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hlcater

Major Hurricane Delta

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I dont know if a strike to Cancun or Cozumel weakens it much. That area is completely flat and it will have a quick forward speed at that point spending probably less than 6 hours over land. 

There's a cold pool of water just north of Cancun year-round mostly do to micro-climate trades there. It only extends north 50-100 miles. That and some land interaction would halt intensification. It might regain major intensity in the central GOM for a time. Again, this is hypothetical IF it crossed the NE Yucatán. But really the best chance for Cat 4/5 is going to be if Delta undergoes RI through Wednesday prior to traversing land or in the channel.
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984 mb, wow!  I was not expecting that.  Frankly, the core convection is a bit meager.  The color IR presentation isn't great.  However, the visible loop shows it has nice organization.  It could take off tonight if it can fire more widespread deep convection over/around the center.

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5 minutes ago, hawkeye_wx said:

984 mb, wow!  I was not expecting that.  Frankly, the core convection is a bit meager.  The color IR presentation isn't great.  However, the visible loop shows it has nice organization.  It could take off tonight if it can fire more widespread deep convection over/around the center.

Give me a good vis with weak IR to a big dark blob with 9 competing potential LLC’s

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Recon is heading N now but I am uncertain if they're actually finished with the mission or are going to try for another pass.

 

Edit: Well they've dropped back down to operational altitude so I guess they figured out the issue and are resuming reconnaissance.

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NHC now forecasting a major hurricane to impact Yucatán peninsula, including Cancun. Yikes. Anyone happen to know what the oceanic shelf is like there (how surge prone it is)?

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Brown typed a novel. Forecasting a major hurricane now. Track also shifted west towards NE Yucatán.

000
WTNT41 KNHC 052055
TCDAT1

Tropical Storm Delta Discussion Number   5
NWS National Hurricane Center Miami FL       AL262020
500 PM EDT Mon Oct 05 2020

Visible satellite imagery shows that the convective banding of Delta 
has continued to quickly improve since this morning. The primary 
convective band now wraps entirely around the center, with what 
appears to be a banding-type eye feature occasionally noted.  There 
are some dry slots between the convective bands but those appear to 
be gradually filling in.  A NOAA Hurricane Hunter aircraft currently 
collecting data in the storm environment found peak SFMR winds of 55 
kt during its first pass through the center from northwest to 
southeast.  The plane also reported a minimum pressure of 983 mb, 
much lower than previously estimated.  The aircraft also observed an 
18 nmi-wide-eye that was open to the west-northwest.   Assuming that 
there are stronger winds yet to be sampled in the northeastern 
quadrant, the initial intensity has been raised to 60 kt. 

Delta is situated within a very conducive environment for
strengthening.  The storm will be moving over SSTs of 29-30 degrees
Celsius and the vertical wind shear is forecast to remain 5 kt or
less while Delta traverses the northwestern Caribbean. These
conditions are expected to allow for rapid strengthening over the
next 24 to 36 hours.  The SHIPS Rapid Intensification Index gives a
better than 50 percent chance of a 35-40 kt increase in wind speed
over the next 24 hours.  The NHC intensity forecast follow suit by
calling for rapid intensification over the next day or so, and 
Delta is forecast to be a major hurricane when is passes near or 
over the northeastern portion of the Yucatan peninsula.  Once 
the storm reaches the central Gulf of Mexico in 60-72 hours, 
increasing southwestern vertical wind shear and cooler shelf waters 
over the northern Gulf are likely to result in some reduction in 
wind speed as the system nears the northern Gulf coast.  Although 
there is still significant uncertainty regarding Delta's intensity 
when it nears the northern Gulf coast, it is becoming increasing 
likely that the system will pose a significant wind and storm surge
threat to a portion of that area.

