Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 302213
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
413 PM MDT SUN AUG 30 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 400 PM MDT SUN AUG 30 2015

AT PRESENT TIME ...STILL BARELY UNDER THE INFLUENCE OF A STRONG/VERY
WARM AND MOSTLY DRY POSITIVE TILT UPPER RIDGE. 700-500 MB RIDGE AXIS
IS NOW SHIFTED EAST OF THE FRONT RANGE AS PER LATEST RAP MODEL WITH
FLOW ALOFT BECOMING WEST-SOUTHWESTERLY. UPSTREAM OVER UTAH/WESTERN
WYOMING...STRONGER SWLY FLOW ALOFT WITH AN 80-90KT JET CORE IS
PROGGED TO SLOWLY TRANSLATE EASTWARD OVER NORTHERN COLORADO NEXT 24
HOURS. MID/HIGH-LEVEL MOISTURE ALIGNED WITH THIS JET WILL SPREAD
OVER NORTH CENTRAL COLORADO TONIGHT AND NORTHEAST COLORADO ON
MONDAY. MODEL CROSS SECTIONS AND SOUNDINGS SHOW CONDENSATION LEVELS
LOWERING OVER THE HIGH COUNTRY AS A BAND OF SHOWERS AND T-STORMS
ALIGNED WITH A WEAK MID-LEVEL PERTABATION PASSES OVER THE AREA THIS
EVENING. AT THE SAME TIME THIS DISTURBANCE LIFTS EAST-NORTHEAST
ACROSS THE REMAINDER OF THE FORECAST AREA...SHOULD SEE A WEAK SFC
COLD FRONT SLIDING SOUTH OUT OF WYOMING. PRESSURE RISES BEHIND
THE FRONT DO NOT APPEAR TO BE ALL THAT STRONG AND WITH THE PRE-
FRONTAL ENVIRONMENT AS DRY AS IT IS...ITS PROBABLY NOT UNTIL NELY
BNDRY LAYER WINDS KICK IN AFTER FRONTAL PASSAGE WHEN PRECIP CHANCES
SHOULD GO UP EAST OF THE MTNS. AT THIS TIME...THE POORLY ORGANIZED
FRONT COULD SLIP INTO THE DENVER AREA BY 15Z TOMORROW MORNING...WITH
A RE-ENFORCING SURGE OF SLIGHTLY COOLER AND WETTER NELY FLOW BY
ABOUT MIDDAY. MOSTLY CLOUDY TO OVERCAST SKIES AND SCATTERED POPS ARE
IN ORDER FOR MONDAY. ONE OTHER ISSUE...THIS FRONTAL SURGE IS LIKELY
TO USHER IN THE NEXT BATCH OF WILDFIRE SMOKE FORM WILDFIRES TO OUR
NORTH AND NORTHWEST. NWS AIR QUALITY FORECAST GUIDANCE NOT
INDICATING MUCH IN THE WAY OF SFC AND COLUMN SMOKE ALONG THE FRONT
RANGE...BUT SHOULD ANY RESTRICTION DUE TO SMOKE ITS MORE LIKELY TO
OCCUR LATE IN THE DAY. TEMPERATURES QUITE MILD TONIGHT...WHEN COOLING
OFF BY SEVERAL DEGREES TOMORROW. EXPECT MAX TEMPS ON MONDAY TO
BE NEAR TO SLIGHTLY ABOVE AVERAGE.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 400 PM MDT SUN AUG 30 2015

CLOUDS AND SHOWERS/STORMS WILL GRADUALLY CLEAR FROM WEST TO EAST
MONDAY NIGHT. ON TUESDAY SLIGHT DRYING AND WARMING WILL LEAD TO
DIURNAL CONVECTION OVER THE MOUNTAINS THAT SHOULD PROGRESS NICELY
EASTWARD INTO THE EVENING. CAPES ARE RATHER LOW UNTIL YOU GET OUT
ON THE PLAINS...COULD BE A LOW THREAT OF SEVERE WIND/HAIL OUT EAST
IN THE EVENING.

DRIER AIR COMES IN WEDNESDAY. A LITTLE WIND IN THE MOUNTAINS
SHOULD PEAK TUESDAY NIGHT...BUT ENOUGH LEFT WEDNESDAY FOR ELEVATED
FIRE DANGER ESPECIALLY IN NORTH AND MIDDLE PARKS. THERE SHOULD BE
A MINIMUM OF CONVECTION ON WEDNESDAY AND ESPECIALLY THURSDAY WITH
THE WARMING ALOFT AND DRYING.

