Severe WX April 12-15th, 2018 Severe Potential

[jmills]

I know I'm a little late, but COD is almost always going to be faster than SPC.

 

[HazardousWx]

The bmx office said their forecasts were suffering by aligning with the SPC. They told media partners to expect these differences to continue.

Wow....thats pretty bold to say for the NWS. They usually don't say stuff like that publicly.

 

[SilentShadow87]

Wow....thats pretty bold to say for the NWS. They usually don't say stuff like that publicly.

To be completely fair the SPC dropped the ball quite a few times in the last year, and whenever they do they and the NWS seem to get slammed by the public. Most people don't understand that these sorts of forecasts are incredibly tricky. Even when the storms are hours away there can be last-minute variables that completely change the stage for events later in the day. Sometimes that means a bust, sometimes an over-performer. But for some reason people generally don't seem to get that.

 

[Fred Gossage]

Wow....thats pretty bold to say for the NWS. They usually don't say stuff like that publicly.

From what I have understood via inner rumblings within the Alabama professional weather community, BMX made a significant effort to coordinate with SPC ahead of outlooks, so that there would not be any disagreement between the SPC and local maps, but BMX would still have some input on things if they had ideas on the local scale that differed than the SPC thought process. From what I understand, the not-BMX side had zero interest in any coordination. BMX has done their part...

 

[Xtreme Weather]

The bmx office said their forecasts were suffering by aligning with the SPC. They told media partners to expect these differences to continue.

Geez would be interesting to see the data, research and events that are driving this from NWS offices. Or is this specific to the BMX office? I know they can add or take away counties when a watch is issued by the SPC and I get that but to basically call out the SPC is notable to say the least.

Edit this may need its own thread I dunno just a thought to keep from taking away from the threads original purpose

 

[KoD]

It's setups like this one, with much uncertainty and model disagreement, that I don't envy being a degreed meteorologist whose task is to warn tons of thousands of people about severe weather.
Armchair forecasting is much less stressful :]

 

[Fred Gossage]

It looks like all of the CAMs this morning, even the GFS-based WRF runs, are trending slower. Even the Baron BAMS is trending slower, with 1000 CAPE as far northwest as Florence as late as 11am tomorrow.

 

[rolltide_130]

It's setups like this one, with much uncertainty and model disagreement, that I don't envy being a degreed meteorologist whose task is to warn tons of thousands of people about severe weather.
Armchair forecasting is much less stressful :]

The line between a potentially significant outbreak and a total dud is about as thin as I've ever seen it with this system. This is one of the more difficult forecasts I've seen.

 

[tennessee storm chaser]

if i were chasing today... i would setup just west of little rock ark... out head of the approaching dry line... winds look directional also...

 

[SilentShadow87]

Wow....thats pretty bold to say for the NWS. They usually don't say stuff like that publicly.

To be completely fair the SPC dropped the ball quite a few times in the last year, and whenever they do they and the NWS seem to get slammed by the public. Most people don't understand that these sorts of forecasts are incredibly tricky. Even when the storms are hours away there can be last-minute variables that completely change the stage for events later in the day. Sometimes that means a bust, sometimes an over-performer. The problem is that generally people have a hard time understanding that.

 

[buckeye05]

While we’re on the topic, lots of questions being raised about the 15% moderate today. Pretty bold call with all the remaining uncertainty regarding the directional shear, VBV, and storm mode.
We’ll see at least a few tornadoes this evening, but I think it will messy.

 

[Xtreme Weather]

Started thread for the NWS and SPC discussions

https://talkweather.com/index.php?threads/nws-vs-spc-convective-outlook-discussion.1014/

 

[Weatherphreak]

Waff and Brad Travis have really built this up all week. I don’t think there was this many Facebook lives and what not for the March storm. I was worried this may be a dud for North Alabama with the morning line but with it slowing down we may get those discrete cells popping out in front of the line. I may be wrong but I recall people saying the 89 Tornado in Huntsville was a result of the supercell merging with the squall line as it came through. I feel like usually the opposite is true and this lowers the tornado threat. Anyone know more about this?

 

[HazardousWx]

Waff and Brad Travis have really built this up all week. I don’t think there was this many Facebook lives and what not for the March storm. I was worried this may be a dud for North Alabama with the morning line but with it slowing down we may get those discrete cells popping out in front of the line. I may be wrong but I recall people saying the 89 Tornado in Huntsville was a result of the supercell merging with the squall line as it came through. I feel like usually the opposite is true and this lowers the tornado threat. Anyone know more about this?

I remember that day. I was in the 11th grade back then. Did you see the writeup from NWS on it? https://www.weather.gov/hun/hunsur_1989-11-15_tornadodetails

 

[South AL Wx]

The new SPC Day 2 Outlook added a hatched area across portions of southeast LA, east MS, and west AL:

A couple of snippets from the discussion:

...SUMMARY...
Strong to severe storms are expected across the lower Mississippi
Valley and central Gulf Coast States with a threat for damaging
winds and a few tornadoes, some possibly strong. Isolated severe
storms will be possible in the Midwest Saturday afternoon to early
evening.

Given the strength of the
southerly low-level jet (50-60 kt) and low-level shear, strong/
damaging winds (some significant) and a strong tornado or two will
be possible from southeast LA through eastern MS and western AL
Saturday afternoon into the evening.

http://www.spc.noaa.gov/products/outlook/day2otlk.html

 

[warneagle]

MD is up for the eventual tornado watch over the moderate risk area, mentions potential PDS.

 

[Richardjacks]

The new SPC Day 2 Outlook added a hatched area across portions of southeast LA, east MS, and west AL:

A couple of snippets from the discussion:



http://www.spc.noaa.gov/products/outlook/day2otlk.html

I am trying to understand the placement of the hatched area...seems a little too far west to me...I would think the outflow boundary would be well into the western part of that area...at least in northern sections

 

[warneagle]

Tornado watch is up in OK/KS/TX/AR, not the one over the moderate risk area yet.

 

[South AL Wx]

PDS Tornado Watch has been issued:

>95/80 probs for tornadoes.

http://www.spc.noaa.gov/products/watch/ww0040.html

 

[Fred Gossage]

I am trying to understand the placement of the hatched area...seems a little too far west to me...I would think the outflow boundary would be well into the western part of that area...at least in northern sections

I'm not so sure anymore. CAMs are trending slower, even the GFS-based ones. Even the Baron BAMS that had been the fastest all along has 1000+ CAPE and discrete cellular storms as far north/west as Florence AL, Iuka MS, Booneville MS, late tomorrow morning and beyond. I do think the hatched area would need to extend eastward, though. I probably would've just hatched the entire 30% area if I was doing the outlook.