U.S. Severe Weather Forecast (Convective Outlook)

Day Three

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Storm Prediction Center ac 241948 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0148 PM CST Fri Nov 24 2017 

Valid 242000z - 251200z 

..no thunderstorm areas forecast... 

the risk for thunderstorms is negligible across the contiguous U.S. 
Today and tonight. 

No changes are made to the outlook for this issuance. 

.Broyles.. 11/24/2017 

Previous discussion... /issued 0948 am CST Fri Nov 24 2017/ 

..South Florida... 
While thermodynamic profiles will remain conditionally supportive of 
thunderstorm development before late afternoon, surface winds have 
become increasingly veered late this morning to the west-northwest. 
12z guidance suggests little to no convective development amid 
minimal low-level convergence. 700-600 mb temperatures will warm 
towards evening as the shortwave impulse off the space coast moves 
farther east over the Gulf Stream. 

..central Minnesota to Upper Michigan... 
Scant elevated buoyancy with pockets of MUCAPE approaching 100 j/kg 
might support a brief thunderstorm. The combination of paltry 
buoyancy and moderate frontogenetic forcing for ascent appears 
insufficient to warrant delineating an area for 10 percent or 
greater thunderstorm coverage. 


Mesoscale Discussion

acus11 kwns 231824 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 231823 

Mesoscale discussion 1776 
National Weather Service Storm Prediction Center Norman OK 
1223 PM CST Thu Nov 23 2017 

Areas affected...central Florida 

Concerning...severe potential...watch unlikely 

Valid 231823z - 232030z 

Probability of watch issuance...20 percent 

Summary...threat for a couple of damaging wind events and a brief 
tornado will persist through mid afternoon, primarily in a narrow 
corridor across north central Florida. Overall threat appears too 
marginal for a ww. 

Discussion...storms have undergone some intensification as they 
moved onshore just north of Tampa, possibly due to interaction of 
attendant NE-SW oriented convergence boundary with the seabreeze. 
Stationary front extends from just north of Tampa to north of 
Melbourne, and visible imagery shows thinning cirrus, allowing 
modest diabatic warming of the boundary layer in the warm sector 
where MLCAPE ranges from 500 to 800 j/kg over central Florida. Models 
indicate there should be some tendency for low-level winds to veer 
and weaken as a low-amplitude shortwave trough moves east of the 
peninsula later this afternoon. In the meantime, the more favorable 
low-level hodographs with 150-250 storm-relative helicity will 
persist in vicinity of the stationary front. Storms moving east and 
interacting with this boundary may develop occasional supercell 
structures and bowing segments, posing a risk for locally strong to 
damaging wind gusts and a brief tornado. The marginal thermodynamic 
environment and tendency for the low-level winds to veer and weaken 
later this afternoon suggest overall threat should remain limited. 

.Dial/Hart.. 11/23/2017 

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


Latitude...Lon 28538243 28818191 29178131 29198101 29008096 28628148 
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