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000
FXUS65 KBOU 041905
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
1205 PM MST WED DEC 4 2013

.UPDATE...


&&

.SHORT TERM...SNOW CONTINUES TO DECREASE ACROSS THE URBAN
CORRIDOR...STILL SOME MODERATE SNOW ACROSS THE PALMER DIVIDE. ALSO
SOME SNOW ONGOING ACROSS THE MOUNTAINS...FOOTHILLS AND MOUNTAIN
VALLEYS. MODELS STILL SHOWING THE SNOW DECREASING THROUGH THE
AFTERNOON AS THE LIFT HEADS SOUTH OF THE CFWA AND
SUBSIDENCE...DRYING PUSHES IN FROM THE NORTH. BASED ON CURRENT
AND EXPECTED TRENDS...WILL DROP HILITES FOR THE URBAN CORRIDOR AND
ADJACENT PLAINS...AND DOWNGRADING WARNING TO ADVISORY FOR THE
PALMER DIVIDE. FOR MOUNTAIN VALLEYS AND FOOTHILLS...WILL DOWNGRADE
THE WARNING TO AN ADVISORY. STILL THINKING ANOTHER 1 TO 4 INCHES...
MAINLY SOUTHERN FOOTHILLS AND PARK COUNTY. MAIN IMPACT TO BE THE
SNOWPACKED ROADS. WILL KEEP MOUNTAIN WARNINGS GO FOR NOW...WITH
WITH POSSIBLE 2 TO 4 INCHES MAINLY WEST FACING SLOPES. AGAIN MAIN
IMPACT TO BE THE SNOWPACKED ROADS. STILL SOME LIGHT SNOW POSSIBLE
FOR THE PLAINS...BUT WILL DECREASE POPS.

.AVIATION...CONDITIONS CONTINUE TO IMPROVE AT KBJC AND
KDEN...WILL UPDATE FOR THE IMPROVEMENT. STILL SOME MODERATE SNOW
MOVING TOWARD KAPA AND WILL MAINTAIN THE CURRENT TAF THERE FOR
NOW. STILL MVFR CONDITIONS PREVAILING WITH OCCASIONAL IFR AT KAPA.

&&

.PREV DISCUSSION... /ISSUED 1017 AM MST WED DEC 4 2013/

UPDATE...

SHORT TERM...BAND OF MODERATE TO OCCASIONAL HEAVY SNOW HAS MOVED
EAST OF THE URBAN CORRIDOR...APPEARS TO HAVE SLOWED ITS EASTWARD
PROGRESS AND SEEMS TO HEADING MORE SOUTHEAST. MAIN AREA OF THE
HEAVIER SNOW NOW FROM SOUTHERN JEFFERSON COUNTY ACROSS DOUGLAS AND
NORTHERN ELBERT COUNTIES THEN ACROSS FAR EASTERN ADAMS AND EASTERN
ARAPAHOE COUNTIES. LIGHT SNOW OCCURRING ACROSS REST OF THE AREA
WITH SOME EMBEDDED MODERATE SNOW. LOOKING LIKE THIS ONGOING SNOW
SHOULD BE GRADUALLY DECREASING AND HEADING SOUTHEAST AS MAIN
DYNAMICS WITH UPPER JET SAGS SOUTH ACROSS COLORADO. WEB CAMS AND
SURFACE OBS SHOW THAT SNOW HAS DECREASED CONSIDERABLY FROM BOULDER
NORTHWARD TO THE WYOMING BORDER...INCLUDING THE NORTHERN
FOOTHILLS. LATEST MODELS NOT SHOWING MUCH ADDITIONAL ACCUMULATION
FOR THROUGH THE AFTERNOON. FOR THIS UPDATE...PLANNING ON CANNING
THE HILITES FOR ZONES 35 AND 38. LEAVE REST OF HILITES ALONE FOR
NOW...STILL DECENT SNOW FALL ON RADAR ACROSS PARTS OF ZONES 39 AND
40 AS WELL AS ZONE 36 AND PORTIONS OF 37. SNOWING LIGHTLY ACROSS
MOUNTAINS AND MOUNTAIN VALLEYS AND THESE AREAS COULD SEE ANOTHER 1
TO 3 INCHES BY EVENING AND MAY END UP DOWNPLAYING OR CANCELLING
THE WARNING THERE. WILL MAKE THE FINAL DECISIONS SHORTLY. REST OF
FORECASTS SEEM OKAY FOR NOW.

AVIATION...LIGHT SNOW SNOW OCCURRING ACROSS THE AREA AIRPORTS
THOUGH VISIBILITIES HAVE BEEN SLOWLY IMPROVING. STILL SOME AREAS
OF MODERATE ACROSS WESTERN DENVER AREA...COULD STILL AFFECT LOCAL
AIRPORTS THROUGH ABOUT 20Z. WILL CONTINUE TRENDS OF CURRENT
TAFS...WITH GRADUAL IMPROVEMENT THROUGH THE AFTERNOON. EXPECT SNOW
TO END BY 02Z WITH VFR CONDITIONS. ANY ADDITIONAL ACCUMULATIONS
TO BE LESS THAN AN INCH...WITH PERHAPS AN INCH IF THE MODERATE
SNOW AFFECTS THE AREA AIRPORTS.

