[SWODY1] SWODY1

[SWODY1 at goshenarc.org]

ACUS01 KWNS 200558
SWODY1
SPC AC 200557

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1257 AM CDT FRI MAY 20 2005

VALID 201200Z - 211200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM RRT
BJI AXN BKX MHE 9V9 RAP 81V GCC SHR BIL 3HT LWT ISN MOT 75 NNW DVL.

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 30 S
GPT MCB HEZ MLU 40 W GLH 35 ENE JBR 40 W HOP BWG CSV CHA RMG ATL MCN
ABY AQQ.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 80 E ELO MSP FOD FNB
SLN 40 SSW DDC EHA LHX 4FC OWY 4LW 4BK.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM GLS 25 ESE CLL 50 W
TYR 45 N PRX 45 SE TBN MVN CMH AOO ACY.

...THERE IS A SLGT RISK OF SVR TSTMS TN VALLEY TO MIDDLE GULF
COAST...

...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS NRN PLAINS...

...SYNOPSIS...
MOST PROMINENT SYNOPTIC FEATURE FOR THIS FCST PERIOD WILL BE SHARPLY
DEFINED RIDGE FROM HUDSON BAY AREA SWWD ACROSS MN AND CENTRAL
PLAINS....TO HIGH OVER SRN NM/NRN CHIHUAHUA.  MEANWHILE BROAD UPPER
CYCLONE NOW OFFSHORE CANADIAN MARITIMES SHOULD RETROGRADE WWD/SWWD
OVER NEW ENGLAND. AS HEIGHT GRADIENT TIGHTENS BETWEEN MARITIMES LOW
AND CENTRAL CONUS RIDGE...SHORTWAVE TROUGH -- NOW EVIDENT IN
MOISTURE CHANNEL IMAGERY OVER NERN IL -- WILL ACCELERATE SEWD TOWARD
SRN ATLANTIC COAST BY END OF PERIOD.  MEANWHILE...SHORTWAVE TROUGH
NOW OFFSHORE WA/ORE IS EXPECTED TO LIFT NEWD ACROSS PACIFIC NW AND
NRN ROCKIES...REACHING CENTRAL/ERN MT BY 21/12Z.

SFC PATTERN WILL BE CONSIDERABLY MORE JUMBLED THAN THAT
ALOFT...ESPECIALLY E OF MS RIVER.  ONGOING CONVECTIVE COMPLEXES FROM
ERN KY TO NRN TN...AND APCHG LOWER OH VALLEY FROM IL/INDIANA -- WILL
STRONGLY INFLUENCE/ADJUST LOCATION OF DAY-1 SEVERE POTENTIAL THROUGH
RESULTANT OUTFLOW/DIFFERENTIAL HEATING BOUNDARIES AND PERHAPS
MIDLEVEL MCV FEATURES. SYNOPTIC FRONT ASSOCIATED WITH NW-FLOW
SHORTWAVE ALOFT WILL MOVE SWD OVER MID-SOUTH AND OZARKS
REGION...BECOMING QUASISTATIONARY NWWD ACROSS KS/NEB...THEN WARM
FRONT OVER DAKOTAS...CONNECTING WITH LEE-SIDE CYCLOGENESIS OVER NRN
HIGH PLAINS.  SFC LOW DEEPENING SHOULD OCCUR THROUGHOUT DAYLIGHT
HOURS OVER ERN MT/NERN WY AREA BENEATH SWLY FLOW ALOFT...AND W OF
MEAN RIDGE POSITION.  ASSOCIATED LOW LEVEL FORCING WILL INCLUDE
STRONG WAA ACROSS NRN PLAINS THROUGHOUT PERIOD...AND 50-60 KT LLJ
AFTER DARK OVER PORTIONS DAKOTAS.

...TN VALLEY TO MIDDLE GULF COAST...
SEVERE POTENTIAL IS STRONGLY DEPENDENT ON ORIENTATION AND STRENGTH
OF MESOSCALE FEATURES YET TO DEVELOP.  HOWEVER...GREATEST
COMBINATION OF BUOYANCY AND VERTICAL SHEAR IS PROGGED FROM MID TN
SWD INTO CENTRAL/WRN AL AND NERN/E-CENTRAL MS THIS
AFTERNOON...POSSIBLY ENHANCED BY CONVECTIVE BOUNDARIES.
TSTMS SHOULD DEVELOP DURING AFTERNOON AND/OR PERSIST/INTENSIFY FROM
MORNING ACTIVITY...WITH STRONG PROPAGATIONAL COMPONENT RESULTING IN
SWD MOTION ACROSS REGION.

SFC DEWPOINTS MID 60S F...WITH POCKETS INTO LOW 70S...WILL COMBINE
WITH DIABATIC HEATING IN CLOUD-FREE AREAS TO YIELD MLCAPES 1500-2500
J/KG.  STRONG VEERING WITH HEIGHT AND FAVORABLY LARGE LOW LEVEL FCST
HODOGRAPH YIELD 0-1 KM AGL SRH VALUES EXCEEDING 200 J/KG...FROM
CENTRAL AL TO SRN MID TN.  THIS...IN COMBINATION WITH POTENTIAL FOR
RIGHTWARD DEVIANCE ALONG BOUNDARIES AND LOW LCL...INDICATE SOME
TORNADO POTENTIAL WITH DISCRETE STORMS.  SHEAR/BUOYANCY PROFILES
ALSO WILL SUPPORT SWD TO SSWWD MOVING MCS WITH DAMAGING GUSTS AND
LARGE HAIL.  ACTIVITY MAY REACH AS FAR AS GULF COAST BEFORE
DIMINISHING THIS EVENING.

