May 26, 2018 0600 UTC Day 2 Convective Outlook
Updated: Sat May 26 06:01:08 UTC 2018 (20180526 0600Z Day 2 shapefile | 20180526 0600Z Day 2 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20180526 0600 UTC Day 2 Outlook Graphic
Day 2 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 118,262 650,238 Rapid City, SD...Bismarck, ND...Gillette, WY...Mandan, ND...Dickinson, ND...
MARGINAL 227,710 18,892,426 Miami, FL...Tampa, FL...St. Petersburg, FL...Hialeah, FL...Orlando, FL...
Probabilistic Graphic
20180526 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.
Day 2 Prob. Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 117,421 646,062 Rapid City, SD...Bismarck, ND...Gillette, WY...Mandan, ND...Dickinson, ND...
5 % 228,505 18,923,655 Miami, FL...Tampa, FL...St. Petersburg, FL...Hialeah, FL...Orlando, FL...
   SPC AC 260601

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0101 AM CDT Sat May 26 2018

   Valid 271200Z - 281200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
   THE CENTRAL AND NORTHERN HIGH PLAINS...AND EASTWARD ACROSS PARTS OF
   THE DAKOTAS TO NORTHERN MINNESOTA...

   ...SUMMARY...
   Strong/severe storms will be possible across portions of the
   northern and central High Plains and into the Dakotas and northern
   Minnesota.  A couple of brief tornadoes may also be possible in
   conjunction with Alberto as it crosses the eastern Gulf.

   ...Synopsis...
   An upper low centered in the vicinity of the Great Basin will remain
   quasi-stationary on Sunday, though several satellite disturbances
   moving through eastern portions of the low will affect convective
   potential across portions of the High Plains/northern Plains. 
   Otherwise, weak troughing will shift across the Great
   Lakes/Northeast, with ridging largely prevailing elsewhere with the
   exception of the Gulf of Mexico vicinity.

   Over the Gulf, Subtropical Storm Alberto is forecast to be moving
   slowly northward across the eastern Gulf as a Tropical Storm (please
   refer to the latest forecasts from the NHC regarding this system). 
   Elsewhere, the surface pattern will feature persistent lee troughing
   over the High Plains, with a weak surface low possibly moving east
   across the North Dakota vicinity overnight, as hints that a
   convectively enhanced vort max may crest the central U.S. upper
   ridge and shift toward the Upper Great Lakes region can be gleaned
   from the latest model runs.

   ...Central and northern High Plains northeast across northern
   Minnesota...
   Continued northward advection of low-level moisture is expected
   across the High Plains, in conjunction with southerly winds near and
   ahead of the lee trough.  This combined with daytime heating will
   result in moderate destabilization from central and eastern Wyoming
   east/northeast across the Dakotas, and southward across the High
   Plains near/ahead of the lee trough.

   As short-wave energy aloft rotates north-northeastward across the
   High Plains in cyclonic southerly flow ahead of the Great Basin
   system, large-scale ascent should increase through the day.  By
   afternoon, storm development is expected in upslope-favored areas of
   Wyoming, and southward along the lee trough, with clustering/upscale
   growth possible into the evening as a low-level jet increases.

   With moderate south-southwest flow aloft atop a low-level
   south/southeast component, shear supportive of organized/rotating
   storms is expected.  Initial convective development thus may include
   a few supercells, with associated potential for large hail and
   damaging winds, along with possibly a tornado or two.  With time, as
   upscale growth of convection is expected, a
   north-northeastward-moving band or bands of storms may spread across
   portions of the western Dakotas, with continued severe risk. 
   Overnight, a cluster of storms may acquire a more eastward
   progression -- cresting the upper ridge and shifting into/across
   northern Minnesota, possibly including wind and hail risk through
   the end of the period.

   ...Florida/far southern Georgia...
   Per latest NHC forecasts, Alberto is expected to have become a
   Tropical Storm, and should be moving slowly northward across the
   eastern Gulf Sunday.  Variability amongst the models with respect to
   track and intensity of Alberto remains evident, which has direct
   influence on the spatial region within which low-level shear would
   be more likely to support enhanced risk for more strongly rotating
   cells.  As such, specificity regarding the risk area remains
   difficult to define, and therefore will introduce a large 5%/MRGL
   risk area across a large portion of Florida, and into far southern
   Georgia.  Expect future adjustments to the forecast as Alberto's
   track becomes more certain over time.

   ...MAXIMUM RISK BY HAZARD...
   Tornado:   5%     - Slight
   Wind:     15%     - Slight
   Hail:     15%     - Slight

   ..Goss.. 05/26/2018

   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z