Severe Thunderstorm Warning 64, NWS Denver/Boulder, CO

000 
WWUS55 KBOU 052344
SVSBOU

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
545 PM MDT TUE JUN 5 2007

COC001-087-121-052355-
/O.CAN.KBOU.SV.W.0064.000000T0000Z-070606T0015Z/
WASHINGTON CO-MORGAN CO-ADAMS CO-
545 PM MDT TUE JUN 5 2007

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN ADAMS...
SOUTHEASTERN MORGAN AND WEST CENTRAL WASHINGTON COUNTIES IS
CANCELLED...

THE THUNDERSTORM THAT PROMPTED THE WARNING HAS WEAKENED AND IS NO
LONGER EXPECTED TO PRODUCE SEVERE WEATHER.

LAT...LON 4003 10393 3980 10394 3980 10348 4010 10347

$$

AREA FORECAST DISCUSSION...CORRECTION TO AVIATION DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
315 PM MDT TUE JUN 5 2007

.SHORT TERM...CONVECTION BEGINNING TO DEVELOP ALONG MOUNTAINS...
FOOTHILLS AND PORTIONS OF PLAINS AS SHORTWAVE MOVES INTO WESTERN
COLORADO. RADAR SHOWING MOST OF THE ACTIVITY ACROSS NORTHERN
SECTIONS. DECENT SHEAR ACROSS EASTERN PLAINS AS SOUTHEAST SURFACE
WINDS INCREASE WITH SOUTHWEST TO WEST FLOW ALOFT. SURFACE DEWPOINTS
HAVE BEEN RUNNING AROUND 50 DEGREES. WITH TEMPERATURES AROUND 80
DEGREES...CAPE VALUES CURRENTLY BETWEEN 1000 AND 1500 J/KG. SEVERE
STORMS STILL POSSIBLE...WITH THE HIGHEST THREAT EAST OF FRONT RANGE
COMMUNITIES. HAIL AND WIND WILL BE THE MAIN THREAT...THOUGH A FEW
TORNADOES POSSIBLE GIVEN SHEAR PROFILE. SEVERE TSTM WATCH RECENTLY
BEEN HOISTED. WAVE TO SLIDE ACROSS AREA THIS EVENING...EXITING
THE STATE BY 06Z. CURRENT THINKING OF STORMS ENDING AT THAT TIME
STILL ON TRACK. COULD SEE SOME CLEARING OVERNIGHT WITH SUBSIDENCE...
AS NOTED BY CROSS SECTIONS. BUT SATELLITE SHOWING QUITE A BIT OF
MOISTURE UPSTREAM. ON WEDNESDAY...DEEP UPPER TROUGH TO MOVE INTO
GREAT BASIN WITH SOUTHWEST FLOW ALOFT STRENGTHENING ACROSS AREA.
MAIN CONCERN WILL BE INCREASING SURFACE WINDS DURING DAY. SANGESTER
FORECAST HIGH WIND MODELS SUGGEST WARNING CRITERIA FOR MOUNTAINS AND
FOOTHILLS DURING AFTERNOON. BUT CROSS SECTIONS SHOWING LACK OF
MOUNTAIN WAVE. IN ADDITION...MODELS SHOWING INCREASING QG ASCENT AS
UPPER TROUGH BEGINS TO SLIDE TOWARD COLORADO. FOR THESE REASONS...
WILL HOLD OFF ON ISSUING ANY HIGH WIND HILITE AT THIS TIME. ACROSS
PLAINS...MODELS SHOW WINDS AROUND 25 KTS AT 850 MB...WITH 45 KTS AT
700 MB. SHOULD BE QUITE WINDY DURING THE AFTERNOON...WITH POTENTIAL
FOR STRONGER WINDS MIXING TO SURFACE. BUT THIS MIXING MAY BE OFFSET
BY INCREASING ASCENT...SO WILL NOT ISSUE HIGH WIND WATCH. SHOULD SEE
HUMIDITY READINGS DROP INTO THE TEENS WITH DOWNSLOPE FLOW. SOME
THREAT OF A FIRE WEATHER CONCERN WITH THE LOW HUMIDTY AND GUSTY
WIND...BUT FUELS CURRENTLY MOIST SO THREAT APPEARS LOW. AS FOR
PRECIP CHANCES...INCREASING ASCENT AND MOISTURE SUPPORTS THE CHANCE
FOR AFTERNOON STORMS OVER THE MOUNTAINS. AS FOR PLAINS...BEST CHANCE
FOR ANY STORMS APPEARS TO BE ALONG FRONT RANGE AND PALMER DIVIDE WITH
LIFT...BUT MAY BE OFFSET BY DOWNSLOPE FLOW. DROPPED THE MENTION OF
PRECIP FARTHER EAST.

.LONG TERM...UNSEASONABLY COOL PACIFIC AIRMASS ASSOCIATED WITH A
DEEP MID/UPR LEVEL LONGWAVE TROUGH MAKES ITS WAY ACROSS COLORADO
WEDNESDAY NIGHT AND THURSDAY. MODELS SHOW A STG STANDUP PACIFIC COLD
FRONT MOVING THROUGH THE N-CNTRL MTNS WEDNESDAY NIGHT AND OUT ACROSS
NERN COLORADO EARLY THURSDAY MORNING. SEE STG MID-LEVEL CAA
OCCURRING OVER THE MTNS AFTER SHIFT TO W/NWLY FLOW WITH PASSAGE OF
THE 700-500 TROUGH AXIS AROUND 06Z/THU. NOT LONG AFTER CROSS
SECTIONS SHOW MOISTURE DEEPENING ALONG AND WEST OF THE CONTINENTAL
DIVIDE WITH MODEL SOUNDINGS INDICATING A SATURATED 750-500 LAYER
WEST OF THE DIVIDE. CROSS SECTIONS ALSO SHOW THE 0C ISOTHERM
LOWERING TO JUST BELOW 700MBS AND A MEAN WLY WIND COMPONENT OF 30KTS
AT MTN TOP LEVEL FOR 9 HOURS BEGINNING AT 06Z/THU. INPUTTING THIS
DATA INTO OUR LOCAL OROGRAPHIC SNOW MODEL CAME UP WITH SNOW TOTALS
ON MTN TOPS AND WEST FACING SLOPES ABOVE 9000 FEET IN THE 2-5 INCH
RANGE BY LATE THURSDAY MORNING. GREATEST UPWARD VERTICAL MOTION
APPEARS TO OCCUR FROM 06Z-12Z/THURSDAY ABOUT THE TIME THE NW QUAD OF
A 120KT SPD MAXIMA PASSES OVER THE AREA. MAY SEE SOME BLOWING SNOW
UP HIGH...MOST LIKELY ABOVE TIMBERLINE...BUT BELIEVE SNOW AMTS AND
THE SOMEWHAT LIMITED EXTENT OF BLOWING SNOW WILL NOT REQUIRE A
WINTER WEATHER HIGHLIGHT AT THIS TIME.

NEXT CONCERN HAS TO DO WITH THE THREAT OF STRONG BORA-TYPE WINDS ON
AND EAST OF THE FRONT RANGE LATE WEDNESDAY NIGHT INTO THURSDAY.
CROSS MTN WIND SPEEDS AT MTN TOP LVL BASED ON MODEL CROSS SECTIONS
IN THE 50-70KT RANGE. SEE STRONGEST WINDS OCCURRING ON EAST SLOPES
OF THE FRONT RANGE THURSDAY MORNING AND OUT ACROSS THE NERN PLAINS
MID-MORNING THROUGH LATE AFTERNOON DURING PERIOD OF MAX CAA. SEE
WLY WINDS OF 30-45KT WITH POSSIBLE GUSTS TO 60KTS IN THE FOOTHILLS.
ON THE PLAINS SEE NWLY WNDS OF 20-35KTS WITH GUSTS TO 45KTS DURING
PD OF STRONGEST CAA AND MID-LEVEL SUBSIDENCE. OVERALL SPEEDS
EXPECTED TO REMAIN BELOW HIGH WIND CRITERIA...BUT SHOULD WIND SPDS
INCREASE ON LATER MODEL RUNS MAY NEED TO DO SO...AT LEAST IN THE
FRONT RANGE ZONES.

AS FOR TEMPERATURES...WE/RE IN FOR ANOTHER BLAST OF UNSEASONABLY
COOL TEMPERATURES THROUGH FRIDAY. SEE LOWEST READINGS ON THURSDAY...
EVEN WITH STRONG SUBSIDENCE/DOWNSLOPE FLOW PRODUCING ALL OF THE
SUNSHINE EAST OF THE MTNS. WITHOUT THE SUNSHINE...MIGHT BE DEALING
WITH MAX TEMPS IN THE 50S...BUT IT IS JUNE...SO WILL GO WITH
LOWER/MID 60S ON THE PLAINS. SEE MTN TEMPS IN THE 30S/40S ON
THURSDAY AND LITTLE CHANGE ON FRIDAY AS THE MID/UPPER LEVEL TROUGH
WILL BE SLOW TO MOVE EAST OF THE AREA.

