Severe Thunderstorm Warning 150, NWS Denver/Boulder, CO

NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER COLORADO
234 PM MDT FRI SEP 14 2001

UPPER TROUGH OF LOW PRESSURE CURRENTLY OVER EASTERN MONTANA DOESNT
PLAN ON MOVING MUCH THROUGH THE NEXT 48 HRS ACCORDING TO THE ETA.
WITH COMPLEX PATTERN OVER MUCH OF THE USA...CANT REALLY ARGUE
AGAINST MODELS SOLUTIONS FOR THE FUTURE ATTM.  FIRST ITEM TO BE
CONCERNED WITH TODAY IS BETTER MOISTURE OVER THE EASTERN PLAINS DUE
TO LAST NIGHTS COOL SURGE AND AN ADVANCING JET MAX WHICH IS EXPECTED
TO RUN OVER COLO/WYO BORDER TONIGHT THROUGH SAT.  THIS COULD MAKE
FOR AN ACTIVE EVENING ON THE NORTHERN PLAINS AND WILL BUMP POPS UP A
CATEGORY FOR THIS.  SECOND ITEM IS THE COLD FRONT WHICH IS CURRENTLY
ADVANCING SOUTH ACROSS WYO AND IS LIKELY TO ARRIVE IN THE BOU CWA IN
THE 03Z-06Z SAT TIME FRAME.  CURRENT FCST LOOKS ON TRACK WITH
MENTION OF SEVERE ON THE FAR PLAINS TONIGHT AND SCATTERED COVERAGE
OVER MUCH OF CWA FOR SAT AND SAT NIGHT.  WILL EXPECT A MUCH COOLER
DAY ON THE PLAINS...URBAN CORRIDOR AND FOOTHILLS WITH LOW CLOUDS...
LIGHT EARLY DAY PRECIP AND AFTERNOON THUNDERSTORMS AND A 10 TO 15
DEGF COOL DOWN.  DECENT DIV-Q ASCENT BECOMES PRESENT OVER NORTHERN
COLORADO LATE TONIGHT WITH SUBSIDENCE TAKING OVER BY 18Z SAT.  WILL
NOT EXPECT TOO MUCH IN THE WAY OF POPS IN THE HIGH COUNTRY SAT AND
SAT EVE DUE TO RELATIVE SHALLOWNESS OF MOISTURE AND QUICK TRANSFER
OVER TO A SUBSIDENT ENVIRONMENT WITH THE TROUGH AXIS PASSAGE A DRYER
AIRMASS FROM THE WEST AND WESTERLY SFC FLOW. GUIDANCE TEMPS ARE ALL
OVER THE PLACE FOR SATURDAY AND ITS PROBABLE THAT HIGHS WILL NOT GET
OUT OF THE 60S AT MOST LOCATIONS EVEN WITH CLOUDS DECREASING IN THE
AFTERNOON.  FCST SOUNDINGS OVER THE AREA SHOW ENTIRE SOUNDING
TRENDING TO A WESTERLY DIRECT BY MIDDAY SUNDAY WITH DRYING AT THE
LOW LEVELS.

EXTENDED PD...MONDAY THROUGH FRIDAY...AVN SHOWS UPPER LOW FINALLY
LEAVING THE DAKOTAS AREA LATE MONDAY INTO TUESDAY.  IN DOING SO...
AVN SFC FIELDS BRING ANOTHER SURGE INTO THE NORTHEAST PLAINS FOR
TUESDAY INTO WEDNESDAY AS NORTHERLY FLOW BEHING TROUGH PUSHES COOL
AIR SOUTH.  THERE IS WEAK SHORT WAVE EMBEDDED IN THE INCREASING
NORTHWESTERLY FLOW WITH SOME MORE DIV-Q ASCENT AND WILL KEEP CHANCE
FOR PRECIP FOR TUESDAY AND WEDNESDAY.  FLOW ALOFT REMAINS
NORTHWESTERLY FOR THURSDAY AND FRIDAY BUT DRYING TAKES PLACE OVER
THE WESTERN USA WITH BUILDING RIDGE.   FREDIN

.DEN...NONE.

COZ030>051-142000-

HAZARDOUS WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER CO
1050 AM MDT FRI SEP 14 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...WHILE DRIER AIR FROM THE WEST HAS SPREAD OVER THE CENTRAL
ROCKY MOUNTAINS TODAY...THE AIR MASS WILL STILL REMAIN RELATIVELY
MOIST AND UNSTABLE ACROSS THE FORECAST AREA.  AN UPPER LEVEL
DISTURBANCE ASSOCIATED WITH A JET STREAM ORIENTED FROM WEST TO EAST
ALONG THE WYOMING AND COLORADO BORDER WILL ENHANCE VERTICAL LIFT.
THE AIR MASS WILL BE MOST UNSTABLE OVER THE NORTHEASTERN CORNER
OF THE STATE...WHERE ISOLATED THUNDERSTORMS MAY BECOME SEVERE
LATER THIS AFTERNOON AND EVENING.

SCATTERED SHOWERS AND THUNDERSTORMS WILL FORM OVER THE MOUNTAINS
AND EASTERN FOOTHILLS BY EARLY AFTERNOON AND SPREAD EAST OVER THE
PLAINS THROUGH THE EVENING HOURS.  ISOLATED SEVERE THUNDERSTORMS
ARE POSSIBLE OVER THE NORTHEAST CORNER OF COLORADO.  THESE STORMS
MAY PRODUCE LARGE HAIL...DAMAGING WINDS AND HEAVY RAIN.

SPOTTER ACTIVATION WILL NOT BE REQUIRED.

ON SATURDAY...THE AIR MASS AT LOW LEVELS WILL BE MORE MOIST BUT
COOLER OVER THE PLAINS BEHIND A COLD FRONT.  WITH A MORE STABLE
ATMOSPHERE ONLY ISOLATED LATE DAY THUNDERSTORMS ARE EXPECTED.

GARD...WFO BOULDER