Sep 15, 2005 1630 UTC Day 1 Convective Outlook Updated: Thu Sep 15 17:35:58 UTC 2005
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SPC AC 151602 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK ISSUED BY AFWA OFFUTT AIR FORCE BASE BELLEVUE NE 1102 AM CDT THU SEP 15 2005 VALID 151630Z - 161200Z THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 30 SSW ADM 10 NNE PGO 15 NNE JBR 35 W HOP 55 ESE BWG 20 WNW RMG 40 W JAN 55 S SHV 35 SSE TPL 20 SE JCT 50 WSW SJT 25 NNE BGS 30 SSW ADM. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 15 SSE P07 40 SSW MAF 15 W CNM 30 N ROW 25 SSE CVS 55 ESE LBB 20 W FSI 20 SSW TUL 20 NNE SGF 10 NNW SPI 15 ENE AZO 65 SE OSC ...CONT... 25 SSW ILM 15 ESE RDU 20 SE DAN 35 SSW PSK 20 ENE HSS 30 SW AHN 30 SSW CSG 60 SSW SEM 10 WNW MCB 30 WSW 7R4 ...CONT... 30 SW PSX 50 NW LRD. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM MQT AUW MCW SPW 20 SW FSD 35 WNW HON 55 S Y22 15 ESE BZN 45 N FCA. ...THERE IS A SLGT RISK OF SVR TSTMS PARTS OF TX INTO LOWER MS/TN VALLEY... ...SYNOPSIS... THE SRN BRANCH OF AN ACTIVE TWO-STREAM FLOW PATTERN WILL REMAIN THE MAIN PLAYER IN THIS PERIOD'S SEVERE WEATHER ACTIVITY. HEIGHT FALLS ALONG THE W CST EXPECTED TO RESULT IN A REBOUND OF SUBTROPICAL RIDGE OVER THE SRN RCKYS. THIS...IN TURN...SHOULD INDUCE AMPLIFICATION OF DOWNSTREAM SHORTWAVE IMPULSE NOW OVER WRN PORTIONS OF THE CNTRL/SRN PLNS AS THE SYSTEM CONTINUES E/NE TO THE LWR OH/TN VLYS BY 12Z FRIDAY. DEVELOPING SURFACE WAVE NOW IN ERN OK /PARTIALLY MASKED BY RECENT CONVECTIVE OUTFLOW/ IS LINKED TO THE PLAINS SHORTWAVE TROUGH. THE WAVE SHOULD REDEVELOP E TO THE NE AR/W TN AREA THIS AFTERNOON...AND NE INTO THE OH VLY TONIGHT. ...OK/NE TX INTO LWR TN VLY.... COUPLED JET STRUCTURE AND UPPER LEVEL DIFFLUENCE ASSOCIATED WITH AFOREMENTIONED SHORTWAVE IMPULSE EXPECTED TO KEEP WIDESPREAD AREA OF CONVECTION/STORMS NOW OVER OK/NRN AR AND SRN MO MOVING GENERALLY E/NE TODAY. SURFACE HEATING SHOULD SUPPORT MODERATE DESTABILIZATION OF REGION ON SRN/ERN PERIPHERY OF COMPLEX CONVECTIVE SYSTEM...WITH MUCAPE RANGING FROM 1000 TO PERHAPS 2000 J/KG FROM SE OK/NE TX ACROSS SRN AR INTO W TN. THE STRONGEST LOW LEVEL CONVERGENCE SHOULD SHIFT E/NE INTO ERN AR/W TN THIS AFTERNOON AS LOW LEVEL FLOW CONTINUES TO VEER AND SURFACE WAVE REDEVELOPS ENEWD. WHILE MID LEVEL TEMPERATURES WILL REMAIN FAIRLY WARM...30-40 KT DEEP WSWLY SHEAR SHOULD SUPPORT A FEW BANDS/CLUSTERS OF SUSTAINED AFTERNOON/EARLY EVENING STORMS. EMBEDDED BOWING SEGMENTS MAY YIELD LOCALLY