848  
FXUS65 KBOU 231029  
AFDBOU  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DENVER/BOULDER CO  
429 AM MDT MON APR 23 2018  
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 429 AM MDT MON APR 23 2018  
 
MODELS ARE TRENDING TOWARD A BIT MORE DISORGANIZED SYSTEM OVER THE  
NEXT 36 HOURS. THE BEST LIFT WILL MOVE ACROSS WYOMING TODAY,  
WEAKENING AS THE TAIL END OF THE TROUGH DRAGS ACROSS COLORADO  
TONIGHT AND EARLY TUESDAY. AS SO OFTEN HAPPENS, THE LIFT OVER US  
WILL BE WORKING ON RELATIVELY DRY AIR, WITH SOME LOW/MID LEVEL  
MOISTURE ALONG THE FRONTAL BAND. THIS MEANS THE BEST WINDOW OF  
SATURATED/SLIGHTLY UNSTABLE AIR WITH SOME QG LIFT WILL BE A FEW  
HOURS DURING THE NIGHT, A FEW HOURS SLOWER THAN PREVIOUSLY  
FORECAST.  
 
FOR TODAY THERE WILL BE A LITTLE INSTABILITY OVER THE MOUNTAINS  
THAT SHOULD GENERATE SOME SHOWERS/STORMS. EAST OF THE MOUNTAINS  
THE LOW LEVELS WILL BE A BIT TOO DRY TO ENCOURAGE THE CONVECTION,  
SO WE'LL MAINLY SEE WHATEVER HAPPENS OVER THE MOUNTAINS DRIFTING  
EAST IN THE LATE AFTERNOON/EARLY EVENING. FURTHER EAST ON THE  
PLAINS IT WILL BE A LITTLE COOLER BUT THERE WILL BE SOME MOISTURE,  
PERHAPS ENOUGH TO ALLOW SHOWERS TO CONTINUE TO PROPAGATE EAST IN  
THE EVENING.  
 
THE MAIN EVENT WILL BE THE FRONTAL BAND. LOW LEVEL COLD FRONT WILL  
PROBABLY RUSH AHEAD OF THE UPPER FEATURE IN THE EVENING WITH SHARP  
COOLING AND GUSTY NORTH WINDS ON THE PLAINS DURING THE MIDDLE OF  
THE NIGHT. DEEPER SHOWER ACTIVITY IS PROBABLY MORE TOWARD THE  
LATER PART OF THE NIGHT. STILL LOOKING FOR SHARP ENOUGH COOLING TO  
GIVE A CHANCE OF SNOW BY SUNRISE OVER MUCH OF THE PLAINS, THOUGH  
AIR TEMPERATURES WILL BE NEAR FREEZING AND EVERYTHING ELSE WILL  
BE WARM SO THE IMPACT WILL BE VERY LIMITED. SOME HIGH MOUNTAIN  
AREAS WILL PICK UP SEVERAL INCHES OF SNOW, BUT AGAIN TEMPERATURES  
WILL LIMIT THE IMPACT TO THE HIGHER MOUNTAIN AREAS.  
   
LONG TERM
 
(TUESDAY THROUGH SUNDAY)  
ISSUED AT 429 AM MDT MON APR 23 2018  
 
IT WILL BE COLD TUESDAY MORNING BEHIND TONIGHT'S COLD FRONT. AN  
UPPER LEVEL TROUGH OVER WYOMING WILL PRODUCE LIFT ACROSS FAR EASTERN  
COLORADO AND INTO THE CENTRAL PLAINS EARLY TUESDAY. THE UPPER LEVEL  
TROUGH AND BEST LIFT WILL SHIFT EASTWARD THROUGH TUESDAY. NORTHEAST  
UPSLOPE FLOW ALONG THE FRONT RANGE WILL ALSO PRODUCE LOW LEVEL LIFT  
RESULTING IN LOW CLOUDS, SNOW, AND POSSIBLY DRIZZLE/FREEZING DRIZZLE  
TUESDAY MORNING. GIVEN THE WARM GROUND TEMPERATURES ANY ICE  
ACCUMULATION WILL OCCUR ON ELEVATED SURFACES. UP TO 3 INCHES OF  
SNOW WILL BE POSSIBLE IN THE FOOTHILLS AND MOUNTAINS. DUE TO THE  
CLOUD COVER AND COLD AIRMASS, HIGHS ARE EXPECTED TO BE IN THE 40S  
ACROSS NORTHEAST COLORADO. SURFACE HIGH PRESSURE WILL SETTLE OVER  
COLORADO TUESDAY NIGHT BRINGING CLEARING SKIES, CHILLY  
TEMPERATURES, AND POSSIBLY FOG.  
 
RIDGING IN THE NORTHWEST FLOW ALOFT WILL BRING MILD AND DRY  
CONDITIONS FOR WEDNESDAY. THE NEXT TROUGH WILL DROP SOUTHEAST ACROSS  
THE REGION THURSDAY. THE COLD FRONT ASSOCIATED WITH THIS SYSTEM WILL  
PUSH SOUTH THROUGH COLORADO LATE WEDNESDAY NIGHT AND EARLY THURSDAY.  
THIS SYSTEM IS WEAKER THAN TONIGHT'S/TUESDAY'S SYSTEM. COOLER  
TEMPERATURES WILL PREVAIL THURSDAY. WILL HAVE LOW POPS FOR THIS  
SYSTEM AS WELL. IF ANY PRECIPITATION OCCURS, IT WILL BE LIGHT.  
 
FOR FRIDAY AND NEXT WEEKEND, UPPER LEVEL RIDGE MOVES ACROSS COLORADO  
FRIDAY AND THEN SHIFTS OVER THE CENTRAL PART OF THE COUNTY FOR THE  
WEEKEND. TEMPERATURES WILL BE MILD UNDER THIS PATTERN AND WARM WELL  
INTO THE 70S THIS WEEKEND AS SOUTHWEST FLOW ALOFT PREVAILS BEHIND  
THE RIDGE. MODELS SHOW A SHORT WAVE TROUGH EMBEDDED IN THE SOUTHWEST  
FLOW FOR THIS WEEKEND. HOWEVER, QUITE A BIT OF UNCERTAINTY ON THE  
TIMING, PLACEMENT, AND THE AMOUNT OF MOISTURE AND INSTABILITY. THIS  
SYSTEM COULD BRING A ROUND OF SHOWERS AND THUNDERSTORMS WITH IT.  
WILL HAVE LOW POPS IN THE FORECAST FOR THIS SYSTEM WITH THE HIGHEST  
POPS OVER THE MOUNTAINS.  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)  
ISSUED AT 429 AM MDT MON APR 23 2018  
 
VFR TODAY, WITH ISOLATED THUNDERSTORMS BY LATE AFTERNOON THAT  
COULD PRODUCE GUSTS TO 30 KNOTS. A COLD FRONT IS EXPECTED TO PASS  
BETWEEN 02Z AND 06Z, FOLLOWED BY NORTH WINDS GUSTING TO 30 KNOTS.  
MVFR CONDITIONS IN RAIN AND SNOW SHOWERS WILL LIKELY DEVELOP A  
COUPLE OF HOURS LATER AND CONTINUE INTO TUESDAY MORNING. LITTLE OR  
NO SNOW ACCUMULATION IS EXPECTED IN THE DENVER AREA.  
 

 
   
BOU WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
SHORT TERM...GIMMESTAD  
LONG TERM...MEIER  
AVIATION...GIMMESTAD  
 
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