PTC9
Infrared satellite image of Potential Tropical Cyclone Nine (PTC 9) approaching the Lesser Antilles Islands at 11 a.m. EDT Tuesday, July 28, 2020. Superimposed in warm colors are the location of dust and dry air of the Saharan Air Layer (SAL), which lay just to the north of PTC 9. (Image credit: University of Wisconsin.

A large and vigorous tropical wave in the central tropical Atlantic, located about 300 miles east of the Leeward Islands, was designated Potential Tropical Cyclone Nine (PTC 9) by NOAA’s National Hurricane Center (NHC) at 11 a.m. EDT Tuesday, July 28.

PTC 9 had top sustained winds near 40 mph and was headed west at 23 mph. It is predicted to bring tropical storm conditions with heavy rains of 3 – 6 inches to the Leeward Islands, the Virgin Islands, and Puerto Rico on Wednesday. PTC 9’s winds are likely stronger than 40 mph, since an Air Force hurricane hunter aircraft investigating the storm Tuesday afternoon found winds of 60 – 65 mph at 10,000 feet in altitude, which typically implies surface winds near 55 mph.

PTC 9 had favorable conditions for development on Tuesday afternoon, with sea surface temperatures near 28 degrees Celsius (82°F) and moderate light shear of 5 – 10 knots. The system was embedded in a moderately dry atmosphere with a mid-level relative humidity of 60%. Satellite images on Tuesday showed that PTC 9 was large and elongated, with two areas of concentrated heavy thunderstorm activity, one to the west-southwest, and one to the east-northeast. The future track and intensity of PTC 9 will heavily depend upon which of these two areas PTC 9 ends up consolidating around. A more northerly location would likely lead to a stronger storm.

Satellite view
Figure 1. Visible GOES-17 satellite image of PTC 9 at 15:20Z (11:20 a.m. EDT) Tuesday, July 28, 2020. (Image credit: NOAA/RAMMB)

Forecast for PTC 9

As PTC 9 progresses mostly west-northwestward at 15 – 20 mph over the next few days, it will have to contend with dry air from the Saharan Air Layer, located to its north. The 12Z Tuesday run of the SHIPS model predicted that the atmosphere surrounding the system would slowly dry to a relative humidity of 55% by Thursday. However, the model predicted that wind shear would remain light to moderate, 5 – 15 knots, for the remainder of the week, making it feasible for PTC 9 to wall off the dry air to its north and form a strong inner core region of heavy thunderstorms resistant to the dry air.

SSTs will warm to 29 degrees Celsius (84°F) by Thursday, which will aid the intensification process. Also favoring intensification will be a large-scale region of ascending air over the Atlantic, caused by passage of an atmospheric disturbance called a Convectively Coupled Kelvin Wave (CCKW), as explained in a tweet by Michael Ventrice.

Steering currents will likely carry the system very close to Hispaniola on Thursday, and passage close to this mountainous island could significantly disrupt PTC 9’s circulation.

The 11 a.m. EDT Tuesday NHC intensity forecast called for PTC 9 to remain below hurricane strength, peaking with 60 mph winds this weekend. Several of the top intensity models also predicted that PTC 9 would not become a hurricane. However, some models are predicting PTC 9 will be a hurricane this weekend as it moves through the Bahamas and approaches the southeastern U.S. coast. The most startling prediction came from the 12Z Tuesday run of the SHIPS model, which gave a 55% chance that PTC would rapidly intensify by 75 mph in 72 hours. However, PTC 9 would have to get organized in a hurry, becoming a tropical storm on Tuesday, in order for the storm to intensify so quickly.

PHOTO Survivors of Hurricane Maria hand out fruit trees in Puerto Rico

The uncertainty in the future intensity of PTC 9 is very high, but it will be no surprise if it becomes a hurricane late this week.

The three best models for predicting tropical cyclone genesis – the European, GFS, and UKMET models – all support intensification of PTC 9 into a tropical storm by Thursday, July 30. In an 8 a.m. EDT Tuesday Tropical Weather Outlook, NHC gave PTC 9 two-day and five-day odds of formation of 80% and 90%, respectively.

The next name on the Atlantic list of storms is an obscure one, “Isaias” (pronounced ees-ah-EE-ahs). The earliest ninth storm in Atlantic tropical history was Irene on August 7, 2005; The earliest “H” storm prior to Hanna of this year was Harvey on August 3, 2005.

Topics: Weather Extremes
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Redfisher24
Redfisher24
16 days ago

Test 123

Dirk
Dirk
16 days ago

Any one have a guide or something of how to use this comment section ?
Yale perhaps?

stevezonecs
stevezonecs
16 days ago
Reply to  Dirk

I just went to page 14 down at the bottom to get to the newest comments.

Eddie Roye
Eddie Roye
16 days ago

CoC developing 64.7 W & 15.1 N…

85976993 (3).gif
Dirk
Dirk
16 days ago
Reply to  Eddie Roye

Mmmmphff, getting old, i haven´t got a clue of how to use this yet.

