May 28, 2018 1630 UTC Day 1 Convective Outlook
Updated: Mon May 28 16:19:54 UTC 2018 (20180528 1630Z Day 1 shapefile | 20180528 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20180528 1630 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
ENHANCED 62,574 837,976 Fort Collins, CO...Greeley, CO...Cheyenne, WY...Laramie, WY...Garden City, KS...
SLIGHT 124,306 6,348,645 Denver, CO...Aurora, CO...Columbus, GA...Amarillo, TX...Lakewood, CO...
MARGINAL 439,231 21,959,228 Kansas City, MO...Atlanta, GA...Omaha, NE...Minneapolis, MN...St. Paul, MN...
Probabilistic Tornado Graphic
20180528 1630 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
10 % 7,018 62,743 Sterling, CO...Fort Morgan, CO...
5 % 69,849 3,999,166 Aurora, CO...Columbus, GA...Macon, GA...Greeley, CO...Albany, GA...
2 % 130,709 10,709,938 Denver, CO...Atlanta, GA...Amarillo, TX...Tallahassee, FL...Lakewood, CO...
Probabilistic Damaging Wind Graphic
20180528 1630 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 % 19,884 156,511 Garden City, KS...Liberal, KS...Guymon, OK...
15 % 136,053 4,078,471 Denver, CO...Aurora, CO...Amarillo, TX...Lakewood, CO...Fort Collins, CO...
5 % 378,278 23,911,520 Kansas City, MO...Atlanta, GA...Omaha, NE...Minneapolis, MN...St. Paul, MN...
Probabilistic Large Hail Graphic
20180528 1630 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 62,467 859,911 Fort Collins, CO...Greeley, CO...Cheyenne, WY...Laramie, WY...Garden City, KS...
30 % 62,549 862,795 Fort Collins, CO...Greeley, CO...Cheyenne, WY...Laramie, WY...Garden City, KS...
15 % 93,098 3,349,870 Denver, CO...Aurora, CO...Amarillo, TX...Lakewood, CO...Thornton, CO...
5 % 341,095 10,593,875 Colorado Springs, CO...Minneapolis, MN...St. Paul, MN...Lubbock, TX...Sioux Falls, SD...
   SPC AC 281619

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1119 AM CDT Mon May 28 2018

   Valid 281630Z - 291200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM SOUTHEAST
   WYOMING AND NORTHEAST COLORADO INTO SOUTHWEST NEBRASKA...WESTERN
   KANSAS...INTO THE TEXAS PANHANDLE...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE CENTRAL PLAINS...AND OVER PORTIONS OF GEORGIA AND EASTERN
   ALABAMA...

   ...SUMMARY...
   Severe thunderstorms with very large hail, wind damage and a few
   tornadoes are expected across parts of the Great Plains.  A few
   tornadoes will also be possible over parts of Georgia and Alabama in
   conjunction with Alberto.

   ...Central Plains...
   A persistent upper low is centered over UT, with a mid-level jet
   wrapping around the low across AZ/NM into CO/NM.  Water vapor
   imagery shows a significant shortwave trough embedded in the
   stronger flow over northeast NM.  This feature will rotate into
   central CO later this afternoon, providing the lift for an active
   severe weather event across parts of the central Plains states.

   ...CO...
   Latest visible satellite imagery and surface analysis shows a
   boundary extending from southwest NE into eastern CO.  Low clouds on
   the north side of this boundary are slowing eroding, and should
   result in a corridor of moderate CAPE later today (dewpoints in the
   upper 50s and steep mid level lapse rates).  12z CAM solutions are
   consistent in the development of thunderstorms along/north of this
   boundary from just southeast of DEN into northeast CO.  Forecast
   soundings suggest a favorable combination of thermodynamics and deep
   layer shear of 50-60 knots, supporting supercells.  Enhanced
   low-level shear will also be favorable of a few tornadoes.  Have
   introduced a small 10% tornado risk area for this threat.  Very
   large hail and damaging winds will also be possible in this area.

   ...Western KS to TX Panhandle...
   Farther east, strong heating and ample CAPE will result in a line of
   thunderstorms roughly along the CO/KS border southward into the TX
   panhandle this afternoon.  These storms will rapidly become severe,
   capable of very large hail and damaging winds.  Isolated tornadoes
   are also possible in more persistent supercells.  These storms are
   expected to merge into a broken line, with an enhanced wind damage
   threat through the evening.

   ...GA/AL...
   The center of Alberto will track across the FL Panhandle and into AL
   today.  Considerable heating is occurring to the east of the center
   across parts of GA and southeast AL, where dewpoints are in the
   low/mid 70s.  CAM guidance suggests that scattered thunderstorms
   will form in this corridor later today, with forecast soundings
   indicating sufficient low level shear/helicity for some risk of
   tornadoes in the more persistent updrafts.  Have therefore upgraded
   this area to SLGT risk.

   ..Hart/Elliott.. 05/28/2018

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