weatherwiz

On 10/30/2018 at 9:47 AM, 40/70 Benchmark said:

I encountered the same issue earlier this saeason. I decided to consider the modoki value during the tri monthly peak...aka, if we had a NDJ peak, then I use the modoki value for that particular period.

From what I've gathered through various papers this seems to be a popular method. 

Does anyone remember the date of the (I think it was a PDS) tornado watch in May of 2003 that turned into a bust? 

The way this year has gone I'm expecting 2-3 tornadoes tomorrow lol.

Seriously though...certainly some potential for some strong-to-severe thunderstorms. I would like to see 0-3km CAPE higher but 0-6km CAPE is decent so if we can utilize that there is plenty of wind shear to work with. I think we could see a line of strong-to-severe Saturday AM into PM across the Cape.

Also, that is QUITE the vigorous s/w coming through Saturday. That thing means business. Even looks like a nice tropopause fold upcoming with it.

Wild morning indeed. Thanks for sharing the story, @StormSurge Unlike last week, at least this potential was picked up a bit by some. Again, pretty high 0-3km CAPE with some decent sc vorticity, steep lapse rates, and potent s/w.

The latest confirmed tornado in CT marks 9 on the year for the state which breaks the record of 8 in 1973. I think between CT/MA/RI alone we're at 18 tornadoes. I don't remember off hand how many have occurred in VT/NH/ME. 

4 minutes ago, raindancewx said:

I generally classify ENSO events by DJF anomalies for the entire July-Jun period, so long as the classification lasts for more than six months between July-June since the leading indicators of a winter La Nina or El Nino (SOI, subsurface, pattern changes) will start to show up before the classification begins. In Spring, like Fall, you have less variation in ONI magnitude, there is no -2 or +2 three-month period like you can have in winter. So it becomes less of a big deal that a lot of the weak La Nina or El Nino events in MAM are only +0.2 or -0.3, etc in Spring.

Thanks for the input! This makes a tremendous amount of sense especially considering the ENSO seems to be strongest during the northern hemisphere cool season. So maybe for my purpose I should just focus on like the DJF and JFM periods? 

I think my issue here is I just want to be too perfect and sort of "over-analyze". FWIW, in my conclusion I also plan on explaining the limitations within my research and explaining how these limitations can be explored further 

I am working on my senior research and I am stuck with something and I was hoping to get some guidance/opinions/suggestions from here...and this will be incorporated within my presentation/paper in terms of sourcing. 

Unless anyone is interested I will refrain from explaining the total jest of my research...1) to spare the boredom and 2) it would make this post longer than needed. 

Anyways, to simply I am doing my research involving tornadoes and I am focusing on the spring. Within my research I will be putting a focus onto ENSO and what I would like to do is breakdown ENSO not only into phase but the strength of the phase as well as where the anomaly was centered (so like west-based, east-based, central, etc). 

What I am struggling with is coming up with a threshold for doing these breakdowns and this is due to the atmospheric-oceanic lag that exists. Let's look at 1972-1973, for example. That winter was a strong EL Nino (well super-strong) but by definition, it officially ended in the FMA trimonthly period and by that point it was weak. So keeping in mind my my focus is spring (MAM). So, what would be the best way to classify that spring into? 

Maybe there is just no way to directly quantify an event just b/c of the variability in strength and the unknown with regards to the atmospheric-oceanic lag. 

If needed, I can explain what my vision is further and any input/suggestions will be sourced within my presentation. 

yeah Funky's was awesome and certainly central-based. Only problem is parking kinda sucks. I think we should shoot for a Saturday though...right in the middle of the weekend and it avoids Friday traffic

On the following link you can do composites for only up to 20 different years. Is there any source where you can do more than 20-years?

https://www.esrl.noaa.gov/psd/cgi-bin/data/composites/printpage.pl

4 minutes ago, CoastalWx said:

Look at that pressure fields. You can see some funny looking mesoscale ridges and troughs within the area of low pressure. Just seems bizarre and exaggerated to me. 