Eddie Roye
Eddie Roye
16 days ago

CoC developing near Longitude 64.7 West and Latitude 15.2 North…

Athena
16 days ago

Let’s see if copy image and paste works. (Thanks, Carmot! AWESOME troubleshooting)

Last edited 16 days ago by Athena
JCheeverLoophole42
JCheeverLoophole42
16 days ago

Hooray, the blog is back. We live again. Thank you, Dr Masters (and Yale)..

carmot
carmot
16 days ago

Testing. Because, where would the world be without tests amirite?
Think this will load/embed full-width image preview, yup (“copy image” and paste, not cut ‘n paste image link):

comment image
comment image

carmot
carmot
16 days ago
Reply to  carmot

OH. LQQKIT that. Both worked successfully.
First was copy image and pasted.
Second was copied image’s URL link and pasted.

Okay, now… My bet says this gives only a small/tiny 300px wide thumb preview. That you’d need to click on to view larger. Uploading from my own computer:
First Test: .jpg still says “not supported file type”
Second test is my .gif. Same size/resolution as the above Disqus image from online. Yup. Shrunk.

mRays PMx 02221.gif
Skyepony (mod)
Skyepony (mod)
16 days ago
Reply to  carmot

Still can’t find how to get back to where I could upload images. Can’t find the three dots that Ryan mentions.

bob therriault
bob therriault
16 days ago
Reply to  carmot

Now that is a sunset! Well done, sir.👍

carmot
carmot
16 days ago
Reply to  bob therriault

Thanks. We get crepuscular rays quite often, almost weekly in Saipan. But rarely with so much color in the sky and such dramatic clouds! But my apologies, I just wanted to test image sharing, upload versus one hosted online. Hypothesis proven.

For larger image (embedded) previews, we’ll need to share hosted images. Not from our personal computers. *sigh*

Last edited 16 days ago by carmot
Athena
16 days ago
Reply to  carmot

Just gorgeous!!!!

Dirk
Dirk
16 days ago
Reply to  carmot

One word only : Wowww

DrCane1985
DrCane1985
16 days ago

An absolute game changer on the latest EURO.

DrCane1985
DrCane1985
16 days ago

Oh. My God..

The EURO no longer moves it across Hispaniola, . XD

Lee
Lee
16 days ago
Reply to  DrCane1985

Yeah not good more time over water and its going to slow down just hope it dosent get its act together

Wyatt Washburn
Wyatt Washburn
16 days ago

Some areas in the S.C Upstate are 20 inches above average for rainfall already this year. While we dried out some over the last 30 days, the set up this year’s hurricane season could spell historic flooding issues across the Tennessee Valley, Gulf States, and larger Southeast. With more systems likely getting trapped into the Gulf of Mexico at times this season, these same areas will be at risk. Rain forecast for the next six days in afternoon thunderstorms for my area in the Upstate. More moisture, more energy, more problems in an ever warming climate. Short excellent read on past river flooding in South Carolina below.

An Analysis of Past River Flooding at Select National Weather Service River Forecast Locations in South Carolina Jeff C. Dobur: Significant River Flood Events in Past Years The number of significant river flood events by year from 1975 to 2006 indicated that 1998 had the most significant flood events with the flooding attributed to non-tropical rainfall during that year (Fig. 5). It is noted that most of the flooding occurred during the winter and early spring season at the time of a particular strong El Nino. Further investigation into the Enso affects on river flooding in South Carolina is discussed later in this paper. As far as the most active year for river flooding attributed to tropical storm rainfall, the 1990 tropical season has the greatest number of significant floods. With the combination of Tropical Storm Klaus and Tropical Marco from October 12th through October 14th, rainfall amounts of 5 to 12 inches fell across many locations of the state bringing significant flooding to eight of the 12 locations looked at in this study. Other notable years for tropical storm rainfall and flooding include 1979 with Hurricane David, 1995 with Tropical Storm Jerry and the 2004 season with Frances and Ivan which affected mostly the Upstate. Of the 216 significant river flood events, 186 (86%) were associated with nontropical rainfall weather systems and 30 (14%) were linked to tropical systems. When examining just the tropical season between June 1st and October 31st, the data shows that of the 44 estimated significant river flood events, 29 (66%) were linked to tropical systems and 15 (34%) events were non-tropical weather systems that produced the rainfall leading to the flooding. Significant River F lood Events and the El NiñoSouthern Oscillation (ENSO) Data was examined comparing the significant river flood events that were not associated with tropical systems and the time of the events relative to the phase of the El Niño-Southern Oscillation (ENSO). Results depicted that 60 percent of these significant river floods had occurred during an El Niño phase of the ENSO, with 26 percent during the neutral ENSO phase and 14 percent during the La Niña phase. The 60 percent of significant river flood events during El Niño is especially noteworthy considering the El Niño phase represents only about 20 percent of the time period from January 1975 through December 2006. comment image

micatnight
16 days ago

comment image

Sherman
Sherman
16 days ago

When does the steering around the High pressure come into play?

