East Tennessee Weather II

#2,326
#2,326
Not liking the way the models are trending at all.

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Everyone needs to pray that this doesn't happen, especially with everything else going on in our country.
 
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#2,327
#2,327
Matt2496 said:
Not liking the way the models are trending at all.

595d4448a250d6f723744025ec5dd270.gif


Everyone needs to pray that this doesn't happen, especially with everything else going on in our country.
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Praying it’s not too bad and the worst at stays out of East TN. What is it looking like Knoxville northeastward?
 
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#2,328
#2,328
NWS in Morristown does not paint a pretty picture for southeast TN on Sunday.

Next the severe weather: Questions remain how far N the surface warm front will lift Sunday evening. There is agreement that it at least reaches the southern plateau/southern valley by 00Z before surging N immediately ahead of the cold front closer to 06Z. How much of the CWA can get into the warm sector will be key to how widespread the tornado threat can be. The southern plateau and southern valley continues to have the greatest tornado risk with at least a few hundred joules of surface based CAPE developing after 00Z behind the surface warm front. Shear in the vicinity of this boundary will be extreme with 0-1 Km SRH of 600-800+ m2/s2, 0-1 Km shear of 50+ kts, and 0-6 Km shear of 80-100 kts per latest NAM forecast soundings for CHA. As would be expected in this environment, hodographs are sickle shaped. It will not take much surface CAPE, combined with projected low LCL heights, to see tornadoes in this environment. A couple of strong, long track tornadoes will also be possible, especially in discrete cells that can form ahead of the main line and cross over
the warm front. The current SPC day 3 outlook has an enhanced risk across the the S plateau through SE TN, but would not be surprised to see this upgraded to moderate. With questions remaining how far N the surface warm front can move Sunday evening, the tornado threat appears much less at this time from the N plateau through NE TN and SW VA, however widespread damaging winds and pockets of large hail will occur with the strongest cells as the QLCS crosses. As mentioned earlier, rough timing of all this is 00-06Z, so brought pops back to categorical before tapering off from W to E after 06Z.
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#2,330
#2,330
Vol knight said:
I’m waiting until tomorrow to post my outlook for Easter. There’s still a good deal of uncertainty with the system.
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Hopefully this trends the other way tomorrow. It’s rare for the Morristown office to use that type of wording this far out.
 
#2,333
#2,333
This morning’s Morristown discussion on the severe threat.

Supercells are expected to form across MS/AL Sunday afternoon, with the steering flow taking them NE toward our area. Strong upper divergence due to jet exit/entrance region coupling will allow these storms to maintain their intensity into the evening. In addition, the surface warm front will be lifting north, allowing for convection to become surface-based. One uncertainty with this event continues to be how far north that front will lift, which will impact the northward extent of the tornado threat for our area. The SPC Day 2 Outlook has expanded the Enhanced risk area northward, which reflects the NAM`s trend of a more northward warm front. Near and south of this front, which stretches from the northern Plateau to SW NC, the NAM shows a favorable environment for supercells, which overlaps with the strongest forcing aloft in the 03-06Z time frame. Based on the 0-1 km SRH, LCL heights, 0-3 km CAPE, and STP values from the NAM across the Plateau and southern Valley, and the favorable jet coupling aloft, this event has the potential to pose the most significant tornado threat we have had since April 27, 2011. While the tornado threat is expected to be lower to the north of the warm front, there will still be a threat of damaging straight-line winds as a QLCS is expected to cross the area overnight along a pre-frontal trough after 06Z. Heavy rain Sunday night may also create flooding problems and bring river levels close to flood stage. Rain amounts for the Sunday-Sunday night period are expected
to be 1.5-3.5 inch range for most spots. A Flood Watch may be needed as we get closer to the event.
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#2,335
#2,335
I know I said I would post my outlook today, but I need to see tonight’s model runs and what the SPC’s first Day 1 Outlook will be. There’s still a great deal of uncertainty.
 
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#2,336
#2,336
Vol knight said:
I know I said I would post my outlook today, but I need to see tonight’s model runs and what the SPC’s first Day 1 Outlook will be. There’s still a great deal of uncertainty.
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I don't blame you. The models are all over the place right now.
 
#2,339
#2,339
Nonetheless


HAVE A PLAN; This have all the potential to be a severe outbreak and more than likely will be. Buy water, charge your phone, have shoes ready, Let family members know your whereabouts and HAVE A SAFE PLACE.

BUY A NOAA RADIO; You can program them to be ever so quite until a alert goes off for your county. Wouldn’t hurt to put alerts to surrounding counties to give yourself enough time to be alerted. They are around $20 bucks and that’s relatively cheap compared to a family members life.
 
#2,341
#2,341
National Weather Service Morristown TN
733 PM EDT Sat Apr 11 2020

.UPDATE...
FOR 00Z AVIATION.

&&

.SHORT TERM (Tonight through Sunday Night)...

Easter Sunday will feature a significant severe weather outbreak
across much of the deep south, possibly affecting portions of
eastern Tennessee as well. The short term discussion will focus on
this.

