Oct 30, 2013 1300 UTC Day 1 Convective Outlook | |||||||||
Updated: Wed Oct 30 12:57:46 UTC 2013 ( | ) | |||||||||
Probabilistic to Categorical Outlook Conversion Table |
Categorical Graphic | |||||||||
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Probabilistic Tornado Graphic | |||||||||
Probability of a tornado within 25 miles of a point. Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point. |
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Probabilistic Damaging Wind Graphic | |||||||||
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point. |
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Probabilistic Large Hail Graphic | |||||||||
Probability of hail 1" or larger within 25 miles of a point. Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point. |
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SPC AC 301253 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0753 AM CDT WED OCT 30 2013 VALID 301300Z - 311200Z ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS LOWER MO VALLEY ACROSS CENTRAL/SRN PLAINS TO SW TX... ...SYNOPSIS... MAIN UPPER-AIR FACTOR FOR THIS PERIOD AND BEYOND WILL BE HIGH-AMPLITUDE SYNOPTIC TROUGH -- NOW MANIFEST AS NNE-SSW-ELONGATED CYCLONE COVERING MUCH OF GREAT BASIN AND CENTRAL/NRN ROCKIES REGIONS. THIS FEATURE IS FCST TO EVOLVE INTO MORE PROGRESSIVE/OPEN-WAVE BUT STILL HIGHLY AMPLIFIED TROUGH THROUGH PERIOD. STG BASAL SHORTWAVE TROUGH -- EVIDENT IN MOISTURE CHANNEL IMAGERY OVER LAS REGION -- IS FCST TO PIVOT EWD ACROSS AZ TODAY...REACHING SWRN CO...NWRN NM AND SERN AZ BY 00Z...THEN STRENGTHENING AND ACCELERATING EWD TO SRN HIGH PLAINS BY END OF PERIOD. MEANWHILE...COPIOUS MID-UPPER LEVEL MOISTURE CONTINUES TO STREAM NEWD OFF WHAT IS NOW NERN PAC T.D. RAYMOND...OVER NRN MEX AND MUCH OF TX/OK/AR/LA. AT SFC...STG/INITIALLY QUASISTATIONARY FRONTAL ZONE EXTENDED FROM LOW OVER NERN KS/NWRN MO REGION SWWD ACROSS S-CENTRAL KS AND NWRN OK TO NRN TX PANHANDLE...TO ANOTHER LOW OVER SERN CO. PAC COLD FRONT WAS EVIDENT FROM THAT LOW SWWD ACROSS CENTRAL/SRN NM. LATTER FRONT WILL MOVE EWD ONLY SLOWLY AT FIRST...THEN BECOME BETTER-DEFINED WITH TIME THIS EVENING AND OVERNIGHT...OVERTAKING DRYLINE FROM N-S ACROSS SRN HIGH PLAINS. BY 12Z...FRONTAL-WAVE LOW SHOULD EVOLVE OVER NRN OK...WITH COLD FRONT SWWD ACROSS W TX. ...CENTRAL/SRN PLAINS...LOWER MO VALLEY... SE-NW ALIGNED BELT OF SCATTERED TSTMS...WITH ISOLATED SVR HAIL CORES POTENTIALLY EMBEDDED WITHIN...IS MOVING NEWD ACROSS ERN NEB AND LOWER MO VALLEY REGION. THIS ACTIVITY IS FOLLOWED BY ADDITIONAL ELEVATED CONVECTION INCREASING IN COVERAGE/INTENSITY AS IT MOVES NEWD OUT OF PORTIONS CENTRAL KS...ALSO N OF SFC FRONT. REF SPC MESOSCALE DISCUSSION 1980 FOR NEAR-TERM DETAILS. OTHERWISE...THREE RELATIVE CONCENTRATIONS