Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 210213
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
813 PM MDT SAT SEP 20 2014

.UPDATE...
ISSUED AT 812 PM MDT SAT SEP 20 2014

EARLIER CONVECTION WITH LOCALLY HEAVY RAINFALL IS DECREASING IN
INTENSITY BUT IT IS MOVING SLOWLY EAST ONTO THE NEARBY ADJACENT
PLAINS. THE MAIN AREA OF EVENING SHOWERS AND ISOLATED STORMS WILL
LIKELY HOLD ALONG AND JUST SOUTH OF THE I-70 CORRIDOR...SO HAVE
ALREADY ADJUSTED FORECAST FOR HIGHER POPS PARK COUNTY/SOUTHERN
FOOTHILLS/DOUGLAS COUNTY AREA...AND LOWER POPS NORTHWARD TOWARD
FORT COLLINS. AT BEST WOULD SEE ONLY ISOLATED SHOWERS THERE. THE
EVENING SHOWERS/STORMS COULD VERY WELL EVENTUALLY DISSIPATE DURING
THE POST MIDNIGHT HOURS BUT THEN REDEVELOP AGAIN TOWARD EARLY
MORNING SUNDAY AS NEXT BATCH OF LIFT/MOIST PLUME REACHES THE
FORECAST AREA.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 1224 PM MDT SAT SEP 20 2014

MDLS CONTINUE TO MOISTEN UP THE AIRMASS OVERNIGHT AND SUNDAY. FOR
THIS EVENING...THE LATEST HRRR APPEARS TO KEEP ANY DEVELOPING
THUNDERSTORMS IN THE MOUNTAINS WEST AND SOUTHWEST OF DENVER. THE
AIRMASS REMAINS TOO DRY AND STABLE ELSEWHERE TO SUPPORT ANY DEEP
CONVECTION. THE UPPER RIDGE WILL REMAIN OVER EASTERN COLORADO
TONIGHT...WITH LOW LEVEL ESELY SFC WINDS. THE UPPER LOW WILL BE
OVER SWRN NV SUNDAY MORNING AND WILL MOVE SLOWLY INTO NERN NV BY
00X MONDAY. THE QG ASCENT THROUGH THE PERIOD WILL BE WEAK BUT
PRECIPITABLE WATER VALUES WILL CLIMB BACK OVER AN INCH. WITH THE
COOLER AMS IN PLACE...LIMITED HEATING COUPLED WITH WEAK FORCING
ALOFT SHOULD ALLOW FOR MORE SHOWERS VS THUNDERSTORMS IN THE
FORECAST. WL CONTINUE WITH SCT-LIKELY POPS ACROSS THE MOUNTAINS
AND FOOTHILLS WITH MORE EMPHASIS ON SHOWERS IN THE GRIDS.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 230 PM MDT SAT SEP 20 2014

NOT A LOT OF DIFFERENCE IN THE MODEL SOLUTIONS DURING THE PERIOD.
THE UPPER LOW CURRENTLY WEST OF LOS ANGELES IS PREDICTED TO LIFT
TO THE NORTHEAST WITH ITS ASSOCIATED TROUGH PASSING EAST OF THE
STATE TUESDAY MORNING. THE RESULT OF THIS IS A QUANTITATIVELY
MODEST BUT DEEP AND PROLONGED PERIOD OF QUASIGEOSTROPHIC ASCENT
OVER MOST OF THE AREA BEGINNING TONIGHT AND CONTINUING THROUGH
MONDAY NIGHT. THIS ASCENT SHOULD DIMINISH FROM WEST TO EAST DURING
THE DAY TUESDAY AS UPPER LEVEL RIDGING OCCURS OVER THE CENTRAL
ROCKIES. CONSEQUENTLY EVERYONE SHOULD HAVE A SHOT AT SOME
PRECIPITATION AS THIS SYSTEM PASSES BY EARLY IN THE PERIOD WITH
DRIER CONDITIONS EXPECTED AFTER TUESDAY. PRECIPITABLE WATER
VALUES ARE FORECAST TO EXCEED 1.00 INCH WITH THIS SYSTEM AND WITH
MODERATE CAPE VALUES AROUND AT TIMES THE THREAT OF SOME HEAVY
SHOWERS CANNOT BE COMPLETELY RULED OUT IN THE SUNDAY NIGHT THROUGH
TUESDAY MORNING TIME FRAME. AT PRESENT HOWEVER IT IS DIFFICULT TO
SINGLE OUT ANY PARTICULAR AREA FOR ANY ENHANCED FLOODING THREAT.

&&

.AVIATION...(FOR THE TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 812 PM MDT SAT SEP 20 2014

SHOWERS AND ISOLATED EVENING STORMS SHOULD HOLD JUST SOUTH OF KDEN
AND KBJC BUT VCTS STILL POSSIBLE TIL AROUND 06Z. KAPA ON THE
OTHER HAND WILL SEE PERIODS OF SHOWERS/ISOLATED STORMS TIL AROUND
06Z...THEN LOOK FOR A DECREASE OF SHOWERS. NEXT BATCH COULD BE IN
TOWARD 12Z-15Z SUNDAY. CEILINGS LOOK A LITTLE LOWER THAN PREVIOUS
FORECAST SO WILL BE ADJUSTING THOSE DOWN SLIGHTLY WITH CEILINGS
POSSIBLY LOWERING TO AROUND 5000 FT AGL.

&&

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

$$

UPDATE...BARJENBRUCH
SHORT TERM...COOPER
LONG TERM...ET
AVIATION...BARJENBRUCH


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