20W Advisories

...Hagibis weakening further as it edges ever closer to Japan...

Center Track Forecast

INIT 00Z/OCT12 32.0N 137.4E 95KT 110MPH12HR 12Z/OCT12 35.8N 140.0E 80KT 90MPH - Inland24HR 00Z/OCT13 39.7N 143.6E 65KT 75MPH - Transitioning36HR 12Z/OCT13 44.3N 151.3E 55KT 65MPH - Transitioning48HR 00Z/OCT14 50.9N 167.7E 50KT 60MPH - Extratropical

Advisory 7


1-minute sustained wind: 95 knots; 110 mph; 175 km/hEstimated minimum pressure: 937 mbCurrent position: 32.0N 137.4E

Public Advisory

20W, or Hagibis, continues to weaken on approach to Japan, currently with winds estimated at 95 knots, or 110 miles per hour. Landfall is expected within the next 12 hours. Tropical storm-force winds will spread to portions of the eastern coastlines of South Korea over the next 12 hours, with gusts of up to 50 knots (60 mph; 95 km/h) likely on a few areas.

Scientific Discussion

Hagibis is now showing signs of an extratropical transition, with the eye now folding in as evident on IR imagery. Model synthesis is suggesting that the upper level outflow is starting to merge with the upper level trough directly, while the low-level circulation and mid-levels still remain intact. Based on these observations, it will not be long until Hagibis becomes extratropical.
The intensity estimate is set at 95 knots based on SAB and TCD Dvorak estimates of T5/90 knots and a JTWC estimate of T5.5/102 knots. The ADT is estimating CI4.5/77 knots-- SATCON has yet to catch up, so its estimate of 105 knots is not being counted for this advisory.
There is not much left to say for the track forecast as Hagibis moves northward towards the upper level trough. It is expected to complete extratropical transition within the next 48 hours as its warm core disintegrates and becomes directly connected to the trough, while moving northeastward into the Pacific. The center track forecast, per general TCD forecasting routine, stops once the storm has become extratropical. The intensity forecast remains a decay prediction, and does not change mych in comparison to yesterday.

Forecaster ID

MCK

Advisory Archive

Below is an archive of previous advisories for 20W..

...Hagibis approaching Japan...

Center Track Forecast

INIT 00Z/OCT11 27.5N 138.2E 110KT 125MPH12HR 12Z/OCT11 29.3N 137.5E 100KT 115MPH24HR 00Z/OCT12 31.7N 137.2E 90KT 105MPH36HR 12Z/OCT12 34.3N 137.9E 80KT 90MPH48HR 00Z/OCT13 37.5N 141.9E 65KT 75MPH - Transitioning, offshore72HR 00Z/OCT14 45.4N 160.0E 55KT 65MPH - Extratropical

Advisory 6


1-minute sustained wind: 110 knots; 125 mph; 205 km/hEstimated minimum pressure: 923 mbCurrent position: 27.5N 138.2E

Public Advisory

20W, or Hagibis, is currently approaching Japan while weakening, now with winds estimated at 110 knots, or 125 miles per hour. Landfall is expected in Japan within the next 36-48 hours, and the windfield will likely be large enough to induce some storm-force winds in the southeastern coastlines of South Korea.

Scientific Discussion

Hagibis continues to weaken, with the infrared appearance now noticeably deteriorating, with an emerging interaction with a front to the north. Visible satellite appearance shows a cloud-filled eye, and IR data is suggesting a few breaks in the eyewall. The ring has a minimum cloud top of around -60C, further indicative of much-increased weakening. Hagibis is starting to advect some dry air behind the trough. Furthermore, it appears as if the 34-knot wind field is starting to contract slightly, likely in tandem with the weakening winds. The general cloud top-to-eye temperature ratio returns a T-number of 5.7, or 107 knots; the CIMSS ADT is estimating a CI of 5.2/95 knots, and the SATCON is estimating 120 knots, based primarily on microwave estimates. Subjective Dvorak estimates range from CI6/115 knots to CI6.5/127 knots, with FTs ranging from T5/90 knots to T5.5/102 knots. Three ASCAT passes with a resolution of 25 km returned a maximum reading of 70 knots. Based primarily on this, the intensity estimate for this advisory is set at 110 knots.
Hagibis is continuing on a north-northwest path, moving slightly faster than predicted yesterday, now encountering the southwesterly flow from the trough as well as being squarely to the west of a subtropical ridge. Southwesterly flow is expected to increase, lending Hagibis towards a landfall in Japan within the next 36-48 hours. Extratropical transition is expected soon afterwards. Given this, forecast confidence is high today. The intensity forecast mainly follows a regression pattern until extratropical transition, which is expected to complete before the 72 hour mark. As such, the center track forecast stops at 72 hours.

