Hail and Damaging Wind in Colorado, May 30 to 31, 2001

SOUTH CENTRAL AND SOUTHEAST COLORADO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PUEBLO COLORADO
311 AM MDT WED MAY 30 2001

CURRENTLY: RGNL RADAR SHOWING BAND OF SHRA/TSTM ACROSS NERN CO IN
RESPONSE TO WEAK MID-LEVEL SHORTWAVE TROUGH...PER 40KM RUC 500-
300MB LAYER VORT.  PRECIPITATION HAVING A TOUGH TIME MOVING SWD AND
APPEARS TO BE WEAKENING/SHRINKING ON THE LAST FEW IMAGES.  LATEST
WATER VAPOR IMAGERY/RUC MODEL SHOWING NEXT FAST MOVING SHORTWAVE
ACROSS NRN GREAT BASIN AND SHOULD BE ENTERING NWRN CO LATER THIS AM.
ALSO...STRONG CYCLONE WAS LOCATED ACROSS ALBERTA CAN AND MAY
INFLUENCE ERN CWFA WEATHER BY FRI.

TDA-TNGT: THE THREAT FOR SEVERE WX SHOULD BE VERY LOW OR NIL TDA.
SHORT RANGE MODELS HAVING EXCELLENT AGREEMENT ON NEXT DISTURBANCE
FORECAST TO MOVE THROUGH CO THIS AFTN.  MID-LEVEL SHORTWAVE AND
ASSOCIATED 300-200MB PV ANOMALY PROGGED TO RACE ACROSS CWFA THIS
AFTN/EARLY EVE.  LOW LEVEL(850-700MB) FLOW SHOULD BECOME NE-ELY LATER
THIS AM/AFTN PROVIDING WEAK OROGRAPHIC ASCENT FOR SERN CO MTNS/
ADJACENT PLAINS AS SFC HIGH BUILDS IN SD.  SUFFICIENT VERTICAL
MOISTURE...700-500MB SPECIFIC HUMDITY VALUES 3-4 G/KG...STILL IN
PLACE FOR SHRA/TSTM PRODUCTION.  THIS COMBINED WITH LIFTING
MECHANISMS SHOULD BE ENOUGH TO WARRANT CURRENT LOW POPS IN ZFP.
INSTABILITY WILL NOT BE AS INTENSE AS IN THE PAST COUPLE OF DAYS.
CAPES PROGGED TO BE 200-1000 J/KG BY 18Z/30...THEN DECREASE DURING
THE AFTN.  BLAYER BEST LIS FORECAST TO BE 0C TO -2C. STEEPEST MID-
LEVEL LAPSE RATES...AROUND 9.0 C/KM...FORECAST TO BE IN WRN 1/2 OF
CO.  SO...SEVERE WX THREAT APPEARS TO BE VERY LOW...AT THE MOMENT. IF
STRONGER TSTMS DO FORM THIS AFTN...THEY MAY BE CAPABLE OF HAIL UP TO
1/2 INCH...WIND GUSTS UP TO 40 MPH...AND SEVERAL CLOUD TO GROUND
LIGHTNING STRIKES.  ALWAYS CONCERNED ABOUT LOW LEVEL ELY FLOW
JUXTAPOSED WITH W-NWLY FLOW NEAR THE SERN CO MTNS FOR THE POTENTIAL
OF SUPERCELLS.  0-6KM SHEAR PROGGED TO BE 30-35KTS ALONG SERN CO MTNS
THIS AFTN ALONG WITH 0-3KM HELICITY VALUES OF 150-200 M2/S2...BUT
CAPE FAIRLY WEAK AT BEST AND WOULDN'T SUPPORT VIGOROUS VERTICAL
VELOCITIES.  MAV/FWC MOS TEMP GUIDANCE COMING TOGETHER A LITTLE
BETTER FOR TDA'S HIGHS.  SHOULD BE ABLE TO REACH NEAR THESE NUMBERS
GIVEN A LITTLE SUNSHINE...BUT NE-ELY FLOW HAS A TENDENCY TO REALLY
TRIM TEMPS...CLOUD COVER WILL BE THE KEY. PRECIPITATION THREAT SHOULD
DIMINISH THIS EVE.  OVERALL...CURRENT ZFP LOOKS GOOD.

THU-THU NGT: 90-110KT ULJ FORECAST TO DIVE INTO NRN ROCKIES/NRN
PLAINS THU AFTN AS ASSOCIATED CYCLONE DROPS INTO UPPER MS RIVER
VALLEY THU NGT.  STRONG RIDING DEVELOPS IN WRN US BETWEEN CNTL US
SYSTEM AND INCOMING PACIFIC NW SYSTEM.  SFC FEATURES FAIRLY BENIGN.
HINTS OF WEAK SHORTWAVE MOVING THROUGH NWLY FLOW...BUT NO 300-200MB
PV ANOMALY ASSOCIATED WITH IT.  VERTICAL MOISTURE STILL HANGING
AROUND WITH 700MB TEMPS WARMING SLIGHTLY.  INSTABILITY AGAIN PRETTY
WEAK WITH CAPE VALUES 200-400 J/KG AND BLAYER BEST LIS 0C TO -2C.
ALL ELEMENTS IN PLACE FOR CURRENT LOW CONDITIONAL POP...MAINLY
DIURNAL SHRA/TSTM.  HINTS OF SOME WEAK 700MB WAA ACROSS SERN CO THU
NGT...WHICH COULD HELP INITIATE NON-SFC BASED SHRA/TSTM. WILL HOLD
OFF ON ADDING POPS TO SERN CO PLAINS THU NGT.  OTHERWISE...CURRENT
ZFP STILL LOOKS GOOD AND GENERALLY IN-LINE WITH NWP MOS GUIDANCE.
SEE NO REASON TO ALTER.

