National Weather Service Forecast Discussion

000
FXUS65 KBOU 192136
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
330 PM MDT FRI MAR 19 2010

.SHORT TERM...INTERESTING STORM CONTINUES IN SOME AREAS AND IS
WINDING DOWN IN MANY OTHERS.  GOT OFF TO A SLOWER START AS THE BAND
IN THE EARLY MORNING HOURS ASSOCIATED WITH THE UPPER LEVEL JET
ACTUALLY PRODUCED SOME RAIN AND EVEN RARE FREEZING RAIN FOR AWHILE
BEFORE FINALLY GOING TO SNOW BUT BY THEN HAD PASSED MORE TO OUR
SOUTH.  TODAY WE HAVE BEEN TRANSISITIONING TO A MORE FRONT RANGE
FOCUSED STORM WITH DEEPENING UPSLOPE AS THE MAIN UPPER LEVEL LOW IS
STILL OVER WESTERN COLORADO DROPPING TO THE SOUTHEAST.  INTERESTING
ON THE RADAR AS WE HAVE BEEN GETTING CONVECTIVE LIKE AREAS OF SNOW
FORMING EVEN NORTH OF CHEYENNE AND MOVING TO THE SW AND THEN INTO
THE FRONT RANGE.  THESE HAVE PRODUCED AND CONTINUE TO PRODUCE SOME
VERY IMPRESSIVE SNOWFALL RATES OFTEN WELL IN EXCESS OF 2 INCHES PER
HOUR AND BY THE TIME IT IS OVER FAVORABLE FOOTHILL AREAS WILL BE
OVER 20 INCHES.  THERE ARE STILL SOME REALLY STRONG ECHOES OVER 30
DBZ THAT ARE NOW HEADING INTO THE DENVER AREA AND WILL REALLY HIT
JEFFERSON AND DOUGLAS COUNTIES INTO THE EVENING.  SO WILL CONTINUE
THE WINTER STORM WARNING AND WE HAVE WORDED THINGS TO INDICATE WHERE
THE HEAVIER SNOWS WILL BE.  MANY OF THE ROADS IN THE DENVER AREA
HAVE BEEN JUST WET BUT WITH HEAVY SNOW RATES IN THESE BANDS AND
DECREASING SUN ANGLE COULD GET SLIPPERY LATER THIS AFTERNOON INTO
THE EVENING.

IN THE MOUNTAINS AMOUNTS HAVE BEEN MUCH LESS WITH THE UNFAVORABLE
ORGRAPHIC FLOW WEST OF THE DIVIDE AND THE WARNING WILL EXPIRE THERE
AT 00Z.  ON THE PLAINS WILL LET THAT ONE STAY UNTIL EXPIRATION AT
00Z MORE NE PLAINS AND 06Z SOUTHERN PORTIONS.  NOT A LOT OF
ADDITIONAL SNOWFALL BUT WINDS ARE GUSTY NOW AND GETTING A LITTLE
COLDER SO ANY ADDITIONAL SNOW COULD CREATE SOME SLIPPERY ROADS...SO
NO SENSE CANCELLING IT EARLY AT THIS POINT.  OTHERWISE THINGS
IMPROVE RAPIDLY BY SATURDAY.  SOME EARLY MORNING FOG ON THE EASTERN
PLAINS DEPENDING ON THE AMOUNT OF CLEARING.  IF ENOUGH CLEARING THEN
SOME PRETTY COLD TEMPS WILL OCCUR WITH THE NEW SNOW COVER.

.LONG TERM...UPPER LEVEL RIDGE AXIS WILL BE BUILDING ACROSS THE
NORTHERN AND CENTRAL ROCKIES SATURDAY NIGHT THROUGH SUNDAY.  THIS
WILL BRING DRY CONDITIONS AND WARMING TEMPS.  WARMUP WILL BE DELAYED
A BIT DUE TO SNOW COVER...BUT BY SUNDAY AFTERNOON MOST LOCATIONS
SHOULD STILL BE ABLE TO REACH 50F OR SLIGHTLY BETTER.

ON MONDAY...DOWNSLOPE FLOW WILL INCREASE WITH CONSIDERABLE WARMING
ALOFT.  THIS WILL HELP READINGS WARM TO AT LEAST THE LOWER 60S
ACROSS THE PLAINS UNDER MOSTLY SUNNY SKIES.

BY TUESDAY...THE NEXT TROUGH WILL APPROACH THE AREA...AND EACH
SUCCESSIVE RUN OF THE ECWMF AND GFS ENSEMBLES ARE POINTING TOWARD A
POTENTIAL FOR ANOTHER HEALTHY PRECIPITATION EVENT LATE TUESDAY INTO
WEDNESDAY. MOST OF THIS PRECIPITATION SHOULD END UP IN THE FORM OF
SNOW AS EVERYTHING POINTS TO ENOUGH COLD AIR COMING IN BEHIND THE
NEXT FRONT.  HAVE INCREASED POPS A BIT MORE AND LOWERED TEMPS A FEW
MORE DEGREES TUESDAY NIGHT AND WEDNESDAY AS A RESULT.  WE DO HAVE TO
WATCH HOW FAR SOUTH THIS TROUGH DIGS...BUT THERE IS POTENTIAL FOR
ANOTHER ACCUMULATING SNOWFALL ACROSS THE FORECAST AREA TUESDAY NIGHT
THROUGH WEDNESDAY.

THEN BACK TO DRY AND WARMER CONDITIONS IN TYPICAL SPRING FASHION FOR
THE END OF NEXT WEEK.

.AVIATION...AREAS OF HEAVIER SNOW THAT HAVE BEEN FORMING UP IN WELD
COUNTY CONTINUE TO MOVE TO THE SW AND WILL BRING SOME PERIODS OF
HEAVIER SNOWS UNTIL ABOUT 00Z WITH APA MAINLY IN THE PATH OF SOME OF
THESE BJC AND DIA MORE ON THE EDGE.  OTHERWISE IMPROVING CONDITIONS
AFTER 00Z AND SHOULD BE DONE BY 06Z.  AREAS OF FOG POSSIBLE AT DIA
AFTER 09Z WITH SOME CLEARING SKIES LATE.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...WINTER STORM WARNING
   UNTIL MIDNIGHT TONIGHT FOR THE FRONT RANGE MOUNTAINS...
   FOOTHILLS...AND ADJACENT PLAINS INCLUDING MOST OF THE FRONT
   RANGE URBAN CORRIDOR AND PALMER DIVIDE...ZONES 33>36..39>41.
...WINTER WEATHER ADVISORY FOR THE NORTHEASTERN PLAINS OF COLORADO
   UNTIL 6 PM MDT TONIGHT...ZONES 42>44..AND 48>51.
...WINTER WEATHER ADVISORY FOR EAST CENTRAL COLORADO...SOUTH
   PARK...AND THE PARK/GORE RANGES UNTIL MIDNIGHT MDT TONIGHT...
   ZONES 45..46..31..AND 37.

$$

SZOKE/BARJENBRUCH

NWS BOU Office Area Forecast Discussion