National Weather Service Forecast Discussion

000
FXUS65 KBOU 290841
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
240 AM MDT FRI AUG 29 2008

.SHORT TERM...HIGH PRESSURE AT LOWER LEVELS IS SHIFTING
EASTWARD...WITH THE RESULTING SOUTHERLY FLOW BRINGING A LITTLE
WARMING AND INCREASING MOISTURE AT LOW LEVELS OVER THE SOUTHERN AND
EASTERN PARTS OF OUR FORECAST AREA. MEANWHILE...MUCH DRIER AIR LIES
OVER THE NORTHERN BORDER AREAS. THE LOW LEVEL WARMING/MOISTENING
WILL CREATE MARGINAL CONDITIONS FOR CONVECTION TODAY...AND SOME
PLACES SHOULD GET WARM ENOUGH TO INITIATE THUNDERSTORMS. THIS WILL
BE MOST LIKELY IN THE ELEVATED TERRAIN AROUND SOUTH PARK WHICH
SHOULD HAVE THE BEST COMBINATION OF HEAT AND MOISTURE. FLOW IS LIGHT
BUT CELL GROWTH SHOULD BE TOWARD THE SOUTHEAST INTO LOW LEVEL FLOW...
SO STORMS SHOULD DEVELOP IN THAT DIRECTION. HIGHEST POPS ALREADY
PLAYED SOUTH AND SOUTHWEST OF DENVER...AND I WILL REMOVE POPS ALONG
THE NORTHERN BORDER AREAS. FORECAST HIGH TEMPERATURES LOOK A LITTLE
AMBITIOUS BUT WITH THE SOUTHERLY FLOW I WILL STICK WITH THEM...NEARER
THE COOLER NAM MOS GUIDANCE. LITTLE CHANGE THIS EVENING...WILL KEEP
LOW POPS GOING IN THE EVENING AS THE SOUTHEAST LOW LEVEL WINDS
CONTINUE...THEN CLEARING OVERNIGHT...POSSIBLY SOME STRATUS LATE NEAR
THE EASTERN BORDER.

.LONG TERM...MODELS HAVE WESTERLY FLOW ALOFT FOR THE FORECAST AREA
SATURDAY AND SATURDAY EVENING.  SOUTHWESTERLY FLOW ALOFT IS PROGGED
OVERNIGHT SATURDAY INTO SUNDAY.  IT BECOMES MORE SOUTH-SOUTHWESTERLY
ALOFT BY SUNDAY EVENING INTO MONDAY WITH A DECENT UPPER
TROUGH/CLOSED LOW GETTING INTO THE GREAT BASIN.  THE QG VERTICAL
VELOCITY FIELDS HAVE WEAK UPWARD MOTION PROGGED OVER THE FORECAST
AREA FROM SATURDAY WELL INTO MONDAY.  THE BOUNDARY LAYER FLOW IS
PROGGED TO BE SOUTHERLY THROUGH MOST OF THE PERIODS.  FOR MOISTURE
...IT IS FAIR BOTH DAYS OF THE WEEKEND.  THERE IS SOME IN THE LOWER
LEVELS OVER THE PLAINS SATURDAY MORNING.  PRECIPITABLE WATER VALUES
ARE IN THE 0.60 TO 0.90 INCH RANGE SATURDAY INTO SUNDAY EVENING.
THE BOUNDARY LAYER DEW POINTS ARE IN THE MID 40S TO UPPER 50S F
THROUGH MOST OF THE PERIODS.  THERE IS A THETA-E AXIS OVER FAR
EASTERN COLORADO FOR LATE DAY SATURDAY.  BY SUNDAY...A WEAKER
THETA-E AXIS IS OVER MOST OF THE FORECAST AREA.  THERE IS SOME CAPE
OVER THE FOOTHILLS AND PLAINS FOR LATE DAY SATURDAY.  ON SUNDAY
...THERE IS SOME CAPE OVER THE WESTERN THIRD OF THE FORECAST AREA
AREA...WITH MINIMAL AMOUNTS OVER THE PLAINS.  THE LAPSE RATE FIELDS
SHOW A PRETTY SUBSTANTIAL CAP IN THE MID LEVELS FOR MUCH OF THE
FORECAST AREA BOTH DAYS.  FOR LATE DAY SUNDAY...IT IS ESPECIALLY
STRONG OVER THE EASTERN PLAINS.  THE QPF FIELDS HAVE SMALL
MEASURABLE AMOUNTS OF RAINFALL OVER THE SOUTHWESTERN FORECAST AREA
FOR LATE DAY SATURDAY.  ON SUNDAY...THERE IS A TAD OVER THE WESTERN
HALF OF THE FORECAST AREA.  FOR POPS...WILL GO WITH MAINLY 10%S FOR
THE MOUNTAINS AND ADJACENT PLAINS ON SATURDAY.  WILL LOWER CURRENT
POP GRIDS ON SUNDAY TO 10-20%S...WITH POOR MOISTURE AND CAPPING IN
MIND.  FOR TEMPERATURES...SATURDAY`S HIGHS ARE 2-3 C WARMER THAN
FRIDAY`S.  SUNDAY`S ARE 1-2 C COOLER THAN SATURDAY`S.  FOR THE LATER
DAYS...MONDAY THROUGH THURSDAY...MODELS ARE SHOWING A DECENT CLOSED
LOW OVER THE GREAT BASIN ON MONDAY...WITH SOUTHERLY FLOW ALOFT FOR
THE FORECAST AREA.  THEY SHOWING THE FEATURE LIFTING OUT TO THE
NORTHEAST ON TUESDAY INTO WEDNESDAY WITH THE UPPER TROUGH WEAKENING
AS IT`S AXIS MOVES ACROSS COLORADO AROUND WEDNESDAY.  THESE LATEST
MODELS RUNS LOOK A BIT DIFFERENT FROM WHAT I SAW LAST NIGHT.  WILL
LEAVE THINGS ALONE FOR THE MOST PART.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED THROUGH TONIGHT. ISOLATED
HIGH BASED THUNDERSTORMS ARE EXPECTED DURING THE LATE AFTERNOON AND
EVENING...MAINLY SOUTHWEST AND SOUTH OF DENVER.

&&

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

$$
GIMMESTAD/RJK

NWS BOU Office Area Forecast Discussion