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Tropical Storm Erika Headed for the Lesser Antilles

By: Jeff Masters 3:13 PM GMT on August 25, 2015

Tropical storm watches are up for much of the northern Lesser Antilles Islands as Tropical Storm Erika speeds westwards at 20 mph. Erika formed in the waters a few hundred miles east of the northern Lesser Antilles Islands overnight, and is likely to take a west to west-northwest course over the next few days, a path that should concern residents of the Bahamas and the U.S. East Coast. However, Erika’s survival over the next few days is not a sure thing. Satellite loops on Tuesday morning showed that Erika was struggling, with the low-level center exposed to view and only a small and decreasing area of heavy thunderstorms, limited to the storm’s south side. Wind shear due to upper-level winds out of the northeast was moderate, 10 - 15 knots, and this shear was driving plenty of dry air on the north side of Erika into its core, disrupting the storm. Sea surface temperatures (SSTs) are favorable for development, though—near 27.5°C—and will warm to 28.5°C by Thursday.


Figure 1. Latest satellite image of Tropical Storm Erika.

Forecast for Erika
The 8 am EDT Tuesday run of the SHIPS model predicted that wind shear would remain in the moderate range through the remainder of the week. Steering currents for Erika are very similar to what Danny experienced, and the 8 pm EDT Monday (00Z Tuesday) run of the GFS and European models showed Erika taking a track into or just north of the northern Lesser Antilles Islands on Wednesday night, and into the Southeast Bahamas by Saturday. A trough of low pressure capable of turning Erika to the north will set up shop along the U.S. East Coast late this week, but it is uncertain at this time whether or not Erika will be strong enough to get picked up by this trough. If Erika manages to fight off the dry air and wind shear besetting it and grow into a strong tropical storm by Thursday, it would likely take a more northerly course and be a long-range threat to the U.S. East Coast, Bermuda, or Canada early next week. If Erika stays weak, it will track more to the south, and take a path close to Hispaniola and into the Bahamas by this weekend. A path close to Hispaniola would potentially disrupt a weak Erika and cause it to dissipate; this was the solution of both the 00Z and 06Z Tuesday morning runs of the GFS model. Two of our other top three models from last year for predicting hurricane tracks--the HWRF and UKMET models--showed Erika staying stronger and taking a more northerly track with their 00Z Tuesday runs; the European model was in between, and showed Erika coming very close to the Florida coast by Monday (Figure 2). I'm not ready to ring the alarm bells on this storm yet, as a bet against significant strengthening is usually called for during a strong El Niño season. Still, El Niño years do get major hurricanes--the big hurricane of the last strong El Niño year of 1997 was also named Erika, and peaked at 946 mb /125 mph winds (thanks go to wunderground member BaltimoreBrian for this reminder.) The models should do a better job with Erika in their Tuesday night runs, since they will have data from the Hurricane Hunters to chew on. The NOAA jet is in the air today releasing dropsondes in the vicinity of Erika to characterize the upper-air steering currents, and there will also be low-level penetrations of Erika this afternoon from the Air Force Hurricane Hunters.


Figure 2. The 00Z Tuesday (8 pm EDT Monday) runs of the European and GFS models had two very different predictions of the intensity of Erika for 8 am Monday August 31, 2015. The European model showed Erika as a strong tropical storm just off the coast of Florida (purple colors = winds of at least 58 mph), while the GFS model showed Erika merely as a strong tropical wave with no closed circulation. Image taken from our wundermap with the “Model Data” layer turned on.


Figure 3. Forecasts of the track of Tropical Storm Erika from the 00Z Tuesday (8 pm EDT Monday) run of the GFS model from the twenty members of the GFS Ensemble model. The GFS Ensemble takes the operational version of the GFS model and makes twenty different runs of it at lower resolution with slightly different initial conditions to generate an ensemble of possible forecasts. As we can see, there are a wide variety of possible solutions. The operational high-res version of the GFS (white line) shows Erika dissipating near Hispaniola.

Two long-range threats for Hawaii
While Tropical Depression Kilo is no longer a threat to Hawaii, the islands should keep an eye on two tropical systems to its east, in the waters of the Eastern Pacific to the southwest of Mexico: Tropical Depression Twelve-E, and Invest 96E. According to the 00Z Tuesday run of the GFS model, both systems could eventually pass within 500 miles of the Hawaiian Islands.

WUTV Takes Over The Weather Channel again at 6 pm EDT Tuesday
I had a great time last night discussing the tropics and the history of Weather Underground on the inaugural episode of the Weather Underground live cable TV on The Weather Channel (TWC). Hosted by TWC meteorologist Mike Bettes, the show will air weekdays from 6 - 8 pm Eastern time. Today’s will discuss Erika and the rest of the action in the tropics, and will feature a look at ten years ago today, when Hurricane Katrina hit Miami. Bob Henson will be on the show tonight to offer his view of that day. Check out #WUTV for updates.  

Wunderblogger Dr. Phil Klotzbach of Colorado State has an excellent post today on the The Record-Setting Northern Hemisphere Tropical Cyclone Season - Part I

There will be at least one more post today on Erika in this blog.

Jeff Masters

Hurricane

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

Quoting 488. VAbeachhurricanes:

Yeah, it would be better if Erika hit the moon where no one lives.


That would be Alice.... (let's see how many people get this reference)

Gro -All my nights are sleepless. Back working mids. You can sleep, I'll watch out for you.
Erika is like "Gimme back my core!"



She really is doing a good job rebuilding.
Quoting 501. Dakster:



That would be Alice.... (let's see how many people get this reference)

Gro -All my nights are sleepless. Back working mids. You can sleep, I'll watch out for you.


