954
FXUS65 KBOU 160158
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
758 PM MDT TUE APR 15 2025
KEY MESSAGES
- WARMER TEMPERATURES THROUGH THURSDAY.
- FIRE WEATHER CONCERNS THURSDAY, WITH THE HIGHEST PROBABILITIES
(60-80% CHANCE) OF CRITICAL CONDITIONS FROM SOUTH PARK &
SOUTHERN FOOTHILLS THROUGH EAST CENTRAL COLORADO.
- ACCUMULATING SNOW ALMOST CERTAIN (80-90% CHANCE) FOR THE
MOUNTAINS AND FOOTHILLS THURSDAY NIGHT - FRIDAY NIGHT, LIKELY
(60% CHANCE) FOR THE I-25 CORRIDOR BUT LIGHTER AMOUNTS, AND
LOWER CHANCES (20-40%) OVER THE EASTERN PLAINS.
- MUCH COLDER FRIDAY THROUGH SATURDAY, THEN GRADUAL MODERATION
THROUGH EARLY NEXT WEEK BUT STILL POTENTIALLY UNSETTLED.
UPDATE
ISSUED AT 757 PM MDT TUE APR 15 2025
WIDELY SCT VERY LIGHT SHOWERS/VIRGA WERE OVER THE HIGHER TERRAIN
AND PALMER DIVIDE EARLY THIS EVENING. EXPECT THIS ACTIVITY TO END
IN THE NEXT HOUR. OTHERWISE, NO CHANGES NEEDED TO FORECAST
OVERNIGHT.
SHORT TERM /THROUGH WEDNESDAY/
ISSUED AT 315 PM MDT TUE APR 15 2025
SATELLITE SHOWS CONVECTION IS LESS THAN IMPRESSIVE SO FAR, BUT NOW
FINALLY STARTING TO SEE A LITTLE BETTER MOISTURE ARRIVE FROM THE
SOUTHWEST. WE'LL SEE A CHANCE OF THESE SHOWERS MAKING IT INTO THE
AREA (MAINLY PARK COUNTY), BUT WOULDN'T EXPECT ANYTHING MORE THAN
VIRGA INTO DENVER THIS EVENING. WE'VE REDUCED POPS SLIGHTLY AND
CONFINED THEM TO THE MOUNTAINS ALONG/SOUTH OF I-70 AND THE PALMER
DIVIDE, BUT EVEN THERE DON'T EXPECT MUCH MORE THAN A PASSING
SPRINKLE.
THE LOW LEVELS REMAIN QUITE DRY THROUGH WEDNESDAY. THE MAIN BAND
OF MID/UPPER LEVEL MOISTURE WILL CONTINUE SPREADING NORTH ON THE
PERIPHERY OF THE UPPER LEVEL RIDGE. THUS, WE EXPECT JUST ISOLATED
TO SCATTERED HIGH BASED SHOWERS OVER THE MOUNTAINS, WITH AGAIN
JUST A FEW SPRINKLES SPILLING ONTO THE PLAINS. SOME OF THESE VIRGA
SHOWERS COULD PRODUCE GUSTY OUTFLOW WINDS WITH A WELL MIXED LOWER
TROPOSPHERE AND DCAPE NEAR 800 J/KG. TEMPERATURES WILL CONTINUE
THEIR WARMING TREND, WITH HIGHS ON THE PLAINS PUSHING THE UPPER
70S.
LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/
ISSUED AT 315 PM MDT TUE APR 15 2025
ISOLATED HIGH BASED SHOWERS WITH VERY LIGHT RAIN/SPRINKLES AND
GUSTY WINDS WILL GRADUALLY DISSIPATE AS WE HEAD THROUGH WEDNESDAY
EVENING.
