Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 182124
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
324 PM MDT SAT OCT 18 2014

.SHORT TERM...(THIS AFTERNOON THROUGH SUNDAY)
ISSUED AT 324 PM MDT SAT OCT 18 2014

500 MB LOW WAS SPINNING ITS WAY EWRD ACROSS NORTHEAST NEW MEXICO
ATTM...WITH 700 MB LOW OVER THE COLORADO/NEW MEXICO LINE NEAR
TRINIDAD. BOTH WERE RESPONSIBLE FOR THE EXPANDING CLOUD SHIELD
OVER THE SOUTHERN TWO-THIRDS OF COLORADO THIS AFTERNOON. NAMNEST
IR SYNTHETIC SATELLITE IMAGERY INDICATES AN INCREASE IN CLOUD
COVER OVER THE MTNS AND HIGH VALLEYS OVER THE NEXT FEW HOURS AS
THE BAROCLINIC CLOUD LEAF ASSOCIATED WITH AN EASTWARD PROPAGATING
MID-LEVEL SHORTWAVE TROUGH NOW OVER SOUTHWEST COLORADO. MODELS
SHOW THE BULK OF THE MOISTURE WITH THIS FEATURE REMAINING ALONG
AND SOUTH OF THE COLORADO/NEW MEXICO STATE LINE. HOWEVER...ENOUGH
OF THIS MOISTURE HAS SPREAD NORTHWARD OVER THE FRONT RANGE WHERE
LOW TOP CONVECTION WAS UNDERWAY. RADAR HAS YET TO DETECT ANY
PCPN...BUT PROBABLY ANY TIME NOW. STILL...BEST CHANCE FOR
SHOWERS/T-SHOWERS THROUGH 02Z THIS EVENING SOUTH OF INTERSTATE 70
AND MAINLY OVER THE HIGHER TERRAIN IN PARK...SUMMIT...CLEAR CREEK
AND GILPIN COUNTIES. PCPN AMOUNTS SHOULD BE LIGHT AND GUSTY
OUTFLOW WINDS A PRETTY GOOD BET. CHANCE OF PCPN IN THESE AREAS
GENERALLY IN THE 15 TO 30 PERCENT RANGE. THIS JIVES WITH
REFLECTIVITY PLOTS OFF THE NAM...HRRR AND WRF-ARW. WHEREAS...DO
NOT SEE ANY SHOWER ACTIVITY ON THE PLAINS WHERE ENVIRONMENT TOO
DRY AND STABLE EVEN WITH THE LIGHT UPSLOPE FLOW IN PLACE ALONG THE
FOOTHILLS. FARTHER OUT ON THE PLAINS...A RELAXING PRESSURE
GRADIENT HAS RESULTED IN LIGHTER SLY SFC WINDS OVER THE PAST HOUR
OR SO.

TONIGHT...MODELS SHOW THE ABOVE MENTIONED SHORTWAVE EXITING THE
STATE AROUND MIDNIGHT WITH FLOW ALOFT BECOMING WEST-NORTHWESTERLY.
THIS LEADS TO FURTHER DRYING EAST OFF THE MTNS...BUT AN INCREASE
IN CLOUD COVERAGE ALONG AND WEST OF THE CONTINENTAL DIVIDE.
STRENGTHENING MID-LEVEL INVERSION OVERNIGHT WILL LIMIT SHOWER
DEVELOPMENT IN THE HIGH COUNTRY TO JUST THE EVENING HOURS. AFTER
MIDNIGHT SHOULD SEE A GRADUAL REDUCTION IN CLOUDS FROM WEST-TO-
EAST WITH AN UPPER RIDGE BUILDING OVER THE EASTERN GREAT BASIN.
LOW TEMPERATURES TONIGHT ABOUT AVERAGE FOR THE DATE.

ON SUNDAY...THE UPPER RIDGE OVER UTAH IS FCST TO SHIFT EAST OVER
COLORADO DURING THE DAY. SOUTHERLY LOW/MID-LEVEL FLOW ON THE
PACIFIC SIDE OF THIS RIDGE LOOKS TO FUNNEL ANOTHER BATCH OF
SUBTROPICAL MOISTURE UP OVER WESTERN AND SOUTHERN SECTIONS OF
THE STATE. AS WAS THE CASE TODAY...MAY SEE SOME OF THIS MOISTURE
SPREADING OVER OUR MTN AND FOOTHILL COUNTIES BY EARLY AFTERNOON...
LEADING TO ISOLATED TO SCATTERED SHOWERS/T-STORMS. MEANWHILE...
EAST OF THE MTNS...NORTHWEST FLOW ALOFT MIXES DOWNWARD THROUGH THE
DAY TO PRODUCE NELY/UPSLOPE WINDS ON THE PLAINS. COULD SEE A SHIFT
TO NORTH-NORTHEAST WINDS ON THE PLAINS NOT LONG AFTER SUNRISE.
PLAINS AIRMASS REMAINS CAPPED. SO PRECIP CHANCES LESS THAN 10
PCT. HOWEVER ITS POSSIBLE THE FOOTHILLS AND WESTERN PORTIONS OF
THE PALMER DIVIDE COULD SEE A STRAY SHOWER OR TWO FORM IN THE
AFTERNOON. SHOULD SEE WARMER TEMPERATURES TOMORROW WITH HIGHS
GENERALLY 3-5 DEG F HIGHER THAN TODAY.


