U.S. Severe Weather Forecast (Sääkatsaus)

Day Three

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Storm Prediction Center ac 240553 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
1153 PM CST Wed Jan 23 2019 

Valid 241200z - 251200z 

..there is a marginal risk of severe thunderstorms over a portion 
of the Florida Peninsula and eastern North Carolina... 

Thunderstorms are likely across the Florida Peninsula later this 
morning, with a few strong to severe wind gusts and a brief tornado 
possible. A few strong storms with damaging wind the main threat 
will also be possible over eastern North Carolina later this 

..Florida Peninsula... 

A strong (50+ kt) southerly low-level jet will migrate through the 
Florida Peninsula this morning with Theta-E advection resulting in 65-67 
f dewpoints over much of central Florida by 12z. Despite this modest 
increase in low-level moisture, instability will remain marginal 
(generally below 800 j/kg) due to poor mid-level lapse rates and 
widespread clouds. A band of convection with embedded thunderstorms 
will persist along the warm conveyor belt through the peninsula 
during the morning. The kinematic environment accompanying a 
progressive upper trough moving through the southeast states will 
favor a few organized structures including embedded bowing segments 
and meso-vortices. However, tendency will be for the stronger 
forcing associated with the upper trough to move away from the Florida 
Peninsula later this morning. This along with the expected marginal 
thermodynamic environment lowers confidence in a more robust severe 
threat. Therefore will maintain the marginal risk category this 
update, mainly for isolated damaging wind and a tornado. 

..eastern North Carolina... 

A surface low will develop over the mid Atlantic states by the start 
of this period in association with the northeast-ejecting shortwave 
trough. The attendant intense (80+ kt) low level jet will develop 
through eastern NC and eastern Virginia resulting in the advection of low 
60s f near-surface dewpoints inland and modest destabilization of 
the surface layer, though widespread clouds and weak lapse rates 
should limit MLCAPE to below 500 j/kg. With the stronger forcing 
moving through the mid Atlantic region early in the period within a 
very favorable kinematic environment for organized storms, potential 
exists for a low-topped pre-frontal band of convection to intensify 
from eastern NC into eastern Virginia later this morning. This band of 
showers with a few embedded thunderstorms may pose some risk for 
mainly damaging wind gusts given 60+ kt just off the surface that 
could be transported downward within the stronger convective 
elements. Activity should move offshore by late morning. 

.Dial/squitieri.. 01/24/2019 


Mesoscale Discussion

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sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 240918 

Mesoscale discussion 0051 
National Weather Service Storm Prediction Center Norman OK 
0318 am CST Thu Jan 24 2019 

Areas affected...western Florida Peninsula 

Concerning...severe potential...watch unlikely 

Valid 240918z - 241115z 

Probability of watch issuance...20 percent 

Summary...the potential for isolated damaging winds and/or a brief 
tornado will spread into the western Florida Peninsula through the 
early morning hours. 

Discussion...a semi-continuous northeast/southwest-oriented 
convective line will continue to move inland across the west-central 
Florida Peninsula during the predawn hours, with this line featuring some 
embedded small-scale bowing segments. These storms will initially 
move into coastal areas north of Tampa Bay-St. Petersburg over the 
next hour, while not reaching The Fort Myers vicinity until 6-7 
am/11-12z or later. 

Ahead of these storms, surface temperatures and dewpoints have 
generally increased a degree or two over the past couple of hours, 
which relates to weakening boundary layer inhibition inland as 
suggested by latest Storm Prediction Center objective analysis. In concert with the 
approaching upstream upper trough, low/mid-level winds will continue 
to strengthen, with latest WSR-88D vwp data from Tampa Bay 
suggestive of around 350 m2/s2 of 0-1km srh. This will support a 
continuance of bowing segments along with the possibility of 
embedded mesovortices capable of isolated damaging winds and some 
tornado risk. While a watch is not currently anticipated, convective 
trends will continue to be monitored. 

.Guyer/Peters.. 01/24/2019 

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


Latitude...Lon 26338180 26568222 27638288 28518269 28488202 28278185 
27428167 26868158 26458154 26338180