Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 260314
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
914 PM MDT MON APR 25 2016

.UPDATE...
ISSUED AT 913 PM MDT MON APR 25 2016

SPRINGTIME IN THE ROCKIES IN FULL SWING WITH CONVECTIVE
DEVELOPMENT ON THE PLAINS...A COUPLE STORMS PRODUCING ONE HALF TO
ONE INCH DIAMETER MUSHY HAIL ON THE PLAINS...AND RAIN MIXING
WITH/CHANGING TO SNOW IN THE MOUNTAINS. CONVECTION IS EXPECTED TO
CONTINUE ACROSS THE PLAINS OVERNIGHT WITH DEEP LAYER LIFT AND
SUFFICIENT MID LEVEL INSTABILITY. BEST LOW/MID LEVEL THETA-E
ADVECTION SHIFTS TO THE NORTHERN BORDER AREA OVERNIGHT SO HIGHEST
POPS WILL EVENTUALLY SHIFT THAT WAY. SOME DRYING IS STILL EXPECTED
TO OCCUR FROM THE SOUTHWEST LATE TONIGHT/EARLY TUESDAY MORNING AS
DRY SLOT MOVES IN. HOWEVER...THERE IS STILL POTENTIAL INSTABILITY
AROUND AND DEEP LAYER LIFT SO CANT RULE OUT A FEW SHOWERS/STORMS
LINGERING THROUGH THAT TIME PERIOD EVEN ALONG AND SOUTH OF THE
I-70 CORRIDOR.

IN THE MOUNTAINS...COLD FRONT IS JUST MOVING IN SO RAIN WILL BE
CHANGING OVER TO SNOW OVER THE NEXT FEW HOURS. STILL ON TAP FOR 1
TO 4 INCH AMOUNTS OVERNIGHT WITH THE COLD ADVECTION...
INSTABILITY...AND SLIGHT IMPROVEMENT IN OROGRAPHICS.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 324 PM MDT MON APR 25 2016

UPPER LOW IN WESTERN UTAH WILL MOVE TO WESTERN COLORADO OVERNIGHT
THEN TO THE FRONT RANGE OF COLORADO TOMORROW. THE SURFACE LOW WILL
INTENSIFY IN EASTERN COLORADO TOMORROW MORNING...THEN MOVE TO
WESTERN KANSAS TUESDAY AFTERNOON.

SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP ACROSS THE
MOUNTAINS THE REST OF THIS AFTERNOON INTO EVENING...AND SOME WILL
SPILL TO THE PLAINS.

ON TUESDAY WITH SOUTHWESTERLY FLOW AHEAD OF THE UPPER
LOW...SEVERAL MODELS SHOWED A RATHER SIGNIFICANT DRY SLOT IN
EASTERN COLORADO...THIS LOOKED QUITE REASONABLE...AND I LOWERED
POPS NEAR THE PUEBLO CWA...WHILE KEEPING THEM SCATTERED TO LIKELY
ALONG THE WYOMING BORDER. ONLY MENTIONED THUNDERSTORMS IN FAR
NORTHEAST COLORADO PER THE SPC DAY 2 OUTLOOK. THE COLD FRONT WILL
DROP ACROSS NORTHEAST COLORADO IN THE WAKE OF THE SURFACE LOW.
EXPECT SHOWERS TO DEVELOP BEHIND THE COLD FRONT.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 324 PM MDT MON APR 25 2016

