[SWODY2] SWODY2

[SWODY2 at goshenarc.org]

ACUS02 KWNS 201731
SWODY2
SPC AC 201730

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1230 PM CDT WED APR 20 2005

VALID 211200Z - 221200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 45 NW
DRT 40 N SJT ADM 45 E ICT CNK 10 NW GRI 60 NNE BUB YKN 35 SSW OTG 35
W SPW ALO MMO DNV HUF 10 N EVV HOP TUP GWO 25 N ESF LFK SAT 50 NW
LRD.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 25 SSE P07 50 ENE BGS
SPS OKC ICT MCK BFF 50 SW RAP 60 ESE REJ MBG RST SBN CMH ZZV MRB DOV
30 S ACY.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM EAT GEG 27U SUN OWY
4LW EUG OLM SEA EAT.

...THERE IS A SLGT RISK OF SVR TSTMS THU/THU NIGHT FROM THE PLAINS
INTO THE MISSISSIPPI VALLEY....

MODELS INDICATE THAT BLOCKING PATTERN WILL PERSIST THROUGH THIS
FORECAST PERIOD AND BEYOND.  HOWEVER...UPPER HIGH CENTER AND CLOSED
LOW CURRENTLY OVER THE CANADIAN ROCKIES AND INTERMOUNTAIN U.S. WILL
BREAK DOWN THURSDAY...AS A NEW HIGH CENTER BEGINS TO DEVELOP NEAR
THE BRITISH COLUMBIA COAST...AND A NEW LOW FORMS OFF THE CALIFORNIA
COAST.

MODELS ARE SIMILAR IN SUGGESTING BROAD GREAT BASIN CIRCULATION WILL
BREAK DOWN INTO A COUPLE OF SMALLER SCALE CIRCULATIONS.  ONE OF
THESE ALREADY APPEARS TO HAVE FORMED OVER SOUTHEAST IDAHO...AND IS
PROGGED TO DEVELOP WEST NORTHWESTWARD THROUGH THE COLUMBIA VALLEY BY
THURSDAY NIGHT.  THE OTHER CIRCULATION AND ASSOCIATED SHORT WAVE
TROUGH IS PROGGED TO DEVELOP EAST OF THE ROCKIES INTO THE CENTRAL
PLAINS BY EARLY THURSDAY.  SYSTEM IS THEN FORECAST TO TURN
SOUTHEASTWARD THROUGH THE MID/LOWER MISSOURI VALLEY LATER
THURSDAY/THURSDAY NIGHT...AS A SIGNIFICANT SHORT WAVE TROUGH DIGS
FROM THE CANADIAN PRAIRIES INTO THE UPPER MISSISSIPPI VALLEY.

LATTER FEATURE WILL BE PROGRESSING INTO BROADER SCALE NORTHERN
BRANCH TROUGH...WHICH WILL PERSIST ACROSS MUCH OF EASTERN CANADA AND
THE NORTHEASTERN STATES.

...PLAINS/MISSISSIPPI VALLEY...
INFLUX OF GULF MOISTURE AND STEEPENING LOW/MID-LEVEL LAPSE RATES
HAVE ALREADY CONTRIBUTED TO FAVORABLE ENVIRONMENT FOR SEVERE STORMS
ACROSS A BROAD AREA OF THE CENTRAL U.S...FROM THE LEE OF THE
CENTRAL/SOUTHERN ROCKIES INTO THE MISSISSIPPI VALLEY.  GIVEN
INCREASING LARGE-SCALE FORCING FOR UPWARD VERTICAL MOTION AND
STRENGTHENING SHEAR PROFILES ASSOCIATED WITH EVOLVING UPPER FLOW
PATTERN...POTENTIAL EXISTS FOR WIDESPREAD CONVECTIVE DEVELOPMENT
THURSDAY/ THURSDAY NIGHT.

MOST EXTENSIVE ACTIVITY APPEARS LIKELY IN ASSOCIATION WITH STRONGER
MID-LEVEL FORCING...FROM THE MIDDLE INTO LOWER MISSOURI VALLEY. 
STORMS ALSO APPEAR LIKELY TO BECOME NUMEROUS IN ZONE OF ENHANCED
WARM ADVECTION...FROM THE OZARKS SOUTHWARD THROUGH EASTERN OKLAHOMA
AND THE ARKLATEX INTO PARTS OF CENTRAL TEXAS.  SOUTHWESTERN LIMIT TO
CONVECTIVE THREAT IS SOMEWHAT UNCERTAIN... PRIMARILY DUE TO FORECAST
AMPLIFICATION OF HIGH LEVEL RIDGE IN SOUTHERN BRANCH OF THE
WESTERLIES...FROM THE SOUTHERN U.S./MEXICAN PLATEAU INTO TEXAS.

CLUSTER OF CONVECTION MAY BE ONGOING AT 12Z THURSDAY ACROSS THE MID
MISSOURI VALLEY...IN ASSOCIATION WITH FORCING EAST OF LOW/MID- LEVEL
CYCLONE.  THIS ACTIVITY SHOULD TEND TO DEVELOP EAST SOUTHEASTWARD
ALONG DEVELOPING WARM FRONTAL ZONE TOWARD THE LOWER OHIO
VALLEY...BUT COULD STABILIZE BOUNDARY LAYER THROUGH BROAD PORTION OF
THE EAST CENTRAL PLAINS/LOWER MISSISSIPPI VALLEY DURING THE DAYTIME
HOURS. THIS PROVIDES PRIMARY UNCERTAINTY WITH REGARD TO MORE
INTENSE CONVECTIVE THREAT...INCLUDING RISK OF TORNADIC
SUPERCELLS...DURING THIS FORECAST PERIOD.  HOWEVER...POTENTIAL FOR
AT LEAST LARGE HAIL WILL ENCOMPASS A BROAD AREA FROM THE CENTRAL/
SOUTHERN PLAINS INTO THE MID/LOWER MISSISSIPPI VALLEY...AND WILL
PERSIST THROUGH THURSDAY NIGHT.

...SOUTHERN APPALACHIANS...
BOUNDARY LAYER WILL REMAIN RATHER DRY TO THE LEE OF THE HIGHER
TERRAIN...SOUTH OF COLD FRONT ADVANCING SOUTHWARD THROUGH THE MID
ATLANTIC COAST STATES. HOWEVER...STEEP LAPSE RATE ENVIRONMENT WILL
DEVELOP AND COULD BECOME SUPPORTIVE OF ISOLATED HAIL/WIND THREAT BY
LATE THURSDAY AFTERNOON.  CONVECTIVE POTENTIAL COULD BECOME ENHANCED
BY IMPULSE EMBEDDED WITHIN DEVELOPING WEAK NORTHWESTERLY MID/UPPER
FLOW REGIME.

..KERR.. 04/20/2005

...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.