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2019 Atlantic Hurricane Season

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  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    NHK have reported the highest gust was 209 kph at Chiba and the highest rainfall total so far of 430 mm in 12 hours in some other place.


  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    INVEST 94L could become depression over the next few days, but what happens after that is anyone's guess.

    Live charts

    94L_geps_latest.png

    94L_intensity_latest.png


  • Registered Users Posts: 6,235 ✭✭✭Oneiric 3


    Latest model run keeping it a relatively tame feature, but as we know, nothing can be ruled out yet.

    Prep total chart up to 0z Sun, gives a rough idea as to where the worst impacts are forecast to occur.

    tJPWMdz.png

    Not great news at all for the regions already battered by Dorian, but could be a lot worse.. and hopefully it won't end up being so.

    Latest from NOAA:

    Tropical Weather Outlook
    NWS National Hurricane Center Miami FL
    800 AM EDT Thu Sep 12 2019

    For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

    1. Satellite images indicate that the area of disturbed weather over
    the central and southeastern Bahamas is gradually becoming better
    organized while surface pressures are falling in the area.
    Conditions are becoming favorable for a tropical depression or a
    tropical storm to form within the next day or so as the system moves
    toward the northwest through the northwestern Bahamas and toward
    the Florida Peninsula at 5 to 10 mph. If this development trend
    continues Potential Tropical Cyclone advisories will likely be
    initiated later today. This disturbance will bring heavy rainfall
    and gusty winds across portions of the Bahamas through Friday,
    especially in portions of the northwestern Bahamas affected by
    Hurricane Dorian. An Air Force Reserve reconnaissance aircraft is
    scheduled to investigate the system this afternoon, if necessary.
    * Formation chance through 48 hours...high...70 percent.
    * Formation chance through 5 days...high...80 percent.

    New Moon



  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir




  • Registered Users Posts: 6,235 ✭✭✭Oneiric 3


    Just watched a good discussion from Tropical Tidbits on this pretty complex feature:

    New Moon



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  • Registered Users Posts: 6,235 ✭✭✭Oneiric 3


    Still seems to be a lot of uncertainty regarding the track and intensity of this storm, of which Jack Sillin (weather.us) discusses here:

    https://blog.weather.us/ptc-9-likely-to-slowly-develop-as-it-approaches-florida-this-weekend/

    General consensus seems to be that it will intensify once it has cleared north of the Bahamas. NOAA has an 80% chance it will develop into a TS within 48 hours, and 90% within 5 days.

    https://www.nhc.noaa.gov/gtwo.php?basin=atlc&fdays=2

    New Moon



  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Humberto should be named overnight. The track is well further east now, missing the US but now aiming right at Bermuda. As a result of its more easterly track the intensity guidance has been trending upwards too throughout the day. Bermuda could get interesting next week.

    aal09_2019091318_track_early.png

    aal09_2019091318_intensity_early.png

    2019AL09_OHCNFCST_201909131800.GIF


  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Humberto is still struggling to develop any real structure, with sporadic deep convection popping up in different sectors. The latest microwave pass shows it to the southeast and east of the centre.

    Latest track has it passing around 73 NM from Bermuda, however it will be over lower ocean heat content and increasing shear by then so it looks like maxing out at Cat 1 or maybe 2..

    20190914.0853.f16.x.pct.09LHUMBERTO.35kts-1007mb-259N-757W.067pc.jpg

    20190914.0853.f16.x.color37.09LHUMBERTO.35kts-1007mb-259N-757W.069pc.jpg

    al092019.19091400.gif


  • Registered Users Posts: 6,235 ✭✭✭Oneiric 3


    Latest models have it passing close to the N of Bermuda and still potentially quite dangerous for the region:

    5lQPKcC.png

    Long way off though but all eyes on.

    New Moon



  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Humberto's intensified well in the last couple of hours, with an eye starting to form on microwave imagery at 1706Z. Aircraft data just now found the central pressure down below 990 hPa and max SFMR winds of 59 knots. It'll probably be upgraded to hurricane by the 10 pm update.

    20190915.1706.gpm.x.color36.09LHUMBERTO.55kts-997mb-286N-778W.039pc.jpg


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  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Nope, it's still just under hurricane-status in their latest update just now.

