Severe Thunderstorm Warning 63, NWS Denver/Boulder, CO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
315 AM MDT SAT JUN 19 2004

.SHORT TERM...STILL SOME ONGOING CONVECTION ACROSS PORTIONS OF
EASTERN CO ATTM. MUCH OF THE ACTIVITY HAS ACTUALLY INCREASED DUIRNG
THE PAST HOUR AND SEEMS DUE TO AN UPPER LEVEL WAVE MOVING NORTHEAST
INTO SERN CO ALONG WITH PRE-EXISTING OUTFLOW BOUNDARIES MOVING
NORTHWARD. BESIDES THE CONVECTION...LOW LVL MSTR STILL PLENTIFUL
ACROSS ERN CO BUT FRONT RANGE TERMINAL SITES SHOWING STRATUS
BREAKING UP TO SOME EXTENT AS SERLY LOW LVL FLOW INCREASES AND
DOWNSLOPES OFF THE PALMER DIVIDE. FORECAST SOUNDINGS INDICATE LOW
LVL MSTR BECOMES MORE SHALLOW TOWARDS DAYBREAK WITH DRYING AND
SUBSIDENT AIRMASS ALOFT. THIS MAY LEAD TO SOME DENSE FOG BUT
CONFIDENCE LOW ABOUT HOW WIDESPREAD THIS MAY BE...ESP ACROSS DENVER
AREA WITH SE FLOW WHERE FOG WOULD PROBABLY NOT BE AS DENSE OR
WIDESPREAD. BETTER FOG CONDITONS MAY END UP OVER THE PLAINS AND
ACROSS EASTERN LARIMER AND NORTHWEST WELD COUNTY. ONGOING CONVECTION
ON THE PLAINS ALSO LIKELY TO DISRUPT STRATUS/FOG MAKEUP AS WELL.

MAIN CONCERN TODAY WILL BE FOG/STRATUS DISSIPATION AND ONSET OF AFTN
CONVECTION...IF ANY? ETA BUFFER SOUNDINGS INDICATE STRONG CAPPING
INVERSION AT 750 MB WILL SLOWLY ERODE BY 00Z SUN WITH SFC HEATING
THIS AFTN. A LITTLE SUSPECT WITH THIS AMOUNT OF WARMING AS 700MB
TEMPS RISE TO +12C. BUT THIS MAY NOT BE TOO FAR OFF WITH THESE TYPES
OF READINGS UPSTREAM. MAY GET SOME HELP ALOFT WITH PASSING JET
STREAK AND DEVELOPMENT OF DENVER CYCLONE WITH THE STRENGTHENING S-SE
LOW LV FLOW AS THE SURFACE HIGH FINALLY SHIFTS SOUTHEAST INTO THE
CENTRAL PLAINS. EXPECT STORM INITIATION WILL DEVELOP ALONG
CONVERGENCE WITH DEN CYCLONE AND ACROSS HIGHER TERRAIN OF PALMER
DIVIDE AND CYS RIDGES. FURTHER EAST...MUCH OF THE CONVECTION WILL
WAIT UNTIL TNT WITH INCREASING LOW LVL JET AND STORMS BEGIN TO MOVE
OFF HIGHER TERRAIN AREAS. WITH THAT SAID...WILL TRY AND FOCUS THE
HIGHER POPS OVER HIGHER TERRAIN...WHILE OTHER PLACES TODAY WILL
LOWER POPS TO VARYING DEGREES OF ISOLD COVERAGE ACROSS THE BOARD.
STORMS THAT DO DEVELOP WILL HAVE THE POTENTIAL TO REACH SEVERE
LIMITS WITH CAPES BETWEEN 1500-2000J/KG AND SUFFICIENT LOW LVL SHEAR
AND 40-50KT FLOW AT MID LVLS. ISOLD WEAK TORNADOES ALSO POSSIBLE
ALONG CONVERGENCE LINE WITH DENVER CYCLONE.

LOOKS LIKE ANOTHER SURGE TRYS TO SLIP INTO NERN CO LATE TNT WITH
SOME LOW LVL MSTR RETURNING AND POTENTIAL FOR MORE FOG/STRATUS
ACROSS THE EASTERN PLAINS. WILL AT LEAST KEEP SOME CLOUDS IN LATE
TNT FOR NOW.

