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    Day 2 Outlook >
Feb 24, 2017 0600 UTC Day 1 Convective Outlook
Click to see valid 1Z - 12Z Day 1 Convective Outlook
Updated: Fri Feb 24 05:49:40 UTC 2017 (Print Version | 20170224 1200Z Day 1 shapefile | 20170224 1200Z Day 1 KML)
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 Forecast Discussion
   SPC AC 240549

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1149 PM CST Thu Feb 23 2017

   Valid 241200Z - 251200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   SOUTHERN LOWER MICHIGAN...CENTRAL AND EASTERN INDIANA...WESTERN AND
   CENTRAL OHIO...AND PARTS OF NORTHERN KENTUCKY...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE
   ENHANCED RISK AREA...AND EXTENDING SOUTHWARD INTO PARTS OF
   TENNESSEE...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SURROUNDING THE
   SLIGHT RISK AREA...EXTENDING FROM THE UPPER GREAT LAKES TO THE
   SOUTHERN APPALACHIANS...

   ...SUMMARY...
   Strong to severe thunderstorms are forecast to affect portions of
   the southern Great Lakes, Ohio and Tennessee Valleys on Friday and
   Friday night.  The primary threat appears to be damaging wind, but
   some hail and a couple of tornadoes will also be possible.

   ...Synopsis...
   An upper short-wave trough -- embedded within broader/longer-wave
   troughing -- is forecast to shift out of the Plains and across the
   mid and lower Missouri valley through the day.  By evening, the
   trough is progged to continue eastward across the mid and upper
   Mississippi Valleys, and eventually into the Midwest/Great Lakes
   region as it acquires neutral to slightly negative tilt with time.

   As the upper system advances/sharpens, a surface low in the vicinity
   of western Illinois early in the day is forecast to move across
   Illinois and northwestern Indiana through the afternoon, and then
   across Michigan toward Lake Huron through the latter stages of the
   period.  Ahead of the low, a warm front is forecast to advance
   northward across the lower Great Lakes into southern Canada, while a
   cold front sweeps eastward across the Ohio/Tennessee/Mississippi
   valleys and reaches the Appalachian crest by the end of the period.

   ...Great Lakes region southward to the southern Appalachians...
   Showers and scattered thunderstorms are forecast to be ongoing from
   parts of northeast Illinois/southeast Wisconsin eastward into the
   northeast U.S. at the start of the period, north of a warm front
   extending eastward across the Midwest.  Modest low-level moisture
   into the warm sector /50s surface dewpoints/ beneath an elevated
   mixed layer advecting northeast across the region should keep the
   warm sector capped -- likely until late afternoon.  Eventually
   however, as the surface low moves northeast toward southern lower
   Michigan and the trailing cold front advances into Indiana, limited
   diurnal heating combined with persistent ascent is expected to
   steadily/gradually weaken the cap, eventually allowing development
   of isolated to scattered thunderstorms.  Initial storm mode may be
   cellular, but upscale growth into a broken line of storms is
   expected, which should expand southward along the advancing front
   through the evening hours.

   Though degree of shear will be sufficient for supercells, somewhat
   veered low-level flow and tendency for more linear storm mode should
   limit overall tornado potential.  Greatest risk for supercell
   tornadoes should exist during the afternoon with initial convective
   development, and possibly near the retreating warm front where more
   backed low-level winds should exist.  With time, risk should evolve
   toward primarily damaging winds, though an isolated QLCS tornado or
   two, as well as marginally severe hail, will be possible through the
   evening and into the overnight hours.  It appears at this time that
   the greatest severe risk will exist from late afternoon/early
   evening through midnight or an hour or two later, across southern
   lower Michigan, eastern Indiana, western Ohio, and northern Kentucky
   -- coincident with the Enhanced Risk area.  Storms should eventually
   begin to diminish in intensity given weaker instability expected
   into the upper Ohio valley/lower Great Lakes region, but risk may
   linger across the southern Appalachians region through the end of
   the period.

   ..Goss/Picca.. 02/24/2017

   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z

        
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Page last modified: February 24, 2017
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