Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 020314
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
914 PM MDT WED APR 1 2015

.UPDATE...
ISSUED AT 914 PM MDT WED APR 1 2015

NO REASON TO CHANGE COURSE AT THIS TIME. THE ANTICIPATED ROUND OF
SHOWERS AND THUNDERSTORMS MOVED ACROSS THE PLAINS EARLIER THIS
EVENING AND IS NOW CROSSING INTO SOUTHWEST NEBRASKA AND NORTHWEST
KANSAS. THE SHOWERS CONTAINED A LOT OF GUSTY WIND BUT ONLY SMALL
AMOUNTS OF RAINFALL...PRIMARILY OVER WASHINGTON AND LINCOLN
COUNTIES. PRECIPITATION WILL TAKE A BREAK ACROSS THE FORECAST AREA
OVERNIGHT AS THE NEXT WEATHER SYSTEM APPROACHES FROM THE WEST. THE
EVENING RUN OF THE NAM CONTINUES WITH THE SAME SCENARIO OF THE
PAST FEW DAYS. AN ANOMOLOUSLY STRONG UPPER JET WILL BE DRIVING THE
SYSTEM...ASSISTING WITH THE PRODUCTION OF QUASI-GEOSTROPHIC
FORCING FOR ASCENT. NORTHEAST COLORADO WILL BE POSITIONED UNDER
THE FAVORABLE LEFT EXIT REGION OF THE JET FROM TOMORROW MORNING
THROUGH FRIDAY MORNING. MOISTURE FROM THE NEXT SYSTEM WILL BE
MOVING INTO THE MOUNTAINS BY LATE MORNING WITH SNOW DEVELOPING.
PRECIPITATION ON THE PLAINS WILL PROBABLY WAIT UNTIL AFTERNOON TO
DEVELOP...PROBABLY IN THE FORM OF RAIN. BY EARLY EVENING A
TRANSITION TO SNOW IS EXPECTED. THE LATEST RUN OF THE NAM STILL
INDICATES 4+ INCHES OF SNOW SOMEWHERE ALONG THE I-25 CORRIDOR BY
FRIDAY MORNING. THE PRESENCE OF THE STRONG JET ALOFT IS GOING TO
LEAD TO BANDED PRECIPITATION...BUT WE WILL HAVE TO WAIT TIL
TOMORROW AFTERNOON TO SEE WHERE INDIVIDUAL BANDS BEGIN SETTING UP.
SCENARIOS DEPICTED IN THE AFTERNOON PACKAGE WILL BE GOOD FOR NOW.
WILL UPDATE ZONES TO CLEAN OUT THE MENTION OF SHOWERS EARLIER THIS
EVENING.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 315 PM MDT WED APR 1 2015

HIGH BASED CONVECTION HAS DEVELOPED AS EXPECTED. GUSTY WINDS AND
A FEW LIGHTNING STRIKES NOTED WITH A FEW OF THESE. SOME SNOW ALSO
SEEN OVER THE HIGHER MOUNTAINS MAINLY IN ELEVATIONS ABOVE 10-11
THOUSAND FEET. THE SHORT WAVE DRIVING THESE SHOWERS AND STORMS
WILL MOVE TO THE EAST THIS EVENING...WHILE THE LOSS OF DAYTIME
HEATING WILL ALSO ALLOW THESE SHOWERS TO DECREASE. THEY SHOULD BE
EAST OF THE I-25 CORRIDOR BY 8-9 PM AND TO THE EASTERN BORDER
BEFORE MIDNIGHT.

AFTER MIDNIGHT...DONT SEE MUCH SHOWER THREAT ALTHOUGH A WEAK FRONT
COMING DOWN THE EAST SIDE OF THE ROCKIES SHOULD PRODUCE UPSLOPE
AND A LOW RISK OF SHOWERS BEFORE DAYBREAK. HAVE REDUCED THOSE POPS
A BIT.

ON THURSDAY...WE EXPECT SOME LIGHT RAIN AND SNOW TO DEVELOP ON
THE PLAINS IN THE MORNING...ALTHOUGH MOST OF THIS IS NOW POINTING
TO THE NORTH OF DENVER AS ANY UPSLOPE COMPONENT IS VERY SHALLOW
AND SOUTHEASTERLY. THERE IS INITIALLY MORE MOISTURE AND LIFT TO
THE NORTH SO WILL HAVE BEST POPS THERE THROUGH EARLY AFTERNOON. BY
MID TO LATE AFTERNOON...ANOTHER BUT STRONGER FRONT IS EXPECTED TO
PUSH ACROSS THE PLAINS. IT IS DURING THIS PERIOD WHEN RAIN/SNOW
MIX SHOULD CHANGE OVER TO ALL SNOW AND BECOME HEAVIER AS
COMBINATION OF UPSLOPE...STRONGER Q-G...AND DEEPER MOISTURE JOIN
FORCES. WILL HAVE HIGHEST POPS AND MOST SNOW ACCUMULATION RESERVED
FOR THIS PERIOD ALTHOUGH MOUNTAIN/FOOTHILLS AREAS NEAR THE WY
BORDER COULD SEE A COUPLE OF INCHES THURSDAY MORNING. FOR THE
FRONT RANGE URBAN CORRIDOR AND ADJACENT PLAINS...SNOW ACCUMULATION
WILL DEPEND HIGHLY ON SNOW RATES SO A CONSERVATIVE ACCUMULATION
FORECAST FOR THE DAYTIME HOURS SEEMS PRUDENT...ONLY AROUND 1 INCH
ON GRASSY SURFACES. MAIN THREAT FOR ACCUMULATIONS IN LOWER
ELEVATIONS WOULD HOLD OFF UNTIL THURSDAY EVENING AS TEMPERATURES
COOL. HAVE HELD OFF ON ANY HIGHLIGHTS FOR NOW CONSIDERING MOST OF
THIS STARTS LATER SECOND PERIOD INTO THE THIRD PERIOD. AT THIS
TIME...EAST SLOPES OF THE FRONT RANGE MOUNTAINS AND FOOTHILLS LOOK
SOLID ADVISORY AMOUNTS...AND POSSIBLE ADVISORY FOR I-25 URBAN
CORRIDOR/PALMER DIVIDE DEPENDING ON SNOW INTENSITY AND TEMPS.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 315 PM MDT WED APR 1 2015