PRETTY GOOD MODEL AGREEMENT ON THE SOUTHWEST FLOW CONTINUING
THROUGH SATURDAY...WITH JUST A LITTLE MOISTURE POSSIBLY CREEPING
IN AT LOW LEVELS ON THE PLAINS AND ALOFT FROM THE SOUTHWEST. STILL
LOOKS RELATIVELY DRY OVERALL.

SOME DISAGREEMENT ON THE STRUCTURE OF THE TROUGH OVER THE
NORTHWEST AND SHORTWAVES MOVING ACROSS THE NORTHERN ROCKIES NEXT
WEEKEND...BUT NOT BAD FOR THAT TIME RANGE. MOST OF THE IMPACT IS
HEADED NORTH OF US...BUT IT SHOULD PUSH A SURGE OF COOLER AND
MOISTER...AND POSSIBLY SMOKIER...AIR SOMETIME THIS WEEKEND. THERE
ARE ALSO HINTS OF SOME SUBTROPICAL MOISTURE COMING UP FROM THE
EASTERN PACIFIC...BUT THIS MAY STAY SOUTH AND EAST OF US. THERE
COULD BE AN UPSWING IN CONVECTION FROM SUNDAY INTO EARLY NEXT WEEK
AS THE MOISTURE INCREASES...BUT WE WILL STILL BE FIGHTING THE
STABILITY FROM THE WARMTH ALOFT. MODELS SEEM TO KEEP MOST OF THE
PRECIPITATION FURTHER SOUTH. FOR NOW THE COOLING AND SLIGHT
INCREASE IN POPS FOR SUNDAY WILL DO...MAYBE MORE AFTER
THAT...MAYBE NOT.

&&

.AVIATION...(FOR THE TAFS THROUGH 00Z MONDAY LATE AFTERNOON)
ISSUED AT 400 PM MDT SUN AUG 30 2015

VISIBILITIES HAVE IMPROVED IN THE DENVER AREA TODAY WITH LIGHT
SWLY TRANSPORT WINDS AND EFFICIENT MIXING OF THE BOUNDARY LAYER
DUE TO STRONG HEATING TODAY. LATER TONIGHT...COULD SEE A GRADUAL
SHIFT TO LIGHT NORTHERLY WINDS WHICH MAY FUNNEL DOWN SOME SMOKE
POISED JUST NORTH OF THE WYOMING LINE. BEFORE THEN SOUTH-SOUTHEAST
WINDS WILL PREVAIL AT SPEEDS GENERALLY UNDER 12KTS. MEANWHILE THIS
EVENING STILL ANTICIPATING A T-STORM OR TWO TO MOVE OFF THE FRONT
RANGE FOOTHILLS. THESE HIGH BASED AND MOSTLY DRY STORM CELLS WILL
HAVE THE POTENTIAL TO PRODUCE GUSTS IN THE 25-30KT RANGE. LATER
TONIGHT...COULD SEE A FEW MORE LIGHT RAIN SHOWERS AND PERHAPS A
T-STORM OR TWO MOVING ACROSS THE AREA IN ADVANCE OF OF A WEAK
UPPER AIR DISTURBANCE AND SURFACE COLD FRONT. LATEST INDICATIONS
POINT TO A WEAK FRONTAL SURGE IN THE METRO AREA AROUND 15Z
TOMORROW MORNING...WITH A SOMEWHAT STRONGER PUSH OF SLIGHTLY
COOLER AND MOIST AIR ON NELY WINDS OF 15 TO 25KTS AROUND 18Z.
AFTER WHICH SHOULD SEE PRECIP CHANCES RISE IN THE METRO AREA WITH
SCATTERED SHOWERS AND ISOLATED T-STORMS. IN ADDITION...THE GUSTY
POST-FRONTAL WINDS COULD USHER IN MORE WILDFIRE SMOKE WHICH COULD
POSSIBLY LOWER VSBYS TO 5-6 MILE RANGE BY LATE AFTERNOON...ASSUMING
IT DOESN/T MIX OUT WITH THE SHOWERY PRECIPITATION.

&&

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

$$

SHORT TERM...BAKER
LONG TERM...GIMMESTAD
AVIATION...BAKER


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