129
FXUS65 KBOU 060827
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
227 AM MDT TUE MAY 6 2025
KEY MESSAGES
- SPRING STORM FINALLY ARRIVES IN EARNEST TODAY, BUT LATEST TRENDS
ARE FOR LESS PRECIPITATION. HEAVY, WET SNOW STILL EXPECTED IN
THE FRONT RANGE MOUNTAINS AND HIGHER FOOTHILLS.
- WARMER WEATHER MOVES INTO THE FORECAST AREA ON THURSDAY AND
CONTINUES INTO THE WEEKEND. STILL A FEW LATE DAY SHOWERS AND
STORMS MOST DAYS.
UPDATE
ISSUED AT 226 AM MDT TUE MAY 6 2025
SATELLITE SHOWS A WELL DEFINED UPPER LOW SPINNING ACROSS CENTRAL
NEW MEXICO, AND A HUGE SWATH OF RAIN AND CONVECTION EXTENDING
AROUND THE NORTHERN AND EASTERN PERIPHERY INTO MUCH OF TEXAS. AS
DISCUSSED A BIT LAST NIGHT, IT APPEARS THE LARGE AMOUNT OF LATENT
HEAT RELEASE IN TEXAS MEANS THE UPPER LOW WILL BE TAKING A LITTLE
FARTHER SOUTH TRACK. THIS MEANS WE'LL BE SEEING LESS PRECIPITATION
WITH A WEAKER UPSLOPE COMPONENT (NOW CLOSER TO 20 KTS) AND ALSO
SOME MID LEVEL DRYING COMING IN THIS EVENING FROM THE EAST.
FOR THIS MORNING, RAIN IS STILL EXPECTED TO DEVELOP AND BECOME
WIDESPREAD AS WE STILL TURN OUR WINDS FROM SOUTHERLY TO EASTERLY
THROUGH A VERY DEEP COLUMN. MOISTURE IS MORE THAN PLENTIFUL, WITH
DEWPOINTS IN THE LOWER TO MID 40S ACROSS THE PLAINS, SO ANY SORT
OF UPSLOPE SHOULD INITIATE THE HIGHER COVERAGE OF RAIN. THAT WILL
ALSO GET THE SNOW MACHINE GOING FOR THE FRONT RANGE MOUNTAINS,
WITH STRONG IVT, MODERATE UPSLOPE, AND NEARLY NEUTRAL LAPSE RATES.
SNOW LEVELS ARE STARTING OUT FAIRLY HIGH, AROUND 9,000 FEET PER
CURRENT OBSERVATIONS. HOWEVER, WITH THE PRECIPITATION RATES
INCREASING AND COLD CORE OF THE LOW GETTING A LITTLE CLOSER WE
SHOULD SEE THOSE DROP TO AROUND 8000-8500 FEET ON THIS SIDE OF THE
FRONT RANGE BY AFTERNOON. A LITTLE FURTHER DROP OF ANOTHER 500
FEET OR SO IS THEN ANTICIPATED THIS EVENING. THAT MEANS SOME
SLUSHY TRAVEL POSSIBLE IN THE HIGHER FOOTHILLS TONIGHT. WE THINK
THE BULK OF THE IMPACTS WOULD STAY ABOVE 8,000-8,500 FEET, WHERE
MORE SIGNIFICANT TOTALS ARE STILL ANTICIPATED. THE DROP IN QPF
FORECASTS IS CONCERNING TO TOTAL ACCUMULATIONS, AS LIGHTER
PRECIPITATION RATES WOULD HAVE A COMPOUNDING EFFECT ON
ACCUMULATIONS THROUGH BOTH SNOWFALL RATES AND LESS DIABATIC
COOLING. THE TRENDS ARE CERTAINLY NOT THE FRIEND OF THE SNOW
LOVERS, OR THOSE WANTING A WIDESPREAD HEAVY RAINFALL EVENT IN
LOWER ELEVATIONS. IN FACT, IT NOW APPEARS MOST OF THE I-25
CORRIDOR WILL STAY UNDER 1" FOR RAINFALL, AND 0.5" OR LESS FOR
EAST OF I-25 AND AMOUNTS ALSO TAPERING OFF MORE QUICKLY TO THE
EAST. THAT WOULD BE DUE TO THAT MID LEVEL DRY INTRUSION MENTIONED
BEFORE, AND THE MAIN SYNOPTIC ENERGY STAYING JUST SOUTH OF OUR
FORECAST AREA INTO SOUTHEAST COLORADO AND THE SOUTHERN HIGH
PLAINS.
