ZCZC SPCSWODY1 ALL
ACUS01 KWNS 080559
SPC AC 080559

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1259 AM CDT FRI AUG 08 2003

VALID 081200Z - 091200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 70 NNW
GFK GFK HON 9V9 CDR 10 E 81V 4BQ BIL GTF 65 ENE CTB

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 45 ESE 7R4 GPT 60 NNW
PNS SEM 10 SE UOX PAH 10 SE LAF BEH 25 E MTW 70 NNW ANJ

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 10 ESE CZZ DAG BIH 50
E LOL EKO 10 NNE BOI BKE RDM OLM 15 NE BLI ...CONT... RRT FAR MHE
GRI SLN 10 SSE BVO FSM TXK GGG 25 ESE BPT ...CONT... 55 SW MRF BGS
AMA 25 NNW CVS ONM SVC 40 SW DMN

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON AND EVENING FROM
PARTS OF CNTRL/ERN MONTANA INTO THE DAKOTAS....

MODELS SUGGEST CLOSED LOW WILL REMAIN CUT-OFF FROM POLAR WESTERLIES
...OFF THE PACIFIC NORTHWEST COAST THROUGH THIS FORECAST PERIOD. 
DOWNSTREAM...WEAK LOW/MID-LEVEL FLOW REGIME WILL PERSIST BENEATH
HIGH AMPLITUDE LARGE-SCALE RIDGE/TROUGH PATTERN EMBEDDED WITHIN
SUBTROPICAL BRANCH OF THE WESTERLIES ACROSS THE U.S.

...MONTANA INTO THE DAKOTAS...
WEAK MID/HIGH-LEVEL SHORT WAVE TROUGH AND ASSOCIATED SUBTROPICAL JET
STREAK EMANATING FROM THE LOWER LATITUDE PACIFIC HAS LIFTED AHEAD OF
CLOSED LOW INTO THE NORTHERN INTERMOUNTAIN REGION.  THIS FEATURE IS
PROGGED TO CONTINUE MIGRATING AROUND CREST OF HIGH PLAINS UPPER
RIDGE...AND APPEARS LIKELY TO PROGRESS ACROSS EASTERN MONTANA INTO
WESTERN NORTH DAKOTA NEAR/SHORTLY AFTER PEAK HEATING.  ASSOCIATED
LARGE-SCALE FORCING FOR UPWARD VERTICAL MOTION IS EXPECTED TO
SUPPORT EVOLUTION OF INTENSE CONVECTIVE CLUSTER BY EARLY EVENING
OVER WESTERN NORTH DAKOTA.  INITIAL CLUSTER APPEARS LIKELY TO SPREAD
EASTWARD WITH UPPER FORCING ACROSS THE REMAINDER OF NORTH DAKOTA
OVERNIGHT...BUT THIS ACTIVITY LIKELY WILL WEAKEN WITH BETTER INFLOW
OF MOIST/UNSTABLE AIR BECOMING FOCUSED ON NOSE OF LOW-LEVEL JET
ACROSS WESTERN SOUTH DAKOTA...WHERE PRIMARY CLUSTER OF STORMS
APPEARS LIKELY BY 09/12Z.

MODELS SUGGEST ENVIRONMENT WILL BECOME STRONGLY UNSTABLE ACROSS THE
NORTHERN HIGH PLAINS BY THE TIME OF CONVECTIVE INITIATION DURING THE
LATE AFTERNOON HOURS.  BETTER LOW-LEVEL MOISTURE AND STRONGEST
INSTABILITY WILL BECOME FOCUSED ALONG/JUST EAST OF THE NORTH DAKOTA
/MONTANA BORDER...IN LOW-LEVEL SOUTHEASTERLY FLOW TO THE NORTHEAST
OF WEAK SURFACE LOW.  MEAN MIXED LAYER CAPE IS PROGGED TO EXCEED
3000 J/KG...SUPPORTIVE OF STRONG UPDRAFTS.  THOUGH MID-LEVEL
WESTERLIES WILL BE FAIRLY WEAK...VEERING PROFILES WILL PROVIDE
SUFFICIENT SHEAR FOR FEW SUPERCELLS...ENHANCING THREAT FOR ISOLATED
VERY LARGE HAIL.

