The Annual Countdown to May 1st Thread ©

[Torch Tiger]

Cravings

 

[weatherwiz]

Several days away from the GFS getting into May!!!

[OceanStWx]

On 4/10/2019 at 2:21 PM, weatherwiz said:

Several days away from the GFS getting into May!!!

The folks I know that do this stuff are starting to get a little excited about the end of April and early May...

 

 

...in the Plains.

[weatherwiz]

7 hours ago, OceanStWx said:

The folks I know that do this stuff are starting to get a little excited about the end of April and early May...

 

 

...in the Plains.

Beginning with tomorrow the next 10-days has potential to be quite active overall. Some of the soundings across LA/AR tomorrow are pretty wild. 

Depending on the timing of the front Monday maybe we can even sneak a gusty line or small hail

[Hailstoned]

Gusty line just gone through, Monson, MA-- heavy rain, occasional lightning including one earth thumping cloud to grounder.

[OceanStWx]

Nice plot added to Iowa Environmental Mesonet of categorical risk by calendar day (for WFO or state).

Here's my first year at GYX compared to my last year at DVN...

June 2010 was definitely wild out there. Moderate risk 6 of 9 days there late in the month, and 6/5 and 6/17 were large tornado outbreaks.

[weatherwiz]

3 hours ago, OceanStWx said:

Nice plot added to Iowa Environmental Mesonet of categorical risk by calendar day (for WFO or state).

Here's my first year at GYX compared to my last year at DVN...

June 2010 was definitely wild out there. Moderate risk 6 of 9 days there late in the month, and 6/5 and 6/17 were large tornado outbreaks.

That's sick!!!

[weatherwiz]

Forgot to do the countdown yesterday, but were down to 15 days!!!

[weatherwiz]

Forgot to add...the GFS goes into May now!!!!

[weatherwiz]

11 hours ago, OceanStWx said:

Nice plot added to Iowa Environmental Mesonet of categorical risk by calendar day (for WFO or state).

Here's my first year at GYX compared to my last year at DVN...

June 2010 was definitely wild out there. Moderate risk 6 of 9 days there late in the month, and 6/5 and 6/17 were large tornado outbreaks.

Where on the site is that?

Looked here 

 

https://mesonet.agron.iastate.edu/current/severe.phtml

[OceanStWx]

8 hours ago, weatherwiz said:

Where on the site is that?

Looked here 

 

https://mesonet.agron.iastate.edu/current/severe.phtml

https://t.co/zyLYOKQrhk

[OceanStWx]

Man they added heat maps by hazard type too, and in the significant tornado plot there was one event outlined over parts of New England.

Tried to think off the top of my head what date it could be and failed. Searched IEM and found it within seconds though. 6/6/10 had a 10% hatched tornado. The point I selected in western MA to search for that only had 4 other dates (going back to 2002) that had 10% risk of tornadoes too. And none of those were 6/1/11. 

[weatherwiz]

6 hours ago, OceanStWx said:

Man they added heat maps by hazard type too, and in the significant tornado plot there was one event outlined over parts of New England.

Tried to think off the top of my head what date it could be and failed. Searched IEM and found it within seconds though. 6/6/10 had a 10% hatched tornado. The point I selected in western MA to search for that only had 4 other dates (going back to 2002) that had 10% risk of tornadoes too. And none of those were 6/1/11. 

I remember the 6/6/10 event  

In retrospect I wonder if tornado probs should have ever been that high...there were numerous red flags for that set-up (especially as the day was progressing). The warm sector was full of junk and the lapse rates went to hell. llvl shear was exceptionally strong and we never generated enough instability to yield strong enough updrafts (updrafts were toppled over), and storms quickly oriented into a squall line given the flow and orientation to the front. There did end up being significant microbust wind damage both days though.

 

That was also the weekend with back-to-back tornado watches 

[Hoth]

6 hours ago, OceanStWx said:

Man they added heat maps by hazard type too, and in the significant tornado plot there was one event outlined over parts of New England.

Tried to think off the top of my head what date it could be and failed. Searched IEM and found it within seconds though. 6/6/10 had a 10% hatched tornado. The point I selected in western MA to search for that only had 4 other dates (going back to 2002) that had 10% risk of tornadoes too. And none of those were 6/1/11. 

6/6/10 was one of the more painful severe busts I can remember. I suppose one is always wise to a be a bit skeptical when it comes to NE severe, but that particular day I was so enraptured by the shear and the SPC's bullish maps that I neglected the pitiful lapse rates. A learning experience for sure.

