Global model runs discussion

[gatorcane]

GFS 700MB RH showing more and more dry air entering the tropics. The pattern continues, at least as far as the GFS is concerned.

Looking at the wide Atlantic satellite shot from NHC's site this morning, once the stubborn East Coast trough ejects Bertha and the surface trough over Florida off to the north and then Northeast, it looks like it will be tough to find thunderstorms across the entire Atlantic basin.

Right now there is hardly a thunderstorm to be found from the Caribbean through all of the Atlantic to Africa and Africa looks a bit drier than I would expect for this time of year too - no wonder models are picking up zilch for the forseeable future!

Saved image:

[CYCLONE MIKE]

Besides the dry air we have troughs on a weekly basis that are putting the lid on any chance of home brew activity. Which translates to screaming shear across the gulf and east coast. We had two cold front make it all the way to the gulf coast as well last month.

AS WE HEAD INTO THE SECOND HALF OF THE WEEKEND
THERE ARE SIGNIFICANT DIFFERENCES IN THE STRENGTH AND BREADTH OF THE
RIDGE OVER THE CONUS AND THE DEVELOPMENT OF A NEW ERN CONUS TROUGH
WHICH HAS BEEN A THEME THIS ENTIRE YEAR. EVENTUALLY BOTH THE GFS AND
ECMWF SHOW THE REDEVELOPMENT OF THE ERN CONUS TROUGH WITH MAINLY
TIMING ISSUES

[Ntxw]

GFS 700MB RH showing more and more dry air entering the tropics. The pattern continues, at least as far as the GFS is concerned.

Looking at the wide Atlantic satellite shot from NHC's site this morning, once the stubborn East Coast trough ejects Bertha and the surface trough over Florida off to the north and then Northeast, it looks like it will be tough to find thunderstorms across the entire Atlantic basin.

Right now there is hardly a thunderstorm to be found from the Caribbean through all of the Atlantic to Africa and Africa looks a bit drier than I would expect for this time of year too - no wonder models are picking up zilch for the forseeable future!

Bertha will cause a wave breaking event in the far North Atlantic which raises heights across the basin below kind of like after Arthur with sinking air for a week or two which explains the models lacking activity. My guess is after that week they will pick up something for week 2 and 3.

[ConvergenceZone]

Since we are getting close to week 2 in August and there isn't anything even remotely coming together yet, I'm thinking that our "C' storm will come either at the end of week 3 in August or the very beginning of week 4......Perhaps we will start seeing improving conditions in the Atlantic in about a week.

I still think September will be busier with 3 named storms.

[gatorcane]

GFS 700MB RH showing more and more dry air entering the tropics. The pattern continues, at least as far as the GFS is concerned.

Looking at the wide Atlantic satellite shot from NHC's site this morning, once the stubborn East Coast trough ejects Bertha and the surface trough over Florida off to the north and then Northeast, it looks like it will be tough to find thunderstorms across the entire Atlantic basin.

Right now there is hardly a thunderstorm to be found from the Caribbean through all of the Atlantic to Africa and Africa looks a bit drier than I would expect for this time of year too - no wonder models are picking up zilch for the forseeable future!

Bertha will cause a wave breaking event in the far North Atlantic which raises heights across the basin below kind of like after Arthur with sinking air for a week or two which explains the models lacking activity. My guess is after that week they will pick up something for week 2 and 3.

Yeah I am thinking by week 3 things should start picking up across the Atlantic especially as the CFS has been quite insistent on some Cape Verde activity starting around the end of the third-week of August.

[gatorcane]

The 12Z GEM model is showing a strong Cape Verde 1004MB low moving offshore Africa in the long-range:

Aug 13th saved image:


The 12Z GFS model is showing a low but not as strong at 1012MB. This weak low moves west across the MDR in the very long-range:

Aug 14th saved image:

[Hammy]

It looks like over the next few weeks that a few tropical waves will gradually moisten the MDR.

