Major Hurricane Florence

[downeastnc]

2 hours ago, Hoosier said:

00z Euro appears to be headed right to NC.

I am still extremely skeptical of any solution showing landfall, or even skirting the coast, they just don't make it to the US when they are that far north that far east....that said the Euro track puts the center roughly 50-70 miles to my east as it crosses over the IBX of NC...starting to get into the 7 day range as well so its getting a lot of attention already but this is a rather hurricane savvy area...it really needs to start going W or even WSW very soon to be a threat....still there is quite a bit of model agreement for this to at least be a near miss.....

[Bhs1975]

Pretty much.... only a 700 mile spread between the GFS and UK.  The UK has a strong ridge that keeps Florence moving due west for much of the period.

Where did you get that map?


.

[Kmlwx]

1 minute ago, Bhs1975 said:

 

Where did you get that map?


.

 

Source is at the lower right hand side of the image. weathermodels.com

[Bhs1975]

Source is at the lower right hand side of the image. weathermodels.com

 

Yeah I saw it after I posted. Pay site

 

 

.

[olafminesaw]

Florence's structure appears to be rapidly deteriorating as of now. It will be interesting to see how quickly it recovers once it makes the turn more to the West and shear presumably relaxes.

[NJwx85]

 

[csnavywx]

GFS shows about 25 knots of effective shear right now (as of 12z). This stays fairly consistent through today and then begins to gradually decrease late tonight. 20 knots by tomorrow at this time and 15 by +36 hr. By +48 hr, forecast shear drops to or below about 10 knots. We can probably expect more weakening today before it begins to recover sometime late tomorrow. After tau 60 though, it gets into a pretty good environment, so another run at solid cat 4 status isn't out of the question.

The question is what happens with the track today and tomorrow.

[NJwx85]

6 minutes ago, csnavywx said:

GFS shows about 25 knots of effective shear right now (as of 12z). This stays fairly consistent through today and then begins to gradually decrease late tonight. 20 knots by tomorrow at this time and 15 by +36 hr. By +48 hr, forecast shear drops to or below about 10 knots. We can probably expect more weakening today before it begins to recover sometime late tomorrow. After tau 60 though, it gets into a pretty good environment, so another run at solid cat 4 status isn't out of the question.

The question is what happens with the track today and tomorrow.

This might be the most hostile environment Florence faces until she's well up into the Northern latitudes in about ten days. 

In any event, looks like shear might be decreasing just a hair to the South and West.

 

[Vice-Regent]

Already some evidence this morning that the ECMWF has a better handle on at least one crucial steering element compared to GFS. Southward sagging boundary aloft will put a cap on latitude gain tomorrow. ECMWF shows this feature well. GFS basically ignores it. Easy to spot on WV!

https://twitter.com/JackSillin/status/1037697861025234945

 

 

[yoda]

BULLETIN
Hurricane Florence Advisory Number  29
NWS National Hurricane Center Miami FL       AL062018
1100 AM AST Thu Sep 06 2018

...FLORENCE WEAKENS FURTHER...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...24.6N 48.6W
ABOUT 1030 MI...1660 KM ENE OF THE NORTHERN LEEWARD ISLANDS
ABOUT 1115 MI...1795 KM ESE OF BERMUDA
MAXIMUM SUSTAINED WINDS...105 MPH...165 KM/H
PRESENT MOVEMENT...NW OR 315 DEGREES AT 10 MPH...17 KM/H
MINIMUM CENTRAL PRESSURE...975 MB...28.80 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 1100 AM AST (1500 UTC), the center of Hurricane Florence was
located near latitude 24.6 North, longitude 48.6 West.  Florence is
moving toward the northwest near 10 mph (17 km/h).  A turn toward
the west-northwest and west with a decrease in forward speed is
expected through Saturday.  Florence may begin to move faster toward
the west-northwest over the western Atlantic early next week.

Maximum sustained winds have decreased to near 105 mph (165 km/h)
with higher gusts.  Additional weakening is forecast during the
next day or two.  However, Florence is expected to remain a
hurricane and likely reintensify over the weekend.

Hurricane-force winds extend outward up to 15 miles (30 km) from the
center, and tropical-storm-force winds extend outward up to 90 miles
(150 km).

The estimated minimum central pressure is 975 mb (28.80 inches).


HAZARDS AFFECTING LAND
----------------------
SURF:  Swells generated by Florence will begin to affect Bermuda on
Friday and will reach portions of the U.S. East Coast over the
weekend.  These swells are likely to cause life-threatening surf and
rip current conditions.  Please consult products from your local
weather office.

[yoda]

Hurricane Florence Discussion Number  29
NWS National Hurricane Center Miami FL       AL062018
1100 AM AST Thu Sep 06 2018

Vertical shear has increased since yesterday, which has caused a
degradation of Florence's structure and a decrease in its maximum
winds.  The cloud-filled eye has been eroded over the past hour or
so, and the deep convection is no longer symmetric, with the
low-level circulation peeking out from under the higher clouds.
Dvorak CI numbers from TAFB and SAB have fallen to T5.0-5.5 (90-100
kt), while the objective numbers from UW-CIMSS support 70-90 kt.
The initial intensity is set at 90 kt, near the middle of this wide
range of estimates.

