Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 170226
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
826 PM MDT WED JUL 16 2014

.UPDATE...
ISSUED AT 813 PM MDT WED JUL 16 2014

WATER VAPOR IMAGERY SHOWING UPPER LEVEL TROF OVER CENTRAL WYOMING
AND CONTINUES TO SLOWLY SAG SOUTHWARD TOWARDS COLORADO. STILL
QUITE A BIT OF CONTINUED SHOWER ACTIVITY WITH EMBEDDED
THUNDERSTORMS OVER WESTERN AND CENTRAL CWA BUT DOES SEEM TO BE
A SHIFT IN THE BULK OF THE PRECIP FURTHER SOUTH OVER TIME ACROSS
THE CWA. LOOKS LIKE LAST GASP OF SHOWERS JUST MOVING SOUTH OF CYS
AND INTO NORTHERN LARIMER AND WELD COUNTIES. EXPECT A GRADUAL
DECREASE IN SHOWERS EXPECTED OVERNIGHT. WILL MAKE SOME MINOR
ADJUSTMENTS TO FORECAST BASED ON CURRENT AND ANTICIPATED TRENDS IN
SHOWER ACTIVITY. STRONGER STORMS STILL PRODUCING VERY HEAVY RAIN
BUT MOVEMENT OF STORMS QUICK ENOUGH TO KEEP OVERALL FLOOD THREAT
ON THE LOW SIDE.  WITH SOME CLEARING EXPECTED LATER TNT COULD BE
SOME AREAS OF DEVELOPING.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 337 PM MDT WED JUL 16 2014

BANDS OF CONVECTION...I.E. SHOWERS/T-STORMS...WERE MIGRATING SEWRD
ACRS NERN COLORADO ATTM BENEATH A STRONG NORTHWEST FLOW ALOFT.
DEVELOPING CONVECTION IN RESPONSE TO INCREASING QG ASCENT AHEAD
OF A MID-LEVEL SHORTWAVE TROUGH SWINGING SEWRD ACRS CENTRAL
WYOMING ATTM. STORMS WERE FILLING IN ACRS NORTHERN SECTIONS OF
THE CWA AND ALONG THE FRONT RANGE. STORM MOTIONS RUNNING AROUND
28KTS WHICH UP TO NOW HAS REDUCED THE RISK OF HEAVY RAIN. THIS
MAY CHANGE OVER THE NEXT SEVERAL HOURS AS LARGE SCALE LIFT AND
INSTABILITY INCREASE AHEAD OF THE SHORTWAVE AND AS PRECIPITABLE
WATER VALUES CREEP UP WITH SELY BNDRY LAYER FLOW FARTHER OUT ON
THE PLAINS. SHOULD SEE THE POTENTIAL FOR HEAVY RAINERS INCREASE
OVER THE NEXT 2-4 HOURS...MAINLY OVER AND ALONG THE FRONT
RANGE INCLUDING THE DENVER METRO AREA. MESOSCALE MODELS INDICATE
RAINFALL RATES APPROACHING AN INCH PER HOUR IN THESE AREAS.
COOLING ALOFT MAY ALSO SUPPORT HAIL PRODUCTION BUT THE CURRENT
TEMPERATURE PROFILE AND VERTICAL VELOCITY RATES MAY ONLY SUPPORT
STONES NO LARGER LARGE THAN NICKLE SIZE. GOOD BET EASTERN PORTIONS
OF THE CWA WILL SEE A SERIES OF SHOWER/STORM BANDS MOVING SEWRD
ACRS THE AREA THROUGH LATE EVENING...CENTERED DURING THE PERIOD
22Z/WED TO 04Z/THU THIS EVENING. THEN...STORM ACTIVITY SHOULD
STEADILY DROP OFF AS DRIER AND MORE STABLE AIR ALOFT BEGINS
FILTERING IN WITH THE PASSING SHORTWAVE. HOWEVER BOUNDARY LAYER
MOISTURE SHOULD REMAIN HIGH OVERNIGHT CAUSING AREAS OF STRATUS
AND FOG ON THE PLAINS THROUGH SUNRISE. WITH PARTIAL CLEARING
TOWARD DAWN MAY SEE POCKETS OF DENSE FOG IN LOW LYING AREA NORTH
AND EAST OF DENVER.

ON THURSDAY...WITH DRYING AND WARMING ALOFT BEHIND THE EXITING
SHORTWAVE TROUGH...SHOULD SEE A SIGNIFICANT DROP OFF IN SHOWER/STORM
COVERAGE. SFC TEMPERATURES ALSO WARMER BY AS MUCH AS 2-3C WARMER
ON THE PLAINS. LOOKING FOR THE FOG TO BURN OFF PROBABLY BEFORE 8
AM ALONG THE FOOTHILLS AND BY AROUND MID-MORNING IN THE PLATTE
RIVER VALLEY. SHOULD SEE SFC DEWPOINTS SLIDING THROUGH THE
DAY...ESPLY ALONG THE FRONT RANGE WITH DEVELOPING DOWNSLOPE FLOW.
MAY STILL SEE A FEW STORMS FORMING OVER THE FRONT RANGE BY EARLY
AFTERNOON WITH HEATING AND OROGRAPHICS...THEN DRIFTING SEWRD OVER
THE ADJACENT PLAINS. RAINFALL RATES WILL BE MUCH LOWER WITH
DECREASING PW AMOUNTS. OTHERWISE LOOKING FOR A DAY ABOUT THE SAME
IN THE HIGH COUNTRY...BUT SLIGHTLY WARMER.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 337 PM MDT WED JUL 16 2014

SOME THUNDERSTORMS POSSIBLE ACROSS THE HIGHER TERRAIN DURING THE
EVENING...OTHERWISE PARTLY CLOUDY SKIES TO PREVAIL. BRIEF
MODERATE RAIN EXPECTED WITH SOME OF THE STORMS.