THURSDAY IS SHAPING UP TO BE THE START OF AN ACTIVE WEATHER
PERIOD AS THE NEXT STORM SYSTEM DROPS SOUTH FROM THE NORTHERN
ROCKIES TOWARD THE GREAT BASIN. FIRST OFF, GUSTY WEST/SOUTHWEST
WINDS WILL BE STRENGTHENING AND HUMIDITIES DROPPING IN THE
PREFRONTAL AIRMASS, LEADING TO FIRE WEATHER CONCERNS - MORE ON
THAT BELOW. A STRONG COLD FRONT WILL ARRIVE DURING THE DAY AS
WELL. WE LIKED THE SLIGHTLY EARLIER ARRIVAL OF THE FRONT ACROSS
THE PLAINS (MID-LATE MORNING NORTHERN BORDER AND LATE AFTERNOON
CREST OF PALMER DIVIDE). OVERALL TEMPERATURES WILL STILL BE QUITE
MILD AND ABOVE NORMAL FOR HIGHS, BUT STRONG COLD ADVECTION OCCURS
WITH TEMPERATURES FALLING IN THE AFTERNOON - AS LONG AS THE FRONT
ARRIVES AS EXPECTED. THERE'S STILL A LOW CHANCE (20-30%) THAT THE
FRONT HOLDS OFF UNTIL LATE IN THE DAY.
THAT FRONT, COMBINED WITH WEAK QG LIFT, SET THE STAGE FOR
PRECIPITATION DEVELOPMENT FOR THURSDAY AFTERNOON AND EVENING. THE
SHOWERS, AND EVEN A COUPLE THUNDERSTORMS, WILL FIRST DEVELOP IN
THE MOUNTAINS AND THEN SPREAD EAST AND EVENTUALLY SOUTHWARD ACROSS
THE PLAINS DURING THE LATE AFTERNOON AND EVENING. THE FOCUS FOR
THE MORE SIGNIFICANT PRECIPITATION AMOUNTS BY THURSDAY NIGHT AND
FRIDAY WILL BE IN/NEAR THE FRONT RANGE MOUNTAINS AND FOOTHILLS
WITH THE WEAK UPSLOPE COMPONENT DEVELOPING BEHIND THE FRONT AND
ONLY WEAK SYNOPTIC SCALE LIFT. THERE IS STILL SOME UNCERTAINTY
WITH REGARD TO WHERE THE UPPER LEVEL LOW SETTLES, BUT GUIDANCE HAS
GENERALLY BECOME BETTER ALIGNED TO A POSITION NEAR THE
UTAH/ARIZONA BORDER BY LATE FRIDAY. IF THAT WAS TO MOVE CLOSER TO
THE FOUR CORNERS INITIALLY, WE'D BE LOOKING AT MORE SIGNIFICANT
PRECIPITATION. BUT AT THE SAME TIME THERE ARE OTHER OUTLIERS THAT
TAKE THE UPPER LOW FARTHER SOUTH AND WEST, AND THESE WOULD
SUPPORT ONLY LIGHT PRECIPITATION AMOUNTS. WE'LL STILL RELY ON THE
ENSEMBLE AVERAGES AT THIS POINT GIVEN SOME CONVERGENCE IN THE
MIDDLE GROUND. TEMPERATURES HAVE CONTINUED TO TREND COLDER, GIVING
SOME SUPPORT FOR MORE SNOW ACCUMULATION EVEN INTO THE LOWER
ELEVATIONS. SPRING EVENTS ARE ALWAYS TRICKY, AS NIGHT-TIME
ACCUMULATIONS ARE MUCH MORE LIKELY THAN DAYTIME CONSIDERING THE
RELATIVELY HIGH APRIL SUN ANGLE AND SOLAR INSOLATION. WE DO THINK
ROADS WOULD REMAIN WET BELOW 6,000 FEET (URBAN AREAS), BUT
IMPACTS LIKELY STARTING THURSDAY NIGHT FOR THE MOUNTAINS AND
FOOTHILLS, AND POSSIBLY EVEN THE PALMER DIVIDE GIVEN THE COLDER
TRENDS IN PLACE. WINTER HIGHLIGHTS WILL LIKELY BE REQUIRED IN
LATER UPDATES. IT SHOULD BE NOTED IF THERE IS ADDITIONAL COOLING,
THEN SOME IMPACTS TO RECENTLY LEAFED OUT TREES AND SHRUBS WILL BE
POSSIBLE FOR THE METRO AREA, BUT ODDS ARE RELATIVELY LOW YET AT
THIS POINT AT LEAST IF THE MORE SIGNIFICANT PRECIPITATION FALLS
DURING THE DAY FRIDAY.