.LONG TERM DISCUSSION...ON SUNDAY A WEAK WESTERLY FLOW WILL BE OVER
COLORADO WITH AN ELONGATED W-E TROF AXIS STRETCHING OVER THE PACIFIC
NORTHWEST.  THE ETA/GFS SHOW MORE ENERGY MOVING ACRS COLORADO BY
SUNDAY AFTERNOON WHICH COULD AID IN THUNDERSTORM DEVELOPMENT. AT THE
SFC THE MDLS INDICATE A WEAK SFC LOW WILL FORM OVER SERN CO LATE
SATURDAY NIGHT. AS IT DOES...A LOW LEVEL EASTERLY FLOW DEVELOPS
WHICH WILL USHER IN INCREASING MSTR FM THE EAST FOR A RETURN
ENGAGEMENT OF MORNING STRATUS AND FOG. IF THIS OCCURS THAN IT COULD
BE ANOTHER INTERESTING AFTERNOON IF LOW LEVEL MOISTURE CAN AVOID
MIXING OUT. SUNDAY NIGHT...ANOTHER CANADIEN COLD FRONT WILL MOVE
THROUGH NORTHEASTERN COLORADO AFTER 06Z...AS MORE ENERGY ASSOCIATED
WITH A WEAK DISTURBANCE ALF MOVES ACRS THE STATE. MORE OF THE SAME
MONDAY AND MONDAY NIGHT WITH MSTR...UPSLOPE AND JUST ENOUGH WARMING
TO FIRE OFF MORE SHOWERS AND THUNDERSTORMS...MAINLY ALONG THE FRONT
RANGE FOOTHILLS AND PALMER DIVIDE...WHERE THE LOW LEVEL THETA-E
RIDGE WILL BE IN PLACE. THE LATEST GFS SHOW YET ANOTHER SURGE OF
HIGH PRESSURE SLIDING THROUGH THE NORTHEASTERN PLAINS TUESDAY
NIGHT.  SEE NO REASON TO CHANGE ANYTHING BEYOND TUESDAY AT THIS TIME
WITH A SLIGHT CHC OF AFTN/EVENING THUNDERSTORMS EACH DAY.

&&

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

ENTREKIN/COOPER

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DENVER CO
1102 AM MDT SAT JUN 19 2004

COZ030>051-201200-
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-
1102 AM MDT SAT JUN 19 2004

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

.DAY ONE...TODAY AND TONIGHT

SCATTERED THUNDERSTORMS WILL CONTINUE TO DEVELOP ACROSS THE
MOUNTAINS...MOVING ONTO THE PLAINS DURING THE AFTERNOON.  IN
ADDITION...THUNDERSTORMS COULD ALSO DEVELOP ALONG A CONVERGENCE LINE
EXTENDING FROM EASTERN ADAMS COUNTY SOUTHWESTWARD INTO EASTERN
DOUGLAS COUNTY.  SOME STORMS COULD BECOME SEVERE ACROSS THE DENVER
AREA AND STRETCHING SOUTH AND EAST ACROSS THE PALMER DIVIDE.  A FEW
STORMS COULD ALSO DEVELOP AND BECOME SEVERE OVER THE HIGHER TERRAIN
ALONG THE CHEYENNE RIDGE.  LARGE HAIL AND DAMAGING WINDS WILL BE THE
MAIN THREAT.  A SHORT-LIVED TORNADO CANNOT BE RULED OUT...ESPECIALLY
ALONG THE CONVERGENCE LINE EAST AND SOUTH OF DENVER.

THE RECENT RAINFALL HAS SATURATED THE GROUND ACROSS MUCH OF THE AREA.
ADDITIONAL RAIN COULD CREATE LOCALIZED FLOODING...ESPECIALLY ALONG
THE FOOTHILLS AND ACROSS SOUTHERN DOUGLAS COUNTY IN THE HAYMAN BURN
AREA.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

SOME THUNDERSTORM ACTIVITY IS EXPECTED AGAIN SUNDAY AFTERNOON SINCE
THE ATMOSPHERE WILL REMAIN RELATIVELY MOIST.  INSTABILITY WILL BE
MORE FAVORABLE FOR THUNDERSTORM DEVELOPMENT ON THE PLAINS TOMORROW
AND THE BEST CHANCE FOR SEVERE WEATHER WILL LIKELY OCCUR EAST OF A
AKRON TO LIMON LINE AFTER 1 PM.  A STRONG COLD FRONT WILL MOVE INTO
THE AREA SUNDAY NIGHT OR MONDAY MORNING.  THIS WILL LEAD TO COOLER
WEATHER ONCE AGAIN WITH STRATIFORM PRECIPITATION POSSIBLE ALONG THE
FRONT RANGE AND FOOTHILLS FOR MONDAY.  IN ALL...ENOUGH MOISTURE WILL
CONTINUE TO EXIST IN THE AREA FOR SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS ACROSS THE ENTIRE AREA THROUGH FRIDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED AFTER 2 PM TODAY AND CONTINUING
THROUGH THIS EVENING.