ATL: GONZALO - Post-Tropical - Discussion

[NDG]

Latest pass by the recon the pressure is down 1 mb to 942mb.

[TheAustinMan]

Saved image:

http://i20.photobucket.com/albums/b245/ndgarcia/Gonzalo8_zpsehvhduze.gif

Strange looking loop. What is that?

If you're talking about the red band that appears during the animation, that's an artifact of the blending of images. The MIMIC product (which produces the loop shown) takes microwave imagery of Hurricane Gonzalo from various satellites and attempts to "blend" them together in an attempt to simulate motion and fluidity. The gap was likely a result of the product attempting to blend in a microwave image that had a data gap, and after its brief appearance goes away as a new, updated microwave image that has complete data is blended over.

[NDG]

Saved image:

http://i20.photobucket.com/albums/b245/ ... vhduze.gif

Strange looking loop. What is that?

MIMIC (Morphed Integrated Microwave Imagery )

[gatorcane]

some westerly shear starting to impact Gonzalo, though still rather impressive tonight:

[Alyono]

dont think that's shear. Often, storms undergoing eyewall replacements look sheared, but they are not sheared

One thing this is doing though is accelerating. This will be flying by tomorrow morning

[EquusStorm]

Good lord. I do have to think the wind will be down even if the pressure is falling, due to increasing westerly shear finally about to impinge on the circulation...

[NDG]

Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 17th day of the month at 0:50Z
Agency: United States Air Force
Aircraft: Lockheed WC-130J Hercules with reg. number AF97-5305
Storm Number & Year: 08 in 2014
Storm Name: Gonzalo (flight in the North Atlantic basin)
Mission Number: 10
Observation Number: 15
A. Time of Center Fix: 17th day of the month at 0:33:30Z
B. Center Fix Coordinates: 27°34'N 67°49'W (27.5667N 67.8167W)
C. Minimum Height at Standard Level: 2,586m (8,484ft) at 700mb
D. Estimated (by SFMR or visually) Maximum Surface Wind: 102kts (~ 117.4mph)
E. Location of the Estimated Maximum Surface Wind: 15 nautical miles (17 statute miles) to the NE (47°) of center fix
F. Maximum Flight Level Wind Inbound: From 148° at 130kts (From the SSE at ~ 149.6mph)
G. Location of Maximum Flight Level Wind Inbound: 26 nautical miles (30 statute miles) to the ENE (59°) of center fix
H. Minimum Sea Level Pressure: 942mb (27.82 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 9°C (48°F) at a pressure alt. of 3,068m (10,066ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 16°C (61°F) at a pressure alt. of 3,040m (9,974ft)
K. Dewpoint Temp & Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Closed Wall
M. Eye Shape & Diameter: Circular with a diameter of 44 nautical miles (51 statute miles)
N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Level: 700mb
O. Navigational Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 1 nautical mile

Remarks Section - Remarks That Were Decoded...
Maximum Flight Level Wind: 136kts (~ 156.5mph) which was observed 40 nautical miles (46 statute miles) to the SSE (160°) from the flight level center at 22:58:30Z
Maximum Flight Level Temp: 17°C (63°F) which was observed 10 nautical miles (12 statute miles) to the SSW (210°) from the flight level center

Remarks Section - Additional Remarks...
STRONG EYEWALL W THRU N
ABOUT THIRD OF INNER EYEWALL REMAINS NW SIDE
CTR DROPSONDE SFC WIND 115 DEG 02 KTS

[ozonepete]

Saved image:

http://i20.photobucket.com/albums/b245/ndgarcia/Gonzalo8_zpsehvhduze.gif

Strange looking loop. What is that?

If you're talking about the red band that appears during the animation, that's an artifact of the blending of images. The MIMIC product (which produces the loop shown) takes microwave imagery of Hurricane Gonzalo from various satellites and attempts to "blend" them together in an attempt to simulate motion and fluidity. The gap was likely a result of the product attempting to blend in a microwave image that had a data gap, and after its brief appearance goes away as a new, updated microwave image that has complete data is blended over.

I don't think he was familiar with that loop at all - right ftolmsteen? Very few are. Anyway AustinMan did a great job of explaining it. It's basically a collection of 89 GHZ microwave satellite images that are put together into a movie. The 89 GHZ microwave images can "see" below obstructing high clouds and thus show us the core structure so we can follow the motion of the eye and also how multiple eye-walls form, collapse and reform in what we call ERCs or Eye-wall Replacement cycles. Go to the CIMSS site http://tropic.ssec.wisc.edu/ and then click on MIMIC-TC under the map and you can pick the loops for the cyclone you want to follow. It is very invaluable technology that we use a lot now.