Yeah that does seem rather odd...it's striking too how obvious that is. Great catch though picking that out. Very curious now as to the cause of this within the model. Even tracing this back to when it's off the mid-Atlantic coast there are signs of these features developing but they become more exaggerated as the system progresses northward. Is it possible it's some sort of interaction with the high to the north? But it's almost like whatever is used within the algorithm for SLP/QPF didn't like do any smoothing of the data.

I also love how this run pulls the H7 low quite west lol. Lots of funky things this run

5 minutes ago, CoastalWx said:

The structure of it. The winds and QPF distribution on the 3 and 6 hr panels shows several upward/downward vertical motion areas that seem exaggerated. 

Ahhh...I see exactly what you're talking about. 

Could it be tied with the 700mb VV? Looking at 700mb VV you have almost a similar type of configuration. Or would that be tied into what you were saying with gravity wave induced pressure fields?

1 hour ago, CoastalWx said:

WTF is the GFS doing now? Anybody else noticing lately that it is doing these weird almost gravity wave induced pressure fields affecting srfc winds and precip? That looks unrealistic as modeled. Sure they can happen, but look at the winds and QPF on the 6z GFS. 

are you talking about the structure of the QPF or total QPF? 

1 hour ago, weatherwiz said:

ughhh it's not that. I'm using an incorrect equation or method to find e. The book gives e = es - Ap(T-Tw) but I think it's full of poop. 

haha...completed the whole chart!!! only took 2.5 pages of calculations. Hopefully it's all right but numbers make sense  

14 minutes ago, weatherwiz said:

I think I found my issue...converting to K. I don't think you're supposed to convert to K. Just keep the C   

ughhh it's not that. I'm using an incorrect equation or method to find e. The book gives e = es - Ap(T-Tw) but I think it's full of poop. 

I think I found my issue...converting to K. I don't think you're supposed to convert to K. Just keep the C   

1 minute ago, dendrite said:

Are you trying to calculate for e_s here? You plugged Tw in there to find e which I don't think is correct...isn't that supposed to be Td which you don't have? e_s should be 23 something.

yes I did get 23.47 when solving for es. 

When I used the equation

e = es - Ap(T-Tw) A = 0.00062°C-1 p = 800 hPa T = 20C Tw = 18C I obtained 23.47 - .992 = 22.478 for e. 

When I did the 19.7 they show for e divided by 23.47 I get the 84% RH but when I use my e divided by my es I get like 96% RH. 

So I'm doing something wrong with calculating for e I think.

but...this is for the first column where they already have everything filled in...I'm just trying to work the process to see if I get similar numbers so I know I'm doing the rest of the columns correctly. The rest of the columns we're only given P, T, and Tw which makes it more difficult lol

30 minutes ago, weatherwiz said:

I got just over 20. I used the Clausius-Clapeyron for using Td since knowing Td you can directly find e...which is what is needed to find. They got 19.7. I have tried moving onto solving the rest of the columns...figuring if I could at least get the same values they did for column 1 it means I'm using the right equations. I did get the correct mixing ration they got and RH but for some reason my e is off. I have found es and when I divide the e they have by my es I get 84%...but when I divide by my e and es I get much greater than 84%.

 Is it possible to find Td given just temp and Tw?

well I did end up with their value of e (19.70. Used e = wp / 0.622 + w)

But now I'm see where I'm confused...

It's figuring out exactly which of the variables I can solve for first given only P, T, and Tw. But I think I may have it...RH can be calculated this way and it would involve finding es...and if I know es and RH I can find e and w!!!

5 minutes ago, dendrite said:

My bad...was thinking the RH was given. What are you getting for a value for e?