I do not get that reference.
Quoting 476. TeleConnectSnow:



I might be new to this site, but I have been on many other forums before. I am not claiming what I say is what will happen, but based off latest observations on Erika staying fairly south and some models shifting further south, those type of runs by the GFS and EURO seem to have the most legitimacy in my opinion.
There are no observations, at least not until the hurricane hunter data is integrated. You're confusing a lot of blog and twitter chatter with observations. Writing off two of the six major models while declaring two of the remaining six major models winners when we're at least six days out is premature. That's what I mean by no experience.
Quoting 502. FunnelVortex:

Erika is like "Gimme back my core!"



She really is doing a good job rebuilding.


Die-hard tropical cyclone. May actually survive.

Gotta go now, will try to be back later.
Quoting 480. scottsvb:



Go with the GFS and Euro.... rest overdo systems, especially the CMC,GFDL and HWRF after 72hrs


Scott- I'm not discounting those models. My question was simply for historical purposes.
Quoting 493. 62901IL:



I would not advise that. It may be sad when a system degenerates or something, but by no means does that mean you should no longer track hurricanes.
I'm just messing around lol. However, the lack of interesting things to track is quite the bummer.
Quoting 501. Dakster:



That would be Alice.... (let's see how many people get this reference)

Gro -All my nights are sleepless. Back working mids. You can sleep, I'll watch out for you.
"Right to da moon, Alice...". Can you imagine a show like that being made today?
Quoting 491. BahaHurican:

You betcha, since if forecasts pan out the storm'll be somewhere in the MICAL district on Saturday morning .... and imagine all the people who will be stuck in Miami this weekend ..... [raises eyebrows]


That's true I wasn't thinking about that, I guess there will be a lot of houses in Nassau that won't be battened up if it does head this way. Either that or everyone will be scrambling to get the last few seats on the Friday night flights!!!!!!!
Quoting 504. sar2401:

There are no observations, at least not until the hurricane hunter data is integrated. You're confusing a lot of blog and twitter chatter with observations. Writing off two of the six major models while declaring two of the remaining six major models winners when we're at least six days out is premature. That's what I mean by no experience.

I can clearly see it drifting more and more west, still moving fast. So it will have a very hard time not scraping most of the landmasses.
Larger image

Convection seems to be retaking Danny's remnant swirl

Quoting 478. NasBahMan:



You're right a Cat 2 in the Bahamas would do very little damage other than tree damage and power loss caused by the falling trees. If it was slow moving we would have some flooding but it doesn't appear that would be a problem with Erica.
True, but I have seen cat-2,s do cat-3 and 4 damage..Hurricane Ike being a great example.
Quoting 503. 62901IL:



I do not get that reference.


An old TV show. The Honeymooners. Main character always threatens to knock Alice to the moon...

Once the models finally have upper-air data plugged into them, we'll have a much better idea of what's to come. Where the GFS and ECMWF are currently showing degeneration, with the upper-air data, could very well change their tune. Conversely, same could be said in reverse for the bullish models.

We'll just have to wait and see, as this is obviously not a cut and dry intensity forecast.
Quoting 466. CitikatzSouthFL:

Infrared seems to show ex-Danny with better convection than Erika. Any chance he might come back to life (like Andrew) and cause some trouble...mabe in GOMEX? Just wondering.
Possible? Sure. Probable? Not so much.
Nothing wrong with keeping an eye on it, but I wouldn't stress.
518. FOREX
Mike's Weather Page ‏@tropicalupdate · 10m10 minutes ago
Afternoon EURO not very excited with Erika. This run follows GFS with similar path west of Florida as a weak... http://fb.me/3updvmcCj




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Quoting 506. nash36:



Scott- I'm not discounting those models. My question was simply for historical purposes.
Didn't the CMC pretty much nail 2013 Andrea when no other model did? That was right after the "upgrade", when a lot of us thought we had a really good one now. Since then, the CMC has gotten hardly any storm right. Figures...
Quoting 492. win1gamegiantsplease:

OK, now that's a steady rain. Recant that last local update lol


Giants where are you? Im near airport and its a frog strangler here and booming
Time: 19:02:00Z
Coordinates: 16.300N 53.233W
Acft. Static Air Press: 843.7 mb
Acft. Geopotential Hgt: 1,561 m
Extrap. Sfc. Press: 1009.4 mb (29.81 inHg)
Flt. Lvl. Wind (30s): From 59° at 31 kts (From the ENE at 35.7 mph)
Air Temp: 17.2°C (63.0°F)
Dew Pt: 10.5°C (50.9°F)
Peak (10s) Flt. Lvl. Wind: 31 kts (35.7 mph)
SFMR Peak (10s) Sfc. Wind: 21 kts (24.2 mph)
SFMR Rain Rate: 1 mm/hr (0.04 in/hr)
Convection is already beginning to wane on the burst it just had, hope it improves more.
523. FOREX
12Z Euro has TD in East Gulf, 00Z had hurricane north of Bahamas next Tuesday. Quite a difference! ...Chris
Quoting 503. 62901IL:



I do not get that reference.


Honeymooners I believe
Erika is spinning up an incredibly large area of the atmosphere. I know this was mentioned last night, but she is about the size of Florida right now.


Quoting 393. Grothar:

Anyone remember what the name of this little thing was?




Blobucus Tryashemightus?
Quoting 476. TeleConnectSnow:



I might be new to this site, but I have been on many other forums before. I am not claiming what I say is what will happen, but based off latest observations on Erika staying fairly south and some models shifting further south, those type of runs by the GFS and EURO seem to have the most legitimacy in my opinion.
Good answer.

