Issued by NWS
000 ACUS48 KWNS 230946 SWOD48 SPC AC 230946 DAY 4-8 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0346 AM CST MON NOV 23 2009 VALID 261200Z - 011200Z ...DISCUSSION... PROGRESSIVE AND HIGH-AMPLITUDE FLOW REGIME WILL DOMINANT THE MEDIUM RANGE. STRONG UPR TROUGH THAT EVOLVES OVER THE ERN HALF OF THE COUNTRY WEDNESDAY AND THURSDAY WILL QUICKLY DEPART THE ERN SEABOARD BY THE UPCOMING WEEKEND. BUILDING SFC HIGH PRESSURE WILL SEND A CDFNT WELL S INTO THE SRN GULF OF MEXICO LATE IN THE WEEK. NEXT SYSTEM IS FCST TO QUICKLY MOVE INTO THE NRN ROCKIES LATE FRIDAY AND SATURDAY. SPREAD IN MODEL GUIDANCE BEGINS TO INCREASE OVER THE WEEKEND...PRIMARILY IN HOW MUCH SRN STREAM ENERGY CAN BECOME DETACHED FROM THE NRN STREAM UPR LOW. FAMILY OF ECMWF DETERMINISTIC AND MEANS SUGGEST A SLOWER AND LESS AMPLIFIED SOLUTION...WHICH HAS BEEN MORE CONSISTENT OVER THE PAST SVRL RUNS. IT IS REASONABLE TO EXPECT AN INCREASE IN THE RETURN FLOW REGIME AHEAD OF THE TROUGH OVER THE WEEKEND WITH AN INCREASE IN TSTM THREATS OVER PARTS OF THE SRN PLNS EWD ACROSS THE GULF CSTL REGION BY EARLY NEXT WEEK. GULF MOISTURE WILL MOST LIKELY BE OF ONLY MODEST QUALITY AND GIVEN VARIABILITY IN MODELS IN HANDLING OF THE WEEKEND TROUGH...FCST CONFIDENCE IN A SVR EPISODE IS NOT HIGH. ..RACY.. 11/23/2009
