Issued by NWS Denver/Boulder, CO
000 FXUS65 KBOU 242028 AFDBOU AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 228 PM MDT FRI OCT 25 2008 .SHORT TERM...MID LEVEL SHORTWAVE HAS PASSED AREA...AS NOTED BY WATER VAPOR LOOPS. STILL SOME MID LEVEL MOISTURE ACROSS PLAINS...BUT FOR THE MOST PART...SKIES HAVE CLEARED. SOME GUSTY WINDS CONTINUE ACROSS MOUNTAINS AND ALONG HIGHER FOOTHILLS...WITH A FEW GUSTS REACHING 50 MPH ON NIWOT RIDGE. ACROSS PLAINS...AIRMASS WARMED ENOUGH TO PROVIDE SOME MIXING...WITH GUSTY NORTHWESTERLIES IN THE 10-20KT RANGE. WEAK ANTICYCLONE DEVELOPED NEAR DENVER...WHICH SHIFTED WINDS TO THE NORTHEAST AT LOCAL AIRPORTS. MODELS SHOW AIRMASS STABILIZING DURING THE EVENING WITH LOWER LEVELS OF ATMOSPHERE DECOUPLING. SO...WINDS ACROSS PLAINS SHOULD BEGIN TO DECREASE AFTER SUNSET AND BECOME DIURNAL. OVER THE HIGHER ELEVATIONS...WINDS TO REMAIN GUSTY THROUGH THE OVERNIGHT AS CROSS MOUNTAIN WIND COMPONENT AVERAGES AROUND 30 KTS. NEXT SHORTWAVE SHOWING UP ON WATER VAPOR ACROSS IDAHO AND WESTERN MONTANA...PROGGED TO MOVE ACROSS COLORADO AFTER 12Z. LATEST NAM SHOWING CROSS MOUNTAIN WINDS INCREASE TO 45 KTS BY 18Z WITH FORECAST SOUNDINGS AND CROSS SECTIONS INDICATING A BIT OF A MOUNTAIN TOP STABLE LAYER. COULD SHOULD SEE SOME GUSTS INCREASING TO AROUND 60 MPH ACROSS THE HIGHER EXPOSED RIDGES. ACROSS PLAINS...THERE SHOULD BE ENOUGH MIXING IN THE LOWER LEVELS BY AFTERNOON WITH NORTHWESTERLIES REACHING THE SURFACE. LATEST NAM SHOWING SPEEDS IN THE 10-20 KT RANGE. CROSS SECTIONS SHOW A GRADUAL INCREASE IN MID AND HIGH LEVEL MOISTURE THROUGH THE DAY. COULD SEE SOME WAVE CLOUDS DEVELOP ALONG FRONT RANGE DURING THE AFTERNOON. TEMPERATURE AND THICKNESS PROGS AS WELL AS GUIDANCE SHOWS HIGHS REACHING 70 DEGREES ACROSS THE PLAINS. THE AMOUNT OF CLOUD COVER COULD LIMIT THE WARMING...BUT FEEL THAT THE DOWNSLOPE WARMING SHOULD OFFSET CLOUD COVER. CURRENT TEMPERATURE GRIDS IN LINE WITH GUIDANCE AND SEEMS REASONABLE...NO CHANGES NEEDED AT THIS TIME. .LONG TERM...MODELS HAVE PRETTY DECENT NORTHWESTERLY FLOW ALOFT FOR THE FORECAST AREA SATURDAY NIGHT AND SUNDAY. BY SUNDAY NIGHT CONTINUING THROUGH MONDAY NIGHT...THE NORTHWESTERLY FLOW DECREASES AS AN UPPER RIDGE MOVES SLOWLY EASTWARD FROM THE SOUTHWESTERN UNITED STATES. THE QG VERTICAL VELOCITY FIELDS HAVE BENIGN SYNOPTIC SCALE MOTIONS PROGGED THROUGH ALL THE PERIOD. THE LOW LEVEL PRESSURE AND WIND FIELDS ARE STILL BRINGING A SURGE OF HIGH PRESSURE AND COOLER AIR INTO THE FORECAST AREA SOMETIME ON SUNDAY. THE NAM AND GFS ARE STILL AT ODDS ABOUT TIMING...BUT BOTH SHOW THE NEW COLDER AIRMASS TO BE NOT ALL THAT SIGNIFICANT. THE DECENT COLD AIR IS WELL TO OUR NORTHEAST AND EAST. THE BOUNDARY LAYER FLOW IS MAINLY NORTHWESTERLY SATURDAY NIGHT. AGAIN THE NAM HAS UPSLOPE FOR MUCH OF SUNDAY INTO THE EVENING...THE GFS HAS IT BY MID AFTERNOON INTO THE EVENING. LOOKING AT MOISTURE...THERE IS A BIT OF MID AND UPPER LEVEL MOISTURE ON BOTH MODELS FOR SATURDAY NIGHT. NOW THE MODELS HAVE MINIMAL MOISTURE OVER US ON SUNDAY. THERE IS SOME IN THE LOWER AND MID LEVELS SUNDAY EVENING. BY MONDAY MORNING...CONTINUING INTO THE EXTENDED PERIOD...MOISTURE IS QUITE SPARSE. AGAIN...NO POPS FOR THIS PACKAGE FROM SATURDAY NIGHT THROUGH MONDAY NIGHT. FOR TEMPERATURES...SUNDAY`S HIGHS ARE SIMILAR TO SATURDAY`S...WITH 2-4 C COOLER OVER THE NORTHEAST CORNER. MONDAY`S READINGS LOOK 0-1.2 C WARMER THAN SUNDAY`S. FOR THE LATER DAYS...TUESDAY THROUGH FRIDAY...AN UPPER RIDGE IS PROGGED OVER THE FORECAST AREA THROUGH THURSDAY...WITH SOUTHWESTERLY FLOW ALOFT ON FRIDAY AFTER THE RIDGE AXIS MOVES EAST. IT IS DRY. TEMPERATURES ARE ABOVE SEASONAL NORMALS. && .AVIATION...VFR CONDITIONS TO CONTINUE THROUGH FRIDAY. SFC WINDS HVE BECOME NORTHERLY ACROSS THE LOCAL AREA WITH SPEEDS IN THE 10-20 KT RANGE. WINDS TO DECREASE BY 03Z AND BECOME DIURNAL ONCE AIRMASS STABILIZES. ON FRIDAY...MID LEVEL MOISTURE TO MOVE ACROSS AREA BY 18Z. WINDS TO BECOME NORTHWESTERLY AT AREA AIRPORTS BY 18Z WITH SPEEDS IN THE 10-20KT RANGE. && .BOU WATCHES/WARNINGS/ADVISORIES...NONE. $$ D_L/RJK