As usual, the named storm will be the judge [something we like to forget in here].


this tropical wave did not die out yet on land!!
And Danny was a Major Hurricane did the GFS or Euro predict that? Just shows you how fickle intensity can be.
Quoting 512. hydrus:

True, but I have seen cat-2,s do cat-3 and 4 damage..Hurricane Ike being a great example.


Over the last twenty five years of hurricanes in the Bahamas the vast majority of damage to structures have been from flooding either from inudation from the sea as in Jeanne and France, or the rain as in Michelle. The only storms that caused serious property damage from wind were Andrew and Floyd, and even then the damage was not what you would expect from a Cat 5 and Cat 4 storm.
Quoting 490. MiamiHurricanes09:

If Erika degenerates before reaching the Antilles then I give up on tracking tropical cyclones.


seems silly to do that. you've got like 5 other ocean basins to choose from!
Quoting 510. TeleConnectSnow:


I can clearly see it drifting more and more west, still moving fast. So it will have a very hard time not scraping most of the landmasses.
That assumes no slow down in forward speed, and that the weakness already present to the north doesn't affect the storm soon, causing a poleward turn. Either of those will decrease landmass interaction. Lots of things can happen in five days.
Quoting 529. sporteguy03:

And Danny was a Major Hurricane did the GFS or Euro predict that? Just shows you how fickle intensity can be.

Just because the previous system became a MH, doesn't mean Erika will, although it looks to have better conditions, so who knows.
Well...we know the drill.
Recon getting nearer to Erika's COC. Pressure is still around 1007mb and winds are primarily under 25kts thus far though.
Quoting 463. blueyedbiker:

To the Florida Casters, Just remember if the models are pointing to you 5 or 6 days out then your probably in the clear lol


Hi Blueyedbiker, I don't know you because I am not around much anymore, but I have always said the same thing, if you are in the cone 5 or 6 days out, you are probably going to be safe.... not always but as a general rule.

HI everyone, lurking here. I did check when I got home and could not believe the blob that was Danny. That storm may not be ready to exit yet. Not sure what is going on with Erika yet, still will just watch and wait and lurk. We have not even had a real threat in 10 years here in SE Fla (Ft Lauderdale area). But my house has always been prepared. After 2004/2005 even have upgraded doors, garage door, and have accordion shutters which takes 15 mins to close and a generator hubby cranks up every 6 months or so just to make sure it still works.........of course, have not needed to use them since we bought them!

carry on!
For tomorrow,

Plan of the Day


000
NOUS42 KNHC 251457
REPRPD
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1100 AM EDT TUE 25 AUGUST 2015
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 26/1100Z TO 27/1100Z AUGUST 2015
TCPOD NUMBER.....15-091

I. ATLANTIC REQUIREMENTS
1. TROPICAL STORM ERIKA
FLIGHT ONE -- TEAL 75 FLIGHT TWO -- TEAL 73
A. 26/2330Z A. 27/1130Z,1730Z
B. AFXXX 0305A ERIKA B. AFXXX 0405A ERIKA
C. 26/2230Z C. 27/1100Z
D. 17.4N 59.5W D. 18.0N 62.5W
E. 26/2300Z TO 27/0200Z E. 27/1115Z TO 27/1730Z
F. SFC TO 15,000FT F. SFC TO 15,000FT

2. OUTLOOK FOR SUCCEEDING DAY: CONTINUE 6-HRLY FIXES.
POSSIBLE G-IV SYNOPTIC SURVEILLANCE MISSION FOR 28/0000Z.
3. REMARKS:
A. NOAA P-3 RESEARCH MISSIONS AT 26/1800Z AND 27/0600Z
WILL PROVIDE ERIKA FIXES.
B. NOAA'S G-IV WILL FLY A RESEARCH MISSION AROUND ERIKA
AT 26/1400Z.
C. NASA'S GLOBAL HAWK WILL DEPART WALLOPS AT 26/1100Z FOR A
24 HR MISSION OVER ERIKA. FLIGHT LEVELS 55,000-63,000FT.
POSSIBLE 80 DROPSONDE RELEASES.

II. PACIFIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. SUCCEEDING DAY OUTLOOK.....NEGATIVE.

$$
JWP
Did I mention I received nearly 9.5" of rain for the week last week?.......see how calm we are in TX when it rains.............. no hype, no drama, just real.
Time: 19:12:00Z
Coordinates: 15.867N 52.783W
Acft. Static Air Press: 844.0 mb
Acft. Geopotential Hgt: 1,541 m
Extrap. Sfc. Press: 1007.5 mb (29.75 inHg)
Flt. Lvl. Wind (30s): From 50° at 20 kts (From the NE at 23.0 mph)
Air Temp: 18.1°C (64.6°F)
Dew Pt: 11.1°C (52.0°F)
Peak (10s) Flt. Lvl. Wind: 20 kts (23.0 mph)
SFMR Peak (10s) Sfc. Wind: 22 kts* (25.3 mph*)
SFMR Rain Rate: 1 mm/hr* (0.04 in/hr*)
FL is covered as models shifted west again due to a weaker storm. Could be the NOAA data is already in the models.




Quoting 483. scottsvb:



Are you smoking something? You're 100% Fail on this statement.


The ever charming Scott..I was going to write up a reply back but I thought you ain't worth the ban and thats saying a lot from someone who is ban on a regular basis..

I was mistaken with respect to the Euro being in the same camp and the NAM but the NHC went with all three models, Euro, Navgem and UKMET for Cristobal..

