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