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2020 Hurricane Season (Atlantic & East Pacific)



  • #2

    Marco, meanwhile, has strengthened unexpectedly and track shifted a bit to the east. Now forecast to become a hurricane within 12h and to remain that way until approaching LA and TX over Monday night.

    A very small storm by TS/Hurricane standards.
    50 KT....... 20NE 20SE 0SW 0NW.
    34 KT....... 40NE 40SE 10SW 30NW.
    12 FT SEAS.. 30NE 30SE 0SW 0NW.
    WTNT44 KNHC 221454

    Tropical Storm Marco Discussion Number 9
    NWS National Hurricane Center Miami FL AL142020
    1000 AM CDT Sat Aug 22 2020

    Reconnaissance data, geostationary and microwave satellite imagery,
    and radar data from Cuba all indicate that Marco is strengthening
    quickly this morning. The Air Force Reserve Hurricane Hunters
    measured a peak 850-mb flight-level wind of 69 kt, and there were
    several SFMR measurements of 50-55 kt to the northeast of the
    center. These data support raising Marco's initial intensity to 55
    kt, and the central pressure based on dropsonde data has fallen to
    992 mb. The crew on the plane reported the formation of a partial
    eyewall, which agrees with what we've seen on recent microwave and
    radar images.

    The track forecast has been complicated by the fact that the plane
    has fixed Marco's center to the east of the previous forecast
    track, and that makes the current motion north-northwestward, or
    340/10 kt. The subtropical ridge currently located over the
    southwestern Atlantic is forecast to build westward along the
    northern Gulf Coast during the next few days, and this expanding
    ridge is expected to push Marco northwestward and then eventually
    westward while the cyclone moves across the Gulf of Mexico. This
    general thinking has not changed, but the adjusted initial position
    ended up shifting the track guidance to the north and east on this
    cycle. In response, the new NHC track forecast has been adjusted
    eastward and northward during the first 3 days and is generally
    between the HCCA and TVCN consensus aids.

    Marco has finally tapped into the favorable conditions over the
    northwestern Caribbean Sea, and the cyclone's overall small size and
    small radius of maximum winds makes it susceptible to quick changes
    in intensity. The tropical storm is just beginning to move into a
    higher zone of shear to its north, but conditions should remain
    conducive enough for Marco to intensity to a hurricane during the
    next 24 hours. After that time, southwesterly shear is expected to
    increase over 20 kt by day 2 and then over 30 kt by day 3, and those
    conditions, along with the cyclone's small size, should cause
    weakening as Marco gets closer to the central and northwestern Gulf
    coast. The updated NHC intensity forecast has been increased during
    the first 2 days and lies above the HCCA/Florida State
    Superensemble solutions but below the SHIPS/LGEM scenarios. The
    intensity forecast comes back in line with the previous forecast by
    day 3 during the expected weakening phase, and Marco is ultimately
    expected to dissipate over Texas by the end of the forecast period.

    The updated track forecast suggests that watches could be required
    for a portion of the central Gulf Coast later today.

    Key Messages:

    1. Marco is forecast to strengthen to a hurricane as it moves into
    the southeastern Gulf of Mexico by tonight, and tropical storm
    conditions are expected over the northeastern coast of the Yucatan
    Peninsula and in extreme western Cuba. Heavy rainfall is also
    expected in the eastern portions of the Mexican states of Quintana
    Roo and Yucatan, and across far western Cuba, which could result in
    flash flooding.

    2. Marco is expected to move across the central Gulf of Mexico as a
    hurricane Sunday and approach the central Gulf Coast on Monday.
    There is an increasing risk of impacts from storm surge, winds, and
    heavy rainfall from the upper Texas coast to Louisiana early next
    week, and interests there should monitor the progress of Marco, as
    storm surge, tropical storm, and/or hurricane watches could be
    issued later today.


    INIT 22/1500Z 20.9N 85.3W 55 KT 65 MPH
    12H 23/0000Z 22.1N 86.0W 65 KT 75 MPH
    24H 23/1200Z 23.9N 87.1W 75 KT 85 MPH
    36H 24/0000Z 25.6N 88.4W 75 KT 85 MPH
    48H 24/1200Z 27.2N 89.9W 70 KT 80 MPH
    60H 25/0000Z 28.5N 91.6W 60 KT 70 MPH
    72H 25/1200Z 29.1N 93.6W 50 KT 60 MPH
    96H 26/1200Z 29.3N 96.6W 35 KT 40 MPH...INLAND
    120H 27/1200Z...DISSIPATED

    Forecaster Berg

  • #2

    Levi Cowan has the possibility of a strengthening Laura (regardless of track) following in behind Marco into Louisiana...

  • #2

    Latest forecasts have Marco and Laura making landfall in different locations, though that could change again. Marco has 12-24 hours to intensify to hurricane strength before shear takes a grip. It may or may not hold onto hurricane status before landfall tomorrow.

    Laura's centre is difficult to locate but in general its track has been shifting further south and west over the past few forecast cycles, meaning a landfall point well to the west of Marco's. It will scoot along the full southern coast of Cuba over the next 36 hours or so, with strengthening to hurricane force expected after that, possibly Cat 2 for a brief while.

    Still a lot of uncertainty with both forecasts.



  • #2

    Marco has now weakened back down to tropical storm of 60 knots, which the NHC say could be generous. Strong shear has taken its toll on it. Even this close to landfall its path is still "maddingly" uncertain, all linked to exactly how its structure changes. It will dissipate quickly over land and looks like being not much of a threat.

    Laura is better organised and is currently at 55 knots as it moves along the full southern coast of Cuba. Guantanamo Bay reported 52 gust 63 knots earlier. It's expected to intensify after it leaves and Cuba and the latrst forecast has it at 90 knots near landfall. Again, still a lot of uncertainty yet.

  • #2

    Will Laura really strengthen in the Gulf so close to Marco having dredged up all the colder waters from the bottom up to the top. Surely Marco will cost Laura a lot of its potential heat pool

  • #2

    Rikand wrote: »
    Will Laura really strengthen in the Gulf so close to Marco having dredged up all the colder waters from the bottom up to the top. Surely Marco will cost Laura a lot of its potential heat pool

    Yes, there is a cool wake from Marco near its future path, though it may not pass directly over it. As Laura will be a larger system than Marco it should be able to weather the storm (so to speak) of that cold pool, especially if its track keeps further west, as it has been doing of late (the latest forecast issued now is south of that shown below).


  • #2

    Meanwhile Marco is disintegrating as we speak and has no chance of being much more than a rain event when it brushes along the Louisiana coast. The strong shear has again taken its toll on an Atlantic system this season. They just can't seem to get going at all, though Laura may break that trend.
    Tropical Storm Marco Discussion Number 16
    NWS National Hurricane Center Miami FL AL142020
    400 AM CDT Mon Aug 24 2020

    Marco is clearly weakening tonight. Data from an Air Force Reserve
    Hurricane Hunter mission showed that flight-level and SFMR had
    decreased along with a substantial rise in central pressure. In
    addition, GOES-16 1-min satellite data show the surface center well
    displaced from the deep convection, and it appears that Marco is
    decoupling from its mid-level circulation to the northeast. The
    initial wind speed is set to 50 kt, and that could be generous.

    Some large changes have been required on this forecast. Considering
    the shear is only forecast to increase, there is no significant
    chance that Marco re-intensifies to a hurricane, and the hurricane
    warnings have been replaced with tropical storm warnings.
    Furthermore, now that the storm is losing vertical coherence, the
    intensity forecast has been decreased as well, and is fairly
    consistent with the model consensus and almost every model.

    Marco has turned northwestward this morning at about 9 kt. The
    storm should gradually turn westward as it approaches southeastern
    Louisiana due to the shallower cyclone feeling the low-level ridge.
    Marco will likely dissipate in a couple of days near the
    Texas/Louisiana border due to continued strong shear. Guidance has
    come into better agreement on the track going slightly inland or
    just brushing the Louisiana coast, and the track has been nudged
    southward on this advisory. It should be noted that the heaviest
    rain and strongest winds will likely be northeast of the center, so
    users should not focus on the exact track of the cyclone.

    Key Messages:

    1. Gusty winds, dangerous storm surge, and heavy rainfall are
    expected from Marco along portions of the Gulf Coast beginning
    later today. Interests in these areas should follow any advice given
    by local government officials.

    2. Tropical Storm Laura could bring additional storm surge,
    rainfall, and wind impacts to portions of the U.S. Gulf Coast by the
    middle of the week. This could result in a prolonged period of
    hazardous weather for areas that may also be affected by Marco.
    Interests there should monitor the progress of Marco and Laura and
    updates to the forecast during the next few days.


    INIT 24/0900Z 27.6N 88.2W 50 KT 60 MPH
    12H 24/1800Z 28.6N 89.2W 45 KT 50 MPH
    24H 25/0600Z 29.2N 90.8W 35 KT 40 MPH...INLAND
    36H 25/1800Z 29.5N 92.7W 30 KT 35 MPH...OVER WATER
    48H 26/0600Z 29.4N 94.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
    60H 26/1800Z...DISSIPATED

  • #2

    Marco's demise has accelerated today and all wind and surge warnings have now been removed. It looks like this year's storms must have a touch of the Covid as they're all failing to produce much of a blow.
    Tropical Storm Marco Special Discussion Number 18
    NWS National Hurricane Center Miami FL AL142020
    100 PM CDT Mon Aug 24 2020

    Marco continues to weaken as the deep convection has been stripped away from the center since this morning. An Air Force Reserve Hurricane Hunter aircraft currently investigating the system has reported peak 925 mb flight level winds of 38 kt. Although there have been a few recent higher SFMR measurements that are due to rain contamination, a recent ASCAT overpass revealed only a small area of 30-35 kt winds. Based on these data the initial intensity is being lowered to 35 kt and a special advisory has been issued to update the short-term intensity forecast and discontinue warnings for the Gulf coast.

    The showers and thunderstorms generating the tropical storm force winds to the northeast of Marco's center are forecast by most models to gradually dissipate through this evening. Based on how quickly the vortex has been spinning down and the anticipated decrease of convection, it is reasonable to assume that sustained tropical storm force winds will no longer reach the northern Gulf coast. Therefore, all wind and surge warnings for the Gulf coast associated with Marco have been discontinued. Shortly after the cyclone reaches the Gulf Coast later tonight it should degenerate to a remnant low, with this low dissipating inland within a couple of days. The latest intensity forecast was adjusted downward through 12 h, but remains the same as the previous NHC forecast thereafter.

    Marco has been moving slowly all day, and an initial motion estimate is now 320/5 kt. There is no change to the forecast track reasoning. As the cyclone continues to weaken and degenerates to a remnant low, a turn to the west-northwest is expected as the system becomes steered in the low level flow. The latest forecast track was adjusted slightly northward through 12 h, but remains the same as the previous one until the system dissipates.

    This special advisory package replaces the 100 PM CDT (1800 UTC)
    intermediate public advisory.

    Key Messages:

    1. Gusty winds, heavy rainfall, and lingering coastal flooding are expected from Marco along portions of the Gulf Coast through this evening. For information on these hazards see products from your local National Weather Service office.

    2. Tropical Storm Laura could bring dangerous storm surge, rainfall, and wind impacts to portions of the U.S. Gulf Coast by the middle of the week, and tropical cyclone wind and surge watches and warnings could be issued for portions of the U.S. Gulf Coast later today.


    INIT 24/1800Z 28.7N 88.6W 35 KT 40 MPH
    12H 25/0000Z 29.4N 89.3W 30 KT 35 MPH...INLAND
    24H 25/1200Z 30.0N 91.3W 30 KT 35 MPH...POST-TROP/REMNT LOW
    36H 26/0000Z 30.5N 93.6W 30 KT 35 MPH...POST-TROP/REMNT LOW
    48H 26/1200Z 30.9N 95.9W 25 KT 30 MPH...POST-TROP/REMNT LOW
    60H 27/0000Z...DISSIPATED

  • #2

    Laura is still just enough off the south Cuban coast to keep it together a bit and produce 50-knot max winds now. It should reach 90 knots (Cat 2) before landfall, though there is still a lot of Cuba to deal with before then.
    Tropical Storm Laura Discussion Number 19
    NWS National Hurricane Center Miami FL AL132020
    1100 AM EDT Mon Aug 24 2020

    Laura's satellite presentation has degraded somewhat since yesterday, however, there has been a recent increase in convection near the center, and a large band over the southern periphery of the circulation. It appears that the combination of land interaction, moderate northerly shear, and some dry air has caused the change in structure. NOAA and Air Force reconnaissance aircraft have reported several believable SFMR winds in the 45-50 kt range and a minimum pressure of around 1002 kt. Based on these observations, the initial wind speed has been set at 50 kt.

    Laura is forecast to pass over the very warm water of the extreme northwestern Caribbean Sea just south of the coast of Cuba today, and some modest strengthening is possible before the center moves over the western portion of Cuba this evening. Laura is then
    forecast to emerge over the southeastern Gulf of Mexico overnight where a combination of warm sea surface temperatures and a favorable upper-level environment are expected to allow for steady strengthening. Given the very conducive upper-level wind pattern depicted by the global models, a period of rapid strengthening is possible once Laura re-organizes an inner core after its passage over western Cuba. The regional hurricane models remain quite bullish on intensification, and the GFS and UKMET models indicate significant deepening while Laura moves over the Gulf of Mexico. The statistical guidance is not as aggressive, and the NHC forecast is in good agreement with the intensity consensus aids which lie between the higher solutions of the regional models and the SHIPS and LGEM guidance.

    Laura has been moving on a steady west-northwestward track over the past day or so, and the initial motion estimate is 285/17 kt. The
    deep-layer ridge over the western Atlantic is forecast to build westward over the eastern Gulf of Mexico during the next day or so, and this should keep Laura on a west-northwestward heading through Tuesday. After that time, a mid- to upper-level trough over the
    south-central United States should produce a break in the ridge over the western Gulf of Mexico. Laura should turn northwestward
    Tuesday night in response to the break in the ridge, and the storm is expected to reach the northwestern Gulf coast Wednesday night.
    The cyclone should become embedded within the mid-latitude westerlies by day 4, and Laura or its remnants should recurve to
    the northeast and east-northeast by the end of the period. Although the track guidance is in somewhat better agreement today,
    there remains some cross-track spread by day 3, with the UKMET showing landfall well southwest of the official forecast. The NHC
    track is close to the various consensus aids and leans toward the typically reliable GFS and ECMWF models.

    Users are again reminded to not to focus on the exact details of the track or intensity forecasts as the average NHC track error at 72 h is around 100 miles and the average intensity error is around 15 mph (13 kt). In addition, wind, storm surge, and rainfall hazards will extend far from the center.

    Key Messages:

    1. Tropical storm conditions are expected across much of Cuba today. Heavy rainfall is likely across Cuba and Jamaica today, and these rains could cause mudslides and life-threatening flash and urban flooding. Tropical storm conditions are expected in the Dry Tortugas, and the Middle and Lower Florida Keys later today.

    2. There is an increasing risk of dangerous storm surge, wind, and rainfall impacts from the upper Texas coast through the north- central Gulf Coast beginning on Wednesday. Interests in these areas should monitor the progress of Laura and ensure they have their hurricane plan in place, as storm surge and hurricane watches will likely be issued later today.


    INIT 24/1500Z 21.2N 80.6W 50 KT 60 MPH
    12H 25/0000Z 22.2N 82.9W 55 KT 65 MPH
    24H 25/1200Z 23.6N 86.0W 60 KT 70 MPH
    36H 26/0000Z 25.2N 88.8W 70 KT 80 MPH
    48H 26/1200Z 26.8N 91.1W 80 KT 90 MPH
    60H 27/0000Z 28.7N 92.8W 90 KT 105 MPH
    72H 27/1200Z 31.2N 93.3W 65 KT 75 MPH...INLAND
    96H 28/1200Z 36.0N 90.9W 30 KT 35 MPH...INLAND
    120H 29/1200Z 37.5N 81.0W 25 KT 30 MPH...POST-TROP/REMNT LOW

  • #2

    Marco has now dissipated to a remnant depression and the NHC have issued their final advisory on it.

    Laura is still 55 knots but is expected to intensify quickly over the next day or so and could hit the TX/LA border as a Cat 3, the first major hurricane of the season. Still a question over exactly how much shear will increase prior to landfall so its exact intensity is still uncertain, but westward corrections to its track have been made and could be required later. That would bring it dangerously close to Houston...
    Tropical Storm Laura Discussion Number 22
    NWS National Hurricane Center Miami FL AL132020
    400 AM CDT Tue Aug 25 2020

    Satellite images show that Laura is becoming better organized. Now that the center is clear from Cuba, very deep convection has developed into a ragged, pulsing central dense overcast, with a large curved band on the southern side of the circulation. The intensity is kept at 55 kt, matching the satellite estimates and a blend of the earlier flight-level and SFMR reconnaissance data. Hurricane Hunter missions from both the Air Force and NOAA should be in the storm within a couple hours to help obtain a new estimate.

    After a westward jog earlier, Laura is estimated to be moving west-northwestward again or 290/15. The synoptic situation consists over a large ridge near the southeastern United States and a weakness in the ridge over Central Texas due to an inverted trough. Laura should gradually gain latitude and turn to the northwest and north-northwest over the next two days while it is steered between those two features, move northward late this week through the southern United States, then move quickly eastward across the eastern U.S. over the weekend as it encounters the mid-latitude westerlies. The majority of the guidance has shifted a notable distance to the west on this run, perhaps due to a weaker trough over Texas and a more westward initial position of Laura (possibly due to persistent northerly mid-level shear). The new NHC prediction is at the eastern edge of the new guidance envelope since I don't want to bite off on such a large change on just one set of model runs. But since the storm has been tracking west of forecast expectations for quite some time, future westward track adjustments could be required later today.

    Laura is forecast to move over the very warm and deep waters of the Gulf of Mexico, with similar or lighter shear conditions through the next couple of days. Now that an inner core appears to be trying to form, conditions appear ripe for at least steady intensification, and rapid intensification is becoming more likely before landfall. In fact, almost all of the explicit guidance models, save the statistical-dynamical models, are showing a period of rapid strengthening at some point during the next couple of days. Thus, the new NHC forecast is higher than the last one, but not as high as the most of the regional hurricane models since shear could increase just before landfall.

    Users are again reminded not to focus on the exact details of the track or intensity forecasts as the average NHC track error at 48 h
    is around 80 miles and the average intensity error is close to 15 mph. In addition, wind, storm surge, and rainfall hazards will extend far from the center.

    Key Messages:

    1. Laura is forecast to reach the northwestern Gulf Coast as a hurricane late Wednesday and early Thursday. Do not focus on the details of the official forecast given the typical uncertainty in NHC's 2-to-3 day track and intensity predictions. In addition, storm surge, wind, and rainfall hazards will extend well away from Laura's center along the Gulf Coast.

    2. There is a risk of life-threatening storm surge from San Luis Pass, Texas, to Ocean Springs, Mississippi, within the next 48
    hours, and a storm surge watch is in effect for these areas outside of the southeast Louisiana Hurricane and Storm Damage Risk
    Reduction System. Residents in these areas should follow any advice given by local officials.

    3. Hurricane conditions are possible by late Wednesday from San Luis Pass, Texas, to west of Morgan City, Louisiana, with tropical storm conditions possible by Wednesday afternoon, and a hurricane watch is in effect. Hurricane Warnings will likely be issued for a portion of that area later today.

    4. The threat of widespread flash and urban flooding, along with small streams overflowing their banks, will be increasing Wednesday night into Thursday from far eastern Texas, across Louisiana, and Arkansas. This will also lead to minor-to-isolated moderate river flooding. The heavy rainfall threat will spread northeastward into the middle-Mississippi, lower Ohio and Tennessee Valleys Friday and


    INIT 25/0900Z 22.9N 85.7W 55 KT 65 MPH
    12H 25/1800Z 23.8N 87.9W 65 KT 75 MPH
    24H 26/0600Z 25.1N 90.6W 80 KT 90 MPH
    36H 26/1800Z 26.8N 92.7W 95 KT 110 MPH
    48H 27/0600Z 29.3N 93.7W 100 KT 115 MPH
    60H 27/1800Z 32.1N 93.7W 55 KT 65 MPH...INLAND
    72H 28/0600Z 34.5N 93.0W 30 KT 35 MPH...INLAND
    96H 29/0600Z 37.0N 86.5W 25 KT 30 MPH...INLAND
    120H 30/0600Z 39.0N 73.0W 40 KT 45 MPH...POST-TROP/EXTRATROP

  • #2

    Hurricane Laura.
    Hurricane Laura Tropical Cyclone Update
    NWS National Hurricane Center Miami FL AL132020
    715 AM CDT Tue Aug 25 2020


    NOAA hurricane hunter aircraft data indicate that Laura has become
    a hurricane with maximum sustained winds of 75 mph (120 km/h), with
    higher gusts.

    LOCATION...23.4N 86.4W

    Forecaster Beven

  • #2

    A lot of model consensus for a Category 3 Laura landfall starting to emerge, with some models even calling for Category 4. Potential for some explosive intensification overnight once she manages to close off the current dry air intrusion. Shear has, as predicted, dropped massively in the Gulf over the last 24 hours.

  • #2

    The latest forecast has it a solid CAT 3 (105 kt) at landfall, which is now slightly further east again, away from Houston.

  • #2

    “Hurricane #Laura Advisory 26: Laura Expected to Rapidly Strengthen to a Category 4 Hurricane. Forecast to Produce a Life-Threatening Storm Surge, Extreme Winds, and Flash Flooding Over Eastern Texas and Louisiana Later Today.”

  • #2

    Winds to 110mph now

  • #2

    When is it due to hit land hope everyone will be safe.

  • #2

    With the RNC at the moment taking all the media fuel, I wonder if this will catch people unaware with the rapid late intensification and first major hurricane of the year.

  • #2

    dfx- wrote: »
    With the RNC at the moment taking all the media fuel, I wonder if this will catch people unaware with the rapid late intensification and first major hurricane of the year.

    Well maybe nationally but you’d assume that local TV in the area would be blinking red and imploring people to take what they need to do.

  • #2

    Expected to reach CAT 4 but then to weaken slightly to CAT 3 (105 kt) before landfall, based on latest forecast.

  • #2

    Reported down to 961mb extrapolated


  • #2

    Update at 12Z has it at 100 knots (Cat 3).

  • #2

    Latest update has it at 125mph now

  • #2

    20 foot storm surge predicted.

  • #2

    Major Hurricane Laura is still strengthening. "unsurvivable storm sturge" near the Texas-Louisiana border.

    LOCATION...27.0N 92.0W
    With Covid-19 restrictions, it's more difficult to accomodate people and people may be less willing to cooperate with evacuation orders. The storm surge potential combined with flash flood risk is a major threat to people and property.

  • #2

    Of all 14 named systems this season this is the first to finally form a proper eye. It's turned into a real beast. Good to have some slight weakening before landfall, as at that speed every 10 knots count energywise.

  • #2

    for something that was modelled to fizzle out and disorganised until Puerto Rico. Then it goes straight over the high southern mountains of Haiti and Cuba, it is a remarkable storm...

  • #2

    Never seen NHC use the term "unsurvivable" before. Think maybe they feel this one has crept up on them as it was a TS for so long and now within <24hrs it's gone from that to Cat 4.
    Remarkable explosive cyclogenesis.
    igCorcaigh wrote: »
    20 foot storm surge predicted.

    Imagine 6 metres of water in your garden. That's the height of most semi-detached houses (to the peak of the roof, too).

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