May 30, 2018 0600 UTC Day 1 Convective Outlook
Updated: Wed May 30 05:52:12 UTC 2018 (20180530 1200Z Day 1 shapefile | 20180530 1200Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20180530 1200 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 92,712 1,049,492 Idaho Falls, ID...Pocatello, ID...Enid, OK...Twin Falls, ID...Bozeman, MT...
MARGINAL 258,031 28,315,408 Detroit, MI...Indianapolis, IN...Columbus, OH...Denver, CO...Oklahoma City, OK...
Probabilistic Tornado Graphic
20180530 1200 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 % 23,867 184,500 Liberal, KS...Elk City, OK...Guymon, OK...Weatherford, OK...Clinton, OK...
2 % 177,267 27,637,902 Detroit, MI...Indianapolis, IN...Columbus, OH...Denver, CO...Oklahoma City, OK...
Probabilistic Damaging Wind Graphic
20180530 1200 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
15 % 87,084 1,011,178 Idaho Falls, ID...Pocatello, ID...Enid, OK...Twin Falls, ID...Bozeman, MT...
5 % 258,765 27,706,967 Detroit, MI...Indianapolis, IN...Columbus, OH...Denver, CO...Oklahoma City, OK...
Probabilistic Large Hail Graphic
20180530 1200 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
15 % 89,520 990,981 Idaho Falls, ID...Pocatello, ID...Twin Falls, ID...Bozeman, MT...Rexburg, ID...
5 % 180,228 7,947,774 Denver, CO...Oklahoma City, OK...Tulsa, OK...Colorado Springs, CO...Wichita, KS...
   SPC AC 300552

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1252 AM CDT Wed May 30 2018

   Valid 301200Z - 311200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE TX/OK
   PANHANDLES INTO WESTERN OK AND FROM SOUTHERN ID INTO CENTRAL MT...

   ...SUMMARY...
   Severe thunderstorms are possible over parts of Idaho and Montana as
   well as over parts of the southern Plains this afternoon and
   evening.

   ...Synopsis...
   Upper low currently over the western Dakotas is expected to open up
   as it slowly tracks northeastward into northern MN. At the same
   time, remnants of Alberto will move into the lower OH Valley,
   phasing with northern shortwave trough and moving through lower MI
   during the second half of the period. A surface trough will extend
   between the two surface lows associated with these features.
   Numerous thunderstorms are expected along and east of this surface
   trough with widespread thunderstorms also anticipated amidst the
   very moist airmass in place across the TN Valley, Mid-Atlantic, and
   Southeast.

   Despite a second consecutive evening/night of thunderstorms across
   the Plains on Tuesday, a fairly moist airmass will remain over the
   Plains with upper 60s dewpoints anticipated as far north as the
   KS/OK border. Strong daytime heating will promote the deepening of a
   surface low across the TX South Plains with at least mid 60s
   dewpoints wrapping around its northern periphery across the TX and
   OK Panhandles. Thunderstorms will likely develop within the upslope
   flow across far southeast CO with potential upscale growth into a
   linear MCS as it progresses eastward across the TX/OK Panhandles and
   into western OK.

   Farther west, a deep shortwave trough will gradually move across the
   Pacific Northwest and into the northern Rockies, providing the
   impetus for thunderstorm development within the modest unstable
   airmass over the northern Great Basin and northern Rockies.

   ...Central/Southern High Plains into the southern Plains...
   A surface low will deepen across the TX South Plains with
   easterly/southeasterly upslope flow anticipated around its northern
   periphery into southeast CO. Destabilization promoted by this moist
   upslope flow coupled with modest forcing for ascent provided by a
   low-amplitude shortwave trough (currently moving into southern AZ)
   will result in convective development across southeast CO during the
   afternoon. High-based nature of this initial development will favor
   strong outflow and a relatively quick linear transition. Corridor of
   low-level moisture and instability favors eastward progression of
   these storms across the TX/OK Panhandles and into western OK. A
   strengthening low-level jet and more favorable moisture across
   western OK will likely promote the persistence and perhaps growth of
   the linear MCS as it moves across the area during the evening. 

   Primary severe threat is initially anticipated to be large hail with
   a transition to strong wind gusts with eastward progress. There is
   some question as to how far east the severe threat extends given the
   expectation for nocturnal destabilization and resulting elevated
   character of the convection as it enters central OK. Large
   temperature-dewpoint spreads will temper the overall tornado threat,
   although some increase in tornado potential is anticipated with
   eastern extent as low-level moisture increases and
   temperature-dewpoint spreads decrease.

   ...OH Valley/Lower MI...
   A very moist airmass is anticipated across the region as the
   remnants of Alberto move into lower MI. PW values will likely top 2
   inches, which is near all-time records based on SPC climatology.
   Resulting very moist profiles are characterized by weak lapse rates
   and only modest instability. That being said, low-level wind
   profiles remain favorable for low-level rotation with any more
   persistent updrafts and a tornado or two cannot be completely ruled
   out. Primary severe threat across the area appears to be damaging
   downburst winds resulting from water-loaded downdrafts.

   ...Northeast NV across southern ID into central MT...
   Cool temperatures aloft, strong daytime heating, and increasing
   mid-level moisture will result in airmass destabilization across the
   region with scattered thunderstorms anticipated during the
   afternoon. Strengthening mid-level flow ahead of the approaching
   shortwave trough will support bowing line segments capable of strong
   wind gusts with some hail also possible in the strongest updrafts.

   ..Mosier/Wendt/Gleason.. 05/30/2018

   CLICK TO GET WUUS01 PTSDY1 PRODUCT

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