Bertha may pose a long-range threat to the U.S.

By: Dr. Jeff Masters , 12:43 PM GMT on July 05, 2008

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Tropical Storm Bertha has maintained it's strength overnight, but is having trouble with Sea Surface Temperatures (SSTs) of 25°C--one degree below the threshold of 26°C considered beneficial for tropical storms. This morning's QuikSCAT pass missed Bertha, but last night's pass confirmed winds of at least 40mph. Satellite estimates of Bertha's strength have consistently put the storm's strength at 50 mph over the past day. The storm is under about 10-15 knots of wind shear.


Figure 1. Latest satellite image of Bertha.

The forecast
The models are now more confident that Bertha will not take a turn to the north east of Bermuda, with two models--the UKMET and NOGAPS--calling for the storm to pass very near the northern Lesser Antilles Islands by Tuesday night and Wednesday morning. These islands should anticipate the possibility of tropical storm conditions as early as Tuesday night, even though the current official track keeps Bertha well north of the islands. Bertha may be large enough to bring tropical storm force winds 100-200 miles from the center by Tuesday. A threat to the East Coast of the U.S. is now possible, with such an event most likely to occur about 7-10 days from now. It is also possible that high wind shear will tear apart Bertha (as predicted by the ECMWF model), or that the storm will recurve to the north just east of North Carolina, missing the U.S. The long range track of Bertha is highly uncertain, and it is too early to speculate how likely each of these scenarios is.

By Sunday morning, Bertha will be over SSTs of 26°C, which will warm to 27°C by Monday and 28°C Tuesday. this should allow Bertha to intensify to near Category 1 hurricane strength. However, by Tuesday, wind shear is expected to increase to 20 knots and remain high for several days, as Bertha encounters a branch of the subtropical jet stream. The higher shear should weaken the storm.

Elsewhere in the tropics
There are no threat areas to discuss in the tropical Atlantic, and none of the models are forecasting tropical storm formation in the next seven days.

I'll post an update by Sunday afternoon.
Jeff Masters

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2818. oddspeed
8:29 PM GMT on July 06, 2008
an interesting model

Member Since: September 4, 2007 Posts: 0 Comments: 236
2817. sarasotaman
4:57 PM GMT on July 06, 2008
JFV great vid! So it backs up that the storm will stay more west than north. now with the slow down in speed we should see a near cat2 close to the Bahammas.
2816. msphar
4:43 PM GMT on July 06, 2008
Should miss the islands and Puerto Rico as it continues to climb in Latitude the next couple of days.
Member Since: August 20, 2006 Posts: 0 Comments: 289
2815. WXHam
4:39 PM GMT on July 06, 2008
NHC Model Composite over Google Earth. img

Member Since: July 1, 2008 Posts: 0 Comments: 33
2813. Cavin Rawlins
4:31 PM GMT on July 06, 2008
new blog
Member Since: July 24, 2005 Posts: 407 Comments: 19076
2812. moonlightcowboy
4:31 PM GMT on July 06, 2008
NEW BLOG
Member Since: July 9, 2006 Posts: 184 Comments: 29610
2811. MZV
4:30 PM GMT on July 06, 2008
#2787 - Yes that vid from Hurricanecity was interesting. I would agree that when things get tough, the low-level flow predominates on movement. (I remember watching the upper levels of TS Chris get completely separated from the low level... which continued moving west.)
Member Since: July 3, 2008 Posts: 0 Comments: 227
2810. weathersp
4:30 PM GMT on July 06, 2008
GFS has been an outlier for a few runs.. so its either dead wrong or its right.
Member Since: January 14, 2007 Posts: 17 Comments: 4140
2809. beell
4:29 PM GMT on July 06, 2008
2787.
Good vid JFV,
Thanks
Member Since: September 11, 2007 Posts: 143 Comments: 16729
2808. rareaire
4:28 PM GMT on July 06, 2008
im with you 0311. probably an error in Judgement but I have looked it over made an novices informed decision and I heard JIm Cantore was in Miami!! lol
Member Since: August 19, 2007 Posts: 0 Comments: 1601
2807. extreme236
4:27 PM GMT on July 06, 2008
2802.