Forecaster ID

MCK

...Hagibis beginning to weaken...

Center Track Forecast

INIT 00Z/OCT10 23.3N 139.8E 135KT 155MPH12HR 12Z/OCT10 25.2N 139.2E 125KT 145MPH24HR 00Z/OCT11 27.3N 138.3E 110KT 125MPH36HR 12Z/OCT11 29.4N 137.5E 100KT 115MPH48HR 00Z/OCT12 31.1N 137.5E 95KT 110MPH72HR 00Z/OCT13 39.0N 143.0E 85KT 100MPH - Transitioning, just offshore96HR 00Z/OCT14 50.9N 162.4E 65KT 75MPH - Extratropical

Advisory 5


1-minute sustained wind: 135 knots; 155 mph; 250 km/hEstimated minimum pressure: 896 mbCurrent position: 23.3N 139.8E

Public Advisory

20W, or Hagibis, is currently weakening, now with winds of 135 knots, or 155 miles per hour. Hagibis is expected to make landfall in Japan with Category 2-equivalent winds, with a windfield large enough to potentially affect Korea and the Kamchatka Peninsula.

Scientific Discussion

Hagibis is now appearing to be in the process of undergoing another eyewall replacement cycle. Alongside this, however, cloud tops have cooled compared to an image from the previous advisory, though the eyewall is starting to become slightly ragged. The storm is beginning to advect a slight layer of stratocumulus clouds to the northwest, which will spell incoming weakening. The trough to the northwest is also now starting to show its effects on the cyclone, with outflow now becoming more poleward, with a blob of thunderstorms to the north of the typhoon. Final-T#s from all Dvorak analysis centers are 6.5/127 knots, though PGTW is holding with a CI of 7.0/140 knots. SATCON is estimating at 141 knots, while the ADT is estimating 132 knots. Given that the RMW is likely expanding slightly, I am setting the advisory intensity estimate at 135 knots. Do note that the pressure is sub-900; this is due to the extremely large size of the typhoon.
The track forecast has changed slightly since the last advisory, with a slight eastward nudge applied to the forecast. The storm has been moving with an average northward movement for the past 6 hours, though trochoidal wobbling is making the true movement difficult to diagnose. Most models continue to depict a slight westward bend, which is expected to be just enough to send Hagibis into a scrape with the Japanese coast while recurving. The chance of a landfall remains high, however, and regardless, strong winds are expected across much of the island due to Hagibis's large size. The intensity forecast is now becoming somewhat straightforward, with the impending eyewall replacement cycle expected to weaken the storm and possibly expose it to the surrounding elements. Shear is expected to exceed 25 knots by the 48 hour mark, and SSTs will dive below the 26C isotherm around that time as well; based primarily on this, extratropical transition is expected beginning at around 48-72 hours. With this in mind, the intensity forecast rides with a blend of the HWRF, GFS, and DSHP models.

Forecaster ID

MCK

...Hagibis on the rebound...

Center Track Forecast

INIT 00Z/OCT09 19.8N 140.3E 140KT 160MPH12HR 12Z/OCT09 21.8N 139.2E 140KT 160MPH24HR 00Z/OCT10 23.7N 138.2E 140KT 160MPH36HR 12Z/OCT10 25.3N 137.6E 135KT 155MPH48HR 00Z/OCT11 27.1N 137.2E 120KT 140MPH72HR 00Z/OCT12 31.5N 138.0E 100KT 115MPH96HR 00Z/OCT13 38.1N 141.7E 85KT 100MPH - Transitioning, just offshore120H 00Z/OCT14 50.0N 158.7E 65KT 75MPH - Extratropical

Advisory 4


1-minute sustained wind: 140 knots; 160 mph; 260 km/hEstimated minimum pressure: 902 mbCurrent position: 19.8N 140.3E

Public Advisory

20W, or Hagibis, is currently restrengthening, now with winds of 140 knots, or 160 miles per hour. Hagibis is expected to make landfall in Japan with Category 2-equivalent winds, with a windfield large enough to potentially affect Korea and the Kamchatka Peninsula.

Scientific Discussion

Hagibis is now rebounding from a fairly rapid eyewall replacement cycle, with a newer, much larger eye now mostly clearing out, surrounded by cloud tops of approximately -82C. There is currently a massive radial outflow spanning more than 20 degrees wide in longitude. The 3-hour trend in satellite imagery is showing that the cloud tops are warming somewhat, with the ADT analysis showing the eye temperature mostly steady at around 15C. Dvorak estimates from PGTW and TCD are at T7.0/140 knots, while SAB submitted a Dvorak analysis of T6.5/127 knots 3 hours ago. The ADT is maintaining a CI of 6.9/137 knots, while SATCON is estimating fairly high at 150 knots, induced mainly by microwave estimates, with a 156-knot AMSU estimate at 12z, an ATMS 155-knot estimate at approximately 15z, and an SSMIS estimate of 155 knots at approximately 22z. Some weight will be given to these estimates, though based on the warming cloud tops I will run slightly lower on the range of estimates, setting it solidly at 140 knots for this advisory.
The long-awaited recurvature has begun, with the forward speed of the TC now slowing to 9 knots, while moving at 320 degrees, or just between NW and NNW. The typhoon is now beginning to round the southwest edge of the subtropical ridge, and will soon come under the direct effects of a trough, which will send it into extratropical transition as the storm moves within proximity of Japan. In terms of the general intensity forecast, there is a 24 hour window for Hagibis to continue strengthening before conditions start lowering the maximum potential intensity-- SSTs are expected to drop to 28C with vertical wind shear beginning to exceed 15 knots. While on approach to the trough, upper level divergence is expected to improve, thus potentially keeping the intensity high. Based on this, I'm running primarily with the CTCX model, which runs on the upper end of the intensity forecast echelon.

Forecaster ID

MCK

...Hagibis weakening, though will likely rebound soon...

Center Track Forecast

INIT 00Z/OCT08 16.9N 143.7E 135KT 155MPH12HR 12Z/OCT08 18.2N 141.4E 140KT 160MPH24HR 00Z/OCT09 19.5N 140.1E 150KT 175MPH36HR 12Z/OCT09 20.3N 139.3E 140KT 160MPH48HR 00Z/OCT10 22.1N 138.5E 130KT 150MPH72HR 00Z/OCT11 25.4N 136.9E 115KT 130MPH96HR 00Z/OCT12 30.0N 136.9E 95KT 110MPH120H 00Z/OCT13 36.5N 140.9E 85KT 100MPH - Just offshore

Advisory 3


1-minute sustained wind: 135 knots; 155 mph; 250 km/hEstimated minimum pressure: 918 mbCurrent position: 16.9N 143.7E

Public Advisory

20W, or Hagibis, is currently weakening, now with winds of 135 knots, or 155 miles per hour. The long-term risk to Japan continues to stand, though it is likely that Hagibis will be of a lower intensity when it comes within proximity.

