Mar 27, 2017 2000 UTC Day 1 Convective Outlook
Updated: Mon Mar 27 20:07:27 UTC 2017 (20170327 2000Z Day 1 shapefile | 20170327 2000Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20170327 2000 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
ENHANCED 42,202 4,471,150 Nashville, TN...Huntsville, AL...Clarksville, TN...Murfreesboro, TN...Jackson, TN...
SLIGHT 108,059 10,943,343 Memphis, TN...Lexington-Fayette, KY...Louisville, KY...Birmingham, AL...Jackson, MS...
MARGINAL 86,924 9,275,426 Cincinnati, OH...Baton Rouge, LA...Montgomery, AL...Knoxville, TN...Hamilton, OH...
Probabilistic Tornado Graphic
20170327 2000 UTC Day 1 Tornado Probabilities 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.
Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 42,319 4,311,700 Nashville, TN...Clarksville, TN...Murfreesboro, TN...Jackson, TN...Decatur, AL...
2 % 47,877 6,341,048 Memphis, TN...Lexington-Fayette, KY...Louisville, KY...Birmingham, AL...Huntsville, AL...
Probabilistic Damaging Wind Graphic
20170327 2000 UTC Day 1 Damaging Wind Probabilities 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.
Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
30 % 35,985 4,075,428 Nashville, TN...Huntsville, AL...Clarksville, TN...Murfreesboro, TN...Jackson, TN...
15 % 113,580 11,313,718 Memphis, TN...Lexington-Fayette, KY...Louisville, KY...Birmingham, AL...Jackson, MS...
5 % 87,496 9,286,110 Cincinnati, OH...Baton Rouge, LA...Montgomery, AL...Knoxville, TN...Hamilton, OH...
Probabilistic Large Hail Graphic
20170327 2000 UTC Day 1 Large Hail Probabilities 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.
Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 13,002 749,707 Jackson, TN...Tupelo, MS...Corinth, MS...Brownsville, TN...Paris, TN...
30 % 17,017 983,141 Jackson, TN...Tupelo, MS...Florence, AL...Corinth, MS...Muscle Shoals, AL...
15 % 130,188 14,128,046 Memphis, TN...Nashville, TN...Lexington-Fayette, KY...Louisville, KY...Birmingham, AL...
5 % 61,876 6,570,396 Cincinnati, OH...Knoxville, TN...Jonesboro, AR...Monroe, LA...Charleston, WV...
   SPC AC 272007

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0307 PM CDT Mon Mar 27 2017

   Valid 272000Z - 281200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   WESTERN AND CENTRAL KENTUCKY...WESTERN AND MIDDLE
   TENNESSEE...NORTHEAST MISSISSIPPI...AND NORTHERN ALABAMA...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE
   ENHANCED RISK AREA FROM THE OHIO VALLEY TO THE LOWER MISSISSIPPI
   VALLEY TO ALABAMA...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SURROUNDING THE
   SLIGHT RISK AREA FROM THE OHIO VALLEY TO LOWER MISSISSIPPI VALLEY...

   ...SUMMARY...
   Scattered to numerous severe thunderstorms are expected across the
   Lower Mississippi and Ohio Valleys into the Tennessee Valley this
   afternoon and evening. Very large hail, damaging winds, and a couple
   tornadoes will be possible.

   ...KY/TN/MS/AL...
   Given the eastern progression of the midlevel shortwave trough and
   the western portions of the severe-weather probabilities have been
   trimmed eastward, while the Enhanced Risk for severe/damaging winds
   has been expanded eastward some across central KY, middle TN, and
   northern AL.  

   ...Far southern IL, southeast MO and eastern AR...
   Given the eastward progression of the midlevel shortwave trough, the
   severe probabilities have been trimmed across parts of far southern
   IL and southeast MO, and shifted east across much of central and
   eastern AR and part of northwest MS, where the severe threat has
   diminished.  The exception is across northeast AR, where moderate
   instability and sufficient bulk shear are maintaining a severe
   threat with storms developing along the cold front.

   ...Northeast LA to northeast AL and northwest GA...
   The severe probabilities have been expanded into more of northeast
   LA/southwest MS and northeast AL into northern GA for an increase
   severe weather threat than was forecast in the earlier outlook.

   ...Eastern KY into southwest WV...
   A leading midlevel shortwave trough appears to be moving across
   eastern KY and eastern AL into western GA.  Forcing for ascent with
   this trough and destabilization into eastern KY to WV suggests the
   severe weather threat needed an eastward expansion.

   ..Peters.. 03/27/2017

   .PREV DISCUSSION... /ISSUED 1130 AM CDT Mon Mar 27 2017/

   ...Lower Ohio/Mississippi River Valleys and Tennessee Valley...
   A low-amplitude shortwave trough over the southern MO late this
   morning will continue generally eastward and reach the middle OH
   River Valley by late tonight. A preceding belt of 40-50 kt
   west-southwesterly mid level winds will continue to overspread an
   increasingly moist, albeit modestly so, warm sector. Ahead of an
   eastward-moving cold front currently across the Ozarks and
   Ark-La-Tex, lower/some middle 60s F surface dewpoints will continue
   to become increasingly common across eastern AR, northern MS into
   western TN, northward into western KY. While warm-sector cloud cover
   has remained semi-prevalent thus far, some cloud breaks are noted in
   visible satellite imagery an additional thinning seems likely in
   concert especially with the eastward-spread mid/high-level dry slot
   as per water vapor satellite imagery.

   Linearly organized convection across far northeast AR/far southeast
   MO late this morning should continue to spread east-northeastward
   and increase in coverage/intensify into northwest TN and
   western/central KY as the downstream air mass continues to moisten
   and destabilize. This activity will pose a damaging wind and severe
   hail risk, although a tornado cannot be ruled out. Farther south,
   other initially more discrete storms should develop within the warm
   sector this afternoon across additional portions of TN, far eastern
   AR, northern MS and eventually northwest AL later this
   afternoon/evening. Here, supercell-favorable wind profiles and steep
   mid-level lapse rates as noted per 12Z observed soundings will
   support large hail potential. A few tornadoes also appear possible,
   particularly around mid/late afternoon into early evening across
   western/middle portions of TN and northern MS and northwest AL. In
   this corridor, a modest westerly component of the mid-level winds
   will coincide with modestly strong low-level shear/SRH.

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z