Comparisons anyone?.......

[dixiebreeze]

Between the days of August 17th and 20th, the tropical storm passed south of the center of a high pressure over the eastern Atlantic. Steering currents carried Andrew closer to a strong upper-level low pressure system centered about 500 nautical miles to the east-southeast of Bermuda. The currents also carried Andrew to a trough that extended southward from Andrew for a few hundred miles. These currents slowly but surely changed and Andrew decreased in speed on a course which became northwesterly. With the luck of this change in heading, Andrew spared the Lesser Antilles. The change in track also brought the tropical storm directly into a place of strong southwesterly vertical wind shear and quite high surface pressures to its north. At this time, the maximum wind speed of Andrew varied little. However, right after this time a rather remarkable evolution occurred. Satellite shots show that Andrew produced deep convection only sporadically for several days, mainly in several bursts of about 12 hours duration. Finally, the very deep convection did not persist very long at all. Instead, Andrew had the low-level circulation taken away from him by the strong southwesterly flow in upper levels of the atmosphere. Reconnaissance aircrafts took a flight into Andrew and on the 20th day of August, found that the cyclone had dissipated enough to be a low-level circulation center. His central pressure rose considerably. However, the flight data indicated that Andrew kept a very vigorous circulation aloft. Andrew was estimated on 20th of August to have been a tropical storm with 40 kt maximum sustained winds and an had a very astonishingly high central pressure of 1015 millibars. Tropical Storm Andrew headed towards the northwest for five days with little strengthening.


Very significant changes in environment near Andrew began on the 20 day of August. Satellite pictures in the water vapor channel indicated that the low aloft to the east-southeast of Bermuda weakened and split. The brunt of the low pressure opened into a trough which retreated towards the north direction. That evolution minimized the wind shear over Hurricane Andrew. The rest of the low pressure dropped southward to a position just southwest of Hurricane Andrew. This is where his circulation deepened the upper-level outflow over the tropical cyclone. At the same time, a strong dome of high pressure formed near the southeast coast of the United States. A ridge was built eastward from the high into the southwestern Atlantic with its axis lying just a little bit to the north of Andrew. The steering flow over the tropical storm became much more easterly. Andrew turned toward the west and accelerated to about 16 kt. These changes quickly intensified Hurricane Andrew.


Andrew reached hurricane strength in the early morning hours of August 22nd as a minimal hurricane with winds of 75 mph. Andrew was the first Atlantic hurricane to form from a tropical wave in nearly two years. An eye began to form that morning, and the rate of Andrew 's strengthening increased. Hurricane Andrew weakened when it passed over the western part of the Great Bahamas Bank, and his pressure rose to 941 mb. However, the hurricane rapidly reintensified during the last few hours before making landfall again when it moved over the Straits of Florida. In the morning of the 22nd, winds were at 75 mph, but by evening, winds were up to 110 mph, and by noon it had winds of 135 mph. Andrew quickly exploded from a tropical storm to a category 4 major hurricane in only 30 hours. By noon on the 23rd, Andrew was at its peak intensity with winds of 150 mph. By now, it was moving close to due west at 15 mph on a course that would carry it right through the Bahamas and Florida. Warnings were then posted, and they prepared for a twenty-three foot storm surge on the Bahamian shores. Around this time, residents along the entire Florida coast had their eyes studying the path of Andrew. Grocery stores overflowed with customers and residents stockpiled for necessities. As Andrew came closer, the forecasters' work continued around the clock. However, as the hours rolled by, they realized that they were situated at ground zero. Across South Florida, the word was out that Andrew was coming and with very scary strength.

[KeyLargoDave]

Reading anything about that storm raises my arm hair. The way it struggled and came back and that High just aimed it right at us and fired.

Comparisons are always tricky, each storm is a new batch of brownies, but thanks very much for the informative post.

[Tampa Bay Hurricane]

This is one of the big reasons I've kept a close eye on Irene. The possibilities are there, plus DT also mentioned a shot at major status (but not Andrew intensity).

