Close-in Development-Worst Case Scenario ?

[OuterBanker]

Is the worst case scenario an in close development.
I was reviewing the year 2004 and remembered just how close we avoided a tragedy.
Because of all the land falling hurricanes that year Alex was really never discussed.
Alex formed from a cluster of showers that combined with a tropical wave just east of the Bahamas and headed NW toward the coast. East of Jacksonville it was called a td. One Aug 1 at 18z it became Alex with 35 kt winds and 1009 mb. On Aug 3 18z (48 hrs) it was a 972 mb Cat 2 glancing off Cape Hatteras (9 mi off Hatteras). It flooded hundreds of cars and scared a lot of tourists on Hatteras Island and Ocracoke. He then went ENE harmlessly out to sea. What was also interesting is that it became a major hurricane at one of the highest latitudes (38.5) ever recorded.
This country got very lucky.
A what if could have been very tragic.
A NNE heading instead of ENE would have meant a strengthening, accelerating tropical system heading up the coast of one of the most heavily populated areas of the country.
No time for preparation. No time for evacuations. A tragedy that would hit so fast that most would have little time to react. A potential disaster.

JMO, mets tell me I'm crazy and this can't happen.

[vbhoutex]

Well stated. This is not a wishcast scenario. It is a possibility. I hope it never happens because I think your observations are spot on.

[RL3AO]

Humberto with 12 more hours over water hitting Houston would be up there too.

[vbhoutex]

Humberto with 12 more hours over water hitting Houston would be up there too.

Yes he would have been if he had continued his rate of intensification and had 12 more hours over water. If that had happened with a track more N or NW it would have been an incredibly nasty experience for the Houston metro area imo. It was bad enough for the rest of SE TX as it was.

[Macrocane]

Humberto with 12 more hours over water hitting Houston would be up there too.

Yeah that kind of happened with Ike, didn't it?

[CrazyC83]

Humberto with 12 more hours over water hitting Houston would be up there too.

Yeah that kind of happened with Ike, didn't it?

At least no one was surprised Ike was coming, they had plenty of time to prepare. Not so with Humberto.

Another worst-case would be if Katrina had 12 more hours of water before hitting South Florida (the forgotten first landfall).

[Macrocane]

At least no one was surprised Ike was coming, they had plenty of time to prepare. Not so with Humberto.

Well, that's true, if I remember well not even the models predicted the development of Humberto.

[vbhoutex]

Humberto with 12 more hours over water hitting Houston would be up there too.

Yeah that kind of happened with Ike, didn't it?

Not that I remember. The question with Ike was whether or not he was going to make CAT3 status which he had plenty of time to do. If he had come in about 20-30 miles further West than he did he would have had at least several more hours over some very warm water and I think we would have been in a much nastier scenario that we were(and I don't care for another 6 hour "ride" in an eyewall thank you).

[CrazyC83]

At least no one was surprised Ike was coming, they had plenty of time to prepare. Not so with Humberto.

Well, that's true, if I remember well not even the models predicted the development of Humberto.

Everyone - the NHC, every computer model, every outside forecaster, you and I and others here - bombed badly on Humberto. He sure defied everyone's expectations...

[vbhoutex]

At least no one was surprised Ike was coming, they had plenty of time to prepare. Not so with Humberto.

Well, that's true, if I remember well not even the models predicted the development of Humberto.

Everyone - the NHC, every computer model, every outside forecaster, you and I and others here - bombed badly on Humberto. He sure defied everyone's expectations...

I'm not sure I know of anyone that predicted Humberto to do what he did. I know I sure didn't.

[Hurricanehink]

What's worst with Alex is that in the first advisory it was only forecast to peak at 40 kt. Not until 25 hours before it attained hurricane status was that even predicted. The key thing about Alex is that it was in the TWO for three days, and there was an explicit mention of the potential for TD formation for two days.

A similar situation from 2004 that I'm surprised wasn't mention was Gaston. It formed and struck land as a hurricane within two days, but hurricane status wasn't predicted until 9 hours before landfall (and only 40 kt peak was predicted in the first 18 hours). Unlike Gaston, this was the TWO only 12 hours before it formed.
http://www.nhc.noaa.gov/archive/text/TWOAT/2004/TWOAT.200408270235 I just want to point out how it says "there are no signs of development at this time", only 12 hours before it formed.

