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000
FXUS65 KBOU 070303
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
803 PM MST FRI DEC 6 2013

.UPDATE...CLOUDS HAVE SCATTERED OUT THIS EVENING ACROSS NORTHEAST
COLORADO. A DISTURBANCE OVER THE GREAT BASIN IS PRODUCING CLOUDS
OVER UTAH AND NEVADA. THESE CLOUDS WILL MOVE INTO THE STATE
OVERNIGHT AND OVER NORTHEAST COLORADO TOWARDS DAY BREAK. THE MAIN
UPPER LEVEL LOW IS JUST OFF THE OREGON COAST AND WILL AFFECT THE
REGION LATE SATURDAY AND EARLY SUNDAY.

OVERNIGHT LOWS WILL AGAIN BE A CHALLENGE TO FORECAST DUE TO THE
SCATTERED CLOUDS COVER THIS EVENING...THEN THE INCREASING CLOUDS
OVERNIGHT AND WARM AIR ADVECTION. MOST MODELS SHOWING LOWS WILL BE
SET AROUND MIDNIGHT AND TEMPERATURES WILL WARM DURING THE EARLY
MORNING HOURS.THE EXCEPTION BEING OVER THE LOW LYING AREAS OF
NORTHEAST COLORADO WHERE TEMPERATURES WILL SLOWLY FALL THROUGH THE
NIGHT. ADJUSTED FORECAST TOWARDS CURRENT TRENDS...WARMED A FEW
LOCATIONS AND COOL SOME THAT WERE CLOSING IN ON THERE FORECASTED
LOWS.

&&

.AVIATION...SCATTERED LOW CLOUDS THIS EVENING WILL CONTINUE TO
DECREASE THIS EVENING. AS AN UPPER LEVEL DISTURBANCE NEARS THE
STATE...MID LEVEL CLOUDS WILL INCREASE TOWARDS 12Z WITH CEILINGS OF
6000 TO 10000 FEET. LIGHT WINDS WILL PREVAIL WITH NORMAL SOUTHERLY
DIRECTION BY 06Z AT KDEN AND KAPA.

&&

.PREV DISCUSSION... /ISSUED 252 PM MST FRI DEC 6 2013/

SHORT TERM...SOME WARM ADVECTION OVERNIGHT THOUGH COLD AIR WILL
BE STUCK AT LOW LEVELS. IT APPEARS THAT THERE ARE TWO AREAS OF
ENHANCED LIFT...ONE COMING OVER THE MOUNTAINS NOW AND ANOTHER OVER
UTAH. THERE IS MORE MID LEVEL CLOUDINESS AND APPEARS TO BE FAIRLY
WIDESPREAD FLURRIES ASSOCIATED WITH THE FIRST ONE...THE SECOND MAY
BE WEAKER. STILL SOME THIN LOW AND MID LEVEL CLOUDS IN
BETWEEN...BUT LESS. THEN IT LOOKS LIKE A BETTER BREAK BEFORE THE
STRONGER SYSTEM THAT WILL BE ARRIVING SATURDAY EVENING. GIVEN THE
SENSITIVITY OF THE COLD AIR TO VERTICAL MOTION...HARD TO TIME ALL
OF THIS AND TELL THE IMPACTS. BEST CHANCE FOR SNOW AROUND DENVER
IS PROBABLY THROUGH ABOUT 8 PM AND THEN AGAIN EARLY SATURDAY
MORNING. EVEN UNDER THE THICKEST LOOKING CLOUDS OVER THE
MOUNTAINS...VISIBILITIES STILL HAVE LOOKED PRETTY GOOD SO EVEN
THROUGH THERE MAY BE DECENT COVERAGE OF FLURRIES...NOT EXPECTING
MUCH CHANCE OF ACCUMULATING...AT LEAST NOT MORE THAN ONE OR TWO
TENTHS OF AN INCH. CURRENT FORECAST TEMPERATURES LOOKING GOOD WITH
CLOUD COVER HOLDING THINGS UP A BIT TONIGHT...THEN COUNTING ON
SOME SUNSHINE ON SATURDAY OR IT WILL BE A BIT COLDER. LEFT
SATURDAY AFTERNOON POPS ALONE BUT IT MAY BE A BIT TOO FAST TO
BRING IN THE NEXT SYSTEM FOR THE PLAINS.

