Tornado Warning 65, NWS Denver/Boulder, CO

000 
WWUS55 KBOU 172254
SVSBOU

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
454 PM MDT FRI JUL 17 2009

COC121-172303-
/O.CAN.KBOU.TO.W.0065.000000T0000Z-090717T2315Z/
WASHINGTON CO-
454 PM MDT FRI JUL 17 2009

...THE TORNADO WARNING FOR SOUTHEASTERN WASHINGTON COUNTY IS 
CANCELLED...

THE THUNDERSTORM THAT PROMPTED THE WARNING HAS WEAKENED AND IS NO 
LONGER EXPECTED TO PRODUCE SEVERE WEATHER AND WILL EXIT THE AREA IN 
THE NEXT FIVE MINUTES. 

A TORNADO WATCH REMAINS IN EFFECT UNTIL 700 PM MDT FRIDAY EVENING FOR
NORTHEASTERN COLORADO.

LAT...LON 3956 10280 3956 10307 3979 10318 3988 10298
      3970 10279 3957 10279
TIME...MOT...LOC 2253Z 329DEG 27KT 3959 10289

$$
KRIEDERMAN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
158 PM MDT FRI JUL 17 2009

.SHORT TERM...TORNADO WATCH IN EFFECT IN UNTIL 7 PM. AN UNSTABLE
AIRMASS HAS DEVELOPED OVER THE PLAINS THIS AFTERNOON WITH CAPES OF
1500 TO 3000 J/KG. DEW POINTS WILL REMAIN IN THE 50S ACROSS THE
EASTERN PLAINS...BUT OVER FRONT RANGE DEW POINTS WILL FALL INTO THE
30S AND 40S AS DRIER AIR ALOFT MIXES DOWN. SEEING A SHORT WAVE OVER
EASTERN WYOMING AT THIS TIME. AS THIS WAVE PUSHES SOUTHEAST DUE TO
THE NORTHWEST FLOW ALOFT...IT WILL CONTINUE TO TRIGGER
THUNDERSTORMS. THERE WILL BE ENOUGH SHEAR FOR SUPER CELL
THUNDERSTORMS. BECAUSE OF THE STRONG INSTABILITY...LARGE HAIL WILL
BE THE GREATEST THREAT. THE THREAT FOR TORNADOES WILL BE LOW...BUT
CANT BE RULED OUT DUE TO LOCAL ENHANCEMENT OF LOW LEVEL SHEAR
BECAUSE OF OUTFLOW BOUNDARIES AND SOMEWHAT LOW LCLS OVER THE EASTERN
PLAINS. THE DENVER METRO AREA MAY SEE A FEW STORMS...BUT THE THREAT
FOR SEVERE STORMS IS LOWER DUE TO THE DRIER AIR MIXING DOWN AND THE
SHEAR IS LESS. THE THUNDERSTORMS WILL DECREASE THIS EVENING AS THE
AIRMASS STABILIZES.

WILL KEEP THUNDERSTORMS IN THE FORECAST FOR LATE TONIGHT AND
SATURDAY MORNING OVER THE FAR EASTERN PLAINS. A 70+ KNOT JET IS
FORECASTED TO MOVE OVER THE AREA. THIS MAY PRODUCE ENOUGH LIFT FOR
THUNDERSTORMS TO CONTINUE THROUGH THE NIGHT AND MORNING...SIMILAR TO
TODAY OVER NEBRASKA.

ANOTHER ROUND OF ISOLATED TO SCATTERED THUNDERSTORMS WILL FORM
SATURDAY AFTERNOON. CAPES WILL BE 1000-2500 J/KG BY AFTERNOON. SHEAR
WILL BE A LITTLE LESS THAN TODAY BUT ENOUGH FOR A FEW SUPER CELLS TO
FORM. WITH THIS SAID...MAY SEE A SOME SEVERE STORMS AGAIN WITH LARGE
HAIL AND DAMAGING WINDS. MOISTURE WILL MIGRATE SLIGHTLY WESTWARD
SATURDAY SO THE CHANCES FOR STORMS ALONG THE URBAN CORRIDOR AND
FOOTHILLS WILL BE GREATER THAN PREVIOUS DAYS. AIRMASS TEMPERATURE
CHANGES VERY LITTLE SO HIGHS WILL BE CLOSE TO TODAYS READINGS.

