ATL: GERT - Post-Tropical - Discussion

Moderator: S2k Moderators

Message
Author
User avatar
wxman57
Moderator-Pro Met
Moderator-Pro Met
Posts: 22473
Age: 66
Joined: Sat Jun 21, 2003 8:06 pm
Location: Houston, TX (southwest)

Re: ATL: GERT - Hurricane - Discussion

#1501 Postby wxman57 » Wed Aug 16, 2017 10:44 am

Here's a comparison between Gert & Typhoon Banyan. Both, according to NOAA Dvorak estimates, are at T4.5, which equals approximately 75-80 kts. NHC went with 80 kts, but JMA went with 65 kts (10 min). JTWC went with 65 kts, too. It's clear from the comparison that these are not two equal storms Dvorak-wise.

Image
1 likes   

RL3AO
Moderator-Pro Met
Moderator-Pro Met
Posts: 16308
Joined: Thu Jun 14, 2007 10:03 pm
Location: NC

Re: ATL: GERT - Hurricane - Discussion

#1502 Postby RL3AO » Wed Aug 16, 2017 10:48 am

wxman57 wrote:Here's a comparison between Gert & Typhoon Banyan. Both, according to NOAA Dvorak estimates, are at T4.5, which equals approximately 75-80 kts. NHC went with 80 kts, but JMA went with 65 kts (10 min). JTWC went with 65 kts, too. It's clear from the comparison that these are not two equal storms Dvorak-wise.


I'd agree these look very different for being 4.5s.

Image
Image

But with Gert having warmer convection on the southern side, it makes them both LMG surrounding the center.
0 likes   

User avatar
Yellow Evan
Professional-Met
Professional-Met
Posts: 15948
Age: 25
Joined: Fri Jul 15, 2011 12:48 pm
Location: Henderson, Nevada/Honolulu, HI
Contact:

Re: ATL: GERT - Hurricane - Discussion

#1503 Postby Yellow Evan » Wed Aug 16, 2017 11:00 am

LG with no eye adjustment is T5.0, and in this case there is none since the eye isn't warm enough. But if this holds up, I expect T5.0 at 18z.
0 likes   

RL3AO
Moderator-Pro Met
Moderator-Pro Met
Posts: 16308
Joined: Thu Jun 14, 2007 10:03 pm
Location: NC

Re: ATL: GERT - Hurricane - Discussion

#1504 Postby RL3AO » Wed Aug 16, 2017 11:02 am

Yellow Evan wrote:LG with no eye adjustment is T5.0, and in this case there is none since the eye isn't warm enough. But if this holds up, I expect T5.0 at 18z.


Good point. WIth the eye popping out, it's easy to see why ADT is jumping up so quickly.
0 likes   

User avatar
wxman57
Moderator-Pro Met
Moderator-Pro Met
Posts: 22473
Age: 66
Joined: Sat Jun 21, 2003 8:06 pm
Location: Houston, TX (southwest)

Re: ATL: GERT - Hurricane - Discussion

#1505 Postby wxman57 » Wed Aug 16, 2017 11:23 am

Here's a shot from GOES-16. Eye better-defined:

Image
3 likes   

tolakram
Admin
Admin
Posts: 19138
Age: 60
Joined: Sun Aug 27, 2006 8:23 pm
Location: Florence, KY (name is Mark)

Re: ATL: GERT - Hurricane - Discussion

#1506 Postby tolakram » Wed Aug 16, 2017 12:00 pm

1 likes   
M a r k
- - - - -
Join us in chat: Storm2K Chatroom Invite. Android and IOS apps also available.

The posts in this forum are NOT official forecasts and should not be used as such. Posts are NOT endorsed by any professional institution or STORM2K.org. For official information and forecasts, please refer to NHC and NWS products.

tolakram
Admin
Admin
Posts: 19138
Age: 60
Joined: Sun Aug 27, 2006 8:23 pm
Location: Florence, KY (name is Mark)

Re: ATL: GERT - Hurricane - Discussion

#1507 Postby tolakram » Wed Aug 16, 2017 12:01 pm

Image
2 likes   
M a r k
- - - - -
Join us in chat: Storm2K Chatroom Invite. Android and IOS apps also available.

The posts in this forum are NOT official forecasts and should not be used as such. Posts are NOT endorsed by any professional institution or STORM2K.org. For official information and forecasts, please refer to NHC and NWS products.