PRECIPITATION WILL CONTINUE ACROSS NORTH CENTRAL AND NORTHEASTERN
COLORADO THURSDAY NIGHT AS THE UPPER LEVEL STORM SYSTEM MOVES ACROSS
THE CENTRAL ROCKIES. TEMPERATURES LOOK COLD ENOUGH TO BE ALL SNOW
OVER THE MOUNTAINS...FOOTHILLS...PALMER DIVIDE AND ADJACENT PLAINS.
WET BULB TEMPERATURE FORECASTS INDICATE THAT A RAIN SNOW MIX FURTHER
EAST ON THE PLAINS MUCH OF THE EVENING. QG LIFT ASSOCIATED WITH THE
UPPER JET OVER SOUTHERN COLORADO WILL AID IN THE
PRECIPITATION...WHILE THE POST FRONTAL UPSLOPE FLOW WILL ENHANCE
SNOWFALL AMOUNTS IN AND NEAR THE FOOTHILLS. IT LOOKS LIKE THE
MAIN THREAT FOR ACCUMULATING SNOW IN THE DENVER AREA WILL BE
DURING THE EVENING HOURS. PRECIPITATION SHOULD BEGIN TO TAPER OFF
FROM NORTH TO SOUTH AFTER MIDNIGHT...WITH PRECIPITATION ENDING
ACROSS THE FOOTHILLS AND PALMER DIVIDE BY DAYBREAK FRIDAY.
SNOWFALL AMOUNTS WILL BE A LITTLE TRICKY WITH THIS SYSTEM DUE TO
THE FACT THAT SURFACE TEMPERATURES ARE QUITE WARM. THE GFS...NAM
AND ECMWF ALL SHOW 6 TO 8 INCHES OF SNOW IN METRO DENVER...WHICH I
THINK IS SOMEWHAT TOO HIGH. MY BEST ESTIMATE IS THAT SNOWFALL
AMOUNTS WILL RANGE FROM 2 TO 6 INCHES ALONG THE FRONT RANGE URBAN
CORRIDOR AND PALMER DIVIDE...6 TO 12 INCHES ALONG THE FRONT RANGE
FOOTHILLS AND A TRACE TO 4 INCHES FURTHER EAST ON THE PLAINS BY
FRIDAY MORNING. MUCH DRIER CONDITIONS ARE EXPECTED ACROSS
NORTHEASTERN COLORADO BY MID FRIDAY MORNING AS A DOWNSLOPE FLOW
DEVELOPS EAST OF THE MOUNTAINS. SOME LINGERING MOISTURE COMBINED
WITH SOME OROGRAPHICS COULD PRODUCE SOME SCATTERED SNOW SHOWERS
ACROSS THE HIGHER MOUNTAINS THROUGH NOON.

ABOVE NORMAL TEMPERATURES ARE EXPECTED ACROSS THE PLAINS OVER THE
WEEKEND...DUE TO UPPER LEVEL HIGH PRESSURE AND WEAK DOWNSLOPE
FLOW. WE COULD SEE TEMPERATURES IN DENVER IN THE LOW 70`S ON
SUNDAY. MILD AND DRY WEATHER WILL CONTINUE EARLY NEXT WEEK AS DRY
SOUTHWESTERLY FLOW ALOFT DOMINATES THE ROCKY MOUNTAIN REGION.
COOLER UNSETTLED WEATHER WILL RETURN TO NORTH CENTRAL AND
NORTHEASTERN COLORADO BY THE MIDDLE OF NEXT WEEK...AS ANOTHER
STORM SYSTEM TAKES SHAPE OVER THE WESTERN U.S.

&&

.AVIATION...(FOR THE TAFS THROUGH 06Z THURSDAY EVENING)
ISSUED AT 914 PM MDT WED APR 1 2015

EAST AND NORTHEAST WINDS ARE EXPECTED OVERNIGHT AS THE DOMINANT
SURFACE LOW IS OVER SOUTHWEST KANSAS AND HIGH PRESSURE WILL BE
BUILDING INTO COLORADO FROM THE NORTH. VFR CEILINGS ARE EXPECTED
THROUGH SUNRISE...BUT THEN LOWER CEILINGS WILL BE MOVING IN BY
MIDDAY. LOWER CONDITIONS WITH A MIX OF RAIN AND SNOW SHOULD
PREVAIL THROUGH THE AFTERNOON AND THEN SNOW AND IFR SHOULD BE
EXPECTED TOMORROW NIGHT.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...DANKERS
SHORT TERM...BARJENBRUCH
LONG TERM...KALINA
AVIATION...DANKERS


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