[SWODY1] SWODY1

[SWODY1 at goshenarc.org]

ACUS01 KWNS 211244
SWODY1
SPC AC 211242

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0742 AM CDT THU OCT 21 2004

VALID 211300Z - 221200Z

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 30 SSE LGB 30 SSE DAG
15 W LAS 30 SSE P38 30 NE BCE 55 SE CNY 20 NW ALS 30 SSE ALS 35 NNW
LVS 45 NW TCS 60 SW TUS.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 40 SW GLS 20 NNW HOU
25 N CLL 30 WNW TPL 45 NNE DRT 25 ESE FST HOB 25 NNE GAG 20 WNW OLU
55 NE ATY 40 NE STC 35 N VOK 30 S RFD 15 NE UIN 15 SSE FYV 30 E PGO
40 N ELD 15 S GWO 25 NW TCL 35 SSE HSV 35 NW CHA 30 NNW TYS 20 NW
HSS 10 E AVL 25 S AHN 60 ESE MCN 20 NNE SSI.

...NO SVR TSTM AREAS FORECAST...

...SRN PLAINS...

MARITIME TROPICAL BOUNDARY LAYER AIRMASS CONTINUES ITS NWWD RETURN
ACROSS TX/OK AS UPPER RIDGE AXIS BUILDS SLOWLY EWD ACROSS THE
PLAINS.  THIS RETURN OF MOISTURE WILL PROVE INSTRUMENTAL IN
POTENTIAL CONVECTIVE DEVELOPMENT LATER THIS AFTERNOON ALONG A
SHARPENING DRY LINE FROM PORTIONS OF NWRN TX INTO WRN OK.

EARLY MORNING SATELLITE IMAGERY SUGGEST DAYTIME HEATING AND WEAK
CONVERGENCE ALONG THE DRY LINE WILL PRIMARILY BE RESPONSIBLE FOR
INITIATING TSTM DEVELOPMENT...PARTLY DUE TO THE APPARENT LACK OF ANY
MEANINGFUL UPPER SHORTWAVE TROUGH UPSTREAM OF THIS REGION.  ALTHOUGH
THIS ACTIVITY MAY STRUGGLE THROUGH EARLY EVENING...STRONG DEEP LAYER
SHEAR AND SUFFICIENT INSTABILITY WILL ALLOW ACTIVITY TO PERSIST
UNTIL LLJ INCREASES AFTER DARK.  THIS INCREASE MAY ALLOW FOR STORM
MERGERS AND CLUSTERING THAT SHOULD ALLOW CONVECTION TO SPREAD NEWD
ALONG/EAST OF THE DRY LINE ACROSS NWRN TX/WRN OK INTO SCNTRL KS
DURING THE LATE EVENING HOURS. ISOLATED HAIL OR GUSTY WINDS ARE
POSSIBLE WITH THE STRONGEST STORMS.  SOMEWHAT MARGINAL
INSTABILITY...1000-1500 J/KG SFC-BASED CAPE...MAY ULTIMATELY LIMIT
SEVERE POTENTIAL AND COVERAGE.


...IA...

LLJ IS EXPECTED TO INCREASE LATE TONIGHT ACROSS ERN PORTIONS OF THE
CENTRAL PLAINS.  THIS WILL ALLOW ELEVATED SOURCE OF MOISTURE TO
RETURN ACROSS THE PLAINS INTO THE MID MS VALLEY REGION WHERE SLOW
MOISTENING ABOVE THE BOUNDARY LAYER MAY RESULT IN TSTM DEVELOPMENT
WELL AFTER MIDNIGHT.  FORECAST SOUNDINGS SUGGEST PARCELS LIFTED
AROUND 850MB MAY YIELD CAPE VALUES ON THE ORDER OF 1500-2000 J/KG. 
IF THIS EVOLVES AND THUNDERSTORMS CAN DEVELOP WITHIN INCREASING WARM
ADVECTION REGIME...THERE APPEARS TO BE SOME THREAT FOR LARGE HAIL
WITH TSTM DEVELOPMENT. THERE IS SOME CONCERN SUFFICIENT FORCING MAY
NOT DEVELOP ACROSS THIS REGION UNTIL EARLY IN THE DAY2
PERIOD...SHORTLY AFTER 12Z.  FOR THIS REASON A SLIGHT RISK WILL NOT
BE ISSUED FOR THIS AREA.

..DARROW/BANACOS.. 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.