Red Flag Warning 1, NWS Denver/Boulder, CO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
350 AM MST SAT MAR 1 2008

.SHORT TERM...EARLY SPRING-LIKE CONDITIONS WILL PREVAIL TODAY WITH
TEMPERATURES APPROACHING RECORD LEVELS ACROSS THE PLAINS. RECORD
HIGH AT DENVER TODAY 73...WONT BE TOO FAR OFF. HIGH PRESSURE RIDGE
ALOFT AND LEESIDE TROFING PRODUCING GUSTY S-SWLY WINDS ALONG THE
FOOTHILLS AND OVER THE PALMER DIVIDE SHOULD SEND MIDDAY RELATIVE
HUMIDITIES DOWN INTO THE 10 TO 15 PCT RANGE IN THESE AREAS. FARTHER
OUT ACROSS THE PLAINS WHERE LIGHTER S-SELY WINDS WILL PREVAIL
DEWPOINTS AND RHS NOT EXPECTED TO BE AS LOW. BECAUSE OF THE
UNSEASONABLY WARM TEMPS WITH AMPLE SUNSHINE...VERY LOW RHS AND GUSTY
S-SWLY WINDS OF AT LEAST 25 MPH...WILL BE ISSUING A RED FLAG WARNING
FOR ZONES 39-41 AND 46-47 WITH THIS MORNING/S GRIDDED FCST. THIS
WARNING WILL RUN FM 16Z THIS MORNING TO 01Z THIS EVENING. LITTLE OR
NO PRECIP IN RECENT DAYS ANOTHER REASON FOR THE ABOVE MENTIONED
WARNING. EVEN THOUGH THE FOOTHILLS WILL NOT BE UNDER THIS WARNING
BECAUSE OF WETTER FUEL CONDITIONS...SHOULD STILL SEE QUITE A BIT OF
WIND AND VERY LOW RHS TODAY. COULD SEE SWLY CHINOOK WINDS GUSTING
45-55MPH AT TIMES...ESPLY IN FOOTHILL AREAS SOUTH OF INTERSTATE
70.

BY TONIGHT...ATTENTION SHIFTS TO THE STRONG COLD FRONT AND DEEP
UPPER TROUGH NOW DROPPING OUT OF THE PACIFIC NORTHWEST. NAM AND GFS
DIFFER QUITE A BIT IN THE AMOUNT OF MOISTURE WITH THIS SYSTEM. NAM
PAINTS A DRY PICTURE FOR AREAS EAST OF THE MTNS...WHILE THE GFS A
MUCH WETTER ONE. FEEL IT NECESSARY TO GO WITH A BLEND OF THE TWO
MODELS SINCE BOTH HAVE THEIR GOOD AND BAD POINTS. WIND FIELDS ON
BOTH MODELS SHOW THE COLD FRONT SWEEPING OVER THE NRN MTNS LATE THIS
EVENING AND SWRD ACROSS THE NERN PLAINS AFTER MIDNIGHT WITH FRONTAL
PASSAGE AT DENVER AROUND 09Z. NOT EXPECTING TO SEE MUCH IF ANY
PRECIPITATION WITH THE FRONT ITSELF DUE TO A VERY DRY BNDRY LAYER...
BUT AS THE TROUGH DRAWS NEAR SO DOES A STG UPR LEVEL JET WHICH WILL
PROVIDE ADDED LIFT NECESSARY TO GENERATE SOME BANDED PRECIPITATION
(RAIN AND/OR SNOW) TOWARDS MORNING LIGHT. ACCUMULATING SNOWFALL IN
THE HIGH COUNTRY NOT EXPECTED UNTIL AFTER MIDNIGHT WHEN 700-500 MB
LAYER WINDS SHIFT FM SWLY TO A MORE FAVORABLE WLY DIRECTION AFTER
FROPA. LOCAL OROGRAPHIC SNOW MODEL USING INPUTS FROM THE GFS
GENERATED 1-4 INCH SNOW AMTS BY 12Z/SUNDAY IN MTN AREAS ALONG AND
WEST OF THE CONTINENTAL DIVIDE. INCREASING WIND SPDS LATE TONIGHT
SHOULD ALSO PRODUCE AREAS OF BLOWING SNOW OVER HIGHER ELEVATIONS.