.LONG TERM...NORTHWEST FLOW WILL DOMINATE THROUGH MOST OF THE
EXTENDED PERIOD AS MODELS SHOW A STRONG UPPER RIDGE CAMPED OUT OVER
THE FOUR CORNERS REGION. IN THIS POSITION MUCH OF THE SUBTROPICAL
MOISTURE FLOWING UP THRU MEXICO WILL BE DEFLECTED WESTWARD AWAY FROM
THE FCST AREA. SOME OF THIS MOISTURE MAY STILL CIRCULATE ALONG THE
FRINGE OF THE UPPER RIDGE AND OVER NERN COLORADO FROM TIME TO TIME.
PINNING DOWN THE TIMING OF THESE MOISTURE SURGES WILL BE DIFFICULT.
HOWEVER MODELS SHOW A FAIR MOUNT OF LOW/MID-LEVEL MOISTURE ARRIVING
WITH A COLD/COOL FRONT MONDAY NIGHT. UNTIL THAT TIME...SHOULD STILL
SEE JUST ENOUGH LOW LEVEL MOISTURE AROUND TO SUPPORT AT LEAST
ISOLATED AFTERNOON/EVENING T-STORM COVERAGE ON SUNDAY...WITH THE
BETTER CAPES...BULK LAYER SHEAR AND MOISTURE OUT ACROSS THE FAR NERN
PLAINS. CAN/T RULE OUT AN ISOLATED SUPER CELL CLOSE TO THE NERN
CORNER LATE IN THE DAY. SHOULD SEE SFC TEMPS ON SUNDAY 2-3C ABOVE
THOSE ON SATURDAY WITH A RETURN TO A SELY BOUNDARY LAYER FLOW.

ON MONDAY...DAY SHOULD START OUT DRY AND WARM. WITH THE MOISTURE
ALONG THE FRONT RANGE BEING FLUSHED OUT BY A W-NWLY PRE-FRONTAL
FLOW. MODELS GENERALLY AGREE ON DROPPING A COLD FRONT SOUTH THRU
NERN COLORADO BY AROUND MIDDAY. THE POST-FRONTAL ENVIRONMENT DOES
NOT LOOK ALL THAT MOIST AND UNSTABLE...EXCEPT PERHAPS OUT ACROSS THE
NERN QUAD OF THE CWFA WHERE THE PASSAGE OF A WEAK SHORTWAVE MAY BE
ALL THAT/S NECESSARY TO SET OFF SCATTERED LATE DAY T-STORMS...ONE OR
TWO CAPABLE OF LARGE HAIL. MONDAY MAX TEMPERATURES SLIGHTLY LOWER
THAN THE DAY BEFORE...AND POSSIBLY COOLER IF THE COLD FRONT ARRIVES
SOONER THAN EXPECTED.

TUESDAY...LOOKS LIKE A PROVERBIAL POST-FRONTAL DAY TWO SET-UP.
E-NELY FLOW IN THE MORNING TURNS SELY IN THE AFTERNOON WHICH HELPS
TO DRIVE A PLUME OF LOW-LEVEL MOISTURE UP THE FRONT RANGE. GFS SHOW
PW VALUES STEADILY RISING THRU THE DAY WITH MAX VALUES OVER THE
PALMER DVD...SRN FRONT RANGE FOOTHILLS AND PARK COUNTY AROUND
00Z/WED. LIGHTER NWLY FLOW ALOFT MAY INCREASE THE RISK OF HEAVY
RAINFALL IN THESE AREAS...ESPLY DURING THE LATE AFTERNOON AND
EVENING HOURS. SMALL HAIL ALSO A PRETTY GOOD BET. COOLER
TEMPERATURES ON TUESDAY WILL FURTHER INCREASE THE CHANCE FOR HEAVY
RAINERS.

