ZCZC SPCSWODY1 ALL ACUS01 KWNS 110547 SPC AC 110547 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1147 PM CST MON NOV 10 2003 VALID 111200Z - 121200Z GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 20 NE JMS 35 N PIR 15 S RAP 45 SW GCC 10 NNE HLN 20 WNW GTF 40 ENE OLF 30 ESE MOT 20 NE JMS. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 10 SSE VBG 20 SSW BFL 20 SE DAG 30 NNW BLH 30 SE YUM. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 40 W END 40 N JLN 20 W GRR 35 NE CLE 15 ENE MGW 30 E EKN TRI 10 SE CSV 40 S JBR 30 S MLC 25 N SPS 20 NNW LTS 40 W END. ...NO SVR TSTM AREAS FORECAST... ...SYNOPSIS... AXIS OF STRONG MID- AND UPPER-TROPOSPHERIC FLOW WILL PERSIST FROM THE DESERT SW NEWD ACROSS THE OH VALLEY ON TUESDAY...BETWEEN TROUGHING OVER S-CNTRL CANADA/N-CNTRL U.S. AND RIDGING OVER THE GULF OF MEXICO. POTENT SHORTWAVE TROUGH AND ASSOCIATED UPPER-LEVEL JET STREAK /CURRENTLY ANALYZED OVER BRITISH COLUMBIA/ WILL TRANSLATE SEWD THROUGH THE FORECAST PERIOD...EFFECTIVELY AMPLIFYING THE LARGE-SCALE TROUGH OVER THE NRN PLAINS/GREAT LAKES. IN THE LOW-LEVELS...WEAK SURFACE FRONTAL SYSTEM CURRENTLY FROM THE UPPER MS VALLEY SWWD INTO THE SRN HIGH PLAINS...WILL PROGRESS EWD TODAY AND SHOULD EXTEND FROM THE CNTRL GREAT LAKES SWWD THROUGH THE MID MS VALLEY INTO THE SRN PLAINS BY LATE AFTERNOON. ...OH VALLEY SWWD INTO MIDDLE MS VALLEY... LATEST MESOANALYSIS AND 00Z UPPER-AIR OBSERVATIONS INDICATE THAT LOW-LEVEL MOISTURE RETURN IS UNDERWAY FROM THE WRN GULF OF MEXICO NEWD INTO THE LOWER OH VALLEY. SUSTAINED 35-45KT SWLY LLJ ACROSS THIS SAME GENERAL AREA SHOULD ALLOW NEAR 60F DEWPOINTS TO BE ADVECTED AS FAR NE AS WRN KY AND SRN PARTS OF IL AND IND BY EARLY EVENING. PRIMARY FACTOR LIMITING OVERALL AIRMASS DESTABILIZATION APPEARS TO BE POOR MID-LEVEL LAPSE RATES WHICH WILL BE PRESENT ABOVE THE RETURNING MOISTURE. THE EXCEPTION WILL BE OVER THE SRN PLAINS WHERE 00Z SOUNDINGS INDICATED THE PRESENCE OF A ELEVATED MIXED LAYER AIRMASS AND SUBSEQUENTLY STEEPER LAPSE RATES. CURRENT THINKING IS THAT LOW-LEVEL WARM ADVECTION COUPLED WITH HEIGHT FALLS AHEAD OF AMPLIFYING UPSTREAM TROUGH WILL CONTRIBUTE TO THE DEVELOPMENT OF DEEP CONVECTION BY LATE AFTERNOON/EARLY EVENING ALONG NRN EDGE OF DEEPER LOW-LEVEL MOISTURE /DIFFUSE WARM FRONT/ NEAR THE OH RIVER. ETA FORECAST SOUNDINGS INDICATE STRONG...LARGELY UNIDIRECTIONAL WIND PROFILES OVER THIS AREA WITH 50-60KTS OF SHEAR THROUGH THE LOWEST 6KM. HOWEVER...CONCERN IS WHETHER SHEAR WILL OVERWHELM DEVELOPING UPDRAFTS GIVEN THE WEAK INSTABILITY FORECAST. IF STORMS CAN BECOME SUSTAINED...THE DEGREE OF SHEAR SUGGESTS THE POTENTIAL FOR SUPERCELLS AND/OR BOWING STRUCTURES. THERMODYNAMIC CONDITIONS WILL BE MONITORED AND AN UPGRADE TO SLIGHT RISK MAY BE REQUIRED LATER TODAY IF IT APPEARS MORE INSTABILITY WILL DEVELOP. FARTHER N OVER SRN MI...FORECAST SOUNDINGS INDICATE THE POTENTIAL FOR ELEVATED TSTMS AHEAD OF WEAK SURFACE FRONT...PRIMARILY AFTER 12/00Z. IF STORMS CAN DEVELOP...STEEPER MID-LEVEL LAPSE RATES /7-8 C/KM/ AND LOW WBZ SUGGEST THE POTENTIAL FOR ISOLATED HAIL WITH THE MOST INTENSE CELLS. ADDITIONAL TSTMS WILL LIKELY BUILD SWWD OVERNIGHT INTO PORTIONS OF SRN MO/NRN AR AND POSSIBLY OK ALONG INTENSIFYING SWLY LLJ AXIS WHERE S-R INFLOW WILL BE MAXIMIZED. HERE...STORMS MAY TEND TO BE MORE ELEVATED OR EVEN SUPPRESSED WITH SWRN EXTENT GIVEN STRONGER CAP WHICH IS FORECAST OVER THE SRN PLAINS. ..MEAD/CROSBIE.. 11/11/2003 ...NOTICE... FOR USERS DECODING THE POINTS PARAGRAPH HEREIN...LATITUDE AND LONGITUDE POINTS FOR THE CATEGORICAL AND PROBABILISTIC OUTLOOK GRAPHICS ALSO ARE LOCATED IN A SEPARATE PRODUCT UNDER THE WMO HEADINGS WUUS01 PTSDY1...WUUS02 PTSDY2...AND WUUS03 PTSDY3. THE INCLUSION OF POINTS IN THIS PRODUCT WILL EVENTUALLY BE DISCONTINUED. $$ |