Visible satellite image of Hurricane Douglas (top left) northwest of Hawaii at 1600Z (8 a.m. Hawaii Standard Time) on Monday, July 27, 2020. (Image credit: RAMMB/CIRA/Colorado State University)

Hurricane Douglas stayed just far enough north of Hawaii’s main islands to spare them from major impacts, but the storm’s place in hurricane history is secure. Douglas is the first hurricane in decades of satellite monitoring to parallel the full length of the islands from Maui to Kauai while staying within striking distance of them. In fact, Douglas’s center passed within 50 miles of several islands.

Fortunately, Douglas was tracking to the north rather than to the south of the islands. That track kept Hawaii on the storm’s weaker left-hand side; even the hurricane’s southern eyewall stayed just offshore. Winds gusted to no more than 33 mph at Lihue and 29 mph at Honolulu. Douglas’s brisk motion and its offshore track also helped keep rainfall amounts modest by hurricane standards. A personal weather station at Laie, on the eastern shore of Oahu, reported 2.37 inches of rain on Monday, and Kapahi, on the eastern shore of Kauai, reported 1.49 inches.

Radar image of Hurricane Douglas at 0334Z Monday, July 27, 2020 (5:38 p.m. Sunday Hawaii Standard Time), as the storm was passing north of Oahu. (Image credit: National Weather Service via Mark Nissenbaum/Florida State University)

A hurricane warning remained in effect Monday for parts of the string of atolls and small islands that make up the Papahānaumokuākea Marine National Monument, which extends hundreds of miles to the northwest of Hawaii’s main islands. At 8 am HST, Douglas remained a Category 1 hurricane with top sustained winds of 90 mph, located about 130 miles northwest of Lihue and chugging west-northwest at 17 mph.

Several hurricanes have been recorded across the marine national monument. The most recent and most notable is Walaka, which moved north through the area in early October 2018. After peaking as a Category 5 storm well southwest of Hawaii, Walaka pushed a powerful storm surge across East Island in the French Frigate Shoals section of the national monument. Walaka’s surge destroyed the 11-acre island that had been a key habitat for Hawaii’s green sea turtles.

Douglas’s survival as a hurricane is in part brought about by above-average sea surface temperatures for this time of year across the Hawaii region (see image below). Tropical cyclones typically rely on sea surface temperatures of at least 79 degrees Fahrenheit (26°C) to provide the heat needed to sustain their core of showers and thunderstorms. Traditionally, sea surface temperatures around Hawaii seldom met this informal threshold, but recent oceanic warming has pushed them above it more often, as was the case with Douglas. Continued warming from human-produced greenhouse gases is expected to make the waters around and southeast of Hawaii increasingly conducive to hurricanes.

Sea surface temperatures (SST) in the central North Pacific Ocean on July 27, 2020 (top, in degrees Celsius) and departure from average SST for this time of year (bottom). (Image credit: Tropical Tidbits)

7/26 Original Post: Douglas to affect much of Hawaii Sunday night as hurricane or strong tropical storm

Infrared satellite image of Hurricane Douglas just northeast of Hawaii at 1655Z (7:55 am Hawaii Standard Time) Sunday, July 26, 2020. (Image credit: tropicaltidbits.com)

One of the most unusual hurricane threats in state history loomed on Sunday, July 26, as Hurricane Douglas raced toward Hawaii. Most hurricanes approaching from the east weaken dramatically or dissipate before they reach the islands, but Douglas may become one of the exceptions that breaks the rule.

At 5 a.m. Hawaii Standard Time (HST) Sunday, Douglas was a top-end Category 1 storm with sustained winds of 90 mph. Located about 145 miles east of Kahului, Douglas was charging west-northwest at roughly 18 mph. NOAA’s Central Pacific Hurricane Center predicted that Douglas would weaken only slightly on Sunday, maintaining hurricane strength (sustained winds of 75 mph or more) as it passes near or just north of the islands from Maui to Kauai between Sunday afternoon and early Monday.

Moderate to strong wind shear of 10 – 20 knots is tilting Douglas to the north with height, but hurricane-hunter flights confirmed that the storm was maintaining its overall integrity. Douglas will pass over progressively warmer waters on Sunday as it nears Hawaii, and that may help counteract the corrosive effects of wind shear.

There is high confidence in Douglas’s overall west-northwest track, and it should be at least a tropical storm throughout its trek near Hawaii, so at least some wind, rain, and surf impacts will be felt. The stronger side of a Northern Hemisphere hurricane is to the right of its direction of motion, so Douglas’s strongest winds will be on its north side, which will most likely dodge most or all of the islands. Hurricane-force sustained winds extend out only about 15 miles on Douglas’s south side.

