National Weather Service Weather Forecast Office

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

000
FXUS65 KBOU 200941
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
341 AM MDT THU JUN 20 2013

.SHORT TERM...THE BROAD UPPER LOW REMAINS OVER THE PACIFIC
NORTHWEST AND NORTHERN ROCKIES RESULTING IN A CONTINUED SOUTHWEST
FLOW PATTERN ACROSS COLORADO. THE AIRMASS IS QUITE DRY SO NO
THUNDERSTORMS ARE EXPECTED TODAY OR TONIGHT. WEAK SURFACE FRONT
PUSHING SOUTHWARD OVER THE NORTHEAST PLAINS EARLY THIS MORNING AND
WILL BE THROUGH MOST OF NE COLORADO BY 15Z. THIS WILL PUSH THE
SURFACE LOW INTO WESTERN KANSAS BY AFTERNOON WHILE EVEN DRIER LOW
LEVEL AIR IS BEHIND THIS FRONT WITH DEWPOINTS DROPPING INTO THE
TEENS AND 20S OVER SOUTHERN WYOMING. THERE IS A BIT OF COOLER AIR
BEHIND THE FRONT AS WELL SO HIGHS TODAY WILL BE A LITTLE
LOWER...GENERALLY 3-5 DEGREES COOLER THAN WEDNESDAY HIGHS. LOW
LEVEL MOISTURE WILL BE A BIT HIGHER TOWARDS THE KANSAS AND
NEBRASKA BORDERS BUT EVEN THEN...AIRMASS LOOKS TOO CAPPED FOR ANY
STORMS OUT THERE.

.LONG TERM...OPERATIONAL MODELS CONTINUE TO SHOW AN UPPER TROUGH
MIGRATING OH SO SLOWLY EASTWARD OVER THE PACIFIC NORTHWEST AND
NORTHERN ROCKY MTN REGIONS DURING THE FRIDAY-SUNDAY TIME FRAME.
MODELS APPEAR TO BE IN GENERALLY GOOD AGREEMENT ESPECIALLY WITH
LARGE SCALE FEATURES. ON FRIDAY...THE 500 MB TROUGH AXIS IS
PROGGED TO BE OVER THE WASHINGTON/OREGON/IDAHO LINE WITH MODERATE
SOUTHWESTERLY FLOW ALOFT DOWNSTREAM OVER COLORADO. AT LOWER
LEVELS...LIGHT/VARIABLE WINDS IN THE MORNING ACROSS THE CWFA ALIGN
WITH THE STRONGER SWLY FLOW ALOFT WITH STRONG DIABATIC HEATING
LATER IN THE DAY. STRONGEST SOUTH-SOUTHWESTERLY SFC WINDS ARE
EXPECTED ACROSS SERN PORTIONS OF THE FORECAST AREA WHERE GUSTS TO
AROUND 25 KTS ARE POSSIBLE. THE COMBINATION OF VERY LOW RH
VALUES...DRY FUELS...STEEP BOUNDARY LAYER LAPSE RATES AND THESE
GUSTY WINDS MAKE IT NECESSARY TO ISSUE A FIRE WEATHER WATCH FOR
THIS AREA...SPECIFICALLY FOR FIRE WEATHER ZONES 214 AND 241. KEPT
EASTERN ELBERT/LINCOLN COUNTY FIRE WX ZONES 246/247 OUT OF THE
WATCH...AT LEAST FOR NOW...BECAUSE OF THE RECENT WETTING RAINFALL
IN THIS AREA. ISOLATED GUSTY T-STORMS ALSO A POSSIBILITY OVER THE
HIGHER SLOPES/RIDGES OF THE FRONT RANGE MTNS AND FAR NORTHEAST
CORNER OF THE STATE WHERE LOW-LEVEL MOISTURE WILL BE MORE
PLENTIFUL. MAX TEMPERATURES ON FRIDAY SHOULD GENERALLY BE 4-5C
ABOVE AVERAGE FOR THE DATE.

