[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 041959
SWODY1
SPC AC 041958

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0258 PM CDT THU MAY 04 2006

VALID 042000Z - 051200Z

...THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON AND TONIGHT OVER
PARTS OF W-CNTRL AND CNTRL TX...

...THERE IS A SLGT RISK OF SVR TSTMS FROM ERN NM TO THE SE TX
COAST...

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE ARKLATEX ACROSS NRN
MS...

...ERN NM INTO CNTRL TX...

18Z MESOANALYSIS INDICATES PRESSURE FALLS IN POST-FRONTAL AIR MASS
OVER THE TX PNHDL...SUGGESTING THAT FRONT SHOULD DECELERATE THIS
AFTERNOON...BECOMING QUASI-STATIONARY FROM SERN NM INTO CNTRL TX. 
STRONG DAYTIME HEATING COUPLED WITH STEEP LAPSE RATES AND MODEST
BOUNDARY-LAYER MOISTURE WILL CONTINUE TO SUPPORT FURTHER
DESTABILIZATION INVOF OF THIS BOUNDARY THIS AFTERNOON WITH MLCAPES
INCREASING FROM 1000-1500 J/KG OVER SERN NM INTO WRN TX...TO
2000-3000 J/KG INTO CNTRL TX.  18Z MAF SOUNDING INDICATES THAT WIND
FIELDS HAVE INCREASED ABOVE 4 KM AGL WITH SUFFICIENT VERTICAL SHEAR
/I.E. 30-40 KTS/ PRESENT TO SUPPORT SUPERCELL DEVELOPMENT.

VISIBLE SATELLITE AND LATEST RUC GUIDANCE SUGGEST THAT TSTMS WILL
DEVELOP BY MID TO LATE AFTERNOON ALONG BOTH: 1) THE IMMEDIATE HIGHER
TERRAIN OF CNTRL NM...AND 2) ALONG FRONTAL ZONE ESEWD INTO CNTRL TX
WITH STORMS EVENTUALLY MERGING INTO CLUSTERS OR A MCS TONIGHT AND
MOVING SEWD THROUGH THE HILL COUNTRY INTO PARTS OF ERN/SERN TX. 
INITIAL SUPERCELL MODES WILL BE CAPABLE OF LARGE HAIL /SOME
SIGNIFICANT/ AND PERHAPS A COUPLE TORNADOES...PRIOR TO EVOLVING INTO
MORE OF AN OUTFLOW-DOMINANT CONVECTIVE COMPLEX WITH A THREAT OF HAIL
AND HIGH WINDS.

...ARKALTEX INTO NRN MS...

WELL-DEFINED MCV CONTINUES TO TRANSLATE EWD THIS AFTERNOON OVER SWRN
AR WITH DEQUEEN AR PROFILER INDICATING AN ASSOCIATED NARROW CHANNEL
OF 50 KT WLY FLOW AT 6 KM AGL AROUND THE SRN PERIPHERY OF THIS
FEATURE.  LOW-LEVEL AIR MASS ACROSS NRN LA/SRN AR IS MOIST WITH
DEWPOINTS IN THE MID 60S...WHICH ARE CONTRIBUTING TO MODERATE
INSTABILITY WITH MLCAPES OF 1000-2000 J/KG.  GIVEN THIS MODERATE
INSTABILITY AND MESOSCALE ZONE OF MODERATELY STRONG VERTICAL
SHEAR...EXPECT THE THREAT OF ORGANIZED SEVERE STORMS INCLUDING
SUPERCELLS TO CONTINUE EWD ALONG W-E FRONTAL BOUNDARY INTO THE MS
DELTA THIS AFTERNOON INTO TONIGHT.  LARGE HAIL AND LOCALLY DAMAGING
WINDS APPEAR TO BE THE PRIMARY SEVERE WEATHER THREATS WITH THE MOST
INTENSE STORMS.

...SERN TX INTO SRN LA...