    Humberto's convective structure continues to improve in satellite imagery and reflectivity data from the Melbourne NOAA Doppler weather radar, including intermittent appearances of a closed eye. An Air Force Reserve reconnaissance aircraft investigating Humberto this afternoon found SFMR winds of 58-59 kt in the northeastern quadrant outside of the heaviest rain areas, and that the pressure had fallen 4 mb during the past 2 hours, now down to 989 mb. Based on these data, the intensity has been increased to 60 kt.

    The initial motion estimate is now 360/05 kt. There are no significant changes to the previous forecast track or reasoning. Humberto is likely located on or near an east-west oriented ridge axis, and a sharp turn toward the northeast is likely during the next 6-12 hours. The latest NHC model guidance remains highly convergent on the previous forecast track and continues to show the cyclone gradually being accelerated toward the northeast and
    east-northeast during the 24-120 hour period. The large deep-layer trough and associated cold front that will be digging southward out of eastern Canada and the northeastern United States is forecast by the ECMWF model to develop a cutoff low over the northwestern Atlantic that results in some binary interaction with Humberto on day 5. However, this is a new development and is considered to be an outlier scenario at this time. The new forecast track is similar to the previous advisory and lies close to the TVCN and HCCA consensus track models.

    Likewise, there is no significant change to previous intensity forecast. All of the available model guidance continues to support steady strengthening for the 3 days. In 48-72 hours, Humberto is forecast to be moving into the right-rear quadrant of a strong, anticyclonically curved 300-200 mb jet maximum. The associated strong baroclinic/dynamical forcing is expected to produce strong pressure falls and strengthening despite the hostile vertical wind shear conditions of at least 30 kt. On days 4 and 5, the combination of slightly cooler waters, drier and more stable air, and much stronger vertical shear of 40-50 kt should cause steady weakening despite the favorable jetstream dynamics. The previous NHC intensity forecast remains unchanged, and continues to show Humberto reaching its peak intensity in 72 hours, coincident with the warmest sea-surface temperatures and strongest jetstream dynamical forcing.

    Large swells from Humberto will affect portions of the northwestern Bahamas and southeastern United States coast during the next few days. These swells are expected to produce dangerous surf conditions and life-threatening rip currents. See products issued by your local weather office for additional information.

    FORECAST POSITIONS AND MAX WINDS

    INIT 15/2100Z 29.3N 78.0W 60 KT 70 MPH
    12H 16/0600Z 29.8N 77.6W 65 KT 75 MPH
    24H 16/1800Z 30.1N 76.7W 70 KT 80 MPH
    36H 17/0600Z 30.4N 75.4W 80 KT 90 MPH
    48H 17/1800Z 30.7N 73.6W 85 KT 100 MPH
    72H 18/1800Z 31.7N 68.9W 95 KT 110 MPH
    96H 19/1800Z 35.0N 62.0W 85 KT 100 MPH
    120H 20/1800Z 39.6N 56.1W 60 KT 70 MPH


  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Pressure's dropped further now, down to 987 hPa.


  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Humberto is just about a hurricane now at 65 kts, 988 hPa. Still a bit of dry air spiralling in from the southwest but an eye should form soon. The latest track still has it passing 70 NM from Bermuda at its closest point, so they will dodge the bullet.

    20190916.0300.goes15.x.wv1km.09LHUMBERTO.65kts-988mb-293N-778W.100pc.jpg

    al092019.19091518.gif


  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Latest recon data 977 hPa, max FL wind 86 kts, max SFMR surface wind 73 kts .


  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Northern hemisphere tropical stats show things are slow to get going this year. The Atlantic is bang on the average, but the Pacific is well below. Only the North Indian ocean is up, due to Fani back in May.

    http://tropical.atmos.colostate.edu/Realtime/


    490768.JPG


  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Nice Terra satellite image of Humberto and the Bahamas this evening.

    https://go.nasa.gov/31uRA8y

    48745969957_1bd775a12a_b.jpg


  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Tropical Storm Imelda formed literally just as it was making landfall in SW Texas a few minutes ago.

    1245 PM CDT Tue Sep 17 2019

    ...DEPRESSION BECOMES TROPICAL STORM IMELDA...

