High Wind in Colorado, March 31, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
355 AM MDT TUE MAR 31 2009

.SHORT TERM...UPPER LEVEL TROUGH IS EXITING THE REGION RESULTING IN
A NORTHWEST FLOW ALOFT BEHIND IT. NO PRECIPITATION EXPECTED OVER THE
PLAINS TODAY AS THE AIRMASS DRIES. THE NORTHWEST FLOW COMBINED WITH
A MOIST AIRMASS UP TO 550MB WILL SQUEEZE OUT SOME SNOW OVER THE
MOUNTAINS. THE SNOW LOOKS TO BE FOCUSED ON WEST AND NORTHWEST FACING
SLOPES BECAUSE OF THE OROGRAPHIC LIFT. SNOW AMOUNTS WILL BE LIGHT IN
THE MOUNTAINS TODAY WITH ONLY A COUPLE OF INCHES EXPECTED ON FAVORED
SLOPES. TEMPERATURES WILL WARM INTO THE 40S TODAY OVER THE PLAINS.

AN UPPER LEVEL TROUGH WILL DIG SOUTH ACROSS THE GREAT BASIN TONIGHT
AND BE OVER NORTHERN UTAH COME WEDNESDAY MORNING. MOISTURE WILL
DEEPEN OVER THE MOUNTAINS AND LIFT WILL INCREASE WITH THE APPROACH
OF THIS SYSTEM. THIS WILL LEAD TO SNOW BECOMING WIDESPREAD OVER THE
MOUNTAINS THIS EVENING. WILL ISSUE A WINTER WEATHER ADVISORY FOR THE
MOUNTAINS THAT WILL RUN FROM TUESDAY EVENING THROUGH MIDNIGHT
WEDNESDAY NIGHT. SNOWFALL AMOUNTS OF 2 TO 6 INCHES IS EXPECTED BY
WEDNESDAY MORNING. OTHER THAN SOME MID AND UPPER LEVEL CLOUDS...NOT
ENOUGH MOISTURE WILL NOT MAKE OVER THE MOUNTAINS TONIGHT FOR
PRECIPITATION AND WILL KEEP THE PLAINS DRY.

.LONG TERM...WE REMAIN ON WHAT APPEARS WILL BE AN ACTIVE STORM TRACK
THE NEXT WEEK OR SO. GLOBAL MODELS INDICATE A SERIES OF MID/UPPER
TROPOSPHERIC WAVES PROPAGATING ACROSS THE PACIFIC AND EVENTUALLY
OVER THE WRN U.S. APPROXIMATELY EVERY 2-3 DAYS. THE NEXT WAVE IN
THIS SERIES OF RATHER POTENT PERTURBATIONS FORMS ON THE NOSE OF
+160KT JET THAT DIVES OUT OF THE PAC NORTHWEST LATE TODAY. AS AN
UPPER LEVEL RIDGE AMPLIFIES OFF THE WEST COAST THIS JET BECOMES
ORIENTED NORTH-SOUTH WHICH THEN CARVES OUT A SHARP SHORTWAVE TROUGH.
MODELS SHOW HEIGHTS DEEPENING WITH THIS TROUGH AS IT PASSES OVER
COLORADO DURING THE DAY WEDNESDAY. QG VERTICAL VELOCITY FIELDS
INDICATE A BULLS EYE OF MODERATE ASCENT THRU A DEEP LAYER FM THE
FRONT RANGE WEST OF BOULDER TO LIMON AROUND MIDDAY WEDNESDAY...ABOUT
THE SAME TIME A COLD FRONT SLIDES THRU THE AREA FROM WYOMING. NAM
AND GFS INDICATE 1-2 INCH PER HR SNOWFALL RATES IN THE HIGH COUNTRY
THRU THE DAY WITH STEEP LAPSE RATES AND GOOD OROGRAPHICS. COULD SEE
SNOWFALL RATES INCREASE IN THE AFTERNOON AS WINDS SHIFT TO A MORE
FAVORABLE NWLY COMPONENT WITH PASSAGE OF THE TROUGH. HIGH COUNTRY
SNOW TOTALS ON WEDNESDAY IN THE 3-8 INCH RANGE.