FOR THE REMAINDER OF THE EXTENDED PERIOD...SHOULD SEE SUBTLE DAY-TO-
DAY CHANGES IN TEMPERATURE UNDER CLEAR TO PARTLY CLOUDY SKIES.
HOWEVER AS THE UPPER TROUGH REFERRED TO ABOVE LIFTS NEWRD OVER THE
NORTHERN GREAT PLAINS ON SUNDAY...A WEAK COLD FRONT IS FCST TO SLIDE
SOUTH ACROSS NERN COLORADO EARLY IN THE DAY RESULTING A 3-4C DROP IN
TEMPERATURES FROM THE DAY BEFORE. MAY ALSO SEE A WEAK T-STORM OR TWO
POP IN THE FAR NERN CORNER OF THE STATE LATE IN THE DAY. OTHERWISE
IT SHOULD CONTINUE TO BE QUITE DRY. THE TROUGH MOVES OUT ALLOWING
ANOTHER UPPER TROUGH TO DROP IN OVER THE PACIFIC NORTHWEST ON
MONDAY. THIS PUTS NORTH CENTRAL/NORTHEAST COLORADO UNDER A VERY
WARM AND DRY SOUTHWEST FLOW AGAIN. BY TUESDAY...MODELS SHOW THIS
TROUGH WEAKENING AND RACING EAST ACROSS THE NORTHERN ROCKIES WITH
LITTLE IMPACT ON OUR WEATHER. BY MIDWEEK...MEDIUM RANGE MODELS
INDICATE A LARGE DOME OF HOT AND DRY AIR CENTERING OVER SOUTHWEST
COLORADO. AT PRESENT TIME MOS TEMPERATURE GUIDANCE IS INDICATING
MAX TEMPERATURES AT LOWER ELEVATIONS IN THE LOW/MID 90S ON
WEDNESDAY. HOWEVER SHOULD THIS RIDGE OF HOT AIR SET UP A BIT
FARTHER EAST...WE MAY ONCE AGAIN SEE READINGS AROUND THE 100 DEG
MARK ON THE PLAINS.

&&

.AVIATION...OBS AT APA/DEN CONTINUE TO SHOW SOME SMOKE REDUCING
VISIBILITIES AT TIMES FROM FIRES ACROSS SOUTHERN COLORADO.
FRONTAL BOUNDARY TO THE NORTH SHOULD MOVE THORUGH TERMINALS
BETWEEN 11-12Z AND SHOULD SUPPRESS THE SMOKE LAYER BACK TO THE
SOUTH AND RESULT IN IMPROVING VISIBILITIES. BEHIND THE
FRONT...SURFACE WINDS WILL SHIFT NORTHERLY...THEN MORE EAST AND
SOUTHEAST THIS AFTERNOON. AIRMASS WILL BE VERY DRY SO NO
THUNDERSTORMS ARE EXPECTED.

&&

.FIRE WEATHER...WILL CONTINUE WITH THE EARLIER ISSUED RED FLAG
WARNINGS FOR MOUNTAIN VALLEYS...PARK COUNTY AND PALMER DIVIDE THIS
AFTERNOON. THE STRONGER SW FLOW ALOFT WILL MIX TO THE SURFACE THIS
AFTERNOON RESULTING IN GUSTY SOUTHWEST WINDS AND VERY LOW RH
LEVELS BELOW 10 PERCENT. MORE OF THE SAME FOR FRIDAY
AFTERNOON...HENCE THE FIRE WEATHER WATCH FOR SOUTHERN PORTIONS OF
CWA.

&&

.HYDROLOGY...NO ISSUES.


&&

.BOU WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON TODAY TO 8 PM MDT THIS EVENING FOR
COZ211-213-214-241.

FIRE WEATHER WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING
FOR COZ214-241.

&&

$$

SHORT TERM...ENTREKIN
LONG TERM....BAKER
AVIATION...ENTREKIN