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FXUS64 KMRX 240221

Area Forecast Discussion
National Weather Service Morristown TN
921 PM EST Sat Feb 23 2019


The main purpose for the evening update was to increase rainfall
amounts for the overnight hours and address a growing concern with
regard to the flash flood potential tonight.

Numerical guidance shows a fairly high plume of PWAT values moving
into our area from the southwest tonight, along/ahead of the cold
front that will move through by daybreak Sunday. Couple this with
sufficient forcing for convection and there is concern that
significantly higher rainfall rates will be observed overnight
tonight than what was seen earlier today. Duration will be
shorter, and totals will definitely be lower than earlier today.
But the rainfall rates are what concern me at this point. Flash
flood guidance suggests as little as half an inch in a one hour
period would be enough to start causing additional problems.
I think both the short duration rates, as well as expected 
totals, will be enough to surpass that.

Bumped up rainfall totals through the overnight hours to the 0.75
to 1.00" range for the plateau and central/southern TN Valley 
region. Have little doubt there will be some amounts that exceed
an inch or even an inch and a half. By themselves, those totals 
don't sound impressive. Given the soil conditions though, if they
occur in a 1-2 period tonight, especially for central valley
locations, some additional flash flooding would seem to be a 
given. We will continue to closely monitor the situation

I'll close on a positive note here. There are some details that 
give hope for a more favorable outcome. Cloud top temperatures on 
infrared satellite imagery are warming and lightning strike counts
seem to be coming down. Additionally the entire precip shield is 
moving along quickly. So it is possible that this event could 
conclude with no increase in flooding issues above the substantial
problems we've already had.


Chattanooga Airport, TN             51  57  34  55 /  90  20   0   0 
Knoxville McGhee Tyson Airport, TN  52  57  31  51 /  90  40   0   0 
Oak Ridge, TN                       51  56  31  52 /  90  30   0   0 
Tri Cities Airport, TN              50  57  27  48 /  80  50   0   0 


NC...Flood Watch until 7 AM EST Sunday for Cherokee-Clay.

TN...High Wind Warning until 7 AM EST Sunday for Blount Smoky 
     Mountains-Cocke Smoky Mountains-Sevier Smoky Mountains.

     Flood Watch until 7 AM EST /6 AM CST/ Sunday for Anderson-
     Bledsoe-Blount Smoky Mountains-Bradley-Campbell-Claiborne-
     Cocke Smoky Mountains-East Polk-Grainger-Hamblen-Hamilton-
     Meigs-Morgan-NW Blount-North Sevier-Northwest Carter-
     Northwest Cocke-Northwest Greene-Northwest Monroe-Rhea-
     Roane-Scott TN-Sequatchie-Sevier Smoky Mountains-Southeast 
     Carter-Southeast Greene-Southeast Monroe-Sullivan-Unicoi-
     Union-Washington TN-West Polk.

     Wind Advisory from 7 AM to 7 PM EST Sunday for Blount Smoky 
     Mountains-Cocke Smoky Mountains-Sevier Smoky Mountains.

     Wind Advisory until 7 PM EST Sunday for Johnson-Southeast Carter-
     Southeast Greene-Southeast Monroe-Unicoi.

VA...Flood Watch until 7 AM EST Sunday for Lee-Russell-Scott-

     Wind Advisory from 7 AM to 7 PM EST Sunday for Russell-


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