.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 324 PM MDT SAT OCT 18 2014

A WEAK DISTURBANCE MOVING SOUTH FROM THE NORTHERN GREAT PLAINS
WILL PUSH IN SLIGHTLY COOLER AIR SUNDAY NIGHT OVER NORTHEASTERN
COLORADO. A FEW SHOWERS MAY REMAIN OVER THE CENTRAL MOUNTAINS
SUNDAY EVENING...BUT WILL DISSIPATE QUICKLY WITH THE LOSS OF THE
SUNS HEAT. WARMER TEMPERATURES WILL FOLLOW MONDAY WITH MOSTLY
CLEAR SKIES AND STRENGTHENING SOUTHERLY WINDS OVER THE PLAINS AS A
SURFACE TROUGH DEEPENS OVER THE LEE OF THE ROCKIES.

A PACIFIC SYSTEM WILL PUSH IN OVER THE WESTERN STATES TUESDAY
TURNING FLOW ALOFT SOUTHWEST OVER COLORADO WITH INCREASING HIGH
CLOUDS. TEMPERATURES ARE EXPECTED TO WARM EVEN MORE AND SOUTH
WINDS WILL CONTINUE TO BE GUSTY OVER THE EASTERN PLAINS. SCATTERED SHOWERS
AND A FEW THUNDERSTORMS ARE EXPECTED OVER THE HIGH COUNTRY IN THE
AFTERNOON AND EVENING AHEAD OF THE SYSTEM. ENOUGH MOISTURE AND WEAK
UPWARD QG VERTICAL VELOCITIES MAY HELP SHOWERS CONTINUE OVER THE
HIGH TERRAIN OVERNIGHT.

THE PACIFIC SYSTEM WILL PASS OVER THE STATE WEDNESDAY WITH THE
ASSOCIATED COLD FRONT EXPECTED IN THE MORNING. HIGH TEMPERATURES
SHOULD BE ABOUT 10 DEGREES COOLER WEDNESDAY...BACK NEAR AVERAGE
FOR THIS TIME OF YEAR. SHOWERS WILL SPREAD ACROSS THE AREA WITH
SOME THUNDERSTORMS POSSIBLE AS THE UPPER TROUGH MOVES ACROSS THE
STATE. SNOW LEVELS ARE EXPECTED TO LOWER TO AROUND 8500 FEET
WEDNESDAY EVENING BEFORE THE SYSTEM EXITS QUICKLY SOUTHEAST AND
PRECIPITATION WILL HAVE PRETTY MUCH ENDED BY OR JUST AFTER
MIDNIGHT. MODELS HAVE BACKED OFF ON THE AMOUNTS OF PRECIP...AND
IN SOME CASES ANY CHANCE OF PRECIP OVER THE PLAINS. DO NOT FEEL
COMFORTABLE WITH NO CHANCE AT THIS POINT...WILL MAKE SURE THERE IS
AT LEAST A SLIGHT CHANCE AND WILL INCREASE THE CHANCE OVER THE
MOUNTAINS AS IT SEEMS TO BE UNDERDONE AS WELL.

UPPER RIDGING BUILDS BACK IN FOR THE REST OF THE WEEK AND INTO THE
WEEKEND FOR DRY WEATHER AND WARMER THAN NORMAL TEMPERATURES FOR
THIS TIME OF YEAR.

&&

.AVIATION...(FOR THE TAFS THROUGH 18Z SUNDAY MORNING)
ISSUED AT 324 PM MDT SAT OCT 18 2014

WINDS AT DENVER AREA TERMINALS HAVE GONE EAST-NORTHEASTERLY IN
THE PAST HOUR OR TWO AND SHOULD REMAIN THAT WAY FOR THE NEXT FEW
HOURS. THEN A GRADUAL RETURN TO A SELY COMPONENT BEFORE SUNSET...
THEN SOUTH-SOUTHWESTERLY AFTER DARK. SPEEDS WILL GENERALLY REMAIN
UNDER 8KTS ALTHOUGH AS THEY BECOME SELY COULD SEE SPEEDS UP
AROUND 14KTS AT DIA AND APA. ON SUNDAY...LIGHT DRAINAGE WINDS
EARLY SHIFT TO NORTHERN BY MID-MORNING...THEN NORTHEASTERLY BY
MIDDAY IF NOT SOONER AT SPEEDS OF 7-14KTS. OTHERWISE OVER THE NEXT
24 HOURS...SHOULD SEE PERIODS OF MID AND HIGH-LEVEL CLOUDS WITH
ESSENTIALLY NO CHANCE OF PRECIP IN THE DENVER AREA.

&&

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

$$

SHORT TERM...BAKER
LONG TERM...KRIEDERMAN
AVIATION...BAKER



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