Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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000
FXUS65 KBOU 252121
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
321 PM MDT WED MAR 25 2015

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 320 PM MDT WED MAR 25 2015

MAIN AREA OF PRECIPITATION ASSOCIATED WITH THE UPPER LEVEL TROUGH
HAS PUSHED SOUTH OF THE AREA. STILL EXPECT SCATTERED SNOW SHOWERS
THIS AFTERNOON...MAINLY OVER AND NEAR THE HIGHER TERRAIN. EXPECT
SHOWERS TO DECREASE THIS EVENING. A COUPLE OF THE HIGH RES MODELS
SHOW ACTIVITY THROUGH MID EVENING. THE FAVORABLE POSITION OF THE
JET WILL REMAIN OVERHEAD...THEREFORE WILL KEEP LOW POPS IN THE
FORECAST THROUGH MID EVENING. ADDITIONAL SNOWFALL AMOUNTS WILL BE
LIGHT...LESS THAN 2 INCHES OVER THE HIGHER TERRAIN AND LESS THAN
INCH ALONG THE LOWER ELEVATIONS.

EXPECT PARTIAL CLEARING TONIGHT ALONG WITH LIGHT WINDS. THIS SHOULD
ALLOW TEMPERATURES TO FALL INTO THE 20S OVERNIGHT.

A STRONG NORTH-NORTHWEST FLOW ALOFT WILL PREVAIL THURSDAY. A WAVE
WILL DROP SOUTH ACROSS THE NORTHERN PLAINS. ANY PRECIPITATION
ASSOCIATED WITH THE TROUGH OR JET IS EXPECTED TO STAY EAST OF
COLORADO. TEMPERATURES WILL BE WARMER ACROSS NORTHEAST COLORADO
WITH HIGHS IN THE MID 50S TO LOWER 60S EXPECTED. IT WILL BE WINDY
OVER THE PLAINS WITH GUSTS TO 40 MPH POSSIBLE DURING THE
AFTERNOON.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 320 PM MDT WED MAR 25 2015

DETERMINISTIC FCST MODELS SHOW THE HIGH AMPLITUDE WAVE TRAIN
PATTERN STRETCHED ACROSS THE NORTHERN PACIFIC FLATTENING OUT SOME
BY EARLY NEXT WEEK...RESULTING IN A MORE PROGRESSIVE FLOW AND WAVE
PATTERN OVER THE WESTERN CONUS. BEFORE THAT HAPPENS...STRONG LONG
WAVE RIDGE BUILDING ALONG THE WEST COAST NEXT 24 HOURS IS FORECAST
TO PROPAGATE EASTWARD OVER THE ROCKY MTN REGION BY EARLY THIS
WEEKEND. PRIOR TO ITS ARRIVAL...MODERATELY STRONG NWLY FLOW ALOFT
OVER NERN COLORADO WILL CONTINUE TO TRANSPORT RELATIVELY MOIST AND
UNSTABLE MID-LEVEL AIR OVER THE FCST AREA ON FRIDAY. WEAK
OROGRAPHIC LIFT AND MARGINALLY UNSTABLE LAPSE RATES MAY SPAWN A
FEW LATE DAY RAIN/SNOW SHOWERS OVER THE HIGHER NRN MTNS. OTHERWISE
FRIDAY LOOKS DRY AND WARMER AT LOWER ELEVATIONS WITH 15-25KT NWLY
SFC WINDS DVLPG ON THE NERN PLAINS BY AFTERNOON. BASED ON LATEST
TEMP GUIDANCE HIGHS ON FRIDAY SIGNIFICANTLY WARMER THAN THOSE ON
THURSDAY WITH AFTERNOON READINGS IN THE UPPER 60S TO LOWER
70S...AND IN THE 40S-MID 50S IN THE HIGH COUNTRY. FOR MOST AREAS
THAT/S 10-15 DEG F ABOVE AVERAGE FOR THE DATE.

