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000
FXUS65 KBOU 051934
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
1234 PM MST THU DEC 5 2013

.UPDATE...


&&

.SHORT TERM...SATELLITE SHOWING STRATUS SPREADING NORTH ACROSS
PLAINS...JUST EAST OF DIA. ALSO SOME STRATUS DEVELOPING NEAR THE
FOOTHILLS OF JEFFERSON AND BOULDER COUNTIES. ADDED MORE CLOUDS TO
THE GRIDS IN THESE AREAS FOR THIS AFTERNOON. MAY BE A FEW FLURRIES
FALLING FROM THE CLOUDS. NO OTHER ADDITIONAL UPDATES...YET.

.AVIATION...STRATUS DECK JUST EAST OF KDEN AND KAPA...WITH SOME
STRATUS ALONG FOOTHILLS WEST OF KBJC. CEILINGS AROUND 1500 FEET.
WEAK MESOCYCLONE IN THE DENVER AREA...WHICH WILL BRING THIS
STRATUS WESTWARD. UPDATED KDEN FOR THIS LOWER CLOUD DECK. WILL
ALSO BE UPDATED KBJC AND KAPA AS WELL. COULD BE A FEW FLURRIES
THIS AFTERNOON...STILL THINKING THE BETTER CHANCE WILL BE AFTER
00Z.


&&

.PREV DISCUSSION... /ISSUED 1022 AM MST THU DEC 5 2013/

UPDATE...

SHORT TERM...TEMPERATURES TRYING TO WARM ACROSS THE
AREA...ACTUALLY ABOVE ZERO MOST LOCATIONS. SHOULD WARM A FEW MORE
DEGREES BUT ARCTIC AIRMASS WILL KEEP HIGHS FROM WARMING MUCH ABOVE
10 DEGREES ACROSS THE PLAINS...AND PERHAPS LOWER TO MID TEENS
MOUNTAINS AND FOOTHILLS. LOW LYING AREAS IN THE MOUNTAIN VALLEYS
MAY STRUGGLE TO REACH ZERO DUE TO A FAIRLY STRONG INVERSION.
CLOUDS WILL SPREAD NORTH ACROSS THE AREA BY THE AFTERNOON AS A
WEAK DISTURBANCE MOVES ACROSS SOUTHERN COLORADO. SOME LIGHT SNOW
WILL BE POSSIBLE...CONFINED TO THE MOUNTAINS AND FOOTHILLS. ANY
ACCUMULATIONS WILL BE LIGHT...LESS THAN AN INCH FOR THE HIGH
COUNTRY AND LESS THAN ONE HALF INCH FOR THE PLAINS.
OVERALL...CURRENT FORECASTS SEEM OKAY BUT DELAYED THE TIMING OF
ANY SNOW TO THE AFTERNOON. HIGH TEMPERATURES IN THE MOUNTAIN
VALLEYS NEED A BIT OF LOWERING.

AVIATION...OVERALL...CURRENT TAF TRENDS LOOK REASONABLE. WINDS
TURNING MORE CLOCKWISE THAN COUNTERCLOCKWISE...CURRENTLY LIGHT
NORTHWEST...WILL CHANGE THE DIRECTION TO ADJUST FOR THIS TREND.
STILL SOME CHANCE OF LIGHT SNOW THIS AFTERNOON AND EVENING...WITH
LOWERING CEILINGS. ENOUGH MOISTURE AND A BIT OF LIFT COULD SQUEEZE
OUT SOME LIGHT SNOW. WILL KEEP THE TEMPO GROUPS GOING. STRATUS
SHOULD PERSIST INTO THE MORNING HOURS FRIDAY...WITH SOME
IMPROVEMENT BY 18Z. NOT SURE IF ANY FOG WILL DEVELOP...BUT WILL
MONITOR.

PREV DISCUSSION... /ISSUED 351 AM MST THU DEC 5 2013/

SHORT TERM...VERY FRIGID TEMPERATURES THIS MORNING AS SKIES
CLEARED OVERNIGHT. A COUPLE OF PLACES HAVE BROKEN MINIMUM
TEMPERATURES RECORDS INCLUDING DENVER...WHERE -13 DEGREES BEFORE
MIDNIGHT SMASHED YESTERDAYS MINIMUM TEMPERATURE RECORD OF -5
DEGREES.

