Rina rapidly intensifies into a hurricane

By: Dr. Jeff Masters , 7:59 PM GMT on October 24, 2011

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Rina is now a hurricane, just 21 hours after becoming a tropical depression. An Air Force Reserve hurricane hunter aircraft found winds of 75 mph--Category 1 hurricane strength--at 1:40 pm EDT in the north eyewall of Rina, using their SFMR surface wind instrument. Winds at flight level of 5,000 feet peaked at 78 mph, which typically translates to surface winds of 62 mph. On their second pass through the eye at 3:30 pm EDT, the winds were about 5 mph less, but the central pressure had fallen by two millibars, to 989 mb. Visible satellite loops show that Rina now has an eye, and the storm is steadily expanding in size and developing an impressive upper-level outflow channel to the north. Wind shear is a moderate 15 - 20 knots due to strong upper-level winds out of the southeast, and these winds are injecting dry air into Rina's southeast side, inhibiting heavy thunderstorm development there. Water temperatures are very warm, 29 - 30°C, and these warm waters extend to great depth.


Figure 1. Afternoon satellite image of Rina. An intense thunderstorm with a top that reaches into the stratosphere is visible on the southwest side of the eye. These "hot towers" are commonly seen in hurricanes undergoing rapid intensification.

Rina in historical context
Rina intensified into a hurricane just 21 hours after the first advisory was issued for it as a tropical depression. This is the second fastest such intensification since record keeping began in 1851. Hurricane Humberto of 2007 holds the Atlantic record for fastest intensification from first advisory issued to hurricane strength--18 hours. (Actually, Humberto did the feat in 14 1/4 hours, but this was rounded off to 18 hours in the final data base, which stores points every six hours). There have been six storms that accomplished the feat in 24 hours. Rina's formation brings this year's tally of hurricanes to six, which is average for an Atlantic hurricane season. The number of named storms this season is now seventeen, making it the 7th busiest Atlantic hurricane season since record keeping began in 1851. Only 2005, 1933, 1995, 1887, 2010, and 1969 had more named storms. However, 2011 has had an unusually low percentage of its named storms reach hurricane strength. Only 35% of this year's named storms have made it to hurricane strength, and normally 55 - 60% of all named storms intensify to hurricane strength in the Atlantic. The rare combination of near-record ocean temperatures but unusually dry, stable air over the Atlantic is no doubt at least partially responsible for this very unusual occurrence.


Figure 2. Microwave satellite image from 11:39 am EDT October 24, 2011, showing that Rina had a partially complete eyewall, which was open on the east side. Image credit: Navy Research Lab, Monterey.

Forecast for Rina
The hurricane hunters found an elliptical eyewall that had a gap in it during their 3:30 pm eye penetration. The aircraft measured a temperature difference of 6°C between the eye and the region outside the eye, which is difficult to get unless an eyewall is on its way to completion. Rina will need to complete its eyewall if it is to intensify into a major hurricane. Given the fact wind shear is not expected to increase until Wednesday, Rina has a 2-day period to close off an eyewall and intensify, and it will probably reach Category 3 or Category 4 strength by Wednesday. On Wednesday, Rina will encounter a dry airmass with high wind shear that lies over the extreme northwestern Caribbean. These conditions should weaken the hurricane, but Rina could still be a major hurricane if it makes landfall in the Yucatan Peninsula on Wednesday or Thursday.

A trough of low pressure is predicted to pass to the north of Rina late this week, and now that the hurricane is expected to be a Category 2 or stronger storm, the chances for Rina to make it farther north and affect the Florida Keys and Southwest Florida have increased. The latest 8 am EDT runs of the GFDL and HWRF models both predict that Rina will pass through the Yucatan Channel on Thursday and make landfall on Friday in the Florida Keys or extreme Southwest Florida, south of Naples. The NOGAPS and GFS models predict a weaker storm, and keep Rina trapped in the Caribbean. I think it is more likely that Rina will pass through the Keys. If Rina does make it to the Keys, it would likely be as a tropical storm, since wind shear, dry air, and possible land interaction with Western Cuba and Mexico would potentially knock down the storm's strength. Heavy rains from Rina should begin affecting Mexico's Yucatan Peninsula, northern Belize, and extreme Western Cuba on Wednesday. Rina's intensification into a hurricane over the Western Caribbean during the last half of October bring to mind Hurricane Wilma, which also performed such a feat in 2005. Wilma went on to become a Category 5 monster, the strongest Atlantic hurricane of all-time. I don't think Rina will be another Wilma, even though the ocean temperatures and total heat content are similar to what Wilma experienced. Wilma had nearly ideal upper-level atmospheric conditions with an anticyclone aloft and light wind shear, under 5 knots. Rina is experiencing 15 - 20 knots of wind shear and is also a smaller storm, and is thus more vulnerable to the effects of wind shear and dry air.

