Mar 15, 2012 1630 UTC Day 1 Convective Outlook | |
Updated: Thu Mar 15 16:37:26 UTC 2012 | |
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. |
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. |
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. |
SPC AC 151604 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK ISSUED BY 15TH OWS SCOTT AIR FORCE BASE IL 1104 AM CDT THU MAR 15 2012 VALID 151630Z - 161200Z ...THERE IS A SLGT RISK OF SVR TSTMS OZARKS TO OH/TN VALLEYS AND ERN GREAT LAKES... ...SYNOPSIS... RELATIVELY WEAK SWLY MID LEVEL FLOW EXISTS OVER MUCH OF THE U.S. THIS MORNING WITH STRONGER WINDS ALOFT CONFINED TO THE NORTHWEST/NRN PLAINS AND NRN NEW ENGLAND. ELSEWHERE...A BROAD BELT OF 10-30KT 500MB FLOW EXTENDS FROM THE SOUTHWEST TO THE OH VALLEY ATOP SLIGHTLY STRONGER LOW LEVEL SWLY FLOW ON THE WRN FLANK OF ANTICYCLONE ANCHORED OVER THE SOUTHEAST AND ADJACENT ATLANTIC. MOST PRONOUNCED HEIGHT FALLS THIS PERIOD WILL OCCUR IN ASSOCIATION WITH A PACIFIC TROUGH SPREADING INLAND ACROSS WA/ORE. A LOW AMPLITUDE SHORT WAVE TROUGH EMBEDDED WITHIN THE WEAK FLOW ACROSS THE PLAINS...IN TANDEM WITH A SOMEWHAT STRONGER IMPULSE OVER CANADA...WILL RESULT IN WEAK HEIGHT FALLS SPREADING EAST FROM SRN PLAINS TO THE OH VALLEY/GREAT LAKES THROUGH TONIGHT. ...OZARKS TO OH/TN VALLEYS AND ERN GREAT LAKES... ANOMALOUSLY HIGH PW/MOISTURE AND MEAGER MID LEVEL FLOW/SHEAR WILL CONTINUE TO SUPPORT AN ATYPICAL SETUP FOR MID-MARCH TSTM DEVELOPMENT ACROSS AREAS FROM THE OZARKS ACROSS THE MID/LOWER MS VALLEY TO THE MIDWEST THROUGH TODAY. ONGOING STORMS FROM SRN IND TO OH/KY/WV AND ERN TN ARE IN RESPONSE TO MASS CONVERGENCE AND ISENTROPIC LIFT ON THE ERN EDGE OF EXTENSIVE CNTRL U.S. EML PLUME. RECENT TRENDS AND UPWIND PROPAGATION VECTORS SUGGEST THE MCS ROOTED ABOVE THE BOUNDARY LAYER IN OH/WV MAY PRODUCE LOCALLY HEAVY RAIN THIS MORNING. DESPITE THE LACK OF STRONGER VERTICAL SHEAR OVER THE AREA BASED ON MORNING SOUNDINGS AND OBJECTIVE ANALYSIS DATA SOME HAIL POTENTIAL WILL PERSIST DUE TO STEEP LAPSE RATES AND LOW FREEZING LEVELS. ...ARKLATEX AREA... CONTINUING TO MONITOR AREA FOR ISOLATED SEVERE POTENTIAL AS WEAK SHORTWAVE AND WEAK SPEED MAX MOVES EASTWARD FROM NORTHERN TX. SHEAR CONDITIONS REMAIN WEAK, HOWEVER ANALYSIS DATA AND SATELLITE INDICATE AMPLE EXHAUST IN UPPER TROPOSPHERE WITH LOW LEVEL INSTABILITY ALREADY PRESENT. ...ELSEWHERE... THE AFOREMENTIONED WEAK CIRCULATION/DISTURBANCE SPREADING EAST ACROSS THE SRN PLAINS THIS MORNING WILL BE ACCOMPANIED BY 10-30KT MID LEVEL FLOW PER LATEST PROFILER AND VWP OBSERVATIONS. LIFT ASSOCIATED WITH THIS IMPULSE WILL SPREAD EAST TOWARD THE MIDWEST AND MS VALLEY ATOP THE BROAD LOW LEVEL WARM/MOIST CONVEYOR BELT. POCKETS OF GREATER DIURNAL HEATING WILL CONTRIBUTE TO AREAS OF STRONG DESTABILIZATION OVER THE CNTRL AND SRN U.S. THIS AFTERNOON. MODEL GUIDANCE SUGGESTS THAT WEAKER INHIBITION EAST OF THE GREAT PLAINS SHOULD BE OVERCOME/ELIMINATED THROUGH A COMBINATION OF BACKGROUND ASCENT AND BOUNDARY LAYER DIABATIC HEATING/MIXING. MULTICELLULAR TSTM DEVELOPMENT IS EXPECTED IN THIS REGIME AND DESPITE LACK OF STRONGER DEEP-LAYER SHEAR THE THREAT FOR SCATTERED TO NUMEROUS HAIL AND GUSTY WIND EVENTS SEEMS POSSIBLE INTO THIS EVENING. IF GREATER STORM-SCALE ORGANIZATION CAN DEVELOP/EVOLVE THROUGH THE DAY IT MAY BE POSSIBLE TO PROVIDE A MORE DETAILED/FOCUSED TSTM WIND THREAT AREA BUT HAIL APPEARS TO BE THE PREDOMINANT SEVERE THREAT AT THIS TIME. WEAK FRONT WILL AID LIFT AMIDST INCREASINGLY UNSTABLE AIRMASS ACROSS LOWER MI AND OH LATER TODAY TO SUPPORT A FEW CLUSTERS/LINES OF STORMS ALSO CAPABLE OF PRODUCING HAIL AND GUSTY WINDS. ..15_OWS.. 03/15/2012 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z