000
FXUS65 KBOU 192156
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
256 PM MST WED NOV 19 2008
.SHORT TERM...A DECENT BOUNDARY IS MOVE SOUTHEASTWARD ACROSS THE
PLAINS RIGHT NOW. NORTHEASTERLY FLOW BEHIND IT IS GUSTY TO AROUND
20 KNOTS RIGHT NOW. THE STRATUS IS QUITE AWAYS AWAY YET IN
NORTHEASTERN WYOMING AND NORTH CENTRAL NEBRASKA. DEW POINTS IN
THOSE AREAS AREA ARE IN THE 25 TO 30 F RANGE. TEMPERATURES BEHIND
THE FRONT ARE DROPPING 3-4 F PER HOUR. I FIGURE SUNSET WILL HELP
QUITE A BIT AND LOW CLOUDS WILL GET INTO OUR PLAINS BY MID
EVENING. MODELS HAVE CHANGED LITTLE. THERE IS STILL WEAK UPWARD
MOTION PROGGED IN THE SYNOPTIC SCALE TONIGHT AND THURSDAY. THERE
IS STILL A FLATTENING RIDGE ALOFT WITH INCREASING
WEST-NORTHWESTERLY JET LEVEL FLOW. THE BOUNDARY LAYER FLOW IS
PRETTY UNIFORM EASTERLY TONIGHT AND THURSDAY AT LEAST UP INTO THE
FOOTHILLS. FOR MOISTURE...700 MBS AND BELOW LOOK SATURATED FROM 06Z
TONIGHT THROUGH 00Z THURSDAY AFTERNOON. THE GFS IS A BIT DEEPER
THAN THE NAM WITH THE MOISTURE. BOTH SHOW LITTLE MOISTURE ABOVE
THAT. FORECAST SOUNDING CONTINUE TO POINT TO A DRIZZLE EVENT...
FREEZING DRIZZLE MUCH OF THE TIME. WILL CHANGE LITTLE WITH THE
POPS. FOR TEMPERATURES...THURSDAY`S HIGHS ARE 9-12 C COLDER THAN
THIS AFTERNOON`S.
.LONG TERM...SOME QUESTION ABOUT HOW QUICKLY THE LOW CLOUDINESS WILL
ADVECT OUT OF THE AREA. SOUTHERLY WINDS WILL INCREASE THURSDAY NIGHT
AND FLOW AT THE TOP OF THE CLOUD DECK WILL BEGIN TO GET A WESTERLY
COMPONENT. THIS SHOULD PUT A HOLE IN THE CLOUDS ON THE NORTH SIDE OF
THE PALMER DIVIDE. HOWEVER...THIS IS A GOOD PATTERN FOR A DENVER
CYCLONE WHICH WILL LIKELY TEND TO HOLD THE LOW CLOUDS IN AGAINST THE
FOOTHILLS FROM DENVER NORTHWARD. EVENTUALLY THIS AREA SHOULD ERODE
AS THE TOP OF THE DECK BLOWS AWAY DURING THE MORNING...OR AT LATEST
BE PUSHED OUT AS DRIER AIR MOVES IN FROM THE NORTH BEHIND ANOTHER
WEAK COLD FRONT LATER IN THE DAY. I DID KEEP SOME DRIZZLE THROUGH
THURSDAY NIGHT AND HANG ON TO MORE CLOUD COVER ON FRIDAY.
TEMPERATURES WILL STILL WARM NICELY IN THE AFTERNOON. MODELS
CONTINUE TO SHOW THE FRIDAY SYSTEM ALOFT PASSING MAINLY NORTH OF
COLORADO...WITH THE FURTHER SOUTH NAM SKIRTING THE NORTHERN BORDER
WITH CLOUDS AND POSSIBLY MOUNTAIN SHOWERS. OVERALL THOUGH IT LOOKS
PRETTY DRY ONCE THE LOW LEVELS ON THE PLAINS FLUSH OUT.
THERE IS BETTER CONSISTENCY SINCE LAST NIGHTS MODELS ON A SHORTWAVE
PASSING NORTH OF US ON SUNDAY...THEN RIDGING AGAIN AS A TROUGH
DEVELOPS OVER THE EAST. AGAIN THE AIR MASS LOOKS TO BE PRETTY
DRY...THOUGH THE ECMWF DOES HAVE THE SYSTEM FAR ENOUGH SOUTH TO
THREATEN SOME CLOUDS AND MOUNTAIN SHOWERS. NO BIG HEAT WAVE BUT DRY
WITH ABOVE NORMAL TEMPERATURES MONDAY AND TUESDAY...NORMAL HIGHS ARE
NOW AROUND 50. UPSTREAM TROUGH DEVELOPING ALONG THE COAST MAY SPREAD
MOISTURE AND POSSIBLY COLDER AIR LATE IN THE WEEK...WEDNESDAY AT
EARLIEST BUT PROBABLY LATER. MAYBE SOME LIGHT SNOW FOR THE MOUNTAINS
BY THANKSGIVING BUT NOT LOOKING LIKE ANYTHING SIGNIFICANT BEFORE
NEXT WEEKEND.
&&
.AVIATION...A COLD FRONT IS PUSHING THROUGH THE AREA AT THIS TIME.
BY 05Z THIS EVENING...CEILINGS SHOULD BE IFR AT THE THREE AIRPORTS.
VISIBILITIES DUE TO FREEZING DRIZZLE AND FOG SHOULD BE IFR BY ABOUT
09Z THURSDAY MORNING. IFR CONDITIONS SHOULD CONTINUE AT LEAST
THROUGH 21Z THURSDAY AFTERNOON.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...NONE.
$$
RJK/GIMMESTAD