OF POTENTIAL NOW ARE APPARENT WITHIN WHAT OTHERWISE APPEARS AS POORLY FOCUSED...CONVECTIVELY MESSY AND VERY BROAD SVR RISK AREA. 1. CORRIDOR FROM CENTRAL/SE TX INTO OK THROUGH AFTN... THIS REGIME WILL REMAIN ASSOCIATED WITH BROAD LLJ AND RELATED WAA/MOISTURE-TRANSPORT PROCESS...CHARACTERIZED BY WEAK INSTABILITY BUT FAVORABLE LOW-LEVEL HODOGRAPHS AND GRADUALLY INTENSIFYING DEEP SHEAR. EPISODES OF WIDELY SCATTERED TO SCATTERED NON-SVR TSTMS IN CLUSTERS ALREADY HAVE BEEN OCCURRING FOR SEVERAL HOURS OVER THIS AREA...INCREASING OVERALL IN COVERAGE. MORE DEVELOPMENT IS LIKELY THROUGHOUT TODAY ON ITS WRN FRINGES AS A. LLJ REPLENISHES LOW-LEVEL THETAE AWAY FROM PERSISTENT CONVECTIVE OVERTURNING AND B. DESPITE ABUNDANT CLOUD COVER...DIFFUSE DIABATIC HEATING YIELDS STEADILY INCREASING SFC-BASED BUOYANCY THROUGH LATE AFTN. 2. EVENING/OVERNIGHT CONVECTIVE CORRIDOR FROM SW TX TO SRN OK... DEEP-LAYER LIFT AND SHEAR EACH WILL INCREASE...IN ENVIRONMENT CHARACTERIZED BY RICH LOW-LEVEL MOISTURE WITH SFC DEW POINTS COMMONLY UPPER 60S TO LOW 70S F. THIS PROCESS SHOULD HELP TO MAINTAIN SFC-BASED EFFECTIVE INFLOW PARCELS WITH WEAK CINH...BENEATH STEEP MIDLEVEL LAPSE RATES...IN SUPPORT OF MOSTLY CLUSTERED TO QUASI-LINEAR CONVECTION. THOUGH UPPER-LEVEL LAPSE RATES MAY BE MITIGATED SOMEWHAT IN PLUME OF MOISTURE FROM RAYMOND...MLCAPE/MUCAPE IN 1500-2000 J/KG MAY BE ATTAINABLE AWAY FROM PERSISTENT/ANTECEDENT CONVECTIVE AREAS. LLJ WILL KEEP 0-1 KM SHEAR VALUES AND HODOGRAPH LARGE...THOUGH WEAKNESSES ABOVE THAT MAY LIMIT TOTAL LOW-LEVEL SHEAR. STILL...CONDITIONAL TORNADO RISK IS EVIDENT ON TOP OF WIND/HAIL THREAT...DEPENDENT LARGELY ON MAINTENANCE OF ANY EMBEDDED OR DISCRETE SUPERCELL MODES THAT CAN DEVELOP. 3. PORTIONS SRN KS...WRN OK AND W TX TONIGHT... AS AFOREMENTIONED SHORTWAVE TROUGH APCHS SRN HIGH PLAINS...HEIGHT/THERMAL GRADIENTS ALOFT WILL TIGHTEN CONSIDERABLY AND ADVANCE EWD AMIDST PRONOUNCED DCVA AND STG HEIGHT FALLS. RIGHT-ENTRANCE REGION OF AOA 140-KT 250-MB JET STREAK WILL BE PRESENT OVER THIS REGION...ALONG WITH LOW-LEVEL FRONTOGENETIC FORCING. THESE PROCESSES WILL RESULT IN INCREASING DEEP SHEAR... LAPSE RATES AND LIFT OVER WRN FRINGES OF WARM/MOIST SECTOR AFTER DARK. BAND OF SCATTERED TO LOCALLY NUMEROUS TSTMS MAY FORM...OFFERING SVR HAIL...OCNL DAMAGING GUSTS AND LOW BUT NONZERO TORNADO RISK. WHILE THOSE REGIMES REPRESENT MOST PROBABLE SOURCES OF ORGANIZED SVR CONVECTION...PLEASE BEAR IN MIND THAT STRENGTHENING WINDS ALOFT WILL SPREAD OVER SEASONALLY MOIST AND AT LEAST MRGLLY UNSTABLE WARM/MOIST SECTOR ALL PERIOD LONG. AS SUCH...AT LEAST ISOLATED SVR OF ANY TYPE CAN OCCUR IN BETWEEN...ANYWHERE OVER OUTLOOK AREA...THROUGHOUT TODAY AND TONIGHT. ..EDWARDS/COHEN.. 10/30/2013 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z |