U.S. Severe Weather Forecast (Convective Outlook)

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Storm Prediction Center ac 181254 


Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0754 am CDT Tue Jun 18 2019 


Valid 181300z - 191200z 


..there is an enhanced risk of severe thunderstorms parts of 
central Kansas to West Texas... 


..there is a slight risk of severe thunderstorms parts of the 
Middle-Atlantic States... 


... 
Scattered severe thunderstorms are expected across parts of the 
central and southern Great Plains in multiple episodes this 
afternoon into tonight. 


..central and southern Great Plains... 
Below-average confidence pattern with multiple subtle mechanisms 
driving forcing for ascent, along with pockets of less-than-optimal 
boundary-layer moisture in the wake of prior convective overturning. 
The net result is that while a broad corridor of organized severe 
storms is evident, the aforementioned factors yield large variance 
in both convection-allowing and parametrized guidance. 


An mesoscale convective system is ongoing in central Texas and while not simulated well by 
convection-allowing guidance, will probably still decay by late 
morning. Showers associated with a pair of mcvs over northwest and 
southwest Kansas should persist through the day. Initial surface-based 
storm development is expected by midday across central Kansas amid a 
plume of mid 60s dew points. More intense/longer-lived updrafts are 
anticipated towards late afternoon, especially in south-central Kansas 
to north-central OK where deep-layer shear will be stronger along 
the northern periphery of the moderate buoyancy plume. This corridor 
may be most favored for discrete supercells. Mesoscale convective vortex-induced vorticity 
across northern Kansas and enlarging low-level hodographs near the Kansas/OK 
border will support a risk for tornadoes. 


Farther west, scattered thunderstorm development appears more 
probable over the Raton Mesa vicinity at peak heating as a minor 
mid-level impulse in Utah crosses the southern rockies. Amid 30-40 kt 
500-mb westerlies, this activity should spread east and impinge on 
Richer boundary-layer moisture in the eastern Texas Panhandle and 
western OK this evening. Scattered severe hail/wind and a couple 
tornadoes are possible with an mesoscale convective system potentially developing 
east-southeast across OK late tonight aided by a strengthening 
southwesterly low-level jet. 


Farther south, a couple supercells should form over the higher 
terrain of the Texas trans-Pecos with a primary risk of large hail. 
Minor mid-level height rises suggest robust mlcin will hold east of 
the Pecos River, limiting the spatial extent of this threat. A 
separate area of thunderstorms may form near the intersection of the 
dryline and residual outflow boundary trailing from the central Texas 
mesoscale convective system. A deeply mixed boundary layer should support a few supercells 
that might organize into a cluster this evening. Large hail and 
severe wind should be the primary threats. 


..mid-Atlantic states... 
An area of organized severe potential is apparent across southeast 
PA, NJ, northern MD, and Delaware ahead of an mesoscale convective vortex/weak surface cyclone 
currently over western PA. Here, some enlargement to low-level 
hodographs in conjunction with moderate boundary-layer heating of 
low 70s dew points should support a risk for a few supercells 
capable of a couple tornadoes and damaging winds. 


..central Gulf Coast to Carolinas... 
A belt of 20-30 kt west-southwesterly flow will persist amid 
afternoon MLCAPE of 1000-2000 j/kg. This should again Foster a 
threat for mainly locally damaging wind as numerous multicells occur 
through this afternoon. 


.Grams/Gleason.. 06/18/2019 


$$ 

Mesoscale Discussion


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sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 180708 
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Mesoscale discussion 1113 
National Weather Service Storm Prediction Center Norman OK 
0208 am CDT Tue Jun 18 2019 


Areas affected...portions of West Texas and far southeastern nm 


Concerning...Severe Thunderstorm Watch 393... 


Valid 180708z - 180815z 


The severe weather threat for Severe Thunderstorm Watch 393 
continues. 


Summary...mainly an isolated large hail threat persists across 
Severe Thunderstorm Watch 393, which is scheduled to expire at 08z. 
Additional watch issuance is not expected early this morning. 


Discussion...outflow has surged well southward from ongoing storms 
across far southeastern nm and West Texas based on recent radar 
imagery. Even so, a modest (25-30 kt) southeasterly low-level jet 
should continue to support elevated convection across this region 
for the next couple of hours. With generally 1000-2000 j/kg of 
MUCAPE and around 30-35 kt of effective bulk shear present, some of 
the strongest elevated cores may pose an isolated large hail threat 
in the short term. As nocturnal cooling continues across this 
region, convective inhibition should further strengthen. A gradual 
weakening trend with ongoing strong to severe storms will likely 
occur. Severe Thunderstorm Watch 393 is scheduled to expire at 08z, 
and no new watch issuance is anticipated early this morning due to 
the isolated and increasingly marginal severe threat. 


.Gleason.. 06/18/2019 


..please see www.Spc.NOAA.Gov for graphic product... 


Attention...WFO...sjt...lub...maf... 


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