Lightning Strike in Colorado, July 11, 2001

SOUTH CENTRAL AND SOUTHEAST COLORADO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PUEBLO COLORADO
214 PM MDT WED JUL 11 2001

...POTENTIAL MOD-HEAVY RAIN EVENT SERN CO MTNS/PLAINS THU NGT...

CURRENTLY: LATEST WATER VAPOR IMAGERY AND 12Z/11 UPPER AIR ANALYSES
SHOWED DEEPEST MOISTURE LAYER STILL ALONG THE WRN PERIPHERY OF LARGE
UPPER LEVEL ANTICYCLONE CENTERED OVER OK.  THIS MOISTURE AXIS EXTENDS
FROM THE DESERT SW INTO GREAT BASIN THROUGH NRN CO INTO NRN/CNTRL
PLAINS.  HARD TO DISCERN ANY MID LEVEL SHORTWAVE TROUGHS MIGRATING
OUT OF NM PER WATER VAPOR IMAGERY/RUC MODEL ANALYSES. CU/TCU STARTING
LATER AND LESS IMPRESSIVE THAN YDA ACROSS THE RGN. SHRA/TSTM COVERAGE
LESS THAN YDA...TOO.  SFC DEW POINTS STARTING TO MIX OUT AND HAVE
DROPPED 5-10F PER SERN CO METARS AND SERN CO MTN RAWS STATIONS.
18Z/11 SFC ANALYSIS HAD QUASI-STATIONARY FRONT EXTENDED FROM NRN CO
FOOTHILLS TO KLIC TO JUST N OF KLAA TO KHLC TO KCNK.  THERMAL LOW WAS
NEAR SERN CO AROUND KEHA.

MODELS MAY BE TRYING TO SCOUR OUT LOW LEVEL MOISTURE TOO MUCH...SO
THIS AFTN/EVE CAPE VALUES IN SERN CO MAY BE AROUND 1-2K J/KG.  JUST
NEED A SHORTWAVE OR LOW LEVEL CONVG BOUNDARY FOR TSTM INITIATION...
DON'T SEE IT YET.

TNGT-THU: PLAN TO MAKE THE SHRA/TSTM COVERAGE CALL JUST BEFORE PRESS
TIME AFTER REVIEWING SATELLITE/RADAR/KINEMATIC TRENDS.  ACTIVITY
SHOULD MAINLY BE DIURNAL.  NOCTURNAL MCS POTENTIAL MAY BE FURTHER E-
NE TNGT.  S-SWLY 30-40KT LLJ DEVELOPS OVER TX/OK PANHANDLES AROUND
06Z/11.  850MB CONVG BULLSEYE PROGGED OVER NWRN/N CNTRL KS LATER
TNGT.  BEST 850-700MB WAA/THETA-E ADVECTION FORECAST OVER KS INTO ERN
NE BY MIDNIGHT.  LLJ FORECAST TO VEER WITH TIME...SO POTENTIAL
NOCTURNAL MCS OVER CNTRL PLAINS SHOULD FORWARD PROPAGATE INTO MID MS
RIVER VALLEY. MCS INITIATION IS IMPORTANT FOR SERN CO AS ANY OUTFLOW
BOUNDARIES COULD CONTINUE SHRA/TSTM POTENTIAL AND/OR INCREASE LOW
LEVEL MOISTURE.  MUCH OF THE SAME FOR THU.  LOW LEVEL ELY FLOW
DEVELOPS LIKELY IN RESPONSE TO DIFFERENTIAL HEATING (MTN/PLAINS
CIRCULATIONS) AND MID LEVEL SHORTWAVE ENTERING INTO EXTREME WRN CO
THU AFTN. POTENTIAL FOR LATE AFTN/EVE SEVERE WX MAY EXIST IN SERN
CO...MAINLY FOR 3/4 INCH HAIL AND DAMAGING WINDS. 0-6KM SHEAR WEAK AT
BEST...AROUND 25KTS.  THINK SPC'S DAY 2 SLIGHT RISK IS MORE FOR THU
NGT.  WILL CONTINUE CHANCE POPS FOR THU.  PERSISTENCE THE BEST WAY TO
GO FOR MIN/MAX TEMPS.

THU NGT-FRI NGT: POTENTIAL FOR MOD-HEAVY RAIN ACROSS SERN CO MTNS/
PLAINS THU NGT.  MOST OF THE MADDOX TYPE 1 HEAVY RAIN CONCEPTUAL
MODEL PARAMETERS ARE COMING TOGETHER...AT LEAST DEPICTED BY THE
MODELS.  ALL SHORT RANGE MODELS SUGGESTING THIS PATTERN.  THEY ARE AS
FOLLOWS...