ON FRIDAY...GO ALOFT GOES NWLY BUT ENOUGH MOISTURE AND WEAK
INSTABILITY AROUND TO KEEP A CHANCE OF SHOWERS IN THE MTN ZONES AND
A SLIGHT CHANCE OF SHOWERS ON THE PLAINS...MAINLY UP ALONG THE NRN
BORDER. SHOULD SEE A GRADUAL RISE IN TEMPERATURES AS NOTED ABOVE.

SATURDAY AND BEYOND...SEE WARMER AND DRIER CONDITIONS SPREADING
ACROSS THE REGION AS FLOW ALOFT BECOMES SWLY AS A SHORTWAVE RIDGE
MOVES BY. SHOULD SEE TEMPERATURES RETURNING TO SEASONAL AVERAGES.

&&

.AVIATION...A FEW STORMS NEAR DIA THROUGH 03Z...WITH GUSTY WINDS
POSSIBLE. SURFACE WINDS TO INCREASE AFT 00Z WITH SPEEDS IN THE 15 TO
25 MPH RANGE. COULD SEE SOME GUSTS TO 35 MPH AFTER 18Z WEDNESDAY. A
FEW STORMS POSSIBLE ALONG FRONT RANGE AFTER 18Z...GUSTY WINDS COULD
AFFECT DIA.

&&

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

&&

DL/BAKER

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DENVER CO
1116 AM MDT TUE JUN 05 2007

COZ030>051-061200-
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-
1116 AM MDT TUE JUN 05 2007

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

.DAY ONE...TODAY AND TONIGHT

SCATTERED THUNDERSTORMS WILL DEVELOP ACROSS THE MOUNTAINS...
FOOTHILLS AND ALONG THE FRONT RANGE URBAN CORRIDOR THIS AFTERNOON.
THE STORMS WILL THEN MOVE EASTWARD ACROSS THE NORTHEAST PLAINS
THROUGH THE EVENING HOURS. SOME OF THE STORMS ACROSS THE PLAINS MAY
BECOME SEVERE WITH LARGE HAIL AND DAMAGING WINDS. IN ADDITION...AN
ISOLATED TORNADO OR TWO IS ALSO POSSIBLE. AT THIS TIME...IT APPEARS
THAT THE GREATEST THREAT FOR SEVERE WEATHER WILL BE EAST OF A
BRIGGSDALE TO KIOWA LINE AFTER 2 PM.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

GUSTY SOUTHWEST WINDS CAN BE EXPECTED ACROSS THE OUTLOOK AREA ON
WEDNESDAY IN ADVANCE OF A STRONG AND UNSEASONABLY COOL PACIFIC STORM
SYSTEM MOVING THROUGH THE GREAT BASIN. AREAS IN AND ALONG THE FRONT
RANGE AND PALMER DIVIDE AND OVER THE HIGH MOUNTAIN RIDGES WILL
LIKELY SEE THE STRONGEST WINDS. THIS WARM AND DRY WIND WILL PRODUCE
VERY LOW RELATIVE HUMIDITIES WHICH MAY INCREASE THE WILDLAND FIRE
DANGER. LAND MANAGERS SHOULD MONITOR THESE CONDITIONS CLOSELY. ON
THE NORTHEAST PLAINS OF COLORADO...STRONG SOLAR HEATING MAY ALSO
PRODUCE A FEW STRONG THUNDERSTORMS IN THE AFTERNOON AND EVENING.

WEDNESDAY NIGHT AND THURSDAY...THIS POTENT PACIFIC STORM SYSTEM WILL
MOVE ACROSS COLORADO...BRINGING WITH IT MUCH COOLER TEMPERATURES...
HIGHER HUMIDITIES AND A BETTER CHANCE FOR SHOWERS. IN THE HIGH
COUNTRY TEMPERATURES MAY BECOME COLD ENOUGH FOR SNOW...WITH THE SNOW
LEVEL POSSIBLY DOWN TO AS LOW AS 9000 FEET. EAST OF THE MOUNTAINS...
LOOK FOR BLUSTERY WEST TO NORTHWEST WINDS TO DEVELOP AFTER PASSAGE
OF A STRONG COLD FRONT LATE WEDNESDAY NIGHT. IN AND NEAR THE
FOOTHILLS...WIND GUSTS OF 25 TO 40 MPH MAY OCCUR WITH SOME GUSTS TO
65 MPH. WINDS ARE EXPECTED TO SUBSIDE IN MOST AREAS THURSDAY NIGHT.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED AFTER 1 PM OVER NORTHEAST COLORADO.

D-L/BAKER