ATL: IRENE - Models

[CrazyC83]

As the models continue to shift eastward, I expect the forecast track to be shifted slightly more east. As I called it a few days ago, it is forecasted to turn north, east of Florida.

At this point, there might be a chance it might escape the Southeast completely. How is the ridge supposed to hold up farther north though? Any chance it could get pushed into the Northeast?

[Vortex]

H+78 approaching SE FL and intensifying...synoptics seem very reasonable.


http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_078l.gif

[chris_fit]

18z NAM 84hrs



Uploaded with ImageShack.us

[Aric Dunn]

and still heading wnw at end of run.. vs NW or NNW at the 12z ..
wait scratch that.. its heading NW

but geezz look at that ridging building in..if the nam when any farther I bet it would turn back wnw ..

[Vortex]

H+84 landfall SFL


http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_084l.gif

[Kory]

and still heading wnw at end of run.. vs NW or NNW at the 12z ..

Right now the NAM is an outlier and so is the GFDL. I still expect a SC/NC impact. Not ruling out a complete offshore track as the 12z GFS almost accomplished.

[Aric Dunn]

and still heading wnw at end of run.. vs NW or NNW at the 12z ..

Right now the NAM is an outlier and so is the GFDL. I still expect a SC/NC impact. Not ruling out a complete offshore track as the 12z GFS almost accomplished.

well if the NAM has some sounding data in it.. and it shifted west .. the 18z gfs should as well.

[ronjon]

It would ironic if the NAM and GFDL verified for Irene - one of most vilified tropical cyclone models (other than NOGAPs) versus one of the most highly respected. I don't know if the synoptics might be changing or its just the NAM.

[sicktght311]

So just to recap what i've seen with the model runs today in the 8 hours i've been at work..........

9am - Runs parallel to florida coast, slamming NC/SC border, then up to long island as a cat 1
12pm - Makes landfall in SoFla, runs directly up the state of florida, then along the eastern seaboard
5pm - Runs over miami, and then maybe the gulf coast, maybe even gulf?

moral of story.........i'll check back tomorrow for what i'm sure will be another 8 hours of model swings

[Vortex]

other than the obvious why does the GFDL(superior hurricane model) and NAM(excellent with synoptics) force Irene into FL while the others have a sharp curve east???? Maybe someone with abit more backround than myself could share??? Thx

[Aric Dunn]

just compared the initialized 500mb heights from the NAM 18z and the 12z gfs and the Nam has the ridging extending farther west.

[Scorpion]

other than the obvious why does the GFDL(superior hurricane model) and NAM(excellent with synoptics) force Irene into FL while the others have a sharp curve east???? Maybe someone with abit more backround than myself could share??? Thx

NAM has always been bad and GFDL has seemed to have some issues. If the new models start to trend more west then they might have some credence though.

[Kory]

As the models continue to shift eastward, I expect the forecast track to be shifted slightly more east. As I called it a few days ago, it is forecasted to turn north, east of Florida.

At this point, there might be a chance it might escape the Southeast completely. How is the ridge supposed to hold up farther north though? Any chance it could get pushed into the Northeast?

No, I expect Irene to erode the ridge a bit more since she will be pushing category 2/3 strength by Thursday and Friday. I don't see a northeast US direct landfall, but a recurve just offshore of North Carolina is possible, but not likely.

[clfenwi]

Found this under the NOUS42 header (my apologies if someone posted this earlier), however I haven't found initialization notes for the 18Z NAM

SENIOR DUTY METEOROLOGIST NWS ADMINISTRATIVE MESSAGE
NWS NCEP CENTRAL OPERATIONS CAMP SPRINGS MD
1340Z MON AUG 22 2011

[EDITED]

THE NATIONAL HURRICANE CENTER IS REQUESTING SPECIAL 6-HOURLY UPPER
AIR RELEASES BEGINNING AT 18Z TODAY FROM THE FOLLOWING STATIONS:
KEY WEST, MIAMI, TAMPA, JACKSONVILLE, TALLAHASSEE, SLIDELL,
JACKSON, BIRMINGHAM, PEACHTREE CITY, CHARLESTON, MOREHEAD CITY,
GREENSBORO, NASHVILLE, WILMINGTON, PITTSBURGH, BLACKSBURG,
STERLING AND WALLOPS ISLAND.

What type of data does this add to the models (in general or the 18z in particular) that wasn't there before? Does this mke the 18z models more special than it normally is (as an intermediate run)?

Upper air observations derived from weather balloons usually go into the models only twice a day, 00Z and 12Z. So yes, the 18Z models are getting a little bit more in the way of observations than normal. Looks like most that were requested (if not all) did get into the data dump. Also looks like the first few dropsondes from the G-IV mission made it in as well.

[storm4u]

waiting for the gfs to run the nam sucks at tropical weather fwiw

[Aric Dunn]

other than the obvious why does the GFDL(superior hurricane model) and NAM(excellent with synoptics) force Irene into FL while the others have a sharp curve east???? Maybe someone with abit more backround than myself could share??? Thx

well im not the best with models compared to some. but the GFDL could have a better handle on what Stewart was talking about in the 5am discussion. the GFDL has much better resolution than the GFS and the global models which have a hard time with smaller features.

[Aric Dunn]

waiting for the gfs to run the nam sucks at tropical weather fwiw

we are not looking at the NAM for track.. the synoptics are a different story. NAM does quite well with that.

[otowntiger]

and still heading wnw at end of run.. vs NW or NNW at the 12z ..

Right now the NAM is an outlier and so is the GFDL. I still expect a SC/NC impact. Not ruling out a complete offshore track as the 12z GFS almost accomplished.

well if the NAM has some sounding data in it.. and it shifted west .. the 18z gfs should as well.

But why does the NHC seem to have increasing confidence in model agreement that will take the storm up the current forecasted track? I keep hearing about this model and that model shifting west but the NHC's track is holding steady and/or shifting east along with the 'model concensus'.

[CourierPR]

As the models continue to shift eastward, I expect the forecast track to be shifted slightly more east. As I called it a few days ago, it is forecasted to turn north, east of Florida.

At this point, there might be a chance it might escape the Southeast completely. How is the ridge supposed to hold up farther north though? Any chance it could get pushed into the Northeast?

No, I expect Irene to erode the ridge a bit more since she will be pushing category 2/3 strength by Thursday and Friday. I don't see a northeast US direct landfall, but a recurve just offshore of North Carolina is possible, but not likely.

She might also pump up the ridge. I think it's too soon to be making sweeping statements with such certainty.

[ronjon]

other than the obvious why does the GFDL(superior hurricane model) and NAM(excellent with synoptics) force Irene into FL while the others have a sharp curve east???? Maybe someone with abit more backround than myself could share??? Thx

Yeah the NAM has stronger 500 mb ridging over the western Atlantic which is similar to the GFDL. The NAM is a mesoscale model and the GFDL is very high in resolution - are they seeing something the globals can't?