May 6, 2018 1630 UTC Day 1 Convective Outlook
Updated: Sun May 6 16:29:30 UTC 2018 (20180506 1630Z Day 1 shapefile | 20180506 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20180506 1630 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 9,177 2,389,523 Raleigh, NC...Durham, NC...Cary, NC...Greenville, NC...Rocky Mount, NC...
MARGINAL 130,381 5,097,121 Greensboro, NC...Springfield, MO...Fayetteville, NC...High Point, NC...Suffolk, VA...
Probabilistic Tornado Graphic
20180506 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
No Risk Areas Forecast
Probabilistic Damaging Wind Graphic
20180506 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
5 % 135,022 6,522,313 Raleigh, NC...Durham, NC...Springfield, MO...Fayetteville, NC...Cary, NC...
Probabilistic Large Hail Graphic
20180506 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
15 % 9,167 2,398,730 Raleigh, NC...Durham, NC...Cary, NC...Greenville, NC...Rocky Mount, NC...
5 % 125,685 4,875,185 Greensboro, NC...Springfield, MO...Fayetteville, NC...High Point, NC...Jacksonville, NC...
   SPC AC 061629

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1129 AM CDT Sun May 06 2018

   Valid 061630Z - 071200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER A PORTION OF
   EASTERN NC...

   ...SUMMARY...
   Isolated severe storms with hail and wind are possible late
   afternoon to mid-evening over central/eastern North Carolina and far
   southeast Virginia, the interior Northwest and northern Rockies, as
   well as southern Missouri and northern Arkansas.

   ...Central/eastern NC and far southeast VA...
   A shortwave trough over the central Appalachians will decay as it
   progresses towards the Northeast states. A weak surface cyclone near
   Greensboro should track east along the NC/VA border through this
   evening. A narrow wedge of robust insolation is underway near the
   surface cyclone, between the impinging cold front and widespread
   cloud/stratiform rain across eastern portions of NC/VA. Weak
   mid-level lapse rates sampled by 12Z soundings will limit updraft
   acceleration this afternoon, but the corridor of surface heating
   amid residual mid 60s surface dew points should yield MLCAPE of
   500-1000 J/kg. Isolated to scattered storm development is likely by
   mid-late afternoon. J-shaped hodographs will favor strong vertical
   shear within the mid to upper portion of the thermodynamic profile
   which should support a few supercells. Isolated to widely scattered
   severe hail and damaging wind gusts will be possible, before
   weakening after sunset.

   ...Southern MO/northern AR...
   A series of subtle mid-upper speed maxima will move from the central
   Great Plains to the Lower MS Valley atop a diffuse confluence
   boundary that should sag into central OK to southern MO. Though
   boundary-layer moisture is marginal, surface dew points in the lower
   50s in conjunction with strong surface heating will promote
   inverted-v thermodynamic profiles. Steep lapse rates above the
   inverted-v will contribute to MLCAPE from 500-1000 J/kg in the late
   afternoon. Isolated high-based storms should form by early evening
   and likely evolve into a small multicell cluster or two given
   effective shear of 20-30 kt. Isolated severe hail and damaging wind
   gusts will be the main hazards, before storms diminish after sunset.

   ...Interior Northwest/Northern Rockies...
   A compact shortwave trough over the northern Sierra Nevada will
   dampen as it reaches the northern Rockies tonight. Large-scale
   ascent accompanying this feature will foster storm development from
   eastern OR into western ID during the late afternoon. Though
   low-level moisture will be limited, rather steep low to mid-level
   lapse rates will support MLCAPE around 500 J/kg at peak heating.
   Multicell clusters are expected to develop/spread northeast across
   northern ID into western MT through mid-evening. Isolated severe
   wind gusts, as well as marginally severe hail will be possible until
   storms weaken by late evening.

   ..Grams/Gleason.. 05/06/2018

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