[OceanStWx]

15 minutes ago, Hoth said:

6/6/10 was one of the more painful severe busts I can remember. I suppose one is always wise to a be a bit skeptical when it comes to NE severe, but that particular day I was so enraptured by the shear and the SPC's bullish maps that I neglected the pitiful lapse rates. A learning experience for sure.

[weatherwiz]

9 minutes ago, Hoth said:

6/6/10 was one of the more painful severe busts I can remember. I suppose one is always wise to a be a bit skeptical when it comes to NE severe, but that particular day I was so enraptured by the shear and the SPC's bullish maps that I neglected the pitiful lapse rates. A learning experience for sure.

I'm not really sure you can call it a bust...it was still a pretty solid event (golf ball sized hail in CT and two swaths of impressive wind damage). The tornado aspect of it "failed" but numerous storms exhibited strong rotation and several TOR's had been issued. 

 

The lapse rates I think were supposed to be so much better than what ended up happening but the warm sector was just full of clouds and crap. Another issue too was really high LCL's...which likely prohibited any TOR's. 

 

[Hoth]

1 hour ago, weatherwiz said:

I'm not really sure you can call it a bust...it was still a pretty solid event (golf ball sized hail in CT and two swaths of impressive wind damage). The tornado aspect of it "failed" but numerous storms exhibited strong rotation and several TOR's had been issued. 

 

The lapse rates I think were supposed to be so much better than what ended up happening but the warm sector was just full of clouds and crap. Another issue too was really high LCL's...which likely prohibited any TOR's. 

 

The bust may be more that there wasn't a single tornado reported when people were weenieing out and proclaiming the second coming of the Worcester tornado in the morning. There were certainly some solid storms. Wasn't there a macroburst in the Boston burbs? Anyway, in my hood it was just a bunch of milky clouds and filtered sun and that was about it. I also forgot about the LCL being high. I may not have been aware of that parameter back then, but it's certainly on my radar now. This board has been a great education for this weenie. 

[weatherwiz]

2 minutes ago, Hoth said:

The bust may be more that there wasn't a single tornado reported when people were weenieing out and proclaiming the second coming of the Worcester tornado in the morning. There were certainly some solid storms. Wasn't there a macroburst in the Boston burbs? Anyway, in my hood it was just a bunch of milky clouds and filtered sun and that was about it. I also forgot about the LCL being high. I may not have been aware of that parameter back then, but it's certainly on my radar now. This board has been a great education for this weenie. 

This is where the problem lies. You would think those who have a background in weather and at least a basic understanding of weather could understand it's all probability, but people just "assume". A 10% hatched area doesn't necessarily mean there will be tornadoes (I mean as a forecaster you're likely expecting there will be some). A 10% chance of a tornado with 25-miles of a point is pretty dang high but still doesn't mean it will happen. 

There will also several tornado warnings that day...so the atmosphere was conducive for mesocyclones and strong rotation which was highlighted within forecasts (hence the elevated tornado probabilities) and that did happen, but there were other factors which prohibited tornadoes. 

Yes there was outside one outside of Boston and the following day one in/around BDL.

[Hoth]

9 minutes ago, weatherwiz said:

This is where the problem lies. You would think those who have a background in weather and at least a basic understanding of weather could understand it's all probability, but people just "assume". A 10% hatched area doesn't necessarily mean there will be tornadoes (I mean as a forecaster you're likely expecting there will be some). A 10% chance of a tornado with 25-miles of a point is pretty dang high but still doesn't mean it will happen. 

There will also several tornado warnings that day...so the atmosphere was conducive for mesocyclones and strong rotation which was highlighted within forecasts (hence the elevated tornado probabilities) and that did happen, but there were other factors which prohibited tornadoes. 

Yes there was outside one outside of Boston and the following day one in/around BDL.

Yeah I think the rarity of seeing a 10% hatched tornado probability went to a lot of our heads and many threw caution to the wind. I certainly can't remember another comparable SPC forecast except maybe May '98. Excitement often overrides sober judgment. 

[weatherwiz]

8 minutes ago, Hoth said:

Yeah I think the rarity of seeing a 10% hatched tornado probability went to a lot of our heads and many threw caution to the wind. I certainly can't remember another comparable SPC forecast except maybe May '98. Excitement often overrides sober judgment. 

There are times where some of the convective outlooks are a little scratching here where some events that shouldn't be overplayed are and ones that should be played up aren't. Heck...even 6/1/11 only had 5% TOR probs...so if you compare 6/1/11 and 6/6/2010 you would probably think you would see the 10% probs on 6/1 and 5% on the other. 