GOING INTO THE WEEKEND...MODELS START OUT IN REASONABLY GOOD
AGREEMENT AS THEY SHOW THE WESTERN UPPER RIDGE PASSING OVER COLORADO
ON SATURDAY WITH ITS VERY WARM TEMPERATURES...LIGHT WINDS AND LOW
RELATIVE HUMIDITIES. RECENT PRECIP AND LIGHT WINDS SHOULD HOLD DOWN
THE WILDLAND FIRE RISK. BY SATURDAY NIGHT...UNITY IN THE MODELS
BEGINS TO BREAK DOWN AS THE EUROPEAN...NAM AND CANADIAN MODELS SHOW
THE UPPER RIDGE SHIFTING OUT OVER THE GREAT PLAINS AND A SHORTWAVE
TROUGH PACKING A RIBBON OF MOISTURE AND INSTABILITY RACING ACRS
WYOMING/NRN COLORADO HIGH COUNTRY SATURDAY NIGHT AND LOWER
ELEVATIONS OF NERN COLORADO SUNDAY MORNING. WILL GO WITH LOW PROBS
FOR RAIN/SNOW IN THE HIGH COUNTRY SAT NIGHT AND SUN...AND LOW PROBS
FOR THE PLAINS SUN MORNING FOLLOWING THE PASSAGE OF A WEAK SFC COLD
FRONT DURING THE PRE-DAWN HOURS. FOR THESE REASONS...TEMPS ON SUN
ABOUT 10 DEG F COOLER AS A RULE. MODEL SOLUTIONS CONTINUE TO DIVERGE
GOING INTO MONDAY AS THE EURO AND CANADIAN MODELS SHOW THE OPEN WAVE
SHORT WAVE SWINGS OUT OF COLORADO AND DRIER-STABLE AIR SWINGING DOWN
FROM WYOMING. WHEREAS...THE 12Z/GFS SHOWS AN UNCHARACTERISTICALLY
MOIST UPPER RIDGE SLOWLY MIGRATING OVER COLORADO AND A POTENT LITTLE
SHORTWAVE TROUGH PASSING OVER THE LAS VEGAS AREA DURING THE SUN
NIGHT-MON TIME PERIOD. OTHER MODELS BARELY INDICATE A RIPPLE IN THE
UPPER FLOW. FOR NOW...WILL STICK WITH A BLEND OF THE MODELS AND GO
WITH A SLIGHT CHANCE OF RAIN/SNOW SHOWERS IN THE HIGH COUNTRY AND
DRY CONDITIONS AT LOWER ELEVATIONS THROUGH WEDNESDAY ALONG WITH
SUBTLE DAY-TO-DAY CHANGES IN TEMPERATURE. HOPEFULLY LATER MODEL RUNS
WILL COME INTO BETTER AGREEMENT.

&&

.AVIATION...(FOR THE TAFS THROUGH 00Z THURSDAY LATE AFTERNOON)
ISSUED AT 320 PM MDT WED MAR 25 2015

LOW CEILINGS OF 2000 TO 5000 FEET ARE EXPECTED TO CONTINUE
THROUGH 03Z ALONG WITH ISOLATED SNOW SHOWERS. IF A SNOW SHOWER
PASSES OVER AN AIRPORT...VISIBILITY MAY BE REDUCED TO A QUARTER
MILE FOR A SHORT TIME. NORTHERLY WINDS WILL BECOME SOUTHERLY
AROUND 03Z.

CONDITIONS WILL IMPROVE AFTER 03Z...WITH CLOUDS RISING AND
SCATTERING BY 06Z. FOR THURSDAY...WILL SEE SCATTERED TO BROKEN
MID CLOUDS WITH CEILINGS ABOVE 6000 FEET. NORTHWEST WINDS WILL
BECOME GUSTY BY AFTERNOON WITH GUSTS TO 30 KNOTS POSSIBLE. AN
ANTICYCLONE COULD FORM AND CAUSE WINDS TO TURN EASTERLY AFTER
18Z.

&&

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

$$

SHORT TERM...MEIER
LONG TERM...BAKER
AVIATION...MEIER



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