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)The SPC is forecasting ...severe thunderstorms expected over parts of the mid-mississippi and ohio valleys into michigan today through early tonight.... Please read the latest public statement about this event. View What is a Watch? clip.
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| Probabilistic Tornado Graphic | |||||||||||||||||
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| 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 | |||||||||||||||||
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| 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 | |||||||||||||||||
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| 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 171259 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0659 AM CST SUN NOV 17 2013 VALID 171300Z - 181200Z ...THERE IS A HIGH RISK OF SVR TSTMS OVER PARTS OF ILLINOIS...INDIANA...WESTERN OHIO...AND SRN MICHIGAN... ...THERE IS A MDT RISK OF SVR TSTMS SURROUNDING THE HIGH RISK AREA...FROM MUCH OF KENTUCKY AND EASTERN MISSOURI NEWD INTO THE LWR GRT LKS... ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE HIGH AND MDT RISK AREAS...FROM PARTS OF THE LWR MS VLY NEWD TO THE MID ATLANTIC STATES/WRN NEW ENGLAND... ...SYNOPSIS... SVR WEATHER OUTBREAK...WITH SIGNIFICANT TORNADOES AND WIDESPREAD DMGG WINDS...EXPECTED OVER THE OH VLY AND SRN GREAT LKS REGION TODAY/TNGT... POTENT CNTRL PLNS SHORTWAVE TROUGH...WITH MID-LVL WIND SPEEDS AOA 100 KTS...WILL SWEEP E ACROSS THE NRN OZARKS/MID MS VLY LATER TODAY...AND ENE ACROSS THE OH VLY BY EARLY TNGT...BEFORE TURNING MORE NEWD ACROSS LWR GRT LKS/NRN APPALACHIANS EARLY MON. THE SYSTEM WILL BE ACCOMPANIED BY A RAPIDLY DEEPENING SFC LOW THAT SHOULD TRACK FROM SE IA THIS MORNING INTO NRN LWR MI BY EARLY TNGT. COLD FRONT TRAILING S AND SW FROM THE LOW...NOW EXTENDING THROUGH NW MO AND FAR ERN KS...SHOULD ACCELERATE E/SEWD THROUGH THE DAY...OVERTAKING PRE-FRONTAL TROUGH/DRY LINE OVER MO...AND REACHING WRN OH/N CNTRL KY THIS EVE. THE FRONT SHOULD CONTINUE RAPIDLY E ACROSS THE LWR GRT LKS...THE MID ATLANTIC STATES...AND WRN NEW ENGLAND LATER TNGT/EARLY MON. COMBINATION OF VERY STRONG TO INTENSE WIND FIELD WITH APPRECIABLE SFC-BASED INSTABILITY OVER A FAIRLY WIDE AREA WILL YIELD A BROAD SWATH OF SVR WEATHER FROM ERN PORTIONS OF THE MID MS VLY TO THE MID-ATLANTIC STATES AND NORTHEAST. THE GREATEST/MOST CONCENTRATED SVR THREAT...INCLUDING POTENTIALLY STRONG AND/OR LONG-TRACK TORNADOES...SHOULD FOCUS OVER THE OH VLY AND ADJACENT PARTS OF THE MIDWEST BEGINNING LATER THIS MORNING AND CONTINUING THROUGH EARLY TNGT. ...MID MS/OH/LWR TN VLYS NEWD TO LWR GRT LKS/WRN NEW ENGLAND TODAY THROUGH EARLY MON... LATEST OBSERVED DATA SHOW SFC LOW ALREADY STARTING TO DEEPEN OVER S CNTRL IA...WITH LOW-LVL MOIST AXIS BECOMING BETTER DEFINED ACROSS CNTRL MO...ALONG AND E OF PRE-COLD-FRONTAL TROUGH. AT UPR LVLS...SATELLITE SUGGESTS THAT EXIT REGION OF CNTRL PLNS JET STREAK WILL CONTINUE EWD ACROSS IA/NRN MO THROUGH MID-MORNING...AND INTO NRN/CNTRL IL BY MIDDAY. COMBINATION OF INCREASING ASCENT/MID-LVL COOLING WITH THE JET STREAK...CONTINUED LOW-LVL MOISTURE INFLOW /WITH SFC DEWPOINTS RISING INTO THE 60 F/...AND MODEST SFC HEATING SHOULD SUPPORT TSTM DEVELOPMENT ALONG AND AHEAD OF MERGING COLD FRONT/TROUGH BY MID TO LATE MORNING OVER ERN MO AND CNTRL/NRN IL. OTHER STORMS SHOULD CONTINUE TO INCREASE IN ZONE OF STRENGTHENING WAA FROM ERN IA INTO FAR NRN IL/SRN WI. INTENSITY OF LOW TO MID-LVL WIND FIELD...PARTICULARLY WITH 700 MB SPEEDS INCREASING TO BETWEEN 50 AND 70 KTS...IN CONJUNCTION WITH SUBSTANTIAL SFC-BASED BUOYANCY /SBCAPE RANGING FROM 500-1000 J PER KG/...WILL YIELD AN ENVIRONMENT VERY FAVORABLE FOR LONG-LIVED DISCRETE TO SEMI-DISCRETE SUPERCELLS...BEGINNING IN FAR ERN MO...AND THEN CONTINUING ENE ACROSS MUCH OF IL...IND...FAR SRN WI...SRN MI AND WRN OH THROUGH THE REMAINDER OF THE DAY. WHILE STRENGTH OF SHEAR /RELATIVE TO DEGREE OF LOW-LVL CONVERGENCE AND BUOYANCY/...AND DESTRUCTIVE INTERFERENCE BETWEEN STORMS MAY PROVE TO BE LIMITING FACTORS...SETUP NONETHELESS APPEARS CAPABLE OF SUPPORTING A FEW LONG-TRACK/POTENTIALLY STRONG TORNADOES. WITH TIME...ESPECIALLY THIS EVE AS LINEAR FORCING INCREASES ALONG STRENGTHENING COLD FRONT...THE STORMS SHOULD EVOLVE INTO SEVERAL BROKEN LINES...WITH EMBEDDED LEWPS AND RESIDUAL SUPERCELL CIRCULATIONS CONTINUING TO POSE A RISK FOR DMGG WIND EWD INTO THE NRN AND CNTRL APPALACHIANS. WHILE TIME OF DAY WILL BE UNFAVORABLE...STRENGTH OF WIND FIELD/DCVA...AND PRESENCE OF EXITING CONVECTIVE BAND SUGGEST AT LEAST A CONDITIONAL RISK FOR DMGG WINDS EARLY MON EWD INTO PARTS OF NEW ENGLAND AND THE MID-ATLANTIC STATES. FARTHER S...MID-LVL WARMING ON S SIDE OF AMPLIFIED MIDWESTERN JET STREAK MAY SOMEWHAT HINDER STORM DEVELOPMENT/DELAY SVR THREAT IN VERY MOIST/MODERATELY-SHEARED ENVIRONMENT AHEAD OF COLD FRONT OVER THE LWR TN AND LWR MS VLYS. NEVERTHELESS...AT LEAST A LOW CONDITIONAL THREAT FOR SVR STORMS /INCLUDING A FEW SUPERCELLS WITH A TORNADO OR TWO/...WILL EXIST IN THIS REGION THROUGH EARLY TNGT...ESPECIALLY IN ANY AREAS RECEIVING ENHANCED AFTN SFC HEATING. ..CORFIDI/PETERS.. 11/17/2013 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z |