User avatar
weathaguyry
Category 5
Category 5
Posts: 1272
Age: 20
Joined: Wed Jun 15, 2016 5:16 am
Location: Long Island, NY

Re: ATL: GERT - Hurricane - Discussion

#1508 Postby weathaguyry » Wed Aug 16, 2017 12:03 pm

:uarrow: Really cool looking eye!
0 likes   
My posts are only my opinions and NOT official forecasts. For official forecasts, consult the National Hurricane Center or the National Weather Service.

Irene 11', Sandy 12', Fay 20’, Isaias 20’, Elsa 21’, Henri 21’, Ida 21’

OntarioEggplant
Category 1
Category 1
Posts: 312
Joined: Sun Aug 07, 2016 11:16 am

Re: ATL: GERT - Hurricane - Discussion

#1509 Postby OntarioEggplant » Wed Aug 16, 2017 12:31 pm

I'm really disappointed that there is no recon in this. Could use it for the scientific aspect.
0 likes   

User avatar
EquusStorm
Category 5
Category 5
Posts: 1649
Age: 33
Joined: Thu Nov 07, 2013 1:04 pm
Location: Jasper, AL
Contact:

Re: ATL: GERT - Hurricane - Discussion

#1510 Postby EquusStorm » Wed Aug 16, 2017 12:38 pm

No way this isn't at least a little stronger than the current advisory intensity. I'm afraid this may go on the books as 10-15kts weaker than it actually might be between advisories, unless the 5pm bumps it up.
0 likes   
Colors of lost purpose on the canvas of irrelevance

Not a meteorologist, in fact more of an idiot than anything. You should probably check with the NHC or a local NWS office for official information.

User avatar
Emmett_Brown
Category 5
Category 5
Posts: 1343
Joined: Wed Aug 24, 2005 9:10 pm
Location: Sarasota FL

Re: ATL: GERT - Hurricane - Discussion

#1511 Postby Emmett_Brown » Wed Aug 16, 2017 12:48 pm

GO 99L GO!!!
2 likes   

User avatar
Kazmit
Category 5
Category 5
Posts: 1915
Age: 21
Joined: Mon Jul 25, 2016 8:49 am
Location: Williamsburg VA for college, Bermuda otherwise

Re: ATL: GERT - Hurricane - Discussion

#1512 Postby Kazmit » Wed Aug 16, 2017 1:10 pm

2 and a half hours until the 5pm advisory. It's really too bad that unless this holds its current form until then, it won't be acknowledged as at least a Cat 2.
0 likes   
Igor 2010, Sandy 2012, Fay 2014, Gonzalo 2014, Joaquin 2015, Nicole 2016, Humberto 2019

I am only a tropical weather enthusiast. My predictions are not official and may or may not be backed by sound meteorological data. For official information, please refer to the NHC and NWS products.

User avatar
Yellow Evan
Professional-Met
Professional-Met
Posts: 15948
Age: 25
Joined: Fri Jul 15, 2011 12:48 pm
Location: Henderson, Nevada/Honolulu, HI
Contact:

Re: ATL: GERT - Hurricane - Discussion

#1513 Postby Yellow Evan » Wed Aug 16, 2017 1:30 pm

Kazmit wrote:2 and a half hours until the 5pm advisory. It's really too bad that unless this holds its current form until then, it won't be acknowledged as at least a Cat 2.


16/1745 UTC 38.2N 64.1W T5.0/5.0 GERT -- Atlantic
0 likes   

CrazyC83
Professional-Met
Professional-Met
Posts: 33393
Joined: Tue Mar 07, 2006 11:57 pm
Location: Deep South, for the first time!

Re: ATL: GERT - Hurricane - Discussion

#1514 Postby CrazyC83 » Wed Aug 16, 2017 1:33 pm

ADT is T5.6 right now (105 kt). Based on all that data, I would probably go 95 kt.
0 likes   

User avatar
Cunxi Huang
Category 1
Category 1
Posts: 323
Age: 25
Joined: Thu Sep 26, 2013 12:17 pm
Location: San Luis Obispo, CA

Re: ATL: GERT - Hurricane - Discussion

#1515 Postby Cunxi Huang » Wed Aug 16, 2017 1:37 pm

I would say Gert is a top Cat 2 (95 kt) now, based on 100 kt from AMSU, 97 kt from SATCON, 104.5 kt from ADT, and T5.0/90 kt from SAB.

