ATL: ISAAC - Models

[KWT]

Ensembles look a touch further west, with the op run right in the middle of the ensembles.

Until this gets a decent center any model estimates in the short term are prone to large errors.

[Dean4Storms]

If we really want to know where Isaac is headed send that G-IV to sample off the Pacific NW!!

[SFLcane]

I suspect the GFS within the next few runs will give way to the Euro. As kwt mentioned the GFS ensembles have trended west. Even though things can change iam starting to feel better here in SFL in terms of serious impacts.

[tolakram]

Reposting a saved image with annoying comments by me.

Last year, from 96 hours to 120 hours the euro is <5% more accurate than the GFS. It's the middle time frame where the euro performs very very well. 96+ this is why the consensus is so important. Both the major models are pretty good, with a slight bias to the euro. You can claim otherwise, but I'll take the data for what it is.

The problem with >96 is that everything is pretty inaccurate, less than 40% skill over climatology.

[Senobia]

I went through the past few pages of replies, saw the westward model shifts and the mention of recon data and now - I have a question.

What has to happen, in terms of models and such, for the NHC to re-write the projected path of Isaac to reflect all of the westerly stuff that has transpired today? Is there enough data/info to expect it already or is all the westerly data coming in today just normal flip-floppin' that, in the end, has no bearing on the track?

[jlauderdal]

If we really want to know where Isaac is headed send that G-IV to sample off the Pacific NW!!

NWS offices will be providing that data from the special soundings they are doing.

[BigB0882]

3 of those GFS ensembles have this thing right over my house. None of the GFS models have landfall as far west as the Euro Operational, though. I tend to want to focus on somewhere between TX and FL but I know that you can't always go down the middle when talking about models. I have often heard posters mention that a storm can go NE or continue WNW but it can't head N. Not sure if this is one of those cases but for now, everyone needs to keep an eye if you are anywhere from TX to FL.

[ROCK]

If we really want to know where Isaac is headed send that G-IV to sample off the Pacific NW!!

NWS offices will be providing that data from the special soundings they are doing.

yep the ballons will be flying for sure.....I believe I saw they requested it...

[Cyclenall]

Wow, another crazy Euro run that makes SIX runs in a row of the same outcome...Gulf hurricane taking a more southern route. This is a solid trend by the Euro, you can't ignore 6 runs in a row showing that from the best model generally. It was even wacky at the start which leaves even more of a door open for sharp changes. And that far west when some were thinking it was going inline with the rest . I just keep waiting for the NHC to change it (beginning and middle period) somewhat but there it stays. Consider 3 days ago the Euro has correctly forecasted Isaac's strength and track for the most part.

This morning I dreamed of all of what has been happening the past 6 hours to a tee, lots of discussion and the Euro taking a huge west shift late in the period for the 12z run. I had mini-dreams of that same image showing that wnw movement in the Gulf just like what it shows, foretelling!!!!

I'll just quote this one so its on the next page, that is slightly telling of a more westwards shift at the end period (after 96 hours) but they are fairly clustered together here. Some members are showing LA more here than before.

[ROCK]

this is better resolution for the EURO run...thought you SWLA folks would like to see this...not that I hug the EURO or anything...

http://www.weatherbellmodels.com/weathe ... 0_mex2.gif

[Jevo]

GOOD NEWS!

Dr. Rick Knabb ‏@NHCDirector
@TheFLHurricane: @NHCDirector When model runs reflect G-IV data? #Isaac @NHCDirector Data will get into 00Z (8 pm ET) runs, used for 5 am advisory. MT

Twitter is great

[Hurricaneman]

The Euro is showing what Im thinking for the next 3 days, The vortmax at 17N goes into Hispaniola while the one the recon shows as the center goes south of Hispaniola and makes landfall in western Cuba

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.

[Air Force Met]

This is storm is a giant dud. just an opinion by forecast

We're so sorry mother nature can't accommodate your appetite for death and destruction.

[Houstonia]

This is storm is a giant dud. just an opinion by forecast

We're so sorry mother nature can't accommodate your appetite for death and destruction.

AFM, if I were able, I would "like" your comment x 1000!!!

[Houstonia]

From the Hou/Galv 3:17 pm weather discussion:

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
317 PM CDT THU AUG 23 2012

... edited for brevity

UPPER LOW OVER 4 CORNERS SHOULD QUICKLY MOVE INTO THE PLAINS OVER
FRI INTO SAT. LEE CYCLOGENESIS OVER THE PLAINS SHOULD HELP
INCREASE WINDS AND MOISTURE SO THINK NAM/GFS ARE ON TRACK WITH SCT
THUNDERSTORM ACTIVITY TOMORROW THROUGH POSSIBLE SUN. GFS HOLD ON
TO HIGHER MOISTURE INTO SUN SO THINK 30 POPS FOR BOTH DAYS. BEST
CHANCES STILL LOOK TO BE ON FRIDAY. AGAIN MAIN THREATS LOOK TO BE
BRIEF LOCALLY HEAVY RAINFALL AND PERHAPS A FUNNEL CLOUD/WATERSPOUT
AROUND THE COASTAL AREAS AND BAYS.

YESTERDAY THE QUESTION MARK OVER THE EXTENDED FORECAST FOR NEXT
WEEK WAS SHRINKING. THAT QUESTION MARK GOT A LOT BIGGER AS THE GFS
AND ECMWF 12Z RUNS ARE QUITE DIFFERENT. BOTH MODELS HAVE A MORE
WESTWARD SHIFT IN THE TRACK OF ISAAC. THE GFS MAINTAINS MODEL
TRACK CONSENSUS WHERE THE ECMWF HAS ISAAC IMPACTING PORTIONS OF
SE TX NEXT WED/THUR/FRI. GRANTED THIS IS THE FAR OUTER REACHES OF
THE FORECAST BUT STILL NEED TO KEEP AN EYE ON THE MODEL TRENDS
THROUGH THE WEEKEND. AS FOR NOW THE FORECAST WILL KEEP 20 POPS IN
THE FORECAST AND LEAN MORE ON THE GFS SINCE THE ECMWF IS STILL A
DEPARTURE YET ONE THAT NEEDS TO BE MONITORED.

[Jevo]

18z NAM +84 likes SE FL (left of prev runs)

[SouthFLTropics]

18z NAM +84 likes SE FL (left of prev runs)

Well that settles it...we're not getting hit if the NAM is showing it...lol

[USTropics]

If we really want to know where Isaac is headed send that G-IV to sample off the Pacific NW!!

NWS offices will be providing that data from the special soundings they are doing.

yep the ballons will be flying for sure.....I believe I saw they requested it...

Just to clarify the NCEP asked for radiosonde observations (balloon launches) every 6 hours from the NWS WFOs starting yesterday for Florida, Georgia, Mississippi, and Alabama.

http://weather.noaa.gov/tgstatus/

[karenfromheaven]

What has to happen, in terms of models and such, for the NHC to re-write the projected path of Isaac to reflect all of the westerly stuff that has transpired today? Is there enough data/info to expect it already or is all the westerly data coming in today just normal flip-floppin' that, in the end, has no bearing on the track?

Based on their 5 PM discussion, I would say they would need to see the GFDL and HWRF model tracks shift west.

[KWT]

18z GFS run will be coming out soon. I wonder how the GFS will handle the system in the short term. Really the 24-48hrs period is SO key for how this system ends up evolving and its track IMO.