In contrast, the ECMWF, UKMET,
and NAVGEM models keep Cristobal as a deeper, stronger, and more
vertically coherent cyclone, moving the system only slowly
north-northwestward or northwestward for the next 72 hours or so as
a strong mid-latitude trough over the Carolinas lifts out to the
northeast.


More weight has been placed the on
the ECMWF-UKMET-NAVGEM solutions, and the official forecast track
remains near the left side of the guidance envelope.


i do not like this at all!!
Quoting 483. scottsvb:



Are you smoking something? You're 100% Fail on this statement.
Proof?

StormTrackerScott we have an emergency over the NWS site, as insane rains are falling!!!!


       Rained here a bit. Hey Joe, you getting any of this??
Quoting 540. RitaEvac:

Did I mention I received nearly 9.5" of rain for the week last week?.......see how calm we are in TX when it rains.............. no hype, no drama, just real.


no drama-caster'
Quoting 535. TeleConnectSnow:


Just because the previous system became a MH, doesn't mean Erika will, although it looks to have better conditions, so who knows.

Was not my point, my point was the Euro and GFS did not see that nor did the NHC, it is an observation that the weather does not always go according to the models. With all that being said the forecasters at the NHC are doing the best job they can and I am grateful they are there.


wow!!!!!! East Atlantic
Quoting 534. Patrap:

Someone had a good question. Why would the BAMM-D(Deep storm) show Ericka moving more west and south than BAMM-S(Shallow storm)? Shouldn't a deeper storm fell a weakness north of it more? Anyone.
Quoting 530. NasBahMan:



Over the last twenty five years of hurricanes in the Bahamas the vast majority of damage to structures have been from flooding either from inudation from the sea as in Jeanne and France, or the rain as in Michelle. The only storms that caused serious property damage from wind were Andrew and Floyd, and even then the damage was not what you would expect from a Cat 5 and Cat 4 storm.
Even storms of lower intensity can cause problems and loss of life here, as in Noel, which was only a tropical storm at the time, but which brought extensive flooding to the central Bahamas and the loss of one life. We're not saying wind damage doesn't occur, just that storm surge and freshwater flooding damage are more likely.
Assuming Erica isn't pulled to the north as quickly as earlier predicted would there be any kind of ridge or something to keep her going west into the central GOM and towards TX/LA area? Thanks, I know it's so far out anything could be possible just wondering what the group thoughts might be for possibilities
Convection is already beginning to wane on the burst next to the center
good afternoon all

I have not been on here in many years, but figure I would come back to look at the opinions of everyone on this Tropical storm
Pressue is 1005mb. Erika may be weaker than we thought.

192130 1532N 05219W 8435 01535 0053 +192 +111 231009 010 028 000 00
12z NCEP Ensembles..

AN OVERVIEW OF NHC PREDICTION MODELS

Bernard N. Meisner
Scientific Services Division
National Weather Service Southern Region

Introduction

Meteorologists at the National Hurricane Center (NHC) have a variety of prediction models available to provide guidance for their forecasts of tropical cyclone tracks and intensity. The intent of this paper is to provide a brief overview of each of the models. Forecasters may find this information helpful when considering NHC discussions which mention the performance of individual models. A primary reference is provided after the summary of each model for readers who desire more information. NOTE: All thumbnail graphics in this Web document are linked to larger version of the graphics. Just click the thumbnail to view the larger version.

As noted by Neumann (1979), models for the prediction of tropical cyclone motion and intensity may be classified as either statistical or dynamical. Statistical models rely on what has happened-the climatology of past storms, for example. Dynamical models can be classified as either barotropic or baroclinic. Statistical-dynamical models are an intermediate class that incorporate numerically forecast data into a statistical prediction framework, similar to the Model Output Statistics used to provide guidance for specific parameters such as temperature and probability of precipitation.

BAM - The Beta and Advection Model

The Beta and Advection Model is a baroclinic-dynamical track prediction model. It produces a forecast track by following a trajectory in the vertically averaged horizontal wind starting at the current storm location out to 120 hours. The trajectory is corrected to account for the variation of the Coriolis force with latitude, the so-called Beta effect. (Beta is the Greek letter frequently used in meteorological equations to represent the change in the Coriolis parameter with latitude.)

The figure shows how the conservation of absolute vorticity results in the formation of anticyclonic relative vorticity in the northeast quadrant of the storm, and the formation of cyclonic relative vorticity in the southwest quadrant of the storm: Diagram of absolute vorticity advection and relative vorticity formation in the vicinity of a tropical cyclone.. The result adds a component of motion to the northwest to the storm's trajectory.



Three versions of the BAM model are run with shallow (850-700 mb), medium (850-400 mb), and deep (850-200 mb) layers. All three versions of the model are run operationally four times per day.

Reference: Marks, D. G., 1992: The beta and advection model for hurricane track forecasting. NOAA Tech. Memo. NWS NMC- 70, 89 pp.
Quoting 554. lsu60driver:

Assuming Erica isn't pulled to the north as quickly as earlier predicted would there be any kind of ridge or something to keep her going west into the central GOM and towards TX/LA area? Thanks, I know it's so far out anything could be possible just wondering what the group thoughts might be for possibilities


Right Now I Think Anything Is Possible. Just Be Prepared
Quoting 557. MiamiHurricanes09:

Pressue is 1005mb. Erika may be weaker than we thought.

192130 1532N 05219W 8435 01535 0053 +192 +111 231009 010 028 000 00
maybe a open wave now
Quoting 557. MiamiHurricanes09:

Pressue is 1005mb. Erika may be weaker than we thought.