Image

CIMSS/NESDIS-USAF/NRL AMSU TC Intensity Estimation:
HURRICANE GERT
Wednesday 16aug17 Time: 1420 UTC
Latitude: 37.34 Longitude: -66.17
Storm position corresponds to AMSU-A FOV 15 [1<--->30]
-----------------------------------------------------------------
| Estimated MSLP: 968 hPa
| Estimated Maximum Sustained Wind: 100 kts
| Estimate Confidence: Good ( +/- 8mb +/- 9kts )
-----------------------------------------------------------------
Storm is sub-sampled: Bias correction applied is 0.0 hPa
Channel 8 (~150 hPa) Tb Anomaly: 1.68
Channel 7 (~250 hPa) Tb Anomaly: 1.84
Channel 6 (~350 hPa) Tb Anomaly: 0.49
RMW: 12 km
RMW Source is: MW
Environmental Pressure: 1012 (TPC)
Satellite: NOAA-90
ATCF data for Month: 08 Day: 16 Time (UTC): 1200

CURRENT ESTIMATE
Date (mmddhhmm): 08161420
SATCON: MSLP = 965 hPa MSW = 97 knots
SATCON Member Consensus: 98.0 knots
Pressure -> Wind Using SATCON MSLP: 89 knots
Distance to Outer Closed Isobar Used is 160 nm

TXNT21 KNES 161757
TCSNTL
A. 08L (GERT)
B. 16/1745Z
C. 38.2N
D. 64.1W
E. ONE/GOES-E
F. T5.0/5.0/D1.0/24HRS
G. IR/EIR/VIS
H. REMARKS...DT=5.0 BASED ON LG EMBEDDED GRAY SHADE WITH MG EYE
SURROUNDED BY BL. PT=5.0. MET=5.0. FT IS BASED ON DT.
SYSTEM HAS PEAKED AND NOW DECREASING.
I. ADDL POSITIONS
NIL
...SCHWARTZ
1 likes   
2006 SuTY SAOMAI | 2009 TY LINFA | 2010 TY FANAPI | 2010 SuTY MEGI | 2016 SuTY MERANTI | 2019 SuTY LEKIMA
DO NOT use my posts for life and death decisions. For official information, please refer to products from your RSMC and national weather agency.

CrazyC83
Professional-Met
Professional-Met
Posts: 33393
Joined: Tue Mar 07, 2006 11:57 pm
Location: Deep South, for the first time!

Re: ATL: GERT - Hurricane - Discussion

#1516 Postby CrazyC83 » Wed Aug 16, 2017 1:46 pm

AL, 08, 2017081618, , BEST, 0, 382N, 641W, 85, 970, HU, 34, NEQ, 90, 120, 80, 50, 1010, 160, 25, 0, 0, L, 0, , 0, 0, GERT, D, 0, , 0, 0, 0, 0, genesis-num, 014,

BT only raises it to 85 kt.
0 likes   

User avatar
Cunxi Huang
Category 1
Category 1
Posts: 323
Age: 25
Joined: Thu Sep 26, 2013 12:17 pm
Location: San Luis Obispo, CA

Re: ATL: GERT - Hurricane - Discussion

#1517 Postby Cunxi Huang » Wed Aug 16, 2017 1:50 pm

AL, 08, 201708161800, 10, DVTS, CI, , 3830N, 6410W, , 1, 77, 1, 979, 1, DVRK, , , , , , , , , , , , , , L, TAFB, MT, VI, 1, 4545 /////, , , GOES13, CSC, T, met = 5.0 and pat = 5.0

well the dvorak fix from NHC doesn't make any sense.
0 likes   
2006 SuTY SAOMAI | 2009 TY LINFA | 2010 TY FANAPI | 2010 SuTY MEGI | 2016 SuTY MERANTI | 2019 SuTY LEKIMA
DO NOT use my posts for life and death decisions. For official information, please refer to products from your RSMC and national weather agency.

