Atlantic Hurricane/Invest Thread 2012/2013

[Gray-Wolf]

My wishful thinking has 97L becoming our first 'cane of the (delayed) season? seems to be having a go at growing itself into a very large disturbance too? Any guidance as to where it's bound once the Caribbean has formed it? 

[Summer Sun]

Roger J Smith has updated his blog on the slow start to start to the hurricane season

 

http://www.gavsweathervids.com/rogerjsmith.html

[summer blizzard]

My wishful thinking has 97L becoming our first 'cane of the (delayed) season? seems to be having a go at growing itself into a very large disturbance too? Any guidance as to where it's bound once the Caribbean has formed it? 

 

At 1800 UTC, 01 September 2013, LOW INVEST (AL97) was located in the North Atlantic basin at 14.6°N and 59.7°W. The current intensity was 30 kt and the center was moving at 7 kt at a bearing of 270 degrees. The minimum central pressure was 1008 mb.

 

1. A WELL-DEFINED LOW PRESSURE SYSTEM IS LOCATED ABOUT 100 MILES EAST

OF THE CENTRAL LESSER ANTILLES. SATELLITE IMAGERY INDICATES THAT

THE ASSOCIATED THUNDERSTORM ACTIVITY HAS INCREASED AND IS SHOWING

SIGNS OF ORGANIZATION. UPPER-LEVEL WINDS ARE QUITE CONDUCIVE...

BUT PROXIMITY TO DRY AIR IN THE MIDDLE- AND UPPER-LEVELS OF THE

ATMOSPHERE COULD INHIBIT DEVELOPMENT OF THIS DISTURBANCE. THIS

SYSTEM HAS A MEDIUM CHANCE...40 PERCENT...OF BECOMING A TROPICAL

CYCLONE DURING THE NEXT 48 HOURS...AND A MEDIUM CHANCE...50

PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 5 DAYS

WHILE IT MOVES WESTWARD AT 10 TO 15 MPH ACROSS THE CARIBBEAN SEA.

REGARDLESS OF WHETHER OR NOT A TROPICAL CYCLONE FORMS...LOCALLY

HEAVY RAINFALL AND STRONG GUSTY WINDS ARE EXPECTED TO AFFECT

PORTIONS OF THE LESSER ANTILLES TODAY THROUGH MONDAY.

 

 

 

 

 

Reminds me vaguely of Gustav..

 

[summer blizzard]

ATLANTIC SHIPS INTENSITY FORECAST *
* GOES AVAILABLE, OHC AVAILABLE *
* INVEST AL972013 09/01/13 18 UTC *

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 30 34 38 42 46 54 63 70 76 81 85 86 87
V (KT) LAND 30 34 38 42 46 54 63 70 76 81 85 86 87
V (KT) LGE mod 30 33 36 40 44 52 63 75 87 98 106 109 109
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

[lorenzo]

Atlantic is a real slow burner this year.

 

Some interest in this topographically challenged system, a 30% chance then a 50:50 into day 5 of reaching Tropical Cyclone Status.

 

[be cause]

..                 yawn .. 

[be cause]

more seriously though .. last year .. before I found here ,I found I found the amazingly good (for newbe me) site .. stormadvisory.org and they are up at the top of my fav. pages .. but .. Has it all gone ? I had intended to spend winter evenings researching the paths and power and parallels of past storms and what I thought the best toy I had found on the net just disappeared . Thought it might come back .. I say no to Atlantic storms until I have my toy back !  Help !

[summer blizzard]

This looks like TD7 to me.

[Coast]

..                 yawn .. 

 

 

 

Zero hurricanes at midway point, but threat remains for busy Atlantic hurricane season

 

Nearly one year after superstorm Sandy devastated the Northeast, this year’s hurricane season has reached its halfway point without a single storm forming. Still, federal forecasters are warning of an unusually active and potentially dangerous few months to come. Last month, the National Oceanic and Atmospheric Administration updated its hurricane season forecast, trimming back the number of hurricanes expected this year to between six and nine. That's a few less than they predicted in May. The updated forecast calls for three to five of those hurricanes to be major, with winds greater than 110 mph. The updated forecast also predicts 13 to 19 named storms this year.

