Kermit.de.frog Registered User
#1

Now a Category 1 hurricane approaching the Gulf of Mexico

Latest guidance

Key Messages:

1. Michael is forecast to be a dangerous major hurricane when it
reaches the northeastern Gulf Coast on Wednesday, and life-
threatening storm surge is possible along portions of the Florida
Gulf Coast regardless of the storm's exact track or intensity.
Residents in the storm surge and hurricane watch areas should follow
any advice given by local officials, as storm surge and hurricane
warnings will likely be issued later today.

2. Heavy rainfall from Michael could produce life-threatening flash
flooding from the Florida Panhandle and Big Bend region into
portions of the Carolinas through Thursday.

3. Hurricane conditions will spread over portions of western Cuba
this afternoon, where a hurricane warning is now in effect.
Tropical storm conditions are expected over the northeastern Yucatan
Peninsula and the Isle of Youth today.

4. Michael is expected to produce heavy rainfall and flash flooding
over portions of western Cuba and the northeastern Yucatan Peninsula
of Mexico during the next couple of days.

FORECAST POSITIONS AND MAX WINDS

INIT 08/1500Z 21.2N 84.9W 65 KT 75 MPH
12H 09/0000Z 22.6N 85.3W 85 KT 100 MPH
24H 09/1200Z 24.4N 85.9W 95 KT 110 MPH
36H 10/0000Z 26.4N 86.4W 105 KT 120 MPH
48H 10/1200Z 28.6N 86.1W 105 KT 120 MPH

72H 11/1200Z 33.0N 82.5W 45 KT 50 MPH...INLAND
96H 12/1200Z 37.8N 73.6W 50 KT 60 MPH...POST-TROP/EXTRATROP
120H 13/1200Z 42.8N 59.0W 55 KT 65 MPH...POST-TROP/EXTRATROP


Expect this to be literally a fast moving situation.

Expected to become a major Category 3 (conceivably higher depending on the rate of intensification and prime conditions in the Gulf) hurricane in the next 24 - 36 hours.







Infra red

https://www.tropicaltidbits.com/sat/satlooper.php?region=14L&product=ir

Aircraft Recon

https://www.tropicaltidbits.com/recon/

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sdanseo Registered User
#2

Not impossible for this to get to Cat 5. 18hrs ago NHC were predicting max 85kt. SSTs are very warm in the gulf and Caribbean.

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17-pdr Registered User
#3

Latest SHIPS forecast indicating 81 kts nearing landfall sometime Wednesday evening.

ftp://ftp.nhc.noaa.gov/atcf/stext/18100818AL1418_ships.txt

dfx- Moderator
#4

Wind shear was supposed to be the saviour?

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Gaoth Laidir Registered User
#5

It won't make CAT 3. I'd say the SHIPS has it bang on at around 80-85 kts max. It will completely miss the pool of highest ocean heat content in the middle of the Gulf, so another 15-20 knots or so as it leaves the warmest waters around Cuba will probably be the highest it will get. But it will be interesting to see if the NHC overstate it again. They've gone for the very top of the intensity guidance envelope. They've also analysed it at 70 knots at 18Z despite max SFMR winds of 54 kts around then.

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17-pdr Registered User
#6

dfx- said:
Wind shear was supposed to be the saviour?



Could yet be. 13-16 kts of shear up to landfall.


TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 70 75 77 79 80 80 81 77 74 68 67 57 38
V (KT) LAND 70 75 77 79 80 80 81 46 33 29 30 21 DIS
V (KT) LGEM 70 75 79 80 80 81 82 46 33 29 35 35 29
SHEAR (KT) 15 16 22 16 13 16 16 18 17 31 49 71 69

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Sleety_Rain Registered User
#7

Gaoth Laidir said:
It won't make CAT 3. I'd say the SHIPS has it bang on at around 80-85 kts max. It will completely miss the pool of highest ocean heat content in the middle of the Gulf, so another 15-20 knots or so as it leaves the warmest waters around Cuba will probably be the highest it will get. But it will be interesting to see if the NHC overstate it again. They've gone for the very top of the intensity guidance envelope. They've also analysed it at 70 knots at 18Z despite max SFMR winds of 54 kts around then.



EC has it @ 947hPa and near 140knots close to landfall

Gaoth Laidir Registered User
#8

Sleety_Rain said:
EC has it @ 947hPa and near 140knots close to landfall


140 knots? You mean kph. 165 kph sustained on this

https://weather.us/model-charts/euro/florida/wind-streamlines/20181010-2100z.html

Sleety_Rain Registered User
#9
Gaoth Laidir Registered User
#10

Sleety_Rain said:
The intensity is done on gusts no?


No, sustained winds. The NHC use 1-minute mean sustained, which is usually around 10% higher than the standard 10-minute mean.

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Sleety_Rain Registered User
#11

Gaoth Laidir said:
No, sustained winds. The NHC use 1-minute mean sustained, which is usually around 10% higher than the standard 10-minute mean.


I see that now- had forgotten briefly- although going on experience they seem to go with intensity near the maximum flight level winds they sample.

I'd love to see verification against the recorded sustained winds versus the forecast sustained winds versus the recorded gusts!

I would think that the recorded max gust is nearer the the forecast sustained wind or less

Gaoth Laidir Registered User
#12

Sleety_Rain said:
I see that now- had forgotten briefly- although going on experience they seem to go with intensity near the maximum flight level winds they sample.

I'd love to see verification against the recorded sustained winds versus the forecast sustained winds versus the recorded gusts!

I would think that the recorded max gust is nearer the the forecast sustained wind or less


They have a reduction factor for calculating surface winds from flight level winds, which is usually around 15-20%.

In my experience the reported speeds are nearly always less than forecast, especially for US-landfalls. The 1-minute sustained winds quoted by the NHC will be closer to the gusts as they are averaged over only 1 minute, in which time one decent gust will up the value. Remember that they're always the MAXIMUM sustained values, so there will also be other periods much lower than that too. That's why from an academic point of view the 10-minute speeds are more relevant, but for talking of potential damage the 1-minute are used.

Gaoth Laidir Registered User
#13

Scan at 2136Z shows the deep convection has pretty much formed an eye.

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M.T. Cranium Registered User
#14

Storm surge is probably the biggest concern given the flat nature of the Florida panhandle coastline and the timing (new moon is just occurring now). I do think it has some potential to strengthen to a major hurricane even though it misses that warmest pool of Gulf water, as it has done quite well organizing in a less than perfect situation between Yucatan and Cuba. Ocean buoy 42003 will be right in its path around 18z today.

https://www.ndbc.noaa.gov/station_page.php?station=42003

This link includes frequent updates and (during local daylight hours) pictures of the waves and sky conditions. Could get interesting by 15z. Current wind speeds around 30 to 50 knots. This buoy could be in the forward eyewall at some point.

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Gaoth Laidir Registered User
#15

Michael is now leaving the area of very high ocean heat content that allowed it to intensify yesterday and will cross a very shallow pool over the next 12-24 hours. After that it remains away from the warmest waters.

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