Yea and my Common Sense 12Z model run doesn't show an open wave lol
Member Since: August 2, 2007 Posts: 19 Comments: 19234
2806. IKE
4:26 PM GMT on July 06, 2008
2803. JFV 11:25 AM CDT on July 06, 2008
The models seriously need to get their acts together, this constant unpredictabilty from then is simply not tolerable any longer to say the least! I saw it too already IKE! where does it take it by the way?


Parks it south of Bermuda...I guess she's considering a vacation on the tax-free island.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
2805. extreme236
4:26 PM GMT on July 06, 2008
Well the GFS isn't an intensity model so its not worth putting much stock in to how strong it shows a system to be.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
2804. IKE
4:25 PM GMT on July 06, 2008
I wouldn't put a lot into the strength it shows...it would show Dean last year at 1008 mb's when it was a strong hurricane.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
2802. Cavin Rawlins
4:24 PM GMT on July 06, 2008
The only model I need is my common sense.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
2801. IKE
4:23 PM GMT on July 06, 2008
The GFS has been showing a weaker system for a few runs...it did that last year on systems.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
2800. HurakanPR
4:23 PM GMT on July 06, 2008
Bahahurican,agree with you 100%. very well said.
2799. extreme236
4:23 PM GMT on July 06, 2008
2796.

I'm gonna toss out that run...unless I see that again on the 18Z and 00Z runs I'm not even gonna pay any attention to that.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
2797. Cavin Rawlins
4:22 PM GMT on July 06, 2008
2790. sporteguy03 12:16 PM AST on July 06, 2008
456,
thoughts on the GFS now with an Open Wave?


Just looked at it...Even though wind shear may increase some over Bertha, it isnt suppose to leave it an open wave, thats quite a weakening there from hurricane to open wave. Not going with it.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
2796. IKE
4:21 PM GMT on July 06, 2008
12Z GFS...Bertha at 120 hours + the system coming off of Africa....

Link

Member Since: June 9, 2005 Posts: 23 Comments: 37858
2795. Patrap
4:20 PM GMT on July 06, 2008
WAVE tracking winds Link
Member Since: July 3, 2005 Posts: 426 Comments: 128654
2794. TropicalNonsense
4:18 PM GMT on July 06, 2008
I keep telling ya the models are all goofy right now. They all show an acclerated
unnatural movement of the ridge which does not look normal at all to me.

give them 48 hours and the NHC will know with less guesswork! until then she is
weak, small and un affecting any land for the time being. But still interesting to watch.
I am just excited to have a storm to track with potential even if she's a fish. lol
Member Since: July 3, 2007 Posts: 0 Comments: 524
2793. Cavin Rawlins
4:17 PM GMT on July 06, 2008
2783. stoormfury 12:12 PM AST on July 06, 2008

Yea...I guess we have days to watch the other system but for now Bertha seems to the highlight of the Atlantic, and i dont blame her...lol
Member Since: July 24, 2005 Posts: 407 Comments: 19076
2792. Patrap
4:16 PM GMT on July 06, 2008
Morphed Integrated Microwave Imagery at CIMSS (MIMIC)
Version 1 TS Bertha
Vmax 45knts Link



Cooperative Institute for Meteorological Satellite Studies
Space Science and Engineering Center / University of Wisconsin-Madison

Tropical Cyclones ...A Satellite Perspective Link

Frequently Asked Questions Link

Member Since: July 3, 2005 Posts: 426 Comments: 128654
2791. rainraingoaway
4:16 PM GMT on July 06, 2008
Morning all. Everybody's fired up as usual!
Member Since: August 19, 2007 Posts: 3 Comments: 273
2790. sporteguy03
4:16 PM GMT on July 06, 2008
456,
thoughts on the GFS now with an Open Wave?
Member Since: July 7, 2005 Posts: 0 Comments: 5351
2789. extreme236
4:15 PM GMT on July 06, 2008
2784.

Certainly looking a little better organized and not even close to what the wacko GFS was showing on that run.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
2788. HurakanPR
4:15 PM GMT on July 06, 2008
Weatherfreak ,Ike did a few post back.
2786. HurakanPR
4:13 PM GMT on July 06, 2008
Agree Stormhype, including you.
2785. BahaHurican
4:13 PM GMT on July 06, 2008
2765. HurakanPR 12:01 PM EDT on July 06, 2008
mmmm What's that of referring to people as "those Hatians"!