IMO, storms that have a 50% chance of developing should get some sort of advisory. If they thing the chance for developing is that good, they should make some sort of forecast. It wouldn't need to be a full product, but a basic public advisory, estimating how strong it could be and where it would go. I'll never forget how the NHC mentioned the possibility for Wilma becoming a hurricane before they even started advisories. (http://www.nhc.noaa.gov/archive/text/TWOAT/2005/TWOAT.200510151507)

Such a system of issuing some sort of advisory for rapidly developing storms near the coast wouldn't help for Gaston or Humberto, unfortunately (the latter had this lackluster TWO - http://www.nhc.noaa.gov/archive/text/TWOAT/2007/TWOAT.200709120920.txt).

However, it would help for those storms that make landfall less than two days before forming, such as Tomas (which developed 24 hours before striking Lesser Antilles, but was at 50% about 12 hours before that), Agatha (which developed 8 hours before hitting Guatemala, but was at 50% for 48 hours before that), and Noel (which hit land about 24 hours after developing, but 12 hours before that had the wording of "any increase in organization..."). After all, it isn't that often that a disturbance gets the high potential category and not develop. Most of the time it would be for systems far away from land, although clearly not always the case. Imagine if the people affected by the three above storms got even 12 hours more notice.

[hurricanehunter69]

I remember the ominous 48 hours prior to, and the mandatory evac of Katrina....The mayor of New Orleans stated on television that he was ordering 10,000 body bags.....Just imagine if Katrina would have not weakened to cat 3 strength at landfall and instead maintained itself and smashed in at maximun cat 5 strength....? The results could have been more horrific than I think most of us are willing to imagine.

[LSU2001]

As bad as Katrina was, she could have been much worse. If she had tracked slightly west of NOLA say over Timbalier/Barataria bay area, the full brunt of the surge and winds would have hit NOLA. This would have been a worst case scenario and the toll would have been much worse. The thing that worries me about Katrina is that people in South Louisiana now mark Katrina as the benchmark of storms. In Louisiana this isn't even close to what a major hurricane can really do. I think people forget that the damage to NOLA was largely due to poor levee design and poor levee maintenance.
Katrina, in NOLA, was a man made disaster brought on by natural forces. The Mississippi gulf coast saw the full fury of the storm and New Orleans only had a glancing blow. Considering what could have been I feel we were lucky Katrina was not the worst case.

Just my 2 cents,
Tim

[Flyinman]

I was living in Beaumont when Humberto hit. One of our long time local mets did mention on the 10:00 news that this was showing some signs of development but it was too late to sound any alarm. Everyone was going to have to ride this one out. Well, at 1:00 am I awoke to branches hitting my windows and very stong winds with gusts close to 100 mph. They eye came over the house. Just to show how small this storm was, we went to check on our beach house and there was damage in High Island and further West down Hwy 87. However, at our house, about 10 miles West of High Island, our furniture had not even moved on the deck.

[srainhoutx]

Humberto with 12 more hours over water hitting Houston would be up there too.

Yeah that kind of happened with Ike, didn't it?

Another worst-case would be if Katrina had 12 more hours of water before hitting South Florida (the forgotten first landfall).

This is the situation I found myself in in living the Lower Keys. If folks will recall Katrina was forecast to move W across mainland FL and certainly not be an issue for the Keys. After landfall near the Broward/Miami Dade County lines, that WSW motion began. The next morning the center of Katrina was in Floida Bay, 40 miles to my N and we had almost waist deep water from rainfall.

[MGC]

RI close to land is a big threat....remember Charley in 2004? From a Cat-2 to nearly a Cat-5 in only a few hours just off shore....Yikes......MGC

[StarmanHDB]

Another worst-case would be if Katrina had 12 more hours of water before hitting South Florida (the forgotten first landfall).

For as "forgotten" as Katrina's first landfall was, no one should forget that she was responsible for 14 deaths in South Florida thus proving that ALL tropical weather, no matter how "uneventful" it may seem at the time, must be respected.

