ATL: IRMA - Models

[plasticup]

What the hell happened overnight with the GFS and Euro? How did the Euro become the Eastern outlier?

That trough was always a borderline feature, just deep enough to pull Irma up. And now it misses.

Also, this is what happens when the hurricane hunters deploy: the models start to cluster once they have real data.

[stormreader]

What the hell happened overnight with the GFS and Euro? How did the Euro become the Eastern outlier?

Makes you wonder. While both models in the beginning were too far east, at least the Euro sort of led the way by inching closer and closer to the Fl Atlantic coast. But now other models have "overtaken" it and have edged further west than it has. One possibility voiced here is that things will swing back a little east, and the current Euro will turn out to be closer to reality. I don't mean to be cryptic, but I think there is another possibility, Gonna wait some to voice it, but really don't know that models will swing back east all that much.

[Janie2006]

I think that watching individual model runs for long periods of time can lead one to miss the forest for the trees, so to speak. For example, one of the GFS ensembles has Irma heading straight into Panama City Beach. Frankly I'd be very surprised at that solution. The probability graphic is entirely reasonable given the synoptic set up as the week progresses.

[plasticup]

SENIOR DUTY METEOROLOGIST NWS ADMINISTRATIVE MESSAGE
NWS NCEP CENTRAL OPERATIONS COLLEGE PARK MD
0324Z MON SEP 04 2017

The 00Z GFS is running on time. In addition to the normal
complement of 00Z raobs...10 dropsonde observations were
available courtesy of NOAA Hurricane Hunter aircraft in the
vicinity of Irma.

Special 6-hourly soundings are requested from the following sites
starting at 18Z Monday: BIS, UNR, LBF, DDC, AMA, ABR, OAX, TOP,
OUN, INL, MPX, SGF, LZK, DVN, ILX, GRB, APX, DTX, ILN, OHX, and
SJU.

Handel/SDM/NCO/NCEP

4x daily balloon launches at most central US NWS offices starting this afternoon.

They really want to nail down this trough!

[blp]

SENIOR DUTY METEOROLOGIST NWS ADMINISTRATIVE MESSAGE
NWS NCEP CENTRAL OPERATIONS COLLEGE PARK MD
0324Z MON SEP 04 2017

The 00Z GFS is running on time. In addition to the normal
complement of 00Z raobs...10 dropsonde observations were
available courtesy of NOAA Hurricane Hunter aircraft in the
vicinity of Irma.

Special 6-hourly soundings are requested from the following sites
starting at 18Z Monday: BIS, UNR, LBF, DDC, AMA, ABR, OAX, TOP,
OUN, INL, MPX, SGF, LZK, DVN, ILX, GRB, APX, DTX, ILN, OHX, and
SJU.

Handel/SDM/NCO/NCEP

4x daily balloon launches at most central US NWS offices starting this afternoon.

Wow that looks to have made a huge difference.

[xironman]

SENIOR DUTY METEOROLOGIST NWS ADMINISTRATIVE MESSAGE
NWS NCEP CENTRAL OPERATIONS COLLEGE PARK MD
0324Z MON SEP 04 2017

The 00Z GFS is running on time. In addition to the normal
complement of 00Z raobs...10 dropsonde observations were
available courtesy of NOAA Hurricane Hunter aircraft in the
vicinity of Irma.

Special 6-hourly soundings are requested from the following sites
starting at 18Z Monday: BIS, UNR, LBF, DDC, AMA, ABR, OAX, TOP,
OUN, INL, MPX, SGF, LZK, DVN, ILX, GRB, APX, DTX, ILN, OHX, and
SJU.

Handel/SDM/NCO/NCEP

4x daily balloon launches at most central US NWS offices starting this afternoon.

They really want to nail down this trough!

Then they should do a sampling mission over the Pacific.

[forecasterjack]

If Irma can avoid the shredder, she'll have a very favorable environment for intensification near South Florida this weekend.
ECMWF PWAT free at weather.us https://weather.us/model-charts/euro/72 ... 1200z.html zero dry air

ECMWF deep layer shear, also free at weather.us https://weather.us/model-charts/euro/72 ... 1200z.html also zero (not including vortex where ULAC over LL cyclone creates shear)

[xironman]

What the hell happened overnight with the GFS and Euro? How did the Euro become the Eastern outlier?

That trough was always a borderline feature, just deep enough to pull Irma up. And now it misses.

Also, this is what happens when the hurricane hunters deploy: the models start to cluster once they have real data.

It doesn't miss. It blows a hole in the subtropical that allows the storm to take a hard right. Here is a time lapse showing the 588 line splitting

[Janie2006]

Yes, they are *very* interested in sampling.....from the New Orleans WFO:

