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


acus01 kwns 200411 
Storm Prediction Center ac 200409 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
1109 PM CDT Thu Oct 19 2017 

Valid 201200z - 211200z 

..no severe thunderstorm areas forecast... 

scattered thunderstorms are possible during the day on Friday over 
eastern Texas, with more isolated activity overnight into eastern 
Nebraska and Iowa. 

An amplified upper trough will move across The Rockies during the 
day, approaching the High Plains into Saturday morning. A surface 
low will deepen over south-central Canada, with a cold front 
extending southward across the Central Plains Friday night. A broad 
area of southerly low-level flow will allow dewpoints to rise into 
the low to mid 60s from the middle MO valley into Kansas and OK, and 
into the lower 70s along the Texas coast. This northward flux of 
moisture will be aided by a broad 850 mb jet, in excess of 50 kt and 
extending from Texas to Minnesota. 

Ahead of the primary upper trough will be a lead wave that will move 
from Texas and OK northeastward across the lower MO valley during the 
day. This wave will be responsible for the bulk of the storm 
activity over eastern Texas. 

..East Texas... 
Aforementioned leading shortwave trough combined with moist return 
flow will lead to a zone of thunderstorm activity mainly east of 
I-35 in Texas. This zone of lift will be on the western periphery of 
the larger scale surface high centered over the Appalachians. 
Activity is likely to be ongoing Friday morning, and will likely 
dissipate after 00z as wind fields re-adjust with the approach of 
the larger upper system. Forecast soundings show some low-level 
veering of the winds with height, but with weak magnitude. Given 
this, and relatively cool surface temperatures, it appears any 
low-end tornado threat is too minimal even for a 2 percent area, 
though storms may exhibit weak/transient rotation at times. 

..eastern NE into Iowa overnight... 
Persistent warm advection via a 50+ kt low-level jet and height 
falls into Saturday morning may be enough for isolated thunderstorm 
activity, though capping will remain a concern across much of the 
plains. Conditionally, any storm could be capable of marginally 
severe hail as temperatures aloft will be cool, but, even effective 
shear values at that time will not be particularly favorable. As 
such, potential looks to remain sub-marginal. 

.Jewell/Cook.. 10/20/2017 


Mesoscale Discussion

acus11 kwns 192021 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 192020 

Mesoscale discussion 1720 
National Weather Service Storm Prediction Center Norman OK 
0320 PM CDT Thu Oct 19 2017 

Areas affected...southwest New Mexico into a portion of far western 

Concerning...severe potential...watch unlikely 

Valid 192020z - 192245z 

Probability of watch issuance...5 percent 

Summary...stronger storms will remain capable of producing a few 
instances of downburst winds and hail through early evening. Overall 
threat is marginal, and coverage of severe events is not expected to 
become sufficient for a ww. 

Discussion...surface temperatures have climbed to near 80f with 
dewpoints in the mid to upper 40s in the presence of boundary-layer 
mixing, boosting MLCAPE to 400-800 j/kg. Storms over southern nm 
have increased in overall intensity during the last hour, and 
further increase in coverage may occur as forcing for ascent 
attendant to a progressive shortwave trough over Arizona spreads into 
western nm. No substantial increase in winds aloft is expected with 
the approach of the impulse, and vertical shear will remain weak and 
supportive of multicells. Nevertheless, the thermodynamic 
environment with steep lapse rates and inverted-v boundary layers 
will continue to promote a risk for a few instances of downburst 
winds and hail through early evening. 

.Dial.. 10/19/2017 

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


Latitude...Lon 31800602 31970707 32370817 33530845 33830682 33460584 
32500539 31800602