I got just over 20. I used the Clausius-Clapeyron for using Td since knowing Td you can directly find e...which is what is needed to find. They got 19.7. I have tried moving onto solving the rest of the columns...figuring if I could at least get the same values they did for column 1 it means I'm using the right equations. I did get the correct mixing ration they got and RH but for some reason my e is off. I have found es and when I divide the e they have by my es I get 84%...but when I divide by my e and es I get much greater than 84%.

 Is it possible to find Td given just temp and Tw?

20 minutes ago, dendrite said:

RH = (e/es)*100?

I did that and was able to obtain the RH they did. So I was assuming the es value I obtained was correct b/c when I did the 19.7 for e divided by my es I got 84%.

But what stumps me is beginning to fill out the second column given only the temp, dewpoint, and pressure. My newest guess is figuring out dewpoint given the temp, wet-bulb and once I know dewpoint I can find e then w, and everything else falls into place 

18 minutes ago, dendrite said:

idk why but seeing you write the natural log in all caps is really bothering me more than it should. lol

I am quite stuck on something and I can't figure this out. 

I need to fill out this table and the first column was already filled out so I'm going through the equations to see if I yield similar numbers to the results of the first column and I don't. 

In order to find the vapor pressure you need to know the mixing ratio and to find the mixing ratio you need to know the vapor pressure. 

But I can't get their answer of 19.7 

Can't figure out why the big struggle with this...did similar stuff in thermodyanmics or dynamics. But I'm missing something

1 hour ago, CT Rain said:

I definitely have a different take. I thought the intensity forecasts were flat out bad. Not sure they could have done anything different but I certainly did not expect the 3rd most powerful US landfall on record - even 24 hours out!

There's not much they could have done differently though. We suck at intensity forecasting. 

Thankfully this struck a sparsely populated area - but forecast busts with intensity matter and they certainly have the ability to kill. How many people who expected a 4 in NC from Florence and got a cat 1 won't listen next time? 

This is a phenomenal point. I get the fact that at times intensity ratings can be a bit misleading (especially when talking about storm surge/flood potential) but you can't be telling the public to ignore the intensity with one storm and then not ignore it for another storm. There needs to be consistency otherwise the public just gets confused.

Also, when saying to ignore intensity one time and not another could also just be an act to cover up an incorrect forecast. For example, with Florence...many were screaming cat 3/4 for landfall but then when it was obvious that wasn't going to happen those cried...well don't focus on the intensity focus on the other aspects. It was pretty clear Florence wouldn't hit as a major but what was clear was the degree of rainfall that would occur. That should have been harped from the get-go.

10 minutes ago, OceanStWx said:

Most notably shallow, but very warm water. It's also unique because there is land in just about any direction, which can affect storms via friction and dry air entrainment. 

Thanks. 

Pretty much reasons that aren’t to figure out. The shallow but very warm waters makes tremendous sense. Would explain why such rapid intensificatiins can occur when there isn’t anything to inhibit weakening 

5 minutes ago, OceanStWx said:

That's the thing, these GoM TCs can both quickly strengthen and weaken. Definitive forecasts are a tough call there. 

I know there were a few people that maybe weren't forecasting Cat 4, but at least entertained the possibility. I tweeted on Monday that I thought landfall (then projected at 105 knots) was probably more likely to be + or - 15 knots. It looks like +15 was even too conservative. 

What’s the reasons why there are so many uncertainties with intensities within the GoM? 

5 minutes ago, OceanStWx said:

Tide will be incoming at landfall, so overall we're lucky that water levels are low this morning/early afternoon.

Well that’s one piece of good news I suppose 

10 minutes ago, OceanStWx said:

Seriously though, there are no hints of weakening at the moment and probably a fair chance at attaining Category 5 before landfall.

What’s the tide situation like? The storm surge I would think is going to be catastrophic in places. Aren’t some of those places like below sea-level?

5 hours ago, OceanStWx said:

It’s not easy. I’m not aware of any model forecast you can look at. Sometimes you can find a simulation on wx twitter.

gotcha. Thank you.

140 mph    

Just stunned