The initial jet energy that causes the polar jet`s initial
descent toward the south is onshore over western Canada and is
being well sampled by the upper air network. The EURO wins on this
intialization with this portion of the jet as the sounding at
CYVQ shows an actual 55kt at 300mb while the EURO has 62kt and the
GFS 73kt. This seems to be a placement problem instead of a
strength issue. Although the jet energy that causes the polar jet
to dig more aggressively southward helping to maintain the deep
upper troughing over the eastern half of the CONUS is now south of
the Aleutians and is not being sampled. The tail end of this jet
was caught in the 12z 9/3 upper air analyses at PASY, but this is
not enough to lift any confidence levels to how deep and static
the upper trough will become. This will be the energy that tells
how long the trough will stand meridionally as the winds dive into
the west side of the trough maintaining its depth and placement
before lifing out. The next feature to look for will be a strong
short wave breaking away from the upper low near California and
moving northward over the extensive ridge on the west coast. This
short wave will finally dive into the deep south as well behind
and lateral to the strong jet core that moves through. And we
don`t have even one sample of this feature yet. We will get our
first sample of this on the Tuesday 12z or the Wednesday 00z upper
air run unless there is an 18z run over Washington state Tuesday
at KUIL or possibly CWLW in Canada. This feature is expected to be
responsible for maintaining some residual weak upper troughing
over the deep south. But nevertheless it is a strong short wave
feature that could have implications by next weekend into the new
week. This feature could enhance our mid to upper level northwest
flow next Monday. But again this is well off in the fcast.

Why copy-and-paste this? Well, things like this have to be taken into consideration as well, that is, large-scale synoptic patterns, when looking at storms like Irma and their eventual track.

[eastcoastFL]

Updated track map of Irma from the US Navy:

https://www.fnmoc.navy.mil/tcweb/cgi-bi ... 92W.INVEST,

All of South Florida in the cone now.

[toad strangler]

Updated track map of Irma from the US Navy:

https://www.fnmoc.navy.mil/tcweb/cgi-bi ... 92W.INVEST,

All of South Florida in the cone now.

So are areas S of Jamaica

[GCANE]

As it was for Harvey, so it appears to be for Irma.
Another perfect 355K PV forecast when Irma in the Straits of FL.

[meriland29]

Does anyone have a map of the mountainous range there? I know a lot of it is flat as well ..

[forecasterjack]

Thinking out loud. If that next wave in the C ATL can develop enough, could it deliver a blow to the WAR significant enough to let Irma come east? ECMWF H5 data free from weather.us: https://weather.us/model-charts/euro/72 ... 1200z.html can get vorticity, RH, winds, heights for all pressure levels via menus left of image

[birddogsc]

I thought I had read last night that the 0z GFS had some Gulfstream data in it for at least the ridging closer to the Islands. Could be wrong and forgive if so. The 0Z was rolling in so everyone was in hysterics then

If it did they collected it on the way down. The first mission that I can find departs Barbados (NOAA 49) at 1730Z today.

Just my opinion. But the models will change when more data can be inputed into models.Forgot the name of the plane that samples upper air patterns to its north and west. Cone will change. Just like it did last night.

Gulfstream G-IV - callsign, NOAA 49 - also known as Gonzo.

[sma10]

Almost all UKMET ensembles are taking Irma into Hispaniola and many of them move through the western Carribean south of Cuba. The SW trend continues...

There'd be almost no storm left by the time it reached Florida on that particular path. Runs the length of every island, including mountainous areas.

After following this storm with such passion and vigor this past week, its going to be very strange to many if the uk ensemble is correct. Because all of a sudden they may find themselves tracking a tropical wave by week's end.

[weatherwindow]

GFS 00z run in a nutshell: Donna with a twist of 1895

That was 1894(Sept 25).....agree with the Donna/1894 analogy WRT track...However if anything close to that presumed intensity verified, that would be a different universe for the Keys and KW...let's keep our fingers crossed....Rich

[curtadams]

What the hell happened overnight with the GFS and Euro? How did the Euro become the Eastern outlier?

It's not, really. The Euro ensemble remains, as usual, on the west side of guidance, with a lot of spread, also as usual, so some members are east of the overall consensus. The headline Euro is on the east side. Theoretically the headline run should be equivalent to another run of the ensemble, but only one, and so it can be an extreme one. Most likely, it just happened that the headline run was a very easterly one for the Euro. It's possible that the higher resolution of the headline actually changed the outcome but it seems unlikely with a mature formed storm. It would be a more plausible that the headline is "smarter" if we were dealing with cyclogenesis, because there the increased resolution might help, but we're not.

IMO the ensembles are better guidance than the headlines, partly because of the chance of any single run being an outlier, and partly because it gets your mind off extremely specific tracks so you can make better decisions. Looking at the headline of the GFS plowing down the center of FL might make you think about evacuating from one place to another in the peninsula, but looking at the Euro shows that almost no particular place anywhere in the peninsula is currently either at particularly high or low risk of a strike, and any evacuation decision now should be on site safety (away from the coast and especially the east coast, out of floodplains, wind-hardened buildings, etc.)

[invest man]

Just checked 12z consensus models. They look in line with NHC through their forecast period. However I'm beginning to disregard GFS in the longer range. Not suggesting it will be wrong in the end because even a blind squirt will catch a nut every now and then, but the Euro "seems" to be honing in on a solution but this again depends on trough and hp.

[Michele B]

:uarrow: so glad I live in West Central Florida!! may this pan out. sorry se coasters but Irma intent on you guys no matter what model we are looking at. but this would be very good for us over here and makes the most sense. right where I live thank goodness we don't get too much. our county spent millions on a deflector shield lol. Good thing too costing so much. They go south of us or north of us. Even Hermine didn't do much here in Hernando county. but like they say, it's not a matter of if but when.

Here a little bit of history "lore" here: "VERO Beach was named
That because it was believed that storms always "veered" around it!

I guess their luck finally ran out, too.