[SWODY2] SWODY2

[SWODY2 at goshenarc.org]

ACUS02 KWNS 230558
SWODY2
SPC AC 230557

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1257 AM CDT TUE AUG 23 2005

VALID 241200Z - 251200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM MCK
HSI BIE MKC JLN BVO P28 45 W HLC MCK.

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 80 NNW
GFK GFK ABR PIR REJ MLS 70 NW ISN.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 10 WSW CZZ RAL 10 NE
DAG P38 10 E ENV 15 SW PIH 15 SW PUW 35 NNW GEG 25 N 63S ...CONT...
40 E RRT 10 W AXN 10 SE FRM COU 10 S TBN POF BNA 10 SE AND CAE FLO
35 ESE ECG ...CONT... DRT TPL FTW 10 WNW CDS PVW HOB 45 SE ELP.

...THERE IS A SLGT RISK OF SVR TSTMS WED/WED EVENING ACROSS PARTS OF
THE NRN PLAINS....

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE CENTRAL
PLAINS....

AMPLIFIED SOUTHERN BRANCH OF POLAR JET WILL PERSIST ACROSS SOUTHERN
CANADA AND THE NORTHERN TIER OF THE U.S. THROUGH THIS FORECAST
PERIOD.  PROGRESSIVENESS OF EMBEDDED PERTURBATIONS...INCLUDING
CLOSED LOW IN THE VICINITY OF THE NORTH ATLANTIC COAST...AND ANOTHER
EVOLVING CLOSED LOW OVER THE NORTHERN ROCKIES...REMAINS A SOURCE OF
CONSIDERABLE UNCERTAINTY. 

EASTERN LOW NOW APPEARS TO BE GENERALLY CUT-OFF...BUT BY
WEDNESDAY...LATEST NAM/GFS AND ENSEMBLES SUGGEST THAT THIS
FEATURE...AND TRAILING TROUGH AXIS...WILL FINALLY BEGIN TO BE FORCED
EAST OF ATLANTIC COASTAL AREAS.  UPSTREAM LOW IS FORECAST TO
GRADUALLY DEVELOP NORTHEASTWARD INTO SASKATCHEWAN...WITH A COUPLE OF
IMPULSES ROTATING AROUND ITS SOUTHERN/EASTERN PERIPHERY...ACROSS THE
NORTH CENTRAL ROCKIES AND NORTHERN U.S. PLAINS.  THIS WILL OCCUR AS
ANOTHER TROUGH DIGS TOWARD THE BRITISH COLUMBIA COAST.

FARTHER SOUTH...MODELS SUGGEST SUBTROPICAL RIDGING...CENTERED OVER
THE WESTERN/CENTRAL GULF STATES...WILL BEGIN TO EXPAND ONCE AGAIN. 
SERIES OF WAVES ROTATING AROUND ITS PERIPHERY LIKELY WILL CONTRIBUTE
TO CONVECTIVE DEVELOPMENT WEDNESDAY/WEDNESDAY NIGHT ACROSS PARTS OF
THE FOUR CORNERS REGION...AND THE CENTRAL PLAINS.

...NORTHERN PLAINS...
ALTHOUGH SURFACE BOUNDARY WILL LINGER OVER PORTIONS OF THE SOUTH
CENTRAL PLAINS INTO WEDNESDAY...MOIST EAST SOUTHEASTERLY UPSLOPE
FLOW REGIME IS ALREADY DEVELOPING ACROSS THE CENTRAL PLAINS...WHERE
DEW POINTS ARE NOW NEAR 70F.  THIS MOISTURE SEEMS MORE THAN LIKELY
TO ADVECT INTO THE NORTHERN PLAINS BY WEDNESDAY AFTERNOON...AS
SOUTHERLY FLOW STRENGTHENS EAST OF LEE SURFACE TROUGH.