FOR THE REMAINDER OF THE EXTENDED PD...SEE A TREND TOWARDS DRIER AND
WARMER CONDITIONS AS MEDIUM RANGE MODELS SUGGEST AN EASTWARD SHIFT
IN THE UPPER RIDGE...WHICH EVENTUALLY MAY ALLOW FOR A RESUMPTION OF
THE SOUTHWEST MONSOON. TIME WILL TELL.

.AVIATION...THUNDERSTORMS WILL CONTINUE TO DEVELOP ACROSS THE AREA
THROUGH 00Z. GUSTY OUTFLOW WINDS WILL LIKELY AFFECT THE AIRPORTS
BETWEEN 21Z AND 01Z. THERE IS ABOUT A 40 PERCENT CHANCE OF A
THUNDERSTORM MOVING OVER KDEN...KAPA AND KBJC. IF A THUNDERSTORM
MOVES OVER AN AIRPORT HEAVY RAIN...HAIL UP TO 1 INCH IN DIAMETER AND
OUTFLOW WINDS TO 40 KNOTS WILL BE POSSIBLE. THUNDERSTORM ACTIVITY IS
EXPECTED TO DIE OFF AFTER 02Z. LOW CLOUDS WILL FORM AGAIN OVER THE
EASTERN PLAINS AND ARE EXPECTED TO REMAIN JUST EAST OF KDEN. LIGHT
DIURNAL WINDS WILL PREVAIL EXCEPT NEAR THUNDERSTORMS. ANOTHER ROUND
OF THUNDERSTORMS WILL DEVELOP SATURDAY AFTERNOON.

&&

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

MEIER/BAKER

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DENVER CO
1113 AM MDT FRI JUL 17 2009

COZ030>051-181200-
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-
1113 AM MDT FRI JUL 17 2009

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

.DAY ONE...TODAY AND TONIGHT

THERE WILL BE A CHANCE OF THUNDERSTORMS OVER THE PLAINS THIS
AFTERNOON AND EVENING WITH A SLIGHT CHANCE OF THUNDERSTORMS IN AND
NEAR THE FOOTHILLS.  A FEW STORMS COULD BE SEVERE OVER THE PLAINS
WITH HAIL TO ONE INCH IN DIAMETER ALONG WITH WIND GUSTS TO 60 MPH.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THERE WILL BE A CHANCE FOR AFTERNOON AND EVENING THUNDERSTORMS OVER
THE PALMER DIVIDE AND NEARBY AREAS ON SATURDAY...WITH A LESSER
CHANCE ELSEWHERE. SUNDAY THROUGH THE MIDDLE OF NEXT WEEK...THE BEST
CHANCE FOR LATE DAY THUNDERSTORMS...ALBEIT A SMALL ONE...WILL SHIFT
TO THE FRONT RANGE FOOTHILLS AND SOUTH PARK AS WELL AS OVER THE
PALMER DIVIDE. THE LIKELIHOOD FOR SEVERE WEATHER SHOULD REMAIN LOW
AS MUCH OF THE AREA WILL REMAIN UNDER THE INFLUENCE OF A STRONG AND
VERY WARM UPPER LEVEL HIGH PRESSURE RIDGE.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT.

MEIER/BAKER

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
237 PM MDT FRI JUL 17 2009

...TORNADO WATCH IN EFFECT FOR NORTHEAST COLORADO...

A TORNADO WATCH IS IN EFFECT FOR MUCH OF NORTHEAST COLORADO THROUGH
7 PM THIS EVENING INCLUDING ADAMS AND ARAPAHOE COUNTIES.  THE THREAT
OF SEVERE WEATHER IS MUCH GREATER TO THE EAST OF METRO DENVER IN THE
EASTERN HALF OF ADAMS AND ARAPAHOE COUNTIES.  THE TORNADO WATCH DOES
NOT INCLUDE DENVER COUNTY OR DENVER INTERNATIONAL AIRPORT.

RTG