National Weather Service Weather Forecast Office

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

000
FXUS65 KBOU 010419
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
919 PM MST SAT NOV 30 2013

.UPDATE...

&&

.SHORT TERM...MINOR ADJUSTMENTS AS COOLING IS A BIT AHEAD OF
SCHEDULE IN THE COLD SPOTS. CLOUDS STARTING TO DEVELOP...MAINLY
OVER THE FRONT RANGE IN THE MOUNTAIN WAVE...BUT SLOWED THEIR
DEVELOPMENT A FEW HOURS.

&&

.AVIATION...VFR THROUGH SUNDAY. SOUTH/WEST DRAINAGE WINDS
TONIGHT...THEN WEST WINDS MIXING INTO KDEN/KAPA IN THE MORNING AND
CONTINUING THROUGH THE DAY. GUSTS TO 25 KNOTS POSSIBLE...A LITTLE
STRONGER AT KBJC.

&&

.PREV DISCUSSION... /ISSUED 312 PM MST SAT NOV 30 2013/

SHORT TERM...MILD AND FAIRLY TRANQUIL WEATHER WILL REMAIN IN
PLACE THROUGH TONIGHT...WITH ONLY A GRADUAL INCREASE IN MID/HIGH
CLOUD COVER. BY EARLY SUNDAY MORNING...NOSE OF UPPER LEVEL JET
WILL APPROACH NORTHERN COLORADO. MOISTURE WILL CONTINUE TO
GRADUALLY INCREASE AND OROGRAPHICS WILL STRENGTHEN.
HOWEVER...MOISTURE IS STILL QUITE SHALLOW THROUGH SUNDAY AND
AIRMASS IS STABLE WITH VERY POOR LAPSE RATES IN THE MOIST LAYER.
AS A RESULT...ANY SNOWFALL IS EXPECTED TO BE LIGHT...PERHAPS A
COUPLE INCHES IN THE MOUNTAINS FROM NEAR RABBIT EARS PASS INTO THE
MOUNT ZIRKEL WILDERNESS AREA...WITH EVEN LIGHTER AMOUNTS IF ANY
ACCUMULATION AT ALL OVER MOST OF SUMMIT COUNTY WHERE MOISTURE IS
EVEN MORE LIMITED.

MOUNTAIN WAVE EXPECTED TO REMAIN IN PLACE TONIGHT WITH MOUNTAIN
TOP STABLE LAYER IN PLACE...ALTHOUGH CROSS MOUNTAIN FLOW IS ONLY
25-30 KTS OVERNIGHT. HOWEVER...ON SUNDAY THE CROSS MOUNTAIN FLOW
INCREASES TO NEARLY 40 KTS BY AFTERNOON. WITH WEAK COLD ADVECTION
ALOFT...THIS SHOULD ALLOW THE ATMOSPHERE TO MIX SUFFICIENTLY. AS A
RESULT...THE GUSTY WINDS IN/NEAR THE FRONT RANGE WILL GRADUALLY
SPREAD EAST ACROSS THE PLAINS BY AFTERNOON. AS THE FLOW
STRENGTHENS...PEAK GUSTS SHOULD REACH 40-50 MPH IN WIND PRONE
AREAS OF THE FOOTHILLS AND MOUNTAINS...WITH 30-40 MPH GUSTS ON THE
ADJACENT PLAINS. TEMPERATURES WILL REMAIN QUITE MILD ON THE PLAINS
WITH ONLY WEAK COLD ADVECTION.

LONG TERM...BIG CHANGES ARE COMING DOWN THE PIKE. FIRST
OFF...SUNDAY NIGHT AND MONDAY LOOK LIKE A PRETTY HEALTHY EPISODE
OF WIND IN THE MOUNTAINS AND FOOTHILLS. STRONG NORTHWEST FLOW
ALOFT IS GOING TO BE SITUATED OVER THE STATE. THE AIRMASS WILL BE
MOISTENING OVER TIME SUNDAY NIGHT AND MONDAY WHICH WILL EVENTUALLY
LEAD TO SOME OROGRAPHIC SNOW IN THE MOUNTAINS. WIND OVER THE
RIDGES AND DOWN THE EAST SLOPES COULD INCREASE TO THE 50-70 MPH
RANGE. THE WIND WILL CONTINUE THROUGH MONDAY AND MAY SPREAD ONTO
THE PLAINS AT TIMES DUE TO MIXING WITH DAYTIME HEATING.

IT NOW APPEARS THAT THE MAIN COLD FRONT WILL BE MOVING INTO THE
STATE LATE TUESDAY AFTERNOON OR TUESDAY NIGHT. THE GFS APPEARS TO
BE TOO FAST...COMPARED TO THE OTHER MODELS. WITH THE ARRIVAL OF
THE COLD AIR...THE REST OF THE WEEK WILL BE MUCH COLDER THAN
NORMAL AS NORTHERLY FLOW ALOFT IS EXPECTED TO CONTINUE. ONE SURGE
OF COLD AIR MOVING INTO THE REGION WEDNESDAY NIGHT WILL HELP KEEP
TEMPERATURES THURSDAY IN THE LOWER TEENS. OVERNIGHT LOWS MAY WELL
DROP BELOW ZERO ACROSS THE PLAINS. AFTER THE INITIAL FRONT TUESDAY
NIGHT...THE AIRMASS WILL MOISTEN UP AND LOW LEVEL FLOW WILL TURN
TO NORTHEASTERLY...LEADING TO PERIODS OF LIGHT SNOW THROUGH
WEDNESDAY AND THURSDAY. SOME MODERATION OF TEMPERATURES WILL BE
POSSIBLE FRIDAY AND SATURDAY...BUT THE ECMWF AND GFS ARE SHOWING
ANOTHER SURGE OF COLD AIR MOVING OUT OF BRITISH COLUMBIA ON
SATURDAY WHICH WILL MOVE INTO COLORADO SUNDAY OR MONDAY. THE MAIN
STORY IS THAT THIS WILL BE THE STRONGEST ARCTIC OUTBREAK THAT WE
HAVE SEEN IN ALMOST THREE YEARS.

AVIATION...NORMAL AND LIGHT DIURNAL WIND PATTERNS SHOULD PREVAIL
THROUGH TONIGHT...ALTHOUGH SOME GUSTS TO 25-30 KTS EXPECTED TO
DEVELOP AT KBJC AFTER 09Z. ON SUNDAY...THE GUSTY WINDS AT KBJC
WILL LIKELY SPREAD EAST TO KDEN AND KAPA BY 19Z-21Z AS AIRMASS
WARMS AND MIXES SUFFICIENTLY. VFR CONDITIONS WILL PERSIST.

&&

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

$$

SHORT TERM...BARJENBRUCH
LONG TERM....DANKERS
AVIATION/UPDATE...GIMMESTAD