 

The chance that 2013 will be busier than normal remains at 70 percent. A normal year has 12 named storms, six hurricanes and three major storms. Gerry Bell of NOAA's Climate Prediction Center in College Park, Md., said in August that he is still predicting a busier-than-normal season because of larger climate patterns that have been in place since about 1995. Atlantic waters are warmer than normal, wind patterns are just right, and there has been more rain in West Africa. This fits with a larger 25-to-40-year cycle of hurricane activity that meteorologists have seen over the decades.

 

He told FoxNews.com in an email Thursday that there is no update to the August report. The forecasts don't include where storms might land, if any place. Despite the formation of more hurricanes recently, the last time a major hurricane made landfall in the United States was Wilma in 2005. That seven-and-a-half-year stretch is the longest on record. It's also the last time any size hurricane made a direct hit on Florida, which is also a record, said National Hurricane Center spokesman Dennis Feltgen, who told Yahoo News that Hurricane Andrew in 1992 was the season’s first hurricane and it caused catastrophic damage to Miami.

 

But just because a storm is not technically classified major with 111 mph winds or more, doesn't mean it can't do lots of damage. Sandy is evidence of that, Bell said. The storm caused hundreds of miles of flooding, killing 147 people and causing $50 billion in damage. Hurricane season starts in June and runs until the end of November, but peak hurricane season runs from mid-August to mid-October. David Sinclair, who owns a waterfront tiki bar in North Carolina, told Yahoo News, "Don't ever drop your guard until we’re through September. Now through September is when the bigger ones really start flying off the hook.

 

 

http://www.foxnews.com/weather/2013/09/03/zero-hurricanes-at-midway-point-but-threat-for-busy-atlantic-hurricane-season/#ixzz2dubCC2Xu

[summer blizzard]

Recon is in there now. In the meantime it has been upped to 50% within 2 days and 60% within 5 days. It is currently absorbing the wave behind it although i'd say if anything that has just fed it more energy.

 

 

http://radar.weather.gov/radar.php?rid=JUA&product=NCR&overlay=11101111&loop=yes

Edited September 4, 2013 by summer blizzard

[summer blizzard]

19:30:30Z 17.000N 65.550W 970.0 mb
(~ 28.64 inHg) 353 meters
(~ 1,158 feet) 1010.4 mb
(~ 29.84 inHg) - From 99° at 38 knots
(From the E at ~ 43.7 mph) 21.5°C
(~ 70.7°F) 21.5°C
(~ 70.7°F) 40 knots
(~ 46.0 mph) 65 knots
(~ 74.8 mph) 31 mm/hr
(~ 1.22 in/hr) 61.8 knots (~ 71.0 mph)
Tropical Storm 162.5% 

 

Very broad center (either due to its beginnings or elongation as it absorbs the wave behind) which is why pressure is pretty high but winds are at tropical storm force. With deep convection firing over the center it's touch and go as to whether they want to declare it or wait for it to deepen. 

[summer blizzard]

  

 

Appears i was correct, we do officially have Tropical Depression 7.

 

BEGIN
NHC_ATCF
invest_RENUMBER_al972013_al072013.ren
FSTDA
R
U
040
010
0000
201309042009
NONE
NOTIFY=ATRP
END

 

[lorenzo]

Good shout SS, it was touch and go for a bit but eventually made it. Advisory updated now. http://www.nhc.noaa.gov/graphics_at2.shtml?gm_track#contents

 

 

 

 

http://radar.weather.gov/ridge/radar.php?rid=JUA&product=N0R&overlay=11101111&loop=yes

 

Some 18z model guidance courtesy of the good Dr. on Twitter.

 

[Coast]

Good shout SS, it was touch and go for a bit but eventually made it. Advisory updated now. http://www.nhc.noaa.gov/graphics_at2.shtml?

 

She looks unlikely to make it to a 'cane though:

 

http://forum.netweather.tv/topic/77765-tropical-depression-7/?p=2781076

[summer blizzard]

Just created my own forecast for the season using primarily the years of 1990, 1995 and 2004 as analogues.

 

My prediction is 16/9/4.

