Flash Flooding in Colorado, July 4, 2002

NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER COLORADO
235 PM MDT THU JUL 04 2002

SHORT TERM DISCUSSION:  CONVECTION CONTINUES TO FIRE ACROSS
MOUNTAINS AND FOOTHILLS AS MOIST SOUTHEASTERLY WINDS PERSIST OVER
THE PLAINS.  WEAK FLOW ALOFT EQUATES TO SLOW MOVING STORMS...WITH
MOTION TO THE NORTH NORTHWEST.  PATTERN SIMILAR TO YESTERDAY...AND
MAIN THREAT WILL BE HEAVY RAIN AND LOCALIZED FLOODING DUE TO SLOW
MOVEMENT.  DESPITE WEAK WIND SHEAR...THE POTENTIAL FOR HAIL AND
MICROBURST WINDS CANNOT BE RULED OUT.  ACROSS THE PLAINS...AIRMASS
SEEMS STABLE FOR CONVECTION.  HOWEVER...RADAR SHOWS A FEW BOUNDARIES
WHICH COULD BECOME THE FOCUS FOR DEVELOPMENT.  ALL ACTIVITY SHOULD
END THIS EVENING AS MODELS SHOW LITTLE IN THE WAY OF ANY FORCING TO
PROLONG ACTIVITY.

ON FRIDAY...FEATURES CHANGE LITTLE AS WEAKENING UPPER LOW SLIDES
ACROSS NEW MEXICO.   MODELS CONTINUE TO INDICATE GULF MOISTURE TO BE
SHUNTED EAST...BUT STILL INDICATE PRECIPITABLE WATER VALUES AROUND
EIGHT TENTHS OF AN INCH.  LATEST SATELLITE AND LIGHTNING CHARTS SHOW
FAIRLY ACTIVE SHORTWAVE OVER TEXAS WHICH WHICH THE MODELS SHOW
MOVING ACROSS CWA DURING AFTERNOON.  SCATTERED POPS ACROSS MUCH OF
CWA STILL ON TRACK.  SHORTWAVE SHOULD BE OUT OF AREA BY EVENING...
THOUGH MODELS KEEP WAVE OVER AREA THROUGH SATURDAY AM.  WILL END
STORMS DURING EVENING...BUT COULD END UP BEING A LATE SHOW.

FOR SATURDAY...MODELS STILL ADVERTISE WEAK SURFACE FRONT MOVING INTO
THE EASTERN PLAINS IN THE MORNING...WITH NORTHEASTERLY UPSLOPE FLOW
AND COOLER TEMPERATURES IN PLACE.  MODELS INDICATE ENOUGH OF A CAP
OVER THE PLAINS WHICH COULD LIMIT CONVECTION DESPITE THE HIGH
PRECIPITABLE WATER VALUES.  DIV-Q PROGS SHOW SOME WEAK ASCENT DURING
THE DAY...PROBABLY DUE TO REMNANTS OF UPPER LOW.  CURRENT POPS OF
ISOLATED FOR PLAINS MAY BE A BIT LOW...WILL LEAVE AS IS FOR NOW.
SCATTERED POPS GOOD ELSEWHERE.  CONVECTION NOT EXPECTED TO PERSIST
OVERNIGHT.  WITH THE COOLER TEMPERATURES IN PLACE...THE STRING OF 90
DEGREES F. SHOULD END.

ON SUNDAY...AIRMASS BEGINS TO MODIFY SLIGHTLY AS UPPER LEVEL RIDGE
BEGINS TO BUILD OVER GREAT BASIN.  ABUNDANT MOISTURE TO REMAIN IN
PLACE FOR A CONTINUED CHANCE FOR AFTERNOON STORMS.  CROSS SECTIONS
AND FORECAST SOUNDINGS SHOW SOME DIRECTIONAL SHEAR...BUT DOESNT
SEEM IMPRESSIVE ENOUGH FOR SEVERE.

LONG TERM DISCUSSION: MONDAY THROUGH THURSDAY...STRONG UPPER HIGH
WILL PARK ITSELF OVER  THE NRN GREAT BASIN WHICH KEEPS AREA IN
NORTHERLY FLOW.  THIS WILL HELP TO SHUNT BULK OF MOISTURE AWAY FROM
AREA.  HOWEVER...CANNOT RULE OUT THE DAILY CHANCE OF AFTERNOON AND
EVENING STORMS.  TEMPERATURES WILL BE AT OR NEAR NORMAL READINGS.
D-L

.DEN...NONE