Severe Thunderstorm Warning 89, NWS Denver/Boulder, CO

NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER COLORADO
250 PM MDT SUN JUL 8 2001

MEAN POSITION OF UPPER LEVEL RIDGE TO BE OVER SOUTHEAST COLORADO
THROUGH TUESDAY...WHICH KEEPS CWA UNDER  MONSOON-TYPE MOISTURE
CIRCULATION.  WITH HIGH PRECIPITABLE WATER VALUES PROGGED...EXPECT
CONTINUATION OF MAINLY AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS FOR THE PERIOD WITH HEAVY RAINERS POSSIBLE.

FOR TONIGHT...STORMS CONTINUE ACROSS MOUNTAINS AND FOOTHILLS...WITH
SOME REPORTS OF HEAVY RAINS AND SMALL HAIL ALREADY RECEIVED.  SOME
CONCERN FOR BURN AREAS AND POSSIBLE EROSION.  RADAR SHOWING BOUNDARY
MEANDERING ALONG SOUTHERN WELD COUNTY.  ACROSS PLAINS...DECENT
DIRECTIONAL SHEAR AND CAPES AROUND 1500 JOULES TO SUPPORT STRONG TO
POSSIBLY SEVERE THUNDERSTORMS...MAINLY NORTH OF INTERSTATE 70.  SPC
HAS ALREADY ISSUED SVR TSTM WATCH FOR THIS AREA.  POTENTIAL FOR
HEAVY RAIN AND SOME FLOODING...ESPECIALLY SINCE GROUND NORTH OF
INTERSTATE 76 SATURATED.  HOWEVER...WILL NOT ISSUE A FLASH FLOOD
WATCH DUE TO THE SEVERE THUNDERSTORM WATCH ALREADY IN EFFECT.  COULD
BE A BIT OF CONFUSION.  AS IN PREVIOUS NIGHTS...STORMS SHOULD LAST
WELL INTO THE NIGHT...ESPECIALLY OVER NORTHEAST PLAINS.

ON MONDAY AND MONDAY NIGHT...ANOTHER ROUND OF MAINLY AFTERNOON AND
THUNDERSTORMS EXPECTED.  SOME STORMS TO PRODUCE HEAVY RAINS AS
PRECIPITABLE WATER VALUES PROGGED BETWEEN 1 INCH AND 1.5 INCHES
ACROSS THE PLAINS AND AROUND .75 INCHES FOR MOUNTAINS AND FOOTHILLS.
MODELS SHOW SHORTWAVE MOVING ACROSS CWA DURING AFTERNOON...WHICH
COULD ENHANCE RAINFALL.  STEERING WINDS PROGGED TO BE AROUND 10
KNOTS...SO STORMS SHOULD BE SLOW-MOVING AND COULD DUMP ALOT OF RAIN
IN A GIVEN SPOT.  MODELS ALSO SHOW WEAK SURGE DURING THE MORNING...
AND COOLER AIR COULD BREAK STRING OF CONSECUTIVE DAYS WITH 90
DEGREES AT DENVER.  STORMS EXPECTED TO LAST INTO THE NIGHT...AGAIN.

FOR TUESDAY AND TUESDAY NIGHT...STORMS SHOULD AGAIN FIRE LATE
MORNING ACROSS MOUNTAINS AND FOOTHILLS...GRADUALLY MOVING ACROSS THE
PLAINS DURING THE AFTERNOON.  DESPITE AN INCREASE IN STEERING
WINDS...SOME STORMS WILL AGAIN HAVE POTENTIAL FOR PRODUCING HEAVY
RAINFALL.  TEMPERATURE AND THICKNESS GRIDS SUPPORT TEMPERATURES IN
THE 80S.

FOR THE EXTENDED...SEE LITTLE CHANGE THROUGH THURSDAY AS LONG TERM
MODELS KEEP UPPER HIGH CENTERED NEAR THE TEXAS PANHANDLE...ALLOWING
FOR CONTINUED MOISTURE STREAM ACROSS CWA.  BEYOND THURSDAY...MRF
INDICATES HIGH SHIFTING WESTWARD...CENTERING OVER WESTERN NEW
MEXICO.  THIS SUGGESTS MOISTURE COULD BE SHUT OFF...INDICATING LESS
CHANCES FOR STORMS.  IN ANY CASE...WILL KEEP THE CHANCE OF STORMS
GOING.    D-L

.DEN...NONE.

COZ030>051-082000-

SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER COLORADO
1040 AM MDT SUN JUL 8 2001

THIS OUTLOOK PERTAINS TO THE FOLLOWING COLORADO COUNTIES

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

SYNOPSIS...AN UPPER LEVEL RIDGE OF HIGH PRESSURE ANCHORED OVER THE
CENTRAL GREAT PLAINS WILL CONTINUE TO ALLOW TROPICAL MONSOONAL
MOISTURE TO CIRCULATE NORTH FROM MEXICO ACROSS THE DESERT SOUTHWEST
AND GREAT BASIN INTO THE CENTRAL ROCKY MOUNTAINS.  A WEAK UPPER
LEVEL DISTURBANCE IN THIS WEST TO SOUTHWESTERLY FLOW ALOFT WILL
CONTRIBUTE TO THE OVERALL INSTABILITY OF THE AIR MASS AS WILL AMPLE
LOW LEVEL MOISTURE OVER THE HIGH PLAINS WHERE SURFACE DEWPOINTS WILL
REMAIN IN THE 50S AND LOWER 60S.  INCREASING LOW LEVEL EASTERLY
UPSLOPE FLOW THIS AFTERNOON AND EVENING OVER THE HIGH PLAINS WILL
ENHANCE THUNDERSTORM DEVELOPMENT ALONG THE EASTERN FOOTHILLS.
ADEQUATE DIRECTIONAL SHEAR WILL BE PRESENT FOR THE DEVELOPMENT OF
ISOLATED SEVERE THUNDERSTORMS OVER THE PLAINS EVEN THOUGH THE
OCCURRENCE OF LARGE HAIL MAY BE REDUCED BY FREEZING LEVELS WELL
ABOVE 16 THOUSAND FEET MSL.  AMPLE MOISTURE WILL BE PRESENT FOR
LOCALLY HEAVY THUNDERSTORM RAINS.  TRAINING OF STORMS ACROSS THE
SAME AREA WILL CAUSE INCREASED TOTAL RAINFALL.

SCATTERED SHOWERS AND THUNDERSTORMS WILL FORM OVER THE MOUNTAINS
AND EASTERN FOOTHILLS DURING THE EARLY AFTERNOON AND MOVE TO THE
EAST AND NORTHEAST OVER THE URBAN CORRIDOR AND HIGH PLAINS DURING
THE LATE AFTERNOON AND EVENING.  ISOLATED SEVERE THUNDERSTORMS WILL
PRODUCE LARGE HAIL...DAMAGING WINDS AND HEAVY RAIN WITH UP TO 2.50
INCHES OF RAINFALL IN AN HOUR.  THIS AMOUNT OF RAIN MAY CAUSE
FLOODING OF SMALL STREAMS...NORMALLY DRY GULCHES...FLOOD PRONE OR
LOW LYING AREAS...HIGHWAYS AND URBAN STREETS AND UNDERPASSES...BUT
WILL NOT BE SUFFICIENT FOR MAJOR STREAM OR RIVER FLOODING.

SPOTTER ACTIVATION MAY BE REQUIRED.

GARD...WFO BOULDER