BioWeather
BioWeather
16 days ago

Just testing.

Ryan Sperrey
Ryan Sperrey
16 days ago

Mobile users, comments may…
Cut Off mid sentence…
Turn on “Desktop Mode”…

On Android, in chrome….
Upper right corner…
Three vertical dots…
Scroll till you see…
Desktop Site, check it…

Enjoy.

Viking1204
Viking1204
16 days ago

Any way to enlarge the number of comments that appear on a page, right now on Page 13 and have to keep checking to make sure it hasn’t moved on to a new page.

carmot
carmot
16 days ago
Reply to  Viking1204

↑ ↑ This! ↑ ↑ Yes please! And basically anything off the most recent page is gone. I mean, hard to track older comments. Or see if anybody’s possibly responded to (my) older comments. Really inhibits any sort of great discussions. *sigh*

galisle
galisle
16 days ago

Test. Long time lurker putting toe in water

micatnight
16 days ago

comment image

Athena
16 days ago

Tried to post a photo… is JPG not supported?

Oh oh… I don’t know how to change formats. Oh well…

micatnight
16 days ago
Reply to  Athena

Try posting an image from your phone. Can’t do it on the pc, but phone good.

micatnight
16 days ago
Reply to  Athena

Or upload to WU then copy image address and post here.

Athena
16 days ago
Reply to  Athena

It says: not allowed file type

Athena
16 days ago
Reply to  Athena

OK, it looks like PNG will work. (Still testing this out).

math puns.png
Shira
Shira
16 days ago
Reply to  Athena

My kind of pun!

Dirk
Dirk
16 days ago
Reply to  Athena

.jpg

carmot
carmot
16 days ago
Reply to  Athena

I’ve had the same issue “unsupported file type.” But one workaround would be as micatnight says below, if you upload it to anywhere hosted online (including to a published Disqus comment), then you can go and click on that image. Copy and paste the link. It will (or *should*) embed in your comment here. AND BIGGER than if you upload an image from your computer. I’ve seen others post .jpg images here that show up to about 1500px wide, with full-sized embedded image previews.

You can also use a freeware program. I use PhotoScape for almost all my photo editing. You can edit there. You can change file types to .jpg, .png, or .gif and then re-save. But again, uploading from your computer will likely embed only a smaller (300px wide) thumb. People have to click to view it larger. Sucks. That’s what happens to my uploaded .gif or .png images. Cheers.

http://www.photoscape.org/ps/main/index.php

Last edited 16 days ago by carmot
micatnight
16 days ago
Reply to  carmot

I haven’t really encountered any problems other than using images from my pc. when posting pics from my phone it looks like they were automatically resized.

Debwrica
Debwrica
16 days ago

Testing! Lurking since 2005 from Florida. I have missed the blog so much!

micatnight
16 days ago

Interesting.
Easier using my phone.

20191102_074257.jpg
micatnight
16 days ago

Sweet.

micatnight
16 days ago

Looks like I can attach an image from my phone but not from my computer.

20200724_200004.jpg
PR100x35
PR100x35
16 days ago
Reply to  micatnight

Nice

5e8f704af3dfa.image.jpg
micatnight
16 days ago

Hello, it’s me, hello. Just testing out my Android phone.

Skyepony (mod)
Skyepony (mod)
16 days ago
Reply to  micatnight

Wonder if I got in phone mode when I switched profiles. Seemed like someone was diuscussion there being different settings.

carmot
carmot
16 days ago
Reply to  Skyepony (mod)

Something about maybe clicking three dots in an upper (right?) corner? For “view in fullscreen mode” or widescreen mode something? I dunno. I cannot handle using my phone for browsing or typing unless absolutely necessary.

Athena
16 days ago
Reply to  micatnight

Does anyone else have that song stuck in their head, now??? Hello, it’s me….

Dirk
Dirk
16 days ago
Reply to  micatnight

Hello you, it´s me 😉

Skyepony (mod)
Skyepony (mod)
16 days ago

NHC Says..
HEAVY RAINFALL AND GUSTY WINDS CONTINUE TO SPREAD OVER THE LEEWARD ISLANDS

Skyepony (mod)
Skyepony (mod)
16 days ago
Reply to  Skyepony (mod)

Had to try it..

carmot
carmot
16 days ago
Reply to  Skyepony (mod)

I much prefer the HTML code “spoiler” because it doesn’t take up so much dang space. Only where you want it, not where ya don’t, ya know? : )

carmot
carmot
16 days ago
Reply to  Skyepony (mod)

Yup. Because where would the world be without testing?
Oh wait… Dang…

sflgatorgirl
sflgatorgirl
16 days ago

So excited to see the blog comments up and running. I wasn’t sure how I would get through a hurricane season without it! Long time lurker of WU.

micatnight
16 days ago
Reply to  sflgatorgirl

If you’re in PBC click on my handle for the HP2020 guide.

stevezonecs
stevezonecs
16 days ago
Reply to  sflgatorgirl

So many of us are…