GIVEN THE FARTHER SOUTH TRACK, PRECIPITATION INTENSITY IS EXPECTED
TO DECREASE THIS EVENING ALREADY, BUT STILL SOME UPSLOPE TO KEEP
LIGHTER RAIN/SNOW FALLING THROUGH THE NIGHT, ESPECIALLY IN THE
UPSLOPE FAVORED AREAS. A MARKED DECREASE IS STILL EXPECTED BY
WEDNESDAY MORNING AS UPSLOPE WEAKENS AND ANY SYNOPTIC SCALE
SUPPORT CONTINUES TO SHIFT AWAY FROM THE AREA. WEDNESDAY AFTERNOON
WILL STILL SEE SOME SHOWERS AROUND, GIVEN PLENTY OF RESIDUAL
MOISTURE, AND LIMITED DAYTIME HEATING AND DESTABILIZATION.
FINALLY, A COUPLE RUMBLES OF THUNDER WILL BE POSSIBLE BOTH DAYS.
WITH A LITTLE MORE HEATING TODAY ON THE PLAINS, THERE'S A VERY
SMALL 5% CHANCE OF SOMETHING TRYING TO SPIN UP INTO A SHALLOW
UPDRAFT.
FOR THE REST OF THE PERIOD, THE FORECAST IS CONSISTENT WITH A
WARMING TREND AND SCATTERED SHOWERS AND A FEW THUNDERSTORMS EACH
DAY - HIGHEST COVERAGE OVER THE MOUNTAINS.
PREVIOUS DISCUSSION/THROUGH MONDAY/
ISSUED AT 232 PM MDT MON MAY 5 2025
MODELS SHOW AN UPPER LEVEL LOW TO MOVE SLOWLY EASTWARD INTO THE
TEXAS PANHANDLE BY 12Z WEDNESDAY MORNING. MODELS ALSO SHOW AN
UPPER CIRCULATION BACK TO THE SOUTHWEST OF COLORADO OVER SOUTHERN
NEVADA AT 12Z WEDNESDAY MORNING. THIS SLOW MOVING SYSTEM WILL
PROVIDE ENOUGH MOISTURE AND SYNOPTIC ENERGY TO BRING A DECENT
PRECIPITATION EVENT TO THE CWA TUESDAY INTO WEDNESDAY MORNING. THE
VARIOUS MODELS SHOW THAT 1.0-3.0 INCHES OF LIQUID COULD FALL OVER
THE SOUTHERN CWA ON UP THROUGH THE MOUNTAINS, FOOTHILLS AND
IMMEDIATE PLAINS.
THERE WILL BE WINTER WEATHER DRIVING IMPACTS WITH THE STORMS,
ESPECIALLY FOR THE MOUNTAIN ZONES AND IN THE HIGHER FOOTHILLS,
ESPECIALLY TUESDAY NIGHT.
THE CURRENT WINTER STORM WATCH WILL BE UPGRADED TO A WINTER STORM
WARNING FROM 12Z TUESDAY THROUGH 12Z WEDNESDAY FOR THE HIGH
MOUNTAIN ZONES; 33 AND 34. WE WILL ALSO GO WITH WINTER WEATHER
ADVISORIES FOR PARK COUNTY AND THE FRONT RANGE FOOTHILLS; 35, 36
AND 37. RAIN WILL FALL OVER THE PLAINS AND PALMER RIDGE TUESDAY
AND TUESDAY NIGHT. HIGH TEMPERATURES WILL BE WELL BELOW SEASONAL
NORMALS ON TUESDAY WITH MID 40S TO MID 50S OVER THE PLAINS.