[jinftl]

It's one thing staring down the barrel of a developed Cat 5 that is closing in on you....what would happen if instead 36 hours out, it was just a tropical storm with potential to rapidly intensify? What if Katrina was a tropical storm on Sunday morning instead of a Cat 5? What if Katrina then went through a rapid intensification to a Cat 3 or 4 by landfall in Buras Monday morning? Would people have taken the threat of a 'potential catastrophic hurricane' as seriously as an approaching already-formed Cat 5?

In my opinion, that is the scariest scenario...a storm like the Labor Day hurricane of 1935. Went from a TS to a Cat 5 in 36 hours. The Florida Keys takes time to evacuate - would officials call for a mandatory evacuation for a t.s. that could become a major hurricane by landfall? Probably. Would residents and visitors heed the calls to leave if they turn on the news and see 'just a tropical storm' 36 hours out? Doubtful.

In other words- will a hurricane warning issued on a storm that is still a developing tropical storm with the potential to intensify prior to landfall elicit the same response from officals and citizens as a hurricane warning issued on an already developed Cat 4 or 5?

[Andrew92]

Reading this topic, what if a storm bombed as rapidly as Wilma did right before a landfall? I shudder thinking about it.

-Andrew92

[jinftl]

Was Katrina’s un-realized nightmare scenario the Florida Keys? It seems that way based on the facts…

You only have to look at the NHC Advisory Discussions as Katrina approached South Florida to see the uncertainty forecasters had not only over the potential intensity upon landfall in florida, but even the track. The model that predicted a WSW track across extreme south florida and the Keys just 24 hours before landfall was deemed ‘unrealistic at this time’ from the discussion excerpted below. Reality check - that is essentially the track that actually happened.

And, if Katrina had 6 or more additional hours…which a few less mph in speed could easily have provided…off the coast of South Florida before landfall, she may have been a Cat 2. Easily. The pressure dropped 12 mb in the 6 hours leading up to landfall on the Miami-Dade/Broward line. She was intensifying in a hurry.

Given her track of little time over land (which forecasters got wrong as you will see below), she could have been a strong Cat 1 impacting the Lower Keys. It should be noted that 12-18 hours before the Lower Keys got strong tropical storm conditions (Dry Tortugas may have briefly had sustained hurricane winds even), there was not even a Tropical Storm Watch posted.

The uncertainty of forecast intensity and track close to landfall shows a potential nightmare for the Keys was averted...this time. it is somewhat disconcerting to see NHC Discussions of the, per their own words, "outstanding GFDL model consistently showing a strong hurricane moving wsw across the Keys" 24 hours before the Keys were impacted...and it took another 18 hours for a Tropical Storm Warning to be issued for the Lower Keys....6 or so hours before the storm hit there.


NHC Advisory Discussion on Katrina 24-30 hours from South Florida landfall:
TROPICAL STORM KATRINA DISCUSSION
5 PM EDT WED AUG 24 2005

WITH THE IMPROVED BANDING FEATURES...SYMMETRICAL UPPER-LEVEL OUTFLOW
...AND RELATIVELY WEAK SHEAR...AT LEAST STEADY INTENSIFICATION OF A
NORMAL RATE OF 10 KT PER 12 HOURS UNTIL LANDFALL OCCURS SEEMS
JUSTIFIED. THIS IS SIMILAR TO THE SHIPS INTENSITY MODEL...BUT MUCH
LESS THAN THE NOW VERY BULLISH GFDL MODEL WHICH BRINGS KATRINA TO
111 KT JUST BEFORE LANDFALL. IT SHOULD BE POINTED OUT THAT WITH
SSTS NEAR 31C AND A LOW SHEAR ENVIRONMENT...CONDITIONS ARE
FAVORABLE FOR POSSIBLE RAPID INTENSIFICATION TO OCCUR BETWEEN NOW
AND LANDFALL. THIS IS SUGGESTED BY THE SHIPS MODEL EXPERIMENTAL
RAPID INTENSIFICATION OUTPUT...WHICH INDICATES A 57 PERCENT
PROBABILITY OF THAT OCCURRING. THE ONLY INHIBITING FACTOR IS THE
DRY AIR THAT SURROUNDS KATRINA AND HAS BEEN WORKING ITS WAY INTO
THE INNER-CORE REGION AND ERODING THE DEEP CONVECTION. IF THE DRY
AIR MIXES OUT WITHIN THE NEXT 12 HOURS...THEN INTENSITIES WOULD
LIKELY BE HIGHER THAN THE OFFICIAL FORECAST IS INDICATING.



