Flash Flooding and Hail in Colorado, June 20, 2002

NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER COLORADO
252 PM MDT THU JUN 20 2002

PLENTY OF MOISTURE AND INSTABILITY AVAILABLE AGAIN FOR ANOTHER
ACTIVE AFTN AND EVE. 1045AM SPSDEN PRETTY MUCH COVERS THE SITUATION
FOR THE NORTHEAST AND WONT REPEAT THE MESOSCALE DETAILS OTHER THAN
IT LOOKS ACTIVE AGAIN AS SCT STORMS LOOK TO FIRE OVER THE HIGHER
TRRN THIS AFTN AND THEN INTENSIFY OVER THE PLAINS INTO THE EVENING
HRS. WILL KEEP THE CURRENT MENTION OF SEVERE STORMS IN THE
APPROPRIATE ZNS. WILL PLAN ON THE AREA GRADUALLY CLEARING OUT
OVERNGT BUT WILL LEAVE OUT ANY MENTION OF FOG ATTM AS MESOETA SFC
RHS BEGIN TO DRY OUT AFTER 09Z WITH LOW LVL FLOW TRENDING
SOUTHWESTERLY OR AT LEAST BCMG GOOD DRAINAGE. IF HEAVY RAIN AND/OR
HAIL DUMPS OVER A CERTAIN AREA THEN PERHAPS SOME LOCAL AREAS OF FOG
ALONG THE PLATTE MAY BE NEEDED LATER. FOR FRIDAY SOME DRYING BEGINS
OVR THE AREA WITH SOUTHWEST FLOW DEVLPG THROUGHOUT MUCH OF THE
ATMSPHR BUT SFC SOUTH TO SOUTHEAST WINDS CONT OVR THE PLAINS. FCST
CAPE VALUES FOR FRIDAY AFTN ARE ROUGHLY A THIRD OF TDYS PROJECTED
VALUES WITH A BIT MORE CIN TO FIGHT THROUGH. WILL KEEP CURRENT ISOLD
AFTN/EVE POPS FROM A BIT MORE MID LVL WARMING. FURTHER DRYING EAST
OF THE DIVIDE OCCURS FOR SAT AS STRONGER 850 AND 700 MB WINDS BOTH
GO SOUTHWESTERLY FROM THE SHORTWAVE EJECTING OUT OF THE DESERT
SOUTHWEST TO THE NORTHEAST. THERE IS SOME WEAK QG ASCENT WITH THE
SHORTWAVE EARLY SATURDAY BUT IT LOOKS AS IF TSTORMS WILL BE HIGH
BASED AND GUSTY DURING THE AFTN AND ESPECIALLY IN EVE ON THE BACK
SIDE OF SHORTWAVE. MDLS ALSO HINT AT A LEESIDE SFC TROUGH SAT AND
THEN STRENGTHENING INTO THE EARLY HRS OF SUNDAY. THIS FEATURE OF
STRENGTHENING WESTERLY WINDS MAY REFLECT THE UPPER LVL FRONT OR TROF
AXIS ASSOCIATED WITH THE EXITING SHORTWAVE. BY MIDDAY SUNDAY THE
UPPER RIDGE BEGINS TO STRENGTEN FURTHER OVR THE SOUTHWEST USA WITH
HIGHER HEIGHTS NOSING INTO THE SOUTHERN HALF OF THE STATE. AVN SHOWS
EASTERLY WINDS DEVLOPING LATE IN THE DAY BUT WILL DISCOUNT THAT ATTM
AND KEEP THE SUNDAY DRY.

LATER PERIODS...MONDAY THROUGH THURSDAY...RIGHT WITH CLIMATOLOGY IT
LOOKS LIKE THE OFFICIAL MARKING OF THE END OF SPRING IS RIGHT ON
SCHEDULE FOR LATE JUNE WITH A DROP OFF OF PRECIP AND WARMER TEMPS.
THE MRF IS PLANNING ON A MASSIVE RIDGE DOMINATING THE WESTERN 2/3RDS
OF THE NATION BY NEXT WEEK. TOUGH TO PINPOINT ANY FOCUS THAT WOULD
PROVIDE PRECIPITATION UNDER STRONG RIDGING AND WOULD RATHER KEEP ALL
DAYS IN THE EXTENDED DRY IN THE DROUGHT. FREDIN

.DEN...NONE

COZ030>051-202000-

HAZARDOUS WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER COLORADO
1045 AM MDT THU JUN 20 2002

THIS OUTLOOK PERTAINS TO THE FOLLOWING COLORADO COUNTIES

ADAMS     ARAPAHOE  BOULDER     BROOMFIELD  CLEAR CREEK  DENVER
DOUGLAS   ELBERT    GILPIN      GRAND       JACKSON      JEFFERSON
LARIMER   LINCOLN   LOGAN       MORGAN      PARK         PHILLIPS
SEDGWICK  SUMMIT    WASHINGTON  WELD

SYNOPSIS...SOUTHEAST WINDS OVER THE PLAINS HAVE INITIATED A RETURN
FLOW OF LOW LEVEL MOISTURE AGAINST THE EAST SLOPES OF THE MOUNTAINS
TODAY...WHICH WILL KEEP SURFACE DEWPOINTS IN THE 50S AND EVEN THE
LOWER 60S EAST OF THE MOUNTAINS.  THE LOW LEVEL FLOW WILL LIKELY
CREATE A DENVER MESOCYCLONE BY EARLY AFTERNOON.  THIS TOGETHER WITH
AN UPPER LEVEL DISTURBANCE AT AROUND MAXIMUM HEATING TIME WILL KEEP
THE AIR MASS VERY UNSTABLE.  THUS...ALL OF THE INGREDIENTS ARE IN
PLACE FOR A TYPICAL POST-FRONTAL DAY 2 SCENARIO FOR AN OUTBREAK OF
SEVERE WEATHER ACROSS THE URBAN CORRIDOR AND NORTHEASTERN PLAINS OF
COLORADO THIS AFTERNOON AND EVENING.

SCATTERED SHOWERS AND THUNDERSTORMS WILL FORM OVER THE FRONT RANGE
MOUNTAINS AND EASTERN FOOTHILLS DURING THE EARLY AFTERNOON.  BY MID
AFTERNOON...THESE STORMS WILL SPREAD TO THE NORTHEAST OVER THE URBAN
CORRIDOR AND NORTHEASTERN PLAINS ON SOUTHWEST WINDS ALOFT.  A NUMBER
OF THESE THUNDERSTORMS WILL BECOME SEVERE PRODUCING LARGE HAIL AND
DAMAGING WINDS DURING THE LATE AFTERNOON AND EARLY EVENING.  ADEQUATE
SHEAR WILL BE PRESENT FOR ONE OR TWO OF THE STORMS TO PRODUCE
TORNADOES.  ALL OF THE STORMS WILL PRODUCE DANGEROUS CLOUD TO GROUND
LIGHTNING.

SPOTTER ACTIVATION WILL BE REQUIRED BY MID AFTERNOON.

OUTLOOK FOR FRIDAY...WARMER AND DRIER WITH ISOLATED LATE DAY SHOWERS
AND THUNDERSTORMS.

GARD...WFO BOULDER