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.
Oklahoma City, OK...Virginia Beach, VA...Miami, FL...Raleigh, NC...Norfolk, VA...
SPC AC 052302
Day 1 Convective Outlook AMEND 1
NWS Storm Prediction Center Norman OK
0602 PM CDT Sun May 05 2019
Valid 052300Z - 061200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM WEST TEXAS
INTO SOUTHEAST NEBRASKA...INCLUDING MUCH OF KANSAS AND WESTERN
AMENDED TO ADD MORE OF OK AND KS IN SLIGHT RISK
Widely scattered severe storms capable of large hail and damaging
winds are most probable from west Texas into eastern Nebraska, and
possibly expanding across much of western Oklahoma this evening.
Expanded Slight Risk for significant hail and damaging winds
eastward across more of Kansas, western Oklahoma, and northwest
...20Z Outlook Update...
Severe probabilities were reduced in portions of Virginia, North
Carolina, and Florida to the west of deeper convection in those
areas. Storms (especially in Florida) continue to shift eastward
toward open Atlantic waters and are leaving relatively stable
conditions in their wake.
Farther west, severe probabilities across northwestern/north-central
Kansas (near Russell and Hill City) were increased. Latest CAMs
indicate mature convection traversing these areas, and very steep
mid-level lapse rates will support a risk of hail with stronger
cores. Latest satellite and lightning imagery suggests early-stage
development upstream of these areas (northwestern Kansas) and these
trends may continue through the afternoon. Ref MCD 541 for
short-term convective trends in western Kansas.
.PREV DISCUSSION... /ISSUED 1150 AM CDT Sun May 05 2019/
...Southern/central High Plains...
Isolated/widely scattered supercells capable of large hail and
eventually damaging winds, and possibly some tornado risk, are
expected across a broad north-south expanse of central/southern High
Plains. These storms are expected to develop near the dryline late
this afternoon and east-southeastward into a moistening boundary
layer. Moist advection east of the dryline, combined with diurnal
heating and very steep mid-level lapse rates, should contribute to
preconvective MLCAPE in the 2000-3000 J/kg range, amidst 40-50 kt
effective-shear. Significant/2-inch+ hail may occur from the most
intense cores. As the low-level jet increases early this evening and
LCLs lower, some tornado risk may exist, particularly across the
Caprock vicinity of northwest Texas.
...NE/IA and vicinity...
Widely scattered to scattered thunderstorms are expected along/ahead
of the southeastward-spreading surface cold front this afternoon
into early evening, offering damaging to severe gusts and sporadic
large hail. Surface heating, near a moist axis characterized by 50s
F surface dew points, should remove MLCINH and boost buoyancy to
values favorable for strong-severe convection. Forecast soundings
suggest peak preconvective MLCAPE ranging from 1500-2000 J/kg over
southern NE to around 1000-1500 J/kg in central IA, with the
corridor of supportive MLCAPE becoming weaker/narrower from there
into WI. Low-level winds are forecast to remain weak, but clusters
or bands of convection may organize and shift southeastward away
from the frontal zone with time.
Widely scattered to scattered thunderstorms are expected this
afternoon, with damaging gusts and sporadic hail possible. The
tornado threat appears more marginal/conditional, given the lack of
enlarged low-level hodographs amidst nearly unidirectional wind
profiles; however storm-scale/boundary interactions and slightly
backed surface flow just ahead of the low may support one from a
supercell taking advantage of favorable boundary interactions.
Aided by a shortwave trough and right-entrance region of a
cyclonically curved jet segment, sufficient strength/duration of
surface heating should occur to virtually eliminate MLCINH,
fostering steep boundary-layer lapse rates and around 1000-1500 J/kg
MLCAPE. 40-50 kt effective-shear magnitudes should be common,
supporting some supercell potential.
...Florida to coastal Mid-Atlantic States...
See Mesoscale Discussion 538 for short-term details regarding the
severe risk across northern Florida, with locally damaging winds the
main severe risk. South of the ongoing midday squall line/bowing
complex across northern Florida, additional severe storms are
expected across the central Peninsula.
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