The precise impacts on Hawaii will hinge largely on subtleties in Douglas’s track. It appears the hurricane may bend slightly westward this evening, and that may bring the worst impacts to Oahu and/or Kauai. Even if Douglas passes just to the north, widespread sustained winds of 40 to 60 mph and rains of 5 to 10 inches could affect any of the islands from Maui to Kauai, with heavier rains and stronger winds possible at higher elevations. These winds could bring down trees and power lines, especially where Douglas’s rains loosen the soil. Some locations could experience winds that are infrequent if not unprecedented. Douglas’s brisk motion should help reduce total rainfall, but flash flooding and mudslides are certainly possible wherever heavy rains strike.

Winds at most locations can be expected to swing from north to west to south as Douglas passes by, although mountains could lead to widely varying wind effects across small areas.

All hurricanes and tropical storms on record that have passed near the Hawaiian Islands, represented here by a 400-mile-wide circle. The only hurricanes on record to make landfall in Hawaii are Dot (1959) and Iniki (1992), both of which struck Kauai. (Image credit: NOAA)

Douglas is a major outlier

Already, Douglas is traveling over oceanic territory just north of the Big Island and east of Maui where no hurricane has been observed in decades of satellite monitoring. The closest analog for strength among west-northwest tracking hurricanes, Lester (2016), passed about 130 miles northeast of Hawaii as a Category 1 storm. Douglas’s forecast track is most similar to that of Flossie (2013), which weakened to tropical depression status before passing just north of Kauai and Oahu.

A number of other systems have passed north of Hawaii as tropical storms or tropical depressions, as shown above. By far the strongest hurricanes to affect Hawaii are those approaching from warmer waters to the south. Category 5 Lane (2018) passed within about 150 miles of the Big Island while still a Category 3. Along with $250 million in damage, Lane dumped 58 inches (1473 mm) of rain on Kahūnā Falls in the Big Island – the second heaviest rainfall on record from a tropical cyclone in any U.S. state, behind the 60.58″ dumped by Hurricane Harvey in 2017 in Texas.

The only two hurricanes to make landfall in Hawaii are Category 1 Dot (1959) and Category 4 Iniki (1992), both of which struck Kauai from the south. The latter caused six deaths and more than $3 billion in damage. Just three other named systems are known to have struck Hawaii as tropical storms, all in the 2010s: Iselle (2014), Big Island; Darby (2016), Big Island; and Olivia (2018), Maui and Lanai.

7/25 update: Hawaii braces for Hurricane Douglas

A study published in May in the Proceedings of the National Academy of Sciences found an increased frequency of tropical cyclones from 1980 to 2018 over a zone extending east and south from Hawaii – including the region that gave birth to Douglas – amid larger-scale trends that could be explained only by factoring in human-induced climate change. “We show for the first time that this observed geographic pattern cannot be explained only by natural variability,” lead author Hiroyuki Murakami said then in a NOAA news release.

For more local detail on the impacts expected from Douglas, see the point-and-click interface provided by the National Weather Service office in Honolulu.

For information on YCC’s “Eye on the Storm,” visit this page. To keep up with news on timing for launch of the blog, sign up for announcements. Got questions? Send an email to EyeOnTheStorm.

Bob Henson

Bob Henson is a meteorologist and journalist based in Boulder, Colorado. He has written on weather and climate for the National Center for Atmospheric Research, Weather Underground, and many freelance...

372 replies on “7/27 update: Douglas earns a place in hurricane history while sparing Hawaii”

  1. <a href=”https://twitter.com/elioeFIN/status/1288207721771270144″>I made an advisory of PTC9</a>

  2. A quick recap of what I’ve learned works for this commenting system.

    We now have basic text features available: bold, italic, spoiler, quote, link, bullet list, etc. &Eacute; &egrave; &Ccedil; &ouml; and other <a href=”http://www.thesauruslex.com/typo/eng/enghtml.htm”>foreign language characters</a> should all function.

    Common HTML code symbols are fine, too. For example, <a href=”http://cactus.io/resources/toolbox/html-arrow-symbol-codes”>HTML arrows</a>: &uarr; &rarr; and a ★ star &deg; Degree symbol &micro;

    I’m fairly certain we still can’t alter text color <font color=”red”>RED</font> <font color=”#0000fe”>BLUE</font> <font color=”rgb(50, 150, 0)”>GREEN</font>

    Both subscript and superscript don’t work.
    But Upside-Down text still does! Just type it into this URL, and paste the results: http://www.upsidedowntext.com/

    For some reason, I couldn’t upload .JPG photos/files. It says “unsupported file type.” Both .gif and .png are proven to work fine. Except the embedded image preview may be small. Dunno why, might need to find the optimal size so it doesn’t auto re-size like that.

    __________

    Here’s my screen cap of this exact comment before posting:

    1. Wow. Okay. That totally failed! Huh.
      What happened? The new commenting now only allows full HTML code, but not HTML entity codes?
      ↑ ↑ &uarr; up arrow
      ℃ ℉ &deg;

  3. <blockquote class="twitter-tweet"><p lang="en" dir="ltr">The Milky Way as seen from a class 2 dark sky site along the Oklahoma/Kansas border. Jupiter and Saturn make an appearance above the abandoned barn, along with some airglow. This was my first real attempt at a Milky Way photo and I am hooked. <a href="https://twitter.com/hashtag/okwx?src=hash&amp;ref_src=twsrc%5Etfw">#okwx</a> <a href="https://twitter.com/hashtag/ksws?src=hash&amp;ref_src=twsrc%5Etfw">#ksws</a> <a href="https://t.co/ZrmBPq1GNP">pic.twitter.com/ZrmBPq1GNP</a></p>&mdash; Alex Spahn (@spahn711) <a href="https://twitter.com/spahn711/status/1287947146793291777?ref_src=twsrc%5Etfw">July 28, 2020</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>
    
  4. TIP: enable Desktop Mode on mobile…
    To see full posts…

    Upper right corner…

    Three vertical dots…

    Works on Android

  5. Unbelievable. The latest EURO is simply unbelievable.

    If the Gulf comes into play with this system, it’d be an absolute game changer.

    1. like, i have a legit wordpress account, but cant get it to log me in here. gonna try logging in on a friends blog and coming back here.

  6. I’m trying to “learn” the habits of this new commenting system. I wonder why it shrunk my 900×540 and 1024×659 pixel photos down to 300×180. I didn’t resize them, it happened automatically upon upload. Huh? I see some others that appear to suffer the same problem. Yet, others have images up to 1050 pixels wide that are close to optimized for embedded viewing here. And why is .jpg format an “unsupported file type?” I’ve only confirmed .gif’s can upload, but now let’s also try a .png file just as a test.

    One thing, it’s tough to track comments when the algorithm could constantly shift comments – based on ‘most reacted’ or ‘hottest thread.’ In one sense, some can get “disappeared” as various comment page views/sorting are loaded or such. So, a fix is to go to the url (address box) and remove all the text after the last “/” of this article, then hit ‘enter.’ That resets the page to newest comments upon refresh.

    Here’s an interesting hot tower cloud, with precip. And quite hard to capture with my camera’s sensor, but this almost horizontal iridescent cloud was a vibrant rainbow of color. I guess from the angle of a nearly setting sun – but only about 50&deg; away. Nothing near the opposite position in the sky and 41&deg; (where rainbows typically form). Really curious. 900×536 pixel .png file.

    1. .png file uploads. But darn, it auto-resized this embedded image preview down to 300×179, too.

      1. Yes, thanks for noticing. But the embedded image is small. And some other commentors have larger-sized image previews. Why? I mean, not that it makes me insecure or anything…

        And curious how all images from the entire comment page can be scrolled thru in sequence when embiggened. Regardless of who posted.

  7. <blockquote class="twitter-tweet"><p lang="en" dir="ltr">Check out these beautiful aerial photos of the Artemis I <a href="https://twitter.com/NASA_SLS?ref_src=twsrc%5Etfw">@NASA_SLS</a> booster segments arriving at <a href="https://twitter.com/NASAKennedy?ref_src=twsrc%5Etfw">@NASAKennedy</a> last month! <a href="https://t.co/klToInY2Gn">pic.twitter.com/klToInY2Gn</a></p>&mdash; NASA's Exploration Ground Systems (@NASAGroundSys) <a href="https://twitter.com/NASAGroundSys/status/1288146621801299968?ref_src=twsrc%5Etfw">July 28, 2020</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>
    
      1. Yeah I’ve tried using code block with a few other sites. No luck yet. That tweet just happened to be the first one on my feed.

  8. TXNT28 KNES 281758
    TCSNTL

    A. 09L (NONAME)

    B. 28/1730Z

    C. 13.3N

    D. 56.2W

    E. FIVE/GOES-E

    F. T1.5/1.5

    G. IR/EIR/VIS

    H. REMARKS…2.5/10 BANDING WAS MEASURED AROUND THE LLCC RESULTING IN
    A DT OF 1.5. THE MET AND PT AGREE AND THE FT IS BASED ON MET, DUE TO
    UNCERTAINTY WITH THE LOCATION OF THE LLCC.

    I. ADDL POSITIONS

    NIL

    …MLEVINE

  9. A lot to figure out still with this one. Track relies a lot on where it actually establishes a center, but some of the models, like the Euro so far today, just show it remaining open for the next few days. If this happens, it could just pass by PR, Hispaniola, and Cuba as a wave. What it does in the Bahamas may ultimately decide what happens with the storm. Until then, it seems like the wave axis is just gonna move through the Greater Antilles, but I’d bet on formation later rather than sooner. Reminds me a lot of Hermine 2016. Forecast to form in the ATL, then struggle north of the islands, but never did anything until it found a sweet spot closer to the US. That’d be the solution I’d lean toward with this one.

    I think something will come out of 9, but exactly when and where is amazingly uncertain, way more than usual.

  10. So glad I found this. Couldn’t find you on WU. Always tune in to this blog during hurricane season. Been a lurker for a long time. 🙂

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