Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 130332
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
932 PM MDT SAT JUL 12 2014

.UPDATE...
ISSUED AT 930 PM MDT SAT JUL 12 2014

ADDITIONAL HEAVY RAIN AND FLASH FLOOD THREAT DECREASING RAPIDLY
THIS EVENING AS AIRMASS IS STABILIZING IN RAIN COOLED AIRMASS. THE
ONLY THREAT AREA WOULD BE FAR SOUTHERN LINCOLN COUNTY SO WILL
MONITOR THAT LOCATION THROUGH MIDNIGHT.

THERE HAS BEEN CONTINUED REDEVELOPMENT IN THE SOUTHERN
FOOTHILLS...BUT MOST OF THESE WILL CONTINUE TO DRIFT SOUTHEAST AND
PRODUCE JUST BRIEF MODERATE RAIN. THERE WAS ANOTHER BATCH OF
SHOWERS AND STORMS HEADING SOUTH FROM WYOMING...SO CANT RULE OUT
A FEW OF THESE SNEAKING BACK INTO THE NORTHERN BORDER AREA.
OVERALL...DECREASING CHANCES OF SHOWERS AND STORMS IS ON TRACK FOR
THE NIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 148 PM MDT SAT JUL 12 2014

AIRMASS IS VERY MOIST WITH PRECIPITABLE WATER VALUES GREATER THAN AN
INCH AND DEW POINTS IN THE MID 50S TO LOWER 60S. CAPES ARE ROUGHLY
700 TO 1300 J/KG. THUNDERSTORMS WILL CONTINUE TO BUILD OVER THE
MOUNTAINS AND FOOTHILLS AND SPREAD EAST ONTO THE PLAINS THIS
AFTERNOON AND EVENING. THE THREAT FOR HEAVY RAIN WITH POSSIBILITY OF
FLASH FLOODING WILL CONTINUE INTO THE EVENING. CURRENT STORMS ARE
NOT MOVING MUCH OVER NORTHEAST PARK AND EL PASO COUNTIES. WILL
CONTINUE WITH FLASH FLOOD WATCH THROUGH MID EVENING. THE STORMS OVER
LARIMER COUNTY ARE MOVING EAST AROUND 15 TO 20 MPH. THIS AND DRIER
AIR MOVING IN THIS EVENING WILL KEEP THE FLASH FLOOD THREAT LOW.
CHANCE FOR SHOWERS AND STORMS WILL END FROM THE NORTH FIRST AS DRIER
AIR MOVES IN FROM THE NORTHEAST AT THE MID LEVELS. STILL COULD SEE A
FEW LINGERING SHOWERS LATE TONIGHT...MAINLY SOUTH AND EAST.

NORTHWEST FLOW ALOFT WILL INCREASE AS UPPER LEVEL RIDGE INTENSIFIES
OVER THE GREAT BASIN. PRECIPITABLE WATER VALUES FALL TO AROUND AN
INCH...WHICH IS STILL SOMEWHAT MOIST. A WEAK DISTURBANCE EMBEDDED IN
THE FLOW ALOFT WILL TRIGGER SCATTERED STORMS SUNDAY AFTERNOON. DUE
TO DRIER AIR AND STRONGER FLOW ALOFT...THE THREAT FOR HEAVY RAIN AND
FLASH FLOODING WILL BE LOWER. SHEAR WILL INCREASE...HOWEVER CAPES
WILL BE LOW...LESS THAN A 1000 J/KG...SO THE SEVERE THREAT WILL BE
LOW TOO. THE NORTHWEST FLOW WILL KEEP COOLER AIR OVER THE AREA.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 148 PM MDT SAT JUL 12 2014