[tallywx]

This NHC advisory discussion from Andrew always gives me chills, knowing what happened immediately after. I bolded some words and phrases for emphasis:

TROPICAL STORM ANDREW DISCUSSION NUMBER 15
NATIONAL WEATHER SERVICE MIAMI FL
11 AM EDT THU AUG 20 1992

SO FAR THIS MORNING... AIR FORCE RECONNAISSANCE REPORTS INDICATE A BROAD... POORLY ORGANIZED CENTER WITH THE LOWEST CENTRAL PRESSURE NEAR 1015 MB AND MAXIMUM SUSTAINED WINDS AT 1500 FEET OF 54 KNOTS.
NEARBY ENVIRONMENTAL PRESSURES OF 1020 MB APPARENTLY ARE SUFFICIENT TO SUSTAIN THOSE WINDS. SATELLITE PICTURES ARE STILL IMPRESSIVE FOR A SYSTEM THAT HAS GONE THROUGH SUCH A STRUGGLE.

ACCORDING TO WATER VAPOR IMAGERY... THE STRUGGLE MAY BE ENDING SOON AS THE LOW NORTHEAST OF ANDREW MOVES NORTHEASTWARD... AND THE TRAILING TROUGH COLLAPSES. HOWEVER... THERE IS SOME QUESTION CONCERNING THE INFLUENCE OF THE TROUGH NEAR PUERTO RICO. IF IT CLOSES OFF... THIS COULD IMPART A WESTWARD MOTION TO ANDREW.

THE OFFICIAL TRACK FORECAST ESSENTIALLY FOLLOWS THAT IN THE PREVIOUS ADVISORY AND REPRESENTS A BLEND OF MORE DIVERGENT MODEL PREDICTIONS. THE BAM RUNS AND QLM INDICATE A MORE WESTERLY TRACK...WHEREAS NHC90
CONTINUES A NORTHWEST TRACK. A MODEL CALLED VICBAR TURNS THE SYSTEM MORE NORTHWARD AND THE PRINCETON GFDL MODEL 36 HOURS AGO SHOWS POSITIONS CLOSE TO OUR TRACK.

THE INTENSITY SCENARIO REMAINS THE SAME. SOME STRENGTHENING IS POSSIBLE IF ANDREW SURVIVES THROUGH THE DAY.

[KeyLargoDave]

And three days later half of South Florida was running for the hills, with less than 24 hours to a Cat 5 landfall.

[Hurricaneman]

Andrew suprised alot of people

[Sanibel]

Like Charley, these small compact systems can be really boosted by August conditions...

[wxwatcher91]

I posted this earlier in another thread. here is the comparison updated

the following is the history of 1992 Andrew and 2005 Irene (history so far). the bolded text is Irene's current position and Andrews postion closest to the same longitude. Note that Andew at the same longitude is approximately 300 miles south of Irene, containing winds 20mph faster and pressure 5mb lower.

Irene:

21 GMT 08/04/05 12.7N 34.5W 30 1009 Tropical Depression
03 GMT 08/05/05 13.0N 35.2W 30 1009 Tropical Depression
09 GMT 08/05/05 14.4N 36.1W 30 1009 Tropical Depression
15 GMT 08/05/05 16.4N 37.3W 30 1010 Tropical Depression
21 GMT 08/05/05 17.0N 39.1W 30 1010 Tropical Depression
03 GMT 08/06/05 17.6N 40.6W 30 1010 Tropical Depression
09 GMT 08/06/05 17.7N 41.7W 35 1008 Tropical Depression
15 GMT 08/06/05 17.9N 42.3W 35 1008 Tropical Depression
21 GMT 08/06/05 19.0N 43.2W 35 1008 Tropical Depression
03 GMT 08/07/05 18.9N 44.3W 35 1008 Tropical Depression
09 GMT 08/07/05 19.6N 44.7W 35 1007 Tropical Depression
15 GMT 08/07/05 20.5N 45.5W 40 1005 Tropical Storm
21 GMT 08/07/05 21.1N 46.5W 40 1005 Tropical Storm
03 GMT 08/08/05 21.5N 47.7W 40 1005 Tropical Storm
09 GMT 08/08/05 21.9N 48.9W 40 1006 Tropical Storm
15 GMT 08/08/05 22.4N 50.7W 35 1009 Tropical Depression
21 GMT 08/08/05 22.5N 51.5W 35 1009 Tropical Depression
03 GMT 08/09/05 22.6N 52.7W 35 1009 Tropical Depression
09 GMT 08/09/05 22.5N 53.6W 35 1009 Tropical Depression
15 GMT 08/09/05 22.3N 53.9W 35 1009 Tropical Depression
21 GMT 08/09/05 22.6N 54.4W 35 1008 Tropical Depression
03 GMT 08/10/05 22.4N 55.5W 35 1008 Tropical Depression
09 GMT 08/10/05 22.4N 57.3W 30 1010 Tropical Depression