ISOLATED DOWNBURSTS WILL ALSO BE POSSIBLE...BUT PRIMARY DAMAGING
WIND THREAT APPEARS LIKELY DURING THE EVENING HOURS.  LOW MEAN
RELATIVE HUMIDITIES IN LOWER/MID-LEVELS WILL CONTRIBUTE TO STRONG
EVAPORATIVE COOLING IN DOWNDRAFTS ASSOCIATED WITH EVOLVING
CONVECTIVE CLUSTER ACROSS WESTERN NORTH DAKOTA.  A SUBSTANTIAL
SURFACE COLD POOL/MESO HIGH APPEARS LIKELY TO FORM...SURGING
EASTWARD INTO CENTRAL NORTH DAKOTA.  WESTERN FLANK OF OUTFLOW SHOULD
SPREAD MORE SLOWLY SOUTHWARD INTO WESTERN SOUTH DAKOTA...WHERE
ENHANCED WARM ADVECTION ON NOSE OF LOW-LEVEL JET WILL SUPPORT NEW
CONVECTIVE DEVELOPMENT WITH POTENTIAL FOR LARGE HAIL INTO THE
OVERNIGHT HOURS.

...CENTRAL HIGH PLAINS...
LEE SURFACE TROUGH ACROSS EASTERN COLORADO MAY BECOME FOCUS FOR
ANOTHER CONVECTIVE CLUSTER LATE THIS AFTERNOON AND TONIGHT.  AIR
MASS IS PROGGED TO BECOME MODERATE TO STRONGLY UNSTABLE ACROSS THIS
REGION WITH DAYTIME HEATING...AND MEAN MIXED LAYER CAPE OF 2000 TO
3000 J/KG IS PROGGED BY THE TIME STRONGER MID/UPPER FORCING FOR
UPWARD VERTICAL MOTION SHIFTS EAST OF THE FRONT RANGE THIS
AFTERNOON.  THIS FORCING WILL BE IN RESPONSE TO WEAK SHORT WAVE NOW
PROGRESSING NORTHEASTWARD THROUGH THE COLORADO VALLEY INTO THE
EASTERN GREAT BASIN...AND PROGGED TO CONTINUE SLOWLY AROUND
SUBTROPICAL RIDGE CENTER...ACROSS THE CENTRAL ROCKIES INTO THE
CENTRAL HIGH PLAINS BY THE END OF THE FORECAST PERIOD. DESPITE
STRONG VEERING OF WINDS WITH HEIGHT IN LOWER/MID-LEVELS... OVERALL
SHEAR PROFILES ARE PROGGED TO REMAIN RATHER WEAK.  THIS... IN
CONJUNCTION WITH RELATIVELY WARM AND MOIST THERMODYNAMIC
PROFILES...IS EXPECTED TO MINIMIZE EXTENT OF SEVERE THREAT.

...EASTERN GULF/SOUTH ATLANTIC COAST STATES/FLORIDA PENINSULA...
MOIST LOW-LEVEL ENVIRONMENT...WEAK CAPPING...AND DIFFLUENT/
DIVERGENT UPPER FLOW REGIME EAST OF UPPER TROUGH AXIS IS EXPECTED TO
SUPPORT SCATTERED CONVECTIVE DEVELOPMENT THIS AFTERNOON AND EVENING.
 ACTIVITY APPEARS LIKELY TO BECOME FOCUSED ALONG EAST COAST FLORIDA
SEA BREEZE...AND LOW-LEVEL THERMAL RIDGE AXIS FROM SOUTHEAST ALABAMA
INTO CENTRAL NORTH CAROLINA...WHERE STRONG SURFACE HEATING WILL
CONTRIBUTE TO INSTABILITY.  OVERALL DESTABILIZATION WILL BE LIMITED
BY WEAK MID-LEVEL LAPSE RATES...AND WEAK FLOW/SHEAR REGIME IS
EXPECTED TO LIMIT SEVERE THREAT TO VERY ISOLATED...PULSE TYPE SEVERE
EVENTS.

..KERR/BRIGHT.. 08/08/2003

...NOTICE...
FOR USERS DECODING THE POINTS PARAGRAPH HEREIN...LATITUDE AND
LONGITUDE POINTS FOR THE CATEGORICAL AND PROBABILISTIC OUTLOOK
GRAPHICS ALSO ARE LOCATED IN A SEPARATE PRODUCT UNDER THE WMO
HEADINGS WUUS01 PTSDY1...WUUS02 PTSDY2...AND WUUS03 PTSDY3.  THE
INCLUSION OF POINTS IN THIS PRODUCT WILL EVENTUALLY BE DISCONTINUED.

$$