DAMAGING WIND AND PERHAPS MARGINALLY SEVERE HAIL...ESPECIALLY OVER NE AR...WRN PORTIONS OF TN/KY AND POSSIBLY NRN MS. THE STORMS SHOULD WEAKEN LATER THIS EVENING AS FORCING FOR ASCENT/STRONGEST SHEAR MOVE BEYOND LOW LEVEL INSTABILITY AXIS. ...NWRN/CNTRL TX... DEGREE OF LARGE SCALE FORCING FOR ASCENT APPEARS MORE NEBULOUS ATTM FOR NW/N CNTRL TX TODAY AS MAIN SRN BRANCH IMPULSE AMPLIFIES ENEWD. NEAR THE SURFACE...HOWEVER...VERY MOIST/SOMEWHAT CONFLUENT FLOW WILL CONTINUE TO IMPINGE UPON WEAKENING COLD FRONTAL SURGE NOW NEAR CDS. A SUBSTANTIAL CAP WILL REMAIN PRESENT...ESPECIALLY WITH WWD EXTENT ACROSS THE STATE. BUT GIVEN FAIRLY STRONG DIURNAL HEATING...BOUNDARY LAYER CONVERGENCE MAY BE SUFFICIENT TO SUPPORT TSTM INITIATION BY LATE AFTERNOON FROM NEAR ABI/BGS NEWD TO NEAR SEP/MWL. MODEST DEEP SHEAR WITH A SIGNIFICANT DIRECTIONAL COMPONENT... COUPLED WITH STRONG INSTABILITY /MUCAPE TO 2000 J PER KG/...MAY SUPPORT A FEW ROTATING STORMS WITH AN ENHANCED THREAT FOR HAIL/DAMAGING WIND. CONCENTRATED AREA OF DEVELOPMENT AND DRY AIR ALOFT SUGGEST DECENT POTENTIAL FOR COLD POOL DEVELOPMENT...WITH RESULTING CLUSTER LIKELY TO MOVE GENERALLY ESE ACROSS CNTRL TX TONIGHT/EARLY FRIDAY. ...ERN NM/W TX... ESELY POST-FRONTAL UPSLOPE FLOW WILL BEAR WATCHING FOR CONVECTIVE INITIATION W OF THE CAP ROCK FROM THE TX S PLNS WWD INTO ERN NM. WARMING MID LEVEL TEMPERATURES AND ABSENCE OF LARGE SCALE FORCING FOR ASCENT SHOULD...HOWEVER...KEEP ANY SUCH DEVELOPMENT QUITE ISOLATED. IF STORMS DO FORM...DEEP SHEAR WILL BE FAVORABLE FOR SUSTAINED SUPERCELLS. ...NRN MID ATLANTIC/NEW ENG... LOW AMPLITUDE SHORT WAVE TROUGH...IN CONJUNCTION WITH ENHANCED DEEP SHEAR/TROPICAL INFLOW ASSOCIATED WITH CONFLUENCE BAND DOWNSTREAM FROM HRCN OPHELIA...WILL CREATE ENVIRONMENT FAVORABLE FOR A FEW STRONG STORMS IN THE SRN NEW ENG/NRN MID ATLANTIC REGION TODAY. HEATING SHOULD BOOST MUCAPE TO AROUND 1500 J/KG BY THIS AFTERNOON...BUT WEAK LAPSE RATES SHOULD LIMIT ANY FURTHER DESTABILIZATION. NEVERTHELESS...MODERATE UNIDIRECTIONAL SWLY FLOW WITH 30+ KT DEEP SHEAR...POSSIBLE DRY AIR IN THE 850-700 LAYER /PER CHH RAOB/...SUGGEST THAT SOME RISK WILL EXIST FOR GUSTY WINDS AND POSSIBLY SMALL HAIL IN SOME STORMS. ...NC/VA/SRN DELMARVA CST... PROXIMITY OF HURRICANE OPHELIA WILL CONTINUE TO PROVIDE AT LEAST SOME RISK FOR AN ISOLATED TORNADO OR DAMAGING CONVECTIVE GUST TODAY. ..AFWA.. 09/15/2005 ...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. CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z |