ATL: HANNA - Remnants - Discussion

[HurricaneEdouard]

Winds aren't mixing down ideally, not sure why. Maybe due to the eyewall being incomplete

Happens a lot in rapidly intensifying TCs. The surface winds will probably catch up in a few hours.

[ronjon]

The dry air on the NW side seems to be mixing out. Look for more convection to fill in for a more symmetrical storm later on tonight. Once that happens, could see some more significant strengthening. May be a hurricane by early tomorrow am. If conditions continue this favorable a 100 mph cane is not out of the question at landfall.

[wx98]

Much weaker on the SW side, as expected.

[Hammy]

Winds aren't mixing down ideally, not sure why. Maybe due to the eyewall being incomplete

Happens a lot in rapidly intensifying TCs. The surface winds will probably catch up in a few hours.

Is that why sometimes intensification will appear to stall followed by a sudden jump in winds?

[Aric Dunn]

[sphelps8681]

My local met said it will be a hurricane be landfall.

[eastcoastFL]

Some decent bands hitting the coast now but this lady still has some time over water. Are we wobble watching yet? What does this angle of approach do as far as surge goes?

[eastcoastFL]

My local met said it will be a hurricane be landfall.

Nhc is calling for a CAT 1 at landfall.

[HurricaneEnzo]

Seems like the shape of the coastline gave Hanna the extra help she needed to really start wrapping up

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[NDG]

Josh will not regret deciding to go chase Hannah.

 https://twitter.com/iCyclone/status/1286839730382999563

[shiny-pebble]

Genuine question, is there some shear effecting it??? Or is it just tightening up?? Looks like some of the convection in the NW is being disrupted

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[ronjon]

Latest color IR:

https://www.tropicaltidbits.com/sat/satlooper.php?region=08L&product=ir

[HurricaneEdouard]

Winds aren't mixing down ideally, not sure why. Maybe due to the eyewall being incomplete

Happens a lot in rapidly intensifying TCs. The surface winds will probably catch up in a few hours.

Is that why sometimes intensification will appear to stall followed by a sudden jump in winds?

Yup; premiere example would be recon obs from Wilma during explosive deepening, 901mb pressure, 162 knot winds at 5,000 feet supporting no more than 130 knots at surface. Winds caught up within two or three hours.

In my experience, in rapidly intensifying TCs, FL winds always lag behind pressure and surface winds always lag behind FL winds.

[Highteeld]

993/6 knots per center dropsonde

[Highteeld]

Happens a lot in rapidly intensifying TCs. The surface winds will probably catch up in a few hours.

Is that why sometimes intensification will appear to stall followed by a sudden jump in winds?

Yup; premiere example would be recon obs from Wilma during explosive deepening, 901mb pressure, 162 knot winds at 5,000 feet supporting no more than 130 knots at surface. Winds caught up within two or three hours.

I wish i had a comprehensive understanding of why this happens. I've seen it before but don't understand the meteorology behind the lag in sfc winds.

[Do_For_Love]

Genuine question, is there some shear effecting it??? Or is it just tightening up?? Looks like some of the convection in the NW is being disrupted

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I think the issue is with dry air from the continental US iirc, Hanna has been struggling a bit in her NW quadrant all day. Good thing too!

[HurricaneEdouard]

993/6 knots per center dropsonde

Pretty much cements 992mb for MSLP, then.

[Aric Dunn]

993/6 knots per center dropsonde

Pretty much cements 992mb for MSLP, then.

next pass probably 990..

[HurricaneAndre2008]

Product: NOAA Vortex Message (URNT12 KWBC)
Transmitted: 25th day of the month at 1:57Z
Agency: National Oceanic and Atmospheric Administration (NOAA)
Aircraft: Lockheed WP-3D Orion (Reg. Num. N43RF)
Storm Number & Year: 08 in 2020
Storm Name: Hanna (flight in the North Atlantic basin)
Mission Number: 5
Observation Number: 11

A. Time of Center Fix: 25th day of the month at 1:33:22Z
B. Center Fix Coordinates: 27.05N 94.53W
B. Center Fix Location: 155 statute miles (250 km) to the S (173°) from Galveston, TX, USA.
C. Minimum Height at Standard Level: 1,367m (4,485ft) at 850mb
D. Minimum Sea Level Pressure: 993mb (29.33 inHg)
E. Dropsonde Surface Wind at Center: From 105° at 6kts (From the ESE at 7mph)
F. Eye Character: Open in the west
G. Eye Shape & Diameter: Circular with a diameter of 22 nautical miles (25 statute miles)
H. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 52kts (59.8mph)
I. Location & Time of the Estimated Maximum Surface Wind Inbound: 22 nautical miles (25 statute miles) to the NE (35°) of center fix at 1:27:29Z
J. Maximum Flight Level Wind Inbound: From 127° at 72kts (From the SE at 82.9mph)
K. Location & Time of the Maximum Flight Level Wind Inbound: 35 nautical miles (40 statute miles) to the NNE/NE (34°) of center fix at 1:23:55Z
L. Estimated (by SFMR or visually) Maximum Surface Wind Outbound: 32kts (36.8mph)
M. Location & Time of the Estimated Maximum Surface Wind Outbound: 24 nautical miles (28 statute miles) to the SW (226°) of center fix at 1:40:01Z
N. Maximum Flight Level Wind Outbound: From 326° at 35kts (From between the NW and NNW at 40.3mph)
O. Location & Time of the Maximum Flight Level Wind Outbound: 28 nautical miles (32 statute miles) to the SW (227°) of center fix at 1:40:56Z
P. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 19°C (66°F) at a pressure alt. of 1,551m (5,089ft)
Q. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 21°C (70°F) at a pressure alt. of 1,539m (5,049ft)
R. Dewpoint Temp (collected at same location as temp inside eye): 19°C (66°F)
R. Sea Surface Temp (collected at same location as temp inside eye): Not Available
S. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
S. Fix Level: 850mb
T. Navigational Fix Accuracy: 0.01 nautical miles
T. Meteorological Accuracy: 1 nautical mile

Remarks Section:

Maximum Flight Level Wind: 72kts (~ 82.9mph) which was observed 35 nautical miles (40 statute miles) to the NNE/NE (34°) from the flight level center at 1:23:55Z
General Note About Vortex Messages:
- Reported winds are usually averaged over a 10 second period. (The National Hurricane Center's advisory wind speeds are the highest expected winds averaged over a 1 minute period.)

[shiny-pebble]

Really looks like its trying to close off that core before dry air gets in

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