A closed low over southern California and the Baja region this
afternoon, will shift east into Texas before transitioning to a
negatively tilted shortwave and lifting northeast across the
Arklamiss, middle Tennessee, and the Ohio River Valley Sunday and
Sunday night. Some phasing with northern stream energy will occur
during the day tomorrow, resulting in low pressure developing over
the Arklatex region before rapidly deepening and shifting north
towards the Great Lakes. Ahead of this system, a warm front
currently resides across the central GOMEX, with surface high
pressure east of the Appalachians. This warm front will surge north
tomorrow as wind fields strengthen across the deep south in response
to rapidly strengthening low pressure to our west, making it into
the TN valley sometime during the evening hours tomorrow. How far
north into the valley, and how quickly it gets there, will likely
play key factors in the amount of severe storms we see in our
forecast area. There remain some notable uncertainties, but if
things develop in favor of severe storms there could be some
significant severe weather in our area. In addition

Regarding severe storms.

By daybreak or very shortly thereafter, elevated showers with some
embedded thunder will be spreading into the forecast area from
the southwest. Showers will continue through much of the day
thereafter, with strong to severe thunderstorms likely to move in
from the southwest during the evening hours as better forcing
arrives and storms become more surface-based. Significant
uncertainties remain with regard to how far north the warm frontal
boundary makes it. Some models move the warm front northward into
the southern TN valley around/after 00z, perhaps as far north
Crossville southeast to Athens area. If this occurs, the southern
plateau as well as the southern TN Valley will be in the warm
sector and there will be a significant tornado risk, with 0-1km
SRH values in excess of 500 m2/s2 and some surface based
instability approaching 1,000 J/kg. On the other end of the
spectrum is the case where the warm front stops in northern
Alabama. In this case, convection in our forecast area would be
more elevated, lending itself to perhaps some limited damaging
wind threat in the case of the strongest storms. At this point
more guidance supports the warm front lifting into the TN valley,
which yields an enhanced damaging winds and perhaps tornado threat
in the south. With regards to hail tomorrow, all of the forecast
soundings seems to show little in the way of deep positive CAPE
profiles, with meager mid level lapse rates to go along with it.
As such, do not think the hail threat is all that great. Certainly
sustained, rotating updrafts may be able to generate some severe
sized hail, but think this will be the exception rather than the
rule.

Discrete warm sector convection in the evening would be quickly
followed by a QLCS convective mode closer to midnight as a squall
line approaches from the west. This will likely present the best
widespread wind threat of the event.
 
#2,343
#2,343
I think even now there's still a lot of uncertainty. The rain and cloud cover earlier in the day tomorrow could hamper severe weather development (at least the tornado risk). Very curious to see what the SPC outlook later tonight shows.
 
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#2,344
#2,344
Matt2496 said:
I think even now there's still a lot of uncertainty. The rain and cloud cover earlier in the day tomorrow could hamper severe weather development (at least the tornado risk). Very curious to see what the SPC outlook later tonight shows.
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With that, it’ll depend on if the warm front moves into East TN or not. Another think to keep an eye on is will there be a line of storms in the gulf states. If there is, that’ll cut off moisture and instability.
 
#2,345
#2,345
Here’s an interesting fact for everyone. Tornadoes actually have different classifications from the NWS, and I’m not talking about the Fujita Scale. F0 and F1 tornadoes are simply called tornadoes. F2 and F3 are called strong tornadoes. F4 and F5 are called violent tornadoes.
 
#2,346
#2,346
Vol knight said:
Here’s an interesting fact for everyone. Tornadoes actually have different classifications from the NWS, and I’m not talking about the Fujita Scale. F0 and F1 tornadoes are simply called tornadoes. F2 and F3 are called strong tornadoes. F4 and F5 are called violent tornadoes.
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If you ever see “violent tornadoes” in a mesoscale outlook, it’s always a bad sign.
 
#2,348
#2,348
Vol knight said:
This. Typically, you’ll only see that wording in an area that is under a high risk.
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I can probably count on one hand how many times I’ve seen that written in an outlook. One was the super outbreak in 2011, another was the April 7, 2006 outbreak that wasn’t as bad as anticipated.
 
#2,349
#2,349
~Severe Weather Alert~

There is an enhanced risk for strong to severe thunderstorms in the Plateau and the Southern Valley. Slight Risk everywhere else in East TN.

Timing:

First round of severe weather will arrive sometime between 4 and 10 PM. The main line will come through between 1 and 4 am Monday.

Hazards:

Damaging winds up to 70 mph
Localized Flash Flooding is likely
A few tornadoes are possible, especially south of Interstate 40.

VK’s thoughts:

Honestly, this is a very difficult system to forecast for us. The severe threat is mostly based on whether the warm front is able to reach our area or if it stays in Alabama this evening. The former could increase the threat if it goes north of us, while the threat will decrease with the latter. The only thing I’m quite confident on is that there’s going to be a good bit of flash flooding today, as we could see 2-4+ inches of rain today. The best approach to take today is to prepare for the worst and hope for the best.
 
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