Severe Thunderstorm Warning 154, NWS Denver/Boulder, CO

NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER COLORADO
255 PM MDT SAT SEP 15 2001

UPPER LOW CONTINUES TO SLOWLY SPIN OVER WESTERN SOUTH DAKOTA TODAY
WITH ZONAL FLOW EXPECTED TO DEVELOP OVER THE ROCKIES INTO SUNDAY.
ETA HAS THE CENTER OF THE LOW ONLY PROGESSING ABOUT 200 MILES IN 24
HRS BEFORE BREAKING APART INTO THE FLOW OVER MINN LATE MONDAY.  ALL
MODELS STILL SHOWING A SUBSIDENT ENVIRONMENT OVR NORTHERN COLO FOR
TONIGHT THROUGH SUNDAY.  RELUCTANT TO REMOVE ALL POPS FOR THE AREA
TONIGHT AND SUNDAY AS DECENT SURFACE MOISTURE FOR THIS TIME OF YEAR
STAYS AROUND COMBINED WITH GENERAL EASTERLY FLOW EXPECTED.  RIGHT
ENTRANCE REGION OF JET MAX SLOW TO LEAVE AREA ALSO.  AS UPPER TROUGH
LEAVES THE NORTHERN GREAT PLAINS OF THE USA...MODELS PERSISTANT TO
SHOW NORTHEASTERLY UPSLOPE SFC FLOW IN ITS WAKE FOR NORTHEAST COLO.
THIS IS IN THE FORM OF ANOTHER COOL SURGE THAT ENTERS THE BOU CWA
LATE SUNDAY INTO EARLY MONDAY AND HOLDS TEMPS DOWN FOR ANOTHER DAY.
MESO-ETA SHOWS ANOTHER ROUND OF HIGHER RH VALUES AND LIGHT PRECIP BY
MONDAY AFTERNOON BUT MAINLY NEAR HIGHER TERRAIN.  AVN BRINGS AREA OF
DIV-Q ASCENT ENTERING THE NORTH HALF OF THE STATE AHEAD OF WEAK
SHORT WAVE MONDAY INTO EARLY TUESDAY.  WILL NOT EXPECT AN ENTIRELY
CLOUDY AND RAINY DAY ON MONDAY BUT WILL BUMP POPS UP AGAIN FOR THE
AFTERNOON AND EVENING HOURS.  FOR TUESDAY...AVN HAS THE SHORT WAVE
TROUGH AXIS OVER THE DISTRICT BY 18Z TUE WITH DRYER WESTERLY SFC
FLOW BEHIND IT.  WEAK RIDGING TAKES PLACE HEADING INTO MID WEEK.

AT THIS TIME...LOOKS LIKE MILD SEPTEMBER WEATHER CAN BE EXPECTED FOR
WEDNESDAY THROUGH SATURDAY.  MODERATE NORTHWESTERLY FLOW ALOFT ON
WEDNESDAY TRENDS TO WEAK FLOW WITH A RIDGE AXIS IN THE VICINITY OF
THE STATE BY SAT MORNING ACCRODING TO THE MRF.  THE BEST CHANCE FOR
PRECIP IN THE FAR PERIODS WOULD BE ON THURSDAY AS MRF HAS A VERY
WEAK TROUGH ROUNDING THE RIDGE AND PASSING ACROSS THE NORTH HALF OF
THE STATE LATE IN THE DAY.  WILL NOT MENTION ANY CHANCE FOR PRECIP
FOR THIS YET DUE TO DISTANCE IN TIME AND LACK OF DETAIL.   FREDIN

.DEN...NONE.

COZ030>051-152000-

HAZARDOUS WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER CO
1100 AM MDT SAT SEP 15 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...SURFACE MOISTURE ON THE PLAINS INCREASED OVERNIGHT
ON LOW LEVEL UPSLOPE FLOW AGAINST THE EAST FACE OF THE ROCKY
MOUNTAINS.  THIS COUPLED WITH JET STREAM INDUCED INSTABILITY
IN THE MID AND UPPER ATMOSPHERE DURING THIS AFTERNOON AND EVENING
WILL ALLOW MORE SHOWERS AND THUNDERSTORMS TO DEVELOP OVER THE AREA
ONCE SUFFICIENT SURFACE HEATING OCCURS.

SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE TO FORM OVER THE
MOUNTAINS AND EASTERN FOOTHILLS.  THESE STORMS WILL GAIN STRENGTH AS
THEY SPREAD TO THE EAST OVER THE PLAINS THROUGH THIS EVENING.
ISOLATED SUPERCELL SEVERE THUNDERSTORMS ARE POSSIBLE OVER THE URBAN
CORRIDOR...THE PALMER DIVIDE AND THE EASTERN PLAINS THIS AFTERNOON
AND EVENING.  THESE STORMS MAY PRODUCE LARGE HAIL...DAMAGING WINDS
AND HEAVY RAIN.

SPOTTER ACTIVATION MAY BE REQUIRED THIS AFTERNOON.

ON SUNDAY...ONLY ISOLATED LATE DAY THUNDERSTORMS ARE EXPECTED.

GARD...WFO BOULDER