EXTENDED(FRI-TUE): THERE IS A LITTLE CONFLICTING MODEL GUIDANCE FOR
EXTENDED PERIODS. GOOD AGREEMENT ON SYNOPTIC SCALE PATTERN...THOUGH.
ON FRI...CYCLONE MOVES INTO MID MS RIVER VALLEY/WRN GREAT LAKES RGN
WITH ASSOCIATED SHALLOW COLD FRONT FORECAST TO MOVE INTO SERN CO.
STRONG UPPER LEVEL RIDGING CONTINUES TO BUILD INTO THE ROCKY MTNS
AS PACIFIC NW SHORTWAVE COMES ON SHORE. THE CONFLICT IN THE MODELS IS
THE DEG/DEPTH OF MOISTURE.  AVN OVERLY MOIST...ESPECIALLY AT 500MB...
ALONG THE SERN CO MTNS.  WHILE ETA IS NEARLY "BONE DRY"...RH 10-
20%...500-300MB WITHIN THE RIDGE.  COULDN'T RULE OUT DIURNAL MTN CU
WITH SOME LOW LEVEL MOISTURE STILL IN PLACE.  PLAN TO LEAN TOWARDS
ETA SOLUTION AND LEAVE PRECIPITATION MENTION OUT OF FORECAST FOR FRI.
SERN CO TEMPS WILL BE THE COOLEST AS ELY FLOW AGAIN DEVELOPS IN
ADVANCE OF SFC HIGH SLIDING INTO AND ALONG CO/KS BORDER.  ON SAT...
"MONSTER" UPPER LEVEL RIDGE MOVES INTO ROCKY MTNS WITH 500MB AND
700MB TEMPS WARMING TO -8C AND +14C TO +18C...RESPECTFULLY.  AVN
PROGGING VERY WEAK DISTURBANCES TOPPING RIDGE.  DRYLINE/TROUGH SETS
UP ALONG CO/KS BORDER...HOWEVER MID-LEVEL CAPPING INVERSION SHOULD BE
IN PLACE IN ERN CO/WRN KS. POTENTIAL FOR SHRA/TSTM WILL SOLELY RELY
ON STRENGTH OF ANY SHORTWAVES AND LOW LEVEL CONVG ZONE TO BUST
THROUGH ERN CO PLAINS CAP.  SAT CERTAINLY LOOKS WARM WITH NEAR 90F IN
LOWER AR RIVER VALLEY. NOW...AVN HAS SHORTWAVE BREAKING DOWN RIDGE ON
SUN WITH LATE DAY COLD FRONT PASSAGE AND COOLER TEMPS.  PLAN NOT TO
ALTER DAYS 4-5 AND LET DAY SHIFT MONITOR NEXT MODEL RUNS FOR ANY
CHANcGES.  DAYS 6-7...STILL IN SW-WLY FLOW.  NO CHANGES.

.PUB...NONE.

METZE

COZ058>081-301900-

SIGNIFICANT WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PUEBLO CO
1144 AM MDT WED MAY 30 2001

...SIGNIFICANT WEATHER OUTLOOK FOR SOUTHEAST AND SOUTH CENTRAL
COLORADO...

...SPOTTER ACTIVATION MAY BE NECESSARY THIS AFTERNOON FOR ONE OR TWO
MARGINALLY SEVERE THUNDERSTORMS ALONG THE INTERSTATE 25 CORRIDOR
SOUTH OF PUEBLO...

AN UPPER LEVEL DISTURBANCE IS FORECAST TO MOVE ACROSS SOUTH
CENTRAL...AND SOUTHEAST COLORADO THIS AFTERNOON.  COMBINED WITH
WEAK NORTHEAST UPSLOPE FLOW...AND RESIDUAL LOW LEVEL
MOISTURE...SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
DEVELOP THIS AFTERNOON ACROSS THE SOUTHEAST MOUNTAINS AND PLAINS.
THE ATMOSPHERE WILL BECOME MOST UNSTABLE ALONG THE EAST SLOPES
OF THE WET MOUNTAINS AND THE SANGRE DE CRISTO MOUNTAINS...
AND THE ADJACENT PLAINS SOUTHWEST OF A LINE FROM PUEBLO TO KIM.
MODERATE INSTABILITY...COMBINED WITH FAVORABLE WIND SHEAR...MAY LEAD
TO THE DEVELOPMENT OF ONE OR TWO MARGINALLY SEVERE THUNDERSTORMS IN
THIS AREA...WITH HAIL AROUND 3/4 INCH IN DIAMETER AND GUSTY WINDS TO
AROUND 58 MPH THE PRIMARY THREATS.

ELSEWHERE...THUNDERSTORMS ARE EXPECTED TO BE WEAKER...HOWEVER...HAIL
UP TO 1/2 INCH IN DIAMETER...GUSTY WINDS TO 40 MPH AND FREQUENT
LIGHTNING WILL BE POSSIBLE...ESPECIALLY IN THE PIKES PEAK REGION.

THE NATIONAL WEATHER SERVICE IN PUEBLO WOULD APPRECIATE ANY HAIL
REPORTS FROM ITS SPOTTERS ACROSS SOUTHEAST COLORADO THIS AFTERNOON.