401  
FXUS65 KBOU 242045  
AFDBOU  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DENVER/BOULDER CO  
245 PM MDT MON APR 24 2017  
   
SHORT TERM
 
(THIS EVENING THROUGH TUESDAY)  
ISSUED AT 221 PM MDT MON APR 24 2017  
 
FOR LATE AFTERNOON AND EARLY EVENING, AN EASTERLY UPSLOPE FLOW  
AND CONVERGENCE ALONG A BOUNDARY IS EXPECTED TO PRODUCE ISOLATED  
SHOWERS AND THUNDERSTORMS ALONG THE FRONT RANGE AND ACROSS THE  
EASTERN PLAINS. MOISTURE AND INSTABILITY IS LIMITED, SO THE  
SHOWERS AND STORMS ARE EXPECTED TO BE WEAK AND SHORT LIVED.  
 
GOES-16 WATER VAPOR SATELLITE IMAGERY SHOWING A SHORT WAVE TROUGH  
OVER NORTHERN NEVADA AND SOUTHERN IDAHO. IT IS PRODUCING  
WIDESPREAD PRECIPITATION AHEAD OF IT OVER SOUTHEAST IDAHO AND  
NORTHERN UTAH AT THIS TIME. AS IT PROGRESSES EASTWARD, IT WILL  
CLOSE OFF OVER WYOMING TONIGHT. THE PRECIPITATION IS EXPECTED TO  
SHIFT EASTWARD WITH THE SYSTEM TONIGHT. THIS SHOULD RESULT IN RAIN  
AND SNOW OVER THE HIGH COUNTY. SNOW LEVEL WILL BE AROUND 10000  
FEET MSL TO START OFF WITH AND LOWER THROUGH THE NIGHT. EXPECT THE  
HEAVIEST PRECIPITATION TO BE OVER NORTHERN COLORADO WHERE THE  
BEST LIFT WILL BE. MOIST WESTERLY FLOW AROUND THE BASE OF THE  
TROUGH WILL RESULT IN OROGRAPHIC LIFT OVER THE MOUNTAINS WHICH  
WILL ALSO HELP PRODUCE PRECIPITATION. IN ADDITION, THE LEFT EXIT  
REGION OF THE JET WILL BE OVER WYOMING AND NORTHERN COLORADO AND  
PROVIDE LIFT. THE JET SINKS SOUTH LATE TONIGHT AND WILL HELP  
PROVIDE LIFT OVER CENTRAL COLORADO. SNOW AMOUNTS FOR THE MOUNTAINS  
ARE EXPECTED TO BE 2 TO 6 INCHES OVERNIGHT. THE HIGHEST AMOUNTS  
ARE EXPECTED TO BE OVER THE NORTHERN MOUNTAINS.  
 
EXPECT A BRIEF BREAK IN PRECIPITATION OVER THE AREA TUESDAY  
MORNING. BY AFTERNOON, THE NEXT SHORT WAVE TROUGH DIGS SOUTHEAST  
AND WILL BE CENTERED OVER THE FOUR CORNERS. LIFT FROM THIS,  
COMBINED WITH INCREASING NORTH TO NORTHEAST WINDS ALONG THE FRONT  
RANGE, IS EXPECTED TO PRODUCE SCATTERED SHOWERS. BEST LIFT WILL BE  
SOUTH OF I- 70, SO WILL HAVE THE HIGHEST POPS HERE. CLOUD COVER  
AND A COOLER AIRMASS WILL RESULT IN COOLER HIGH TEMPERATURES WITH  
READINGS IN THE MID TO UPPER 50S.  
   
LONG TERM
 
(TUESDAY NIGHT THROUGH MONDAY)  
ISSUED AT 221 PM MDT MON APR 24 2017  
 
A SPLIT-ENERGY LOW WILL BE OVER THE STATE WITH THE UPPER LEVEL JET  
TO THE SOUTH OVER NM. QG ENERGY WILL INCREASE OVER THE SOUTHERN  
PORTIONS OF THE STATE TUESDAY NIGHT INTO WEDNESDAY HELPING TO FOCUS  
MUCH OF THE PRECIPITATION SOUTH OF I-25. WITH THE AID OF A NORTHERLY  
PUSH EARLIER IN THE DAY AND COOLER TEMPERATURES EXPECT RAIN TO  
CHANGE OVER TO SNOW WITH SNOW LEVELS STARTING AROUND 7000FT DROPPING  
DOWN TO 5000FT OVERNIGHT...HOWEVER THIS WILL OCCUR AS PRECIPITATION  
STARTS TO DIMINISH ON THE PLAINS. AT THIS TIME SNOWFALL AMOUNTS  
LOOK TO BE 2 TO 6 INCHES FOR THE MOUNTAINS AND A TRACE TO 3 INCHES  
ON THE PLAINS WITH THE HIGHER AMOUNTS OVER THE PALMER DIVIDE AND  
PORTIONS OF DOUGLAS AND LINCOLN COUNTIES BY WEDNESDAY MORNING.  
 
