Apr 6, 2014 2000 UTC Day 1 Convective Outlook
Updated: Sun Apr 6 19:59:35 UTC 2014 (20140406 2000Z Day 1 shapefile | 20140406 2000Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20140406 2000 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20140406 2000 UTC Day 1 Tornado Probabilities Graphic
Probability of a tornado within 25 miles of a point.
Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Probabilistic Damaging Wind Graphic
20140406 2000 UTC Day 1 Damaging Wind Probabilities Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Probabilistic Large Hail Graphic
20140406 2000 UTC Day 1 Large Hail Probabilities Graphic
Probability of hail 1" or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 150,354 11,848,777 New Orleans, LA...Birmingham, AL...Baton Rouge, LA...Montgomery, AL...Shreveport, LA...
   SPC AC 061956

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0256 PM CDT SUN APR 06 2014

   VALID 062000Z - 071200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS ERN TX...LA...MS
   AND AL...

   THE ONLY CHANGE TO THE OUTLOOK IS TO REMOVE THE SLIGHT RISK AREA
   FROM PARTS OF CNTRL AND EAST TX. THUNDERSTORMS HAVE MARKEDLY
   DECREASED IN COVERAGE TO THE WEST OF A LINE FROM JUST WEST OF
   HOUSTON EXTENDING NWD TO TYLER. THIS AREA IS BEING IMPACTED BY
   SUBSIDENCE IN THE WAKE OF A VORTICITY MAX OVER THE ARKLATEX AND WILL
   BE AFFECTED BY DRIER AIR ADVECTING IN FROM THE NORTHWEST THIS
   AFTERNOON.

   TO THE EAST ACROSS LA...MS AND AL...A SEVERE THREAT WILL CONTINUE
   FROM THIS AFTERNOON INTO THE OVERNIGHT PERIOD AS A WELL-DEFINED 70
   TO 90 KT MID-LEVEL JET MOVES INTO THE REGION FROM THE SOUTHWEST.
   THIS FEATURE WILL CREATE STRONG DEEP LAYER SHEAR PROFILES OVER THE
   TOP OF A MOIST AIRMASS CREATING CONDITIONS FAVORABLE FOR ROTATING
   STORMS.

   ..BROYLES.. 04/06/2014

   .PREV DISCUSSION... /ISSUED 1128 AM CDT SUN APR 06 2014/

   ...SYNOPSIS...

   THE PRIMARY FEATURE OF INTEREST DURING THE DAY ONE PERIOD IS A
   SRN-STREAM SHORT-WAVE TROUGH OVER THE SRN PLAINS INTO NWRN MEXICO
   WHICH WILL SHIFT EWD INTO THE SRN PLAINS AND LOWER MS VALLEY. AN
   ASSOCIATED 500-MB JET STREAK WILL STRENGTHEN TO 90-100 KT AS IT
   EMERGES FROM THE BASE OF THE PARENT TROUGH BEFORE MOVING INTO THE
   LOWER MS VALLEY TONIGHT IN TANDEM WITH A LEAD VORTICITY MAXIMUM. IN
   RESPONSE TO THE PROGRESSION OF THIS UPPER-AIR SYSTEM...A SSWLY LLJ
   WILL BROADEN AND INTENSIFY TO 50+ KT WHILE MIGRATING FROM THE WRN
   GULF OF MEXICO THROUGH THE LOWER MS AND TN VALLEYS INTO THE
   CNTRL/SRN APPALACHIANS BY 07/12Z.

   AT THE SURFACE...LOW PRESSURE OVER THE LOWER TX COAST WILL DEEPEN
   WHILE DEVELOPING NEWD INTO WRN PARTS OF KY/TN BY DAYBREAK MONDAY. AN
   ASSOCIATED WARM FRONT WILL LIFT NWD THROUGH MS AND AL INTO TN WITH
   THE ERN EXTENSION OF THIS BOUNDARY SHIFTING MORE SLOWLY NWD THROUGH
   PARTS OF GA AND SC. MEANWHILE...A COLD FRONT WILL STRENGTHEN WHILE
   ADVANCING EWD/SEWD INTO THE LOWER MS VALLEY.

   ...CNTRL/ERN TX INTO THE CNTRL GULF COAST STATES THIS AFTERNOON
   THROUGH TONIGHT...

   A CORRIDOR OF ELEVATED TSTMS ARE ONGOING AS OF MID MORNING FROM
   PORTIONS OF N-CNTRL/CNTRL TX INTO CNTRL MS WITH THIS ACTIVITY
   LARGELY BEING FORCED BY WARM AND MOISTURE ADVECTION OCCURRING AT THE
   TERMINUS OF THE LLJ ABOVE THE SURFACE WARM FRONT. THIS REGIME IS
   EXPECTED TO PERSIST TODAY WHILE GRADUALLY SHIFTING EWD/NEWD INTO THE
   LOWER MS VALLEY WITH MARGINALLY SEVERE HAIL BEING THE PRIMARY SEVERE
   WEATHER THREAT.

   THE INLAND DEVELOPMENT AND INTENSIFICATION OF THE LLJ WILL PROMOTE
   THE POLEWARD FLUX OF A SEASONABLY MOIST AIR MASS /I.E. PW VALUES OF
   1.50-1.75 INCHES/ ALONG AND SOUTH OF THE WARM FRONT AND MIGRATORY
   SURFACE LOW WITH MLCAPE INCREASING TO 500-1000 J/KG WITHIN THE
   EXPANDING WARM SECTOR.

   INCREASING HEIGHT FALLS/DCVA AHEAD OF THE MIDLEVEL TROUGH COUPLED
   WITH LOW-LEVEL CONVERGENCE/UPLIFT INVOF SURFACE LOW AND ASSOCIATED
   WARM/COLD FRONTS WILL FOSTER INITIAL SURFACE-BASED STORM DEVELOPMENT
   BY MID TO LATE AFTERNOON OVER PARTS OF SERN TX INTO SRN LA WITH THIS
   ACTIVITY MOVING/DEVELOPING EWD/NEWD THROUGH A LARGE PART OF MS...AL
   AND THE WRN FL PNHDL THIS EVENING THROUGH THE OVERNIGHT HOURS. 

   THE COLOCATION OF THE ABOVE-MENTIONED LOW AND MIDLEVEL WIND MAXIMA
   WILL RESULT IN STRONG LOW-LEVEL AND DEEP-LAYER SHEAR...PARTICULARLY
   FROM SERN LA THROUGH MS/AL DURING THE LATTER HALF OF THE FORECAST
   PERIOD. WHEN COUPLED WITH THE MOIST/LOW LCL BOUNDARY LAYER AND AT
   LEAST MODEST INSTABILITY...THE SETUP WILL BE SUPPORTIVE OF
   SUPERCELLS AND BOWING STRUCTURES CAPABLE OF TORNADOES /SOME POSSIBLY
   EF-2+/ AND WIND DAMAGE...NAMELY ALONG AND SOUTH OF THE I-20
   CORRIDOR.

   ...W-CNTRL TX THIS AFTERNOON INTO EVENING...

   DAYTIME HEATING ALONG THE WRN EDGE OF PERSISTENT LOW CLOUDS COUPLED
   WITH COOLING MIDLEVEL TEMPERATURES WILL YIELD STEEPENING LAPSE RATES
   AND THE DEVELOPMENT OF WEAK INSTABILITY BY AFTERNOON ALONG AND AHEAD
   OF A TROUGH/WEAK FRONT MOVING THROUGH WRN TX. ISOLATED TO WIDELY
   SCATTERED TSTMS ARE LIKELY TO DEVELOP ALONG THIS BOUNDARY BY MID TO
   LATE AFTERNOON WITH THE STEEP LAPSE RATES AND COOL MID-TROPOSPHERIC
   TEMPERATURE PROFILES SUPPORTIVE OF SMALL HAIL AND LOCALLY GUSTY
   WINDS INTO THIS EVENING.

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