320
FXUS65 KBOU 171743
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
1143 AM MDT WED JUN 17 2026
KEY MESSAGES
- WARM THIS WEEK, WITH HEAT PEAKING WEDNESDAY. PORTIONS OF THE
PLAINS COULD SEE AFTERNOON HIGHS IN THE LOW TO MID 90S.
- ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS POSSIBLE EACH DAY
THIS WEEK, WITH WIDESPREAD CRITICAL FIRE WEATHER CONDITIONS
LIKELY FOR THE MOUNTAINS AND VALLEYS ON WEDNESDAY.
- MORE ACTIVE WEATHER MAY RETURN BY THE WEEKEND INTO EARLY NEXT
WEEK.
DISCUSSION /THROUGH TUESDAY/
ISSUED AT 229 AM MDT WED JUN 17 2026
HOT AND MOSTLY DRY CONDITIONS EXPECTED THROUGH THE WEEKEND AS AN
UPPER LEVEL RIDGE CONTINUES TO DOMINATE THE WEATHER PATTERN. TODAY,
BREEZY WINDS WILL BRING CRITICAL FIRE WEATHER CONDITIONS TO THE
MOUNTAINS AND VALLEYS WHERE A RED FLAG WARNING WILL BE IN EFFECT IN
THE AFTERNOON. NORTHWEST FLOW ALOFT WILL STRENGTHEN, WITH A 45-55 KT
JET OVER COLORADO. THIS WILL ALLOW WINDS TO GUST UP TO 50 MPH ACROSS
THE MOUNTAINS, WITH LOCALIZED HIGHER GUSTS POSSIBLE.
FOR THE LOWER ELEVATIONS, DOWNSLOPING WINDS WILL AID IN
COMPRESSIONAL HEATING AND ALLOW TEMPERATURES TO POSSIBLY REACH UP TO
THE MID-90S BY THE AFTERNOON. WINDS GUSTING UP TO 25-35 MPH (AND
POSSIBLY HIGHER FOR AREAS OFF THE CHEYENNE RIDGE) POSSIBLE
THROUGHOUT THE DAY. HOWEVER, HI-RES GUIDANCE DOES HAVE A WEAK COLD
FRONT MOVING THROUGH THE PLAINS IN THE EARLY MORNING, WHICH WOULD
KEEP WEAKER NORTHEAST WINDS IN PLACE. AS OF RIGHT NOW, MODELS HAVE
THE FRONT WASHING OUT, WITH DOWNSLOPING WINDS RETURNING BY THE
AFTERNOON. HOWEVER, DESPITE MOST MODELS NOT RESOLVING IT, DOWNSLOPE
WINDS USUALLY DO NOT MATERIALIZE AFTER A FRONTAL PASSAGE. IF WE DO
NOT MIX OUT BY THE AFTERNOON, TEMPERATURES WOULD NOT REACH THEIR
FORECASTED HIGHS. FOR THIS REASON, HAVE SLIGHTLY LOWERED MAX
TEMPERATURES FOR THE PLAINS. WE WILL LIKELY NOT REACH HEAT ADVISORY
CRITERIA, HOWEVER GUIDANCE STILL HAS AREAS ALONG THE I-25 CORRIDOR
(INCLUDING THE DENVER METRO) IN A CATEGORY 2 FOR HEAT RISK. THIS
CORRELATES TO A MODERATE RISK FOR THOSE WHO ARE SENSITIVE TO
HEAT. THOSE WHO ARE VULNERABLE TO HEAT SHOULD TAKE NECESSARY
PRECAUTIONS TODAY.
A STRONGER COLD FRONT IS PROGGED TO TREK ACROSS COLORADO WEDNESDAY
EVENING. THIS WILL BRING COOLER TEMPERATURES FOR THURSDAY, WITH
FORECASTED HIGHS IN THE MID-80S FOR THE PLAINS. HOWEVER, THIS MILD
REPRIEVE IN HOT TEMPERATURES WILL BE SHORT LIVED, AS THE UPPER
LEVEL RIDGE IS PROGGED TO SHIFT EAST AND THE AXIS OF THE MID-LEVEL
THERMAL RIDGE SITUATES ITSELF OVER COLORADO. TEMPERATURES WILL
ONCE AGAIN RISE TO THE LOW 90S ACROSS THE PLAINS ON FRIDAY.
FOR THE WEEKEND, ENSEMBLE GUIDANCE HAS THE UPPER LEVEL RIDGE FLATTEN
DUE TO AN INCOMING SHORTWAVE TROUGH. COMPRESSIONAL HEATING ON
SATURDAY COULD ALLOW TEMPERATURES TO REACH TO THE UPPER 90S. CURRENT
ENSEMBLE SOLUTIONS RANGE FROM 91-99 F, WITH A FEW SHOWING 100 F.