.LONG TERM...LATEST NAM AND GFS ARE ABOUT AS OUT OF PHASE AS THEY
CAN GET FOR SUN.  ALTHOUGH BOTH SHOW AND UPPER LEVEL TROUGH MOVING
ACROSS THE AREA WITH DECENT MID LEVEL QG ASCENT THE NAM SHOWS NWLY
DOWNSLOPE FLOW FROM THE FOOTHILLS INTO THE PLAINS WHILE THE GFS HAS
MORE OF NNE LOW LEVEL COMPONENT.  ALL DURING THE WINTER THE NAM HAS
CONSISTENTLY HAD A DOWNSLOPE BIAS WHILE THE GFS HAS HAD MORE OF AN
UPSLOPE BIAS.  THUS WILL TREND MORE IN LINE WITH THE GFS AND GO WITH
HIGHER POPS ALONG THE FRONT RANGE INTO THE PLAINS ESPECIALLY ACROSS
THE SRN FOOTHILLS AND PALMER DIVIDE AREAS.  THICKNESS VALUES SUGGEST
PCPN WILL FALL MOSTLY AS SNOW ACROSS NERN CO.  SNOW ACCUMULATIONS OF
AN INCH OR TWO MAY OCCUR OVER THE PLAINS WITH HIGHER AMOUNTS
POSSIBLE OVER THE SRN FOOTHILLS AND PALMER DIVIDE.  TEMPS WILL BE
CONSIDERABLY COLDER ON SUN AS 850-700 MB TEMPS DROP AROUND 15
DEGREES C.  IN THE MTNS AND HIGHER VALLEYS WILL SEE SOME SNOW ON SUN
AS WELL BUT AMOUNTS SHOULD STAY BLO ADVISORY CRITERIA.

BY SUN NIGHT AS THE UPPER LEVEL TROUGH MOVES SE OF THE AREA PCPN
SHOULD GRADUALLY END DURING THE EARLY EVENING HOURS.  ON MON DRY NLY
FLOW ALOFT WILL BE OVER THE AREA.  850-700 MB TEMPS WILL MODERATE
SOME ON MON WITH HIGH TEMPS GENERALLY IN THE 40S OVER THE PLAINS.
FOR TUE NWLY FLOW ALOFT WILL INCREASE IN ADVANCE OF ANOTHER SYSTEM
WHICH WILL AFFECT THE AREA BY WED.  BEFORE THIS SYSTEM ARRIVES
DOWNSLOPE LOW LEVEL FLOW WILL OCCUR OVER LOWER ELEVATIONS WHICH
SHOULD ALLOW FOR HIGHS TO RISE INTO THE 50S ACROSS NERN CO.  WITH
INCREASING FLOW ALOFT WINDS WILL INCREASE IN THE MTNS AND FOOTHILLS.

FOR TUE NIGHT INTO WED ANOTHER UPPER LEVEL TROUGH IS FCST TO MOVE
ACROSS THE AREA.  A CDFNT WILL MOVE INTO NERN CO TUE NIGHT WITH THE
LATEST GFS SHOWING UPSLOPE DEVELOPING ON WED.  THUS THIS MAY LEAD TO
ANOTHER CHC OF SNOW OVER LOWER ELEVATIONS ALONG WITH COLDER TEMPS.
IN THE MTNS WILL SEE A CHC OF SNOW AS WELL AS THE UPPER LEVEL TROUGH
MOVES ACROSS.  BY THU THE UPPER LEVEL TROUGH WILL MOVE SE OF THE
AREA WITH NWLY FLOW ALOFT.  SOME SHALLOW MOISTURE MAY LINGER IN THE
MTNS SO WILL KEEP IN A SLIGHT CHC OF SNOW.  OVER NERN CO IT SHOULD
BE DRY WITH HIGHS WARMING FROM 5 TO 10 DEGREES.

.AVIATION...VFR CIGS AND VSBYS WILL PREVAIL THROUGH MIDNIGHT
TONIGHT. AFTER MIDNIGHT PASSAGE OF A STRONG COLD FRONT WILL USHER IN
LOWER CIGS AND A CHANCE OR RAIN OR SNOW. IN THE DENVER AREA...MAY
SEE LCL MVFR CIGS FORMING AFTER 09Z.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...RED FLAG WARNING FOR THE SOUTHERN
FRONT RANGE URBAN CORRIDOR...PALMER DIVIDE...EASTERN ELBERT AND
LINCOLN COUNTIES FROM 16Z/SAT TO 01Z/SUN...ZONES 39-41 AND 46-47.

