ATL: HERMINE - Models

[Steve]

12Z UKMET track:

https://s11.postimg.org/9t5zc2lcz/ukm2_ ... _gentr.png

Split energy? I really don't see anything else in the atmosphere (short of a chance that a piece of Fiona flies down ahead of 99L) that could give rise to another storm in the Western Gulf unless a decoupled piece of 99L continues west and finds a spot it can intensify in. Though UK Met hasn't been the only model to show some type of moderate development in the Western Gulf.

[cycloneye]

Hopefully,this mission feed good data to the models.

 https://twitter.com/NOAA_HurrHunter/status/768538205922725889

[sfwx]

( Interesting model discussion today)

Area Forecast Discussion
National Weather Service Melbourne FL
335 PM EDT WED AUG 24 2016

.DISCUSSION...


EXTENDED...(modified prev disc)
Tropical wave Invest 99L over the NE Carib will maintain a high
level of uncertainty in the fcst. Global models suggest a favorable
environment for intensification as the system moves closer to the
Bahamas; however, dry air and its proximity to the hilly terrain of
Puerto Rico, the Dominican Republic, and Haiti will remain limiting
factors over the next 24-48 hours.

Latest guidance continues to support a strong ridge east of the MS
river valley that should prevent the a developing low from recurving
into the open Atlantic east of the Peninsula. Even so...the 24/12Z
GFS model now suggests a weak H100-H70 circulation center transiting
the Bahama Bank btwn 12Z Sat-12Z Mon...then hugging the east FL
coast thru 12Z Wed. The 24/12Z ECMWF model on the other hand dvlps a
well defined circulation over the central Bahamas by 12Z Sat... then
carries it acrs the south FL peninsula thru 12Z Mon and up the west
FL coast into the Big Bend area thru 12Z Wed.

The bottom line is: with a continued west-northwest motion expected
for the next several days, it is recommended that both residents and
visitors to Florida remain abreast of the latest forecasts from
local National Weather Service Forecast Offices and the National
Hurricane Center.

.MARINE...


Weekend...(modified prev disc)
Forecast uncertainty remains high due to the track and development
of Invest 99L. GFS/ECMWF models both bring an area of low pressure
across the Bahamas on Saturday and the south half of the FL
peninsula on Sunday/Monday but differ greatly with respect
intensity, speed, and organization. ECMWF is the faster and more
aggressive model, GFS is slower and more disorganized. Both model
tracks diverge significantly aft 00Z Sun with GFS taking the system
up the east FL coast...ECMWF up the west FL coast. In either
case...high pressure ridge over the mid Atlantic will likely combine
with whatever low pressure area forms to generate a tight pgrad acrs
the lcl Atlc...resulting in rough/hazardous boating conds this
weekend. Mariners are urged to remain alert to this potential.


Public/Marine Wx.....Bragaw
Aviation/Impact Wx...Johnson

[PTrackerLA]

This falls under opinion but to me the UKMet is not a very reliable model and/or shows a lot of phantom spin ups. Remember the nearly cat 3 it was showing from the "great flood low" in the gulf a few weeks ago? Here we are again with UKMet shifting towards the GFS and some spurious WGOM development. It's more inconsistent than GFS and EURO IMO.

[PTrackerLA]

Watching the 12z Euro ensembles come in on weatherbell, FWIW out to 6 days a majority are still out in the central Gulf like the 00z. There is more spread though with members extending eastward through the Peninsula and right off the east coast of Florida.

[gatorcane]

One thing is for sure, these models haven't budged much from some kind of South Florida impact, despite some of the larger variations when you get out beyond 5 days:

[La Breeze]

This falls under opinion but to me the UKMet is not a very reliable model and/or shows a lot of phantom spin ups. Remember the nearly cat 3 it was showing from the "great flood low" in the gulf a few weeks ago? Here we are again with UKMet shifting towards the GFS and some spurious WGOM development. It's more inconsistent than GFS and EURO IMO.

PT, we surely do not need this in our neighborhood - no one does, but right now we are already wiped out. Stay safe, PT and others.