[MGC]

Gonzalo has gone from a 2 mile wide eye to a 44 mile wide eye. I think it is going to be hard for hurricane force winds to miss Bermuda. Hope everyone on Bermuda stays safe.....MGC

[tolakram]

Looks like the larger eye is about to open again. Looks pretty darn large.

live loop: http://wwwghcc.msfc.nasa.gov/cgi-bin/get-goes?satellite=GOES-E%20CONUS&lat=28&lon=-67&info=ir&zoom=1&width=1200&height=720&quality=95&type=Animation&palette=ir3.pal&numframes=15&mapcolor=yellow

[ozonepete]

Looks actually like an ERC has just completed - that's why we have a larger eye. And that larger eye-wall should be quite stable and not open up at all but rather start contracting again just like it's done a couple of times already. The only thing that can stop a new ERC is dry air intrusion or shear.

[ozonepete]

Let's not forget that such a large eye is quite stable and that could help this possibly go annular. Look at Isabel from 2003. It went annular at either cat 4 or cat 5 (forgot which). But annular is very stable and makes weakening much less likely.

[JahJa]

I will have a webcam at the following address if anyone wants to see it. Not much to see at the moment but I will re-adjust in the day time if I need to.

bda.click2stream.com

[ozonepete]

I will have a webcam at the following address if anyone wants to see it. Not much to see at the moment but I will re-adjust in the day time if I need to.

bda.click2stream.com

Sure we want it. Thanks! And good luck with this very serious threat.

[ozonepete]

Still assessed at 120 knots and things still look very dangerous for Bermuda. Hope everyone there is done with their preps. Here's the latest 11PM NHC discussion:

HURRICANE GONZALO DISCUSSION NUMBER 19
NWS NATIONAL HURRICANE CENTER MIAMI FL AL082014
1100 PM AST THU OCT 16 2014

The latest hurricane hunter mission into Gonzalo found peak flight-level winds of 136 kt, with SFMR values of 107 kt. A blend of these winds gives a surface wind speed estimate of about 120 kt for the current intensity, a bit lower than before. This slight weakening is also suggested by the latest satellite pictures, which show that the eye has become less distinct.

No significant change in strength is forecast for the next 12 hours while Gonzalo remains over warm water with little shear, although some fluctuations are possible due to internal eyewall cycle dynamics. A more steady weakening is expected by late tomorrow since the hurricane will be moving over substantially cooler SSTs. However, any weakening is probably too late to spare Bermuda, with almost all of the guidance showing the system as a major hurricane as it moves nearby. In 36-48 hours, shear is forecast to increase dramatically which should continue the weakening process, and start extratropical transition over cold waters. The NHC forecast is about the same as the previous interpolated forecast, and follows the trend of the intensity consensus. Extratropical transition is still shown at day 3, although it could be close to losing tropical characteristics just after 48 hours.

Gonzalo is accelerating toward the north-northeast, now moving at about 12 kt. Global models are in good agreement on the hurricane entering the flow ahead of a deep-layer trough over the eastern United States, and this pattern is expected to cause Gonzalo to accelerate further toward the north-northeast during the next 48
hours. All of the reliable guidance show Gonzalo passing over or within 30 nm to the west of the island, and little change has been made to the forecast track through 2 days. Gonzalo should race northeastward and east-northeastward as an extratropical cyclone over the far north Atlantic.

Significant coastal flooding on Bermuda is likely if Gonzalo continues on the current NHC forecast track. Although specific amounts cannot be forecast for Gonzalo, Hurricane Fabian produced an estimated 10 feet of storm surge when it moved over Bermuda as a major hurricane in 2003, and similar values could occur with Gonzalo.



FORECAST POSITIONS AND MAX WINDS

INIT 17/0300Z 28.0N 67.5W 120 KT 140 MPH
12H 17/1200Z 29.7N 66.5W 115 KT 130 MPH
24H 18/0000Z 32.5N 64.9W 105 KT 120 MPH
36H 18/1200Z 36.4N 62.5W 95 KT 110 MPH
48H 19/0000Z 42.0N 57.9W 85 KT 100 MPH
72H 20/0000Z 52.0N 39.0W 55 KT 65 MPH...POST-TROP/EXTRATROP
96H 21/0000Z 56.5N 12.0W 35 KT 40 MPH...POST-TROP/EXTRATROP
120H 22/0000Z...DISSIPATED

[TheStormExpert]

Looks like this is the first real serious threat for Bermuda since Fabian of 2003, hopefully Bermuda and everyone on that island fair well and it goes through without any series issues, but sadly that seems probably unlikely at this point.

[TheStormExpert]

I realize I have mentioned this probably before, but out of curiosity does anyone know if The Weather Channel sent anyone to cover Gonzalo in Bermuda?

[ozonepete]

I realize I have mentioned this probably before, but out of curiosity does anyone know if The Weather Channel sent anyone to cover Gonzalo in Bermuda?

I haven't heard anything yet but I would bet my credentials that Cantore will be there unless he has some dire emergency. He always goes to the big ones. Always.

[ozonepete]

Wow just look at the satellite loops. It's clearly starting another Eye-wall Replacement. This TC just loves ERCs.

[TheStormExpert]

Wow just look at the satellite loops. It's clearly starting another Eye-wall Replacement. This TC just loves ERCs.

Why do these Eyewall Replacement Cycles keep occurring? This like the third or fourth one.