Severe WX Severe Weather Event 3/28/17-3/31/17

[TWBot]

MD 0373 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR PORTIONS OF SOUTHEASTERN MISSOURI

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Mesoscale Discussion 0373
NWS Storm Prediction Center Norman OK
0752 PM CDT Wed Mar 29 2017

Areas affected...PORTIONS OF SOUTHEASTERN MISSOURI

Concerning...Severe potential...Watch likely

Valid 300052Z - 300145Z

Probability of Watch Issuance...80 percent

SUMMARY...Strong to occasionally severe thunderstorms should spread
into the discussion area over the next few hours, with an attendant
threat for a few damaging wind gusts, a couple tornadoes, and
occasional instances of severe hail.

DISCUSSION...As large-scale ascent related to the upper-level jet
continues to spread across the region, thunderstorms have increased
in coverage across portions of northern Arkansas and
southern/central Missouri. These storms are reaching the eastern
extent of ongoing Watch 99 at present. While the moist unstable
sector does not extend much beyond the eastern edge of the ongoing
watch, a corridor of favorably backed surface flow and dew points in
the upper 50s/lower 60s does exist across southeastern Missouri. As
such, veering winds with height and sufficient buoyancy will support
some severe threat east of the current watch, and watch issuance is
likely within the next hour or so.

..Picca/Edwards.. 03/30/2017

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...PAH...MEG...LSX...SGF...

LAT...LON 36799100 38019156 38219175 38479231 38739164 38609107
38069022 36938987 36589000 36539074 36799100


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[TWBot]

MD 0374 CONCERNING TORNADO WATCH 100...102...99... FOR PORTIONS OF NORTHERN ARKANSAS AND SOUTHERN/EASTERN MISSOURI

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Mesoscale Discussion 0374
NWS Storm Prediction Center Norman OK
0944 PM CDT Wed Mar 29 2017

Areas affected...PORTIONS OF NORTHERN ARKANSAS AND SOUTHERN/EASTERN
MISSOURI

Concerning...Tornado Watch 100...102...99...

Valid 300244Z - 300415Z

The severe weather threat for Tornado Watch 100, 102, 99 continues.

SUMMARY...Clusters of strong to occasionally severe thunderstorms
will persist for the next couple of hours across the region, with a
threat for damaging-wind gusts, a few instances of severe hail, and
a tornado or two.

DISCUSSION...Thunderstorms have evolved into a mix of several
clusters and semi-discrete cells embedded within stratiform
precipitation this evening. Fostered by convergence along the
western edge of a southerly low-level jet, this broad area of
convection continues to spread northeast. While they will encounter
an increasingly narrow and less buoyant warm/moist sector south of a
warm front close to the Mississippi River, some opportunity still
exists for all severe hazards this evening. With this weak, yet
sufficient low-level buoyancy present, effective storm-relative
helicity around 200-300 m2/s2 remains favorable for low-level
mesocylogenesis. Indeed, recent KSGF data has depicted
brief/occasional tightening of rotation with cells over Texas and
Powell counties.

While some potential exists for cells currently near/north of Little
Rock to track into northeast Arkansas (outside of the current
watch), buoyancy will likely remain too limited for an organized
severe potential. Nonetheless, convective trends will be monitored
as cells approach this corridor.

..Picca.. 03/30/2017

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...PAH...MEG...LSX...LZK...SGF...

LAT...LON 36939045 36049114 34749201 34649241 34869261 37119233
38639249 39099237 38779047 37889011 36939045


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[TWBot]

MD 0375 CONCERNING TORNADO WATCH 101... FOR PORTIONS OF WESTERN MS...LA...SOUTHEAST AR

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Mesoscale Discussion 0375
NWS Storm Prediction Center Norman OK
0958 PM CDT Wed Mar 29 2017

Areas affected...Portions of western MS...LA...southeast AR

Concerning...Tornado Watch 101...

Valid 300258Z - 300430Z

The severe weather threat for Tornado Watch 101 continues.

SUMMARY...The severe risk continues across Tornado Watch 101.

DISCUSSION...Clusters of deeper convection persist along the eastern
and southern fringes of a loosely organized MCS from the ArkLaMiss
to southern LA, with the most robust convection confined to southern
LA. Observational trends suggest low-level moistening east of this
activity, with surface dewpoints into the middle 60s extending
northward to the Interstate 20 corridor. This suggests that more
buoyant inflow may continue extending northward, allowing southern
LA convection and the associated severe risk to slowly develop
northeastward with time. The VAD wind profile at Jackson MS suggests
a veer-back structure with moderate deep and low-level shear, which
will continue to favor semi-organized cluster-type convective modes.
Damaging wind gusts and perhaps a couple of tornadoes may occur with
this activity, and eastward extensions of the watch may become
necessary later this evening. Otherwise, a separate cluster of
storms between Greenville and Vicksburg is advancing into lower
theta-e air in north-central MS and may subsequently weaken through
the evening. The severe risk is greatly lessening to the west of the
ongoing convection.