192130 1532N 05219W 8435 01535 0053 +192 +111 231009 010 028 000 00

They just got there, give it time
TS Erika

Rainbow Loop

Quoting 561. hurricanes2018:

maybe a open wave now
No, there's west winds to support a closed circulation, albeit broad.
Quoting 558. ncstorm:

12z NCEP Ensembles..




FL, GA, SC and NC.
Erika so far looks weaker than most us of thought, however, just looking at the view on the floater its not surprising
Quoting 556. mahep1911:

good afternoon all

I have not been on here in many years, but figure I would come back to look at the opinions of everyone on this Tropical storm
Cool! Welcome back. The blog is likely to be increasingly busy this week ....
Erika is fighting to try and cover up the LLC to the N of the main convective envelope. Large system. DMAX coming. Tonight presents an opportunity for Erika to pull it together for the long haul.
Quoting 562. Hurricanes101:

As far as pressure is concerned, it's above the NHC's estimate. Let's see how the winds are doing as they investigate.
Quoting 566. nash36:



FL, GA, SC and NC.


K8eCane Doesnt Like This
Quoting 559. Patrap:

AN OVERVIEW OF NHC PREDICTION MODELS

Bernard N. Meisner
Scientific Services Division
National Weather Service Southern Region

Introduction

Meteorologists at the National Hurricane Center (NHC) have a variety of prediction models available to provide guidance for their forecasts of tropical cyclone tracks and intensity. The intent of this paper is to provide a brief overview of each of the models. Forecasters may find this information helpful when considering NHC discussions which mention the performance of individual models. A primary reference is provided after the summary of each model for readers who desire more information. NOTE: All thumbnail graphics in this Web document are linked to larger version of the graphics. Just click the thumbnail to view the larger version.

As noted by Neumann (1979), models for the prediction of tropical cyclone motion and intensity may be classified as either statistical or dynamical. Statistical models rely on what has happened-the climatology of past storms, for example. Dynamical models can be classified as either barotropic or baroclinic. Statistical-dynamical models are an intermediate class that incorporate numerically forecast data into a statistical prediction framework, similar to the Model Output Statistics used to provide guidance for specific parameters such as temperature and probability of precipitation.

BAM - The Beta and Advection Model

The Beta and Advection Model is a baroclinic-dynamical track prediction model. It produces a forecast track by following a trajectory in the vertically averaged horizontal wind starting at the current storm location out to 120 hours. The trajectory is corrected to account for the variation of the Coriolis force with latitude, the so-called Beta effect. (Beta is the Greek letter frequently used in meteorological equations to represent the change in the Coriolis parameter with latitude.)

The figure shows how the conservation of absolute vorticity results in the formation of anticyclonic relative vorticity in the northeast quadrant of the storm, and the formation of cyclonic relative vorticity in the southwest quadrant of the storm: Diagram of absolute vorticity advection and relative vorticity formation in the vicinity of a tropical cyclone.. The result adds a component of motion to the northwest to the storm's trajectory.



Three versions of the BAM model are run with shallow (850-700 mb), medium (850-400 mb), and deep (850-200 mb) layers. All three versions of the model are run operationally four times per day.

Reference: Marks, D. G., 1992: The beta and advection model for hurricane track forecasting. NOAA Tech. Memo. NWS NMC- 70, 89 pp.
So BAMM models have nothing to do with storm strength?
574. FOREX
Quoting 569. nash36:

Erika is fighting to try and cover up the LLC to the N of the main convective envelope. Large system. DMAX coming. Tonight presents an opportunity for Erika to pull it together for the long haul.


Finally some common sense. Thank you.
1005/37 so far
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
324 PM EDT TUE AUG 25 2015

.LONG TERM (WEDNESDAY NIGHT-TUESDAY)...
A TROUGH AT THE SURFACE AND ALOFT WILL BE IN PLACE ACROSS THE
REGION THROUGH FRIDAY KEEPING HIGHER RAIN CHANCES WITH DEEP
MOISTURE IN PLACE. HIGH PRESSURE WILL THEN RIDGE INTO THE AREA
FROM THE NE FOR THE WEEKEND WITH EASTERLY FLOW RETURNING. THIS
WILL BRING SCATTERED TO NUMEROUS AFTERNOON THUNDERSTORMS WITH THE
SEA BREEZE. MONDAY AND TUESDAY WILL BE MONITORED AS ERIKA MAY BE
INFLUENCING THE AREA. MODELS ARE VERY DIFFERENT IN THEIR
SOLUTIONS...THE GFS WITH JUST A WEAK TROUGH ACROSS THE REGION AND
THE ECMWF TRACKING IT OVER THE GULF STREAM UP THE EAST FL COAST.
FOR NOW...HAVE KEPT THE FORECAST CLOSER TO CLIMO UNTIL MORE
CONSISTENCY COMES IN. TEMPERATURES WILL BE IN THE 70S TO AROUND 80
FOR LOWS AND IN THE UPPER 80S TO LOWER 90S FOR HIGHS EACH DAY.
Link
Quoting 570. MiamiHurricanes09:

As far as pressure is concerned, it's above the NHC's estimate. Let's see how the winds are doing as they investigate.


That pressure was with winds of 19 knots, not the center
Quoting 512. hydrus:

True, but I have seen cat-2,s do cat-3 and 4 damage..Hurricane Ike being a great example.


