Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS65 KBOU 201536
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
936 AM MDT WED AUG 20 2014

.UPDATE...
ISSUED AT 936 AM MDT WED AUG 20 2014

NOT PLANNING ON MAKING ANY CHANGES TO THINGS AT THIS POINT IN
TIME. GPS-MEASURED PRECIPITABLE WATER NUMBERS ARE UP QUITE A BIT
FROM YESTERDAY AT THIS TIME OVER THE PLAINS WITH LESS CHANGE OVER
THE MOUNTAINS AND WESTERN COLORADO. QUASIGEOSTROPHIC DYNAMICS WILL
BE PROVIDING SOME SUBSIDENCE OVER PARTS OF WESTERN COLORADO WHICH
MAY LESSEN THE CONVECTIVE ACTIVITY THIS AFTERNOON IN THE WEST
PARTS OF THE CWA. HOWEVER SOME WEAK ASCENT IS PREDICTED OVER THE
PLAINS WHICH MAY HELP THINGS OUT A BIT THERE. INDEED THE LATEST
HRRR SUGGESTS MORE ACTIVITY OVER PLAINS THAN THE MOUNTAINS LATER
THIS AFTERNOON. WILL SEE IF THIS TREND CONTINUES IN LATER RUNS AND
PERHAPS ADJUST POPS ACCORDINGLY.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 238 AM MDT WED AUG 20 2014

SW FLOW ALOFT WILL BE OVER THE AREA TODAY AND TONIGHT WITH STILL
SOME MONSOON MOISTURE AFFECTING THE AREA.  PRECIPITABLE WATER VALUES
BY AFTN WILL BE AOA AN INCH OVER NERN CO WITH LOWER VALUES OVER THE
MTNS.  OVERALL WILL KEEP SCT TSTMS IN THE MTNS WITH WIDELY SCT
ACTIVITY ACROSS THE REST OF THE AREA.  CAPES WILL ONLY BE IN THE 500-
1000 J/KG SO THREAT OF SVR IS LOW HOWEVER MAY SEEM A FEW SPOTS
RECEIVE HEAVIER RAINFALL OVER THE PLAINS WHERE PRECIPITABLE WATER
VALUES WILL BE THE HIGHEST ALTHOUGH STORMS WILL BE MOVING RATHER
QUICKLY. AS FOR HIGHS WILL KEEP READINGS MAINLY IN THE UPPER 80S
TO LOWER 90S ACROSS NERN CO.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 1200 AM MDT WED AUG 20 2014

THURSDAY AND THURSDAY NIGHT...A PERSISTENT SOUTHWESTERLY FLOW
ALOFT WILL BE OVER THE STATE WITH AN UPPER TROUGH OVER THE GREAT
BASIN AND A RIDGE OF HIGH PRESSURE OVER THE SERN U.S. SUBTROPICAL
MOISTURE IS NOT AS WELL ESTABLISHED OVER CO WITH THE BEST CHC OF
TSTMS EXPECTED OVER THE HIGHER TERRAIN IN THE AFTN/EVNG...WITH
LESSER POPS OVER THE NERN PLAINS. NAM12 SOUNDINGS AT DENVER
INDICATE PW VALUES AROUND .6 TO .7 INCHES WITH STORM MOTIONS
AROUND 15 MPH. MAIN THREAT FM THE STORMS WILL CONTINUE TO BE BRIEF
HEAVY RAIN...BUT OVERALL FLOODING THREAT WILL BE IN THE LOW TO
MODERATE RANGE.

FRIDAY AND FRIDAY...THE GFS TRIES TO LIFT THE TROUGH FM THE GREAT
BASIN INTO CO...WHILE THE ECMWF AND NAM12 HOLD THE SYSTEM BACK.
THE PLUME OF SUBTROPICAL MOISTURE APPEARS TO BE BETTER ESTABLISHED
OVER NERN CO. NAM12 SOUNDINGS ON FRIDAY INCREASE THE PW VALUES
BACK TO AROUND ONE INCH...SO THE STORMS THAT DEVELOP SHUD PRODUCE
HEAVIER RAIN SHOWERS AND INCREASE THE POTENTIAL FOR FLOODING. THE
OVERALL STORM MOTIONS HOWEVER WILL BE FASTER (20-25 MPH). AS A
RESULT THE FLASH FLOOD RISK MAY NOT CHANGE MUCH FM THURSDAY.
OVERALL THE COVERAGE AND INTENSITY OF THE STORMS SHOULD INCREASE
...ASSUMING THE INCREASING CLOUD COVER DOES NOT OFFSET THE HEATING
TOO MUCH.

ON SATURDAY AND SATURDAY NIGHT...THE FLOW ALOFT REMAIN
SOUTHWESTERLY WITH THE MDLS DROPPING ANOTHER TROUGH FM THE
PACIFIC NORTHWEST ANDS INTO CENTRAL AND SRN IDAHO BY 12Z
SATURDAY. THE MDLS THEN DRAG THE TROUGH AXIS ACROSS
MONTANA/WYOMING LATE SATURDAY AND SATURDAY NIGHT. SHOULD AGAIN SEE
A DECENT COVERAGE FOR THUNDERSTORMS ESPECIALLY NORTH OF I-70 TO
THE CO/WY LINE SATURDAY NIGHT. WL INCREASE THE POPS IN THOSE AREAS
IN THE GRIDS.

SUNDAY AND SUNDAY NIGHT...A COLD FRONT ASSOCIATED WITH THE TROUGH
SHIFTING TO THE NORTH AND EAST OF COLORADO WILL PUSH THROUGH THE
CWFA BY SUNDAY MORNING. THE COOLER AMS SHOULD HELP CAP MUCH OF THE
DEEP CONVECTION OVER THE NERN PLAINS WITH THE BEST CHC OF TSTMS
OVER THE MOUNTAINS AND PALMER DIVIDE SUNDAY AFTN AND EVENING.

MONDAY THROUGH TUESDAY...THE MDLS SOLUTIONS CONTINUE TO DIFFER SO
HARD TO SETTLE ON ONE SOLUTION WITH THE SYNOPTIC SCALE FEATURES
COMPLETELY OUT OF PHASE WITH ONE ANOTHER OVER THE WRN U.S. FOR
NOW THE OVERALL TREND WL BE TO KEEP A CHANCE OF TSTMS IN THE
MOUNTAINS WITH LESSER POPS OVER THE NORTHEASTERN PLAINS EACH
AFTN/EVNG.

&&

.AVIATION...(FOR THE TAFS THROUGH 18Z THURSDAY MORNING)
ISSUED AT 936 AM MDT WED AUG 20 2014

WENT WITH TEMPO TS IN THE DENVER TAF AT 15Z BASED MAINLY ON HRRR
OUTPUT. CURRENT TIMING FOR THUNDER IN THE TAFS SEEMS REASONABLE.
LITTLE ELSE OF CONCERN AS WINDS SHOULD BE RELATIVELY LIGHT ASIDE
FROM THUNDERSTORM OUTFLOWS.

&&

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

&&

$$

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



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.