LONG TERM...MODERATELY STRONG SOUTHWESTERLY FLOW ALOFT IS
PROGGED FOR THE CWA SATURDAY NIGHT INTO SUNDAY MORNING...THEN AN
UPPER TROUGH AXIS MOVES ACROSS SUNDAY MIDDAY AND AFTERNOON. THEN
WEAKER ZONAL FLOW ALOFT IS INDICATED SUNDAY NIGHT INTO MONDAY
MORNING WITH ANOTHER TROUGH AXIS TO MOVE ACROSS MONDAY MIDDAY
INTO THE AFTERNOON. NORTHWESTERLY FLOW ALOFT IS PROGGED MONDAY
NIGHT. THE QG VERTICAL VELOCITY FIELDS SHOW PRETTY STRONG UPWARD
MOTION FOR THE FORECAST AREA SATURDAY NIGHT INTO SUNDAY MORNING.
THERE IS DOWNWARD MOTION PROGGED SUNDAY AFTERNOON AND EVENING
..THEN UPWARD MOTION AGAIN LATE SUNDAY MORNING INTO MONDAY
MORNING. THE REST OF THE MONDAY AND MONDAY NIGHT FEATURES
DOWNWARD MOTION. THE BOUNDARY LAYER WINDS ARE STILL PROGGED TO BE
UPSLOPE FOR THE PLAINS AND FOOTHILLS SATURDAY NIGHT AND SUNDAY. BY
SUNDAY NIGHT...NORMAL DIURNAL PATTERNS ARE PROGGED. ON MONDAY AND
MONDAY NIGHT...THERE IS LOW LEVEL DOWNSLOPING...WITH THE
NORTHWESTERLIES OVER THE EASTERN HALF OF THE PLAINS SOMEWHAT
BRISK. FOR MOISTURE FROM SATURDAY NIGHT INTO SUNDAY EVENING...THE
LATEST MODEL RUNS ARE SHOWING A TAD LESS THAN YESTERDAY`S 12Z RUNS
SHOWED. MORE SO OVER THE PLAINS AS WELL. IT DRIES OUT PRETTY WELL
LATE SUNDAY NIGHT...WITH MONDAY AND MONDAY NIGHT DRY. THERE IS
LIMITED MEASURABLE SNOWFALL NOTED ON THE QPF FIELDS SATURDAY NIGHT
AND SUNDAY FOR MOST OF THE CWA. AMOUNTS ARE MINOR. BY SUNDAY NIGHT
..THERE IS A TAD INDICATED...BUT ONLY OVER THE THE MOUNTAINS.
THERE IS NOTHING ON ANY OF THE MODELS FOR ANY OF THE CWA MONDAY OR
MONDAY NIGHT. SO FOR POPS...WILL LEAVE THEM PRETTY MUCH ALONE
.."LIKELY"S IN THE MOUNTAINS..."CHANCE"S ELSEWHERE...WITH NO
SIGNIFICANT SNOW AMOUNTS AND NO HIGHLIGHTS. WILL DECREASE THINGS A
BIT EARLIER OUT ON THE EASTERN PLAINS SUNDAY AFTERNOON...AND
EVERYWHERE SUNDAY EVENING/OVERNIGHT. MONDAY AFTERNOON AND NIGHT
LOOK DRY FOR ALL AREAS. TEMPERATURE-WISE...SUNDAY`S HIGHS ARE NOW
CLOSE TO SATURDAY`S. THE COLDER AIR ADVERTISED OVER THE PAST
SEVERAL MODEL RUNS HAS GONE AWAY ON THESE LATEST VERSIONS.
MONDAY`S HIGHS WARM UP 0-2 C WARMER THAN SUNDAY`S. FOR THE LATER
DAYS...TUESDAY THROUGH FRIDAY...MODELS HAVE RELATIVELY WEAK
NORTHWESTERLY FLOW ALOFT FOR THE CWA TUESDAY THROUGH THURSDAY. THE
GFS HAS WEAK UPPER RIDGING...THE ECMWF HAS WEAK UPPER TROUGHING
WEDNESDAY AND THURSDAY. BY FRIDAY...THINGS BECOME EVEN MORE
CONVOLUTED. BESIDE ALL THAT...BOTH MODELS SHOW THE CWA PRETTY DRY
ALL FOUR DAYS. TEMPERATURES ARE EXPECTED TO GRADUALLY WARM...AND
MAY GET TO SEASONAL NORMALS ON THURSDAY. ONLY POPS WILL BE ON
TUESDAY NIGHT FOR THE MOUNTAINS...AND THEY WILL BE MINOR.

AVIATION...AN AREA OF LOWER CLOUDS AND FLURRIES WILL PASS OVER
DENVER THROUGH ABOUT 03Z. EXPECT A PERIOD OF MVFR CONDITIONS
DURING THIS TIME. ANY SNOWFALL WILL BE VERY LIGHT. CEILINGS WILL
IMPROVE THIS EVENING...THOUGH THERE COULD STILL BE A LAYER IN THE
5000-8000 FT AGL RANGE REQUIRING INSTRUMENT APPROACHES TO KDEN.
ANOTHER CHANCE OF FLURRIES AND AREAS OF MVFR CONDITIONS BETWEEN
12Z AND 18Z. BETTER CHANCE OF ACCUMULATING SNOW AND LOWER
CONDITIONS SATURDAY NIGHT.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...GIMMESTAD
LONG TERM....RJK
AVIATION...MEIER