Irene devastated Long Island Bahamas in 2011. It was a cat 3.
still bunch of time for the models to get some bend to them . might be a good time to fuel up.
Quoting 566. nash36:



FL, GA, SC and NC.
This is as wide open as Danny .... all depends on what happens w/ the trough.
I think Erika's COC is relocating to the south under the main convection. The winds at the buoy in front are from the north east.
Predicting strength is a guesstimate right now. The 1016 line around the Bermuda High is what has my attention.
I will be interested to see what the 8 pm runs look like.I believe that is when the information will have been put into the models from today's missions. the storm has gotten a lot more convection then this morning. I remember when I started on here I did not have all the knowledge I do now, and the computer programs like GR2 Analyst and GR3. I do remember when the blog was going crazy be for each advisory went through a ton of F5 keys lol
Quoting 530. NasBahMan:



Over the last twenty five years of hurricanes in the Bahamas the vast majority of damage to structures have been from flooding either from inudation from the sea as in Jeanne and France, or the rain as in Michelle. The only storms that caused serious property damage from wind were Andrew and Floyd, and even then the damage was not what you would expect from a Cat 5 and Cat 4 storm.
The Bahamas are sparsely populated, excluding the largest islands near the coast of Florida. Structures there are likely reinforced due to the fact they are squarely in the hurricane belt. Suffice to say, a cat-2 for folks there may not seem like much to many living there, but I have been through a cat-2 myself, and prefer not to experience it again..
We are all guessing where ths storm is headed. We need to wait until we have more information from recon. aand the models will actually give us a better IDEA of where it MIGHT go. Mother nature has it own rules and we will never know what they are.
Quoting 580. BahaHurican:

This is as wide open as Danny .... all depends on what happens w/ the trough.


Yep. And, what layer Erika is in. How deep does she ultimately become?? We'll see.
Honestly, with the steering pattern shown on the EURO/GFS, I don't see how it goes up the eastern seaboard...The only chance I see for it to turn north would be over the eastern Gulf as a retrograding upper-level trough opens up the meridional (south-to-north) flow. Retrograding upper-level low also makes me very nervous. Plenty of anticyclonic flow over the eastern Gulf/southwestern Atlantic through days 5-7.
Quoting 577. Hurricanes101:



That pressure was with winds of 19 knots, not the center
I think you're going by the SFMR instrument. Flight level winds have been below 10kts with the presence of west winds. They just went back and the pressure is 1005mb.

192700 1531N 05222W 8436 01534 0050 +197 +094 237001 002 029 000 00
Quoting 572. unknowncomic:

So BAMM models have nothing to do with storm strength?
The BAM models have never had anything to do with intensity. They have always been track models. Anytime you see a BAM model on an intensity chart, it's a mathematical perversion of the original model.
Quoting 569. nash36:

Erika is fighting to try and cover up the LLC to the N of the main convective envelope. Large system. DMAX coming. Tonight presents an opportunity for Erika to pull it together for the long haul.
or fail into a blog meltdown


the center still got no rain and t.storm with it the rain is south of the center!!


6 minutes old
Quoting 590. KEEPEROFTHEGATE:

or fail into a blog meltdown


Indeed. If Erika dies, this place will be apoplectic. Virtual Xanax will be flying around.
can someone please explain to erika that the MDR is dead....and as such she must cease and desist immediately!!!....



there you go folks....the eastern seaboard is safe now
Quoting 593. nash36:



Indeed. If Erika dies, this place will be apoplectic. Virtual Xanax will be flying around.
more so cause we are just getting over MH danny
Quoting 593. nash36:



Indeed. If Erika dies, this place will be apoplectic. Virtual Xanax will be flying around.


I HAVE THEM!
RECON find a weak broad LLCOC it's also possible it may not be fully closed another thing it seems winds are weaker
Quoting 566. nash36:



FL, GA, SC and NC.
Wait...there's 1.5 lines in Alabama too...plus one in Virginia...and there's another one headed for Texas...

Seriously, how does one get useful information from a chart like that?
if I am not mistaken I would say llc is booking it nw leaving convection behind have too see next couple of hrs seems
No doubt, you guys cannot deny that Erika is weakening and kinda falling apart. It could still get going, but right now it doesn't really look all that good.
Also the lowest pressure found 1005mb
Higher than the 1003mb that NHC states
Quoting 592. KEEPEROFTHEGATE:



6 minutes old

That doesn't look like a dead storm. It does look like a storm that needs to head more north to avoid a collision.
To my untrained eye if looks as if the shear is ripping her apart. There may be nothing left if this continues. Former Danny looks better at the moment to me.
Quoting 598. Patrap:




Strange how under 10 knots and over 90 knots are almost the same color. Still not used to it by now, takes me three seconds to reapply common sense to my brain.
Back to RIP LOL
Yall crack me up
Quoting 603. unknowncomic:

That doesn't look like a dead storm. It does look like a storm that needs to head more north to avoid a collision.
its not dead but there is a convective displacement occurring at the moment how it plays out we have too wait and see
Quoting 598. Patrap:




Barely TS strength
Quoting 587. louisianaboy444:

Honestly, with the steering pattern shown on the EURO/GFS, I don't see how it goes up the eastern seaboard...The only chance I see for it to turn north would be over the eastern Gulf as a retrograding upper-level trough opens up the meridional (south-to-north) flow. Retrograding upper-level low also makes me very nervous. Plenty of anticyclonic flow over the eastern Gulf/southwestern Atlantic through days 5-7.


Stop making so much since...lol
Quoting 547. RitaEvac:

StormTrackerScott we have an emergency over the NWS site, as insane rains are falling!!!!




