Sep 19, 2014 0600 UTC Day 2 Convective Outlook
Updated: Fri Sep 19 06:03:16 UTC 2014 (20140919 0600Z Day 2 shapefile | 20140919 0600Z Day 2 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20140919 0600 UTC Day 2 Outlook Graphic
Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 59,420 17,300,515 Chicago, IL...Milwaukee, WI...Grand Rapids, MI...Aurora, IL...Rockford, IL...
Probabilistic Graphic
20140919 0600 UTC Day Probabilitic Graphic
Probability of severe weather within 25 miles of a point.
Hatched Area: 10% or greater probability of significant severe within 25 miles of a point.
Prob. Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 60,635 17,433,033 Chicago, IL...Milwaukee, WI...Grand Rapids, MI...Aurora, IL...Rockford, IL...
5 % 330,013 19,263,601 Detroit, MI...Kansas City, MO...Toledo, OH...Fort Wayne, IN...Madison, WI...
   SPC AC 190603

   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0103 AM CDT FRI SEP 19 2014

   VALID 201200Z - 211200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE LOWER GREAT
   LAKES AND UPPER MIDWEST...

   ...SUMMARY...
   STRONG TO SCATTERED SEVERE THUNDERSTORMS ARE EXPECTED DURING
   SATURDAY OVER PARTS OF THE GREAT LAKES AND MIDWEST REGIONS. A FEW OF
   THE SEVERE STORMS MAY PRODUCE HAIL AND HIGH WINDS. OTHER STRONG TO
   ISOLATED SEVERE THUNDERSTORMS WITH GUSTY WINDS AND HAIL ARE POSSIBLE
   FROM THE MID-MISSISSIPPI VALLEY WESTWARD ACROSS THE CENTRAL ROCKIES
   TO THE SOUTHERN GREAT BASIN.

   ...SYNOPSIS...
   PROGRESSIVE AND MODESTLY AMPLIFIED MID-LEVEL FLOW WILL EXIST FROM
   THE NORTHERN PLAINS EAST ACROSS THE GREAT LAKES TO NEW ENGLAND ON
   SATURDAY. A LEADING SHORTWAVE TROUGH CURRENTLY CROSSING THE NORTHERN
   ROCKIES WILL MOVE EAST TO THE UPPER MS VALLEY THROUGH FRIDAY AND
   THEN UNDERGO FURTHER AMPLIFICATION OVER THE GREAT LAKES ON SATURDAY
   AS A STRONGER SHORTWAVE IMPULSE ACCELERATES SOUTHEAST OUT OF
   SOUTH-CENTRAL CANADA. THE COLD FRONT ASSOCIATED WITH THE LEADING
   DISTURBANCE IS FORECAST TO SPREAD SOUTHEAST INTO SOUTHERN WI/LOWER
   MI AND PARTS OF INDIANA/IL COINCIDENT WITH DAYTIME
   HEATING/DESTABILIZATION AND STRENGTHENING DEEP-LAYER WIND FIELDS.

   A CLOSED MID/UPPER LOW NOW TAKING SHAPE OVER CA IS FORECAST TO DRIFT
   INLAND/EASTWARD THROUGH LATE SATURDAY. WEAK HEIGHT FALLS ON THE
   EASTERN FLANK OF THIS SYSTEM WILL IMPINGE UPON ANTECEDENT
   SUB-TROPICAL MOISTURE PLUME ACROSS THE SOUTHERN GREAT BASIN.