ON THE PLAINS...BELIEVE SNOWFALL WILL START SLOWLY WEDNESDAY MORNING
AND INITIALLY UP ALONG THE CHEYENNE RIDGE AND AGAINST THE FRONT
RANGE...BUT BY LATE MORNING WITH DEVELOPMENT OF MODERATE N-NELY
SFC-700MB FLOW AFTER FRONTAL PASSAGE...COULD ONCE AGAIN SEE SEVERAL
HRS OF LIGHT TO MODERATE SNOWFALL WITHIN THE I-25 URBAN CORRIDOR AND
OUT ACROSS THE PALMER DIVIDE. AT THIS TIME DO NOT ANTICIPATE ADVSY
LEVEL SNOW AMOUNTS...BUT COULD STILL SEE 3-6 INCHES ON THE PALMER
DVD...2-4 INCHES IN THE GREAT DENVER METRO AREA AND 1-2 INCH AMTS
OVER NRN PORTIONS OF THE I-25 CORRIDOR AND ADJACENT COUNTIES ON THE
PLAINS. EXPECT TO SEE MOST OF THIS ACCUMULATION IN ABOUT 4-6 HOURS.

SYSTEM QUICKLY MOVES OUT WEDNESDAY NIGHT. THEN ITS ON TO THE NEXT
STORM SYSTEM WHICH MEDIUM RANGE MODELS SHOW DIVING SEWRD OVER THE
GREAT BASIN ON FRIDAY...THEN EAST ACROSS THE FOUR CORNERS REGION AND
THEN ACROSS SOUTHERN COLORADO ON SATURDAY. THIS SYSTEM LOOKS EERILY
SIMILAR TO THE ONE THAT DUMPED OVER A FOOT OF SNOW ON PORTIONS OF
THE DENVER AREA LAST WEEK. WILL HAVE TO WATCH THIS ONE CLOSELY.
BELIEVE IT OR NOT...MODELS INDICATE YET ANOTHER JUICY STORM SYSTEM
FOR NEXT WEEK. WE/LL IGNORE THAT ONE FOR NOW.

&&

.AVIATION...MID AND HIGH CLOUDS WILL STREAM ACROSS THE AREA TODAY
AND TONIGHT. THERE WILL BE A CEILING AT TIMES...RANGING FROM 9000 TO
20000 FEET. LIGHT DRAINAGE WINDS WILL SHIFT TO THE NORTHWEST LATE
THIS MORNING. WIND GUSTS UP TO 20 KNOTS WILL BE POSSIBLE THROUGH
LATE AFTERNOON. LIGHT DRAINAGE WINDS WILL DEVELOP AGAIN THIS EVENING
AND CONTINUE OVERNIGHT.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...WINTER WEATHER ADVISORY NORTHERN
MOUNTAINS TUESDAY 6PM THROUGH MIDNIGHT WEDNESDAY NIGHT...ZONES
31..33 AND 34.

MEIER/BAKER

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE DENVER CO
527 AM MDT TUE MAR 31 2009

COZ030>051-311700-
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-
527 AM MDT TUE MAR 31 2009

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

.DAY ONE...TODAY AND TONIGHT

SCATTERED SNOW SHOWERS WILL LINGER IN THE MOUNTAINS TODAY...MAINLY
ALONG AND WEST OF THE CONTINENTAL DIVIDE. WIND GUSTS TO 50 MPH WILL
CAUSE BLOWING AND DRIFTING SNOW THROUGH THE HIGHER MOUNTAIN PASSES
AND EXPOSED AREAS. SNOW WILL BECOME WIDESPREAD IN THE MOUNTAINS
TONIGHT AS THE NEXT STORM SYSTEM APPROACHES THE STATE.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

SNOWFALL WILL BE LIKELY IN THE HIGH COUNTRY ON WEDNESDAY AS THE
STORM SYSTEM MENTIONED ABOVE PASSES THROUGH COLORADO. EAST OF
THE MOUNTAINS RAIN AND SNOW WEDNESDAY MORNING WILL CHANGE TO SNOW
BY THE AFTERNOON AS TEMPERATURES FALL WITH THE PASSAGE OF A COLD
FRONT. SNOWFALL SHOULD GRADUALLY TAPER OFF DURING THE EVENING AS
THIS STORM SYSTEM EXITS THE REGION. SNOW AMOUNTS WITH THIS
STORM SYSTEM SHOULD RANGE FROM 8 TO 14 INCHES IN THE MOUNTAINS...
TO 2 TO 7 INCHES ON THE HIGH PLAINS BY WEDNESDAY NIGHT. GUSTY WINDS
WILL ALSO PRODUCE AREAS OF BLOWING SNOW ON THE HIGH MOUNTAIN PASSES.
CONDITIONS SHOULD GRADUALLY IMPROVE ON THURSDAY AND FRIDAY ONLY TO
TURN COLDER AGAIN WITH THE POSSIBILITY OF SIGNIFICANT SNOWFALL AND
WIND AREA WIDE ON SATURDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT.

MEIER/BAKER