PREV DISCUSSION... /ISSUED 328 AM MST WED DEC 4 2013/

SHORT TERM...SNOW HAS GENERALLY BEEN ON THE LIGHT SIDE OVER THE
CWA TONIGHT WITH AMOUNTS SO FAR LOWER THAN EXPECTED. APPEARS THE
MOISTURE DEPTH IS RATHER SHALLOW AND UPSLOPE FLOW ONLY UP TO
AROUND 9000FT MSL. STARTING TO SEE SOME ENHANCEMENT ON THE RADAR
OVER JEFFERSON AND DOUGLAS COUNTIES AND FURTHER NORTH OVER
LARIMER COUNTIES. STILL EXPECT THE BEST POTENTIAL FOR THE HEAVIER
SNOW BETWEEN 4 AM AND 11 AM THIS MORNING AS THE STRONG UPPER LEVEL
JET SLOWLY SAGS SOUTHWARD OVER OUR AREA. WILL LEAVE ALL HILITES AS
IS SINCE THE BEST POTENTIAL IS STILL TO COME. MAIN CHANGE TO
FORECAST WILL BE TO LOWER THE OVERALL SNOW AMOUNTS. AS THE JET
SAGS SOUTHWARD THIS AFTERNOON AND GRADUALLY SUBSIDENT AIR BEGINS
TO MOVE IN LATER IN THE DAY. FORECAST TRENDS SHOW DECREASING SNOW
LATE IN THE DAY AND DIMINISHING FROM NORTH TO SOUTH DURING THE
LATE AFTERNOON AND EVENING. EXPECT SOME CURRENT WARNING HILITES
WILL BE DROPPED SOONER THAN 6 PM ESPECIALLY OVER THE NORTHERN
ZONES.

TEMPERATURES WILL STAY FAIRLY STEADY TODAY IN THE SINGLE DIGITS TO
LOWER TEENS...WITH THE COLDEST READINGS NEAR THE WYOMING BORDER.
WITH SOME CLEARING EXPECTED TONIGHT TEMPERATURES COULD DROP TO 10
DEGREES BELOW ZERO OR MORE.

LONG TERM...A LARGE AND NEARLY STATIONARY LONGWAVE UPPER TROUGH
STRETCHING FROM CENTRAL CANADA THEN INTO THE SOUTHWESTERN STATES
THROUGH THE PERIOD WILL KEEP THE COLD WEATHER PATTERN OVER
NORTHEASTERN COLORADO. A WEAK DISTURBANCE THURSDAY WILL BRING A
SLIGHT CHANCE OF SNOW TO THE MOUNTAINS...FOOTHILLS AND MAINLY THE
SOUTHERN SECTIONS OF THE METRO AREAS INCLUDING THE PALMER DIVIDE.
ACCUMULATIONS WILL BE LESS THAN 2 INCHES IN THE HIGH COUNTRY AND
LESS THAN HALF AN INCH OVER THE PLAINS. HIGH AND LOW TEMPERATURES
THIS DAY AND NIGHT WILL LIKELY BE THE LOWEST OF THIS PERIOD AS
MORE COLD AIR IS PUSHED INTO THE STATE.

SLIGHT RIDGING WILL BRING A LITTLE WARMER TEMPERATURES AND DRIER
WEATHER FRIDAY BEFORE ANOTHER SHORTWAVE TROUGH SWINGS THROUGH FOR
SATURDAY AND INTO SUNDAY. MODELS SHOWING BETTER CONSISTENCY FOR
THIS SYSTEM WITH SNOW SPREADING INTO THE MOUNTAINS LATE FRIDAY
NIGHT AND SATURDAY THEN SPREADING OVER THE PLAINS SATURDAY NIGHT
AND INTO SUNDAY. MOISTURE IS COMING FROM MAINLY CONTINENTAL CANADA
FOR THIS SYSTEM...SO AMOUNTS AREN`T GOING TO BE SUBSTANTIAL.
PERHAPS JUST A FEW INCHES OR MORE IN THE MOUNTAINS THEN A COUPLE
OVER THE PLAINS. COLD TEMPERATURES WILL CONTINUE AS MORE COLD AIR
IS PUSHED SOUTH INTO THE STATE.

THE STRONG COLD SNAP LOOKS TO BE COMING TO AN END NEXT WEEK AS
THE LONGWAVE TROUGH FINALLY PUSHES EAST TO ALLOW RIDGING TO BUILD
IN. YET...STILL EXPECTING TEMPERATURES TO REMAIN BELOW FREEZING
THROUGH MONDAY AND MOST LIKELY TUESDAY AS WELL. THERE ARE SOME
INDICATIONS THAT ANOTHER TROUGH WILL PUSH THROUGH MID WEEK TO
BRING COLDER TEMPERATURES...BUT OVERALL ITS BECOMING MORE OF A
ZONAL PATTERN WHICH WILL MODERATE TEMPERATURES.

AVIATION...LIGHT SNOW WILL CONTINUE AT LOCAL TERMINALS BUT SHOULD
SEE AN INCREASE IN SNOW INTENSITY AND LOWER CEILINGS BETWEEN 4 AM
AND 11 AM WITH THE BEST POTENTIAL FOR HEAVIER SNOW. SNOW
ACCUMULATIONS TODAY AT THE AIRPORTS WILL RANGE FROM 3 TO 5
INCHES...WITH UP TO 8 INCHES POSSIBLE AT BJC. SURFACE WINDS WILL
REMAIN FROM THE NORTH AND NORTHEAST AT 10 TO 15 MPH. SNOW WILL
DIMINISH LATE AFTERNOON/EVENING AND PARTIAL CLEARING BY LATE
EVENING.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM MST THIS EVENING FOR COZ030-
032-035>037-041.

WINTER STORM WARNING UNTIL 6 PM MST THIS EVENING FOR COZ031-033-
034.

&&

$$

SHORT TERM...D-L
LONG TERM....KRIEDERMAN
AVIATION...D-L