FXUS65 KBOU 061021
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
415 AM MDT MON OCT 6 2008

.SHORT TERM...CURRENT RADAR SHOWS PRECIPITATION SHIELD BEGINNING TO
SHIFT EASTWARD ACROSS THE PLAINS. THIS TREND WILL CONTINUE THROUGH
THIS MORNING WITH PRECIPITATION ENDING FROM WEST TO EAST ACROSS THE
EASTERN PLAINS AS UPPER LOW LIFTS INTO KANSAS. INCREASINGLY DRY
NORTH TO NORTHWEST FLOW COMBINED WITH SUBSIDENCE BEHIND THE TROUGH
AXIS WILL BRING MOSTLY SUNNY SKIES THEREAFTER. GUSTY WINDS EXPECTED
ON THE PLAINS WITH GUSTS TO 30-35 MPH GIVEN GOOD MIXING AND NORTH
WINDS AROUND 30 KNOTS JUST OFF THE DECK.

FOR TONIGHT...CLEAR SKIES AND A DRY AIRMASS WILL BRING A CHILLY
NIGHT ACROSS THE REGION. WINDS WILL TAKE A FEW HOURS TO DIMINISH
THOUGH WITH DECENT LOW LEVEL GRADIENT TIL MIDNIGHT. THEN STRONG
RADIATIONAL COOLING WILL OCCUR THEREAFTER...WITH LOWS DROPPING INTO
THE 30S. AT THIS TIME...LOOKS LIKE THREAT OF FROST SHOULD BE
CONFINED TO THE FAVORED LOW LYING AREAS. DENVER METRO AREA SHOULD
BE SPARED WITH ENOUGH DRAINAGE WINDS TO KEEP TEMPERATURES UP. WILL
LET DAY SHIFT MAKE THE CALL ON ANY FROST ADVISORIES ACROSS THE
PLAINS.

.LONG TERM...THE BULK OF THE WEEK WILL BE DRY AND WARM AS ZONAL FLOW
DOMINATES THE UPPER AIR PATTERN OVER THE WESTERN U.S. THIS HAS BEEN
WELL ADVERTISED IN THE GRIDS AND FORECASTS FOR THE PAST FEW DAYS.
SOME QUESTIONS REMAIN AS TO HOW RAPID THE WARM-UP WILL BE ON
TUESDAY...SO I TRIMMED A FEW DEGREES OFF OF THE TUESDAY MAXES. NO
OTHER CHANGES TO THE MID PORTION OF THE FORECAST NEEDED ADJUSTING.

THE NEXT ITEM TO BEGIN CONCENTRATING ON IS GOING TO BE WHAT HAPPENS
NEXT WEEKEND. IT APPEARS THAT THE FRIDAY THROUGH SUNDAY PERIOD IS
GOING TO BE UNSETTLED. THE GFS AND ECMWF OPERATIONAL MODELS SHOW
DIFFERING SOLUTIONS WITH A GOOD TROUGH OVER THE INTERMOUNTAIN WEST.
THE ECMWF IS DEEPEST...BUT WITH A FARTHER WEST POSITION. THEN THE
ECMWF EJECTS THE UPPER LOW OVER WYOMING AND THEN IN CANADA. THE GFS
HINTS AT A TROUGH POSITION OVER COLORADO. THE PATTERN EVOLUTION IN
THE LATEST ECMWF LOOKS A LITTLE TOO FAR WEST FOR THE STRENGTH OF THE
LOW. AND ABOUT HALF OF THE GFS ENSEMBLE SOLUTIONS SHOW A
TROUGH/CUTOFF LOW OVER UTAH OR COLORADO. THERE ARE STILL MANY MORE
RUNS TO LOOK AT...SO DID NOT MAKE ANY CHANGES TO THE FORECASTS FOR
NOW. THE IDEA OF COOLER TEMPERATURES ACROSS THE FORECAST AREA IS
GOOD ENOUGH FOR NOW.

&&

.AVIATION...VFR CONDITIONS THROUGH TONIGHT. WINDS WILL TURN MORE
NORTHERLY BY 16-17Z AND INCREASE TO 12-15 KNOTS WITH SOME GUSTS TO
20-25 KNOTS AT DIA...THEN DECREASE BETWEEN 00Z AND 02Z AND GO LIGHT
SOUTHERLY BY 06Z AS TYPICAL DRAINAGE WINDS DEVELOP.

&&

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

$$

BARJENBRUCH/KDRBY






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