&&

BAKER/RPK

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DENVER CO
1107 AM MST FRI FEB 29 2008

COZ030>051-011300-
JACKSON COUNTY BELOW 9000 FEET-WEST JACKSON AND WEST GRAND
COUNTIES ABOVE 9000 FEET-GRAND AND SUMMIT COUNTIES BELOW 9000
FEET-SOUTH AND EAST JACKSON/LARIMER/NORTH AND NORTHEAST GRAND/
NORTHWEST BOULDER COUNTIES ABOVE 9000 FEET-SOUTH AND SOUTHEAST
GRAND/WEST CENTRAL AND SOUTHWEST BOULDER/GILPIN/CLEAR CREEK/
SUMMIT/NORTH AND WEST PARK COUNTIES ABOVE 9000 FEET-LARIMER AND
BOULDER COUNTIES BETWEEN 6000 AND 9000 FEET-JEFFERSON AND WEST
DOUGLAS COUNTIES ABOVE 6000 FEET/GILPIN/CLEAR CREEK/NORTHEAST PARK
COUNTIES BELOW 9000 FEET-CENTRAL AND SOUTHEAST PARK COUNTY-LARIMER
COUNTY BELOW 6000 FEET/NORTHWEST WELD COUNTY-BOULDER AND JEFFERSON
COUNTIES BELOW 6000 FEET/WEST BROOMFIELD COUNTY-NORTH DOUGLAS
COUNTY BELOW 6000 FEET/DENVER/WEST ADAMS AND ARAPAHOE COUNTIES/
EAST BROOMFIELD COUNTY-ELBERT/CENTRAL AND EAST DOUGLAS COUNTIES
ABOVE 6000 FEET-NORTHEAST WELD COUNTY-CENTRAL AND SOUTH WELD
COUNTY-MORGAN COUNTY-CENTRAL AND EAST ADAMS AND ARAPAHOE COUNTIES-
NORTH AND NORTHEAST ELBERT COUNTY BELOW 6000 FEET/NORTH LINCOLN
COUNTY-SOUTHEAST ELBERT COUNTY BELOW 6000 FEET/SOUTH LINCOLN
COUNTY-LOGAN COUNTY-WASHINGTON COUNTY-SEDGWICK COUNTY-PHILLIPS
COUNTY-
1107 AM MST FRI FEB 29 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL
COLORADO.

.DAY ONE...TODAY AND TONIGHT

AN UPPER LEVEL RIDGE OVER COLORADO TODAY WILL PRODUCE DRY AND MILD
WEATHER ACROSS NORTH CENTRAL AND NORTHEAST COLORADO TODAY. WINDS
WILL INCREASE LATER TONIGHT OVER THE MOUNTAINS AND NEAR THE
FOOTHILLS. WIND GUSTS TO 45 MPH WILL BE POSSIBLE.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

GUSTY CHINOOK WINDS WILL CONTINUE FOR MUCH OF SATURDAY IN AND NEAR
THE FRONT RANGE FOOTHILLS. WIND GUSTS TO AROUND 40 MPH IN THE
FOOTHILLS AND NEAR 30 MPH ALONG THE BASE OF THE FOOTHILLS CAN BE
EXPECTED. THE DRY AND WARM WEATHER ON SATURDAY WILL BE REPLACED BY
MUCH COLDER AND MOIST CONDITIONS FOLLOWING THE PASSAGE OF A STRONG
PACIFIC COLD FRONT LATE SATURDAY NIGHT. SNOWFALL WILL BE LIKELY IN
THE MOUNTAINS LATE SATURDAY NIGHT THROUGH SUNDAY WITH SEVERAL INCHES
OF SNOW ACCUMULATION POSSIBLE. THERE WILL ALSO BE A CHANCE OF RAIN
OR SNOW AT LOWER ELEVATIONS DURING THE SAME PERIOD. AT THIS TIME
LITTLE OR NO SNOW ACCUMULATION IS ANTICIPATED ON THE PLAINS OF
NORTHEAST COLORADO.

A SECOND PACIFIC STORM SYSTEM MAY PRODUCE ANOTHER ROUND OF SNOW AND
COLD TEMPERATURES LATE TUESDAY INTO WEDNESDAY OF NEXT WEEK.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT.

DANKERS/DL