Severe Thunderstorm Warning 71, NWS Denver/Boulder, CO

NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER COLORADO
230 PM MDT THU JUL 20 2000

STAGE IS SET FOR SVR WEATHER ON THE NERN PLAINS OF CO LATER THIS
AFTN AND EVE TIL 03Z.  SPC HAS ISSUED A TORNADO WATCH FOR NRLY ALL
OF NERN CO...EXCLUDING FOR SEDGWICK...PHILLIPS AND LOGAN COUNTIES IN
FAR NENR CORNER OF STATE WHERE MOISTURE AND INSTABILITY NOT AS
FAVORABLE.  HWVR...COULD SEE ISOLD SVR THIS EVE IN THESE CTYS WHERE
VERT SHEAR QUITE IMPRESSIVE AS PER ETA-WITH 0-3KM HELICITIES IN THE
200-215 RANGE.  FARTHER S...INCRSG LOW LVL MSTR...STG VERT SHEAR...
STEEP LAPSE RATES AND SFC/BNDRY LYR CAPES OFF THE ETA IN THE 3300-
4400 J/KG BTWN 21Z AND 03Z.  FOR INSTANCE...ETA IS GIVING 3855 J/KG
OF CAPE AT DEN AS OF 21Z AND AN IMPRESSIVE 4400 J/KG AT LIMON.
0-3KM HELICITIES WERE IN THE 45 TO 95 RANGE OFF ETA...WITH E-NELY
UPSLOPE FLOW DEEPENING WITH WLY SURGE OF BNDRY LYR AIR. ISOLD
TORNADOES...VRY LARGE HAIL AND DAMAGING STRAIGHT LINE WINDS APRS TO
BE MAIN THREAT.  HVY RAINFALL ALSO POSSIBLE BUT STORM MOTIONS
PROBABLY FAST ENOUGH TO CONFINE IT TO A FEW TSTM COMPLEXES.  SEE SVR
WX POTENTIAL FALLING OFF WITHIN THE URBAN CORRIDOR BY 02Z...BUT
LINGERING TIL PSBLY MIDNIGHT IN AREAS E/SE OF LIMON WHERE SVR THREAT
APRS GREATEST.  ONCE STORMS END...MOIST OUTFLOW AIR AND WK UPSLP
GRADIENT SHOULD CLOUD IN AREAS ALONG FNT RNG AND OVR THE MONUMENT
RIDGE AFT 06Z.  ALREADY HAVE CLOUDS AND AREAS OF FOG MENTIONED IN
FCST FOR TONIGHT.

ON FRIDAY...WARMUP WILL BE SLOW DURING THE MRNG WITH SCT LOW CLDS
AND PTCHY FOG AROUND.  ONCE SUN BREAKS OUT SHOULD SEE RAPID HEATING
AND DESTABILIZATION ON THE PLAINS WITH SBCAPES PROGD IN THE
1800-2700 J/KG RANGE BY 21Z.  ETA SOUNDINGS SHOW LAPSE RATES
STEEPENING DURING THE AFTN IN ADVANCE OF A MODERATELY STRONG 700-500
SHRTWV/THERMAL TROF DROPPING S/SEWRD OUT OF ERN WY.  WITH STG
COOLING ALOFT AND AMPLE LOW LVL MOISTURE ON THE NERN PLNS...COULD
SEE ANOTHER ROUND OF SVR WX LATE FRI AFTN AND EVE.  MAIN THREAT
LOOKS TO BE VRY LARGE HAIL.  NERN CORNER OF STATE APRS TO BE IN BEST
POSITION FOR SVR WEATHER.  LCLLY HVY RAINFALL ALSO PSBL WITH FNTL
STORMS.  INTENSITY/COVERAGE OF SVR WX WILL ALL DEPENDS ON TIMING OF
SHRTWV AND FRONT.  OTWS...MTN LOCALS SHOULD SEE LITTLE CHG IN TEMPS
AND WX NEXT 48 HRS WITH THE USUAL CHC OF AFTN AND ERLY EVE TSTORMS.

SATURDAY LOOKS TO BE A SLIGHTLY COOLER DAY FOR THE PLAINS WITH
POST-FRONTAL ELY FLOW IN PLACE.  LOW ATMOSPHERE WILL PROBABLY BE TOO
STABLE FOR ANYTHING MORE THAN A FEW LATE DAY TSTMS OVR AND NR THE
FTHLS AND MONUMENT RIDGE.

