U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 240052 
Storm Prediction Center ac 240050 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0650 PM CST Thu Nov 23 2017 

Valid 240100z - 241200z 

..no severe thunderstorm areas forecast... 

isolated thunderstorms are possible across far South Florida this 
evening and overnight. No severe weather is expected. 

..01z update... 
00z key and mfl soundings show that some modest instability remains 
across southern FL, although it is somewhat tempered by warm 
temperatures aloft in the mfl sounding. Veered low-level flow has 
reduced surface convergence across much of the region and the 
expectation is for any thunderstorms to remain across far southern 
portions of the peninsula and the Keys where forcing for ascent and 
weak surface convergence persist. Strong mid/upper level flow will 
persist across the region but muted updraft strength, due to limited 
instability, should keep the severe threat low. As such, all severe 
probabilities were removed from the outlook. 

.Mosier.. 11/24/2017 


Mesoscale Discussion

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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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