Nice Rita as you guys were dry the last 2 months so this is welcomed right.
Quoting 587. louisianaboy444:

Honestly, with the steering pattern shown on the EURO/GFS, I don't see how it goes up the eastern seaboard...The only chance I see for it to turn north would be over the eastern Gulf as a retrograding upper-level trough opens up the meridional (south-to-north) flow. Retrograding upper-level low also makes me very nervous. Plenty of anticyclonic flow over the eastern Gulf/southwestern Atlantic through days 5-7.


It could do much of it's strengthening it'll ever have in that time period. Let's see if that prediction remains true in a few days.
USAFR RECON low level mission flying at 5,000ft level
NOAA RECON flying low level mission at 10,000ft level
NOAA RECON flying upper level mission at 45,000ft level

Here we go...
Ok so when Danny more or less died I stopped monitoring but now I see Erika and I hear she might bit or come very close to where I live... Please tell me it aint so... I live in SE Florida between Miami and FT Lauderdale about 1 mile from the coast.
Going to be an interesting few days.

Does this mean the high is stronger? Educate me, please.
Quoting 582. cajunkid:

Predicting strength is a guesstimate right now. The 1016 line around the Bermuda High is what has my attention.
Quoting 578. georgevandenberghe:



Irene devastated Long Island Bahamas in 2011. It was a cat 3.


Devastated is a strong word, there was a lot of damage to crops, trees and utility poles, building damage was less severe, some roof damage and heavier damage to very old or poorly constructed buildings. Most of the modern buildings, and older properly constructed buildings, even the older wooden homes, suffered little to no damage other than some loss of shingles.

Quoting 613. opal92nwf:

Here we go...



Can we not use that stupid rainbow frames, it makes it look so much better..convection is waning and the center looks to be leaving it behind. Not good man.
as per cimiss 2 out of 3 levels are in line





Quoting 615. StormTrackerScott:

Going to be an interesting few days.



You do realize all those that hit FL are like 1008 MB or weaker right? I just checked the ensembles and none of thoe who hurricanes, only the ones off the coast and OTS
Tropical Storm IGNACIO
As of 18:00 UTC Aug 25, 2015:

Location: 13.1°N 132.6°W
Maximum Winds: 35 kt Gusts: 45 kt
Minimum Central Pressure: 1004 mb
Environmental Pressure: 1010 mb
Radius of Circulation: 200 NM
Radius of Maximum Wind: 40 NM
Eye Diameter: N/A




624. A4Guy
Quoting 613. opal92nwf:

Here we go...



Here we go what? Convection was building...but seems to be waning again. Not covering the center, and not any kind of spiral banding evident. Long way to go to be "well organized."
JeffMasters has created a new entry.
How can some go on here and say RIP. Erika looks decent given her environment.

Quoting 624. A4Guy:



Here we go what? Convection was building...but seems to be waning again. Not covering the center, and not any kind of spiral banding evident. Long way to go to be "well organized."


None of this was really unexpected. It was expected that Erika would, at best, maintain its current intensity, as the system fought the same crap that chewed Danny up. It has to survive this before any appreciable intensification will take hold. Doesn't mean it will. Doesn't mean it won't. It need to take advantage of DMAX tonight, tighten up and slow down.
SFMR instrument may be showing 40+kt winds but at flight-level they haven't exceeded 20kts. Seems to be faulty.
Quoting 587. louisianaboy444:

Honestly, with the steering pattern shown on the EURO/GFS, I don't see how it goes up the eastern seaboard...The only chance I see for it to turn north would be over the eastern Gulf as a retrograding upper-level trough opens up the meridional (south-to-north) flow. Retrograding upper-level low also makes me very nervous. Plenty of anticyclonic flow over the eastern Gulf/southwestern Atlantic through days 5-7.


For you new guys, laboy444 is an actual working MET and we're lucky to have him.
Quoting 551. hurricanes2018:



wow!!!!!! East Atlantic
That wave about to come out of Africa might become something later on. Not sure if models are developing it.
dat wave comin out of africa tho
bomb

Quoting 551. hurricanes2018:



wow!!!!!! East Atlantic
Okay, I have lurked here for a few years. I am an idiot, more or less, when it comes to forecasting weather (which makes me at least the equivalelnt of most TV weathermen). I have learned far more in these past few years than I could ever imagine from reading intelligent comments and analysis. Since Danny started there have been an abundance of comments which are simply contradictory to the plain evidence you can see in satelite/IR/Dvorak... images, actual data from recon, solid analysis from real experts at NHC and from some truly gifted and experience people on this blog. All those comments do is slow down the Blog and irritate people.

In the last hour there have been many comments that Erika is an open way, being torn apart by shear... The image posted by KEEPEROFTHEGATE show a weak TS that is moving a large amount of atmosphere around it. It is doing exactly what the models (when taken as a whole) have indicated it would do. Why continue to post little bits of inflamatory trash that add nothing to the Blog?
Quoting 616. SecretStormNerd:

Does this mean the high is stronger? Educate me, please.



No, just looking at the forecast maps. Seems that's the steering layer for most storms. (From a novice point of view)
There are plenty pros on here that could educate you. I'm not qualified.
Quoting 618. TeleConnectSnow:



Can we not use that stupid rainbow frames, it makes it look so much better..convection is waning and the center looks to be leaving it behind. Not good man.
I'll agree with you on that. Although the idea seems to upset a few here, the rainbow view was developed specifically because TV weather forecasters complained to the NHC that their satellite views were too "boring". The forecasters that created the view made sure it was no longer boring. In the process, they also made it deceiving. Convection always looks more intense and widespread on a rainbow view than any other.
Quoting 584. hydrus:

The Bahamas are sparsely populated, excluding the largest islands near the coast of Florida. Structures there are likely reinforced due to the fact they are squarely in the hurricane belt. Suffice to say, a cat-2 for folks there may not seem like much to many living there, but I have been through a cat-2 myself, and prefer not to experience it again..