..Cohen.. 03/30/2017

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...MEG...JAN...LIX...LZK...LCH...SHV...

LAT...LON 29549175 29559374 33719171 33728962 29549175


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[Bama Ravens]

And then the 00z 3km NAM throws this out there:

 

[Bama Ravens]

But, the 3km NAM still brings a band in, that seems to weaken some as it progresses east towards Bham and then east AL.

 

[Richardjacks]

After looking at radar tonight and new models, I am beginning to believe there isn't going to be much in Alabama. Could be wrong, but looking at radar right now, I could see how the line could disrupt the flow and/or reduce CAPE across the state.

 

[Matt Grantham]

I agree this event didn't produce. My wording wasn't overly strong there. You even quoted me as saying "bad outbreak no". I was expecting a couple more tornadoes then what we got. Down in central AL where your located doesn't seem as big a threat. I think we will have a good idea of the severity by morning. I respect your insight since you do this for a living!

You did however say significant tornadoes which to much of the weather community implies EF2+. So just be careful with the wording.

 

[Xenesthis]

After looking at radar tonight and new models, I am beginning to believe there isn't going to be much in Alabama. Could be wrong, but looking at radar right now, I could see how the line could disrupt the flow and/or reduce CAPE across the state.

I agree with you totally. I still think Tennessee has something to worry about though. I will be curious to see the morning conditions

 

[Bama Ravens]

After looking at radar tonight and new models, I am beginning to believe there isn't going to be much in Alabama. Could be wrong, but looking at radar right now, I could see how the line could disrupt the flow and/or reduce CAPE across the state.

Yeah, the line still looks impressive. Could easily see it holding on and making it here, and being disruptive to CAPE values.

 

[Matt Grantham]

After looking at radar tonight and new models, I am beginning to believe there isn't going to be much in Alabama. Could be wrong, but looking at radar right now, I could see how the line could disrupt the flow and/or reduce CAPE across the state.

The upper-level trough never really had that good organized look. A bit too fractured. Also, I'd rather see a faster moving trough to prevent storms from getting too far ahead of the best dynamics.

 

[Richardjacks]

The upper-level trough never really had that good organized look. A bit too fractured. Also, I'd rather see a faster moving trough to prevent storms from getting too far ahead of the best dynamics.

yep, the storms are likely to hold together and move east away from the best dynamics and limit the destabilization when the best dynamics do arrive later. The line will have to start falling apart fairly quickly tonight if this is going to change.

 

[TWBot]

MD 0376 CONCERNING TORNADO WATCH 101... FOR SOUTH CENTRAL MS THROUGH SOUTHEAST LA

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Mesoscale Discussion 0376
NWS Storm Prediction Center Norman OK
0134 AM CDT Thu Mar 30 2017

Areas affected...south central MS through southeast LA

Concerning...Tornado Watch 101...

Valid 300634Z - 300800Z

The severe weather threat for Tornado Watch 101 continues.

SUMMARY...Tornado risk continues to trend downward as primary threat
has transitioned to isolated damaging wind across remaining portion
of tornado watch 101. This watch will be allowed to expire at 08Z.
While some risk for mainly a few strong wind gusts may persist from
southeast LA into southern MS for an hour or two beyond 08Z, the
overall threat is expected to remain too marginal for another WW
issuance.

DISCUSSION...Broken squall line from southern MS into central
portions of coastal LA is moving east at 25-30 kt, while individual
storms embedded within the line move more rapidly northeast. A few
loosely organized storms persist within a portion of the line
including bowing segments across southern and south central MS. VWP
data show largely unidirectional wind profiles with modest size
low-level hodographs. Tendency will be for the low-level jet to
gradually shift north toward the TN Valley and away from the more
unstable portion of the warm sector into the early morning. While
threat for mostly a few strong to damaging wind gusts may persist
next 2-3 hours as storms continue through the marginally unstable
environment, overall threat appears too marginal for an additional
ww issuance.

..Dial.. 03/30/2017

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...JAN...LIX...LCH...

LAT...LON 29769292 30149184 31209075 32369019 32728985 32368949
30888991 29769050 29379186 29769292


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[Bama Ravens]

This line still looks pretty good back over MS. I guess we will be of it holds together and impacts our threat.

 

[Kory]

HRRR showing a very lousy environment for anything major. MCS scouring higher moisture quality from the warm sector, VBV, and then veered surface winds. Somebody get the fork....

 

[Mike S]

I'm hesitant to start a "closing" thread at this moment but Lawrence County, Tn schools are closing today due to the weather threat.

 

[Chris3024]

Looks like the area of rain and storms is fading in southeast Mississippi

 

[Hailey]

. New day one


Sent from my iPhone using TalkWeather mobile app

 

[South AL Wx]

Looks like the Enhanced Risk has been trimmed back quite significantly.

 

[Chris3024]

Gulf coast MCS...FTW

 

[Bama Ravens]

HRRR tries build a band in eastern MS, but it dies out as it crosses Alabama and gets toward Birmingham.