The center has jogged southward again this afternoon, which appears 
to be primarily due to the system organizing rather than a true 
storm motion.  The initial motion estimate remains an uncertain 
275/7 kt. Delta should begin moving west-northwestward this evening, 
and a west-northwestward to northwestward motion around the 
southwestern portion of a deep-layer ridge to its northeast is 
expected over the next couple of days. The more southward initial 
position and more ridging over the eastern Gulf of Mexico has 
resulted in a significant westward shift in the track envelope 
through the first 60-72 hours.  The NHC has been adjusted in that 
direction, and this has required the issuance of a Hurricane Warning 
for the northeastern portion of the Yucatan peninsula of Mexico.   
After 72 hours, a mid- to upper-level trough is forecast to develop 
over Texas which should cause Delta to turn northward and then 
north-northeastward toward the northern Gulf Coast.  Although the 
track forecast has not changed much during the latter portion of the 
period, there is more cross-track spread in the model guidance than 
before, which has increased the uncertainty regarding potential 
landfall and the timing of Delta's approach to the northern Gulf 
Coast.

Key Messages:

1. Dangerous storm surge and hurricane conditions are expected 
within portions of the northern Yucatan Peninsula of Mexico and are 
possible in extreme western Cuba beginning Tuesday night, and a 
Hurricane Warning is in effect.

2. Heavy rainfall will affect portions of Jamaica, the Cayman 
Islands, western Cuba and the northern Yucatan Peninsula during the 
next few days. This rainfall could lead to significant flash 
flooding and mudslides.  

3. Tropical storm conditions are expected in portions of the Cayman 
Islands beginning tonight or early Tuesday, and a Tropical Storm 
Warning is in effect.  

4. Delta is forecast to approach the northern Gulf Coast late this 
week as a hurricane. While there is large uncertainty in the track 
and intensity forecasts, there is an increasing risk of dangerous 
storm surge, wind, and rainfall hazards along the coast from 
Louisiana to the western Florida Panhandle beginning Thursday night 
or Friday. Residents in these areas should ensure they have their 
hurricane plan in place and monitor updates to the forecast of 
Delta.

FORECAST POSITIONS AND MAX WINDS

INIT  05/2100Z 16.2N  79.4W   60 KT  70 MPH
 12H  06/0600Z 17.1N  80.9W   75 KT  85 MPH
 24H  06/1800Z 19.0N  83.5W   95 KT 110 MPH
 36H  07/0600Z 21.0N  86.2W  105 KT 120 MPH
 48H  07/1800Z 22.6N  88.7W  105 KT 120 MPH
 60H  08/0600Z 23.7N  90.6W  105 KT 120 MPH
 72H  08/1800Z 24.8N  91.5W   95 KT 110 MPH
 96H  09/1800Z 28.5N  91.5W   85 KT 100 MPH
120H  10/1800Z 33.0N  89.0W   40 KT  45 MPH...INLAND

$$
Forecaster Brown

 

205518_5day_cone_no_line_and_wind.png

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NHC now forecasting a major hurricane to impact Yucatán peninsula, including Cancun. Yikes. Anyone happen to know what the oceanic shelf is like there (how surge prone it is)?

Cozumel had a 15.4 foot surge during Wilma and an 18.6 foot surge was recorded along the NE Yucatán coast during Gilbert for comparison. They can get a high surge in that region with a large hurricane.56557f9ccd8804dfe8efa38ca04159e9.jpg&key=dffced20469c7a1326d541b473890fdfe47ba164888158b43f3d7815e0cc248a

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978mb this pass. 65kt sfmr, but it's flagged.

Edit: Extrap was lower but drop was 984mb again.

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A massive convective burst in the eastern eyewall is rapidly expanding.  It looks like it's going to dwarf the last few. This might be the breaking point.   

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25 minutes ago, Amped said:

A massive convective burst in the eastern eyewall is rapidly expanding.  It looks like it's going to dwarf the last few. This might be the breaking point.   

All of a sudden, it appears to rapidly be developing a core.

 

 

 

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Well here we are here in the Florida west peninsula, escaping them all season, why LA again?!

If I were the Earth, it's not the drinking and partying in New Orleans, it's not the sparsely populated the areas west of NE irritating me, so what?

The oil digging in the Gulf pricking my skin?

OK, time for a Delta Banter thread?

