265
FXUS65 KBOU 230931
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
331 AM MDT WED OCT 23 2024
KEY MESSAGES
- DRY WITH ABOVE NORMAL TEMPERATURES THROUGH THURSDAY. INCREASING
WINDS AND AT LEAST ELEVATED FIRE WEATHER CONDITIONS THURSDAY DUE
TO A FAST MOVING DISTURBANCE AND COLD FRONT.
- SLIGHTLY COOLER TEMPERATURES LATE THURSDAY INTO FRIDAY, THOUGH
TEMPERATURES WILL STILL REMAIN NEAR OR ABOVE NORMAL.
- PATTERN CHANGE LIKELY EARLY NEXT WEEK. HIGH PROBABILITIES OF
BELOW NORMAL TEMPERATURES BEYOND TUESDAY (>70%), AND A CHANCE
FOR THE FIRST WINTRY WEATHER ACROSS THE PLAINS BY MID-WEEK.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 243 AM MDT WED OCT 23 2024
DRY WESTERLY FLOW ALOFT WILL BE OVER THE AREA TODAY. A WEAK COOL
FRONT THAT AFFECTED THE PLAINS LAST EVENING WILL WASH OUT LATER THIS
MORNING INTO THE AFTN. THIS WILL ALLOW FOR INCREASING SOUTHERLY LOW
LEVEL FLOW ACROSS THE PLAINS THIS AFTN. AFTN HIGHS WILL BE SLIGHTLY
COOLER AS READINGS RANGE FROM THE MID 60'S OVER THE FAR NERN PLAINS
WITH LOWER TO MID 70'S ALONG THE I-25 URBAN CORRIDOR.
FOR TONIGHT, THE FLOW ALOFT WILL BECOME MORE WSW AS A QUICK MOVING
UPPER LEVEL TROUGH APPROACHES FROM THE NW. ANY MOISTURE WITH THIS
FEATURE WILL NOT AFFECT THE NRN MTNS UNTIL AFTER 12Z THU. MEANWHILE
WINDS WILL INCREASE ACROSS THE HIGHER TERRAIN OVERNIGHT AS CROSS-
BARRIER FLOW INCREASES TO 35-40 KTS LATE TONIGHT. THUS MAY SEE SOME
GUSTS FROM 50-60 MPH ACROSS PORTIONS OF THE MTNS AND NRN FOOTHILLS.
LONG TERM /THURSDAY THROUGH TUESDAY/
ISSUED AT 243 AM MDT WED OCT 23 2024
WE'LL START THURSDAY WITH A FAIRLY STRONG SHORTWAVE TRACKING JUST
TO OUR NORTH. THE FLOW ALOFT SHOULD INCREASE QUITE A BIT ON
THURSDAY, AND GUSTY WINDS WILL LIKELY DEVELOP ACROSS MOST OF THE
FORECAST AREA AS WIDESPREAD SUBSIDENCE ENTERS IN THE WAKE OF THE
PASSING SHORTWAVE. HIGH RESOLUTION GUIDANCE HINTS AT SOME MOUNTAIN
WAVE AMPLIFICATION THURSDAY MORNING AS THE STABLE LAYER SINKS,
THOUGH THIS WOULD BE BRIEF BEFORE TRANSITIONING TO THE GRADIENT
WINDS. MEANWHILE, A COLD FRONT IS STILL EXPECTED TO TRACK THROUGH
THE PLAINS DURING THE DAY, WITH GUIDANCE PERHAPS A HAIR QUICKER
WITH THE ARRIVAL OF (SLIGHTLY) COOLER TEMPERATURES BEHIND THE
FRONT. THE EARLIER FRONTAL PASSAGE WOULD LIKELY LIMIT THE EXTENT
OF CRITICAL FIRE WEATHER CONDITIONS... BUT TEMPERATURES WILL STILL
BE ABOVE NORMAL, AND THE POST-FRONTAL AIRMASS IS STILL QUITE
DRY... MEANING THAT WIDESPREAD ELEVATED TO NEAR CRITICAL
CONDITIONS ARE STILL EXPECTED THURSDAY AFTERNOON. DIDN'T FEEL
CONFIDENT ENOUGH FOR ANY FIRE WX HIGHLIGHTS AT THIS TIME, AND
WE'LL SEE IF THE DAY SHIFT HAS MORE CONFIDENCE THAN I DO.