ALTHOUGH IT IS IMPORTANT TO NOTE THAT THE 00Z GEFS HAS TRENDED
COOLER. WILL KEEP AN EYE TO SEE IF THAT TREND CONTINUES. WITH THE
ARRIVAL OF THE SHORTWAVE, PRECIPITATION CHANCES INCREASE, MAINLY FOR
THE EASTERN PLAINS. SUNDAY COULD SEE A FEW THUNDERSTORMS, HOWEVER
BEST INSTABILITY LOOKS TO BE JUST EAST OF THE FORECAST AREA.
GUIDANCE LOOKS TO KEEP TEMPERATURES NEAR SEASONAL NORMALS SUNDAY
THROUGH TUESDAY, WITH ADDITIONAL PRECIPITATION CHANCES IN THE
AFTERNOONS.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 1139 AM MDT WED JUN 17 2026
VFR CONDITIONS SHOULD PREVAIL THROUGH THE TAF PERIOD, WITH WINDS
THE MAIN CONCERN THROUGH THURSDAY MORNING.
FAIRLY STRONG COLD FRONT PUSHED THROUGH THE TERMINALS BETWEEN
ABOUT 15-17Z THIS MORNING. EAST/NORTHEAST WINDS REMAIN IN PLACE
ACROSS VIRTUALLY ALL OF THE I-25 CORRIDOR AT THIS POINT, WHICH
VERY FEW DETERMINISTIC MODELS HAD OCCURRING AT ANY TIME TODAY.
HAVE HEDGED ALMOST ENTIRELY ON THE ECMWF/RGEM SOLUTIONS WHICH
MAINTAIN A LIGHT NE COMPONENT THIS AFTERNOON, BEFORE WINDS ARE
REINFORCED BY ANOTHER FRONT THIS EVENING (~02-04Z). WE CAN'T
ENTIRELY RULE OUT THE REDEVELOPMENT OF WNW WINDS ACROSS THE METRO
THIS AFTERNOON... WITH THE BEST CHANCE OF SEEING THAT AT BJC.
TONIGHT'S FRONT WILL STILL BE MOSTLY DRY, BUT THERE COULD BE A BIT
OF MID-LEVEL CLOUD COVER DEVELOPING BY EARLY THURSDAY MORNING.
WINDS THURSDAY AM SHOULD SLOWLY SHIFT BACK TO THE SOUTH OR
SOUTHEAST, WITH A WEAK CYCLONE/SHEAR ZONE DEVELOPING BY THURSDAY
AFTERNOON.
FIRE WEATHER
ISSUED AT 229 AM MDT WED JUN 17 2026
CRITICAL FIRE WEATHER CONDITIONS EXPECTED FOR THE MOUNTAINS AND HIGH
VALLEYS TODAY. WINDS GUSTING UP TO 50 MPH, WITH LOCALIZED STRONGER
GUSTS UP TO 60-65 MPH IS POSSIBLE. WITH DOWNSLOPING WINDS POSSIBLE
FOR THE LOWER ELEVATIONS, THERE COULD BE LOCALIZED ELEVATED FIRE
WEATHER CONDITIONS FOR THE FOOTHILLS AND ADJACENT PLAINS. HOWEVER,
FUELS HAVE BEEN DEEMED NOT CRITICAL, SO NO FIRE WEATHER HIGHLIGHTS
ARE EXPECTED. ANOTHER AREA OF POTENTIAL CONCERN TODAY ARE THE FAR
NORTHEASTERN PLAINS. WINDS OFF THE CHEYENNE RIDGE COULD BRING GUSTS
UP TO 35 MPH. HOWEVER, WITH A COLD FRONT ARRIVING, RH VALUES SHOULD
STAY ABOVE 15%.
ELEVATED FIRE WEATHER CONDITIONS POSSIBLE THURSDAY AND FRIDAY FOR
THE MOUNTAINS AND HIGH VALLEYS DUE TO CONTINUED LOW RH VALUES.
HOWEVER, WINDS SHOULD BE WEAKER, WITH SPEEDS GENERALLY UNDER 25 MPH.
GUSTS OF 30-35 MPH COULD OCCUR, HOWEVER THEY SHOULD BE SHORT IN
DURATION. IF GUIDANCE CHANGES, MAY NEED TO HAVE HIGHLIGHTS OUT.
WITH THE UPPER LEVEL RIDGE FLATTENING ON SATURDAY, CROSS-BARRIER
FLOW IS EXPECTED TO INCREASE, WITH WINDS BECOMING STRONGER AND MORE
WIDESPREAD ACROSS THE MOUNTAINS AND VALLEYS. RELATIVE HUMIDITY
VALUES WILL CONTINUE TO RANGE BETWEEN 11-15% WHICH WILL BRING ABOUT
ANOTHER ROUND OF CRITICAL FIRE WEATHER CONDITIONS.
BOU WATCHES/WARNINGS/ADVISORIES
RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR COZ211>214-217-
218.
DISCUSSION...MAI
AVIATION...HIRIS
FIRE WEATHER...MAI
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