257
FXUS65 KBOU 051831
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
1231 PM MDT TUE MAY 5 2026
KEY MESSAGES
- A SIGNIFICANT SPRING SNOWSTORM IS DEVELOPING ACROSS THE COLORADO
FRONT RANGE, AND WILL PRODUCE HEAVY SNOW IN OUR NORTHERN
MOUNTAINS AND FOOTHILLS TODAY.
- SCATTERED RAIN AND SNOW SHOWERS ACROSS THE LOWER ELEVATIONS WILL
FULLY TRANSITION TO SNOW BY THIS EVENING, WITH ACCUMULATIONS
OCCURRING OVERNIGHT INTO WEDNESDAY MORNING, POTENTIALLY
IMPACTING THE MORNING COMMUTE. SNOW WILL TAPER OFF NORTH TO
SOUTH WEDNESDAY AFTERNOON/EVENING.
- THE HEAVY, WET NATURE OF THE SNOW WILL LEAD TO DAMAGE TO TREE
LIMBS AND POWER LINES. SIGNIFICANT TRAVEL IMPACTS CAN BE
EXPECTED FOR THE HIGHER ELEVATIONS, WITH MORE UNCERTAINTY IN THE
EXTENT OF THESE ACROSS THE LOWER ELEVATIONS ON WEDNESDAY.
- RETURN TO A WARMER PATTERN LIKELY BY THE LATTER HALF OF THE WEEK
WITH A CHANCE OF SNOW SHOWERS IN THE MOUNTAINS.
DISCUSSION /THROUGH MONDAY/
ISSUED AT 100 AM MDT TUE MAY 5 2026
THINGS APPEAR TO BE COMING TOGETHER FOR A LATE SEASON SNOW EVENT
ACROSS MUCH OF THE AREA. AN UPPER LEVEL TROUGH WILL MOVE SSE FROM
THE NRN ROCKIES ACROSS THE AREA FROM TUE AFTN THRU WED. BEST QG
ASCENT WITH THIS FEATURE WILL BE TUE NIGHT THRU MIDDAY WED. CROSS-
SECTIONS SHOW PLENTY OF MOISTURE WITH THIS SYSTEM ALONG WITH
FAVORABLE LAPSE RATES. LOW LEVEL FLOW WILL GENERALLY BE EASTERLY
THRU EARLY TUE EVENING AND THEN SHIFT TO THE NORTHEAST AFTER
MIDNIGHT, AS A SECONDARY COLD FRONT MOVES ACROSS, WHICH ENHANCES
LOW LEVEL UPSLOPE COMPONENT THRU MIDDAY WED. IN ADDITION, ANALYSIS
OF CROSS-SECTIONS SHOW POTENTIAL FOR JET ENHANCED HEAVIER PCPN AS
WELL ACROSS PORTIONS OF THE AREA. PRECIP COULD CHANGE TO SNOW BY
MIDDAY ALONG THE I-25 CORRIDOR WITH A MIX ACROSS THE PLAINS. WITH
A HIGH SUN ANGLE BELIEVE ANY SNOW THAT FALLS AT LOWER ELEVATIONS
WILL GENERALLY MELT THRU THE AFTN. HOWEVER, ACROSS THE MTNS AND
FOOTHILLS EXPECT PERIODS OF HEAVIER SNOW ESPECIALLY NORTH OF I-70
THRU THE AFTN.
BY TUE EVENING, SNOW WILL OCCUR ACROSS THE HIGHER TERRAIN AND ALONG
THE I-25 CORRIDOR AND ADJACENT PLAINS. AS THE SECONDARY COLD FRONT
MOVES ACROSS SHOULD SEE HEAVY SNOW DEVELOP OVERNIGHT WHICH WILL
CONTINUE THRU WED MORNING OVER THE I-25 CORRIDOR AND PORTIONS OF THE
PLAINS. LATEST DATA FROM OPERATIONAL AND ENSEMBLE BASED MODELS
CONTINUE TO SHOW SEVERAL INCHES OF HEAVY WET SNOW AT LOWER
ELEVATIONS THRU MIDDAY WED. THUS HAVE UPGRADED PREVIOUS WATCHES
TO WARNINGS AND EXPANDED THE WINTER WEATHER ADVISORY FURTHER EAST
ACROSS THE PLAINS. THERE COULD EVENTUALLY BE WARNING CRITERIA SNOW
ACROSS PORTIONS OF THE ADJACENT PLAINS BUT CONFIDENCE ISN'T HIGH
ENOUGH AT THIS POINT FOR A WARNING.
