Issued by NWS Denver/Boulder, CO
000 FXUS65 KBOU 200812 AFDBOU AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 215 AM MDT SAT SEP 20 2008 .SHORT TERM...LEAD SHORTWAVE AHEAD OF THE WEST COAST TROUGH WILL LIFT NORTHEAST THROUGH TONIGHT. DEFORMATION ZONE AHEAD OF THIS FEATURE WILL SPREAD OVER NORTHEASTERN COLORADO BY TONIGHT. MOISTURE REMAINS MAINLY ABOVE 500 MB...BUT THERE WILL BE SOME WEAK WARM ADVECTION IN A NEUTRAL ENVIRONMENT ESPECIALLY THIS EVENING. THIS SHOULD PROMOTE THE DEVELOPMENT OF A PRETTY SUBSTANTIAL MID/HIGH CLOUD DECK AND LIGHT SHOWERS. LOW LEVEL WINDS WILL BE SE VEERING TO SW WHICH SHOULD MAINTAIN THE DRY LAYER NEAR THE SURFACE. THE CURRENT FORECAST POPS LOOK FINE AS THE BEST LIFT LOOKS TO PASS NORTH OF OUR AREA. TRIMMED HIGHS OVER THE WESTERN PART OF THE FORECAST AREA TODAY FOR EXPECTED CLOUD DEVELOPMENT...AND RAISED LOWS TONIGHT FOR THE SAME REASON. .LONG TERM...ON SUNDAY...THE MDLS STILL BRING THE FIRST OF TWO UPPER TROFS ACROSS THE CWFA. WEAK QG ASCENT IS INDICATED AOA 700 MB WITH STRONGER DOWNWARD VELOCITIES AT THE SFC. ALL THE MDLS ARE FAIRLY CONSISTENT WITH THE MOVEMENT AND STRENGTH OF THE SYSTEM. NAM INTERACTIVE SOUNDINGS INDICATE CAPES OF 500-800 J/KG AT DEN AND LIMON WITH CAPES AROUND 1400 J/KG IN THE NERN CORNER OF THE STATE. CURRENT GRIDS HAVE 20 POPS IN THE FCST AND SEE NO REASON TO CHANGE MUCH AT THIS TIME. THE NEXT SYSTEM IS PROGGED TO MOVE ACRS NRN CO ON MONDAY. THE QG ASCENT IS STRONGER WITH THIS SECOND SYSTEM AOA 700 MB...BUT DOWNSLOPE AT THE SFC KEEPS THE LOWER LEVELS DRIER AND SUBSIDENT. FOR THIS REASON WL CONTINUE WITH SLGT CHC POPS ON MONDAY. THE MDLS DO INDICATE STG DOWNWARD DESCENT AT ALL LEVELS FOR MONDAY NIGHT INTO TUESDAY. NOT MUCH QPF GENERATED BY THE MDLS ON TUESDAY SO THE PROSPECT OF TSTMS IS NOT VERY GOOD. WL KEEP SOME TOKEN 10 PERCENT POPS IN FOR TUESDAY BUT THATS IT. FOR THE RMNDR OF THE WEEK AN UPPER LEVEL RIDGE WL BE OVER THE SRN/CNTRL U.S. WITH NO APPARENT MSTR IN SITE. A WEAK SYSTEM MAY BRING SOME SLGHTLY COOLER TEMPERATURES TO THE REGION TOWARDS THE END OF THE WEAK AS IT PASSES TO THE NORTH OF THE STATE. THIS ALREADY REFLECTED IN THE GRIDS SO NO CHANGES PLANNED BEYOND TUESDAY. && .AVIATION...ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON WITH THE MOST LIKELY TIME FOR SHOWERS IN THE DENVER AREA THIS EVENING. THERE IS A 20 PERCENT CHANCE OF ENOUGH SHOWER ACTIVITY TO LOWER CEILINGS BELOW 5000 FEET FOR A FEW HOURS TONIGHT. && .BOU WATCHES/WARNINGS/ADVISORIES...NONE. $$ GIMMESTAD/COOPER
