Severe WX Severe Weather Threat 4/2/17-4/3/17

[KoD]

WOW I would never call any model ".most reliable model ever," never ever

Especially teh most reliable model ever, GFS!!! Here is my site-I obviously like teh Euro!

http://wiregrasswxdawg.com/

Hah. Modified word censor, I used to apply one for international pirate day to make everyone say AAAaaarrgg! And speak like pirates! Very fun. Used well I think. I wonder how many are new today, two are obvious.

Anyway, as said above there's a few little things that can go wrong with this event if you're looking for tornadoes.. but there's been good model consistency, better than last event at least. I think we'll definitely see some powerful wind gusts with this one.

 

[stormcentral]

Sent from my LGLS775 using TalkWeather mobile app

 

[stormcentral]

Day 2 moderate. Day 3 slight.

Sent from my LGLS775 using TalkWeather mobile app

 

[Kory]

Don't sleep on Wednesday for places in MS/AL/FL Panhandle. If we can get the loaded air mass over the Gulf to move north, we're talking some serious thermos. Right now, question is gping to be how far can that make it north....

Euro was bullish from overnight.

 

[MattW]

12z NAM is showing a SigTor up to about 3 south of Atlanta right around Monday afternoon rush hour.

 

[CheeselandSkies]

N.A.M. soundings for Sunday evening show pretty bad veer-back over TX where CAPE values are progged to be highest. Instability drops off with eastward extent into LA, but it is still strong (especially by early April standards) and hodographs are much more impressive.

This setup has its potential flies in the ointment but overall soundings and forecast parameter spaces look more ominous than the previous Day 2 MDT.

 

[Equus]

MOB states on its graphics that they are also pretty much expecting an upgrade from Slight. Going to be a very interesting upcoming week.

 

[Bama Ravens]

Wow, wow, wow. Could be a legit shot at having a high risk and PDS tornado watch in SE Texas and western LA tomorrow.

 

[Kory]

One potential problem tomorrow could be a convective bomb that goes off. With those types of CAPE values and excessive forcing expected, I'd weary of an explosion in coverage which COULD limit the threat.

Wednesday continues too look very interesting for MS/AL. Large positively tilted trough with a great warm sector....

 

[Bama Ravens]

One potential problem tomorrow could be a convective bomb that goes off. With those types of CAPE values and excessive forcing expected, I'd weary of an explosion in coverage which COULD limit the threat.

Wednesday continues too look very interesting for MS/AL. Large positively tilted trough with a great warm sector....

True, some models have large areas of convection ahead of the more discrete cells.

 

[PerryW]

This synoptic pattern reminds me a great deal of November 21-23, 1992. I remember a good meteorologist friend who told me if that had happened in April, would have been catastrophic for Georgia (it was bad enough as it was; 2 F4 and 3 F3's in GA/ 6 dead); wonder if we;re about to find out.

 

[Equus]

The AFD from BMX this morning is interesting. They really seem to be concerned about Wednesday. Rather potent instability with trends toward more volatile low level wind parameters. The term 'serious severe weather event', even when modified by 'potential' and 'if trends continue', jumps out at the reader.

Not that wiki is a reliable source, but I'm guessing that they're backed up by SPC data to suggest this is the most active pre-April tornado period since 2008 and one of the most active on record. Not that we will be close to 2011's April numbers, but we could beat it for a couple of weeks early into the month... doubt it though.

 

[Kory]

The AFD from BMX this morning is interesting. They really seem to be concerned about Wednesday. Rather potent instability with trends toward more volatile low level wind parameters. The term 'serious severe weather event', even when modified by 'potential' and 'if trends continue', jumps out at the reader.

Not that wiki is a reliable source, but I'm guessing that they're backed up by SPC data to suggest this is the most active pre-April tornado period since 2008 and one of the most active on record. Not that we will be close to 2011's April numbers, but we could beat it for a couple of weeks early into the month... doubt it though.

12z Euro argues a higher end threat Wednesday....

 

[TWBot]

MD 0392 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF THE TX BIG COUNTRY AND VICINITY

​

Mesoscale Discussion 0392
NWS Storm Prediction Center Norman OK
0231 PM CDT Sat Apr 01 2017

Areas affected...Portions of the TX Big Country and vicinity

Concerning...Severe potential...Watch possible

Valid 011931Z - 012200Z

Probability of Watch Issuance...60 percent

SUMMARY...Portions of the Big Country of TX and vicinity are being
monitored for increasing severe-thunderstorm potential this
afternoon, and a watch may become necessary for parts of the area.

DISCUSSION...Surface observations and recent visible satellite
imagery indicate a quasi-stationary boundary extending from west of
Wichita Falls to a triple-point low near Howard County to the TX
Trans-Pecos region. A dryline arches from the low to the Stockton
Plateau, with a plume of 8-9-C/km lapse rates in the lowest 3 km AGL
extending from the TX Trans-Pecos region to the proximity of the
dryline circulation. Meanwhile, within the warm/moist sector,
poleward moisture transport continues, with dewpoints in the
lower/middle 60s as far north as a wavy, diffuse warm front / marine
boundary analyzed from southern parts of the Low Rolling Plains to
northern parts of central TX. Steep midlevel lapse rates surmounting
the warm/moist boundary layer are supporting MLCAPE around
1000-2500 J/kg near and south of the warm front, which should slowly
build northward during the next several hours.

