Area Forecast Discussion
Issued by NWS Grand Junction, CO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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 260429
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
929 PM MST THU DEC 25 2014

.UPDATE...
ISSUED AT 925 PM MST THU DEC 25 2014

CALLS TO DURANGO AND PAGOSA SPRINGS DISPATCH REVEAL 2-4 INCH
ACCUMULATIONS WITH TRAFFIC ACCIDENTS IN ARCHULETA COUNTY. THE 00Z
NAM IS PAINTING 4-12 ADDITIONAL INCHES IN ARCHULETA AND EASTERN LA
PLATA COUNTY THROUGH FRIDAY EVENING. THIS FITS IN GOOD COLD
ADVECTIVE CYCLONIC FLOW WITH A CONVERGENT-DIVERGENT COUPLET. SO
HAVE RAISED THOSE ZONES TO WARNINGS. THANKS TO ABQ FOR
COORDINATION.

ELSEWHERE A GENERAL DOWNTURN IS EXPECTED TONIGHT WITH ENHANCEMENT
FRIDAY AFTERNOON AS INSTABILITY INCREASES SOMEWHAT. THE GRAND
VALLEY WILL STRUGGLE TO GET MUCH MORE ACCUMULATION.

DIFFICULT TRAVEL CONDITIONS EXIST ACROSS THE ENTIRE CWA EXCEPT IN
THE VALLEYS OF SE UTAH.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 359 PM MST THU DEC 25 2014

INTERESTING STORM TODAY...A BIT SLOWER THAN ANTICIPATED AND TURNED
QUITE CONVECTIVE DURING THE LATE MORNING. THE GRAND MESA IS THE
WINNER SO FAR WITH OVER A FOOT OF NEW SNOW ON TOP. WITH THE SLOW-
DOWN OF THE LOW PRESSURE SYSTEM...DECIDED TO UPGRADE ADVISORIES TO
WARNINGS FOR THE GRAND MESA...CENTRAL MTNS...AND NORTHERN MTNS.
LEFT THE SAN JUANS IN AN ADVISORY ANTICIPATING LESS WRAP AROUND
FLOW ON FRIDAY. THE COLD FRONT ASSOCIATED WITH THIS SYSTEM IS
CURRENTLY JUST EAST OF THE WASATCH RANGE. WITH COOLER AIR MOVING
IN FROM THE WEST ALOFT...CONVECTIVE BANDS HAVE DEVELOPED AND ARE
MOVING FROM SOUTHWEST TO NORTHEAST AHEAD OF THE FRONT. THIS ALIGNS
WELL WITH INSTABILITY SHOWN IN THE H5 TO H3 POTENTIAL VORTICITY
FIELDS. THE CENTER OF THE LOW PRESSURE SYSTEM IS STILL EXPECTED
TO SAG SOUTH TO SW COLORADO BY NOON FRIDAY...WHICH WILL HELP TO
KEEP INTERMITTENT SNOWFALL ACROSS THE FORECAST AREA. AS THE LOW
DROPS SOUTH...PREVAILING WIND DIRECTIONS AT THE TIME WILL CHANGE
AND THEREFORE THE SNOWFALL AMOUNTS WILL BE RATHER DYNAMIC DUE TO
TOPOGRAPHIC INFLUENCES. WRAP AROUND MOISTURE WILL BE MOST
PREVALENT OVER THE CENTRAL MOUNTAINS AND POTENTIALLY THE
SOUTHCENTRAL SAN JUANS AS WELL.

THE CLOSED LOW IS EXPECTED TO FALL APART AS IT REACHES THE
CONTINENTAL DIVIDE AND ITS ASSOCIATED TROUGH WILL SLOWLY EXIT TO
THE NORTHEAST ON FRIDAY NIGHT.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 359 PM MST THU DEC 25 2014

OTHER THAN A FEW LINGERING SHOWERS IN NORTHWEST FLOW OVER THE
NORTHCENTRAL COLORADO MOUNTAINS...ELSEWHERE IS EXPECTED TO BE COLD
AND DRY BY SATURDAY MORNING. ZONAL FLOW DEVELOPS DURING SATURDAY
EVENING BEFORE THE NEXT SYSTEM APPROACHES THE FORECAST AREA.
PRECIPITATION IS PROGGED TO BEGIN SUNDAY MORNING OVER NE UTAH AND
NW COLORADO THEN GRADUALLY DROP DOWN TO AFFECT THE NORTHERN HALF
OF BOTH STATES. THIS SYSTEM LOOKS TO BE UNIQUE IN THAT IT IS A
BROAD AND WIDE TROUGH WITH A MULTIPART LONG LIVED WEATHER SYSTEM.
THERE HASN/T BEEN GREAT RUN TO RUN CONSISTENCY ON WHERE A CLOSED
LOW MAY DEVELOP MIDWEEK...BUT THE GENERAL CONSENSUS HAS BEEN A
CHANCE OF SNOW OVER NE UTAH AND NW COLORADO ON SUNDAY INTO
MONDAY...THEN THE PRECIPITATION THREAT MOVES SOUTH MONDAY NIGHT
INTO TUESDAY WHILE A CLOSED LOW DEVELOPS SOMEWHERE FROM SOCAL TO
SOUTHERN NV. THIS MIGHT AFFECT SOUTHERN UT BY THURSDAY...BUT
CONFIDENCE IS LOW SO WILL HAVE TO WAIT AND SEE WHAT FUTURE MODEL
RUNS HOLD.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY EVENING)
ISSUED AT 925 PM MST THU DEC 25 2014

SNOWFALL WILL CONTINUE THROUGH FRIDAY AFTERNOON FOR THE COLORADO
TAF SITES. EXPECT CIGS BLO 020 AND VIS BLO 3SM IN -SHSN. MTN TOPS
WILL BE OBSCURED. THE EXCEPTION IS KGJT AND EASTERN UTAH AIRPORTS
THAT WILL SEE SCT SNOW SHOWERS WITH MVFR ISOLD IFR CONDITIONS.
LOCALIZED HEAVY CONVECTIVE SHOWERS ARE EXPECTED 18Z-24Z FRIDAY
MAINLY IN THE COLORADO MTNS AND ADJOINING VALLEYS INCLUDING KHDN
KSBS KEGE KASE KTEX KDRO KPSO.


&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 6 PM MST FRIDAY FOR COZ001-002-007-
     011.

     WINTER WEATHER ADVISORY UNTIL 3 PM MST FRIDAY FOR COZ006-020.

     WINTER STORM WARNING UNTIL MIDNIGHT MST FRIDAY NIGHT FOR COZ004-
     009-010-012-013-019-022-023.

     WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST FRIDAY NIGHT FOR
     COZ003-005-008-014-017-018.

UT...WINTER WEATHER ADVISORY UNTIL 6 PM MST FRIDAY FOR UTZ023-025-028.

     WINTER WEATHER ADVISORY UNTIL 3 PM MST FRIDAY FOR UTZ024-027-029.

&&

$$

UPDATE...JOE
SHORT TERM...JAM
LONG TERM...JAM
AVIATION...JOE



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