Sunday, June 07, 2020

TS Cristobal: June 6, Update A

In this day and age, a tinsy bit of good news for those of you in Louisiana and the northern-central Gulf watching TS Cristobal.

Today was the day when we knew we'd find out whether the dry air in the western Gulf would keep Cristobal in check, or whether crossing the deeper warm water in the Gulf would give him the strength to grow. Well... it looks like the dry air is winning that particular argument! Hurray!

He is currently at 26.2N, 90.2W, heading N at a respectable tropical storm speed of 12 mph:

Winds are 50mph, central pressure is 993mb, which makes him currently a weak-to-mid level storm (TS range: 39-74mph). 

As a reminder, the patch of really warm deep water is what he has been crossing today, and is shown by the yellow bit in the middle of the Gulf in this image: 

We can actually see the impact that crossing has on him in the this satellite imagery, which shows that the convection has increased close to the center of circulation (the part that is over the deeper warmer water): 

You can also see the strong convection on the eastern side of the Gulf - over Florida. Technology is so great, that even though I live in Los Angeles, my phone told me that there was a tornado warning in Pinellas County in Florida today... I did see a video of a large tornado/waterspout near Orlando today.

For TS Cristobal's overall development, the dry air has been just too much and is inhibiting him from becoming something bigger: 

After he has crossed that patch of warm and deep water, it doesn't look like he'll intensify too much more, so maximum winds of around 60mph is probably about right. 

But he is going to make landfall to the west of the Mississippi delta, which means he will be pushing water upstream, so be prepared for some storm surge. 

<Technical Alert!> If you want to see the winds and other data as he moves into the northern Gulf, you can check out the Gulf of Mexico Coastal Ocean Observing System (GCOOS) data portal website - this includes moorings and platforms which are measuring real-time data. This Coastal Ocean Observing System is one of 11 around the US - all great resources for data offshore! <End Technical Alert!>

I clicked on a mooring in the middle of the Gulf (just north of the text 'Gulf of Mexico') which shows that the maximum winds at that location were 17 meters/second, which is 38mph - so not quite Tropical Storm winds at that particular location (alas, I don't think there is an easy toggle to make it into mph, but just multiply the m/s by ~2 to get the mph... or use google :-)) and we can see that the storm has just passed by because the pressure dropped and is now rising again: 

<Technical Alert!> And to check storm surge, I go to NOAA's Tides & Currents website: Click on the state you are interested in, and then the area within that state that you want to see the storm surge for. You will see a number of 'pins' - if you hover over one, it will give you the location of the tide gauge. Click on that, and in the bottom left of the pop-up window, you will see a 'plot data' box. Click on that, and it will show you the data - depending on where you chose, you can see the predicted water level for the time of day, and the actual water level. The difference between these two is the storm surge. These plots may also include wind speed, water temperature, air temperature, and air pressure. Lots of useful data! &lt'End Technical Alert!>

I chose to zoom in on New Canal Station in Louisiana - a little way up the Mississippi river, near New Orleans, which is showing water levels of 1.77 ft above expected water levels:
&lt!Jargon Alert!> You may notice that there is a number at the top of this figure - 2.29ft above MLLW. MLLW stands for Mean Low Level Water - this is the lower of the two tides per day at this location, averaged over a 19 year time period. So, for our practical purposes and for anyone who lives in an area, it's not very user-friendly. This is why I prefer to compare the predicted level with the actual level, and in this case it is 1.77 ft. And don't even get me started on the sea level benchmarks that various data are compared against or presented against - it's all over the place! <End Jargon Alert!>

Well, I think that's it for today... must be a weekend. Two Technical Alerts and one Jargon Alert! You guys are SO lucky. ;-)

I'll pop back in tomorrow - when this one will make landfall. 

Be safe out there - listen to your local emergency managers because each area is different! 

Oh, and remember, for all Tropical Storms - hide from the wind, run from the water. This means that if you can shelter safely and you aren't in a flood zone, then stay in place. If you are in a flood zone, then get out. Water causes the most fatalities in tropical storms. 

Oh, and remember to eat the ice cream first in case the power does go out.... 

Ciao for now!

Twitter: jyovianstorm
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and local weather service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know. 

No comments: