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 >
Nov 21, 2014 1300 UTC Day 1 Convective Outlook
Updated: Fri Nov 21 12:41:38 UTC 2014 (Print Version | 20141121 1300Z Day 1 shapefile | 20141121 1300Z 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 211241

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0641 AM CST FRI NOV 21 2014

   VALID 211300Z - 221200Z

   ...THERE IS A MRGL RISK OF SVR TSTMS OVER NORTHWEST TX INTO SRN
   OK...

   ...SUMMARY...
   A FEW SEVERE STORMS MAY OCCUR TONIGHT OVER PORTIONS OF NORTHWEST
   TEXAS INTO SOUTHERN OKLAHOMA. LARGE HAIL WILL BE THE PRIMARY HAZARD.

   ...SYNOPSIS...

   THE PRIMARY FEATURE OF INTEREST DURING THE DAY ONE PERIOD IS A
   SRN-BRANCH SHORT-WAVE TROUGH WHICH WILL TRANSLATE FROM SRN CA INTO
   NWRN MEXICO BY 22/12Z. AT THE SURFACE...AN ASSOCIATED AREA OF LOW
   PRESSURE WILL DEVELOP FROM THE LOWER CO VALLEY INTO THE LOWER RIO
   GRANDE VALLEY WHILE A QUASI-STATIONARY FRONT CURRENTLY FROM THE TX
   PERMIAN BASIN INTO OZARK PLATEAU WEAKENS AS IT DEVELOPS NWD AS A
   WARM FRONT.

   ...SRN PLAINS TONIGHT...

   SURFACE OBSERVATIONS AND GPS PW DATA INDICATE THAT CONSIDERABLE
   MOISTENING OF THE AIR MASS HAS OCCURRED OVERNIGHT FROM CNTRL TX NWD
   THROUGH THE RED RIVER VALLEY WITH DEWPOINTS RANGING FROM THE MID 60S
   OVER DEEP SOUTH TX TO THE MID 50S OVER SRN OK AS OF 12Z. SUBSEQUENT
   MOISTURE FLUX WILL BE MOST PROMINENT OVER W-CNTRL TX ALONG A SLY LLJ
   WHICH WILL STRENGTHEN TO 40-45 KT LATER TODAY INTO TONIGHT. THIS
   PROCESS WILL OCCUR BENEATH STEADILY STEEPENING MID-LEVEL LAPSE RATES
   ASSOCIATED WITH AN EML BEING ADVECTED OFF THE PLATEAU REGIONS OF THE
   SWRN U.S. AND NRN MEXICO. THESE DIFFERENTIAL ADVECTIONS WILL YIELD
   MUCAPE APPROACHING 1000-1500 J/KG AFTER DARK FROM PORTIONS OF THE
   LOWER RIO GRANDE VALLEY INTO NWRN TX.

   INITIAL TSTM DEVELOPMENT WILL LIKELY OCCUR TODAY ALONG THE
   WARM-CONVEYOR AIR STREAM FROM PORTIONS OF THE TX COAST INTO THE RED
   RIVER VALLEY AMIDST A WEAK-LAPSE-RATE AND ONLY MARGINALLY UNSTABLE
   ENVIRONMENT. WHILE SOME OF THESE STORMS MAY EXHIBIT EPISODIC UPDRAFT
   ROTATION OWING TO A VERTICALLY VEERING WIND PROFILE WITH 30-35 KT OF
   EFFECTIVE BULK SHEAR...SEVERE WEATHER POTENTIAL SHOULD BE LIMITED BY
   THE POOR LAPSE RATES.

   BY TONIGHT...INCREASING HEIGHT FALLS/DCVA ATTENDANT TO THE MID-LEVEL
   TROUGH WILL COMBINE WITH WAA/ISENTROPIC ASCENT WITHIN THE EXIT
   REGION OF THE LLJ TO FOSTER THE DEVELOPMENT OF MAINLY ELEVATED
   STORMS FROM PORTIONS OF W-CNTRL TX INTO SRN OK. HERE...A FAVORABLE
   OVERLAP OF MODERATE INSTABILITY AND AMPLE CLOUD-BEARING SHEAR MAY
   PROMOTE A FEW SEVERE STORMS CAPABLE OF MARGINALLY SEVERE HAIL.

   ..MEAD/GLEASON.. 11/21/2014

   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z

        
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: November 21, 2014
Disclaimer
Information Quality
Help
Glossary
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities