Skip Navigation Links weather.gov 
NOAA logo-Select to go to the NOAA homepage NOAA's National Weather Service   Select to go to the NWS homepage
Storm Prediction Center
navigation bar left  
  navigation bar end cap


 
USA.gov is the U.S. Government's official Web portal to all Federal, state and local government Web resources and services.

    Day 2 Outlook >
Apr 18, 2015 2000 UTC Day 1 Convective Outlook
Click to see valid 1Z - 12Z Day 1 Convective Outlook
Updated: Sat Apr 18 19:49:00 UTC 2015 (Print Version | 20150418 2000Z Day 1 shapefile | 20150418 2000Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Tornado Wind Hail
 Population  Cities/Towns  CWAs  Interstates  Counties  ARTCC  FEMA Regions

 Forecast Discussion
   SPC AC 181949

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0249 PM CDT SAT APR 18 2015

   VALID 182000Z - 191200Z

   ...THERE IS AN ENH RISK OF SVR TSTMS FROM PARTS OF WRN AND CENTRAL
   KS SWD ACROSS CENTRAL TX TO THE RIO GRANDE...

   ...THERE IS A SLGT RISK OF SVR TSTMS FROM NERN CO/SRN NEB SWD ACROSS
   CENTRAL AND S TX...

   ...THERE IS A MRGL RISK OF SVR TSTMS SURROUNDING THE SLIGHT RISK
   AREA...AND ALSO EXTENDING EWD ACROSS THE GULF COAST STATES...

   ...SUMMARY...
   SCATTERED THUNDERSTORMS WILL CONTINUE THIS AFTERNOON AND EVENING
   FROM THE CENTRAL PLAINS TO SOUTH TEXAS...SOME OF WHICH WILL PRODUCE
   HAIL AND SEVERE WIND GUSTS.  A FEW TORNADOES CANNOT BE RULED
   OUT...PARTICULARLY ACROSS THE NORTHERN HALF OF THIS AREA.

   ...DISCUSSION...
   GENERAL FORECAST REASONING AND AREAS REMAIN VALID THIS UPDATE...WITH
   THE MAJOR ADJUSTMENT BEING MADE ATTM TO EXTEND HIGHER /5%/ TORNADO
   PROBABILITY SWD ACROSS THE WRN OK VICINITY.  HERE...LOW-LEVEL FLOW
   CONTINUES TO BACK AHEAD OF THE SURFACE DRYLINE...RESULTING IN SOME
   ENHANCEMENT TO THE LOW-LEVEL SHEAR AS COMPARED TO EARLIER IN THE
   DAY.  AS SUCH...RISK FOR TORNADOES HAS LIKELY BECOME SLIGHTLY
   ENHANCED OVER THIS AREA.  ELSEWHERE...STORMS CONTINUE TO INCREASE
   FROM ERN CO/WRN KS SWD ACROSS WRN OK TO THE TX BIG BEND
   REGION...ALONG THE PRIMARY AXIS OF FORECAST SEVERE RISK.

   ..GOSS.. 04/18/2015

   .PREV DISCUSSION... /ISSUED 1123 AM CDT SAT APR 18 2015/

   ..CENTRAL/SOUTHERN PLAINS...
   MORNING WATER VAPOR LOOPS SHOW A PERSISTENT UPPER LOW OVER CO...WITH
   SEVERAL SHORTWAVE TROUGHS ROTATING THROUGH THE BASE OF THE LOW INTO
   THE SOUTHERN PLAINS.  ONE SUCH FEATURE IS EVIDENT OVER SOUTHEAST
   NM...WHICH WILL TRACK INTO WEST TX AND EVENTUALLY INTO WESTERN OK
   LATER TODAY/TONIGHT.  VISIBLE SATELLITE IMAGERY SHOWS POCKETS OF LOW
   CLOUDS ALONG THE DRYLINE FROM WESTERN KS INTO WEST-CENTRAL TX...BUT
   THOSE CLOUDS WILL LIKELY ERODE BY EARLY AFTERNOON ALLOWING STRONG
   HEATING TO TAKE PLACE.  DEWPOINTS IN THE 60S AND COOL TEMPERATURES
   ALOFT /-16 AND COLDER AT 500MB/ WILL HELP CONTRIBUTE TO AFTERNOON
   MLCAPE VALUES OF 1500+ J/KG AND ONLY A WEAK CAP.  

   SCATTERED THUNDERSTORMS ARE EXPECTED TO FORM ALONG THE ENTIRE LENGTH
   OF THE DRYLINE FROM WESTERN KS INTO WEST TX. SUFFICIENT DEEP-LAYER
   EFFECTIVE SHEAR WILL SUPPORT SUPERCELL STORM STRUCTURES CAPABLE OF
   LARGE HAIL AND PERHAPS DAMAGING WINDS.  ISOLATED TORNADOES ARE ALSO
   POSSIBLE...BUT WEAK LOW LEVEL VERTICAL SHEAR WILL BE A LIMITING
   FACTOR.  THE AREA OF PERHAPS GREATEST TORNADO THREAT WOULD BE OVER
   WESTERN KS INTO WESTERN NEB WHERE EASTERLY NEAR-SURFACE WINDS WILL
   ENHANCE SHEAR.  STORMS THROUGHOUT THE RISK AREA SHOULD PERSIST INTO
   MID-EVENING BEFORE SLOWLY WEAKENING.

   ...GULF COAST STATES...
   A LARGE MCS REMAINS OFF THE COAST OF LA/MS TODAY...LIMITING INFLOW
   INLAND AND MAINTAINING WIDESPREAD CLOUD COVER OVER THE GULF COAST
   STATES.  SLOW/PARTIAL CLEARING IS EXPECTED THROUGH THE AFTERNOON
   OVER PARTS OF LA/MS...WHERE DEWPOINTS ARE IN THE UPPER 60S.  THIS
   MAY LEAD TO POCKETS OF MLCAPE OF 1000 J/KG.  FORECAST SOUNDINGS IN
   THIS REGION ARE MOIST WITH RATHER WEAK MID LEVEL LAPSE RATES AND
   DISORGANIZED LOW LEVEL WINDS.  FOR THIS REASON...WILL MAINTAIN ONLY
   MARGINAL SEVERE PROBABILITIES ACROSS THE REGION.  IF STRONGER
   DESTABILIZATION CAN OCCUR THAN CURRENTLY ANTICIPATED...PORTIONS OF
   THE AREA MAY NEED TO BE UPGRADED TO SLIGHT RISK.

   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z

        
Top/Latest Day 2 Outlook/Today's Outlooks/Forecast Products/Home
Weather Topics:
Watches, Mesoscale Discussions, Outlooks, Fire Weather, All Products, Contact Us

NOAA / National Weather Service
National Centers for Environmental Prediction
Storm Prediction Center
120 David L. Boren Blvd.
Norman, OK 73072 U.S.A.
spc.feedback@noaa.gov
Page last modified: April 18, 2015
Disclaimer
Information Quality
Help
Glossary
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities