Hail and Damaging Winds in Colorado, June 14, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
345 AM MDT SUN JUN 14 2009

.SHORT TERM...MAIN CONCERN AGAIN IS THE SEVERE WEATHER POTENTIAL
ACROSS THE NORTHEAST PLAINS FOR THIS AFTERNOON AND EVENING. TODAY IS
NOT AS CLEAR CUT...AS SOME DRIER AIR HAS MIXED DOWN IN THE SOUTHWEST
FLOW ALONG THE FRONT RANGE. WATER VAPOR IMAGERY SHOWING MUCH OF THE
CWA IN A DRY SLOT REGIME ATTM IN ADVANCE OF THE NEXT WAVE ACROSS
SOUTHERN CALIFORNIA. INTEGRATED PW FROM GPS INDICATED WE HAVE LOST
ALMOST A HALF INCH OF WATER IN THE LAST 24 HOURS. SURFACE DEWPOINTS
HAD LOWERED TO AROUND 40 WITH INCREASING DRAINAGE WINDS...HOWEVER
COMING BACK UP AGAIN WITH WEAK SURGE WORKING ITS WAY SOUTHWARD
FOLLOWING CONVECTION IN WYOMING.

RUC/NAM CROSS SECTIONS SHOW THIS DRIER AIR WILL HOLD IN THROUGH
MIDDAY.  HOWEVER...THE NEXT UPPER LEVEL DISTURBANCE ACROSS SRN
CALIFORNIA WILL MOVE INTO COLORADO LATER THIS AFTERNOON WITH
INCREASED MOISTURE LEVELS AGAIN. FORECAST SOUNDINGS SHOW MORE HIGH
BASED CONVECTION OVER THE FRONT RANGE WITH SURFACE BASED CAPES FROM
500-900J/KG WITH TEMPS CLOSE TO 80 DEGREES AND DEWPOINTS RANGING
FROM 40-45. FURTHER EAST ON THE FAR NORTHEAST PLAINS...THERE IS A
FAIRLY SUBSTANTIAL CAP IN PLACE AROUND 750MB WHICH NEVER QUITE
DISSOLVES. REALITY WOULD PUT HI TEMPS IN THE UPPER 70S WITH MID 50
DEWPOINTS WHICH RESULTS IN CAPES IN EXCESS OF 2000J/KG WITH STILL
SOME CIN AROUND. GIVEN STRENGTH OF EJECTING WAVE FROM SRN
CA...EXPECT THUNDERSTORMS TO DEVELOP BY LATE IN THE DAY AND ERODE
THE CAP. THE LOW LVL SHEAR IS NOT QUITE AS STRONG TODAY SO WOULD
EXPECT A LOWER TORNADO THREAT. OVERALL...EXPECT THE SEVERE WEATHER
THREAT WOULD BE GREATEST EAST OF THE URBAN CORRIDOR WITH LARGE HAIL
UP TO 2 INCH DIAMETER THE MAIN IMPACT. WILL PUT THE HIGHER
POPS/MENTION SEVERE EAST OF THE DENVER AREA.

.LONG TERM...MEAN LONG WAVE TROUGH ALONG THE WEST COAST DEEPENS AS
IT CONTINUES TO DIG DURING THE EARLY PART OF THE WEEK. MODELS SHOW
THIS UNUSUALLY STRONG TROUGH CLOSING OFF AT 500MB OVER SOUTHERN
CALIFORNIA BY TUESDAY. AS IT DOES THIS A RIDGE FORMS DOWNSTREAM OVER
THE EASTERN GREAT BASIN ON TUESDAY PRODUCING NEAR ZONAL FLOW OVER
COLORADO. AS THE WESTERN TROUGH CONTINUES TO MIGRATE SOUTHWARD THE
GREAT BASIN RIDGE SLOWLY MIGRATES EASTWARD OVER COLORADO BY
WEDNESDAY. AS A RESULT SHOULD SEE A GRADUAL DECREASE IN DAYTIME
CONVECTION ACROSS THE FCST AREA AS TEMPS WARM A FEW DEGS EACH DAY.
BY WEDNESDAY COULD SEE MAX TEMPS IN THE MID/UPR 80S ON THE PLAINS
WITH ONLY A SLIGHT CHANCE OF AFTERNOON AND EVENING T-STORMS.