MODELS GENERALLY SHOW PRECIPITATION RATES DECREASING FRIDAY NIGHT
INTO SATURDAY MORNING FROM NORTH TO SOUTH ACROSS THE AREA AS THE
UPPER LOW AND SYNOPTIC SUPPORTS SINKS SLIGHTLY FARTHER SOUTH. BUT
THAT'S NOT CERTAIN EITHER WITH A FEW SOLUTIONS STARTING TO EJECT
THE UPPER LOW A BIT FARTHER NORTH.
SUNDAY TO MONDAY WILL SEE A MORE WESTERLY FLOW ALOFT DEVELOP AND
SHORTWAVE RIDGING EXPECTED BY MONDAY. THIS WILL LEAD TO A WARMING
TREND WITH HIGHS CLOSER TO NORMAL ONCE AGAIN. THERE COULD STILL BE
A FEW DAILY SHOWERS BUT MOSTLY IN THE MOUNTAINS.
THERE IS GOOD AGREEMENT IN THE ENSEMBLES THAT ANOTHER SHORTWAVE
WILL PUSH ACROSS THE FORECAST AREA BY TUESDAY OR WEDNESDAY, SO
GENERALLY AN ACTIVE SPRING-LIKE PATTERN WILL PERSIST THROUGH THE
MIDDLE OF NEXT WEEK.
AVIATION /00Z TAFS THROUGH 00Z THURSDAY/
ISSUED AT 514 PM MDT TUE APR 15 2025
ENE WINDS WILL GRADUALLY BECOME MORE SE BY 01Z AND THEN TRANSITION
TO SSW BY 04Z. BY 16Z WED, WINDS WILL BECOME MORE WESTERLY AND
THEN SWITCH TO NW BY 19Z. VFR CONDITIONS WILL CONTINUE THRU THE
PERIOD.
FIRE WEATHER
ISSUED AT 315 PM MDT TUE APR 15 2025
IT WILL BE WARMER AND DRIER WEDNESDAY, BUT WINDS WILL REMAIN
RELATIVELY LIGHT. IT WILL BE BREEZY NEAR THE WYOMING BORDER
HOWEVER, ENOUGH FOR ELEVATED FIRE WEATHER CONCERNS THERE.
MORE SIGNIFICANT FIRE WEATHER CONDITIONS ARE EXPECTED THURSDAY AS
WINDS INCREASE. THERE'S HIGH CONFIDENCE WE'LL SEE GUSTY WINDS
DEVELOP, AND HUMIDITIES DROP TO LESS THAN 15% - ESPECIALLY FROM
SOUTH PARK INTO THE FOOTHILLS AND PLAINS ALONG AND SOUTH OF I-70.
THAT'S WHERE PREFRONTAL WINDS WILL GUST TO 35-45 MPH IN A WELL
MIXED AND VERY DRY AIRMASS. THEREFORE, WE'VE ISSUED A FIRE WEATHER
WATCH FOR THOSE AREAS. FARTHER NORTH, THE FRONT COULD VERY WELL
OOZE IN EARLIER IN THE DAY, KEEPING THE FIRE WEATHER THREAT LOWER
(ONLY A 20-40% CHANCE OF CRITICAL FIRE WEATHER CONDITIONS. WE WILL
CONTINUE TO MONITOR.
BOU WATCHES/WARNINGS/ADVISORIES
FIRE WEATHER WATCH FROM THURSDAY MORNING THROUGH THURSDAY
EVENING FOR COZ214-216-240-241-245>247.
UPDATE...RPK
SHORT TERM...BARJENBRUCH
LONG TERM...BARJENBRUCH
AVIATION...RPK
FIRE WEATHER...BARJENBRUCH
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page