OUTLOOK FOR SUNDAY THROUGH TUESDAY...SEE LITTLE WARMING AND LOW CHC
FOR PCPN ON SUNDAY WITH A DRIER AMS AND COOL NWLY FLOW WITH UPR
RIDGE BUILDING OVR THE GREAT BASIN.  MONDAY AND TUESDAY...LOW LVL
MOISTURE SLOWLY FILTERS IN FM THE W/SW WITH UPR RIDGE FLATTENING.
WILL GO WITH WARMER TEMPS AND THROW IN A CHANCE AFTN/EVE T-STORMS
EACH DAY.  BAKER

.DEN...TORNADO WATCH UNTIL 03Z THIS EVE FOR NEARLY ALL OF NERN CO
       ZNS 38>47 AND 49.

COZ030-032>050-202000-

SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER CO
1000 AM MDT THU JULY 20 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:  SURFACE HIGH PRESSURE WILL BUILD INTO THE CENTRAL PLAINS
THROUGH THIS AFTERNOON...ALLOWING FOR MOIST EASTERLY UPSLOPE WINDS
TO DEVELOP ACROSS THE NORTHEAST PLAINS OF COLORADO.  INCREASING LOW
LEVEL MOISTURE COUPLED WITH AFTERNOON HEATING WILL LEAD TO THE
FORMATION OF SCATTERED THUNDERSTORMS...ALONG AND EAST OF THE FRONT
RANGE FOOTHILLS...AFTER 4 PM.

A FAVORABLE SHEAR PROFILE SHOULD BE SUFFICIENT FOR THE FORMATION OF
THE FEW SEVERE THUNDERSTORMS...ESPECIALLY ALONG AND EAST OF THE
INTERSTATE 25 CORRIDOR.  LARGE HAIL AND DAMAGING WINDS WILL BE THE
MAIN THREATS.  AN ISOLATED TORNADO HOWEVER CANNOT BE RULED OUT NEAR
ANY BOUNDARY INTERACTIONS.

SPOTTER ACTIVATION MAY BE NEEDED LATE THIS AFTERNOON AND EVENING
OVER PORTIONS OF NORTHEAST COLORADO.

IN THE FOOTHILLS...SOME OF THE STORMS COULD PRODUCE LOCALLY HEAVY
RAIN WHICH COULD POSE A FLASH FLOOD THREAT TO THE HI MEADOWS AND
BOBCAT BURN AREAS.  THERE IS STILL A QUESTION HOWEVER AS TO HOW DEEP
THE UPSLOPE ADVERTISED IN THE MODELS WILL GET.  SHOULD STRONG
THUNDERSTORMS DEVELOP...RAINFALL REPORTS FROM ANY SPOTTERS IN OR
NEAR THESE BURN AREAS WOULD BE GREATLY APPRECIATED.

COOPER

COZ030-032>050-202200-

SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER CO
1 PM MDT THU JULY 20 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:  EASTERLY WINDS IN THE LOWER LEVEL OF THE ATMOSPHERE
CONTINUE TO PUMP MOISTURE INTO THE NORTHEASTERN PLAINS OF COLORADO.
THIS MOISTURE COUPLED WITH AFTERNOON HEATING WILL BE SUFFICIENT
ENOUGH FOR THE FORMATION OF THUNDERSTORMS.  AT 1 PM...THUNDERSTORMS
WERE ALREADY DEVELOPING ALONG THE FOOTHILLS OF JEFFERSON...NORTHEAST
PARK AND DOUGLAS COUNTIES.

A FAVORABLE SHEAR PROFILE IN THE ATMOSPHERE APPEARS TO BE SUFFICIENT
ENOUGH FOR THE FORMATION OF THE FEW SEVERE THUNDERSTORMS...
ESPECIALLY ALONG AND EAST OF THE INTERSTATE 25 CORRIDOR.  LARGE HAIL
AND DAMAGING WINDS WILL BE THE MAIN THREATS.  AN ISOLATED TORNADO
HOWEVER CANNOT BE RULED OUT NEAR ANY BOUNDARY INTERACTIONS.

SPOTTER ACTIVATION WILL BE NECESSARY FOR AREAS ALONG AND EAST OF THE
AFORMENTIONED AREA AFTER 2 PM.

IN THE FOOTHILLS...SOME OF THE STORMS COULD PRODUCE LOCALLY HEAVY
RAIN WHICH COULD POSE A FLASH FLOOD THREAT TO THE HI MEADOWS AND
BOBCAT BURN AREAS.  RAI<NFALL REPORTS FROM SPOTTERS IN AND NEAR THE
BURN AREAS WOULD BE GREATLY APPRECIATED.

COOPER