MODELS HAVE MODERATELY STRONG NORTHWESTERLY FLOW ALOFT OVER THE
FORECAST AREA SUNDAY NIGHT THROUGH TUESDAY NIGHT. BASICALLY...THE
MODELS HAVE A SIGNIFICANT UPPER TROUGH/CLOSED LOW OVER THE GREAT
LAKES WITH THE UPPER RIDGE CENTER OF OVER THE GREAT BASIN ALL FIVE
PERIODS. THE QG VERTICAL VELOCITY FIELDS HAVE WEAK UPWARD MOTION
FOR THE CWA MOST OF THE TIME. FOR THE MOST PART...THE BOUNDARY
LAYER FLOW HAS AN EASTERLY COMPONENT TO IT FROM THE DIVIDE
EASTWARD ALL FIVE PERIODS. FOR MOISTURE...THERE IS PLENTY THE
WHOLE TIME. PRECIPITABLE WATER VALUES ARE PROGGED FROM 0.8 TO 1.2
INCHES FOR THE PLAINS AND FOOTHILLS SUNDAY NIGHT THROUGH TUESDAY
NIGHT. THE LOW LEVEL DEW POINT PROGGS HAVE 50 TO LOWER 60S F
READINGS FOR THE PLAINS AND FOOTHILLS ALL FIVE PERIODS. THE CAPE
IS FAIR SUNDAY EVENING...THE HIGHEST VALUES ARE OVER THE
FOOTHILLS. FOR LATE DAY MONDAY...THERE IS CAPE OVER THE WESTERN
TWO-THIRDS OF THE CWA...BEST IN THE MOUNTAINS...WITH PRACTICALLY
NOTHING OVER THE NORTHEAST CORNER. ON LATE DAY TUESDAY...THERE IS
SIGNIFICANT CAPE OVER THE WESTERN HALF OF THE PLAINS...SOME AREAS
WITH OVER 2000 J/KG. THE QPF FIELDS SHOW SOME MEASURABLE RAINFALL
ACROSS ALL THE CWA THE DAY DAY PERIODS. THE BEST AMOUNTS ARE
SUNDAY EVENING AND TUESDAY LATE DAY. WILL STAY THE COURSE AND GO
WITH "CHANCES" FOR THE LATE DAY PERIODS. MONDAY`S HIGH
TEMPERATURES ARE CLOSE TO SUNDAY`S...MAYBE A TAD COOLER. TUESDAY`S
HIGHS ARE SIMILAR AS WELL. FOR THE LATER DAYS...WEDNESDAY THROUGH
SATURDAY...MODELS KEEP THE UPPER RIDGE WEST OF COLORADO INTO
FRIDAY...THEN IT MIGRATES EASTWARD TO BE SOUTH OF COLORADO BY
SATURDAY. MOISTURE IS PRETTY GOOD THROUGH THURSDAY THEN THINGS DRY
OUT.

&&

.AVIATION...(FOR THE TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 930 PM MDT SAT JUL 12 2014

SHOWER AND STORM THREAT HAS PUSHED JUST SOUTH OF THE FRONT RANGE
AIRPORTS AND SHOULD REMAIN THERE LATE THIS EVENING. ONLY A SLIGHT
CHANCE OF A PASSING LIGHT SHOWER OVERNIGHT. IF WE GET MID LEVEL
DECK TO BREAK...THEN THERE WOULD BE A THREAT OF FOG AND/OR STRATUS
WITH IFR/MVFR CONDITIONS DEVELOPING 11Z-14Z. OTHERWISE LOOK FOR
ANOTHER CHANCE OF STORMS SUNDAY AFTER 21Z ALTHOUGH STORM THREAT IS
A LITTLE LOWER THAN TODAY.

&&

.HYDROLOGY...
ISSUED AT 920 PM MDT SAT JUL 12 2014

FLASH FLOOD THREAT HAS DECREASED SIGNIFICANTLY AS AIRMASS
STABILIZES IN OUTFLOW COOLED AIR. STILL A FEW SHOWERS PRODUCING
BRIEF MODERATE TO HEAVY RAIN IN THE FOOTHILLS OF JEFFERSON/CLEAR
CREEK/PARK COUNTIES...BUT SHOWERS ARE SMALL AND UPSLOPE FLOW IS
WEAKENING. ADDITIONAL RAINFALL AMOUNTS AROUND ONE HALF INCH AT
MOST EXPECTED IN THOSE LOCALES. OTHERWISE RAINFALL AMOUNTS LESS
THAN ONE QUARTER INCH OVERNIGHT.

THERE WILL BE SHOWERS AND THUNDERSTORMS AGAIN ON SUNDAY...THOUGH
FEWER THAN TODAY. THE FLASH FLOOD THREAT WILL BE LOWER SUNDAY DUE TO
STRONGER FLOW ALOFT PUSHING STORMS ALONG AND A DRIER AIRMASS.

&&

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

$$

UPDATE...BARJENBRUCH
SHORT TERM...MEIER
LONG TERM...RJK
AVIATION...BARJENBRUCH
HYDROLOGY...BARJENBRUCH/MEIER


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