User avatar
wxman57
Moderator-Pro Met
Moderator-Pro Met
Posts: 22473
Age: 66
Joined: Sat Jun 21, 2003 8:06 pm
Location: Houston, TX (southwest)

Re: ATL: GERT - Hurricane - Discussion

#1518 Postby wxman57 » Wed Aug 16, 2017 3:23 pm

Cunxi Huang wrote:AL, 08, 201708161800, 10, DVTS, CI, , 3830N, 6410W, , 1, 77, 1, 979, 1, DVRK, , , , , , , , , , , , , , L, TAFB, MT, VI, 1, 4545 /////, , , GOES13, CSC, T, met = 5.0 and pat = 5.0

well the dvorak fix from NHC doesn't make any sense.


It precisely matches their forecast, though. I've been saying for years that we should have a completely separate analysis/classification branch and a forecast branch. The forecasters then just deal with whatever the analysis branch classifies the storm as. By doing this, the verification could not be influenced by the forecast (I'm not saying that's happening). That would be interesting to observe. As a private forecaster, that's what we have to deal with. ;-)
2 likes   

User avatar
cycloneye
Admin
Admin
Posts: 138886
Age: 67
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: ATL: GERT - Hurricane - Discussion

#1519 Postby cycloneye » Wed Aug 16, 2017 3:35 pm

Up to Category 2

Hurricane Gert Discussion Number 16
NWS National Hurricane Center Miami FL AL082017
500 PM AST Wed Aug 16 2017

Cloud tops with temperatures colder than -65 deg C have wrapped
almost entirely around Gert's center, although eye temperatures
have been fluctuating all day. Dvorak intensity estimates vary
widely, from T4.5 from TAFB to around T5.5 from the UW-CIMSS ADT,
and since a warm eye has been unable to persist for an extended
period of time, the initial intensity is raised conservatively to
85 kt. This makes Gert the first category 2 hurricane of the
season. The window of opportunity for additional strengthening
appears to be closing. Gert will be moving over the colder waters
north of the Gulf Stream in about 12-18 hours, and southwesterly
shear will be increasing to well over 30 kt in about 12 hours.
Therefore, a fast weakening trend is forecast to begin on Thursday,
with Gert becoming a tropical storm by 36 hours. The FSU
phase-space diagrams indicate that Gert should be extratropical
just after 36 hours, and the GFS, ECMWF, and UKMET all have the
cyclone being absorbed by a larger extratropical low over the north
Atlantic by day 4.

Acceleration continues with the initial motion now 055/27 kt. With
Gert firmly embedded within the mid-latitude westerlies, the
hurricane's forward speed should increase for the next 24 hours,
followed by some deceleration as the cyclone begins to interact
with a large cut-off low moving east of Atlantic Canada. Most of
the track guidance is a little faster on this cycle, although the
ECMWF is significantly slower. The new NHC forecast is nudged a
little faster from 12-48 hours, but not too fast given the latest
ECMWF solution. The post-tropical portion of the track, intensity,
and wind radii forecasts incorporate guidance from NOAA's Ocean
Prediction Center.

Swells from Gert are affecting portions of the mid-Atlantic coast of
the United States, and are expected to spread northward to New
England and Atlantic Canada during the next day or two. These
swells are likely to produce dangerous surf and rip current
conditions. Please consult products from your local weather forecast
office for more information.

FORECAST POSITIONS AND MAX WINDS

INIT 16/2100Z 38.7N 62.4W 85 KT 100 MPH
12H 17/0600Z 40.7N 56.9W 85 KT 100 MPH
24H 17/1800Z 44.3N 48.2W 70 KT 80 MPH
36H 18/0600Z 48.3N 40.4W 55 KT 65 MPH
48H 18/1800Z 51.6N 35.7W 45 KT 50 MPH...POST-TROP/EXTRATROP
72H 19/1800Z 54.3N 32.6W 40 KT 45 MPH...POST-TROP/EXTRATROP
96H 20/1800Z...ABSORBED BY A LARGER EXTRATROPICAL LOW

$$
Forecaster Berg
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
Emmett_Brown
Category 5
Category 5
Posts: 1343
Joined: Wed Aug 24, 2005 9:10 pm
Location: Sarasota FL

Re: ATL: GERT - Hurricane - Discussion

#1520 Postby Emmett_Brown » Wed Aug 16, 2017 3:57 pm

Gert has the look of a low end Cat 3 on satellite.
1 likes   


Return to “2017”

Who is online

Users browsing this forum: No registered users and 27 guests