National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS65 KGJT 091102
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
402 AM MST MON DEC 9 2013

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 402 AM MST MON DEC 9 2013

COLD AIR WILL REMAIN TRAPPED IN THE VALLEYS FOR THE FORESEEABLE
FUTURE. STRONG INVERSIONS THREATEN STRATUS AND FOG AND
EVENTUALLY... DECREASING AIR QUALITY.

AN OPEN WAVE WAS PASSING EAST OF THE CONTINENTAL DIVIDE THIS EARLY
MORNING. SNOTEL SITES WERE NOT IMPRESSED WITH ITS PASSING...WITH
THE NORTHERN SITES ONLY SHOWING A FEW TENTHS OF AN INCH OF SNOW
WATER EQUIVALENT ACCUMULATION OVERNIGHT. SOME SNOW WAS RECORDED IN
THE NORTHERN VALLEYS WITH GENERALLY DRY OBSERVATIONS SOUTH OF
I-70. THE MID-HIGH CLOUDS WITH THE WAVE HELPED TO MODIFY MIN TEMPS
ACROSS THE NORTH-CENTRAL ZONES THROUGH MUCH OF THE NIGHT KEEPING
VALLEY LOWS NEAR ZERO. THIS IN CONTRAST TO MORNING LOWS AT
GUNNISON...DURANGO...AND PAGOSA NEAR -15F. FREEZING FOG REMAINS A
THREAT THIS MORNING IN THE VALLEY BOTTOMS.

OTHERWISE...STRONG WARMING IN THE 550-650MB LAYER BEGINS THIS
AFTERNOON. THE TOP OF THIS POWERFUL INVERSION WILL RANGE FROM
13KFT NORTH TO NEAR 10KFT SOUTH. FOR THE NORTHERN COLORADO MTNS THE
MODELS HINT AT SATURATION IN THE MID-UPPER PORTION OF THE
INVERSION. THIS POSSIBLY WILL PRODUCE PERSISTENT LOW STRATUS IN
THE STEAMBOAT AREA WITH FOG ON THE SLOPES PARK/GORE RANGES NORTH
OF VAIL PASS. LIGHT SNOW COULD FALL OUT OF THIS STRATUS. ELSEWHERE
MODELS SHOW LESS MOISTURE IN THE INVERSION WITH VALLEY SURFACE
TEMPERATURES FALLING TO THE DEWPOINT FOR AREAS OF FREEZING FOG
TONIGHT INTO TUESDAY. AS SEEN WITH THE LAST WIDESPREAD SNOW
STORM...THESE AREAS OF STRATUS AND FOG CAN BECOME WIDESPREAD AND
LONG LIVED.

THE NEXT WEAK WAVE PASSES OVER THE NORTH TUESDAY. THIS MAY CREATE
SOME OVERRUNNING SNOWFALL MAINLY FOR THE ELKHEADS/ZIRKELS/PARK
/FLATTOPS MTN RANGES. LITTLE EFFECT IS EXPECTED FROM THIS PASSING
WAVE ELSEWHERE. TUESDAY AFTERNOON SLOPE TEMPERATURES MAY BE
MILDER THAN THE VALLEY BOTTOMS.

.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 402 AM MST MON DEC 9 2013

MODELS WERE IN VERY GOOD AGREEMENT THROUGH THURSDAY WITH MINOR
DIFFERENCES APPARENT DURING THE LATTER PART OF THE WEEK AND INTO
THE WEEKEND.

WITH THE LONGWAVE TROUGH OVER THE PLAINS...THE FORECAST AREA WILL
BE UNDER A RELATIVELY DRY NORTHWEST FLOW THROUGH MIDWEEK. HOWEVER
...MODELS DID INDICATE A WEAK SHORTWAVE CLIPPING THE NORTHERN
MOUNTAINS COULD BRING SOME LIGHT SNOWFALL TUESDAY NIGHT.

A CLOSED LOW OVER SOUTHERN CALIFORNIA MOVES INLAND THURSDAY...
SWEEPING ACROSS THE DESERT SOUTHWEST THURSDAY NIGHT THEN PUSHING
TO THE SOUTHERN PLAINS FRIDAY MORNING. BOTH ECMWF AND GFS
INDICATED MOISTURE ASSOCIATED WITH THIS SYSTEM WILL STAY SOUTH OF
THE FORECAST AREA FOR CONTINUED DRY WEATHER.

ECMWF AND GFS DIFFERED WITH SHORTWAVE DROPPING DOWN FROM THE
PACIFIC NORTHWEST FRIDAY. 00Z/MON GFS A BIT SHALLOWER...FASTER
MOVING...AND DRIER THAN THE ECMWF SOLUTION. IN CONTRAST...THE
ECMWF BRINGS A CHANCE FOR SNOWFALL TO THE NORTHERN MOUNTAINS FROM
FRIDAY NIGHT THROUGH SATURDAY MORNING. HOWEVER...NOT MUCH SNOW
INDICATED.

UNEVENTFUL NORTHWEST FLOW FOLLOWS THIS WEEKEND.

TEMPERATURES SHOULD MODERATE DURING THE LATTER PART OF THE WEEK
AND INTO THE WEEKEND. HOWEVER...VALLEYS WILL BE SLOWER TO WARM DUE
TO STRONG INVERSIONS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 402 AM MST MON DEC 9 2013

THE TRAILING EDGE OF THIS WEEKEND/S STORM WILL BRING SCATTERED
LIGHT SNOW SHOWERS TO THE NORTHERN AND CENTRAL MOUNTAINS THROUGH
18Z RESULTING IN AREAS OF MOUNTAIN OBSCURATION. ELSEWHERE...EXCEPT
FOR AREAS OF MVFR CIGS EAST AND SOUTHEAST OF KCAG AND THE VAIL
VALLEY THIS MORNING...VFR CONDITIONS WILL BE THE RULE ACROSS THE
FORECAST AREA THROUGH THE NEXT 24 HOURS.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...WINTER WEATHER ADVISORY UNTIL 6 AM MST EARLY THIS MORNING FOR
     COZ004-010-013.

UT...NONE.

&&

$$

SHORT TERM...JOE
LONG TERM...NL
AVIATION...NL