Andrew:

18 GMT 8/16/92 10.8N 35.5W 30 1010 Tropical Depression
0 GMT 8/17/92 11.2N 37.4W 35 1009 Tropical Depression
6 GMT 8/17/92 11.7N 39.6W 35 1008 Tropical Depression
12 GMT 8/17/92 12.3N 42.0W 40 1006 Tropical Storm
18 GMT 8/17/92 13.1N 44.2W 40 1003 Tropical Storm
0 GMT 8/18/92 13.6N 46.2W 45 1002 Tropical Storm
6 GMT 8/18/92 14.1N 48.0W 50 1001 Tropical Storm
12 GMT 8/18/92 14.6N 49.9W 50 1000 Tropical Storm
18 GMT 8/18/92 15.4N 51.8W 50 1000 Tropical Storm
0 GMT 8/19/92 16.3N 53.5W 50 1001 Tropical Storm
6 GMT 8/19/92 17.2N 55.3W 50 1002 Tropical Storm
12 GMT 8/19/92 18.0N 56.9W 50 1005 Tropical Storm
18 GMT 8/19/92 18.8N 58.3W 50 1007 Tropical Storm
0 GMT 8/20/92 19.8N 59.3W 45 1011 Tropical Storm
6 GMT 8/20/92 20.7N 60.0W 45 1013 Tropical Storm
12 GMT 8/20/92 21.7N 60.7W 45 1015 Tropical Storm
18 GMT 8/20/92 22.5N 61.5W 45 1014 Tropical Storm
0 GMT 8/21/92 23.2N 62.4W 50 1014 Tropical Storm
6 GMT 8/21/92 23.9N 63.3W 50 1010 Tropical Storm
12 GMT 8/21/92 24.4N 64.2W 60 1007 Tropical Storm
18 GMT 8/21/92 24.8N 64.9W 60 1004 Tropical Storm
0 GMT 8/22/92 25.3N 65.9W 65 1000 Tropical Storm
6 GMT 8/22/92 25.6N 67.0W 75 994 Category 1 Hurricane
12 GMT 8/22/92 25.8N 68.3W 90 981 Category 1 Hurricane
18 GMT 8/22/92 25.7N 69.7W 105 969 Category 2 Hurricane
0 GMT 8/23/92 25.6N 71.1W 125 961 Category 3 Hurricane
6 GMT 8/23/92 25.5N 72.5W 150 947 Category 4 Hurricane
12 GMT 8/23/92 25.4N 74.2W 165 933 Category 5 Hurricane
18 GMT 8/23/92 25.4N 75.8W 170 922 Category 5 Hurricane
0 GMT 8/24/92 25.4N 77.5W 145 930 Category 4 Hurricane
6 GMT 8/24/92 25.4N 79.3W 150 937 Category 4 Hurricane
12 GMT 8/24/92 25.6N 81.2W 130 951 Category 3 Hurricane
18 GMT 8/24/92 25.8N 83.1W 135 947 Category 4 Hurricane
0 GMT 8/25/92 26.2N 85.0W 135 943 Category 4 Hurricane
6 GMT 8/25/92 26.6N 86.7W 135 948 Category 4 Hurricane
12 GMT 8/25/92 27.2N 88.2W 140 946 Category 4 Hurricane
18 GMT 8/25/92 27.8N 89.6W 145 941 Category 4 Hurricane
0 GMT 8/26/92 28.5N 90.5W 145 937 Category 4 Hurricane
6 GMT 8/26/92 29.2N 91.3W 140 955 Category 4 Hurricane
12 GMT 8/26/92 30.1N 91.7W 90 973 Category 1 Hurricane
18 GMT 8/26/92 30.9N 91.6W 60 991 Tropical Storm
0 GMT 8/27/92 31.5N 91.1W 40 995 Tropical Storm
6 GMT 8/27/92 32.1N 90.5W 35 997 Tropical Depression
12 GMT 8/27/92 32.8N 89.6W 35 998 Tropical Depression
18 GMT 8/27/92 33.6N 88.4W 30 999 Tropical Depression
0 GMT 8/28/92 34.4N 86.7W 25 1000 Tropical Depression
6 GMT 8/28/92 35.4N 84.0W 25 1000 Tropical Depression

