U.S. Severe Weather Forecast (Конвекција-преглед)

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Storm Prediction Center ac 231252 


Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0752 am CDT Wed may 23 2018 


Valid 231300z - 241200z 


..there is a slight risk of severe thunderstorms across the 
north-Central High plains... 


... 
Isolated severe thunderstorms are possible this afternoon and 
evening across the High Plains and eastern portions of 
Virginia/North Carolina. 


..northern plains... 
An upper low over the Great Basin/central rockies will continue to 
move northeastward toward the northern rockies and adjacent High 
Plains through the afternoon and tonight. Lee cyclogenesis across 
the north-Central High plains will influence a northward increase in 
low-level moisture (50s to some 60s f surface dewpoints) in the warm 
sector to the south of a northward-shifting warm front and to the 
east of the Lee trough. Beneath a northeastward-advecting elevated 
mixed layer (eml), this moisture will support moderate 
destabilization with as much as 1000-2500 j/kg MLCAPE from western 
Nebraska and far eastern portions of Wyoming and Colorado northward 
into far eastern Montana and portions of the Dakotas. 


An eroding cap/orographic influences will result in isolated to 
scattered surface-based thunderstorm development initially along the 
Front Range vicinities potentially spanning northern Colorado, 
eastern Wyoming into southeast Montana. On the periphery of the 
previously described upper low, it also appears that a subtle 
peripheral disturbance/speed Max, located near The Four Corners area 
this morning, may be favorably timed to arrive into the region 
around peak heating, with further influences on forcing for ascent, 
increasing vertical shear etc. 


The potential for organized storms appears greatest over parts of 
the north-Central High plains where vertical shear is forecast to be 
strongest. Various models imply a higher storm coverage and severe 
potential from far eastern Wyoming northeastward into western 
Nebraska and the Black Hills vicinity, with the possibility that 
storms will grow upscale and spread northeastward across South 
Dakota/northern Nebraska this evening with the aid of a 
strengthening low-level jet. Bouts of large hail and damaging winds 
will be the primary risks. 


..eastern New Mexico/southern High Plains... 
Another day of widely scattered thunderstorm development is expected 
across the region later today as moist low-level upslope flow 
persists across the region. 12z regional radiosonde observations from Amarillo, 
Midland, and del Rio, Texas all sampled precipitable water values 
that are in the upper 20% of daily climatological norms. Mid-level 
winds will continue to weaken today as heights also rise, but 
aforementioned upslope and orographic lift/differential heating will 
lead to widely scattered strong to severe thunderstorms this 
afternoon in the presence of steep lapse rates and ample buoyancy in 
excess of 2000+ j/kg MLCAPE. Scenario favors some multicells or at 
least pulse-type storms capable of large hail across eastern New 
Mexico and far west/southwest Texas. Congealing outflows and a 
modestly increasing southerly low-level jet could yield one or more 
small-scale complexes that move eastward into west/northwest Texas 
during the evening and overnight, which would include the lingering 
possibility of severe-caliber wind gusts on a localized basis. 


..Virginia/North Carolina... 
A cold front will progress southeastward across the region through 
the afternoon and evening. Temperatures ahead of the front will 
likely reach the mid-80s coincident with surface dewpoints in the 
upper 60s f, which is supportive of air mass destabilization and 
moderate buoyancy with as much as 1500-2000 j/kg MLCAPE this 
afternoon. Deep-layer shear is forecast to favor multicells with 
some upscale growth into southeastward-moving segments expected. 
Isolated damaging wind gusts should be the most likely hazard, 
although some hail could occur as well. 


... 
A weak cold front will continue to spread southeastward across Maine 
today before clearing the coast by late afternoon/early evening. It 
appears that a pocket of relatively steep mid-level lapse rates, as 
partially sampled by the maniwaki Quebec 12z observed sounding, will 
accompany an amplifying/southeastward digging shortwave trough and 
speed Max located over northern Quebec this morning. Although the 
boundary layer will not be overly moist near and ahead of the front, 
steepening low/mid-level lapse rates in the presence of increasing 
dynamic forcing for ascent will be favorable for diurnally 
increasing thunderstorms. Relatively well-mixed boundary layer 
profiles coupled with strengthening westerly mid-level winds could 
yield some thunderstorms that are capable of locally damaging wind 
gusts along with small hail. 


.Guyer/Goss.. 05/23/2018 


$$ 

Mesoscale Discussion


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Storm Prediction Center mesoscale discussion 222324 
vaz000-mdz000-230100- 


Mesoscale discussion 0496 
National Weather Service Storm Prediction Center Norman OK 
0624 PM CDT Tue may 22 2018 


Areas affected...southern Maryland and southeast Virginia 


Concerning...Severe Thunderstorm Watch 116... 


Valid 222324z - 230100z 


The severe weather threat for Severe Thunderstorm Watch 116 
continues. 


Summary...locally strong wind gusts cannot be ruled out, though the 
overall severe-weather threat across the remainder of ww 116 is 
expected to undergo a further diminishing trend. 


Discussion...at 2315z, mosaic radar imagery showed a line of storms 
extending from Dorchester County, Maryland into far southern Maryland (st. 
Mary's county) and far southeast Virginia (james city county), with this 
line moving east at 25 kt. The environment immediately downstream 
is gradually stabilizing per objective analyses, while stronger 
shear that would support organized storms is located north of these 
storms in northern Maryland to Delaware. Given the slow storm motion, 
unfavorable thermodynamics and kinematics, and the onset of diabatic 
cooling stabilizing the boundary layer, parts or most of the 
remainder of ww 116 could be canceled early. 


.Peters.. 05/22/2018 


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


Attention...WFO...phi...akq...lwx... 


Latitude...Lon 37287795 37927705 38717661 38637609 37887599 37307627 
37177671 37227740 37287795