FRIDAY SHOULD BE ON THE COOLER SIDE (THOUGH STILL ABOVE NORMAL
FOR THE METRO), WITH QUIET WEATHER. A WARM AIR ADVECTION REGIME
GRADUALLY DEVELOPS DURING THE DAY, AS A RIDGE BEGINS TO QUICKLY
BUILD TO THE SOUTHWEST OF THE FORECAST AREA. MUCH WARMER
TEMPERATURES ARE FORECAST BY THIS WEEKEND AS THE RIDGE EXPANDS AND
SOUTHWESTERLY FLOW ALOFT INCREASES. SATURDAY SHOULD SEE HIGHS
RETURN TO THE 70S ACROSS THE LOWER ELEVATIONS, WITH UPPER 70S
LIKELY BY SUNDAY. IT WOULDN'T BE SURPRISING IF A COUPLE OF SITES
ENDED UP IN THE LOW 80S IN THIS TYPE OF PATTERN, WHICH IS
SUPPORTED BY A HANDFUL OF ENSEMBLE MEMBERS. WELL ABOVE NORMAL
TEMPERATURES MAY LINGER INTO MONDAY AS WELL.
AS WE GET INTO NEXT WEEK, GUIDANCE CONTINUES TO SUGGEST A RATHER
SIGNIFICANT PATTERN CHANGE FOR THE REGION. DETERMINISTIC AND
ENSEMBLE GUIDANCE SHOWS A BROAD, STRONG TROUGH AXIS PUSHING INTO
THE AREA BY EARLY/MID WEEK, WHICH WOULD USHER IN MUCH COOLER
TEMPERATURES ACROSS THE FORECAST AREA. WHILE THE SPECIFICS CAN'T
BE WORKED OUT JUST YET, A LOOK AT WPC'S CLUSTER ANALYSIS SHOWS
THAT THE MAIN UNCERTAINTY IN THIS PERIOD COMES FROM THE
AMPLITUDE/TIMING OF THE TROUGH, RATHER THAN THE EXISTENCE OF THE
TROUGH ITSELF - LEADING TO A RELATIVELY HIGH CONFIDENCE FORECAST
OF NEAR/BELOW NORMAL TEMPERATURES TUESDAY AND BEYOND. ALTHOUGH
WE'RE A FEW DAYS AWAY FROM GETTING A GOOD HANDLE ON PRECIPITATION
POTENTIAL, IT'S WORTH NOTING THAT TONIGHT'S ECMWF ENSEMBLE HAS
>50% PROBABILITIES OF ACCUMULATING SNOW ACROSS THE METRO BY THE
END OF THE FORECAST PERIOD - SIGNALING THE BEST CHANCE OF WINTRY
WEATHER FOR THE DENVER METRO SO FAR THIS SEASON.
AVIATION /12Z TAFS THROUGH 12Z THURSDAY/
ISSUED AT 326 AM MDT WED OCT 23 2024
WINDS WERE LIGHT WSW EARLY THIS MORNING AND SHOULD REMAIN THAT
GENERAL DIRECTION THRU 16Z. WINDS WILL GRADUALLY BECOME MORE SE
BY 17Z AND CONTINUE THIS AFTN. BY EARLY THIS EVENING WINDS WILL
BECOME MORE SSW AND REMAIN THAT GENERAL DIRECTION OVERNIGHT.
WILL KEEP VFR CONDITIONS IN THE 12Z TAF AS ANY THREAT FOR STRATUS
AROUND SUNRISE THIS MORNING LOOKS VERY LOW AT THIS TIME.
BOU WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...RPK
LONG TERM...HIRIS
AVIATION...RPK
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page