LATER IN THE WEEK...GFS SHOWS THE WESTERN TROUGH CUTTING OFF FROM
THE MEAN FLOW ALOFT. AS THIS HAPPENS A RATHER VIGOROUS MID-LEVEL
TROUGH DROPS OUT OF THE PACIFIC NORTHWEST AND OVER THE CNTRL ROCKY
MTN REGION. ECMWF DIFFERS FM THE GFS IN THAT IT SHOWS THE WRN TROUGH
MOVING ONSHORE IN ONE PIECE AND ACROSS THE GREAT BASIN ON WEDNESDAY
AND THURSDAY. ASSUMING THE GFS IS CORRECT SHOULD COOLING ACROSS THE
FCST AREA WITH TEMPERATURES RETURNING TO NEAR NORMAL IF NOT A FEW
DEGS BELOW NORMAL THURSDAY AND FRIDAY. SHOULD ALSO SEE A RETURN TO
DAILY ROUND OF SCATTERED AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS.

&&

.AVIATION...SFC WINDS SHIFTING NORTHERLY WITH SOME PATCHES OF
FOG/STRATUS EARLY AM AT LOCAL AIRPORTS. THUNDERSTORM WINDOW TODAY
FROM 22Z-01Z WITH A MORE SEVERE WEATHER THREAT EAST OF THE DENVER
AREA. EXPECT MAIN IMPACT WILL BE GUSTY WINDS OT 40KT...BRIEF HEAVY
RAIN AND SMALL HAIL.

&&

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

ENTREKIN/BAKER

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DENVER CO
1110 AM MDT SUN JUN 14 2009

COZ030>051-151200-
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-
1110 AM MDT SUN JUN 14 2009

...SEVERE THUNDERSTORMS POSSIBLE AGAIN ACROSS THE NORTHEAST PLAINS
THIS AFTERNOON AND EVENING...

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

.DAY ONE...TODAY AND TONIGHT

SCATTERED THUNDERSTORMS WILL AGAIN DEVELOP OVER THE MOUNTAINS AND
ADJACENT PLAINS EARLY THIS AFTERNOON AND THEN SPREAD FURTHER EAST
THROUGH THE EVENING HOURS.  A SLIGHTLY DRIER AIRMASS HAS MOVED INTO
THE AREA EARLY THIS MORNING...HOWEVER ANOTHER UPPER LEVEL WEATHER
DISTURBANCE WILL MOVE OVER THE MOUNTAINS AND EASTERN PLAINS THIS
AFTERNOON WITH A RETURN OF MOISTURE AND INSTABILITY.

ALL OF THE NORTHEAST PLAINS HAS A CHANCE OF SEVERE THUNDERSTORMS
THIS AFTERNOON...BUT THE HIGHEST CHANCES FOR SEVERE THUNDERSTORMS
WILL BE EAST OF THE URBAN CORRIDOR AND ALONG THE PALMER DIVIDE WHERE
DEEPER MOISTURE RESIDES.  THE STRONGEST STORMS MAY PRODUCE LARGE
HAIL UP TO 2 INCHES IN DIAMETER ALONG WITH DAMAGING WINDS.  WEAKER
SURFACE WINDS THIS MORNING HAVE REDUCED THE TORNADO THREAT TODAY...
BUT AN ISOLATED WEAK TORNADO IS STILL POSSIBLE.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

MORE SHOWERS AND THUNDERSTORMS ARE EXPECT ON MONDAY. SOME
THUNDERSTORMS WILL PRODUCE HAIL AND HEAVY RAIN. CHANCES FOR
THUNDERSTORMS DECREASE TUESDAY AND WEDNESDAY AS WARMER AND DRIER
CONDITIONS ASSOCIATED WITH A HIGH PRESSURE RIDGE MOVE OVER THE
STATE. BY THURSDAY...THUNDERSTORM CHANCES INCREASE AGAIN AS A LOW
PRESSURE SYSTEM MOVES OUT OF THE PACIFIC NORTHWEST AND ACROSS
COLORADO BRINGING WITH IT SLIGHTLY COOLER TEMPERATURES.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED AFTER 2 PM.

DANKERS/MEIER