    Surface observations indicate that the depression has strengthened
    as it nears the coast and has become Tropical Storm Imelda, with
    maximum sustained winds near 40 mph (65 km/h). A National Ocean
    Service observing site at Freeport, Texas, recently reported a
    sustained wind of 40 mph (65 km/h) and a wind gust of 47 mph (76
    km/h).


    SUMMARY OF 1245 PM CDT...1745 UTC...INFORMATION
    LOCATION...28.9N 95.3W
    ABOUT 0 MI...0 KM S OF FREEPORT TEXAS
    ABOUT 40 MI...65 KM SW OF GALVESTON TEXAS
    MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
    PRESENT MOVEMENT...N OR 5 DEGREES AT 7 MPH...11 KM/H
    MINIMUM CENTRAL PRESSURE...1009 MB...29.80 INCHES
    130 PM CDT Tue Sep 17 2019

    ...TROPICAL STORM IMELDA MAKES LANDFALL NEAR FREEPORT TEXAS...
    ...HEAVY RAINFALL AND THREAT OF FLASH FLOODING WILL SPREAD INLAND...

    NOAA Doppler radar data and surface observations indicate that
    Tropical Storm Imelda made landfall near Freeport, Texas at
    100 PM CDT with maximum sustained winds of 40 mph.

    A National Ocean Service observing site at Freeport, Texas reported
    a minimum pressure near 1005 mb (29.68 inches) around the time of
    landfall.

    SUMMARY OF 130 PM CDT...1830 UTC...INFORMATION
    LOCATION...29.0N 95.3W
    ABOUT 0 MI...0 KM S OF FREEPORT TEXAS
    ABOUT 35 MI...55 KM SW OF GALVESTON TEXAS
    MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
    PRESENT MOVEMENT...N OR 5 DEGREES AT 7 MPH...11 KM/H
    MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES


  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Latest discussion on Imelda.
    Tropical Storm Imelda Discussion Number 2
    NWS National Hurricane Center Miami FL AL112019
    400 PM CDT Tue Sep 17 2019

    Shortly after the earlier NHC Special Advisory, the cyclone quickly
    intensified just before it made landfall near Freeport, Texas
    around 1800 UTC. A National Ocean Service observing site near
    Freeport, Texas, reported sustained winds of 35 kt with a gust to
    41 kt, and a minimum pressure of 1005.6 mb. A Weatherflow station
    at Surfside Beach also measured sustained winds of 35 kt with a gust
    to 44 kt. The advisory intensity is set at 35 kt based on recent
    Doppler velocities within some of the rain bands that are still
    offshore.

    Imelda joins a list of several systems in the northwestern Gulf of
    Mexico that formed and intensified very near the Texas coast. Other
    recent examples include Allison in 2001 and Humberto in 2007.
    Thankfully, in this case Imelda made landfall before significant
    strengthening could occur. Now that the center is moving inland,
    gradual weakening is expected. It cannot be stressed enough,
    however, that the primary threat from Imelda remains very heavy
    rainfall and life-threatening flash flooding that will spread
    northward into eastern Texas and portions of western Louisiana
    during the next day or so.

    Imelda is moving northward at about 6 kt. The cyclone should
    continue to move slowly northward to north-northwestward around the
    western side of a mid-level ridge over the Tennessee Valley until
    dissipation occurs in a couple of days. The updated NHC track
    forecast has been nudged eastward but remains near the center of the
    tightly clustered track guidance.

    Key Messages:

    1. This system is likely to produce life-threatening flash flooding
    along portions of the Upper Texas Coast, including the Houston and
    Galveston areas.


  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Meanwhile Humberto is just about Cat 2 at 85 knots, but the eyewall has been struggling to properly close, probably due to some dry air winding in from the southwest. It might just help Bermuda by limiting strengthening over the next few hours before shear increases.

    diag20190917T180109_amsr2_85.png

    Water vapour

    20190917.1800.goes15.x.wv1km.09LHUMBERTO.85kts-961mb-306N-739W.100pc.jpg


  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    For the past two days the forecast track has been extremely consistent in having Humberto's centre passing 70-80 NM from Bermuda at its closest point. Hasn't budged a bit. Intensity at that stage (1903Z) should be around 85 knots, with hurricane-force winds extending around 60 NM to the southeast of the centre. Might just keep Bermuda away from the worst of it.

    al092019.19091700.gif


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  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    TD Ten has been named TS Jerry, east of the Lesser Antilles. It shouldn't amount to much over the next few days, possibly touching hurricane status as it stays away from land.

