Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS65 KBOU 282047
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
247 PM MDT SAT MAR 28 2015

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 247 PM MDT SAT MAR 28 2015

UPPER LEVEL SHORTWAVE TROUGH IN TANDEM WITH A SFC COLD FRONT NOW
MAKING THEIR WAY ACROSS NWRN WYOMING AND NRN UTAH. DO NOT SEE MUCH
IN THE WAY OF MOISTURE/PCPN WITH THIS SYSTEM ATTM...AND QG
VERTICAL VELOCITY FIELDS ARE INDICATING ONLY MODEST DEEP LAYER
ASCENT BEHIND THE SFC FRONT. DETERMINISTIC MODELS AND SYNTHETIC
SATELLITE IMAGERY SHOW THIS UPPER AIR FEATURE RACING SEWRD ACRS
WYOMING EARLY THIS EVENING AND DOWN ACRS N-CNTRL AND NERN COLORADO
OVERNIGHT. MEANWHILE MODELS DIFFER ON THE ARRIVAL TIME OF THE SFC
FRONT. WRF...RAP...GFS...ECMWF AND CANADIAN MODELS ALL SHOW BNDRY
LAYER WINDS ON THE PLAINS TURNING GUSTY FROM THE NORTHWEST WITH
FRONTAL PASSAGE LATE THIS EVENING. WHEREAS THE NAM DELAYS THE
ARRIVAL OF THE FRONT AND ITS WIND SHIFT UNTIL SOMETIME BETWEEN
06Z AND 09Z. MOST OF THESE SAME MODELS SHOW A NARROW BAND OF LOW-
LEVEL CONVERGENCE AND STEEP LAPSE RATES ACROSS THE NORTHEAST
PLAINS LATE THIS EVENING AND HINTS OF A TRIPLE POINT JUST BEYOND
THE NERN CORNER OF THE STATE JUST AHEAD OF THE COLD FRONT. CROSS
SECTIONS AND MODEL SOUNDINGS SHOW MID-LEVELS SATURATING WITH WEAK
QG ASCENT SUFFICIENTLY TO GENERATE A FEW HIGH BASED SHOWERS AND
PERHAPS A WEAK SHORT-LIVED T-SHOWER OVER THE NERN CORNER.
OTHERWISE ONLY GUSTY N-NWLY WINDS...FALLING TEMPERATURES AND
RISING HUMIDITIES UNDER MOSTLY CLEAR/PARTLY CLOUDY SKIES EXPECTED
WITH PASSAGE OF THIS WEAK SYSTEM...AND PERHAPS A FEW LIGHT SNOW
SHOWERS OVER THE NRN MTN RANGES.

SUNDAY...LOOKS DRY AND COOLER WITHIN THE POST-FRONTAL ENVIRONMENT
WITH GUSTY NLY WINDS ON THE PLAINS AND STG/GUSTY NWLY WINDS IN
THE FRONT RANGE MTNS DURING THE MORNING HOURS. FLOW ALOFT WEAKENS
DURING THE AFTERNOON AS THE UPPER RIDGE BUILDING OUT WEST MOVES
CLOSER TO THE STATE. SHOULD THEN SEE WIND SPEEDS SUBSIDING EVEN IN
THE HIGH COUNTRY WITH HARDLY A CLOUD IN THE SKY WITH STG MID-
LEVEL SUBSIDENCE. HIGHS TOMORROW ARE EXPECTED TO RUN 10-15 DEG F
BELOW THOSE OBSERVED TODAY. THAT/S STILL ABOVE AVERAGE FOR THE
DATE.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 247 PM MDT SAT MAR 28 2015

A RELATIVELY DRY AND WARM PERIOD THROUGH NEXT WEDNESDAY WITH RIDGE
OF HIGH PRESSURE ALOFT OVER PORTIONS OF THE WESTERN U.S.  THE
RIDGE WILL SHIFT INTO THE PLAINS BY MID WEEK AS FLOW SHIFTS WEST
AND SOUTHWEST FOR WEDNESDAY AND THURSDAY. TEMPERATURES WILL BE WAY
ABOVE NORMAL WITH READINGS IN THE 70S ACROSS LOWER ELEVATIONS
THROUGH WEDNESDAY. THERE IS ONLY A SLIGHT CHANCE OF AFTERNOON AND
SHOWERS IN THE MOUNTAINS...MAINLY SOUTH OF INTERSTATE 70 AND
ACROSS PARK COUNTY WITH A BIT BETTER MOISTURE THERE.