THE NEXT SYSTEM IN LINE TO IMPACT THE AREA WILL BE EMBEDDED IN NW  
FLOW ALOFT BY LATE WEDNESDAY INTO EARLY THURSDAY. MOISTURE WILL  
INCREASE AHEAD OF THE DISTURBANCE BRINGING SNOW TO THE MOUNTAINS  
LATE WEDNESDAY INTO THURSDAY MORNING. FOR THIS SYSTEM SNOWFALL  
AMOUNTS IN THE MOUNTAINS WILL RANGE FROM 4 TO 8 INCHES BY LATE  
THURSDAY. MODELS INDICATE SOME SHOWERS MAKING IT ONTO THE PLAINS BY  
THURSDAY AFTERNOON WITH LITTLE QPF FORECASTED. ANOTHER COLD PUSH  
WILL MOVE SOUTH BY LATE THURSDAY INTO EARLY FRIDAY.  
 
BY FRIDAY THE UPPER LOW WILL DIG FURTHER SOUTH INTO CO WITH THE  
MODELS SHOWING THE SYSTEM CUTTING OFF BY LATE FRIDAY OVER THE FOUR  
CORNERS REGION. THE CHANGEMAKER FOR THIS SYSTEM WILL BE THE MUCH  
COOLER 700 MB TEMPERATURES ALONG WITH THE INTRODUCTION OF INCREASED  
PACIFIC MOISTURE. THIS WILL HELP TO INCREASE CHANCES OF SNOW OVER  
THE PLAINS FOR FRIDAY INTO SATURDAY. MODELS ARE STILL IRONING OUT  
THE DETAILS BUT MODERATE RAIN AND SNOW ALONG WITH COOLER  
TEMPERATURES IS EXPECTED FOR THE REGION FRIDAY AND SATURDAY. THE  
COOLER TREND WILL START EARLIER IN THE WEEK WITH HIGHS ON THURSDAY IN  
THE MID TO UPPER 50S COOLING INTO THE 30S ON SATURDAY. WITH  
INCREASING SUBSIDENCE BEHIND THE MAIN BRANCH OF ENERGY SATURDAY  
CONDITIONS COULD CLEAR OUT DROPPING OVERNIGHT LOWS BELOW FREEZING.  
 

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)  
ISSUED AT 221 PM MDT MON APR 24 2017  
 
CLOUDS WILL CONTINUE TO INCREASE THIS AFTERNOON AS AN UPPER LEVEL  
SYSTEM MOVES INTO THE REGION. CEILINGS ARE EXPECTED TO REMAIN  
ABOVE 6000 FEET THROUGH 02Z. THERE WILL BE A SLIGHT CHANCE FOR A  
THUNDERSTORM THROUGH 03Z, ABOUT A 10 TO 20 PERCENT CHANCE, SO WILL  
NOT MENTION IN THE TAFS. CEILINGS WILL LOWER AROUND 00Z AND MAY  
END UP AROUND 6000 FEET FOR A SHORT TIME 02Z TO 08Z.  
 
THERE WILL BE SLIGHT CHANCE FOR LOW CLOUDS WITH CEILINGS LESS THAN  
1000 FEET AFTER 06Z. BEST CHANCE WILL BE OVER THE EASTERN COLORADO  
PLAINS AND EAST OF THE DENVER AREA. WILL MENTION FEW AT 1000 FEET  
FOR THE SLIGHT CHANCE OF LOW CEILINGS TONIGHT.  
 
WINDS ARE EXPECTED TO BE LIGHT THROUGH 18Z TUESDAY IN THE DENVER  
AREA. NORTHERLY WINDS WILL INCREASE AFTER 18Z AS HIGH PRESSURE  
INCREASES OVER WYOMING. THIS WILL BRING A BETTER CHANCE FOR RAIN  
SHOWERS TOWARDS 00Z WITH CEILINGS LOWERING TO AROUND 6000 FEET.  
THERE WILL BE A BETTER CHANCE FOR LOW CLOUDS LATE TUESDAY NIGHT  
AND WEDNESDAY MORNING.  
 

 
   
BOU WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
SHORT TERM...MEIER  
LONG TERM...BOWEN  
AVIATION...MEIER  
 
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