAT WITH WET ROAD SURFACES.
REMOTE SNOW SENSORS NEAR THE MOUNTAINS ABOVE STEAMBOAT SUGGEST
ABOUT 3-6 INCHES OF NEW SNOW. CHAIN LAWS ARE IN EFFECT FOR RABBIT
EARS PASS...BUT NOT FOR VAIL PASS. RADAR SHOWS PCPN STREAMING OVER
EAGLE COUNTY AND VAIL PASS...BY SUNRISE I70 COULD BE A LITTLE ICY.

MODEL TRENDS INDICATE PCPN WILL BE ENDING FAIRLY QUICKLY THIS
MORNING AS THE TROUGH MOVES DOWNSTREAM. COOLER CONDITIONS WITH
TEMPS SOME 10F TO 15F COOLER THAN SUNDAY AFTERNOON. A FEW LIGHT
BREEZES WILL OCCUR...BUT RELAXING PRESSURE GRADIENT SUGGEST LESS
WIND TODAY.

COOL NORTHWESTERLY FLOW WILL KEEP SEASONALLY NORMAL TEMPERATURES
AND DRY CONDITIONS AROUND THROUGH TUESDAY. THE POTENTIAL FOR A
WIDESPREAD FREEZE IN THE VALLEYS TUESDAY MORNING SUPPORTS THE
ISSUANCE OF A FREEZE WATCH FOR THOSE VALLEYS WHICH HAVEN/T YET
BEEN HIT BY A HARD FREEZE THIS FALL. COOL DAYTIME
TEMPERATURES...CONTINUED COOL AIR ALOFT...CLEAR SKIES...AND LOW
DEWPOINTS ARE EXPECTED TO BRING TEMPERATURES AT THE HIGH VALLEYS
INTO THE UPPER 20S...WITH THE LOWEST VALLEYS ALSO AT RISK FOR A
HARD FREEZE. AS MENTIONED IN PREVIOUS DISCUSSION...MODELS DO HINT
AT A WEAK WAVE PASSING BY ON TUES MORNING...BUT CURRENT THINKING
IS THAT THIS WILL PASS BY WITHOUT ANY NOTICABLE EFFECTS EXCEPT A
COUPLE OKTAS OF HIGH CIRRUS.

.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 437 AM MDT MON OCT 27 2014

TUESDAY NIGHT WILL BE ANOTHER COOL ONE...WITH 00Z MET GUIDANCE AT
GJT SUGGESTING EVEN COOLER TEMPS AROUND SUNRISE. IF THE GRAND
VALLEY DOESN/T REACH A HARD FREEZE TUESDAY MORNING THEN THE CHANCE
IS THERE FOR IT TO OCCUR WEDNESDAY MORNING.

HIGH PRESSURE AMPLIFIES OVER THE WESTERN US ON WEDNESDAY. THE
PRESSURE GRADIENT TIGHTENS SLIGHTLY IN THE AFTERNOON OVER THE
NORTHERN PARTS OF UTAH AND COLORADO SUGGESTING INCREASED WIND
GUSTS DURING THE MIDDAY MIXING PERIOD.

THURSDAY THROUGH SUNDAY...AMPLIFIED RIDGE AXIS CROSSES COLORADO
AND REPLACED BY STRENGTHENING SOUTHWEST FLOW. STRONG MOIST TROUGH
HITS THE WEST COAST WILL BE MOVING ACROSS THE INTERIOR WEST ON
SATURDAY. THE LATEST GFS SHOW TROUGH PASSAGE ON SATURDAY EVENING.
THIS APPEARS TO BE A STRONG TROUGH PASSAGE ALTHOUGH THE MAIN CORE
IS OVER THE ALBERTA PLAINS. SUNDAY WILL BE COOLER IN THE WAKE OF
THE FRONTAL PASSAGE...BUT SOME SHOWERS MAY PERSIST ACROSS THE
NORTH.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 545 AM MDT MON OCT 27 2014

IMPROVING CONDITIONS THIS MORNING AS -SHSN DIMINISH OVER THE NW
COLORADO MOUNTAINS WITH IFR BECOMING VFR THIS AFTERNOON.
WIDESPREAD VFR IS EXPECTED THIS AFTERNOON AND TONIGHT.

SOME MECHANICAL TURBULENCE IS EXPECTED WITH LOCAL SURFACE WIND
G30KTS ACROSS THE FAR SOUTHERN VALLEYS...INCLUDING KDRO.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FREEZE WATCH FROM LATE TONIGHT THROUGH TUESDAY MORNING FOR
     COZ006-011-020.

     WINTER WEATHER ADVISORY UNTIL 9 AM MDT THIS MORNING FOR COZ004-
     010-013.

UT...FREEZE WATCH FROM LATE TONIGHT THROUGH TUESDAY MORNING FOR
     UTZ024.

&&

$$

SHORT TERM...PF/JAM
LONG TERM...JAM/PF
AVIATION...PF



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