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Product: NOAA Vortex Message (URNT12 KWBC)
Transmitted: 5th day of the month at 23:17Z
Agency: National Oceanic and Atmospheric Administration (NOAA)
Aircraft: Lockheed WP-3D Orion (Reg. Num. N43RF)
Storm Number & Year: 26 in 2020
Storm Name: Delta (flight in the North Atlantic basin)
Mission Number: 1
Observation Number: 24

A. Time of Center Fix: 5th day of the month at 22:53:41Z
B. Center Fix Coordinates: 16.41N 79.50W
B. Center Fix Location: 210 statute miles (337 km) to the WSW (238°) from Kingston, Jamaica.
C. Minimum Height at Standard Level: 2,950m (9,678ft) at 700mb
D. Minimum Sea Level Pressure: 981mb (28.97 inHg)
E. Dropsonde Surface Wind at Center: From 130° at 15kts (From the SE at 17mph)
F. Eye Character: Closed
G. Eye Shape: Elliptical (oval shaped)
G. Orientation of Major Axis in Elliptical Eye: 90° to 270° (E to W)
G. Length of Major Axis in Elliptical Eye: 17 nautical miles (20 statute miles)
G. Length of Minor Axis in Elliptical Eye: 11 nautical miles (13 statute miles)
H. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 58kts (66.7mph)
I. Location & Time of the Estimated Maximum Surface Wind Inbound: 6 nautical miles to the SSE (161°) of center fix at 22:52:13Z
J. Maximum Flight Level Wind Inbound: From 253° at 59kts (From the WSW at 67.9mph)
K. Location & Time of the Maximum Flight Level Wind Inbound: 8 nautical miles to the SSE (159°) of center fix at 22:51:43Z
L. Estimated (by SFMR or visually) Maximum Surface Wind Outbound: 61kts (70.2mph)
M. Location & Time of the Estimated Maximum Surface Wind Outbound: 9 nautical miles to the NW (320°) of center fix at 22:57:38Z
N. Maximum Flight Level Wind Outbound: From 55° at 68kts (From the NE at 78.3mph)
O. Location & Time of the Maximum Flight Level Wind Outbound: 11 nautical miles (13 statute miles) to the NW (319°) of center fix at 22:58:09Z
P. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 11°C (52°F) at a pressure alt. of 3,062m (10,046ft)
Q. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 17°C (63°F) at a pressure alt. of 3,053m (10,016ft)
R. Dewpoint Temp & Sea Surface Temp: Not Available
S. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
S. Fix Level: 700mb
T. Navigational Fix Accuracy: 0.01 nautical miles
T. Meteorological Accuracy: 0.5 nautical miles

Remarks Section:

Maximum Flight Level Wind: 68kts (~ 78.3mph) which was observed 11 nautical miles (13 statute miles) to the NW (319°) from the flight level center at 22:58:09Z

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HWRF with a high end Cat 3/Cat 4 landfall on Cancún and that may be underdone given current satellite presentation and ideal conditions for the next 36 hours.

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The resort city of Cancun has a population of 743,000.  If this does become category five back out over the gulf I would think eyewall replacement cycles along with shear would be the best hope of any possible weakening as it approaches northern gulf coast.  Even if it goes back to a three, Katrina did have category 5 surge due to its intensity over the gulf as has been mentioned.  This looks to be a monster in the making wherever it travels.

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Does anyone remember the last time we had a tropical cyclone, at a similar stage as Delta, entering the nw Caribbean with a couple days of prime strengthening ahead of it?  It really doesn't happen often.  Usually, systems are just organizing in that area.

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Delta was classified a tropical depression at 11 PM EDT last night and upgraded to a 40 MPH tropical storm at 8 AM EDT this morning. That we are at hurricane intensity in less than 24 hours with a closed eyewall is pretty ominous. It's quite possible that Delta was already a TS prior to TD classification last night, regardless, this is signifantly fast cyclogenesis hurricane. It looks like Delta is likely going to shame the initial intensity guidance from the past few days as well. Also, it's one thing for the ECMWF to missed TCG (yet again) on a system that remains weak or even low-end hurricane. But this is really just very poor global modeling right now seeing as how we're about to watch a intense major hurricane unfold in a climatologically favored region and timescale. Not even any of its ensembles had a major. #2020things

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