97L approaching ABC islands
A broad region of low pressure approaching the ABC islands of Aruba, Bonaire, and Curacao (Invest 97L), is moving west-northwest at 10 mph. Heavy thunderstorm activity has increased today, but the activity is not organized into spiral bands, as is apparent from Curacao radar. 97L is surrounded by a large region of dry air, and this dry air will retard development. 97L is under low wind shear less than 10 knots, and this shear is expected to remain low through Thursday. By the time 97L reaches the region between Jamaica and Nicaragua in the Central Caribbean on Thursday or Friday, the storm should find a moister environment, and could develop into a tropical depression. However, none of the reliable models are predicting that 97L will develop. NHC is giving 97L just a 10% chance of developing into a tropical depression by Wednesday. I put the odds higher, at 20%.

Jeff Masters

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964. 7544
hmmmm new run here Link
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Member Since: March 19, 2009 Posts: 0 Comments: 1421
Quoting WoodyFL:
Most of the other models disagree with this


good morning, 59 here at 4am with clear skies, woody what are the chances of Rina coming thru the tampa bay area???
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Rina not moving much. Seems like the longer she sits down there the less likely she will be a S Fla storm. Temp in orlando forecast to be in 50's sat night. Front looks like its going to the straights. If so.......no Rina. Seems like some of the models (HWRF) are jumping on that bandwagon.
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960. 7544
shes looking good at this hour at dmax starting to blow up more looks like a cat 2 now imo

watching the blow up to the north being if she does head to fla and what effects will they have
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8 mb drop...
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Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 25th day of the month at 07:44Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 304)
Storm Number & Year: 18L in 2011
Storm Name: Rina (flight in the North Atlantic basin)
Mission Number: 3
Observation Number: 14
A. Time of Center Fix: 25th day of the month at 7:32:10Z
B. Center Fix Coordinates: 17°18'N 83°33'W (17.3N 83.55W)
B. Center Fix Location: 198 miles (319 km) to the SW (226°) from George Town, Cayman Islands (GBR).
C. Minimum Height at Standard Level: 2,901m (9,518ft) at 700mb
D. Estimated (by SFMR or visually) Maximum Surface Wind: 82kts (~ 94.4mph)
E. Location of the Estimated Maximum Surface Wind: 6 nautical miles (7 statute miles) to the NNE (28°) of center fix
F. Maximum Flight Level Wind Inbound: From 115° at 88kts (From the ESE at ~ 101.3mph)
G. Location of Maximum Flight Level Wind Inbound: 8 nautical miles (9 statute miles) to the NNE (30°) of center fix
H. Minimum Sea Level Pressure: 977mb (28.85 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 8°C (46°F) at a pressure alt. of 3,062m (10,046ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 16°C (61°F) at a pressure alt. of 3,056m (10,026ft)
K. Dewpoint Temp & Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Open in the southeast
M. Eye Shape & Diameter: Circular with a diameter of 18 nautical miles (21 statute miles)
N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Level: 700mb
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 1 nautical mile
Remarks Section:
Maximum Flight Level Wind: 88kts (~ 101.3mph) in the northeast quadrant at 7:29:40Z
Member Since: March 19, 2009 Posts: 0 Comments: 1421
Hey guys and lady

I'm really new at this! I love reading all the comments! It sounds like everyone knows what they r talking abt! Maybe one day I will know enough to add to the blog in a intelligent way! But all I do now is read and learn! But thank all of u for the info!

JMW
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The latest GFDL on 97L

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Most of the other models disagree with this


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While the GFDL want to bring Rina directly over South Florida as a strong system in 108 hours.

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The lastest HWRF run want to bring 97L over Cuba towards S Fl as a strong system in 126 hours.

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Quoting TampaSpin:


Because the cold front which was once thought to be very strong and come very far south is not going to do so not it appears.....that is the reason....The HIGH is not going to break down as much as first thought. I may be wrong of course but, from everything that i have looked at all day with the cold front......this is what i have seen. The BAM models are very good models for direction. When the BAMD which is far a very strong storm goes that far WEST the rest of the models usually follow suit.....we will see. Just my opinion.


