288
FXUS65 KBOU 191155
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
555 AM MDT FRI APR 19 2024
KEY MESSAGES
- SPRINGTIME SNOW IN THE ROCKIES, WITH ACCUMULATIONS EXPECTED IN
MOST LOCATIONS TONIGHT THROUGH SATURDAY MORNING. PATCHY
DRIZZLE/FREEZING DRIZZLE TO START THE DAY
- SLICK AND HAZARDOUS TRAVEL IN THE FOOTHILLS, AND POSSIBLY ONTO
THE ADJACENT PLAINS INTO SATURDAY MORNING
- COLD THROUGH SATURDAY, THEN DRIER AND WARMER FOR SUNDAY THROUGH
MUCH OF NEXT WEEK.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 1257 AM MDT FRI APR 19 2024
PLENTY OF LOW CLOUD COVER IN NORTHEAST COLORADO THIS MORNING. RADAR
SHOWS A BIT OF A DIFFERENT PICTURE THAN IT DID LATE LAST EVENING
WITH A FAIRLY ORGANIZED BAND OF SNOW EXTENDING FROM THE FOOTHILLS OF
BOULDER COUNTY EASTWARD ONTO THE PLAINS. THERE ISN'T HIGH CERTAINTY
ON HOW LONG THIS BAND REMAINS ORGANIZED, BUT MOST MODEL GUIDANCE
DOESN'T KEEP IT AROUND TOO LONG THIS MORNING. A FEW SHOWERS WILL BE
POSSIBLE FOR THE REMAINDER OF THIS MORNING ACROSS THE EAST SLOPE
AND ADJACENT PLAINS. TEMPERATURES IN THE URBAN CORRIDOR ARE A
LITTLE ABOVE FREEZING. IF IT WERE A TAD COLDER AT THE SURFACE,
FREEZING DRIZZLE WOULD BE MORE OF A THREAT THIS MORNING GIVEN THE
LOW STRATUS. WITH LIGHT SNOW IN PARTS OF THE FOOTHILLS AND COOLER
TEMPERATURES OVERALL, THERE MAY BE SOME SLICK SPOTS OUT THERE THIS
MORNING.
PLENTY OF SMALL YET CHALLENGING ELEMENTS IN THE FORECAST TODAY
AND TONIGHT. COLORADO WILL BE UNDER ZONAL FLOW ALOFT WITH A QUICK
SHORTWAVE TROUGH MOVING ACROSS INTO SATURDAY. THIS MORNING, THERE
IS A GOOD AMOUNT OF MOISTURE IN PLACE WITH THE LOW STRATUS TO
PROVE IT. THE FIRST QUESTION WILL BE IF AND HOW LONG THESE LOW
CLOUDS STICK AROUND. FOR MOST AREAS, IT IS BECOMING MORE LIKELY
THAT THE STRATUS STICKS AROUND TODAY WITH SOME SUBTLE THINNING OR
RISING IN THE AFTERNOON. AREAS SOUTH OF I-70 HAVE A BETTER CHANCE
AT SOME BREAKS IN THE DECK. WITH THAT SAID, CLOUD COVER AND A
COOLER AIRMASS WILL KEEP HIGHS COOL TODAY. HAD TO DO SOME MANUAL
ADJUSTING TO THE HIGHS AS MOST GUIDANCE WAS TOO WARM. HIGHS WILL
LIKELY REMAIN IN THE LOW 40S ACROSS THE PLAINS.
LATE THIS AFTERNOON THROUGH SATURDAY MORNING WILL BE THE MOST
"WEATHER-ACTIVE" TIMEFRAME. AS THE NEXT WAVE APPROACHES, BETTER
ASCENT AND MOISTURE MOVES INTO THE AREA. SNOW SHOWERS DEVELOP IN THE
MOUNTAINS THIS AFTERNOON. A FRONT WILL MOVE ACROSS THE PLAINS IN THE
LATE AFTERNOON-EARLY EVENING TIMEFRAME BRINGING A PUSH OF NE UPSLOPE
WINDS AND ADDITIONAL COLD AIR ADVECTION. THIS WILL HELP DEVELOP
SHOWERS ACROSS THE LOWER ELEVATIONS. THIS WILL START AS RAIN.
EARLY EVENING, AS TEMPERATURES COOL, SNOW WILL BEGIN TO MIX IN AND
CHANGE TO SNOW. HAD TO WRESTLE A BIT WITH THE SNOW LEVELS TO
PAINT THE RIGHT PICTURE. THERE IS A LOW CHANCE FOR SOME FREEZING
DRIZZLE EARLY PM ON THE PLAINS. MOISTURE SHOULD BE DEEP ENOUGH TO
COMBAT THIS HOWEVER.
THE JET WILL PLAY A ROLE IN THIS EVENT AS IT WILL SUPPORT MORE
ORGANIZED BANDING ACROSS THE EASTERN SLOPE MOUNTAINS AND PLAINS
FRIDAY NIGHT INTO SATURDAY. HOWEVER, THE DOWNFALL OF BANDS IS THE
LOWER CONFIDENCE IN EXACT PLACEMENT AND MORE LOCALIZED TOTALS.
THIS ISN'T LOOKING LIKE A HIGH-IMPACT EVENT. CAN'T RULE OUT A FEW
LOCALIZED BANDS WITH MORE MODERATE RATES (0.5-1"/HOUR). GENERALLY,
BANDS WILL MOVE NORTHWARD ACROSS THE I-25 CORRIDOR, AND EAST
SLOPE OVERNIGHT WHILE ALSO SPREADING EASTWARD ONTO THE PLAINS.