QPF AMOUNTS VARY FROM 1.0" TO 1.5" OF WATER ACROSS THE PLAINS WITH
1.5" TO 2.5" OF WATER ACROSS PORTIONS OF THE MTNS AND NORTHERN
FOOTHILLS. AS FOR SNOW AMOUNTS, MTN AREAS NORTH OF I-70 MAY SEE
18 TO 36 INCHES WITH UP TO 24 INCHES IN THE NRN FOOTHILLS. ALONG
AND SOUTH OF I-70 WILL SEE LOWER SNOW TOTALS. ACROSS THE I-25
CORRIDOR, FOR NOW HAVE KEPT AMOUNTS IN THE 4 TO 8 INCH RANGE WITH
LOCALLY UP TO 12 INCHES CLOSER TO THE FOOTHILLS AND OVER THE
PALMER DIVIDE. OVER THE PLAINS HAVE KEPT AMOUNTS MAINLY IN THE 3
TO 6 INCH RANGE. KEEP IN MIND, SOME OF THE HIGHER RES GUIDANCE HAS
HIGHER AMOUNTS ACROSS THE I-25 CORRIDOR AND PLAINS. THUS MAY HAVE
TO INCREASE AMOUNTS IF ADDITIONAL DATA OVERNIGHT CONTINUES TO
TREND TOWARDS THE HIGHER AMOUNTS.
OVERALL, SNOW SHOULD GRADUALLY DECREASE FROM NORTH TO SOUTH BY WED
AFTN WITH SNOW ENDING BY EARLY WED EVENING ACROSS SOUTHERN AREAS OF
THE CWA. MEANWHILE, OVERNIGHT LOWS INTO THU MORNING WILL DROP
WELL BELOW FREEZING ACROSS MOST OF THE PLAINS.
LOOKING AHEAD TO THU AND THU NIGHT, A WEAK DISTURBANCE EMBEDDED IN
NW FLOW ALOFT MAY BRING A CHC OF SNOW TO THE MTNS THU NIGHT WITH A
SLIGHT CHC OF SHOWERS ACROSS THE PLAINS.
FOR FRI AND SAT, NW FLOW ALOFT WILL REMAIN OVER THE AREA. THE ECMWF
HAS ANOTHER DISTURBANCE MOVING ACROSS ON SAT WHILE THE GFS DOESN'T.
LATEST BLENDED SOLUTION IS ALIGNED MORE WITH THE ECMWF SO WILL KEEP
IN A CHC OF SHOWERS ACROSS THE AREA.
TEMPS WILL BEGIN TO WARM ON THU WITH ABOVE NORMAL READINGS EXPECTED
FRI AND SAT ACROSS THE AREA.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1224 PM MDT TUE MAY 5 2026
CROSS SECTIONS AND SOUNDINGS POINT TO KEEPING CEILINGS IN THE
BKN-OVC010-025 RANGE THROUGH THE AFTERNOON. WILL GO WITH VISIBILITIES
IN THE 3-5SM RANGE DUE TO BR AND SOMETIMES -RA OR -SHRA. LATEST
TIMING FOR ALL SNOW AT DIA SHOULD BE ABOUT 01Z. FROM THEN ON,
WILL KEEP CEILINGS BELOW OVC006 AND VISIBILITIES OF 1/2SM WITH SN
FG OR FZFG. LIGHT EAST AND NORTHEASTERLY WINDS ARE EXPECTED AT DIA
THROUGH AROUND MID EVENING. MORE NORTHERLY DIRECTIONS ARE
EXPECTED FROM MID EVENING CONTINUING OVERNIGHT INTO WEDNESDAY.
SPEEDS LOOK TO BE UNDER 10 KNOTS THROUGH MUCH OF TONIGHT WITH A
SLIGHT INCREASE AROUND 12Z WEDNESDAY MORNING. THERE DOESN'T LOOK
TO BE ANY IMPROVEMENT UNTIL LATE WEDNESDAY MORNING.
BOU WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 3 PM MDT
WEDNESDAY FOR COZ030-032-037-042>046-049.
WINTER WEATHER ADVISORY UNTIL NOON MDT WEDNESDAY FOR COZ031.
WINTER STORM WARNING UNTIL 3 PM MDT WEDNESDAY FOR COZ033>036.
WINTER STORM WARNING FROM 8 PM THIS EVENING TO 3 PM MDT
WEDNESDAY FOR COZ038>041.
FREEZE WARNING FROM 8 PM WEDNESDAY TO 8 AM MDT THURSDAY FOR
COZ038>051.
DISCUSSION...RPK
AVIATION...66
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