[-]minus and [!]flag, Hura. These are people who are not talking about the weather, and they are not talking about anything else that is sensible, either.
Member Since: October 25, 2005 Posts: 19 Comments: 22322
2784. Cavin Rawlins
4:13 PM GMT on July 06, 2008
2780, that is what I'm thinking too. Bertha needs to take that momentum wnw or nw.

Another shot of Bertha and the Antilles

Member Since: July 24, 2005 Posts: 407 Comments: 19076
2783. stoormfury
4:12 PM GMT on July 06, 2008
456 the blog is BERTHARISED to day and the other area south east of it is totally disregarded. i guess the threat from this disturbance is not real for the CONUS right now. let us wait for a couple of days when it might be apparent that system will head for the GOMEX then all hell will break loose. In the meantime i will continue to monitor this system as it appears to have the potential to be the next name storm
Member Since: August 22, 2006 Posts: 0 Comments: 2713
2782. MZV
4:11 PM GMT on July 06, 2008
I have to agree that shear is not much of a problem for Bertha *right now*. Think back to Alberto... THAT was what a sheared system looks like. Bertha is doing pretty well for the conditions.
Member Since: July 3, 2008 Posts: 0 Comments: 227
2781. extreme236
4:11 PM GMT on July 06, 2008
2777.

Well if I get a ban I hope the other trolls do to.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
2780. HurakanPR
4:11 PM GMT on July 06, 2008
Hi, Still, don't see the northwestward move of Bertha to catch the next forecast TF Point,and she is approaching 46w.
2779. sporteguy03
4:10 PM GMT on July 06, 2008
2771
We go from hurricane to open wave?? Seems pretty inconsistent.
Member Since: July 7, 2005 Posts: 0 Comments: 5351
2778. BahaHurican
4:10 PM GMT on July 06, 2008
Latest vis floater on Bertha:

Member Since: October 25, 2005 Posts: 19 Comments: 22322
2777. ShenValleyFlyFish
4:10 PM GMT on July 06, 2008
2760. extreme236

Circumventing a ban will likely get you one as well.

Wise up folks. This isn't all that hard.
Member Since: September 9, 2007 Posts: 36 Comments: 4687
2776. extreme236
4:08 PM GMT on July 06, 2008
2771.

That has to be a faulty run of some sort as it starts her off as a barely closed low.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
2775. Cavin Rawlins
4:08 PM GMT on July 06, 2008
She's define nontheless

Member Since: July 24, 2005 Posts: 407 Comments: 19076
2774. ShenValleyFlyFish
4:07 PM GMT on July 06, 2008
2751. Patrap

lol
Member Since: September 9, 2007 Posts: 36 Comments: 4687
2773. TropicalNonsense
4:07 PM GMT on July 06, 2008
Bertha has a good tight circulation but is looking kinda small. History shows smaller storms
trend further west when left uninhibited by troughs etc. I remember "Andrew" was early and
also looked this way before he hit the gulf stream and smashed florida back in the 90's.


Member Since: July 3, 2007 Posts: 0 Comments: 524
2772. extreme236
4:07 PM GMT on July 06, 2008
2770.

By looking at the visible imagery it looks like Bertha has a tight inner core of some sort. I can notice this feature better on Dr. M's satellite on his blog post if you scroll up the page.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
2771. hurricane23
4:06 PM GMT on July 06, 2008
My My latest 12z GFS has bertha as an open wave.
Member Since: May 14, 2006 Posts: 8 Comments: 13804
2770. Cavin Rawlins
4:05 PM GMT on July 06, 2008
On visible imagery, Bertha is attempting to expand her mass. Some of the low clouds south of her center is beginning to deepen...but at a slow rate and that is due to dry air.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
2769. FLWeatherFreak91
4:03 PM GMT on July 06, 2008
mmmm What's that of referring to people as "those Hatians"!

Who said that?
Member Since: December 1, 2006 Posts: 2 Comments: 3625
2768. pandorasbox
4:03 PM GMT on July 06, 2008
good morning to all..ok..good afternoon now...after the latest runs, when is the turn supposed to take place? I am seeing with my inexperienced eye, by Tuesday?

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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.