204  
ACUS03 KWNS 200821  
SWODY3  
SPC AC 200820  
 
DAY 3 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
0220 AM CST MON JAN 20 2020  
 
VALID 221200Z - 231200Z  
   
..NO SEVERE THUNDERSTORM AREAS FORECAST
 
 
   
..SUMMARY
 
 
SHOWERS AND SOME EMBEDDED LIGHTNING SHOULD EVOLVE OVER PORTIONS OF  
EASTERN TEXAS LATE WEDNESDAY/EARLY THURSDAY.  
   
..SYNOPSIS
 
 
AS BOTH NORTHERN- AND SOUTHERN-STREAM UPPER TROUGHING DEPART THE  
EASTERN U.S. EARLY WEDNESDAY, ATTENTION SHIFTS WESTWARD, WHERE A  
DYNAMIC/EVOLVING UPPER FLOW FIELD IS EXPECTED.  
 
INITIALLY, TWO DISTINCT SOUTHERN-STREAM SHORT-WAVE FEATURES ARE  
EXPECTED TO BE CROSSING THE SOUTHWESTERN AND SOUTH-CENTRAL U.S. --  
ONE OVER THE CENTRAL AND SOUTHERN PLAINS, AND THE SECOND CROSSING  
NEW MEXICO/FAR WEST TEXAS/NORTHWESTERN MEXICO. MEANWHILE, A  
SECOND/STRONGER SHORT-WAVE TROUGH IN THE NORTHERN STREAM IS PROGGED  
TO SHIFT OUT OF THE PACIFIC NORTHWEST AND ACROSS THE NORTHERN  
INTERMOUNTAIN REGION DURING THE DAY. WITH TIME, THIS FEATURE IS  
SHOULD BEGIN DIGGING SOUTHEASTWARD TOWARD THE PLAINS, GRADUALLY  
BECOMING PHASED WITH THE SOUTHERN-STREAM ENERGY AND EVENTUALLY  
YIELDING LARGE-SCALE TROUGHING/CYCLONIC FLOW THAT WILL ENCOMPASS A  
LARGE PORTION OF THE COUNTRY.  
 
WITH COLD/STABLE AIR PREVAILING ACROSS THE COUNTRY AT LOW LEVELS,  
SURFACE RESPONSE TO THE EXPANDING UPPER TROUGH WILL MOST LIKELY BE  
REALIZED NEAR THE TEXAS COAST, WHERE A DEFAULT, GULF-INDUCED  
BAROCLINIC ZONE WILL RESIDE. LOW-LEVEL THETA-E ADVECTION ACROSS  
EAST TEXAS IN ADVANCE OF THE UPPER SYSTEM SHOULD PERMIT WEAK  
DESTABILIZATION ABOVE A STILL-STABLE INLAND BOUNDARY LAYER, LIKELY  
SUPPORTING ELEVATED SHOWER/THUNDERSTORM DEVELOPMENT DURING THE LATE  
EVENING/OVERNIGHT PERIOD.  
 
WITH ONLY WEAK ELEVATED CAPE EXPECTED, LITTLE RISK FOR ANY MORE THAN  
SMALL HAIL IS ANTICIPATED INLAND. AT THIS TIME, IT APPEARS THAT THE  
ONLY NON-ZERO SEVERE RISK WHICH COULD EVOLVE, WOULD LIKELY RESIDE  
OVER THE MIDDLE AND UPPER TEXAS COASTAL AREAS. THIS RISK WOULD  
HOWEVER REQUIRE INLAND ADVECTION OF GULF AIR, WHICH REMAINS FAR FROM  
CERTAIN GIVEN REASONABLE LIKELIHOOD THAT SURFACE CYCLOGENESIS  
REMAINS JUST OFFSHORE. EVEN WITH SOME INLAND ADVECTION OF A GULF  
BOUNDARY LAYER HOWEVER, SHEAR APPEARS LIKELY TO REMAIN ON THE  
MARGINAL END OF THE SPECTRUM, WITH RESPECT TO APPRECIABLE  
SURFACE-BASED SEVERE POTENTIAL. AS SUCH, WILL REFRAIN FROM  
INTRODUCING EVEN MARGINAL SEVERE-WEATHER PROBABILITY AT THIS TIME.  
 
..GOSS.. 01/20/2020  
 

 
 
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