Scientific Discussion

Hagibis is now in the midst of an eyewall replacement cycle, with its tiny pinhole eye now collapsing into the much larger eyewall structure. This cycle is expected to complete fairly quickly. The ring of cloud tops has warmed quite significantly, with the ring having a minimum full temperature of -79C. Dvorak estimates are T6.5 across the board, with CI7.0 still maintained. Due to the relatively rapid nature of this eyewall replacement cycle, I am setting the estimate at 135 knots for this advisory.
There is no significant change to the track forecast reasoning from yesterday. The intensity forecast calls for further strengthening upon completion of the eyewall replacement cycle, with conditions still primed for a powerful typhoon for the next 24 hours-- SSTs will exceed 29C, with shear below 10 knots for this time. SSTs are expected to decrease afterwards, and the MPI will gradually begin to decrease. Beginning at the 96 hour mark, SSTs will dive while shear increases, marking an extratropical transition possibly starting.

Forecaster ID

MCK

Center Track Forecast

None issued for this advisory.

Advisory 2B


1-minute sustained wind: 150 knots; 175 mph; 280 km/hEstimated minimum pressure: 904 mbCurrent position: 16.3N 145.8E

Scientific Discussion

The purpose of this special advisory is to provide another update to the intensity of Hagibis. TCD came in with a Dvorak estimate of T7.5/155 knots. The CIMSS ADT is now approaching CI7.0, while Raw-T#s have maintained above T7.0 for approximately 12 hours. JTWC and SAB Dvorak estimates are at T7.0, though it should be noted that JTWC and SAB have been using 4km IR data, and the eye is approximately 4-5 km wide, possibly leading to undersampling. As a result, these estimates are being padded to 150 knots.
The next full advisory will be posted tomorrow at approximately 02z. All interests should vigilantly watch the progression of Hagibis.

Forecaster ID

MCK

Center Track Forecast

None issued for this advisory.

Advisory 2A


1-minute sustained wind: 105 knots; 120 mph; 195 km/hEstimated minimum pressure: 950 mbCurrent position: 15.3N 148.9E

Scientific Discussion

The purpose of this special advisory is to update the current intensity estimate of Hagibis. A special Dvorak estimate has come in from the TCD, estimating with a raw Data-T# of 6.0, with a final estimate of T5.5/102 knots. SAB is also estimating T5.5/102 knots, with this estimate being 30 minutes old. Raw T-#s from ADT are currently at 7.2, or equivalent to 146 knots. Based on the continuing improvement in the satellite imagery as well as the larger-than-normal CDO, Hagibis is now raised to 105 knots.
The next full advisory will be posted tomorrow at approximately 02z. All interests should vigilantly watch the progression of Hagibis.

Forecaster ID

MCK

...Hagibis upshifting rapidly...

Center Track Forecast

INIT 00Z/OCT07 15.2N 149.9E 85KT 100MPH12HR 12Z/OCT07 15.9N 146.8E 100KT 115MPH24HR 00Z/OCT08 16.5N 144.6E 115KT 130MPH36HR 12Z/OCT08 17.9N 142.8E 130KT 150MPH48HR 00Z/OCT09 19.9N 141.2E 130KT 150MPH72HR 00Z/OCT10 23.3N 140.0E 125KT 145MPH96HR 00Z/OCT11 25.5N 137.9E 115KT 130MPH120H 00Z/OCT12 30.5N 137.4E 110KT 125MPH

Advisory 2


1-minute sustained wind: 85 knots; 100 mph; 155 km/hEstimated minimum pressure: 968 mbCurrent position: 15.2N 149.9E

Public Advisory

20W, or Hagibis, is rapidly strengthening, now with winds estimated at 85 knots, or 100 miles per hour, making it an increasingly dangerous Category 2 typhoon. A close swipe with the Marianas Islands is expected within the next 24 hours. There is a long-term risk to Japan and potentially the Koreas.

