000
FXUS65 KBOU 081103
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
400 AM MST SUN NOV 8 2009

.SHORT TERM...THE RIGHT ENTRANCE REGION OF THE UPPER LEVEL JET IS 
PRESENTLY OVER NORTHWEST COLORADO AND EASTERN WYOMING...PRODUCING 
INCREASING CLOUDINESS OVER OUR FORECAST AREA.  AS THIS JET REMAINS 
IN THE VICINITY THROUGH THIS AFTERNOON...BROAD LIFT AND MOISTENING 
AT MID AND UPPER LEVELS WILL CONTINUE.  BY THIS EVENING WE SHOULD 
SEE SOME BANDED PRECIPITATION FALLING OVER THE MOUNTAINS AND 
NORTHERN PLAINS.  SOUNDINGS AND CROSS SECTIONS SHOW THAT THE LOWER 
LEVELS WILL REMAIN DRIER THAN AT MID LEVELS...SO LOW POPS ACROSS THE 
PLAINS SHOULD RESULT.  TEMPERATURES TODAY WILL BE MODERATED BACK 
TOWARDS CLIMATOLOGY DUE TO INCREASED CLOUD COVER AND PRESENCE OF A 
WEAK FRONTAL SURGE DROPPING OUT OF THE NORTH BY MID-AFTERNOON.  
PREVIOUS FORECAST PACKAGE LOOKED PRETTY GOOD...BUT I DID CUT POPS 
ACROSS THE PLAINS FROM 20 PERCENT DOWN TO 10 PERCENT.  

.LONG TERM...A WEAK UPPER LEVEL TROUGH WILL MOVE ACROSS THE AREA ON 
MON.  YESTERDAY THE GFS HAD MORE MOISTURE THAN THAN THE NAM BUT 
TONIGHT THE ROLES HAVE REVERSED AS THE NAM HAS MORE MOISTURE THEN 
THE GFS. THUS OVERALL CONFIDENCE IN EITHER MODEL IS POOR AT BEST 
WITH REGARDS TO HOW MUCH MOISTURE THERE WILL BE.  WILL KEEP A CHC OF 
SNOW IN THE MTNS THRU MON MORNING AS THERE STILL WILL BE SOME QG 
ASCENT THRU ABOUT 18Z.  OVER NERN CO THE LOW LEVEL FLOW IS FCST TO 
BECOME MORE SSE ON MON AS SFC HIGH SLIDES EAST OVER THE CENTRAL 
PLAINS SO THERE IS NO UPSLOPE FLOW IN PLACE.  MEANWHILE BOTH THE NAM 
AND GFS KEEP BEST MOISTURE ABOVE 700 MB SO WILL KEEP POPS ON THE LOW 
SIDE.  LATEST SOUNDINGS SHOW WET BULB ZEROS DROP TO AROUND 5500 FEET 
BY 12Z SO COULD SEE SOME LIGHT SNOW OR A MIX IF ANY SHOWERS DO 
DVLP.  HIGHS ON MON WILL BE AROUND 10 DEGREES COOLER THAN SUN BASED 
ON LATEST 850-700 MB TEMPS OVER THE PLAINS.

FOR TUE AND WED SW FLOW ALOFT WILL BE OVER THE AREA AS A LEE TROUGH 
SETS UP OVER NERN CO.  THIS SHOULD LEAD TO A DRY PERIOD WITH 
POSSIBLY SOME HIGH LEVEL CLOUDS BY WED AS SOME MOISTURE GETS 
ADVECTED IN FM THE SW.  850-700 MB TEMPS ARE FCST TO RISE FROM 5 TO 
6 DEGREES C ON TUE AND ANOTHER COUPLE OF DEGREES ON WED.  THIS 
SHOULD ALLOW FOR HIGHS TO RISE ABOVE ABOVE SEASONAL NORMAL BOTH DAYS 
OVER NERN CO.  

BY THU OR FRI ANOTHER UPPER LEVEL TROUGH MAY AFFECT 
THE AREA.  ONCE AGAIN THE GFS AND ECMWF HAVE VARYING SOLUTIONS WITH 
TIMING OF THIS FEATURE HOWEVER IT APPEARS THE MAIN IMPACT FROM THIS 
FEATURE MAY NOT OCCUR UNTIL FM THU NIGHT INTO FRI.  FOR NOW WILL 
KEEP A CHC OF POPS IN THE MTNS WITH LOW POPS OVER THE PLAINS.  A 
CDFNT WILL LIKELY AFFECT NERN CO EITHER THU AFTN OR THU NIGHT. THUS 
HIGHS ON THU WILL DEPEND ON HOW FAST FNT MOVES INTO AREA.  IF FNT 
HOLDS OFF UNTIL THU NIGHT THEN HIGHS ON THU MAY ONCE AGAIN BE IN THE 
60S AS DOWNSLOPE SWLY LOW LEVEL FLOW WILL BE IN PLACE.  ON FRI TEMPS 
WILL BE QUITE A BIT COOLER WITH READINGS POSSIBLY DROPPING BACK INTO 
THE 40S ACROSS NERN CO.

&&

.AVIATION...HIGH END VFR CONDITIONS EXPECTED TO CONTINUE THROUGH 
THIS AFTERNOON.  AFTER 01Z WE MAY SEE CIGS DROP TO BKN-OVC060-080 
ALONG WITH SOME AREAS OF LIGHT PRECIP.  DURING THE AFTERNOON WILL 
ALSO SEE WINDS SWITCH TO A NORTHERLY DIRECTION DUE TO PASSAGE OF A 
WEAK COLD FRONT.  PRECIP MAY BE A MIX OF RAIN AND SNOW...BUT NO 
ACCUMULATIONS ARE EXPECTED.

&&

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

$$

KDRBY/RPK