Per yesterdays runs. But now models have recently deepened this trough.
Member Since: May 26, 2007 Posts: 47 Comments: 1287
Anyone think this will stay South of Cuba or come near the FLorida Keys?
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ATCF thinks 80 kts
000
WHXX01 KWBC 250636
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS NATIONAL HURRICANE CENTER MIAMI FL
0636 UTC TUE OCT 25 2011

DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.

ATLANTIC OBJECTIVE AIDS FOR

TROPICAL CYCLONE RINA (AL182011) 20111025 0600 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
111025 0600 111025 1800 111026 0600 111026 1800

LAT LON LAT LON LAT LON LAT LON
BAMS 17.3N 83.5W 17.2N 85.1W 17.2N 86.7W 17.4N 88.4W
BAMD 17.3N 83.5W 17.9N 84.9W 18.7N 86.3W 19.4N 87.5W
BAMM 17.3N 83.5W 17.7N 84.9W 18.1N 86.3W 18.6N 87.6W
LBAR 17.3N 83.5W 17.7N 84.4W 18.6N 85.7W 19.9N 87.0W
SHIP 80KTS 88KTS 92KTS 90KTS
DSHP 80KTS 88KTS 92KTS 90KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
111027 0600 111028 0600 111029 0600 111030 0600

LAT LON LAT LON LAT LON LAT LON
BAMS 17.7N 89.5W 18.3N 90.3W 16.6N 91.3W 14.6N 94.5W
BAMD 20.5N 88.7W 24.0N 89.3W 29.9N 79.7W 39.3N 53.9W
BAMM 19.3N 88.7W 20.8N 89.7W 20.0N 90.1W 18.5N 91.9W
LBAR 21.6N 87.8W 26.1N 85.8W 31.7N 75.7W .0N .0W
SHIP 85KTS 72KTS 55KTS 45KTS
DSHP 85KTS 58KTS 48KTS 39KTS

...INITIAL CONDITIONS...
LATCUR = 17.3N LONCUR = 83.5W DIRCUR = 290DEG SPDCUR = 3KT
LATM12 = 17.1N LONM12 = 83.0W DIRM12 = 293DEG SPDM12 = 3KT
LATM24 = 16.5N LONM24 = 82.2W
WNDCUR = 80KT RMAXWD = 10NM WNDM12 = 65KT
CENPRS = 976MB OUTPRS = 1012MB OUTRAD = 175NM SDEPTH = D
RD34NE = 60NM RD34SE = 60NM RD34SW = 75NM RD34NW = 100NM

$$
NNNN
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Nevermind, I found them...Swan Islands. Didn't realize Mitch passed over them at peak intensity.
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Just out of curiosity, what are the small islands just to the west-northwest of Rina's center? They're very small, and I can't seem to find a map that has them named. I imagine they're unpopulated, but I ask because they'll feel the brunt of Rina for a very long time.
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Quoting Twinkster:


That makes no sense. Cold fronts create weaknesses in highs and enable low pressure systems such as a hurricane to move more poleward. The cold front is strong right now however the flow is supposed to become more zonal as the week progresses and should result in a weak cold front that barely gets into south eastern United States this would result in what the GFS shows in 00z run in which Rina would get stuck in weak steering currents due to a high building in over the GOM once the trough lifts out and the high pressure centered over central america


No true. the flow is supposed to be northwesterly through the weekend into Monday.
Member Since: May 26, 2007 Posts: 47 Comments: 1287
Quoting JLPR2:


I'm impressed to see that wind reading being used considering how suspicious it looks.

Time: 06:00:30Z
Coordinates: 17.3N 83.6167W
Acft. Static Air Press: 700.3 mb (~ 20.68 inHg)
Acft. Geopotential Hgt: 2,940 meters (~ 9,646 feet)
Extrap. Sfc. Press: -
D-value: -
Flt. Lvl. Wind (30s): From 13° at 54 knots (From the NNE at ~ 62.1 mph)
Air Temp: 10.9°C* (~ 51.6°F*)
Dew Pt: -*
Peak (10s) Flt. Lvl. Wind: 60 knots (~ 69.0 mph)
SFMR Peak (10s) Sfc. Wind: 89 knots* (~ 102.3 mph*)
SFMR Rain Rate: 9 mm/hr* (~ 0.35 in/hr*)
(*) Denotes suspect data

Hurricane force winds are only about 10-15 NM from the center. They may have hit "Rina'a sweet spot".
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945. JLPR2
Quoting Bordonaro:


000
URNT12 KNHC 250627



I'm impressed to see that wind reading being used considering how suspicious it looks.