Relatively more widespread insolation across the western fringes of
the warm/moist sector has given way to increasingly agitated
boundary-layer cumulus fields within about 60-90 miles east of the
dryline. Related erosion of capping, further bolstered by modest
midlevel ascent accompanying a meridionally oriented midlevel speed
maximum glancing the area, should contribute to surface-based
convective development over western sections of the MCD area in the
20-21Z time frame. Thunderstorms will spread generally eastward and
northeastward into the evening hours.

The presence of 35-50 kt of effective shear will support organized
convective structures, including initial supercells/supercell
clusters, capable of large hail and damaging winds. Except for a
small area just south-southeast of the triple point, shear vectors
are oriented generally parallel to initiating boundaries. As a
result, there should be a tendency for convection to locally grow
upscale, mitigating the tornado risk. Nevertheless, pre-existing
vertical vorticity overlapping more robust low-level CAPE near the
triple point could support a tornado or two with the more robust
discrete cells, initially. However, the tornado risk should be
limited by the eventual transition to more linear modes, along with
weak low-level shear.

Farther to the east across north TX, the development of sustained,
surface-based convection is uncertain owing to the lack of stronger
deep ascent. The peripheral influence of the midlevel speed maximum
could offer some potential for thunderstorm development, though this
activity may remain rooted above a stable layer to the north of the
warm front. However, relatively longer/more curved low-level
hodographs with eastward extent across the region, and similarly
favorable deep shear, will offer conditional potential for supercell
storms/clusters to develop. Large hail and damaging winds could
accompany this activity, along with some tornado potential,
especially later in the afternoon and into the evening. This
potential will largely depend upon whether storms form in the more
modest warm-advection plume to the east, and whether storms ingest
surface-based effective inflow -- both factors are presently
associated with marked uncertainty.

..Cohen/Hart.. 04/01/2017

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

ATTN...WFO...FWD...OUN...SJT...LUB...MAF...

LAT...LON 31320006 31380070 31680103 31990126 32430124 32880057
33320003 33669945 33909871 33819806 33419761 32679764
31999822 31579908 31320006


Read more

For additional SPC information click here

 

[Kory]

NAM is being quite bullish with convection behind the Monday morning MCS that comes roaring across MS/AL. One would think subsidence would kill any of that, but will have to keep an eye on that. That environment holds potential for severe.

 

[PerryW]

NAM is being quite bullish with convection behind the Monday morning MCS that comes roaring across MS/AL. One would think subsidence would kill any of that, but will have to keep an eye on that. That environment holds potential for severe.

It's early April when crazy things can and have happened over the years. In 1936, Georgia was struck by violent tornadoes on the evening of April 1st, morning of April 2nd,...........Mississippi struck by a F5 late on April 5th.......and Georgia by another F4 again on the morning of April 6th. Between the April 1-2 and April 5-6 tornado outbreaks, a late season freeze occurred in Atlanta, GA with 31 on the 3rd and 30 on the 4th. It then became so warm and unstable so quickly a F5 tornado obliterated Tupelo, MS less than 38 hours later. Atlanta also recieved nearly 8" inches of rain that week.


I also remember THREE killer tornadoes to strike north Alabama and north/middle Georgia in a week.........April 1st, 3rd-4th, and 7-8th, 1974. It can get crazy this time of year sometimes, and am afraid it's about to happen again

 

[TWBot]

MD 0393 CONCERNING SEVERE THUNDERSTORM WATCH 106... FOR PORTIONS OF THE TEXAS BIG COUNTRY AND EDWARDS PLATEAU

​

Mesoscale Discussion 0393
NWS Storm Prediction Center Norman OK
0554 PM CDT Sat Apr 01 2017

Areas affected...Portions of the Texas Big Country and Edwards
Plateau

Concerning...Severe Thunderstorm Watch 106...

Valid 012254Z - 020030Z

The severe weather threat for Severe Thunderstorm Watch 106
continues.

SUMMARY...Strong/severe thunderstorms will persist across primarily
central and southern portions of Watch 106 this evening.
Additionally, a southward expansion may be necessary if convective
trends warrant.

DISCUSSION...Through 22Z, the severe threat in Watch 106 has been
confined to a supercell that formed near a triple point near the
I-20 corridor this afternoon. However, this storm has become rooted
above a shallow surface stable layer, as a cold front steadily
pushes southeast across the Big Country. With this cell becoming
progressively displaced from warm/moist surface air, continued
weakening is probable. However, persistent large-scale ascent and
considerable effective shear may maintain some threat for large hail
with any cell that develops across northern portions of the watch.