ON FRIDAY...UPPER RIDGE BUILDS ACROSS THE DESERT SOUTHWEST
TOWARDS THE FOUR CORNERS AREA. AIRMASS BECOMES WARMER AND SLIGHTLY
DRIER THOUGH STILL SOME SUBTROPICAL MOISTURE OVER THE REGION.
PRECIPITABLE WATER VALUES DECREASE TO LESS THAN AN INCH ACROSS THE
PLAINS. CAPE VALUES AROUND 700 TO 900 J/KG...HIGHEST FAR EASTERN
PLAINS. SOME STORMS POSSIBLE BY THE AFTERNOON...CONTINUING INTO
THE EVENING. FORECAST SOUNDINGS STILL INDICATE AN INVERTED-V TYPE
PROFILE. STORMS COULD PRODUCE BRIEF MODERATE TO HEAVY RAIN WITH A
BETTER CHANCE FOR GUSTY DOWNBURST WINDS. TEMPERATURES LOOK TO WARM
TO AROUND 90 DEGREES ACROSS THE PLAINS.

FOR SATURDAY AND SUNDAY...MODELS SHOW UPPER RIDGE SHIFTING INTO
COLORADO WITH WEAKENING WEST NORTHWEST FLOW ALOFT. SOME INCREASE
IN SUBTROPICAL MOISTURE OVER THE AREA...MAINLY ACROSS THE
MOUNTAINS. THUNDERSTORMS WILL BE POSSIBLE DURING THE AFTERNOON AND
EVENING HOURS...MAINLY ACROSS THE MOUNTAINS. CROSS SECTIONS
INDICATE MOST OF THE MOISTURE TO BE ABOVE 6000 FEET...SO GUSTY
DOWNBURST WINDS A POSSIBILITY. STORM MOTION SLIGHTLY SLOWER...WITH
SOME STORMS PRODUCING BRIEF HEAVY RAIN. HIGHS ACROSS THE PLAINS TO
BE IN THE LOWER 90S BOTH DAYS. FOR THE LATER PERIODS...MONDAY
THROUGH WEDNESDAY. BOTH GFS AND ECMWF SHOW UPPER RIDGE OVER THE
AREA MONDAY. SOME MODEL DIFFERENCES TUESDAY AND WEDNESDAY WITH THE
GFS SHOWING THE RIDGE AXIS SHIFTING EAST INTO WESTERN KANSAS WITH
SOUTHWEST FLOW ALOFT DEVELOPING. ECMWF STILL KEEPS THE RIDGE AXIS
ACROSS COLORADO. THUS...ECMWF KEEPS SOME SUBTROPICAL MOISTURE OVER
COLORADO WHILE THE GFS SHIFTS IT EASTWARD. FOR NOW WILL CONTINUE
WITH A SLIGHT CHANCE OF LATE DAY THUNDERSTORMS...MAINLY ACROSS THE
MOUNTAINS. LITTLE CHANGE IN DAY TO DAY TEMPERATURES EXPECTED.

&&

.AVIATION...(FOR THE TAFS THROUGH 06Z THURSDAY EVENING)
ISSUED AT 813 PM MDT WED JUL 16 2014

STILL EXPECT CONTINUED SHOWERS WITH EMBEDDED THUNDERSTORMS AT
BJC/APA WITH LESSER CHANCES AT KDEN AS MAIN SWATH OF SHOWERS HAVE
SHIFTED ABOUT SOUTH. STILL KEEP IN SOME STRATUS AND FOG LATER TNT
WITH PARTIAL CLEARING AFTER MIDNIGHT.

&&

.HYDROLOGY...
ISSUED AT 337 PM MDT WED JUL 16 2014

RAIN SHOWERS AND THUNDERSTORMS ARE LIKELY THROUGH LATE THIS
EVENING OVER AND EAST OF THE FRONT RANGE. SOME OF THE STORMS MAY
PRODUCE HEAVY RAINFALL...EVEN WITH STORM MOTIONS OF 25-30 MPH.
TRAINING STORMS ARE LIKELY TO PRODUCE THE HEAVIEST RAIN AMOUNTS.
STORM TOTALS UP TO AN INCH IN UNDER AN HOUR ARE POSSIBLE BETWEEN 4
PM AND 10 PM MDT...AND MAINLY OVER AND NEAR THE FRONT RANGE
FOOTHILLS. BURN SCARS WILL BE MOST SUSCEPTIBLE TO THE HEAVY
RAINFALL WITH A SLIGHT CHANCE OF FLASH FLOODING. STORM AND
SHOWER ACTIVITY SHOULD DROP OFF STEADILY AFTER MIDNIGHT. THURSDAY
LOOKS DRIER AND WARMER.

FRIDAY THROUGH TUESDAY...SOME STORMS POSSIBLE DURING THE AFTERNOON
AND EVENING...MAINLY OVER THE MOUNTAINS. LOW LEVELS DRIER...SO
STORMS COULD PRODUCE BRIEF MODERATE RAIN. THE FLASH FLOOD THREAT
IS EXPECTED TO BE LOW THROUGH THE PERIOD.

&&

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

$$

UPDATE...ENTREKIN
SHORT TERM...BAKER
LONG TERM...D-L
AVIATION...ENTREKIN
HYDROLOGY...BAKER



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