A VERY ACTIVE STORM TRACK PATTERN IN STORE FOR THE REMAINDER OF THE
WEEK...AND EVEN INTO EARLY NEXT WEEK. THOUGH MODELS AND THEIR
ENSEMBLE MEMBERS DIFFER ON THE SMALLER DETAILS...THE GENERAL
CONSENSUS IS FOR AT LEAST THREE LARGE SCALE UPPER AIR SYSTEMS TO
SPIN UP OVER THE GREAT BASIN AND/OR DESERT SOUTHWEST AND THEN SLOWLY
TRACK EAST-NORTHEASTWARD ACROSS THE CENTRAL ROCKY MOUNTAIN REGION
DURING THE PERIOD. THIS FIRST OF THESE CLOSED LOW SYSTEMS IS
ACCOMPANIED BY A COLD FRONT WHICH MODELS DROPPING SOUTH OUT OF
WYOMING TUESDAY AFTERNOON. BY EVENING...MODELS SHOW THE UPPER LOW
OVER THE NERN CORNER OF THE STATE PLACING MOST OF THE CWA UNDER A
STIFF NWLY FLOW...CONSEQUENTLY SUPPRESSING SHOWER ACTIVITY ON THE
PLAINS...PARTICULARLY ALONG THE FRONT RANGE...BUT NOT ENTIRELY.
WETBULB TEMPS LOWER ENOUGH FOR A MIX OF RAIN AND SNOW ON THE PLAINS
MAINLY WITHIN THE I-25 CORRIDOR AND PALMER DIVIDE. COULD SEE LIGHT
ACCUM ON THE DIVIDE NOT MOSTLY LIKELY NOTHING AT ELEVATIONS BELOW
5500 FEET.  ON WEDNESDAY...UPPER LOW LIFTS OUT AND A SHORTWAVE UPPER
RIDGE WITH SLIGHTLY DRIER AIR PASSES OVERHEAD. STILL NOT OUT OF THE
REACH OF THE UPPER LOW SO GUSTY NWLY WINDS A GOOD BET FOR MUCH OF
THE DAY ON THE PLAINS AND NRN FRONT RANGE. TEMPERATURES ON WEDNESDAY
GENERALLY 1-2 DEG C LOWER THAN THE DAY BELOW.

THE NEXT STORM SYSTEM THAT THE GFS...ECMWF AND CANADIAN MODELS SHOW
SPINNING UP OVER THE LOWER GREAT BASIN EARLY ON THURSDAY TRACKS
NEWRD ACRS THE FOUR CORNERS REGION ON FRIDAY AND COLORADO AND
WYOMING ON SATURDAY. STRENGTHENING SWLY FLOW AHEAD OF THIS SYSTEM
PUMPS ANOTHER DEEP FETCH OF MOISTURE UP INTO THE REGION AND
INCREASING MID-LEVEL DIVERGENCE PRIMES THE PUMP FOR THE NEXT ROUND
OF EXTENSIVE SHOWERS ACRS THE REGION. DO NOT SEE T-STORM DEVELOPMENT
THIS GO ROUND...BUT THERE`S A POTENTIAL FOR LOCALLY HEAVY UPSLOPE
PRECIP OVER AND ALONG THE FRONT RANGE FRIDAY NIGHT INTO SATURDAY.
WETBULB ZERO LEVEL DIFFERS QUITE A BIT FROM MODEL-TO-MODEL. SO
PINNING DOWN THE SNOW-LEVEL MAY NOT BE DETERMINED FOR ANOTHER DAY OR
TWO. FOR NOW WILL GO WITH HIGH SCATTERED POPS MTNS AND PLAINS. FOR
NOW SNOW IN THE HIGH COUNTRY...MAINLY RAIN ON THE PLAINS DURING THE
DAY FRIDAY AND SATURDAY...AND A RAIN/SNOW MIX FRIDAY NIGHT AND
SATURDAY NIGHT. BY SUNDAY...MODELS SHOW YET ANOTHER CLOSED UPPER LOW
PASSING THROUGH THE REGION. DETAILS ARE SKETCHY...BUT A CHANCE OF
SHOWERS LOOK REASONABLE FOR NOW.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY)
ISSUED AT 913 PM MDT MON APR 25 2016

SHOWERS AND THUNDERSTORMS MOVING NORTHEAST ACROSS THE DENVER METRO
AREA AIRPORTS WILL LIKELY SHIFT NORTH AND EAST OF KDEN BY 06Z.
THERE IS STILL A SLIGHT CHANCE OF THUNDER LINGERING PAST THAT
OVERNIGHT WITH THE POTENTIAL INSTABILITY AND LIFT IN PLACE.
OTHERWISE VFR CONDITIONS WILL PREVAIL. WINDS FINALLY SETTLING DOWN
TO MORE TYPICAL SPEEDS IN THE 8-15 KNOT RANGE OVERNIGHT...BUT
DIRECTION MAY STILL BE VARIABLE IN/NEAR THUNDERSTORMS AND DENVER
CYCLONE CONVERGENCE ZONE. COLD FRONT SHOULD PUSH BACK ACROSS
AIRPORTS 16Z-18Z TUESDAY. AIRMASS STILL UNSTABLE SO MORE SCATTERED
SHOWERS AND ISOLATED STORM THREAT TUESDAY AFTERNOON AND EVENING.
CEILINGS WILL LIKELY LOWER TO MVFR TOWARD 00Z-02Z WEDNESDAY.

&&

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

$$

UPDATE...BARJENBRUCH
SHORT TERM...RTG
LONG TERM...BAKER
AVIATION...BARJENBRUCH



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