PRECIPITATION SHOULD LINGER THROUGH WEDNESDAY AS THIS SYSTEM
SLOWLY TRAVELS EAST. AREAS OF LIGHT TO MODERATE RAIN ARE EXPECTED
WEDNESDAY MORNING BEFORE DECREASING IN THE AFTERNOON AND TAPERING
OFF BY THE EVENING. THERE COULD BE ADDITIONAL QPF AMOUNTS OF
0.1-0.3" ACROSS THE PLAINS, WITH MINIMAL ADDITIONAL SNOW
ACCUMULATIONS FOR ELEVATIONS ABOVE 8,500 FT. THE THREAT FOR ANY
SEVERE WEATHER IS LOW AS LAPSE RATES LOOK UNIMPRESSIVE ON THE
PLAINS. HOWEVER, WITH MUCAPE VALUES UP TO A COUPLE HUNDRED J/KG AT
TIMES IN THE EARLY AFTERNOON, CAN'T RULE OUT A RUMBLE OF THUNDER.
TEMPERATURES WILL BE SLIGHTLY WARMER THAN TUESDAY, WITH HIGHS
REACHING UP TO THE MID 50S AND MID 60S ACROSS THE PLAINS.
GUIDANCE IS IN GOOD AGREEMENT OF THE UPPER LEVEL LOW EVENTUALLY
MAKING IT TO KANSAS AND WEAKENING BY WEDNESDAY EVENING. WITH FLOW
ALOFT DECREASING AND TURNING MORE NORTHEASTERLY, OUR DEEP MOISTURE
SUPPLY WILL BE CUT OFF FROM THE SOUTH AND THUS DECREASE OUR
PRECIPITATION CHANCES FOR THE MAJORITY OF THE REGION BY THURSDAY.
HOWEVER, WITH RESIDUAL MOISTURE FROM THE SYSTEM AND A WEAK PIECE
OF UPPER LEVEL ENERGY PASSING THROUGH, THERE COULD BE SOME
CONVECTIVE SHOWERS ALONG THE FRONT RANGE MOUNTAINS IN THE
AFTERNOON. PRECIPITATION SHOULD BE CONFINED TO THE HIGH COUNTRY,
BUT THERE IS A SMALL CHANCE (20%) IT COULD SPILL INTO THE LOWER
FOOTHILLS.
FRIDAY AND THROUGH THE WEEKEND, ENSEMBLE MODELS HAVE HONED IN ON
AN UPPER LEVEL RIDGE BUILDING OVER THE WESTERN UNITED STATES.
ABOVE NORMAL TEMPERATURES ARE LIKELY, WITH HIGH TEMPERATURES IN
THE LOW 80S EXPECTED BY MONDAY. ASIDE FROM DIURNAL CONVECTIVE
SHOWERS IN THE HIGH COUNTRY, MOST OF THE AREA SHOULD REMAIN DRY.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 1134 PM MDT MON MAY 5 2025
AREAS OF STRATUS WITH MVFR CEILINGS WILL LIKELY BE IN/OUT THROUGH
10Z DUE TO VARIABILITY ASSOCIATED WITH THE DOWNSLOPE SOUTHEAST
FLOW, BUT THEN LOW LEVEL WINDS TURN MORE EASTERLY OR EVEN
NORTHERLY 10Z-12Z, AND THAT SHOULD ALLOW LOWER CEILINGS DOWN INTO
THE 600-1500 FT RANGE TO DEVELOP AND BECOME MORE WIDESPREAD. WE'LL
ALSO SEE RAIN DEVELOP 12Z-16Z, WITH A STEADY RAIN BY 16Z.
CEILINGS SHOULD GENERALLY REMAIN AT OR LESS THAN 1000 FEET WITH
VISIBILITY OF 3-5SM IN LIGHT RAIN AND FOG GIVEN EASTERLY UPSLOPE
FLOW. IT NOW APPEARS PRECIPITATION TURNS MORE SHOWERY AFTER
01Z-02Z WITH A LITTLE DRY INTRUSION ALOFT, BUT IFR WITH LOW
CEILINGS, LIGHT FOG, AND OFF/ON LIGHT RAIN SHOULD STICK AROUND
THROUGH THE REMAINDER OF THE TAF PERIOD (12Z WEDNESDAY).
BOU WATCHES/WARNINGS/ADVISORIES
WINTER STORM WARNING FROM 6 AM THIS MORNING TO 6 AM MDT
WEDNESDAY FOR COZ033-034.
WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM MDT WEDNESDAY
FOR COZ035-036.
WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 6 AM MDT
WEDNESDAY FOR COZ037.
UPDATE...BARJENBRUCH
PREVIOUS...RJK/IDEKER
AVIATION...BARJENBRUCH
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