Farther south, convection has attempted to organize from the
dryline/cold front intersection to points southeastward along a
remnant boundary extending towards Llano, TX. Overall, weak surface
convergence and mid-level flow perpendicular to this initiating
boundary have given cells a rather elongated, marginal structure.
While the cold front will gradually undercut the northwestern extent
of these cells, a band of ascent aloft (noted in water vapor
imagery) may yield a few stronger cells near/south of the ongoing
watch (either along the dryline/cold front or the remnant boundary).
Here, steep mid-level lapse rates and ample effective shear would
yield a threat for both large hail and damaging winds with more
robust cells. As such, southward expansion of the ongoing watch may
be needed if convective trends warrant.

..Picca.. 04/01/2017

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

ATTN...WFO...FWD...SJT...LUB...MAF...

LAT...LON 31550119 32830030 33369928 33289862 31709871 30559922
30389959 30370112 30660143 31550119


Read more

For additional SPC information click here

 

[TWBot]

MD 0394 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF THE EDWARDS PLATEAU

​

Mesoscale Discussion 0394
NWS Storm Prediction Center Norman OK
0720 PM CDT Sat Apr 01 2017

Areas affected...Portions of the Edwards Plateau

Concerning...Severe potential...Watch unlikely

Valid 020020Z - 020145Z

Probability of Watch Issuance...20 percent

SUMMARY...A localized threat for strong wind gusts and large hail
may exist with cells crossing the Rio Grande River over the next
hour. However, the threat should remain too small in spatial extent
for watch issuance within the next 2-3 hours.

DISCUSSION...Left and right splits of a cell that organized over the
Serranias del Burro are approaching the Rio Grande this evening,
aided by a band of ascent associated with an upper-level southerly
jet. While deeper moisture remains displaced to the east (evident in
the 00Z DRT sounding), steep low/mid-level lapse rates and
relatively straight, elongated hodographs (representing around 50-55
kt of effective shear) may maintain one or both of these cell splits
as they enter Texas. Moreover, occasional updraft organization from
strong southwesterly mid-level flow may yield isolated large hail.
Strong, gusty winds also remain a possibility considering the deeply
mixed boundary layer. Nonetheless, a lack of more substantial
moisture and forcing for ascent should keep this severe threat
brief/localized, precluding watch issuance.

By late evening into early tonight, a more substantial threat should
materialize, as low-level moisture surges west and convection
re-develops along higher terrain. However, this scenario will be
addressed in a later mesoscale discussion.

..Picca/Edwards.. 04/02/2017

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

ATTN...WFO...EWX...MAF...

LAT...LON 29810188 30050189 30270158 30220103 29810049 29510033
29220049 29170073 29560121 29730143 29810188


Read more

For additional SPC information click here

 

[apocalyptic_pleasures]

First tornado OTG in TX

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 845 PM CDT FOR
SOUTHEASTERN COLEMAN COUNTY...

At 825 PM CDT, a confirmed large and extremely dangerous tornado was
located 7 miles southwest of Santa Anna, moving east at 20 mph.

This is a PARTICULARLY DANGEROUS SITUATION. TAKE COVER NOW!

HAZARD...Damaging tornado.

SOURCE...Spotter confirmed tornado.

IMPACT...You are in a life-threatening situation. Flying debris may
be deadly to those caught without shelter. Mobile homes
will be destroyed. Considerable damage to homes,
businesses, and vehicles is likely and complete destruction
is possible.

The tornado will be near...
Santa Anna around 845 PM CDT.

Other locations impacted by this tornadic thunderstorm include
Mozelle, Fisk and Shields.

 

[TWBot]

MD 0395 CONCERNING SEVERE THUNDERSTORM WATCH 106... FOR PORTIONS OF CENTRAL TEXAS

​

Mesoscale Discussion 0395
NWS Storm Prediction Center Norman OK
0844 PM CDT Sat Apr 01 2017

Areas affected...Portions of central Texas

Concerning...Severe Thunderstorm Watch 106...

Valid 020144Z - 020245Z

The severe weather threat for Severe Thunderstorm Watch 106
continues.

SUMMARY...The ongoing severe threat associated with Watch 106 will
likely be focused with a supercell thunderstorm over Coleman County
and nearby thunderstorms over the next 1-2 hours.

DISCUSSION...KSJT radar data depict a high-precipitation supercell
over Coleman County as of 0130Z, with the overall storm motion
eastward around 15 kt. This storm has possessed a rather broad, but
persistent low/mid-level mesocyclone, in turn favoring this deviant
motion to the east. Additionally, updraft organization has promoted
considerable large-hail growth, with recent MRMS MESH and dual-pol
data suggesting hail diameters occasionally over 2 inches. Indeed, a
report of giant hail was received in Valera, TX at 0112Z.

As cell propagation takes this storm eastward into a plume of higher
surface dew points, a threat for large hail and damaging winds may
persist. However, a cold front is undercutting this supercell,
resulting in slow weakening with time. Occasional large hail may
remain possible with this cell or others developing over the
post-frontal stable layer this evening. As such, convective trends
could require watch extension in space/time over the next 1-2 hours.

..Picca.. 04/02/2017

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

ATTN...WFO...FWD...SJT...

LAT...LON 31300090 31740012 32659919 32999893 33049850 32459837
31519845 31149926 31070045 31300090


Read more

For additional SPC information click here