[SWODY1] SWODY1

[SWODY1 at goshenarc.org]

ACUS01 KWNS 080512
SWODY1
SPC AC 080510

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1210 AM CDT SUN MAY 08 2005

VALID 081200Z - 091200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 20 N
ELO 55 N EAU OTM 20 E SGF 15 SSW HOT 25 NNE SHV 50 ENE LFK 25 SSE
VCT 40 S LRD ...CONT... 45 ESE P07 50 WSW ABI 45 ENE GAG 30 NNW RSL
40 NE BUB 15 NNW 9V9 40 SE BIS 40 NNW JMS 20 NE RRT.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 10 WSW ANJ 40 NE MKG
25 SSW FWA 35 WNW JKL 15 ENE CSV 25 ENE HSV 35 ESE GWO 25 SW HEZ 7R4
...CONT... 40 SSW P07 55 E AMA 25 N LBL 30 SE TAD 50 ENE DRO 40 NNE
CNY 55 NNW PUC 30 SW ENV 40 WNW ELY 45 NNE TPH 30 NNW BIH 15 ESE FAT
35 W FAT 25 SW SCK 40 WSW SAC 60 NNW UKI ...CONT... 45 NNW FCA 10
NNE HLN 20 SE BZN 25 S COD 35 ESE RWL 20 NNW CYS 50 W CDR 45 ESE 4BQ
10 SSE GDV 75 NE ISN.

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE PLAINS FROM THE ERN
DAKOTAS / WRN MN SWD TO TX...

...SYNOPSIS...
UNUSUAL / HIGHLY-AMPLIFIED FLOW PATTERN FORECAST ACROSS THE CONUS
THIS PERIOD...WITH A DEEP CLOSED LOW APPROACHING THE W COAST...ONE
VACATING THE E COAST...AND A LOW / SHARP TROUGH OVER THE CENTRAL
CONUS. 

GREATEST SEVERE THREAT THIS PERIOD IS FORECAST ACROSS THE
PLAINS...WHERE MODERATELY-UNSTABLE AIRMASS AHEAD SURFACE LOW AND
ASSOCIATED TROUGH / FRONT WILL EXIST.  STRONG RIDGING AT MID LEVELS
-- BOTH UPSTREAM AND DOWNSTREAM -- SHOULD CONFINE CONVECTIVE THREAT
PRIMARILY TO THE PLAINS / MS VALLEY REGION.  FURTHER W...A
CONVECTIVE / LOW-END SEVERE THREAT IS ANTICIPATED ACROSS THE PAC NW
AHEAD OF UPPER LOW APPROACHING THIS REGION.

...CENTRAL QUARTER OF THE CONUS FROM MN / THE ERN DAKOTAS TO TX...
COMPLEX FORECAST THIS PERIOD...AS ONGOING CONVECTION EXPECTED OVER
PORTIONS OF TX -- AS WELL AS STORMS NOW MOVING EWD ACROSS THE NRN
PLAINS -- WILL COMPLICATE THE SCENARIO IN TERMS OF LOCATION AND
SEVERITY OF STORMS THROUGH THE DAY 1 PERIOD.

MODELS DIFFER WITH REGARDS TO LOCATION AND TIMING OF STORMS OVER TX
-- DEVELOPING ATTM IN RESPONSE TO APPROACHING SRN STREAM SHORT-WAVE
TROUGH.  NAM SHOWS THAT LARGE CONVECTIVE CLUSTER WILL EVOLVE EARLY
THIS MORNING...WHICH MOVES INTO ERN / SERN TX BY MIDDAY.  AS A
RESULT...AIRMASS ACROSS CENTRAL TX DESTABILIZES AGAIN AHEAD OF UPPER
FEATURE...ALLOWING A SECOND ROUND OF CONVECTION TO DEVELOP ACROSS
CENTRAL TX.  THOUGH NAMKF IS SOMEWHAT SIMILAR IN OVERALL
SCENARIO...IT MOVES INITIAL CONVECTIVE CLUSTER ACROSS NRN / NERN TX.
 THIS RESULTS IN NEW ROUND OF CONVECTION FORMING DURING THE
AFTERNOON ACROSS CENTRAL TX -- ON SRN PERIPHERY OF INITIAL
CONVECTIVE CLUSTER.  MEANWHILE...GFS DEVELOPS A MUCH LARGER AREA OF
CONVECTION WHICH MOVES SLOWLY EWD ACROSS CENTRAL TX THROUGH THE DAY
-- AS OPPOSED TO THE EPISODIC SCENARIO DEPICTED BY THE TWO NAM RUNS.