Your right in that the majority of our structures are well constructed as we have a pretty strong building code so if you build to code you have little to worry about in storms with winds below 125 mph. I also agree with you after going through many hurricanes over the years that if you ever go through a bad one you don't look forward to ever going through another one. I have been in major storms with no damage to the building I was in but it can be terrifying as it sounds like the building can come down around you at any moment. It is obvious that the people that comment hoping to get a hurricane where they live have never experienced one. Fortunately for anyone living in the US you have the option to get out of the way, here in the islands that option doesn't exist so we have to prepare to ride it out no matter how strong the storm will be. For those of you that have the ability to get out of the way I would strongly recommend you do so.
Quoting 534. Patrap:



Everyone Remember, that the models don't start bumping up intensity for another 36 Hours, so technically, its not weakening, its just staying as a weak TS and then going to strength.
A stronger Erika will tend to pull north and a weaker storm will veer west.

We have a few days for the models to resolve this it seems.
Quoting 636. NasBahMan:



Your right in that the majority of our structures are well constructed as we have a pretty strong building code so if you build to code you have little to worry about in storms with winds below 125 mph. I also agree with you after going through many hurricanes over the years that if you ever go through a bad one you don't look forward to ever going through another one. I have been in major storms with no damage to the building I was in but it can be terrifying as it sounds like the building can come down around you at any moment. It is obvious that the people that comment hoping to get a hurricane where they live have never experienced one. Fortunately for anyone living in the US you have the option to get out of the way, here in the islands that option doesn't exist so we have to prepare to ride it out no matter how strong the storm will be. For those of you that have the ability to get out of the way I would strongly recommend you do so.

We were told Andrew was going to turn north before it came ashore and hit the Fort Lauderdale to West Palm Beach area. So we did not get out of the way. But that was a prediction made over 20 years ago.
640. IKE
Keeping an eye on Erika here in the Florida panhandle. Something to follow. Hey to all bloggers.
Quoting 636. NasBahMan:



Your right in that the majority of our structures are well constructed as we have a pretty strong building code so if you build to code you have little to worry about in storms with winds below 125 mph. I also agree with you after going through many hurricanes over the years that if you ever go through a bad one you don't look forward to ever going through another one. I have been in major storms with no damage to the building I was in but it can be terrifying as it sounds like the building can come down around you at any moment. It is obvious that the people that comment hoping to get a hurricane where they live have never experienced one. Fortunately for anyone living in the US you have the option to get out of the way, here in the islands that option doesn't exist so we have to prepare to ride it out no matter how strong the storm will be. For those of you that have the ability to get out of the way I would strongly recommend you do so.
Charley was the worst I have seen wind wise. Gusts were recorded around 170 mph. Jeanne actually was the worst in the respect that it lasted for 15 hours. The blue tarp on our house was ripped to shreds ( damage from Charley ). The flooding absolutely ruined the few things we salvaged from the previous storms ( Francis did not help matters ).The power out, heat, standing water, and trees spattered all over the place made for a rough and difficult time for many...My parents moved to Tennessee
Quoting 633. CReed90:

Okay, I have lurked here for a few years. I am an idiot, more or less, when it comes to forecasting weather (which makes me at least the equivalelnt of most TV weathermen). I have learned far more in these past few years than I could ever imagine from reading intelligent comments and analysis. Since Danny started there have been an abundance of comments which are simply contradictory to the plain evidence you can see in satelite/IR/Dvorak... images, actual data from recon, solid analysis from real experts at NHC and from some truly gifted and experience people on this blog. All those comments do is slow down the Blog and irritate people.

In the last hour there have been many comments that Erika is an open way, being torn apart by shear... The image posted by KEEPEROFTHEGATE show a weak TS that is moving a large amount of atmosphere around it. It is doing exactly what the models (when taken as a whole) have indicated it would do. Why continue to post little bits of inflamatory trash that add nothing to the Blog?
Greetings Creed..If you lurked as long as you say, the inflammatory trash is just an unfortunate part of the blog. It may help if you bring acceptance to it, rather than grate your nerve. The blog is a great asset to any person that needs access to weather and its forecasting.
Quoting 617. NasBahMan:



Devastated is a strong word, there was a lot of damage to crops, trees and utility poles, building damage was less severe, some roof damage and heavier damage to very old or poorly constructed buildings. Most of the modern buildings, and older properly constructed buildings, even the older wooden homes, suffered little to no damage other than some loss of shingles.




My friends at Stella Maris told me it was a lot worse than that at their location


erika pullin northwest
Moved to New Blog.
A really big big wave is about to exit Africa.Very impressive one.
Quoting 122. tutanka:



im sorry, but what does culture have to do with whether or not he believes in climate change and how on earth did the conversation end up there??

Standard moral dilemma: https://en.wikipedia.org/wiki/Trolley_problem
Link
French Radar E Carib
Erika still moving W no WNW at this time

NOAA is on the way but likely no good they would be flying 10,000ft
We need another USAFR recon they would fly 5,000ft

Now that Erika is naked

Unless NOAA decides to drop current recon down to 5,000ft or less
Quoting 649. wunderkidcayman:

Erika still moving W no WNW at this time

NOAA is on the way but likely no good they would be flying 10,000ft
We need another USAFR recon they would fly 5,000ft

Now that Erika is naked

Unless NOAA decides to drop current recon down to 5,000ft or less


Never mind NOAA recon flying 5,180ft