TSTMS HAVE INTENSIFIED THIS AFTERNOON ACROSS REGION AHEAD OF
SECONDARY...WEAKER MCV MOVING MORE SEWD OUT OF THE HILL COUNTRY. 
AMBIENT AIR MASS REMAINS QUITE MOIST WITH DEWPOINTS OF 65-70 F WHICH
ARE LARGELY CONTRIBUTING TO MLCAPES OF 1000-2000 J/KG. 
MOREOVER...HOUSTON VWP INDICATES RELATIVELY STRONG VEERING WITH
HEIGHT WITH 40-45 KTS OF DEEP-LAYER SHEAR.  STORMS NEAR CLL HAVE
RECENTLY STRENGTHENED...AND GIVEN AMBIENT ENVIRONMENT...FURTHER
INTENSIFICATION IS LIKELY THIS AFTERNOON INTO EVENING AS STORMS MOVE
SEWD TOWARD THE COAST. LARGE HAIL AND DAMAGING WINDS WILL BE THE
PRIMARY SEVERE WEATHER HAZARDS.

...TN VALLEY SWD INTO NRN PORTIONS OF AL AND GA...

REGIONAL RADAR IMAGERY INDICATE TSTMS BECOMING INCREASINGLY NUMEROUS
THIS AFTERNOON FROM NEAR CBM EWD ACROSS PARTS OF NRN AL/GA TO NEAR
AHN.  VISIBLE SATELLITE AND MESOANALYSIS SUGGEST THAT THIS ACTIVITY
IS DEVELOPING ALONG AN OUTFLOW BOUNDARY REMNANT FROM EARLIER
CONVECTION.  WHILE AMBIENT AIR MASS IS MOIST AND MODERATELY
UNSTABLE.../MLCAPES OF 1000-1500 J/KG/ AREA VWPS AND RUC OBJECTIVE
FIELDS INDICATE THAT VERTICAL SHEAR AND MID-LEVEL LAPSE RATES REMAIN
QUITE MARGINAL FOR ORGANIZED...SEVERE STORMS.  THUS...CATEGORICAL
SLIGHT RISK HAS BEEN REMOVED.  NONETHELESS...POTENTIAL WILL EXIST
FOR ISOLATED WIND OR HAIL WITH THE MOST INTENSE STORMS INTO THIS
EVENING.

...UPPER OH VALLEY INTO WRN/CNTRL PA AND NY...

DIABATIC HEATING ALONG WITH SOME INCREASE IN LOW-LEVEL MOISTURE FROM
THE SW HAVE RESULTED IN WEAK AIR MASS DESTABILIZATION AHEAD OF
SURFACE FRONT THIS AFTERNOON.  THUS FAR...MOST INTENSE DEEP
CONVECTION HAS REMAINED N OF INTERNATIONAL BORDER OVER FAR SERN
ONTARIO IN ASSOCIATION WITH SRN FRINGE OF STRONGER HEIGHT FALLS
AHEAD OF UPPER LOW OVER ERN ONTARIO.  THIS ACTIVITY MAY MOVE INTO
PARTS OF NRN NY LATE THIS AFTERNOON OR EARLY THIS EVENING WITH
ADDITIONAL STORM DEVELOPMENT POSSIBLE ALONG COLD FRONT INTO ERN OH
OR WRN PA.  STEEP LOW-LEVEL LAPSE RATES AND MODEST UNIDIRECTIONAL
VERTICAL SHEAR MAY SUPPORT A COUPLE STRONG STORMS CAPABLE OF LOCALLY
STRONG WIND GUSTS AND SOME HAIL.

...INTERMOUNTAIN W...

STEEP LOW TO MID-LEVEL LAPSE RATES HAVE CONTRIBUTED TO A WEAKLY
UNSTABLE ENVIRONMENT THIS AFTERNOON AHEAD OF MID-LEVEL TROUGH SLOWLY
TRANSLATING EWD TOWARD THE LOWER CO VALLEY.  THESE STEEP LAPSE RATES
COUPLED WITH A WELL-MIXED BOUNDARY-LAYER WILL SUPPORT ISOLATED
WIND/HAIL WITH THE MOST INTENSE STORMS.

..MEAD.. 05/04/2006