[SWODY1] SWODY1

[SWODY1 at goshenarc.org]

ACUS01 KWNS 131228
SWODY1
SPC AC 131227

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0627 AM CST SUN FEB 13 2005

VALID 131300Z - 141200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 15 SW
PSX 55 SE AUS 40 E TPL 45 N HOT 30 NNE UNO 40 WNW CGI 30 S PAH 40
WSW CBM 30 WSW SEM 15 SSW CEW.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 15 WNW DRT 40 N JCT
30 NNW PRX 25 WSW FYV 35 W JEF 50 SSE P35 15 SSW OTM 15 N BMI 20 ENE
HUF 10 NE BWG 35 ENE HSV 30 S AUO 25 NE AQQ.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 35 SE CRP 60 WNW MFE.

...THERE IS A SLGT RISK OF SVR TSTMS FROM ERN TX ACROSS THE LOWER MS
RIVER VALLEY...

...SYNOPSIS...
SEVERE THUNDERSTORM FORECAST REMAINS COMPLEX THIS MORNING...AS
PRIMARY SHORTWAVE TROUGH NOW ENTERING THE SRN PLAINS PROGRESSES EWD
TOWARDS THE MS RIVER VALLEY IN THE FORM OF TWO OR MORE DISTINCT VORT
MAXIMA.  LEADING SYSTEM NOW EJECTING NEWD ACROSS ERN KS WILL DAMPEN
OUT AS IT LIFTS INTO THE MID MS RIVER VALLEY TODAY...WHILE SECONDARY
SYSTEM STRENGTHENS AS IT MOVES INTO BASE OF TROUGH OVER TX.  SURFACE
LOW OVER KS ATTM WILL LIFT NNEWD INTO NRN IL BY THIS EVENING
/ASSOCIATED WITH EJECTING ENERGY OVER THE CENTRAL PLAINS/ WHILE
TRAILING COLD FRONT MOVES EWD INTO CENTRAL MO/AR/ERN TX THROUGH THE
DAY.  THIS WILL ALLOW A NARROW AXIS OF GULF MOISTURE TO DEVELOP
STEADILY NNEWD ACROSS ERN TX/LA INTO THE LOWER MS RIVER VALLEY/MID
SOUTH...WITH SURFACE DEW POINTS INCREASING INTO THE 50S INTO NRN
AR/SRN MO/FAR WRN TN AND THE LOWER 60S ALONG THE GULF COAST.

...AR/SERN MO/WRN TN...
H5 TEMPS FROM -16C TO -18C AND MODEST HEATING WILL SUPPORT AN AXIS
OF MARGINAL TO MODERATE INSTABILITY AHEAD OF SURFACE COLD FRONT OVER
AR LATER THIS AFTERNOON.  MODIFIED FORECAST SOUNDINGS FROM LATEST
RUC SUGGEST SBCAPE FROM 500-1000 J/KG ARE POSSIBLE AT 21Z...THOUGH
WARM LAYER NEAR H85 MAY PROVE DIFFICULT TO OVERCOME.  GLANCING
INFLUENCE OF STRONGER UVV ASSOCIATED WITH EJECTING SYSTEM SHOULD
ALLOW AT LEAST ISOLATED THUNDERSTORMS TO FORM WITHIN THIS
INSTABILITY AXIS BY LATE IN THE DAY AS COLD FRONT SHIFTS EAST.
EXTREME SHEAR WITH SRH AOA 250 M2/S2 IN THE LOWER KM/S SUGGESTS
SUSTAINED UPDRAFTS WILL BE CAPABLE OF BECOMING QUITE ORGANIZED AND
SHOULD CARRY WITH IT A THREAT OF DAMAGING WINDS/TORNADOES/LARGE HAIL
INTO THE MS RIVER DELTA REGION LATER TODAY. EXTENT OF ANY SUBSEQUENT
SEVERE THREAT EAST OF THE MS RIVER WILL BE LIMITED BY WEAKENING
INSTABILITY AFTER DARK...SUGGESTING SEVERE THREAT ACROSS THIS REGION
MAY HAVE A NARROW WINDOW IN BOTH SPACE AND TIME LATER TODAY.

...ERN TX INTO THE CENTRAL GULF COAST...
SEVERE THREAT MAY GRADUALLY INCREASE ACROSS ERN TX THROUGH THE DAY
AS NEXT SYSTEM DIGS ESEWD INTO BASE OF SHORTWAVE TROUGH.  AIR MASS
CONTINUES TO RECOVER OVER THE WESTERN GULF BASIN WITH SURFACE DEW
POINTS IN THE LOWER 60S NOW IN PLACE ACROSS THE TX COASTAL PLAINS. 
EXPECT PERSISTENT MOISTENING OF THE BOUNDARY LAYER WILL CONTINUE EWD
ACROSS THE LOWER MS RIVER VALLEY THROUGH THE DAY. AS COLD AIR ALOFT
OVERSPREADS THE REGION /H5 TEMPS FROM -16C TO -18C/...LAPSE RATES
WILL STEEPEN AND INCREASE INSTABILITY. THUS...INITIAL STORMS
INCREASING OVER CENTRAL TX EARLY THIS MORNING MAY PRODUCE MARGINALLY
SEVERE HAIL AS THEY SPREAD NEWD.  IN ADDITION...PLUME OF CONVECTION
NOW OVER SERN TX/SWRN TX WILL LIKELY SPREAD ENEWD ACROSS THE LOWER
MS RIVER VALLEY THROUGH THE DAY.  THOUGH INSTABILITY IS NOT EXPECTED
TO SUPPORT SURFACE-BASED DEVELOPMENT WITH THIS ACTIVITY EARLY IN THE
DAY...SHEAR WILL REMAIN STRONG OVER THE ENTIRE REGION AND THUS
INSTABILITY TRENDS WILL NEED TO BE CLOSELY WATCHED.

INCREASING LARGE SCALE ASCENT AND APPROACHING COLD FRONT WILL
INCREASE THE POTENTIAL FOR SURFACE-BASED CONVECTION THIS AFTERNOON
AND EVENING...AS MODIFIED 09Z RUC FORECAST SOUNDINGS INDICATE
MLCAPES NEAR 1000 J/KG ACROSS ERN TX BY 21Z.  STORMS MAY FORM AHEAD
OF APPROACHING COLD FRONT...OR INCREASE WITHIN TRAILING PORTION OF
BAND OF CONVECTION NOW LIFTING NEWD ACROSS SERN TX/SWRN LA AS
SURFACE-BASED CIN DIMINISHES.  THOUGH SSWLY LOW LEVEL WIND FIELDS
WILL LIMIT SHEAR...LENGTH OF SHEAR VECTORS REMAIN MORE THAN
SUPPORTIVE FOR SUPERCELLS/BOW ECHOES SHOULD STORMS ROOT INTO THE
BOUNDARY LAYER.  THIS ACTIVITY WILL LIKELY SHIFT EWD AND MAINTAIN A
SEVERE THREAT OVERNIGHT IN THE FORM OF DAMAGING WINDS/TORNADOES AS
STRONG SHORTWAVE TROUGH AIDS CONVECTION ACROSS THE LOWER MS RIVER
VALLEY.

..EVANS.. 02/13/2005

...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.