[SWODY2] SWODY2

[SWODY2 at goshenarc.org]

ACUS02 KWNS 211732
SWODY2
SPC AC 211731

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1231 PM CDT THU OCT 21 2004

VALID 221200Z - 231200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM EMP 20
NW FNB 20 WNW OTG 20 ESE ATY 25 NNE AXN 40 S DLH 30 NW OSH CMI ARG
GGG ACT 40 SW BWD ABI OKC EMP.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 65 SE ELP 25 NNE HOB
CSM 15 SW SLN 55 WNW CNK 55 SE GLD 25 ENE LHX 10 E PUB 25 SE ALS 40
NNW 4SL 35 WSW 4BL 20 WSW 4HV 25 W VEL 30 W LAR 55 NW CDR 45 NNE MBG
35 WNW INL ...CONT... 35 ESE OSC 10 NE ARB IND 10 SSW MEM 45 W LFK
30 SSE DRT.

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS A LARGE PORTION OF THE
ERN PLAINS STATES...

...SYNOPSIS...
UPPER TROUGH INITIALLY OVER THE ROCKIES IS FORECAST TO SHIFT ENEWD
ACROSS THE PLAINS STATES THIS PERIOD...ACCOMPANIED BY 70 TO 80 KT
SWLY MID-LEVEL JET.  DOWNSTREAM...HIGHLY-AMPLIFIED RIDGE WILL SHIFT
EWD ACROSS THE LOWER GREAT LAKES / OH AND TN VALLEYS / WRN GULF
THROUGH THE PERIOD.

AT THE SURFACE...LOW INITIALLY FORECAST ACROSS NERN CO WILL DEEPEN
AND SHIFT ENEWD ACROSS NEB DURING THE DAY...AND THEN NEWD ACROSS MN
TOWARD LAKE SUPERIOR LATE IN THE PERIOD.  A NW-SE ORIENTED WARM
FRONT AT THE LEADING EDGE OF RETURNING MOIST LOW-LEVEL AIRMASS IS
FORECAST TO SHIFT SLOWLY NEWD ACROSS THE MID MO / MID MS
VALLEYS...AND WILL LIKELY PROVIDE A ZONE OF FOCUS FOR THUNDERSTORM
DEVELOPMENT.  OTHER LOW-LEVEL FOCUS FOR STORM DEVELOPMENT WILL BE
THE COLD FRONT...FORECAST TO MOVE RAPIDLY EWD / SEWD ACROSS THE
PLAINS DURING THE SECOND HALF OF THE PERIOD.  THIS FRONT -- FORECAST
TO EXTEND FROM MN SWWD INTO FAR NWRN KS DURING THE AFTERNOON --
SHOULD ARC FROM THE WRN UPPER LAKES SWWD ACROSS MO AND INTO THE
TRANSPECOS REGION OF TX BY THE END OF THE PERIOD.

...UPPER MS VALLEY SSWWD INTO PARTS OF OK / TX...
COMPLEX FORECAST THIS PERIOD AS RAPID CHANGES TO THE OVERALL
ENVIRONMENT WILL OCCUR OVER THE NEXT 24 TO 48 HOURS AHEAD OF LARGE
UPPER TROUGH APPROACHING FROM THE WEST.  FORECAST WILL BE FURTHER
COMPLICATED BY UNCERTAINTIES REGARDING LOCATION AND COVERAGE OF
STORMS ASSOCIATED WITH STRONG WARM ADVECTION REGIME DURING THE
MORNING / AFTERNOON...AND WHAT EFFECTS THIS CONVECTION WILL HAVE ON
THE THERMODYNAMIC ENVIRONMENT AS UPPER TROUGH / COLD FRONT APPROACH
LATER IN THE DAY.

ATTM...IT APPEARS THAT ANY ONGOING CONVECTION AT THE START OF THE
PERIOD SHOULD INCREASE THROUGH THE MORNING / AFTERNOON FROM THE
UPPER MS VALLEY SWWD INTO TX.  THOUGH SHEAR BY THIS TIME SHOULD
ALREADY BE SUFFICIENT FOR SEVERE STORMS ACROSS A LARGE AREA...ONE
FOCUSED AREA OF THREAT WILL LIKELY EXIST ALONG RETREATING WARM FRONT
ACROSS PARTS OF IA / MO INTO THE MID MS VALLEY.  WITH BACKED
LOW-LEVEL WIND FIELD ALONG AND ON THE COOL SIDE OF THIS BOUNDARY AND
PARTICULARLY E / NE OF SURFACE LOW...A FAVORABLE ZONE FOR LOW-LEVEL
STORM ROTATION AND THE POSSIBILITY FOR TORNADOES WILL EXIST --
SHIFTING NEWD THROUGH THE END OF THE PERIOD.

MORE UNCERTAIN WILL BE THE EVOLUTION OF ONGOING CONVECTION ACROSS
THE WARM SECTOR.  IT APPEARS THAT STORMS SHOULD BEGIN TO ORGANIZE
LINEARLY LATER IN THE AFTERNOON AND THROUGH THE SECOND HALF OF THE
PERIOD AS UPPER TROUGH APPROACHES AND COLD FRONT BEGINS A STRONGER
PUSH EWD / SEWD.  ALTHOUGH HAIL AND LOCALLY DAMAGING WINDS ALONG
WITH A COUPLE OF TORNADOES WILL PERSIST THROUGH MUCH OF THE DAY FROM
ROUGHLY NERN OK NEWD...THREAT MAY EVOLVE MORE TOWARD DAMAGING WINDS
THROUGH THE EVENING AND OVERNIGHT AS MORE LINEAR ORGANIZATION LIKELY
OCCURS.

FURTHER SWWD ACROSS OK AND INTO PARTS OF TX...STORMS SHOULD BE LESS
WIDESPREAD -- LIKELY INITIATING ALONG AN EWD-MOVING DRYLINE.  THOUGH
SHEAR WILL BE SUFFICIENT FOR SUPERCELLS...A DRIER / MORE
DEEPLY-MIXED BOUNDARY LAYER SUGGESTS THAT HAIL AND LOCALLY DAMAGING
WINDS WILL BE THE PRIMARY SEVERE THREATS -- WITH THREAT DECREASING
WITH SWWD EXTENT.

..GOSS.. 10/21/2004

...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.