[SWODY1] SWODY1

[SWODY1 at goshenarc.org]

ACUS01 KWNS 202001
SWODY1
SPC AC 201959

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0259 PM CDT WED APR 20 2005

VALID 202000Z - 211200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 30 SE
P07 40 WNW SJT BGS LBB 20 WNW GAG DDC 55 NNE GCK 30 NE COS LAR BFF
AIA VTN SUX 30 E MMO FDY JHW 10 SW ROC UCA MWN 25 NNW PWM ORH POU
CXY SDF 40 ESE TBN 10 S CNU BVO 45 SSW TUL 10 S ADM 35 ESE SPS BWD
50 SSE DRT.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 30 NNE ART PBG BML 30
NW EPM ...CONT... 25 E CRE FLO HKY TRI TYS CHA HSV 50 NNW MEI 20 NW
JAN 35 ESE MLU HEZ MCB 10 NE BVE ...CONT... 20 SSW P07 MAF 25 NW LBB
AMA 10 E LBL EHA TAD 45 SE GUC 4BL 10 SE SGU P38 45 ESE ELY SLC 20
SE PIH 15 NNE SUN 27U BTM BIL PHP MHE FRM JVL SBN 20 S DTW.

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTN AND TONIGHT FROM
PARTS OF THE CNTRL/SRN PLAINS INTO THE MID MS VALLEY...AS WELL AS
FROM THE LWR OH VLY INTO NEW ENGLAND....

...NEW ENGLAND INTO LOWER OHIO VALLEY...
AMPLIFICATION OF UPPER RIDGE AXIS...NORTH OF BLOCKING RIDGE OVER THE
CANADIAN ROCKIES...IS EVIDENT IN LATEST WATER VAPOR IMAGERY.  AS
THIS PROCESS CONTINUES...DOWNSTREAM SHORT WAVE DIGGING ACROSS
SASKATCHEWAN/MANITOBA WILL CONTRIBUTE TO AMPLIFICATION OF EASTERN
CANADIAN/NORTHEASTERN U.S. UPPER TROUGH.  THIS WILL BE ACCOMPANIED
BY SOUTHWARD SURGE OF SURFACE COLD FRONT THROUGH THE GREAT LAKES
REGION INTO NORTH ATLANTIC COASTAL AREAS AND THE OHIO VALLEY BY 12Z
THURSDAY.

AHEAD OF SURFACE FRONT...AIR MASS HAS HEATED TO NEAR OR IN EXCESS OF
80F FROM THE LOWER OHIO VALLEY THROUGH NEW ENGLAND...WITH A
CONTINUED EASTWARD RETURN OF LOW-LEVEL MOISTURE AROUND RETREATING
RIDGE OFF THE SOUTH ATLANTIC COAST.  ALTHOUGH BETTER MOISTURE HAS
NOT SPREAD EAST OF THE NORTHERN APPALACHIANS...STRONGER FLOW IN BASE
OF AMPLIFYING UPPER TROUGH WILL CONTRIBUTE TO DAMAGING WIND THREAT
WITH ONGOING INCREASING CONVECTIVE DEVELOPMENT FROM PENNSYLVANIA
INTO NEW ENGLAND.  THIS ACTIVITY IS EXPECTED TO DIMINISH FAIRLY
QUICKLY AFTER DARK AS CURRENT DEEP MIXED BOUNDARY LAYER MODIFIES.

PRE-FRONTAL CONVERGENCE BAND EXTENDS WESTWARD INTO THE LOWER OHIO
VALLEY...WITH REMNANTS OF EARLY MORNING CONVECTIVE CLUSTER TO THE
WEST/SOUTHWEST...ACROSS EASTERN MISSOURI.  THESE FEATURES HAVE
PROVIDED FOCUS FOR INCREASING CONVECTIVE DEVELOPMENT IN AIR MASS
WITH MIXED LAYER CAPE UP TO 1000 J/KG. THOUGH MEAN WIND FIELDS ARE
A BIT WEAKER ACROSS THIS AREA...POTENTIAL FOR DOWNBURSTS EXISTS IN
STRONGER CELLS...AND CONSOLIDATING OUTFLOWS MAY CONTRIBUTE TO A BIT
MORE ORGANIZED WIND THREAT SOUTHWARD INTO THE OHIO VALLEY THROUGH
MID EVENING.

...CENTRAL PLAINS...
QUASI-STATIONARY SURFACE FRONT EXTENDING EAST-WEST ACROSS PARTS OF
SOUTHERN NEBRASKA/NORTHERN KANSAS IS EXPECTED TO PROVIDE PRIMARY
FOCUS FOR INTENSE CONVECTIVE DEVELOPMENT.  MOIST UNSTABLE AIR MASS
IN BOUNDARY LAYER SOUTH OF FRONT...AND ABOVE FRONTAL ZONE... BENEATH
STEEP MID-LEVEL LAPSE RATES...IS SUPPORTING CAPE IN EXCESS OF 2000
J/KG.  SHEAR PROFILES ARE SUFFICIENT FOR SUPERCELLS...AND ISOLATED
CONVECTIVE DEVELOPMENT IS POSSIBLE VICINITY OF FRONT ...AND
DEVELOPING WEST CENTRAL KANSAS SURFACE LOW...AS EARLY AS LATE
AFTERNOON.

BETTER FORCING FOR UPWARD VERTICAL MOTION WILL AWAIT SHORT WAVE
TROUGH LIFTING OUT OF THE FOUR CORNERS REGION. THIS APPEARS LIKELY
TO OCCUR IN THE 21/00-06Z TIME FRAME...WHEN INITIATION OF LARGE
CONVECTIVE CLUSTER APPEARS LIKELY TO OCCUR.  ACTIVITY SHOULD PERSIST
WITH RISK OF LARGE HAIL/DAMAGING WINDS THROUGH THE OVERNIGHT
HOURS...AS IT SPREADS EASTWARD ALONG FRONT TOWARD THE LOWER MISSOURI
VALLEY.

...SOUTHERN PLAINS...
BOUNDARY LAYER ALONG DRY LINE IS MOIST AND HAS BECOME CONDITIONALLY
MODERATELY UNSTABLE WITH SURFACE HEATING.  GIVEN STRONG
CAPPING...LACK OF BETTER FORCING WILL LIMIT COVERAGE OF ANY
DEVELOPING THUNDERSTORM ACTIVITY.  HOWEVER...IT STILL APPEARS THAT
DIFLUENT AND AT LEAST WEAK DIVERGENT UPPER FLOW REGIME IS BECOMING
FOCUSED BETWEEN UPPER JETS ACROSS PARTS OF NORTHWEST TEXAS/SOUTHWEST
OKLAHOMA.  THIS MAY PROVIDE BEST CHANCE FOR ISOLATED SUPERCELL
DEVELOPMENT LATE THIS AFTERNOON...WHICH SHOULD PERSIST INTO AT LEAST
EARLY EVENING.

CONVECTIVE ACTIVITY MAY CONTINUE OR EVEN INCREASE NORTHEASTWARD
THROUGH OKLAHOMA OVERNIGHT...SUPPORTED BY FORCING ON TAIL END OF
SHORT WAVE TROUGH LIFTING...IN NEGATIVELY TILTED FASHION...INTO THE
HIGH PLAINS.

**FOR MORE SPECIFIC INFORMATION CONCERNING ONGOING OR MORE IMMINENT
CONVECTIVE THREATS...PLEASE REFER TO LATEST SPC MESOSCALE
DISCUSSIONS.

..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.