Severe Thunderstorm Warning 2, NWS Denver/Boulder, CO

NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER COLORADO
225 PM MDT SAT JUN 01 2002

SHORT TERM DISCUSSION:  RADAR AND SFC ANALYSIS SHOW SOME TYPE OF SFC
LOW OVR ERN ADAMS AND ARAPAHOE COUNTIES WITH SOME TYPE OF WK BNDRY
EXTENDING FM GXY TO NR AKO INTO SWRN NE.  SFC BASED CAPES HAVE RISEN
TO AROUND 2000 J/KG OVR THE NERN CO MAINLY EAST OF A STERLING TO AKO
LN.  HI BASED STORMS HAVE BEEN DVLPG NR INTERSECTION OF SFC
LOW...DRYLINE AND WK FNTL BNDRY.  AS THESE STORMS MOVE INTO MORE
UNSTABLE AIR OVR NERN CORNER COULD SEE A FEW SVR STORMS WITH LARGE
HAIL AND STG WNDS.  MEANWHILE MID AND HI LVL MSTR IS INCRG IN
ADVANCE OF DISTRURBANCE MOVING ACRS UTAH THIS AFTN.  THIS IS LEADING
TO ADDITIONAL HI BASED SHRA AND TSRA DEVELOPMENT IN THE MTNS WHICH
WL LINGER INTO THE EVENING HRS.

FOR SUN APPEARS TO BE ANOTHER HOT AND DRY DAY OVR NRN CO WITH
ANOTHER RECORD HIGH IN DENVER PSBL AS 700 MB TEMPS REMAIN AOA 15
DEGREES C.  MSTR WL BE VERY LIMITED SO DONT THINK THERE WL BE MUCH
ACTIVITY IN THE MTNS OR NERN CO.  MESO-ETA IS SHOWING SOME TYPE OF
BNDRY OVR THE NERN CORNER INITIALLY APPARENTLY IN RESPONSE TO MCS
DEVELOPMENT OVR NEBRASKA TONIGHT.  HOWEVER THIS FEATURE IS FCST TO
GRADUALLY WASH OUT BY AFTN BUT IF IT DOES MAINTAIN ITSELF ENOUGH LOW
LVL MSTR MY EXIST FOR A FEW LATE AFTN AND EVENING STORMS.

LONGER TERM DISCUSSION:  MAIN CHALLENGE FOR MON AND TUE WL BE HOW
UPR LVL TROF DVLPS OVR RGN.  THERE IS SOME MAJOR DISAGREEMENT
BETWEEN THE MODELS ON HOW TO HANDLE THIS SYSTEM.  ETA...NGM...NOGAPS
AND EUROPEAN ALL SHOW AN UPR LVL LOW DVLPG OVR SWRN US BY MON WHILE
AVN KEEPS SYSTEM PROGRESSIVE AND RATHER DISORGANIZED WITH BRUNT OF
UPR LVL TROF MOVING ACRS CNTRL AND NRN ROCKIES.  WITH 4 OUT OF 5
MODELS SHOWING MORE ENERGY IN SRN BRANCH OF TROF WL TREND FCST
TOWARDS ETA...NGM...NOGAPS AND EUROPEAN SOLUTIONS.  MEANWHILE A
FAIRLY STG CDFNT WL MOVE INTO NERN CO BY 12Z MON AND BRING MUCH
COOLER TEMPS ALONG WITHG INCRG UPSLOPE FLOW AND LOW LVL MSTR.  IF
LOW CLOUDS BURN OFF BY MIDDAY APPEARS ENOUGH WARMING WL TAKE PLACE
TO ALLOW FOR TSTMS TO DVLP NR THE FOOTHILLS BY MID TO LATE AFTN.
GRIDDED FIELDS ALSO SHOW SOME MINOR MID-LVL QG ASCENT AND FAVORABLE
UPR LVL DIVERGENCE TO ENHANCE PCPN CHCS AS WELL.  SOUNDINGS SHOW SFC
BASED CAPES COULD REACH AROUND 2000 J/KG BY MON AFTN IF TEMPS CAN
WRM INTO THE LOWER TO MID 70S WITH GOOD TURNING IN THE LOWER LEVELS
AS STRM RELATIVE HELICITIES ARE FCST AROUND 150 M2/S2.  THUS COULD
SEE 1ST SIGNIFICANT SVR WX OUTBREAK OF THE SEASON OVR NERN CO IF
ENOUGH WARMING OCCURS AT THE SFC.  700 MB TEMPS ARE FCST TO COOL
ABOUT 8-10 DEGREES C SO TEMPS WL BE AT LEAST 20 DEGREES COOLER OVR
NERN CO INTO THE FOOTHILLS.

BY MON NGT AND TUE LATEST UPSLOPE FLOW WL CONT AS SFC HI PRES BUILDS
S INTO NRN CO.  THIS COULD LEAD TO MORE OF A GENERAL RAIN EVENT MON
NGT INTO TUE DEPENDING ON HOW UPR LVL TROF DVLPS AS ETA EXTENSION
THRU 84 HRS SHOWS QUITE A BIT OF PCPN ACRS NRN CO. FOR NOW WL JUST
GO WITH CHC POPS MON NGT INTO TUE SINCE STILL NOT SURE WHICH MODEL
WL BE CORRECT.  700 MB TEMPS ARE FCST TO DROP TO ROUND 0 DEGREES C
ON TUE ACCORDING TO LATEST AVN WHICH WOULD KEEP TEMPS IN THE 50S
ACRS NERN CO FOR AFTN HIGHS.  COULD SEE SOME RAIN MIX WITH SNOW IN
THE HIGHER MTNS AND FOOTHILLS MAINLY ABV 9,000 FT.

BY WED IF I BELIEVE THE NOGAPS AND EUROPEAN SOLUTIONS UPR LVL LOW WL
RETROGRADE SW TOWARDS BAJA AS SFC HI BUILDS ACRS CO ALLOWING FOR
BEST MSTR TO SAG SOUTH OF AREA.  700 MB TEMPS ARE ONLY FCST ARE +2
OR +3 BY WED AFTN WHICH COULD KEEP HIGHS IN THE 60S ACRS NERN CO.

FOR THU THRU SAT LAST NIGHTS AVN SHOWED FLOW ALOFT BECOMING MORE
ZONAL WITH A GENERAL WARMING TREND.  SINCE WE ARE NOW IN THE MONTH
OF JUNE PROBABLY WL START SEEING SOME WDLY SCT AFTN AND EVENING
CONVECTION AS IT DOESNT TAKE MUCH MSTR TO GET THINGS GOING SO WL
INTRODUCE A SLIGHT CHC OF STORMS FOR SAT AND SUN.

KLEYLA

.DEN...NONE