 

 

At 6/0/0 to the half way mark something tells me my forecast was a bust.

[Sainsbo]

The invest just north west of the Yukatan Peninsula could become a tropical depression before landfall. NHC currently saying it's 50%, but it looks like it is becoming more organised. A recon has been sent to investigate it.

 

 

Landfall isn't that far away, so if it's going to intensify, it better do so quickly.

[Coast]

Still no hurricanes?

 

We have reached September 5 and still have not had a hurricane in the Atlantic.  While not a record, it’s getting close. Before diving into the records, let’s think about what we’re really measuring.  The boundary between a tropical storm and a hurricane is hard to accurately measure.  It’s a matter of distinguishing between sustained winds (found anywhere in the storm) of 60kts and 65kts.  All other features can be virtually identical, but that single number determines its status.

 

Even with aircraft reconnaissance, that measurement can be uncertain.  The aircraft will sample the storm as thoroughly as possible, but there are limitations to coverage and to diagnosing winds at the surface.  While aircraft have been used to reconnoiter tropical cyclones in the Atlantic for about 70 years, they can only reach storms in the western part of the basin, and are not flying into storms continuously.

 

Then along comes the satellite era in the early 1960s.  The satellite era is much more reliable and accurate when it comes to tropical cyclone climatology.  While technology has improved the instruments aboard the satellites over the years, having around-the-clock images of the entire basin has made the record much more robust during this entire period. So, using the best available data we have and going back 50 years (1963), the latest date of first hurricane formation is September 11, and that occurred in 2002 with Gustav.  The latest five dates during this period are:

 

September 11: Gustav (2002)

September 10: Diana (1984)

September 9: Erin (2001)

September 3: Arlene (1967)

September 2: Debby (1988)

 

You can see that even if Gabrielle became a hurricane today, it would still be in fourth place.

All fifty dates of first hurricane formation are shown in the charts below.  Some dates have had multiple instances of the season’s first hurricane forming. August 22 has had four.  To see how variable these dates are in time, the second chart plots the same data but by year rather than by date.  The median date of first hurricane formation is August 6 and is marked with a green line in both charts.

 

 

In those five years with the latest first hurricanes, it’s of course interesting to look at how active they turned out to be.  The table below summarizes the ACE (Accumulated Cyclone Energy) as well as any major hurricanes that occurred.  And by the way, 2013′s ACE is now down to 21 percent of normal for this date.

 

YEAR    ACE                            MAJOR HURRICANES

 

2002    67 (below normal)       Isidore, Lili

1984    84 (near normal)          Diana

2001    110 (near normal)        Erin, Felix, Iris, Michelle

1967    122 (above normal)     Beulah

1988    103 (near normal)        Gilbert, Helene, Joan

 

It’s quite possible that Gabrielle will never reach hurricane status, and the clock will keep ticking.  There are three other areas of interest scattered across the basin this morning, but none of them pose the imminent threat of developing into a named storm.

 

 

http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2013/09/05/tropical-storm-gabrielle-brushes-puerto-rico-still-no-hurricanes/

[Sainsbo]

Very interesting read Coast.  I wasn't aware that this season was anything other than just rather quiet, not potentially record breaking.

 

 

Not looking too good for 99L now. While it was looking good last night, it is still at a 50% chance this morning, and there isn't long before landfall.

[summer blizzard]

The system in the Gulf has become Tropical Depression 8 but is now making landfall.

[Coast]

Very interesting read Coast.  I wasn't aware that this season was anything other than just rather quiet, not potentially record breaking.

 

Same here. It will be very interesting to see what transpires over the next few weeks and what effect it has on weather in the Americas over the Winter.

[Sainsbo]

The system just off of the coast of Africa has 20% chance of development in 48 hours, but an 80% chance in the next 5 days.

[Summer Sun]

If no hurricanes develop by Thursday (12th) we'll have a new record for the latest start to the Atlantic hurricane season which is currently September 11th

[summer blizzard]

The system just off of the coast of Africa has 20% chance of development in 48 hours, but an 80% chance in the next 5 days.[/quote

Now off the coast and already a mandarin.

Nhc also suggesting that another system could form in the Boc.

