FXUS65 KBOU 252135
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
235 PM MST WED NOV 25 2009

.SHORT TERM...MODELS HAVE THE STRONG NORTHERLY FLOW ALOFT DECREASING 
GRADUALLY OVERNIGHT AND BECOMING MORE NORTHWESTERLY.  ON THURSDAY 
...THE UPPER RIDGE GETS OVER COLORADO.  THE FLOW ALOFT FOR THE 
FORECAST AREA IS WEAK NORTHWESTERLY THROUGH THE DAY.  VERY WEAK 
DOWNWARD TO NO VERTICAL VELOCITY IS PROGGED FOR THE FORECAST AREA 
TONIGHT AND THURSDAY.  THE LOW LEVEL PRESSURE AND WIND FIELDS POINT 
TO A WEAK GRADIENT THIS EVENING WITH NORMAL DIURNAL TRENDS EXPECTED 
IN THE BOUNDARY LAYER FLOW.  AFTER MIDNIGHT AND CONTINUING ON 
THURSDAY...TROUGHING EAST OF THE MOUNTAINS POINTS TO A BIT OF 
DOWNSLOPING INFLUENCE TO THE NORMAL WIND REGIME.   CONCERNING 
MOISTURE...MODELS HAVE SOME OVER THE EASTERN THIRD OF THE FORECAST 
AREA THIS EVENING...THEN ITS VERY DRY THROUGH THURSDAY.  THERE IS 
NOTHING ON THE QPF FIELDS.  NO POPS.  FOR TEMPERATURES...THICKNESS 
GRIDS SHOW WARMING WITH THE UPPER RIDGE MOVING IN.  THURSDAY HIGHS 
LOOK 4-6 C WARMER THAN THIS AFTERNOON'S HIGHS.   

.LONG TERM...ONE MORE WARM AND DRY DAY IN STORE ON FRIDAY WITH A 
THERMAL RIDGE OVERHEAD AND WESTERLY WINDS GIVING US A DOWNSLOPE 
COMPONENT.  COLD ADVECTION WILL BEGIN LATER SATURDAY AS A SURFACE 
HIGH BEGINS TO DROP ACROSS THE AREA.  THE UPPER TROUGH SWEEPS 
SOUTHEAST ON SUNDAY.  BOTH GFS AND ECMWF SHOW A BRIEF PERIOD OF DEEP 
MOIST UPSLOPE SATURDAY NIGHT ALONG WITH SOME WEAK UPPER LIFT...GFS 
ACTUALLY SHOWS SEVERAL INCHES OF SNOW OVER ZONES 36 AND 41. FOR NOW 
WILL RAISE POPS FOR METRO DENVER AND PALMER DIVIDE...THIS WILL NOT 
BE A LONG PERIOD OF UPSLOPE...BUT MEASURABLE SNOW IS NOW LOOKING 
MORE PROBABLE.  SNOW IS EXPECTED TO END NORTH TO SOUTH LATE SUNDAY 
AND SUNDAY NIGHT...WITH CONTINUED COOL TEMPERATURES.  TUESDAY WE 
WILL SEE PREFRONTAL WARMING...WITH ANOTHER TROUGH EXPECTED TO SURGE 
SOUTHWARD TUESDAY NIGHT BRINGING MUCH COOLER AIR AND ANOTHER PERIOD 
OF UPSLOPE SNOW.  HAVE PUT IN SCT POPS FOR TUESDAY NIGHT WITH THIS 
SYSTEM...AGAIN CONCENTRATING ON MOUNTAINS...SOUTHERN FOOTHILLS...AND 
PALMER DIVIDE.  

&&

.AVIATION...SKIES WILL BE MOSTLY CLEAR THIS EVENING...THEN CLEAR 
THROUGH THURSDAY.  WEAK SURFACE WINDS ARE EXPECTED FOR A COUPLE 
HOURS AFTER SUNSET...THEN NORMAL DRAINAGE WINDS ARE EXPECTED INTO 
THURSDAY MORNING.  THURSDAY'S WINDS WILL BE PRETTY WEAK ALL DAY.

&&

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

$$
RJK/RTG