[gatorcane]

What I think is giving the models fits on how strong this could get in the Bahamas on the approach to Florida is a ULL that "pinches" off from the NE. In the 12Z NAM it was weak and basically non-existent. The 12Z NAM had a stronger depiction of 99L. In the 18Z NAM, the ULL is further SW and more pronounced, inducing shear on 99L. Look to the north of 99L in that image below which is the latest 18Z run in progress:

[Alyono]

NAM shifted west. It also dropped the second Gulf system

This is why I call BS on the east shift at 12Z. It spins up a Gulf TD/TS from the storms currently over Florida. That was total BS as the precip pattern now is nowhere near as organized as the models indicated

[Nederlander]

This falls under opinion but to me the UKMet is not a very reliable model and/or shows a lot of phantom spin ups. Remember the nearly cat 3 it was showing from the "great flood low" in the gulf a few weeks ago? Here we are again with UKMet shifting towards the GFS and some spurious WGOM development. It's more inconsistent than GFS and EURO IMO.

Agree for the most part, but you have to admit that had that system been offshore a couple hundred miles, who knows what it could have become..

Can someone post the ECMWF ensembles when they are available please?

[gatorcane]

18Z NAM is still coming in pretty strong though, 75 hours below with the system possibly slowing and possibly making a turn.

[gatorcane]

Here is how the 18Z NAM ends with the system still moving slowly NW and intensifying, you would think some kind of west or WNW turn with the ridge over the Carolinas if the run went out farther.

[stormlover2013]

from the khou forum from a pro

updated Weather Prediction Center Day 3 to 7 surface charts suggests the surface reflection of potential Hermine will be South of Louisiana next week. I see no reason to dismiss a potential Gulf of Mexico scenario regardless of the daily shifts of the operational guidance. The SE Ridge has been very strong all late Spring into Summer. I see no significant changes via the ensembles that the persistent SE United States/Bermuda Ridge will quickly disappear.

Once we get additional synoptic data from the Global Hawk ingested into the Global computer guidance and actual Tropical Cyclone Genesis occurs, expect swings in the computer models.

[jasons2k]

from the khou forum from a pro

updated Weather Prediction Center Day 3 to 7 surface charts suggests the surface reflection of potential Hermine will be South of Louisiana next week. I see no reason to dismiss a potential Gulf of Mexico scenario regardless of the daily shifts of the operational guidance. The SE Ridge has been very strong all late Spring into Summer. I see no significant changes via the ensembles that the persistent SE United States/Bermuda Ridge will quickly disappear.

Once we get additional synoptic data from the Global Hawk ingested into the Global computer guidance and actual Tropical Cyclone Genesis occurs, expect swings in the computer models.

With all due respect, Srain is not a professional meteorologist. That said, I do highly respect his analysis.

[ronyan]

18z GFS...going through the FL straights.
http://www.tropicaltidbits.com/analysis ... 0&ypos=376

[Alyono]

not sure the MU will even intensify this in the Gulf. It has the system under convergent upper flow aloft

[Bocadude85]

18z GFS...going through the FL straights.
http://www.tropicaltidbits.com/analysis ... 0&ypos=376

The strongest vortex actually moves through extreme sfla similar to the 12z euro it's just weaker then the euro

[PTrackerLA]

not sure the MU will even intensify this in the Gulf. It has the system under convergent upper flow aloft

GFS with another sleeper run and now shows unfavorable conditions in the gulf? Guess we will see if there's any change to the HWRF. At this point, all I know is I know nothing.

[Alyono]

not sure the MU will even intensify this in the Gulf. It has the system under convergent upper flow aloft

GFS with another sleeper run and now shows unfavorable conditions in the gulf? Guess we will see if there's any change to the HWRF. At this point, all I know is I know nothing.

yep, shows the weak surface trough dissipating under unfavorable conditions in the Gulf. This is the first model that I have seen that has shown unfavorable conditions in the Gulf. Something to monitor

[tolakram]

The GFS has been too consistent to ignore IMO. It's not as good as the euro, but it's also not that bad. It may be processing something that the euro isn't. Maybe that bit of info is rarely important but this time around it is. There's a LOT of data that these models need to process.