871
ACUS48 KWNS 200936
SWOD48
SPC AC 200935
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0335 AM CST TUE NOV 20 2018
VALID 231200Z - 281200Z
..DISCUSSION
MEDIUM-RANGE GUIDANCE HAS COME INTO A LITTLE BETTER AGREEMENT
REGARDING THE EVOLUTION OF THE SHORTWAVE TROUGH EXPECTED TO BE OVER
THE CENTRAL/SOUTHERN PLAINS AT THE BEGINNING OF THE PERIOD (I.E. 12Z
FRIDAY). EXPECTATION IS FOR THE SYSTEM TO MOVE EASTWARD THROUGH THE
MS VALLEY WITH THE STRONG MID-LEVEL FLOW THROUGH ITS BASE SPREADING
ACROSS THE SOUTHEAST. ASSOCIATED WIND PROFILES ACROSS THE SOUTHEAST
ARE FAVORABLE FOR ORGANIZED STORMS BUT THE ATTENDANT SURFACE LOW
EXPECTED TO REMAIN CLOSE TO THE COAST, PREVENTING MUCH INLAND
PENETRATION OF THE WARM SECTOR. ADDITIONALLY, A SMALL SHIFT IN THE
TRACK OF THE OVERALL SYSTEM COULD PLACE THE LOW ENTIRELY OFFSHORE.
FORECAST UNCERTAINTIES ALONG WITH A FAIRLY LIMITED THREAT AREA
PRECLUDE THE NEED TO OUTLOOK ANY AREAS ON D4/FRIDAY.
THE SAME SHORTWAVE TROUGH IS EXPECTED TO CONTINUE
EASTWARD/NORTHEASTWARD WITH SOME RESULTING SEVERE POTENTIAL ON
D5/SATURDAY ACROSS THE CAROLINAS. HOWEVER, LIKE D4/FRIDAY, THE RISK
IS HEAVILY DEPENDENT ON THE TRACK OF THE SURFACE LOW, WHICH HAS
SHOWN TOO MUCH FORECAST VARIABILITY WITHIN THE GUIDANCE FOR MUCH
FORECAST CONFIDENCE.
AFTER D5/SATURDAY, THE PROGRESSIVE UPPER PATTERN IS EXPECTED TO
CONTINUE WITH ANOTHER SHORTWAVE TROUGH MOVING FROM THE PLAINS INTO
THE MS VALLEY ON D6/SUNDAY. STRONG DYNAMICS WILL ACCOMPANY THE
SYSTEM BUT GUIDANCE HAS SHOWN SIGNIFICANT VARIABILITY REGARDING THE
LATITUDE OF THE SYSTEM. A LOWER LATITUDE SYSTEM COULD POSE A SEVERE
RISK AS IT INTERACTS WITH GULF MOISTURE BUT MORE MODEL CONSISTENCY
IS STILL NEEDED TO HAVE ANY CONFIDENCE ON SEVERE POTENTIAL.
..MOSIER.. 11/20/2018
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page