Scientific Discussion

20W is practically scary. The upshifting it has been going through structure-wise is impressive-- at this time an eye-feature is now starting to appear on the IR, with the visual data buffering this appearance as well. The ring of cloud tops are below -80C. Furthermore, there is a dual-inflow structure, with a particularly significant outflow channel buffering an already-radial outflow. SAB came in with T4.0/65 knot estimates at 21z, and TCD came in with a T4.5/77 knot estimate at 2330z. The ADT is holding at just below CI4.0, while the SATCON estimated 82 knots at 2025z-, which may have been sent into a high bias by the CIMSS AMSU, which estimated 111 knots at 1924z. Based on the rapid satellite development I am hedging the estimate mostly with the SATCON, setting this at 85 knots.
There is no significant change to the track forecast logic-- this remains mostly consistent with the previous forecast: a subtropical ridge will provide the primary steering flow until forecast hour 72, before becoming lured towards a poleward path by an encroaching trough. It should be noted that there is quite a bit of uncertainty among the models so as to when the recurvature will occur, with some ensembles even suggesting that the recurvature may not even happen. However, there is a strong-enough faith that this will not occur, and thus I am maintaining the track forecast logic. The intensity forecast logic is not changed much either, with an extremely powerful typhoon still forecast.

Forecaster ID

MCK

...Hagibis strengthening...

Center Track Forecast

INIT 01Z/OCT06 15.0N 155.5E 45KT 50MPH12HR 12Z/OCT06 15.0N 153.0E 60KT 70MPH24HR 00Z/OCT07 15.2N 150.0E 75KT 85MPH36HR 12Z/OCT07 15.9N 146.6E 90KT 100MPH48HR 00Z/OCT08 17.3N 143.4E 105KT 120MPH72HR 00Z/OCT09 18.7N 140.1E 120KT 140MPH96HR 00Z/OCT10 20.6N 138.3E 120KT 140MPH120H 00Z/OCT11 23.3N 136.8E 115KT 130MPH

Advisory 1


1-minute sustained wind: 45 knots; 50 mph; 85 km/hEstimated minimum pressure: 1001 mbCurrent position: 15.0N 155.5E

Public Advisory

20W, or Hagibis, is currently moving west at 16 knots, and is strengthening, with winds of 45 knots, or 50 miles per hour. The storm’s movement will bring it to landfall or through the Marianas Islands within the next 48 hours, likely as a potentially significant tropical cyclone.

Scientific Discussion

20W has coalesced in a fairly frightening manner, with a rapidly developing curveband pattern and expansive, radial outflow. Cloud tops are strong, with minimum readings of -83C being observed on some of the storm cells embedded in the circulation. SAB came in with a Dvorak estimate of T2.5/35 knots 3 hours ago, and TCD analysis came in with a T3/45 knots, mostly in line with the ADT CI2.9/43 knots. SATCON is estimating somewhat high at the moment, with an estimate at 53 knots as of the writing of this advisory. Based on this data, I am setting the advisory intensity at 45 knots.
The current track forecast shows a subtropical ridge providing the primary steering flow for most of the forecast period, with an encroaching trough to gradually add influence, starting the recurvature process after forecast hour 72-96, though a slowdown is expected. The intensity forecast is quite alarming, with environmental conditions being practically primed for a rocket launch of an intensification phase- SSTs of 30C with plentiful ocean-heat content, and upper level synoptic conditions favoring a stronger outflow regime. To start these advisories I am going to follow the middle of the intensity guidance, which already says a lot. Given the somewhat slower movement after forecast hour 72, I will hold off a little with the intensity to account for any potential upwelling as this cyclone could potentially be large.

Forecaster ID

MCK

...Tropical depression forms...

Center Track Forecast

None issued for this advisory.

Advisory P-1


1-minute sustained wind: 25 knots; 30 mph; 45 km/hEstimated minimum pressure: 1006 mbCurrent position: 15.5N 161.0E

Scientific Discussion

Visual satellite data has confirmed the presence of a closed low-level circulation underneath Invest 93W. Microwave data is now showing more organized curvebanding with a potential setup towards a dual-inflow structure. An ASCAT pass captured the western half of the circulation, with winds of 20 knots detected. Based on this data, TCD is upgrading 93W to a tropical depression.
A full advisory will be posted at 00z, October 6. Current model data as well as the evolving microwave imagery increasingly suggests a powerful cyclone will evolve out of 93W. All interests that could be affected should monitor this tropical cyclone for further development.

Forecaster ID

MCK