Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 220920
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
320 AM MDT FRI AUG 22 2014

.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 318 AM MDT FRI AUG 22 2014

AN UPPER LEVEL LOW OVER CENTRAL ARIZONA WILL GRADUALLY MOVE NE
INTO THE FOUR CORNERS BY MIDDAY AND THEN INTO NE COLORADO BY EARLY
THIS EVENING. AS THIS FEATURE MOVES ACROSS A DECENT SHOT OF MID
LVL QG ASCENT WILL OCCUR AS WELL. AT THE SFC LOW PRES WILL EXTEND
FM SC WY INTO SERN CO WITH A WK SFC HIGH OVER WRN NEBRASKA. THIS
WILL ALLOW FOR ESE LOW LVL FLOW TO DVLP BY MIDDAY OVER NERN CO AND
ALLOW FOR DEEPER LOW LVL MOISTURE TO ADVECT INTO THE PLAINS.
OVERALL SHOULD SEE A GOOD CHC OF SHOWERS AND TSTMS ACROSS MUCH OF
THE AREA STARTING IN THE MTNS BY MIDDAY AND THEN SPREADING ACROSS
THE PLAINS BY EARLY EVENING.

PRECIPITABLE WATER VALUES ARE FCST TO BE AROUND AN INCH IN THE
MTNS WITH 1.25 TO 1.5 INCHES OVER THE PLAINS SO THE STORMS WILL
PRODUCE HEAVY RAIN...HOWEVER THEY WILL BE QUICK MOVING DUE TO
RATHER STG MID LVL FLOW. THERE WILL BE SOME POTENTIAL FOR TRAINING
OF CELLS OVER THE PLAINS SO COULD SEE A FEW SPOTS RECEIVE FM 2 TO
3 INCHES OF RAIN. AS FOR SVR POTENTIAL MAIN THREAT WOULD BE STRONG
WINDS DUE TO WET MICROBURSTS. ALSO CAN NOT RULE OUT A FEW
TORNADOES AS WELL AS STORM RELATIVE HELICITIES INCREASE BY LATE
AFTN INTO THE EARLY EVENING HOURS OVER THE PLAINS. AS FOR HIGHS
THIS AFTN WILL KEEP READINGS IN THE UPPER 70S TO MID 80S OVER THE
PLAINS.

BY TONIGHT AS MAIN DISTURBANCE MOVES QUICKLY NE SHOULD SEE PRECIP
CHANCES DECREASE ALONG THE FRONT RANGE BY EARLY EVENING AND THEN
BY MIDNIGHT OVER THE FAR NERN PLAINS. SOME MOISTURE MAY LINGER IN
THE NRN MTNS OVERNIGHT SO WILL KEEP IN A CHC OF SHOWERS MAINLY
NORTH OF I-70.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 318 AM MDT FRI AUG 22 2014