   ...LOWER GREAT LAKES/UPPER MIDWEST...
   SCATTERED CONVECTION MAY BE ONGOING AT THE START OF THE PERIOD ALONG
   AND AHEAD OF A MODEST COLD FRONT SPREADING SOUTHEAST FROM THE UPPER
   MS VALLEY AND NORTHERN LOWER MI. LIFT ALONG THE FRONT SHOULD
   INCREASE THROUGH THE DAY AS STRONGER MID-LEVEL HEIGHT FALLS DEVELOP
   OVER WI/LM. RELATIVELY STOUT WEST-SOUTHWESTERLY LOW-LEVEL FLOW
   SHOULD AID MOISTURE TRANSPORT ACROSS THE UPPER MIDWEST/LOWER
   MI...WITH SURFACE DEWPOINTS LIKELY CLIMBING INTO THE LOW-MID 60S F
   BY AFTERNOON. WHILE EARLY DAY STORMS MAY STRUGGLE FROM LACK OF
   STRONGER SURFACE-BASED DESTABILIZATION...SUFFICIENTLY STEEP
   MID-LEVEL LAPSE RATES AROUND 7 C/KM MAY EXIST ACROSS SOUTHERN WI TO
   SUPPORT STRONGER UPDRAFTS AND PERHAPS HAIL. STRONGER DESTABILIZATION
   APPEARS LIKELY TO EVOLVE FROM MS VALLEY EASTWARD TO NORTHERN IL/IND
   THROUGH THE AFTERNOON. A CORRIDOR OF SBCAPE ON THE ORDER OF 800-1200
   J/KG AHEAD OF THE FRONT AND CO-LOCATED WITH STRENGTHENING
   UNIDIRECTIONAL DEEP-LAYER SHEAR OF 35-40KT COULD SUPPORT THE
   DEVELOPMENT OR MORE ORGANIZED/PERSISTENT STORMS FROM THE IL/WI
   BORDER EAST TO NORTHERN IND AND LOWER MI. THIS ACTIVITY MAY EVOLVE
   INTO FAST-MOVING LINE SEGMENTS AND OR A FEW SUPERCELLS THROUGH THE
   EARLY EVENING HOURS. DESPITE A CONTINUATION OF LIFT ALONG THE
   ADVANCING FRONT...ISOLATED TO SCATTERED HIGH WIND AND SEVERE HAIL
   THREATS ARE LIKELY TO WANE BY EVENING AS EASTWARD-MOVING STORMS
   ENCOUNTER DIMINISHING INSTABILITY.

   ...GREAT BASIN...
   STRONGER QG FORCING FOR ASCENT IS INDICATED IN LATEST NAM ACROSS THE
   SOUTHERN GREAT BASIN /EASTERN NV AND SOUTHWEST UT/ BY EARLY SATURDAY
   EVENING AS MID/UPPER LOW DRIFTS EAST. LIFT WITH THIS SYSTEM WILL ACT
   ON A RELATIVELY MOIST AIRMASS WHERE STRONGER DIURNAL HEATING WILL
   LIKELY CONTRIBUTE TO A DEEPLY MIXED BOUNDARY LAYER. EXPECT SCATTERED
   HIGH-BASED STORMS TO INCREASE/PERSIST AS LARGE-SCALE ASCENT SPREADS
   EAST AND BELT OF 30-40KT SOUTHERLY MID-LEVEL FLOW SPREADS
   NORTH/NORTHEAST FROM EASTERN NV INTO WESTERN UT. A COUPLE OF
   STRONGER CORES MAY RESULT IN MARGINAL HAIL AND/OR STRONG DOWNBURST
   WINDS.

   ...MN/UPPER MS VALLEY...
   AS A STRONG SHORTWAVE TROUGH DEVELOPS SOUTHEAST OUT OF CANADA
   THROUGH LATE AFTERNOON...DEEP-LAYER ASCENT AND LOWERING STATIC
   STABILITY WITHIN LEFT EXIT REGION OF 70-80KT MID-LEVEL JET STREAK
   WILL MOVE FROM NORTHERN MN TO NORTHWEST WI. RESIDUAL LOW-LEVEL
   MOISTURE IN THE WAKE OF LEADING FRONTAL PASSAGE...IN COMBINATION
   WITH COLDER TEMPERATURES ALOFT...SHOULD BE ADEQUATE FOR AT LEAST
   LOW-TOPPED CONVECTION AMIDST INTENSIFYING WIND FIELDS. IT SEEMS
   POSSIBLE THAT A COUPLE OF STORMS COULD PRODUCE HAIL AND GUSTY WINDS
   BEFORE NIGHTFALL.

   ..CARBIN.. 09/19/2014

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