    Humberto is now 105-kt Cat 3, with an expanded wind-field (64-kts now put to 90 NM from the centre. Not so good for Bermuda, which will feel hurricane conditions overnight tonight.


  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    The centre of Humberto passed almost right over buoy 41008 earlier, which has an anemometer height of 4 metres. Again note how much higher the 1-minute mean speed is than the 8-minute mean (in the wind/pressure graph). Note the difference between the 4-metre and calculated 10-metre speeds.

    sfcplot_09L_2019091818.png

    490977.png

    490978.png

    490979.png

    490980.png


  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Live webcam from Bermuda. Getting rough now...

    https://www.earthcam.com/world/bermuda/pembroke/?cam=bermuda


  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Live AWOS wind readings. 54 gust 70 kts now at Crescent. AvMet30 is an anemometer at 30 metres.

    http://weather.bm/tools/graphics.asp?name=ISLAND_AWOS&user=


  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    490992.png

    490993.png


  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Read the first line
    500 PM AST Wed Sep 18 2019

    Normal communications with the Bermuda Weather Service have been
    disrupted due to a lightning strike.


    Humberto is taking on more of a hybrid-extratropical structure based
    on most of the rain shield having been displaced to the left or
    poleward side of the circulation now as seen in Bermuda weather
    radar data, and also in conventional and passive microwave satellite
    imagery. Sustained hurricane-force winds and gusts have been
    measured by amateur radio operators across the island, with a peak
    gust to 104 mph having been reported thus far at Ports Island,
    Bermuda. The initial intensity of 105 kt on the previous advisory
    has been maintained since little overall change in the structure has
    occurred since the last aircraft reconnaissance mission 6 hours ago.

    The initial motion estimate is 060/17 kt. There are no significant
    changes to the previous forecast track or reasoning. Humberto has
    basically remained on track during the past 24 hours. The hurricane
    is expected to continue accelerating toward the east-northeast
    tonight and Thursday morning, with the center expected to pass
    about 80 nmi northwest of Bermuda early this evening. A turn toward
    the northeast and north-northeast is forecast to occur by early
    Thursday afternoon, followed by a motion toward the east-northeast
    by 48 hours, with the latter motion continuing through 96 hours. The
    new official track forecast is similar to the previous advisory
    track, and lies close to the tightly packed TVCN, NOAA-HCCA, and
    FSSE consensus track models.

    Humberto is now fully embedded within an anticyclonically curved
    right-rear jet entrance region. As a result, some fluctuations in
    strength could occur during the next 12 hours or so. Thereafter,
    strong southwesterly vertical wind shear in excess of 50 kt, along
    with cold upwelling beneath the hurricane, should combine to induce
    steady weakening. By 48 hours, the global models continue to
    forecast Humberto to merge with a frontal system, and the NHC
    intensity forecast calls for extratropical transition around that
    time. The official intensity forecast follows an average of the
    global models' intensity forecasts due to Humberto's hybrid nature,
    which is not being captured properly by the tropical-cyclone-based
    consensus intensity models.

    Key Messages:

    1. A prolonged period of dangerous winds is expected to continue on
    Bermuda through Thursday morning, with hurricane-force winds
    expected during the next several hours. Preparations to protect
    life and property should be rushed to completion.

    2. Storm surge and dangerous breaking waves could cause coastal
    flooding tonight and Thursday along the southern coast of Bermuda.

    3. Swells will continue to affect the northwestern Bahamas and the
    southeastern coast of the United States from east-central Florida to
    North Carolina during the next couple of days, creating life-
    threatening surf and rip current conditions.