Time: 06:00:30Z
Coordinates: 17.3N 83.6167W
Acft. Static Air Press: 700.3 mb (~ 20.68 inHg)
Acft. Geopotential Hgt: 2,940 meters (~ 9,646 feet)
Extrap. Sfc. Press: -
D-value: -
Flt. Lvl. Wind (30s): From 13° at 54 knots (From the NNE at ~ 62.1 mph)
Air Temp: 10.9°C* (~ 51.6°F*)
Dew Pt: -*
Peak (10s) Flt. Lvl. Wind: 60 knots (~ 69.0 mph)
SFMR Peak (10s) Sfc. Wind: 89 knots* (~ 102.3 mph*)
SFMR Rain Rate: 9 mm/hr* (~ 0.35 in/hr*)
(*) Denotes suspect data
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89 kts~102 mph. Rina looks like a CAT 2 :)Would not surprise me to see a Special Advisory issued shortly.
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Quoting JLPR2:
Strongest winds found on the first pass:
Peak (10s) Flt. Lvl. Wind: 79 knots (~ 90.8 mph)
SFMR Peak (10s) Sfc. Wind: 85 knots (~ 97.7 mph)
SFMR Rain Rate: 26 mm/hr (~ 1.02 in/hr)

Minimum pressure 977mb.


000
URNT12 KNHC 250627
VORTEX DATA MESSAGE AL182011
A. 25/06:02:40Z
B. 17 deg 16 min N
083 deg 29 min W
C. 700 mb 2910 m
D. 89 kt
E. 283 deg 7 nm
F. 025 deg 79 kt
G. 291 deg 10 nm
H. 977 mb
I. 7 C / 3056 m
J. 17 C / 3038 m
K. NA / NA
L. OPEN SE
M. C20
N. 12345 / 7
O. 0.02 / 1 nm
P. AF304 0318A RINA OB 07
MAX OUTBOUND AND MAX FL WIND 84 KT SE QUAD 06:06:30Z
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942. JLPR2
Strongest non-suspect winds found on the first pass:
Peak (10s) Flt. Lvl. Wind: 79 knots (~ 90.8 mph)
SFMR Peak (10s) Sfc. Wind: 85 knots (~ 97.7 mph)
SFMR Rain Rate: 26 mm/hr (~ 1.02 in/hr)

Minimum pressure 977mb.
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Quoting cchsweatherman:
How can a model like the GFS be taken seriously into consideration when the model initializes a strengthening 985 mb hurricane as a 1008 mb low? Makes a big difference in the future motion of the storm.


The GFS analysis can not resolve pressure gradients like those that are found near the center of a hurricane. I don't know exactly what the operational GFS resolution is but probably a gradient of 10 mb in 40 km like you would find in a hurricane could not be represented as an initial condition.
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Recon measured 85 knot flight level winds in the SE quadrant.
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Quoting ProgressivePulse:
897. GTcooliebai 4:34 AM GMT on October 25, 2011

Edit 3a. Storms rotate "Counter Clockwise" around a common center. Rina would dive S as 97L approaches from the ESE.



The HWRF and GFDL seem to be the most accurate track wise(as Rina feels the force of the trough).
Member Since: May 26, 2007 Posts: 47 Comments: 1287
Quoting TropicalWeatherGrl88:
I honestly find it so ironic that all season long troughs have been picking up hurricanes. Now all of a sudden we are in October where there are more troughs, and this hurricane is suppose to be left behind because the trough will not dig down deep enough.... WEIRD??


Well now models are digging this trough deeper so Friday it'll be over South Florida and Saturday it should be gone(absorbed by the trough).
Member Since: May 26, 2007 Posts: 47 Comments: 1287
I think that when Rina hits all of that shear to her north she will end up looking like cole slaw.
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To Levi,
Thanks for your replies to my questions on the previous posts! You are the best! Once we get this mischief out of the way, I have a few more. BTW, hows does SWF look in your opinion as a potential landfall? Lots of us bloggers live here! Thanks, BKH
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Quoting SouthDadeFish:
00Z HWRF hooks Rina south like the 00Z GFS....

