Severe Thunderstorm Warning 129, NWS Denver/Boulder, CO

NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER COLORADO
220 PM MDT FRI SEP 8 2000

CLOUDS CONT TO OVER SPREAD THE CWA FM THE SW THIS AFTN IN ADVANCE OF
MDTLY STG SRN STREAM VORT MAX/SHRTWV EJECTING NEWRD ACRS SWRN UT
ATTM.  ETA AND NGM PRETTY MUCH PEGGED 18Z POSITION OF 5H VORT CENTER
VSBL ON SATL IMAGERY...WHILE AVN SOLUTION SHOWED 5H VORT MAX STILL
OVR SRN NV NR LAS VEGAS AT THAT TIME.  BOTH ETA AND NGM TRACK 5H
VORT CENTER EWRD ACRS SRN UT BEFORE STEERING NEWRD ACRS NERN CO BTWN
06Z-12Z/SAT.  ETA TAKES OVR AS THE FASTER MDL DURING THIS PD AS IT
SHOWS A TIGHT 5H VORT CENTER OVR DEN AT 06Z/SAT.  SOME QUESTION AS
TO HOW MUCH MOISTURE WILL MAKE IT OVR THE MTNS WITH THIS SYSTEM.
T-STORMS DOTTING ERN UT/WRN CO IN A RGN OF STEEP LAPSE RATES AND
7-5H VERT VELOCITIES ON LEFT FNT QUAD OF +80KT JET MAXIMA PASSING
OVR SERN UT.  WITH REGARD TO PRECIP POPS 1ST PD...ETA SHOWS JET CORE
WITH UNDERLYING SUBSIDING AIR PASSING OVR THE SRN FNT RNG URBAN
CORRIDOR AND NERN PLAINS DURING THE EVE HRS. WHEREAS...NRN MTNS AND
NRN FNT RNG URBAN CORRIDOR WILL PSBLY COME FAVORABLE SYNOPTIC LIFT
AND INSTABILITY FOR A BETTER CHC FOR LATE AFTN AND EVE SHWRS AND
T-STORMS.  HWVR WOULD NOT RULE OUT STORMS FIRING ALONG WND GUST FNTS
ROLLING OFF SRN FTHLS...ACRS DEN METRO AREA AND ONTO ADJACENT PLNS.
ONE OR TWO STORMS MAY APRCH SVR UNDER JET SHEAR RGN GENERALLY N OF A
LN FM DEN TO STERLING.  FAVORABLE VERT SHEAR PROFILE AND COOLING
ALOFT COULD SUPPORT ISOLD LARGE HAIL AND A BRIEF SPIN UP/ GUSTNADO
LATER THIS AFTN AND ERLY THIS EVE.  OTWS...SHOULD SEE SKIES CLRG AFT
MIDNIGHT FM SW TO NE WITH STG W-NWLY WNDS DVLPG IN THE MTNS AND HIR
FTHLS FOLLOWING PASSAGE OF MID-LVL SHRTWV AND STAND-UP PAC COLD
FNT.  COULD SEE A FEW HRS OF STG DOWNSLOPE (BORA-TYPE) WNDS AT BASE
OF FTHLS ARND DAWN AS WELL.

ON SAT...STG ZONAL FLOW AT THE BASE OF BROAD UPR LVL TROF PASSING
OVR NRN TIER WITH KP GUSTY W-NWLY WINDS BLOWING IN THE MTNS AND
FTHLS FOR MOST OF THE DAY.  AS MID-LVL SUBSIDENCE WEAKENS...SHOULD
SEE WINDS SUBSIDING BEFORE DARK.  DUE TO LACK OF MOISTURE AND
DOWNSLOPE PRES GRADIENT...THE CHANCE FOR PRECIP LOOKS QUITE LOW
SAT...WITH ONLY ISOLD AFTN SHWRS/T-SHWRS IN THE MTNS.

DURING THE EXTENDED PD...SUN LOOKS TO BE A BIT WARMER AND EVEN DRIER
WITH CONTINUATION OF WK WLY FLOW AND NEUTRAL MID-LVL LAPSE RATES.
ON SUN AVN SHOWS A VIGOROUS MID-LVL SHRTWV DIVING SEWRD WITH COLD
AIR ACRS THE PAC NW AND OVR WY BY MIDDAY MON.  MDL ALSO SHOWS A
DISTURBANCE PASSING OVR CO AT THE SAME TIME...BUT MOISTURE THIS FAR
SOUTH APPEARS LIMITED.  TUE AND WED ALSO LOOK DRY WITH LITTLE CHG IN
TEMPS.  CURRENT FCST ALREADY REFLECTS THIS...SO NO CHANGES HERE.
BAKER

.DEN...NONE

COZ030-032>050-082030-

SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER CO
143 PM MDT FRI SEP 8 2000

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 DISTURBANCE WILL MOVE ACROSS THE AREA BY
TONIGHT.  THIS SYSTEM COMBINED WITH SOME SUBTROPICAL MOISTURE WILL
HELP TRIGGER WIDELY SCATTERED THUNDERSTORMS OVER THE REGION THROUGH
THIS EVENING.  THE STORMS WILL PRODUCE GUSTY WINDS TO 50 MPH AND
QUITE A BIT OF LIGHTNING HOWEVER RAINFALL AMOUNTS WILL BE GENERALLY
ON THE LIGHT SIDE.

SPOTTER ACTIVATION WILL NOT BE NEEDED THIS AFTERNOON OR TONIGHT.

RPK