AS THE FLOW TURNS ZONAL ON WEDNESDAY THERE IS A WEAK FRONTAL
BOUNDARY WHICH MOVES THROUGH WEDNESDAY AM ALONG WITH A SLIGHT
CHANCE OF SHOWERS. A STRONGER SYSTEM DEVELOPS OVER THE GREAT BASIN
ON THURSDAY BEFORE SLOWLY SHIFTING ACROSS COLORADO SOMETIME IN THE
LATE THURSDAY AND FRIDAY TIME FRAME. THERE ARE SOME TIMING DIFFERENCES
BETWEEN EUROPEAN AND GFS SOLUTION SO FOR NOW WILL JUST KEEP LOW
POPS AND COOLER TEMPERATURES.

&&

.AVIATION...(FOR THE TAFS THROUGH 00Z SUNDAY LATE AFTERNOON)
ISSUED AT 247 PM MDT SAT MAR 28 2015

LOOK FOR GUSTY WESTERLY WINDS AT KBJC AND KDEN FOR THE REMAINDER
OF THE AFTERNOON UNDER MOSTLY CLEAR SKIES. GUSTS WILL RUN IN THE
15-25KT RANGE. AFTERNOON WINDS AT KAPA WILL BE MUCH LIGHTER FROM
A NWLY DIRECTION. BY NIGHT FALL WIND SPEEDS SHOULD QUICKLY FALL
OFF AS WINDS SHIFT TO A SOUTHWESTERLY COMPONENT. HOWEVER BY LATE
EVENING...SKIES WILL BEGIN FILLING WITH MID-LEVEL CUMULUS TYPE
CLOUDS WITH THE APPROACH OF A WEAK UPPER LEVEL TROUGH AND SFC
COLD FRONT. LATEST INDICATIONS POINT TO A FRONTAL PASSAGE IN
DENVER AROUND 06Z. AT THIS TIME DO NOT EXPECT TO SEE ANY PCPN
OR LOW CLOUDS WITH ITS PASSAGE AS THE AIR BEHIND THIS FRONT IS
ALSO DRY BUT COOLER. ON SUNDAY...STRONG NORTHWEST FLOW ALOFT IS
EXPECTED TO PRODUCE NORTH-NORTHEAST SFC WINDS OF 12-22KT AT KDEN
AND KAPA PRIOR TO 18Z. NLY WIND AT KBJC ARE NOT EXPECTED TO BE AS
STRONG BUT COULD SEE A FEW LOWER CLOUDS FORM BY AROUND 15Z. REST
OF THE DAY...WINDS WEAKEN AND TURN ELY UNDER NEARLY CLOUDLESS
SKIES.

&&

.FIRE WEATHER...
ISSUED AT 247 PM MDT SAT MAR 28 2015

FIREWEATHER ZONE 238..239 AND 242 REMAIN IN A RED FLAG WARNING
OUNTIL 1800 MDT. GUSTY WEST WINDS...LOW RELATIVE HUMIDITY AND
ABNORMALLY WARM TEMPERATURES WILL COMBINE WITH DRY FUEL CONDITIONS
TO PRODUCE POTENTIALLY CRITICAL RANGELAND FIRE BEHAVIOR THIS
AFTERNOON. LIGHTER WINDS...COOLER TEMPERATURES AND GRADUAL RH
RECOVERY CAN BE EXPECTED THIS EVENING.

.BOU WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 6 PM MDT THIS EVENING FOR COZ238-239-242.

&&

$$

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


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.