Bertha may pose a long-range threat to the U.S.
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
Reader Comments
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Drakoen do you believe that Bertha will be north or south of the forecast point in 5 days?
South not much confidence in that though.
THE NEW
NHC INTENSITY FORECAST IS UNCHANGED THROUGH 48 HOURS BUT NOW
PREDICTS BERTHA TO REACH HURRICANE STRENGTH IN 72 HOURS.
THEREAFTER...DUE TO UNCERTAINTIES IN THE AMOUNT OF PREDICTED
SHEAR...THE INTENSITY IS HELD A LITTLE BELOW THE LGEM...SHIPS...AND
GFDL MODELS WHICH SHOW ADDITIONAL INTENSIFICATION.
Some people would love that, but I second this comment. I got lucky and found a met job that is 8:30 to 5 weekdays with all government holidays off. Do I plan on working the night shift on Christmas Eve...no.
Operational forecasters throughout NWS probably have 5 interesting weather days a year in their area on their shift. That would be enough for some folks. I would get bored in a real hurry with forecasts that are of the sort that tomorrow will be a lot like today.
Thanks for your input IKE, I greatly appreciated it. And yes, I too fear the same, you just wait till that 5pm update comes out, right IKE?
Agree.
Ummmmmmmm.
If you look back at the surface map I posted the Western periphery of the high is all the way back into Texas. If Bertha is where the map shows it at that time there will not be enough time to erode so extensive a high in order to allow the system to make what will then be a "U" turn.
A trough would have to come off the East coast and fracture the high between Fla. and Bermuda in order to create a weakness for the storm to exit through. The timing on that will be awfully tricky if it happens at all.
As intensififcation is now forcast to cane status bertha to me is more likely to feel the tug and move in a WNW-NW fashion in the days ahead
Agreed. If intensification were to occur that fast then the chance for a recurving storm would increase especially with the second trof. Lets hope its right.
Press - great idea...not staying if it heads this way.
all so i olny see a red X on the GFS that you where trying to show me
Watch out Carolinas
315. kmanislander 10:15 AM CDT on July 05, 2008
Ike
If you look back at the surface map I posted the Western periphery of the high is all the way back into Texas. If Bertha is where the map shows it at that time there will not be enough time to erode so extensive a high in order to allow the system to make what will then be a "U" turn.
A trough would have to come off the East coast and fracture the high between Fla. and Bermuda in order to create a weakness for the storm to exit through. The timing on that will be awfully tricky if it happens at all.
Agree....one avenue is to look at the extended discussions out of the various offices.
I wouldn't jump to any conclusions just yet. Bertha is still too far away from land for concern to amount. Remember, all we are relying upon are computer models working on a hypothetical representation of the future, which may or may not happen. As Bertha nears the islands (or goes to the north of them), then we should be able to look at the CONUS's chances of getting affected with more certainty.
very strong eatl wave with a 1012mb low, near 11N moving west at 15 mph. this looks like soon to be chritened Cristobal. this system at this point could be a threat to the islands next weekend
I dont see many pics of Fish now do I?
lol
reserved.
456 thanks by the way are you going to have a update on your blog today ???
all so i olny see a red X on the GFS that you where trying to show me
I will update this afternoon.
Sorry about the broken link...i fiexed it.
dont you all think your for geting some in
what about wind shear by that time
the storm could get tourn a part by that time has well dont for get that
Exactly press
I am interested to see if we start getting a standard variation between the 00z/12z runs, and the 06/18z runs of the GFS. One set being more southerly then the other. Seems the GFS does this on occasion? Almost like it is debating with itself...
Long term /Monday night through Friday/...
Bermuda high remains in place over the Atlantic...and persistent SW
flow will allow a very warm and humid airmass to overspread the
region. Highs will be in the upper 80s to around 90 with dewpoints
in the upper 60s. Diurnally driven convection will result in
scattered evening showers and thunderstorms Monday night...then again
on Tuesday afternoon/evening. A cold front will push into the region on
Wednesday...moving south of the area Wednesday night and becoming nearly
stationary as high pressure builds from the north.........
weakness for Bertha to turn?
=======================================
stormfury, It maybe more interesting for the islands and beyond than Bertha at some point in the future.
The thing that has me a bit concerned is how both the GFS/ECMWF both build a pretty significant ridge out 4-5 days.
"Long term /Tuesday through Saturday/...
as of 3 am Saturday...much of the same with Bermuda high in place
through most of the extended period. Middle to upper level support for
afternoon convection diminishes heading into middle week as middle to
upper ridge builds westward over the southeast Continental U.S.. as ridge
builds westward...local area gets into a band of westerlies at middle
levels which will help diminish deep layer moisture in the
atmosphere...but overall pcp water values will remain up around 1.8
inches."
Link
344...this from the Wilmington,NC extended...
"Long term /Tuesday through Saturday/...
as of 3 am Saturday...much of the same with Bermuda high in place
through most of the extended period. Middle to upper level support for
afternoon convection diminishes heading into middle week as middle to
upper ridge builds westward over the southeast Continental U.S.. as ridge
builds westward...local area gets into a band of westerlies at middle
levels which will help diminish deep layer moisture in the
atmosphere...but overall pcp water values will remain up around 1.8
inches."
Uh...that doesn't sound good......
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