    FORECAST POSITIONS AND MAX WINDS

    INIT 18/2100Z 33.0N 66.3W 105 KT 120 MPH
    12H 19/0600Z 34.6N 63.6W 105 KT 120 MPH
    24H 19/1800Z 37.4N 61.0W 95 KT 110 MPH
    36H 20/0600Z 39.8N 60.0W 75 KT 85 MPH
    48H 20/1800Z 41.6N 58.7W 60 KT 70 MPH...POST-TROP/EXTRATROP
    72H 21/1800Z 43.9N 47.0W 45 KT 50 MPH...POST-TROP/EXTRATROP
    96H 22/1800Z 49.0N 30.0W 45 KT 50 MPH...POST-TROP/EXTRATROP
    120H 23/1800Z...DISSIPATED/ABSORBED


  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    You don't see this often in a METAR, GP99KT (gust >99 kt). This was Humberto brushing past Bermuda last night. Other stations reported slightly higher winds.

    SPECI TXKF 190058Z 26044G64KT 6000 R12/0125N BLPY BKN015 OVC030 25/20 Q0991 RMK PRESRR=

    METAR TXKF 190055Z 25054G81KT 6000 R12/0100N BLPY BKN015 OVC030 25/20 Q0989 RMK PRESRR=

    SPECI TXKF 190012Z 26053G75KT 3600 R12/M0050D BLPY OVC020 23/21 Q0986=

    METAR TXKF 182355Z 27063G95KT 0800 R12/0900U -SHRA BLPY OVC010 23/22 Q0981=

    SPECI TXKF 182331Z 26070GP99KT 0550 R12/0600N -SHRA BLPY OVC009TCU 22/21 Q0980 RMK TCU ALQDS=

    SPECI TXKF 182328Z 26071G97KT 0900 R12/0800N -SHRA BLPY OVC009TCU 22/21 Q0980 RMK TCU ALQDS=

    SPECI TXKF 182319Z 24060G83KT 0900 R12/1200D -SHRA BLPY OVC009TCU 22/22 Q0980 RMK TCU ALQDS=

    SPECI TXKF 182309Z 23050G72KT 1000 R12/P2000N -SHRA BLPY OC009TCU 22/22 Q0982 RMK TU SW-N=

    SPECI TXKF 182302Z 22048G69KT 1000 R12/P2000N -SHRA BLPY OVC015TCU 22/22 Q0982 RMK TCU SW-W=

    METAR TXKF 182255Z 23058G75KT 1200 R12/P2000N -SHRA BLPY OVC015TCU 22/21 Q0982 RMK TCU DSNT SW=

    SPECI TXKF 182220Z 21048G71KT 1200 R12/P2000N BLPY VCSH OVC020 25/21 Q0984 RMK PRESFR=

    METAR COR TXKF 182155Z 21046G64KT 3200 BLPY BKN025 OVC037 27/21 Q0985 RMK PRESFR=

    SPECI TXKF 182142Z 20045G62KT 3200 BLPY BKN025 OVC37 27/21 Q0985=

    METAR TXKF 182055Z 20035G54KT 3600 BLPY BKN032 OVC065 28/22 Q0989=

    SPECI TXKF 182019Z 20037G56KT 3600 BLPY OVC030 28/23 Q0990=

    METAR TXKF 181955Z 19034G48KT 9999 VCSH BKN024 BKN042 OVC300 28/23 Q0991=


  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Looks like Bermuda could get hit again, this time by Jerry.

    al102019.19091912.gif


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  • Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Jerry is now a hurricane.

    Interesting comment in the latest NHC discussion regarding the importance of aircraft recon data in finteuning intensity estimates. This has been true of several storms of late (Michael, Patricia, etc.), which would probably not have been given such high intensities in the days before sophisticated aircraft recon. This is bound to have an effect when it comes to the long-term stats, with a false increasing trend relative decades ago, and the same could be said about satellite v pre-satellite era.
    1100 PM AST Thu Sep 19 2019

    The Air Force Hurricane Hunters investigating Jerry this evening found that the hurricane has strengthened. Based on the 700 mb flight-level winds from the aircraft, the current intensity is estimated to be about 90 kt. It should be noted that this is substantially higher than the intensity estimates provided from satellite data, and underscores the value of aerial reconnaissance of tropical cyclones. An expected increase in vertical shear in a day or so is expected to cause a weakening trend to commence in 12 to 24 hours, however, Jerry should remain a hurricane throughout the forecast period. This NHC intensity forecast is higher than the previous one mainly due to the higher initial wind speed, and is near or a little above the model consensus.


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