WITH SUCH COLD TEMPERATURES TO START OUT THE DAY ALONG WITH A WEAK
DISTURBANCE PASSING OVERHEAD BRINGING SLIGHTLY COOLER TEMPERATURES
ALOFT...HIGH TEMPERATURES WILL BE SIMILAR IF NOT COOLER TO
YESTERDAY`S HIGHS. SINGLE DIGITS ARE EXPECTED FOR THE PLAINS AND
SINGLE DIGITS TO READINGS BELOW ZERO FOR THE MOUNTAINS. THIS
DISTURBANCE WILL ALSO BRING AREAS OF LIGHT SNOW TO THE MOUNTAINS
AND FOOTHILLS AND A SLIGHT CHANCE TO THE METRO AREAS...MAINLY IN
THE AFTERNOON AND EVENING. MOST OF THE ENERGY OF THIS DISTURBANCE
WILL BE TO THE SOUTH OF THE AREA...SO ACCUMULATIONS WILL BE LIGHT.
LESS THAN AN INCH IN THE HIGH COUNTRY AND LESS THAN HALF AN INCH
OVER THE PLAINS.

CLOUD COVER FROM THE DISTURBANCE WILL LIKELY LAST THROUGH THE
NIGHT TO KEEP MINIMUM TEMPERATURES FROM REACHING THE COLD READINGS
WE SAW EARLY THIS MORNING.

LONG TERM...COLD...COLD...COLD. TEMPERATURES STILL LOOK LIKE THEY
WILL REMAIN BELOW FREEZING THROUGH MONDAY...AND POSSIBLY INTO
TUESDAY. NORTHERLY FLOW ALOFT WILL CONTINUE OVER THE WESTERN U.S.
AND COLORADO AS A BLOCKING RIDGE REMAINS OVER THE GULF OF ALASKA.
FRIDAY AND SATURDAY WILL BE PLAIN COLD WITHOUT VERY MUCH
PRECIPITATION AS THE AIRMASS OVER THE STATE REMAINS DRY. FROM LATE
SATURDAY THROUGH SUNDAY...ALL MODELS CONTINUE INDICATING A
REINFORCING SHOT OF COLD AIR ALONG WITH AN UPPER TROUGH THAT RIDES
DOWN THE BACKSIDE OF THE BLOCKING RIDGE AND ROTATES OVER THE GREAT
BASIN. QUASI-GEOSTROPHIC DIAGNOSTICS SHOWS THAT THE TROUGH WILL
CONTAIN QUITE A BIT OF DYNAMIC FORCING OVER COLORADO ON SUNDAY. IT
DOES NOT LOOK LIKE THERE WILL BE AN INORDINATE AMOUNT OF MOISTURE
WITH THE TROUGH...BUT WILL CERTAINLY BE ENOUGH TO PRODUCE SNOWFALL
FOR A 12-24 HOUR PERIOD. IT IS POSSIBLE THAT SOME GULF MOISTURE
WILL ENTRAIN INTO THE TROUGH AS IT APPROACHES...WHICH WOULD
ENHANCE SNOWFALL AMOUNTS. FOR THE TIME BEING WILL JUST STICK WITH
A CHANCE OF SNOW ACROSS THE PLAINS SUNDAY...AND SNOW LIKELY IN
THE MOUNTAINS. AFTER THIS UPPER TROUGH MOVES THROUGH THE UPPER AIR
PATTERN IS EXPECTED TO BEGIN CHANGING AS THE BLOCKING PACIFIC
RIDGE BREAKS DOWN. WITH INCREASING WESTERLY FLOW ALOFT...THE COLD
AIR WILL GRADUALLY BE REPLACED BY WARMER AIR. THIS TRANSITION WILL
OCCUR ON EITHER TUESDAY OR WEDNESDAY...WITH THE GFS SOLUTION SOME
24 HOURS FASTER THAN THE ECMWF. THE CURRENT FORECAST LEANS TOWARD
THE ECMWF SOLUTION WITH SOME WARMING ON TUESDAY AND MORE WARMING
ON WEDNESDAY. A PERIOD OF GUSTY...CHINOOK WINDS MAY ACCOMPANY THE
WARM-UP...AND WILL PROBABLY BE THE DRIVING MECHANISM THAT BRINGS
AN END TO THE COLD SPELL.

AVIATION...SHALLOW FOG IS POSSIBLE IN LOW LYING AREAS WITH THE
CLEAR SKIES...BUT LOOKING AT DEW POINT DEPRESSIONS...DON`T THINK
IT WILL AFFECT THE AIRPORTS. CAN`T TOTALLY RULE IT OUT YET
HOWEVER. MID CLOUDS WILL INCREASE THIS AFTERNOON WITH CEILINGS OF
3000 TO 6000 FEET POSSIBLE AS WELL AS VERY LIGHT SNOW THROUGH THE
EVENING. SOUTHEASTERLY WINDS WILL CONTINUE THROUGH THE MORNING
TRANSITIONING TO EAST-NORTHEASTERLY THIS AFTERNOON BEFORE
RETURNING TO SOUTHEAST.

&&

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

$$

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