A DRIER SOUTHWESTERLY FLOW ALOFT WILL BE OVER NERN CO EARLY
SATURDAY FOLLOWING THE PASSAGE OF THE UPPER LEVEL TROUGH. THIS
WILL BE SHORT LIVED...AS ANOTHER SYSTEM OVER SRN IDAHO AT 12Z
SATURDAY MAKES ITS WAY ACROSS MONTANA/WYOMING LATE SATURDAY
AFTERNOON AND SATURDAY NIGHT. THE FLOW ALOFT OVER COLORADO WILL
INCREASE FM THE WEST WITH SCATTERED SHOWERS AND THUNDERSTORMS IN
THE MOUNTAINS. ALONG THE FRONT RANGE FOOTHILLS...URBAN CORRIDOR
AND ADJACENT PLAINS WILL MINIMIZE THE POPS SOUTH AND EAST OF
DENVER WITH HIGHER POPS TO THE NORTH AND WEST....AS THE TROF AXIS
BRUSHES ACROSS THE STATE. SUNDAY AND SUNDAY NIGHT...A DRIER
WESTERLY FLOW ALOFT WILL BE OVER THE CWA. IT WILL BE STABLE AND
COOLER FOLLOWING THE PASSAGE OF A COLD FRONT SATURDAY NIGHT INTO
SUNDAY MORNING. THE NAM12/ECMWF GENERATE LITTLE QPF OVER THE
REGION ON SUNDAY WHILE THE GFS DOES REFLECTS MORE SUBTROPICAL
MOISTURE EMBEDDED IN THE FLOW. WL LEAN TOWARD THE NAM12/ECMWF
SOLUTIONS WITH MINIMAL POPS MAINLY OVER THE MOUNTAINS IN THE
AFTN/EVNG. SUNDAY NIGHT INTO MONDAY...THE FLOW ALOFT BECOMES MORE
SOUTHWESTERLY WHICH MAY HELP TAP INTO THE SUBTROPICAL MOISTURE
OVER ERN AZ/NEW MX. POPS STILL ON THE LOW SIDE MONDAY
AFTERNOON/EVENING. THE NEXT SYSTEM IS PROGGED TO DROP OUT OF THE
NORTHERN ROCKIES AND ACROSS COLORADO TUESDAY AND TUESDAY NIGHT.
THE TROUGH AXIS AND ITS ASSOCIATED COLD FRONT WILL PASS ACROSS
NORTHERN COLORADO ON TUESDAY. IT WILL BE COOLER WITH A BETTER
CHANCE OF SHOWERS AND TSTMS AT THAT TIME. WEDNESDAY INTO
THURSDAY...AN UPPER RIDGE DEVELOPS OVER THE WESTERN U.S. WITH A
DRIER NORTHWESTERLY FLOW ALOFT OVER COLORADO. AS A RESULT...LESS
POPS WITH MODERATING TEMPERATURES FOR THE MIDDLE OF NEXT WEEK.

&&

.AVIATION...(FOR THE TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 318 AM MDT FRI AUG 22 2014

TSTMS WILL INCREASE IN COVERAGE AND INTENSITY BY EARLY TO MID AFTN
WITH HIGHEST THREAT FM 21Z-01Z.  POTENTIAL EXISTS FOR STRONG STORMS
WHICH MAY PRODUCE HEAVY RAIN AND GUSTY WINDS TO 50 MPH.  COULD SEE
VISIBILITIES DROP DOWN TO 1-3 MILES WITH CEILINGS BLO 3000 FT FOR
PERIODS UP TO 30 MINUTES ANY TIME BETWEEN 21Z AND 01Z IF AIRPORTS
TAKE A DIRECT HIT FM STORMS. AFTER 01Z CONDITIONS SHOULD IMPROVE AS
TSTMS MOVE OFF TO THE NE IN ASSOCIATION WITH THE DISTURBANCE
MENTIONED ABV.

AS FOR WINDS THEY LOOK GENRALLY LIGHT AND VARIABLE THIS MORNING BUT
SHOULD BECOME MORE ESE BY 18Z.  AS STORMS MOVE ACROSS LATER THIS
AFTN EXPECT CHAOTIC SFC WINDS BETWEEN 21Z AND 01Z.  FOR TONIGHT
WINDS SHOULD GRADUALLY BECOME DRAINAGE BY 06Z OR SO.


&&

.HYDROLOGY...
ISSUED AT 318 AM MDT FRI AUG 22 2014

STORMS WILL MOVE QUICKLY TODAY HOWEVER THERE WILL BE SOME POTENTIAL
FOR TRAINING OF STORMS OVER NORTHEAST COLORADO AS A FEW LOCATIONS
COULD SEE UP TO 2 INCHES OF RAIN IN LESS THAN HOUR.  IN THE
FOOTHILLS AND MTNS ISOLATED AMOUNTS UP TO AN INCH IN LESS THAN AN
HOUR WILL BE POSSIBLE WITH SOME MINOR FLOODING IN THE BURN SCARS.

&&

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

$$

SHORT TERM...RPK
LONG TERM...COOPER
AVIATION...RPK
HYDROLOGY...RPK



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