Anyways...if I remember correctly things looked quite impressive leading up to 6/6/2010 and things went to crap in the AM. I'm trying to remember what the models were showing for lapse rates leading up to 6/6. I think there were some hints at a pseudo EML 

[Cyclone-68]

Any potential EML intrusions foreseen the next 10 days?

[OceanStWx]

On 4/17/2019 at 9:04 AM, weatherwiz said:

This is where the problem lies. You would think those who have a background in weather and at least a basic understanding of weather could understand it's all probability, but people just "assume". A 10% hatched area doesn't necessarily mean there will be tornadoes (I mean as a forecaster you're likely expecting there will be some). A 10% chance of a tornado with 25-miles of a point is pretty dang high but still doesn't mean it will happen. 

There will also several tornado warnings that day...so the atmosphere was conducive for mesocyclones and strong rotation which was highlighted within forecasts (hence the elevated tornado probabilities) and that did happen, but there were other factors which prohibited tornadoes. 

Yes there was outside one outside of Boston and the following day one in/around BDL.

Really the correct way to look at the probs is with respect to climo. So actually a 10% means much more in New England than it does in say OK.

That week in June, any given day is roughly a 0.1% (not 1%) chance of a tornado within 25 miles of a point. So a 10% risk is 100 times more likely to occur on that day. So a 5% risk on 6/1 is actually still 50 more likely than any given day. Both are really large departures from a typical day.

For western OK on the same days a 10% tornado risk is only about 8 times more likely.

[weatherwiz]

On 4/20/2019 at 12:54 PM, OceanStWx said:

Really the correct way to look at the probs is with respect to climo. So actually a 10% means much more in New England than it does in say OK.

That week in June, any given day is roughly a 0.1% (not 1%) chance of a tornado within 25 miles of a point. So a 10% risk is 100 times more likely to occur on that day. So a 5% risk on 6/1 is actually still 50 more likely than any given day. Both are really large departures from a typical day.

For western OK on the same days a 10% tornado risk is only about 8 times more likely.

That's funny you mention this b/c I was just reading some literature on the SPC site on Friday which discussed this. I knew climo was a bit of a factor, but never really fully understood to what degree. I was trying to find some info too as to where the percentages are derived...like what influences a 2% risk or 5%...and so forth. For example...it seems like the risk categories are influenced by the SPC SREF severe wx probs. 

[OceanStWx]

1 hour ago, weatherwiz said:

That's funny you mention this b/c I was just reading some literature on the SPC site on Friday which discussed this. I knew climo was a bit of a factor, but never really fully understood to what degree. I was trying to find some info too as to where the percentages are derived...like what influences a 2% risk or 5%...and so forth. For example...it seems like the risk categories are influenced by the SPC SREF severe wx probs. 

I've never actually seen how they determine the daily percentages, I just know that they are related to climo in that way.

But daily risks are still a measure of your relative risk on that day. If you see a 45% wind, it is still saying there is a 45% (or basically a coin flip) chance that someone within 25 miles of you loses a tree or two. But depending on the time of year that may also represent a huge increase in threat from climo.

[weatherwiz]

14 hours ago, OceanStWx said:

I've never actually seen how they determine the daily percentages, I just know that they are related to climo in that way.

But daily risks are still a measure of your relative risk on that day. If you see a 45% wind, it is still saying there is a 45% (or basically a coin flip) chance that someone within 25 miles of you loses a tree or two. But depending on the time of year that may also represent a huge increase in threat from climo.

Perhaps they're heavily tied into climo and then the forecaster just uses knowledge of the setup and past events to ultimately determine the percentages? 

[weatherwiz]

9 days away!!!!

Now that we're within 10 days we can do a daily countdown...it's like a slow motion New Year's Eve ball drop 

[OceanStWx]

9 hours ago, weatherwiz said:

Perhaps they're heavily tied into climo and then the forecaster just uses knowledge of the setup and past events to ultimately determine the percentages? 

Knowing SPC and how they operate I would be surprised if there is too much subjectivity built into it. MCDs, sure, but not the outlooks.

[weatherwiz]

14 hours ago, OceanStWx said:

Knowing SPC and how they operate I would be surprised if there is too much subjectivity built into it. MCDs, sure, but not the outlooks.

It probably is actually better that way actually...otherwise there would really be no baseline for determining risk categories and categorical percentages. I can't believe after all these years I never fully understood/grasp the whole background behind them. This has been very inspiring...I may throw together a blog post b/c it pisses me off when people on Twitter say "I think the SPC should do 10% TOR or 5%" or whatever

[weatherwiz]

8 days!!!

[weatherwiz]

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