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

000
FXUS65 KBOU 231616
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
1016 AM MDT SAT APR 23 2016

.UPDATE...
ISSUED AT 1013 AM MDT SAT APR 23 2016

STRONG WINDS ALREADY DEVELOPING ABOVE TIMBERLINE THIS MORNING SO
HAVE UPDATED TO GRIDS TO ACCOUNT FOR STRONGER GUSTS IN THE
MOUNTAINS TODAY. MOSTLY CLOUDY ACROSS MUCH OF THE URBAN CORRIDOR
AND NORTHEAST PLAINS TODAY TOO. AS A RESULT...I SHAVED A DEGREE
OR TWO OF THE MAX TEMPERATURES BUT STILL QUITE MILD.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM MDT SAT APR 23 2016

SOUTHWEST WINDS ALOFT WILL BE INCREASING TODAY AHEAD OF AN
APPROACHING UPPER TROUGH THAT IS OVER WESTERN UTAH THIS MORNING.
AS DAYTIME WARMING INCREASES THE DEPTH OF THE BOUNDARY LAYER...THE
WINDS ALOFT ARE EXPECTED TO MIX DOWN TO THE SURFACE...BRINGING
GUSTY WINDS TO THE PLAINS THROUGH THE AFTERNOON. THE LATEST RUNS
OF THE HRRR MODEL HAVE BEEN SHOWING A CONSOLIDATED BAND OF SHOWERS
ASSOCIATED WITH THE TROUGH AXIS MOVING OVER THE MOUNTAINS AFTER
22Z. LIGHTNING HAS BEEN DETECTED THIS MORNING OVER
UTAH...INDICATING THE INSTABILITY OF THE AIRMASS THAT WILL
ACCOMPANY THE UPPER TROUGH AS IT MOVES ACROSS THE STATE. MODEL
SOUNDINGS SHOW THAT FREEZING LEVELS WILL BE AROUND 12000 FEET MSL
AHEAD OF THE TROUGH...SO THE MOUNTAINS WILL SEE A MIX OF RAIN AND
SNOW WITH THE AFTERNOON SHOWERS...WITH THE SNOW LEVELS DROPPING
LATER IN THE EVENING. MODEL SOUNDINGS ALSO SHOW THE AIRMASS WILL
BE QUITE DRY ON THE PLAINS...MAKING IT TOUGH FOR ANY RAIN TO
REACH THE GROUND ON THE PLAINS. HOWEVER...GUSTY WINDS ARE EXPECTED
THROUGH THE LATE AFTERNOON AND EVENING DUE TO DOWNBURSTS FROM
VIRGA SHOWERS AND THE SOUTHWEST FLOW AT MID-LEVELS BEING MIXED
DOWN TO THE SURFACE. AS THE UPPER TROUGH MOVES EASTWARD AND ONTO
THE PLAINS...SHOWER ACTIVITY OVER THE MOUNTAINS AND PLAINS WILL BE
DECREASING BY MIDNIGHT. TEMPERATURES WILL ALSO COOL DOWN LATER
TONIGHT AS THE POST-TROUGH AIRMASS MOVES IN.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 412 AM MDT SAT APR 23 2016

AN UPPER LEVEL STORM SYSTEM WILL BE CENTERED OVER ERN WY EARLY ON
SUN AND THEN WILL MOVE SLOWLY EAST INTO SCNTRL SOUTH DAKOTA AND
NCNTRL NEBRASKA BY EARLY SUN EVENING.  COMBINATION OF RATHER STG SFC
GRADIENT AND QG DOWNWARD DESCENT WILL ALLOW FOR STG WINDS IN THE
MORNING ESPECIALLY ACROSS THE NRN FOOTHILLS AND HIGHER MTNS.  WOULD
NOT BE SURPRISED TO SEE A SOME SPOTS RECEIVE HIGH WIND CRITERIA
FOR A FEW HOURS. MEANWHILE GUSTY WINDS WILL ALSO OCCUR OVER THE
PLAINS BUT SPEEDS SHOULD STAY BLO HIGH WIND CRITERIA.

AS FAR AS PCPN CROSS-SECTIONS CONTINUE TO SHOW FAVORABLE OROGRAPHICS
AND LINGERING MOISTURE IN THE NRN MTNS MAINLY NR THE WY BORDER WITH
ADVISORY AMOUNTS POSSIBLE IN ZN 31.  OTHERWISE MAY SEE A FEW AFTN
SHOWERS ACROSS THE PLAINS NEAR THE WY-NE BORDER.  AS FOR HIGHS
READINGS WILL DROP BACK INTO THE 65 TO 70 DEGREE RANGE ACROSS NERN
CO.