Stunningly 20 ensembles go for development of a wave near the Yukatan in around 2 weeks.

[Sainsbo]

TD Nine has formed, and looks like it possibly will become the first hurricane of the season.

 

[Coast]

 

Quiet Hurricane Season 2013 a ‘Head Scratcher’ for Embarrassed Forecasters

 

The 2013 Atlantic hurricane season, which forecasters had predicted would be more active than normal, has turned out to be something of a dud so far as an unusual calm hangs over the tropics. As the season heads into the historic peak for activity, it may even enter the record books as marking the quietest start to any Atlantic hurricane season in decades.

 

“It certainly looks like pretty much of a forecast bust,†said Jeff Masters, a hurricane expert and director of meteorology at the Weather Underground (www.wunderground.com). “Virtually all the (forecast) groups were calling for above-normal hurricanes and intensive hurricanes and we haven’t even had a hurricane at all, with the season half over,†he said.

 

With records going back to 1851, Dennis Feltgen, a spokesman for the U.S. National Hurricane Center, said there had been only 17 years when the first Atlantic hurricane formed after Sept. 4. The all-time record was set in 1905, he said, when the first hurricane materialized on Oct. 8. In an average season the first hurricane shows up by Aug. 10, usually followed by a second hurricane on Aug. 28 and the first major hurricane by Sept. 4.

 

Since the dawn of the satellite era in the mid-1960s, Feltgen said the latest date for the first hurricane to arrive was set by Gustav when it made its debut on Sept. 11, 2002. If this year’s first hurricane comes anytime after 8 a.m. EDT (1200 GMT) on Wednesday, it would replace Gustav as the modern-day record holder, Feltgen said. Seven named storms have been spawned by the 2013 season so far, including Fernand, which killed 13 people in central Mexico late last month. Most of the storms have been small, weak systems, however, proving an embarrassment to experts who had predicted an active season in reports that are eagerly awaited by the insurance and energy industries as well as many coastal homeowners.

 

“Statistical models can generally reasonably well replicate hurricane activity … but there are always going to be years when you bust,†said Phil Klotzbach, a Colorado State University climatologist who heads a team that issues one the most closely watched long-range hurricane forecasts. “We issue our final seasonal forecast in early August. But if we did put out a mid-season update, I would certainly back down from the prediction considerably,†he said.

 

Colorado State University slightly lowered its seasonal forecast on Aug. 2. But it still said 2013 would see above-average activity, with eight hurricanes and three that develop into major hurricanes of Category 3 or higher on the five-step Saffir-Simpson intensity scale. Other prominent forecasts, including the National Oceanic and Atmospheric Administration (NOAA), were predicting an “above normal†season last month. An average season has six hurricanes.

 

‘A HEAD SCRATCHER’

 

The jury is still out on what exactly has put such a damper this year over the Atlantic basin and the Caribbean, where tens of millions of people live in hurricane danger zones. Tuesday marks the statistical “peak day†of the season, which runs from June 1 through Nov. 30, and researchers say significant amounts of dry air and wind shear have helped keep a lid on hurricane formation. The El Nino weather phenomenon – a warming of the tropical Pacific – which is part of the mix of unstable ingredients that can affect hurricane formation, is also not a factor this year, making the lack of storm activity harder to explain.

 

“It’s certainly a head scratcher,†said Masters, who said he thought wind shear had been near normal this year and warmer than average sea temperatures in the Atlantic favored storms. He noted that dry air, from Africa as well as rarely mentioned flows associated with an extreme drought in northeast Brazil, may be a factor “helping to shut down this year’s hurricane season.â€

 

Forecasters say a system expected to emerge off the coast of Africa may strengthen into a hurricane by early next week. But whatever happens in the coming days, Feltgen cautioned it was still too early to write off 2013 as a year when tropical weather was unpredictable. “We are at mid-point of the six-month hurricane season,†he said. “It is a mistake to believe that the second half of the season would resemble the first half,†he said. The first hurricane in 2001, Erin, only formed on Sept. 9, Feltgen said. “That season ended with 15 named storms including nine hurricanes, four of which became major hurricanes.â€

 

 

 

http://www.insurancejournal.com/news/national/2013/09/09/304441.htm