PRIMARY SURFACE LOW IS PROGGED TO DEVELOP ACROSS SOUTHERN
SASKATCHEWAN WEDNESDAY.  HOWEVER...TRAILING COLD FRONT MAY BECOME A
FOCUS FOR CONVECTIVE DEVELOPMENT BY PEAK HEATING AS IT SURGES ACROSS
EASTERN MONTANA INTO WESTERN NORTH DAKOTA.  FRONT WILL GRADUALLY
MERGE WITH PRE-FRONTAL TROUGH AXIS...ALONG WHICH STRONG HEATING OF
BOUNDARY LAYER IS EXPECTED TO CONTRIBUTE TO CAPE IN EXCESS OF 2000
J/KG.

STRENGTH OF CAPPING ASSOCIATED WITH MID-LEVEL THERMAL RIDGE IS A
CONCERN...PARTICULARLY TO THE SOUTH/EAST OF THERMAL LOW FORMING OVER
WESTERN SOUTH DAKOTA.  HOWEVER...STRONGLY DIFLUENT AND DIVERGENT
UPPER FLOW FIELD OVERSPREADING NORTH DAKOTA BY LATE WEDNESDAY
AFTERNOON IS EXPECTED TO CONTRIBUTE TO MID-LEVEL UPWARD VERTICAL
MOTION...WEAKENING CAP AND SUPPORTING CONVECTIVE DEVELOPMENT.

SHEAR WILL BE MARGINALLY SUFFICIENT FOR SUPERCELLS IN INITIAL
ACTIVITY.  BUT...CONVECTIVE CLUSTER IS EXPECTED TO EVOLVE IN
ENVIRONMENT WHERE DRY MID-LEVELS WITH STEEP LAPSE RATES WILL
CONTRIBUTE TO SOUNDINGS SUPPORTIVE OF ISOLATED VERY LARGE HAIL AND
DAMAGING DOWNBURSTS.  SEVERE THREAT SHOULD CONTINUE/SLOWLY DEVELOP
SOUTHWARD WELL INTO THE EVENING HOURS...BEFORE STABILIZING BOUNDARY
LAYER WEAKENS STORMS OVERNIGHT.

...CENTRAL PLAINS...
MODELS SUGGEST CAPPING IN WAKE OF MID-LEVEL IMPULSE ASSOCIATED WITH
SUBTROPICAL STREAM MAY BE SLOW TO STRENGTHEN OVER CENTRAL KANSAS
WEDNESDAY.  THIS IS WHERE SOUTHERLY LOW-LEVEL JET IS FORECAST TO
FOCUS WARM ADVECTION ALONG/NORTH OF LINGERING SURFACE FRONT.  VERY
MOIST BOUNDARY LAYER WITH DEW POINTS AROUND 70F WILL BECOME MODERATE
TO STRONGLY UNSTABLE BY PEAK AFTERNOON HEATING... AND CAPE IN EXCESS
OF 3000 J/KG APPEARS POSSIBLE. THOUGH NOT STRONG...WESTERLY
COMPONENT TO MID-LEVEL FLOW IS EXPECTED TO CONTRIBUTE TO SUFFICIENT
SHEAR FOR A FEW SUPERCELLS...WITH LARGE HAIL/DAMAGING
WINDS...POSSIBLY ISOLATED TORNADOES.

ENTRANCE REGION OF INCREASINGLY ANTICYCLONIC HIGH-LEVEL JET STREAK
MAY SUPPORT EVOLUTION OF LARGE CONVECTIVE CLUSTER BY WEDNESDAY
EVENING.  ACTIVITY SHOULD SPREAD EAST NORTHEASTWARD TOWARD THE
MISSOURI VALLEY...AND MAY BE ACCOMPANIED BY STRONG GUSTY WINDS ALONG
OUTFLOWS...BEFORE LOCALLY HEAVY RAIN BECOMES PRIMARY THREAT
OVERNIGHT.

...GULF STATES...
VERY MOIST AIR MASS WILL PERSIST SOUTH OF SURFACE FRONT ASSOCIATED
WITH EASTERN TROUGH.  SCATTERED CONVECTIVE DEVELOPMENT WILL OCCUR
WITH DAYTIME HEATING...AND THERMODYNAMIC PROFILES BY PEAK HEATING
MAY BECOME FAVORABLE FOR HIGHLY LOCALIZED DOWNBURSTS IN
STRONGER...BUT GENERALLY SHORT-LIVED CELLS.

..KERR.. 08/23/2005

...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.