U.S. Severe Weather Forecast (Convective Outlook)

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Day Three

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acus03 kwns 220727 
swody3 
Storm Prediction Center ac 220726 


Day 3 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0226 am CDT Tuesday Jul 22 2014 


Valid 241200z - 251200z 


..there is a slight risk of severe thunderstorms for parts of eastern Montana and the western 
Dakotas... 


... 
Severe storms are possible over parts of the northern Great Plains 
on Thursday afternoon and evening. Strong to locally severe storms 
are also possible over parts of the Carolina Piedmont and coastal 
plain. 


... 
A vigorous shortwave trough over the Pacific northwest will impinge on the 
northern plains/Canadian prairies ridge as it reaches the Lee of the 
Canadian southern rockies early Friday. Although guidance continues to 
differ on speed...an attendant surface cold front should push across 
eastern Montana into the central Dakotas by around Thursday night. Farther east...a 
broad middle-level trough will persist across southeast Canada into the eastern 
Continental U.S.. surface cold front will push S/east across the South 
Atlantic/southeast states. Trailing portion of this front will 
slowly advance east as a warm front over the northern/Central Plains. 


..nrn plains... 
A relatively confined plume of 60s surface dew points is anticipated 
in the warm/moist sector ahead of the cold front owing to a 
low-level anticyclone over the MS valley and Midwest. With very 
steep tropospheric lapse rates...near 9 degree c/km from 700-500 
mb...potential buoyancy should become strong within this narrow 
corridor. Guidance differs on spatiotemporal details with where thunderstorm 
initiation will occur along the front on Thursday afternoon /ECMWF 
remaining farther west in eastern Mt/. The peripheral influence of The 
Rockies shortwave trough will yield wind profiles conducive to 
supercell clusters capable of severe wind/hail. The eastern extent of 
this risk Thursday evening should be limited by substantial mlcin. 


..Carolina Piedmont/coastal plain... 
Although low-level winds should remain weak...a belt of enhanced 
middle/upper-level west/swlys is expected to overlap the remaining 
pre-frontal warm sector through Thursday evening. With around 30-35 knots 
flow at 500 mb...scattered storms along the front and sea breeze may 
become semi-organized with a risk for isolated damaging winds and 
marginal hail. 


.Grams.. 07/22/2014