ENSEMBLE MEANS ARE STILL CONSISTENT WITH MODERATE TO HIGH PROBABILITIES
40-80% FOR 1-3" FOR THE ADJACENT PLAINS. AS YOU GO FURTHER
EASTWARD, CONFIDENCE DECREASES IN EXACT AMOUNTS AND THIS IS DUE TO
THE LOCALIZED NATURE OF THE BANDING. THE EAST SLOPES OF THE FRONT
RANGE AND THE FOOTHILLS WILL BE MOST FAVORED WITH AMOUNTS IN THE
4-10 INCH RANGE. AS A RESULT, A WINTER WEATHER ADVISORY HAS BEEN
ISSUED FOR THE MENTIONED AREAS ALONG THE FRONT RANGE
MOUNTAINS/FOOTHILLS.
LONG TERM /SATURDAY THROUGH THURSDAY/
ISSUED AT 230 AM MDT FRI APR 19 2024
SNOW WILL BE ONGOING SATURDAY MORNING OVER MUCH OF THE FRONT
RANGE MOUNTAINS, FOOTHILLS, AND PLAINS. HOWEVER, THE BEST LIFT IN
THE FORM OF THE RIGHT ENTRANCE REGION OF THE UPPER JET, QG, AND
MID LEVEL FRONTOGENESIS WILL BE WEAKENING. THUS, SNOW WILL START
TO TAPER OFF ONCE WE HIT MID MORNING WITH A FURTHER DECREASE IN
MOST AREAS THROUGH THE AFTERNOON. ANOTHER INCH OR SO OF
ACCUMULATION IS EXPECTED BEFORE TAPERING OFF IN THE MID TO LATE
MORNING HOURS. THERE WILL BE SOME CONVECTIVE REDEVELOPMENT IN AND
NEAR THE MOUNTAINS IN THE AFTERNOON DUE TO MID LEVEL INSTABILITY,
BUT ADDITIONAL ACCUMULATION WITH THOSE WILL BE MINIMIZED BY
DAYTIME "HEATING". HEATING IS A LOOSE TERM, AS HIGH TEMPERATURES
EVEN ON THE PLAINS WILL BE STRUGGLING TO REACH THE LOWER 40S
GIVEN SOME FRESH SNOW ON THE GROUND, PERSISTENT LOW CLOUDS, AND
SHALLOW UPSLOPE.
NOW, IF YOU'RE LOOKING FOR NICE WEATHER, YOU DON'T HAVE TO LOOK
ANY FURTHER THAN SUNDAY. WESTERLY FLOW DEVELOPS WHICH WILL LEAD TO
WARM ADVECTION, A RETURN OF SUNSHINE, AND DOWNSLOPE WARMING.
THUS, WE EXPECT HIGH TEMPERATURES TO PUSH BACK INTO THE MID TO
UPPER 60S. FURTHER WARMING IS LIKELY TO OCCUR MONDAY WITH GOOD
ENSEMBLE AGREEMENT THAT WE'LL REACH THE 70S ACROSS THE PLAINS,
ALTHOUGH A COLD FRONT POTENTIALLY REACHES US EARLIER SHAVING A FEW
DEGREES OFF THOSE NUMBERS.
THAT LATE MONDAY COOLING WILL LAST INTO TUESDAY, BUT THEN WARMER
TEMPERATURES WILL RE-ESTABLISH THEMSELVES FOR WEDNESDAY INTO
THURSDAY IN ADVANCE OF THE NEXT STORM SYSTEM. THAT STORM
SYSTEM'S ARRIVAL IS EXPECTED TO BRING A RETURN OF UNSETTLED
WEATHER TOWARD FRIDAY WITH SCATTERED SHOWERS AND STORMS, AND SOME
MOUNTAIN SNOWFALL ALONG WITH COOLER TEMPERATURES.
AVIATION /12Z TAFS THROUGH 12Z SATURDAY/
ISSUED AT 555 AM MDT FRI APR 19 2024
CEILING AND WEATHER IMPACTS ARE EXPECTED TO CONTINUE THROUGH THE
TAF PERIOD.
A BATCH OF LIGHT SNOW SHOWERS HAS MADE IT ACROSS BJC AND DEN
WITHIN THE LAST HOUR OR SO THIS MORNING. A FEW VCSH ARE POSSIBLE
THIS MORNING, BUT WILL BE A LOW CHANCE. EXPECT SMALL IMPROVEMENTS
IN THE CEILINGS THIS MORNING INTO THE EARLY AFTERNOON. THIS WILL
PUT THEM IN THE UPPER MVFR TO LOW VFR CATEGORY (AT BEST). A DENVER
CYCLONE WIND PATTERN WILL DOMINATE THE WIND DIRECTION TODAY WITH
WINDS TURNING TO THE NORTHWEST THIS MORNING THEN MORE NORTHERLY
FOR THE AFTERNOON.
A FRONT MOVES ACROSS COLORADO IN THE LATE AFTERNOON-EARLY EVENING
TIMEFRAME (20-00Z) FOLLOWED BY A PUSH OF NORTHEAST WINDS. SHOWERS
DEVELOP AROUND THE TERMINALS MID TO LATE AFTERNOON WITH LOWERING
CEILINGS. EARLY EVENING SNOW WILL LIKELY BEGIN TO MIX IN AND
CHANGEOVER. WITH LIGHT SNOW, CONDITIONS DROP BACK INTO LOW MVFR
TO IFR WITH LOWER VISIBLITIES AND CEILINGS. BRIEFS DROPS TO 1/2SM
ARE POSSIBLE IN SOME SNOW BANDS. THIS WILL CONTINUE OVERNIGHT
WITH LINGERING SHOWERS SATURDAY MORNING.
BOU WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 9 AM MDT
SATURDAY FOR COZ033>036.
SHORT TERM...MENSCH
LONG TERM...BARJENBRUCH
AVIATION...MENSCH
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