The intensity forecast has been somewhat of a self-defeating
prophecy due to the nuances of the environmental shear.  Even though
Florence was able to rapidly intensify yesterday in an area just
south of a zone of strong shear, the hurricane's stronger-than-
expected intensity caused it to move more poleward, into that
stronger shear.  Right now, shear analyses range anywhere from
25-30 kt, and the latest available guidance suggests that this
level of shear should continue for another 12-24 hours.  As a
result, continued weakening is forecast over the next day or so.
After 36 hours, Florence is likely to encounter an upper-level
environment that is more conducive for reintensification.  The NHC
forecast is adjusted downward toward the newest consensus aids,
especially during the first 48 hours, but it still shows Florence
reaching major hurricane strength again by days 4 and 5.

Florence's forward motion has slowed just a little to 9 kt toward
the northwest (315 degrees).  A mid-level ridge is building to the
north, which is likely to cause the hurricane to turn westward by
36 hours, with that motion continuing through about day 3.  After
that time, there is still considerable uncertainty in the evolution
of the steering pattern over the western Atlantic, especially on day
4.  On one hand, the GFS and HWRF dig a strong shortwave trough over
Atlantic Canada by Monday, creating a break in the ridge which would
allow Florence to turn northwestward.  On the other hand, the ECMWF
and UKMET both have weaker troughs and maintain stronger ridging
over the northwestern Atlantic, allowing Florence to maintain a
westward or west-northwestward course.  All the models show a
mid-level high over the western Atlantic by Tuesday.  Due to typical
biases among these models in the part of the Atlantic, we prefer to
be between the GFS and ECMWF solutions at this time, which places
the official NHC track forecast close to the TVCN multi-model
consensus and just north of HCCA.

There is still considerable model ensemble spread for Florence's
track beyond day 5.  Given the large uncertainty at these time
ranges, it is far too soon to speculate what, if any, impacts
Florence may have on the U.S. East Coast next week.  Regardless of
Florence's eventual track, large swells emanating from the hurricane
will reach Bermuda beginning on Friday and portions of the U.S. East
Coast this weekend, resulting in life-threatening surf and rip
currents.

FORECAST POSITIONS AND MAX WINDS

INIT  06/1500Z 24.6N  48.6W   90 KT 105 MPH
 12H  07/0000Z 25.2N  49.8W   80 KT  90 MPH
 24H  07/1200Z 25.6N  51.3W   75 KT  85 MPH
 36H  08/0000Z 25.6N  52.6W   75 KT  85 MPH
 48H  08/1200Z 25.7N  54.0W   80 KT  90 MPH
 72H  09/1200Z 26.3N  56.4W   90 KT 105 MPH
 96H  10/1200Z 28.0N  59.5W  100 KT 115 MPH
120H  11/1200Z 29.5N  65.0W  105 KT 120 MPH

$$
Forecaster Berg

[olafminesaw]

Edit: I found it.

The NHC cone put's it around a 5% chance.

[olafminesaw]

As we watch 12z , one thing to watch is the GFS has shown huge gains in lattitude between Sunday morning and Monday night. If it ends up being a more WNW movement, an impact to the east coast is a lot more likely.

[Hoth]

Perhaps a trick of the eye, but appears Florence has begun a leftward jog?

[TriPol]

Oh no...

[olafminesaw]

Looks like the GFS might smash it into long island.

[yoda]

9 minutes ago, olafminesaw said:

Looks like the GFS might smash it into long island.

Just hits on the eastern end of LI... also looks like a Nantucket smash

[Gravity Wave]

12z GGEM virtually identical to 0z.

[yoda]

1 minute ago, Gravity Wave said:

12z GGEM virtually identical to 0z.

Yup... ILM or just north of there landfall at 180

[yoda]

12z UKIE at 144

 

[JakkelWx]

12z GFS for LI... Man. 

[Gravity Wave]

FWIW, the ICON looks like the GGEM/Euro. I have no clue how it performs with tropical systems, however.

[olafminesaw]

I remember the GFS had Irma several runs in a row hitting NY/New England. Fun times.

[TriPol]

There's a 1025 High up in Canada... how is Florence just moving north like this at hour 180?

[jpeters3]

4 minutes ago, TriPol said:

There's a 1025 High up in Canada... how is Florence just moving north like this at hour 180?

Looks like it approaches the eastern periphery of a relatively weak upper-level trough at that point.

[bobbutts]

8 minutes ago, Jakkel138 said:

12z GFS for LI... Man. 

Post the 162hr of the same product.. Quite a bit of weakening occurs between 162-192

Man if we can get a storm that healthy anywhere near those coordinates the E. Coast will be freaking out.

[olafminesaw]

5 minutes ago, TriPol said:

There's a 1025 High up in Canada... how is Florence just moving north like this at hour 180?

[TriPol]

1 minute ago, olafminesaw said:

I remember the GFS had Irma several runs in a row hitting NY/New England. Fun times.

Completely different setup and storm. There have been a few threats since Sandy and Irene to the NYC area. Andrea (2013) was the last one that brought any kind of moisture with it.

[JovialWeather]

Watching what the GFS does to this thing after running into that high is somewhat fascinating.

[jpeters3]

Everyone has to remember that surface flow is not the only steering current acting on TCs, especially in the mid-latitudes.  Upper level flow is southerly in the run prior to 180h, which will send the system north.