     1. UPPER HIGH CENTERED OVER TX PANHANDLE WITH RIDGE OVER ERN CO
     2. A COUPLE OF MID LEVEL SHORTWAVES ENTERING WRN CO OVER HIGH
     3. QUASI-STATIONARY FRONT ALONG FRONT RANGE-NERN NM-TX/OK
     4. 25-35KT ELY LLJ OVER SERN CO/SWRN KS BY 06Z/13 (OROGRAPHICS)
     5. WK-MOD 700MB WAA OVER SERN CO
     6. EDGE OF MID LEVEL "CAP" (700MB +10 TO +12C) OVER SRN CO
     7. 700MB DEW POINTS 6-8C WITH 850-700 THETA RIDGES OVER SERN CO
     8. 55-65F SFC DEW POINTS ADVECT INTO SERN CO
     9. PRECIPITABLE WATER INDICES 1-1.6"(AT LEAST 150% OF NORMAL)
    10. GEORGE'S K-INDICES 35-45C ALONG SERN CO MTNS/PLAINS
    11. MUCAPES 250-1500 J/KG "FEEDING" INTO POTENTIAL MCS

THE HEAVY RAIN EVENT POTENTIAL WOULD RELY ON THE STEERING CURRENT
STRENGTH.  CURRENTLY...500MB WINDS PROGGED TO BE WLY 20-25KTS WHICH
COULD LESSEN THE HEAVY RAIN THREAT. HOWEVER...ANY ECHO TRAINING...OR
WEAKER STEERING CURRENTS....WOULD SIGNIFICANTLY INCREASE THE HEAVY
RAIN THREAT PRODUCING 1-2 INCHES...AND PERHAPS LOCALLY 3 INCHES. ALSO
PATTERN WILL NEED TO RELY ON MESO-SCALE SETUP...WHICH IS HARD TO
PINDOWN OUT 24-36HRS. COULD BE A LATE NGT SEVERE WEATHER THREAT IN
SERN CO THU NGT. 0-6KM SHEAR PROGGED TO BE 35-41KTS WITH 0-3KM
HELICITY OF 150-250 M2/S2...SO PARAMETERS MAY BE IN PLACE FOR MESO-
CYCLONE DEVELOPMENT.  PLAN TO BUMP POPS UP TO "LIKELYS" (60-70%) FOR
SERN CO MTNS/PLAINS ON THU NGT. MOS GUIDANCE POPS LOOK A LITTLE TOO
LOW. POTENTIAL MCS SHOULD MIGRATE EWD INTO CNTRL PLAINS LATE THU
NGT/FRI AM.  LIKE NCEP'S DAY 2 AREAL AVE QPF FOR SERN CO. ANTECEDENT
CONDITIONS ARE PRETTY DRY IN SERN CO PLAINS.  WAY TOO EARLY FOR ANY
FLASH FLOOD WATCHES.  WILL MENTION "LOCALLY HEAVY RAIN" FOR SERN CO
MTNS/PLAINS DURING THU NGT.

ON FRI...POTENTIAL THU NGT MCS SHOULD DEFINITELY PRIME THE AIR MASS
WITH "JUICE."  UPPER LEVEL HIGH FORECAST TO SHIFT SWWD INTO NM BY FRI
AFTN.  RESIDUAL CONVECTIVE DEBRIS CLOUDS...ESPECIALLY LOW LEVEL
IN SERN CO...SHOULD BE OVER MUCH OF SRN CO FRI AM.  AIR MASS RECOVERY
WILL BE CRITICAL FOR SHRA/TSTM DEVELOPMENT/INTENSITY.  WITH 500MB
HIGH FORECAST OVER NM...THIS WILL PUT SRN CO IN THE SHORTWAVE
"TRAFFIC LANE" FRI AFTN/NGT.  K-INDICES PROGGED TO BE 40-45C.  WILL
GO WITH "HIGH" CHANCE POPS (50%) FOR FRI IN MOST AREAS...AND AGAIN
"LIKELYS" (60-70%) FOR SERN CO MTNS/PLAINS FOR FRI NGT.   FRI'S MAX
TEMPS SHOULD BE A LITTLE COOLER GIVEN CLOUD COVER AND PRECIPITATION.

EXTENDED(SAT-WED): EFP WAS CHANGED DURING THE 'MIDSHIFT...SO CERTAINLY
WON'T CHANGE ANYTHING FURTHER. JUST ADDED "WEDNESDAY." IT'S JULY IN
THE ROCKIES.

PUB...NONE.

METZE