000
FXUS65 KBOU 251002
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
300 AM MST WED NOV 25 2009

.SHORT TERM...WATER VAPOR IMAGERY SHOWING A RAPIDLY MOVING 
DISTURBANCE DIGGING INTO THE CENTRAL PLAINS STATES THIS AM. THIS 
DISTURBANCE AND ASSOCIATED WEAK FRONT WILL BRUSH THE PLAINS OF 
NORTHEAST COLORADO THROUGH THE MORNING HOURS. THE FRONT IS JUST 
MOVING INTO NORTHEAST COLORADO ATTM AND STRATUS RAPIDLY DEVELOPING 
OVER NORTHERN SECTIONS OF THE PLAINS. REGIONAL RADARS SHOWING SOME 
LIGHT ECHOES ACROSS NEBRASKA AND KANSAS SO WILL MAINTAIN THE 
ISOLATED POPS ACROSS THE FAR NORTHEAST ZONES. MOST OF THE UPWARD 
VERTICAL VELOCITIES ARE ACROSS NEBRASKA AND KANSAS SO NOT MUCH 
LITTLE HELP FROM UPSTAIRS WITH THIS SYSTEM. APPEARS ENOUGH OF A 
SURFACE PRESSURE RISE TO RESULT IN FRONTAL PUSH ACROSS MUCH OF THE 
FRONT RANGE AND LOOKS LIKE WE WILL HAVE STRATUS THROUGH THE MID 
MORNING HOURS.  THERE WILL BE RAPID IMPROVEMENT LATER THIS AM AND 
AFTERNOON AS THE SYSTEM MOVES INTO THE UPPER MID WEST BY LATE IN THE 
DAY. CLEARING SKIES EXPECTED ACROSS ALL LOCALES TONIGHT.  

.LONG TERM...A SUNNY AND WARM THANKSGIVING DAY CAN BE EXPECTED WITH 
AN UPPER LEVEL RIDGE SPREADING FROM THE GREAT BASIN INTO THE CENTRAL 
AND SOUTHERN ROCKIES.  LIGHT WESTERLY FLOW ALOFT WILL HELP DOWNSLOPE 
WARMING...SO HIGHS SHOULD BE ABLE TO REACH 60F OR SLIGHTLY BETTER 
ACROSS THE PLAINS.  EVEN WARMER TEMPERATURES CAN THEN BE EXPECTED 
FRIDAY AS THE RIDGE AXIS MOVES ACROSS COLORADO.  700 MB TEMPS WARM 
TO AROUND 6C AND AIRMASS IS VERY DRY PER CROSS SECTIONS SO FULL 
SUNSHINE IS EXPECTED.  AS A RESULT...HAVE WARMED UP HIGHS SEVERAL 
DEGREES FOR FRIDAY.

BY FRIDAY NIGHT...THE NEXT TROUGH WILL BEGIN TO IMPINGE ON COLORADO.
THIS WILL ALLOW A COLD FRONT TO DROP SOUTHWARD ACROSS THE FORECAST 
AREA BY EARLY SATURDAY MORNING...AND USHER IN MUCH COOLER 
TEMPERATURES.  MODELS STILL DIVERGE SIGNIFICANTLY ON THE EVOLUTION 
OF THE UPPER TROUGH AND HOW IT PHASES A STRONG BUNDLE OF ENERGY 
MOVING OFF THE PACIFIC INTO THE LEAD SOUTHWESTERN U.S. TROUGH.  AT 
THIS TIME...MAIN THRUST OF ENERGY SEEN IN THE Q-G VERTICAL MOTION 
FIELDS DROPS NEARLY STRAIGHT SOUTH ACROSS THE DESERT.  THIS WOULD 
NOT BRING MUCH PRECIP TO OUR FORECAST AREA...BUT WITH THE COLD 
ADVECTION AND FRONTAL PASSAGE CANT RULE OUT SOME LIGHT SNOW...
ESPECIALLY IN THE MOUNTAINS.  

AFTER A BRIEF WARMUP MONDAY AND TUESDAY...THE NEXT TROUGH IS STILL 
SHAPING UP TO BRING ANOTHER SHOT OF COLDER AIR TO THE FORECAST AREA 
BY THE MIDDLE OF NEXT WEEK.

&&

.AVIATION...WEAK SURFACE COLD FRONT TO PUSH SOUTHWARD THROUGH LOCAL 
AIRPORTS BETWEEN 11-13Z AS WINDS SHIFT N-NE BUT GENERALLY UNDER 
15KT. STRATUS WILL DEVELOP QUICKLY THIS AM AND LOOKS LIKE CEILINGS 
COULD DROP BETWEEN 4000-5000 FT AGL AND RESULT IN SOME ILS 
APPROACHES THROUGH 15Z OR SO. CLEARING SKIES LATER THIS AM AND 
AFTERNOON. TYPICAL DRAINAGE WINDS EXPECTED FOR TONIGHT. 

&&

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

$$

SWE/DBB