...NRN PLAINS/UPPER MIDWEST...
ISOLATED TO WIDELY SCATTERED TSTMS ARE EXPECTED TO DEVELOP OVER
HIGHER TERRAIN OF SERN MT AND ADJACENT HIGH PLAINS OF WRN ND/NWRN SD
THIS AFTERNOON...IN VERTICAL SHEAR PROFILE FAVORABLE FOR SUPERCELLS
AND BOWS.  LARGE/DAMAGING HAIL AND SEVERE GUSTS BOTH ARE POSSIBLE. 
MCS FROM EVENING ONWARD MAY CONCENTRATE WIND THREAT WITH HAIL
REMAINING A THREAT.

LOW LEVEL MOISTURE IS EXPECTED TO BE PRIMARY WEAKNESS INITIALLY. 
SFC DEW POINTS 40S/50S F AND STRONG HEATING SHOULD YIELD HIGH CLOUD
BASES AND DEEPLY MIXED BOUNDARY LAYERS...SUPPORTING MAINTENANCE TO
SFC OF SEVERE HAIL/DOWNDRAFTS GENERATED ALOFT. STEEP MIDLEVEL LAPSE
RATES SHOULD OFFSET LACK OF LOW LEVEL MOISTURE ENOUGH TO YIELD
1000-2000 J/KG MLCAPES...THOUGH CAPPING MAY LIMIT COVERAGE OF
DAYTIME TSTMS. SLY/SELY LOW LEVEL FLOW AND 40-50 KT WSW FLOW AT 500
MB WILL CONTRIBUTE TO 0-6 KM SHEARS AS HIGH AS 65-75 KT.  FLOW WILL
BECOME PROGRESSIVELY MORE BACKED FROM WRN DAKOTAS WNWWD INTO ERN
MT...AROUND NRN SEMICIRCLE OF SFC CYCLONE...YIELDING LARGE
HODOGRAPHS WITH 0-3 KM SRH POSSIBLY EXCEEDING 200 J/KG.

STRONG AND REASONABLE SIGNAL EXISTS IN SEVERAL SHORT-RANGE MODELS
FOR MCS DEVELOPMENT AFTER 21/00Z -- PROBABLY EVOLVING FROM ERN
MT/WRN ND CONVECTION DURING EVENING AND ORGANIZING INTO WIND DAMAGE
PRODUCING SYSTEM ACROSS ND OVERNIGHT.  STRONG LOW LEVEL WAA AND
MOISTURE TRANSPORT WILL ACCOMPANY INTENSIFYING LLJ...ALLOWING
FAVORABLE STORM-RELATIVE INFLOW AMIDST ENVIRONMENT OF 1000-1500 J/KG
ELEVATED MUCAPE.

...SRN APPALACHIANS/PIEDMONT TO CAROLINAS COASTAL PLAIN...
SEVERE WIND AND MARGINAL HAIL POTENTIAL MAY DEVELOP OVER THIS AREA
LATE MORNING INTO AFTERNOON -- BUT THREAT IS TOO CONDITIONAL ATTM TO
 WARRANT HIGHER PROBABILITIES FOR CATEGORICAL OUTLOOK.
REMNANTS OF ONGOING CONVECTION ACROSS WV...TN AND ERN KY SHOULD BE
MOVING EWD ACROSS THIS REGION EARLY IN PERIOD. ACTIVITY MAY
CONTINUE/REINTENSIFY..OR NEW DEVELOPMENT MAY OCCUR ALONG RESIDUAL
CONVECTIVE BOUNDARY OVER THIS AREA.  FOREGOING AIR MASS ACROSS
PIEDMONT AND COASTAL PLAIN WILL BE RELATIVELY MOIST COMPARED TO
HIGHER ELEVATIONS FARTHER W...WITH LOW LEVEL MOISTURE NOW OVER SRN
GA ADVECTING NEWD INTO THIS REGION.

POTENTIAL EXISTS FOR STRONG DIURNAL SFC HEATING OVER ANY RELATIVELY
CLOUD FREE AREAS...YIELDING MLCAPES 1000-2000 J/KG. 
HOWEVER...REMNANT CLOUD DEBRIS FROM AFOREMENTIONED COMPLEX...AND/OR
ACTIVITY FARTHER SW ACROSS MS/AL/TN -- MAY PREVENT SIGNIFICANT SFC
HEATING.  ALSO...PROGGED WEAKNESS OF LOW-MIDLEVEL SHEAR PROFILES MAY
LIMIT ORGANIZATION OF ANY CONVECTION THAT DOES OCCUR.

..EDWARDS.. 05/20/2005

...NOTICE...
THE STATION RELATIVE POINTS IN THIS PRODUCT ARE NOW AVAILABLE
SEPARATELY UNDER THE WMO HEADINGS WUUS01 PTSDY1...
WUUS02 PTSDY2...WUUS03 PTSDY3.  THE INCLUSION OF POINTS
IN THIS DISCUSSION WILL BE DISCONTINUED AFTER THE 2005
CONVECTIVE SEASON.  A PUBLIC NOTIFICATION STATEMENT (PNS)
WILL PROVIDE DETAILS ON THE TRANSITION.