I truly not liking the HWRF for 97L puts iy right ontop of GCM (me)
Member Since: June 13, 2009 Posts: 2 Comments: 11843
00Z HWRF hooks Rina south like the 00Z GFS....
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Heading in.

3,210 meters
(~ 10,531 feet)
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Quoting Tazmanian:
good night



cat 1 storm now i may wake up too a cat 4 or 5


Not uncommon for October storms in the Western Caribbean.
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Quoting GTcooliebai:
Idk? If I had to venture a guess it's probably a feedback issue. I do know that Recon is suppose to be collecting some data later today to input into the models, so maybe it will catch on then.


I am interested to see if the Euro shows the same thing.
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Quoting TropicalWeatherGrl88:


It sure will be intersting to see how it plays out. Do you know why the GFS initialization has 1008 mb?
Idk? If I had to venture a guess it's probably a feedback issue. I do know that Recon is suppose to be collecting some data later today to input into the models, so maybe it will catch on then.
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The eye is starting to become apparent on IR imagery:



Notice the yellow colors (-80C) almost fully surrounding the eye. Also has that buzzsaw shape going on with the strong feeder band to the W and N. I'm very anxious to see what recon finds.
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I think she will either blow up and become cat 2-4 quick or she will die out. I dont know why, but I feel like there will be no middle, but who knows...
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good night



cat 1 storm now i may wake up too a cat 4 or 5
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Quoting GTcooliebai:
Yeah apparently that is what the GFS model is thinking, now I can't be sure if that is because the upper level winds will severely weaken this storm or the trough lifting out w/o taking Rina with it, or even an interaction with 97L? This is definitely one of the times when the track is a low-confidence one and we might not know until Rina makes landfall on the Yucatan.


It sure will be intersting to see how it plays out. Do you know why the GFS initialization has 1008 mb?
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Quoting TropicalWeatherGrl88:
I honestly find it so ironic that all season long troughs have been picking up hurricanes. Now all of a sudden we are in October where there are more troughs, and this hurricane is suppose to be left behind because the trough will not dig down deep enough.... WEIRD??
Yeah apparently that is what the GFS model is thinking, now I can't be sure if that is because the upper level winds will severely weaken this storm or the trough lifting out w/o taking Rina with it, or even an interaction with 97L? This is definitely one of the times when the track is a low-confidence one and we might not know until Rina makes landfall on the Yucatan.
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Quoting GTcooliebai:
Actually sunlinepr this is the steering you should use for a 70 knot Hurricane



Yap, thanks...
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Quoting stormwatcherCI:
According to what I heard the govt. didn't want the US to know how bad it was because they wanted to get tourism back up asap.

ok there was a british warship that was sent here circled the Island 3 time waiting for the Gov. to tell them to come in Gov. refused it dispite CNN already stating that Grand Cayman was litteray off of the map the US knew how bad it was they don't need the Gov. to tell them that but no look that was a stupid decision by our Gov. anyway I hope they learn they lession
Member Since: June 13, 2009 Posts: 2 Comments: 11843
Quoting cchsweatherman:
How can a model like the GFS be taken seriously into consideration when the model initializes a strengthening 985 mb hurricane as a 1008 mb low? Makes a big difference in the future motion of the storm.


I was wondering why it was doing that.
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I honestly find it so ironic that all season long troughs have been picking up hurricanes. Now all of a sudden we are in October where there are more troughs, and this hurricane is suppose to be left behind because the trough will not dig down deep enough.... WEIRD??
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M>110

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How can a model like the GFS be taken seriously into consideration when the model initializes a strengthening 985 mb hurricane as a 1008 mb low? Makes a big difference in the future motion of the storm.
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Quoting GTcooliebai:
Oh yeah so if Rina went south then 97L would move north and then comeback south while Rina went north?


Typically the interactions are short lived as there is usually a more dominant cyclone in which case the weaker cyclone orbits counter clockwise around the more dominant until it is absorbed.


In a case if they were of the same intensity then yes Rina dives south and Sean Heads N and the orbit would continue until a dominant cyclone took over. In this case, there is a lot of land & dry air in the way so it wouldn't take long to produce a dominant cyclone.
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Either the current wind shear maps are wrong, or Rina is a new breed of hurricanes to come! You cant have 20 to 25 mph wind shear over the LLC and have an intensifing hurricane.
Member Since: June 13, 2009 Posts: 0 Comments: 6757
Quoting sunlinepr:
Actually sunlinepr this is the steering you should use for a 70 knot Hurricane

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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