NHC Advisory Discussion on Katrina 18-24 hours from South Florida landfall:
TROPICAL STORM KATRINA DISCUSSION
11 PM EDT WED AUG 24 2005

THIS FORECAST IS RATHER DIFFICULT SINCE ONE OF THE MORE
RELIABLE MODELS...THE GFS...SHOWS THAT THE CYCLONE BARELY TOUCHES
THE EAST COAST OF FLORIDA BEFORE MOVING NORTHWARD....WHILE THE
OUTSTANDING GFDL MOVES KATRINA SOUTH OF DUE WEST ACROSS EXTREME
SOUTH FLORIDA AND THE KEYS AS A VERY INTENSE HURRICANE. THE GFDL
SCENARIO WOULD BE VERY DANGEROUS FOR SOUTH FLORIDA. THIS APPEARS TO
BE UNREALISTIC AT THIS TIME BUT BECAUSE OF THE GOOD PAST
PERFORMANCE OF THIS MODEL...WE MUST PAY CLOSE ATTENTION TO FUTURE
MODEL RUNS.



NHC Advisory Discussion on Katrina 6-12 hours from South Florida landfall
– at this time there was only a Tropical Storm Watch in effect for the Middle and Upper Keys. No watches or warnings were in effect for the Lower Keys:

TROPICAL STORM KATRINA DISCUSSION
11 AM EDT THU AUG 25 2005

THE OFFICIAL FORECAST TRACK IS SIMILAR TO THE
PREVIOUS TRACK AND IS CLOSE TO THE NHC MODEL CONSENSUS AFTER 48
HOURS. THE GFDL MODEL HAS BEEN CONSISTENTLY FORECASTING A
SOUTHWESTWARD MOTION AROUND THE SOUTHERN END OF FLORIDA FOR THE
PAST 24 HOURS. WHILE THIS TRACK IS CERTAINLY POSSIBLE TO SOME
DEGREE...MY CURRENT THINKING IS THAT THE GFDL IS TAKING KATRINA TOO
FAR SOUTH THROUGH THE FLORIDA KEYS AS A MAJOR HURRICANE


As Katrina was about to make landfall in south florida, the NHC Advisory Discussion of even what would actually transpire was quite from what actually happened – Katrina did not spend 30 hours over land…she spent 7 or 8, as the sw motion that the GFDL model showed actually transpired. The Lower Keys went from being under no watch or warning at 11am to being under a tropical storm warning 6 hours later with this advisory.

HURRICANE KATRINA DI SCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT THU AUG 25 2005

AT 5 PM EDT...A TROPICAL STORM WARNING HAS BEEN ISSUED FOR ALL OF
THE FLORIDA KEYS AND FLORIDA BAY FROM KEY WEST NORTHWARD. A
TROPICAL STORM WARNING HAS ALSO BEEN ISSUED ALONG THE GULF COAST OF
FLORIDA FROM LONGBOAT KEY SOUTH AND EASTWARD TO SOUTH OF FLORIDA
CITY.

AFTER LANDFALL
...STEADY WEAKENING IS EXPECTED UNTIL THE HURRICANE EMERGES OFF THE
SOUTHWEST FLORIDA COAST IN ABOUT 30 HOURS. ONCE KATRINA MOVES OVER
THE WARM GULF OF MEXICO WHERE THE VERTICAL SHEAR IS EXPECTED TO BE
LOW...RESTRENGTHENING INTO A HURRICANE SEEMS LIKELY.



12 hours later, Katrina was a hurricane 50 miles n-ne of Key West and moving west to w-sw.
At no point was Key West under a hurricane warning. Under more predictable circumstances, there is no way the lower Keys wouldn’t have been under a hurricane warning for such an actual storm track and intensity.

HURRICANE KATRINA ADVISORY
5 AM EDT FRI AUG 26 2005

...KATRINA REGAINS HURRICANE STATUS OVER THE GULF OF MEXICO...

AT 5 AM EDT...0900Z...THE CENTER OF HURRICANE KATRINA WAS LOCATED
NEAR LATITUDE 25.3 NORTH... LONGITUDE 81.5 WEST OR ABOUT 50
MILES... 85 KM... NORTH-NORTHEAST OF KEY WEST FLORIDA