OVERALL...UPPER 60S DEWPOINTS SHOULD BE SPREADING INTO CENTRAL TX
BENEATH STEEP MID-LEVEL LAPSE RATES ADVECTING EWD ACROSS THIS
REGION.  THEREFORE -- AREAS AWAY FROM ONGOING CONVECTION / CLOUD
COVER WHICH RECEIVE SUBSTANTIAL DAYTIME HEATING SHOULD BECOME QUITE
UNSTABLE DURING THE AFTERNOON. MODERATELY-STRONG WSWLY MID-LEVEL
WIND MAX MOVING ACROSS CENTRAL / S TX ABOVE SELY BOUNDARY LAYER FLOW
WILL RESULT IN SUFFICIENT SHEAR FOR SUPERCELLS.  THEREFORE...WILL
MAINTAIN MAXIMUM IN SEVERE PROBABILITIES ACROSS CENTRAL TX...THOUGH
DETAILS IN TIMING / LOCATION AS WELL AS INTENSITY OF SEVERE THREAT
WILL OBVIOUSLY DEPEND UPON EVOLUTION OF CONVECTION ONGOING EARLY IN
THE PERIOD.

SEVERE THREAT WILL ALSO EXTEND NWD ACROSS THE SRN PLAINS INTO THE
CENTRAL AND NRN PLAINS / MO VALLEY REGION AHEAD OF SURFACE TROUGH /
BAROCLINIC ZONE AND ASSOCIATED SURFACE LOW WHICH WILL MOVE SLOWLY
EWD WITH TIME. GENERALLY WEAKER / MORE SLY MID-LEVEL FLOW ACROSS
MUCH OF THE REGION SUGGESTS A SOMEWHAT LESSER SEVERE THREAT AS
COMPARED TO TX.  NONETHELESS...EXPECT MODERATE INSTABILITY AND
MARGINAL SHEAR TO SUPPORT ORGANIZED / SUPERCELL STORMS CAPABLE OF
PRODUCING LARGE HAIL AND LOCALLY DAMAGING WINDS.  GREATEST THREAT
SHOULD OCCUR FROM ROUGHLY THE MIDDLE MO VALLEY NWD TOWARD THE RED
RIVER VALLEY...AHEAD OF MAIN UPPER FEATURE.

OVERNIGHT...THREAT SHOULD DIMINISH SLOWLY WITH TIME...THOUGH A
LIMITED SEVERE THREAT MAY EXTEND EWD ACROSS THE MID / UPPER MS
THROUGH THE END OF THE PERIOD.

...PAC NW...
COLD FRONT IS FORECAST TO MOVE ACROSS WA / ORE DURING THE DAY AHEAD
OF CLOSED LOW APPROACHING W COAST.  MARGINAL INSTABILITY FORECAST
ACROSS THIS REGION SHOULD SUPPORT THE DEVELOPMENT OF SCATTERED
THUNDERSTORMS DURING THE AFTERNOON.  DESPITE VEERING WINDS WITH
HEIGHT / SUFFICIENT SHEAR FOR ORGANIZED STORMS...WEAK INSTABILITY
FORECAST SHOULD LIMIT SEVERE THREAT.  THUS...WILL MAINTAIN ONLY 5%
HAIL / WIND PROBABILITIES ACROSS THIS REGION.

..GOSS.. 05/08/2005

...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.