[blp]

The CFS is really optimistic on development in late August. It has the strongest wave all season exiting Africa on the 23rd. I normally don't like to pick out specific areas on the CFS but since the GFS and CMC are hinting at lowering pressures late in August it might actually be believable.

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=noat&MODELL=cfs&MODELLTYP=1&BASE=-&VAR=pslv&HH=480&ZOOM=0&ARCHIV=0&RES=0

[Hurricaneman]

Things seem to look a lot more favorable around 7 to 10 days from now and if models are right then after that will be a period of tropical activity for the atlantic for the peak of hurricane season

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products

[blp]

Euro starting to hint at lowering pressures toward the end of its run.

[Hurricaneman]

Euro starting to hint at lowering pressures toward the end of its run.

yep and the 6zGFS shows something pretty similar and shows shows some tropical development near the end of the run and a sharp wave nearing the Bahamas in 16 days heck the Euro even shows the 6zGFS Bahamas wave nearing the windward islands in this map so as I suspect 7 to 10 days from now may show the wave train and some tropical development

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products

[blp]

The 12z Euro is showing a very nice wave off the Cape Verde islands and what looks like a closed low over Africa. The 00z run also showed similar lows. This is also very similar to what the CFS said would happen a few days ago. The GFS is also hinting at this.

High resolution:



Low resolution:

[cycloneye]

UKMET is upgraded

If the upgrade of UKMET works good,then GFS and ECMWF may have good company as a third altrernative to look at when modeling of Tropical Cyclones is concerned.

http://www.metoffice.gov.uk/media/pdf/s ... i_v2.0.pdf

[AJC3]

The 12z Euro is showing a very nice wave off the Cape Verde islands and what looks like a closed low over Africa. The 00z run also showed similar lows. This is also very similar to what the CFS said would happen a few days ago. The GFS is also hinting at this.

<snip>

Low resolution:

A caveat about the low over Africa. There's a semi-permanent Saharan heat low there during the summer, the western extension of which extends into west Africa. given the high latitude of that low center (22N), it's quite likely that's at least partially responsible for what you're seeing.

[gatorcane]

UKMET is upgraded

If the upgrade of UKMET works good,then GFS and ECMWF may have good company as a third altrernative to look at when modeling of Tropical Cyclones is concerned.

http://www.metoffice.gov.uk/media/pdf/s ... i_v2.0.pdf

looks very promising for the UKMET. Will be interested in seeing how it performs.

[somethingfunny]

In past seasons we would see the long-range (one to two weeks out) GFS push that Saharan Heat Low offshore from Mauritania fairly often and deepen. I'm not sure why it happens so often in the simulation but it doesn't usually happen in reality, and certainly not at the strengths depicted in the voodoo timeframe if it happens at all. Tropical waves don't exist and Cape Verde just storms don't develop at that latitude.

If that Saharan Low did push offshore it would just bring a reinforcing invasion of dust and dry air to the Eastern Atlantic anyway.

[Hurricaneman]

the 6zGFS shows a low coming off of Africa at around 168{an area behind pouch 13} and is at the end of the run half way between the Cape Verde Islands and the Lesser Antilles with a pretty firm ridge that may cause headaches for the US east coast if the ridge remains like it is in this run but as we all know the pattern could change and be quite different to this

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products

[Hurricaneman]

The 18z GFS has a low coming off of Africa at 126hrs and basically pulls a similar track to Fran in 1996 with it by 360hrs so while the details most definitely will change we'll have to see what it looks like when it comes offshore

What I do take away from this is that it produces a pattern that would cause landfalls anywhere from the Florida east coast on up the eastern seaboard so by mid August we may have to watch these African waves along the east coast with the ridge being progged by the GFS and the Euro

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products

[blp]

The MJO looks to be making a strong showing in two weeks over the Eastern Atlantic. That adds some credability in what the models are showing with strong waves appearing in that timeframe.

[somethingfunny]

The 0z GFS has a possible homebrew off the East Coast next week.