BY MON THE FLOW ALOFT WILL BECOME SWLY AS ANOTHER STORM SYSTEM
MOVES INTO THE GREAT BASIN. MEANWHILE SFC LOW PRES WILL INTENSIFY
ALONG THE FOOTHILLS WITH GUSTY SSE WINDS ACROSS THE PLAINS BY
AFTN. AS FOR PCPN POTENTIAL...MOISTURE WILL INCREASE BY AFTN IN
THE MTNS AND COMBINE WITH FAVORABLE LAPSE RATES FOR SOME SCT
SHOWERS AND POSSIBLE A FEW TSTMS. OVER NERN CO IT WILL BE DRY
ALTHOUGH THERE COULD BEA FEW LATE AFTN HIGH BASED STORMS ALONG THE
FRONT RANGE. AS FOR HIGHS READINGS WILL BE IN THE MID 60S TO LOWER
70S ACROSS THE PLAINS.

FOR MON NIGHT THRU TUE ONCE AGAIN ITS NOT CLEAR HOW THE UPPER LEVEL
STORM SYSTEM WILL EVOLVE. IT APPEARS ONCE PIECE OF ENERGY MAY
MOVE NNE INTO THE NRN ROCKIES WHILE SIGNIFICANT ENERGY REFORMS
INTO A CLOSED LOW NEAR THE FOUR CORNERS AREA BY TUE. MEANWHILE
THE MAIN SFC LOW MAY INTENSIFY OVER SERN CO WITH DEEPER LOW LVL
MOISTURE ADVECTING INTO NERN CO NORTH OF A WRM FNT. OVERALL SHOULD
SEE A CHC OF SHOWERS AND TSTMS ESPECIALLY ACROSS THE PLAINS MON
NIGHT. ON TUE BEST CHC OF SHOWERS AND TSTMS WILL BE IN THE AFTN
ACROSS THE AREA. THERE ALSO COULD BE SOME THREAT OF STRONGER
STORMS ACROSS PORTIONS OF THE PLAINS TUE AFTN NEAR THE TRIPLE
POINT AND JUST NORTH OF THE WRM FRONT.

BY TUE NIGHT INTO WED THERE IS SOME POTENTIAL THAT THE UPPER LEVEL
LOW NEAR THE FOUR CORNERS WILL INTENSIFY AND MOVE INTO SERN CO BY
12Z WED AND THEN LIFT NORTHEAST INTO NWRN KANSAS/SWRN NEBRASKA BY
WED AFTN.  IF THIS OCCURS THEN THERE COULD BE SOME SIGNIFICANT PCPN
TUE NIGHT INTO WED ACROSS PORTIONS OF NRN CO.  BUFFER SOUNDINGS SHOW
TEMPS WILL BE WRM ENOUGH FOR PCPN TO FALL MOSTLY AS RAIN ACROSS THE
PLAINS WITH THE SNOW LEVEL ABOVE 6000 FT.

FOR WED NIGHT INTO THU THE UPPER LEVEL LOW IS FCST TO MOVE ENE OF
THE AREA AS ANOTHER SYSTEM DIVES INTO SRN CALIFORNIA.  THUS SHOULD
SEE DRIER CONDITIONS WED NIGHT INTO THU.  HOWEVER LINGERING MOISTURE
COMBINED WITH AFTN HEATING MAY LEAD TO A SLIGHT CHC OF SHOWERS AND
TSTMS ACROSS THE HIGHER TERRAIN AND ALONG THE FRONT RANGE.

BY FRI THE ECMWF AND GFS WANT TO EJECT THE LOW FM SRN CALIFORNIA
INTO THE FOUR CORNERS AREA BY FRI AFTN WHILE THE CANADIAN MODEL IS
CONSIDERABLY SLOWER AND FUTHER SW.  THIS FAR OUT HARD TO SAY WHAT
WILL HAPPEN WITH THIS NEXT FEATURE.  FOR NOW WILL JUST GO WITH CHC
POPS IN THE MTNS WITH A SLIGHT CHC OVER THE PLAINS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1013 AM MDT SAT APR 23 2016

VFR CONDITIONS EXPECTED. SOUTH TO SOUTHWEST WINDS WILL BE
INCREASING THROUGH THIS AFTERNOON AS A SURFACE TROUGH DEEPENS OVER
THE EASTERN PLAINS. GUSTS UP TO 30 MPH CAN BE EXPECTED BY LATE
THIS AFTERNOON. CONVECTION IS EXPECTED OVER THE FOOTHILLS THIS
AFTERNOON WHICH COULD MOVE OUT OVER THE URBAN CORRIDOR DURING THE
EVENING AS THE MAIN UPPER TROUGH PROGRESSES EASTWARD. GUSTY WINDS
BUT LITTLE PRECIPITATION IS EXPECTED FROM THE HIGH BASED SHOWERS.
GUSTS 40-50 MPH WILL BE POSSIBLE WITH THE EARLY EVENING SHOWER
ACTIVITY.

&&

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

$$

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



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