[weatherwindow]

i think the key to andrew's eventual renaissance was the maintenance of a vigorous mid level circulation. it permitted the system to survive the bouts of shear....my question: do we see any evidence of such a circulation with irene?...in its absence, i believe that irene could not survive even another 6 hours of 30kt shear. that said, irene has looked pathetic before and has persisted. as mentioned in the 500am discussion, irene's saving grace has been the repeated reformation of its center into the convection. perhaps, the "little depression that could" will again ..................rich

[dixiebreeze]

Well, she's looking mighty fine this morning, even starting to band. She looks like a survivor:

http://www.ssd.noaa.gov/PS/TROP/DATA/RT ... IR4/20.jpg

[dixiebreeze]

On the loop, it looks to me like a pretty clear spin and decent outflow:

http://www.ssd.noaa.gov/PS/TROP/DATA/RT ... -loop.html

[WeatherEmperor]

yes it does dixie. only gonna get stronger.

<RICKY>

[beachbum_al]

Anything with the name Andrew (except the member Andrew92) gives me chills. I just keep remember the night that my room mate in college and I sat up and watch the news as she worried about her family back home. And then not being able to get in touch with them until a day later.

[WeatherEmperor]

I just love these Andrew comparisons. They are so great

<RICKY>

[Andrew92]

Anything with the name Andrew (except the member Andrew92) gives me chills. I just keep remember the night that my room mate in college and I sat up and watch the news as she worried about her family back home. And then not being able to get in touch with them until a day later.

Thanks, I appreciate that. There are good people in the world named Andrew....my given name is Andrew, hence my screen name here (though in the real world I more typically go by the shortened Andy). Although I only pick 92 because that was the year of the storm, otherwise it isn't when I was born or graduated or anything.

Just our storm was bad. Nothing we could do about it.

-Andrew92

[du1st]

Read the 5am dissucion!

[dixiebreeze]

Read the 5am dissucion!

The 5 a.m. discussion will be greatly amended at the next update.

[dwg71]

Irene is not an Andrew, not in path and not in intensity, IMO... and this will not be a south Florida storm. If, and I still say it wont make landfall in US, it does come ashore in US it will be NC. But again I dont see it making it to the US.

[TPACane04]

great pickup Dixie...I read the very same thing this morning, prior to seeing your thread.

The stunning thing about Andrew was the unheard-of RI once he kicked in...dropping something like 75 mb in a very short time.

Not saying this is going to happen with Irene, but I would be very curious to see what happens once the ridge sets and she begins a palpable westward motion with no shear.

sat presentation looks better this morning, but I am being pessimistic until Thursday afternoon...needs that long to stoke the engines, if they are to be stoked at all.

[dixiebreeze]

Yes, TPAcane, I think Irene will be a lot more interesting to observe than many previously thought.