ATL: DORIAN - Post-Tropical - Discussion

[gatorcane]

Latest SHIPS output showing not quite as bad shear as what it was showing yesterday. SSTs dip to marginal at hours 36 to 48 then look how they go up after that.

* ATLANTIC SHIPS INTENSITY FORECAST *
* GOES PROXY USED, OHC AVAILABLE *
* INVEST AL982013 07/23/13 18 UTC *

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 25 27 29 32 36 43 48 53 55 56 58 60 61
V (KT) LAND 25 27 29 32 36 43 48 53 55 56 58 60 61
V (KT) LGE mod 25 26 27 29 32 39 46 52 56 58 60 64 67
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 12 10 11 11 8 2 3 10 10 12 10 15 20
SHEAR ADJ (KT) -2 -4 -6 -4 -3 0 0 0 0 0 0 -1 4
SHEAR DIR 70 59 54 38 39 228 280 241 248 255 252 244 221
SST (C) 26.6 26.7 26.8 26.8 26.4 25.4 25.8 26.4 27.0 27.4 27.8 28.1 28.0
POT. INT. (KT) 121 123 124 125 121 112 116 121 128 131 136 141 140
ADJ. POT. INT. 119 123 126 127 122 112 116 122 128 129 134 141 139
200 MB T (C) -53.7 -53.8 -54.1 -54.0 -54.0 -54.5 -54.3 -54.3 -54.2 -54.5 -54.5 -54.6 -54.5
TH_E DEV (C) 4 4 5 5 5 5 6 7 8 9 10 11 12
700-500 MB RH 72 74 74 73 74 76 69 63 54 52 47 46 47
GFS VTEX (KT) 8 7 7 8 8 9 9 8 8 7 7 7 7
850 MB ENV VOR 19 14 16 22 31 26 27 21 4 0 -8 -4 -15
200 MB DIV 24 13 -3 -2 9 13 20 7 6 0 4 30 22
700-850 TADV 2 0 -3 -4 -2 -1 0 6 7 6 -3 -2 -5
LAND (KM) 725 868 1017 1192 1373 1783 1919 1685 1525 1399 1137 876 485
LAT (DEG N) 12.3 xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x
LONG(DEG W) 23.7 xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x
STM SPEED (KT) 12 15 16 18 19 20 21 21 19 17 17 19 19
HEAT CONTENT 9 2 0 0 0 0 0 0 4 5 9 25 22

FORECAST TRACK FROM OFPI INITIAL HEADING/SPEED (DEG/KT):275/ 10 CX,CY: -9/ 1
T-12 MAX WIND: 25 PRESSURE OF STEERING LEVEL (MB): 595 (MEAN=623)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 17.1 (MEAN=14.5)
% GOES IR PIXELS WITH T < -20 C 50-200 KM RAD: 49.0 (MEAN=65.0)

INDIVIDUAL CONTRIBUTIONS TO INTENSITY CHANGE
6 12 18 24 36 48 60 72 84 96 108 120
----------------------------------------------------------
SAMPLE MEAN CHANGE 1. 2. 3. 4. 6. 8. 9. 11. 12. 12. 13. 14.
SST POTENTIAL 0. 1. 1. 2. 5. 10. 16. 21. 25. 28. 30. 31.
VERTICAL SHEAR MAG 1. 2. 3. 4. 7. 9. 10. 10. 10. 10. 9. 7.
VERTICAL SHEAR ADJ 0. 1. 1. 1. 1. 2. 2. 2. 1. 1. 1. 1.
VERTICAL SHEAR DIR 1. 2. 3. 4. 5. 4. 3. 1. -1. -2. -4. -6.
PERSISTENCE 0. -1. -1. -1. -1. -1. -1. -1. 0. 0. 0. 0.
200/250 MB TEMP. 0. 0. 0. 1. 1. 2. 3. 3. 4. 5. 6. 8.
THETA_E EXCESS 0. -1. -2. -3. -4. -6. -7. -9. -10. -10. -10. -10.
700-500 MB RH 0. 0. 0. -1. -1. -2. -2. -2. -2. -2. -2. -1.
GFS VORTEX TENDENCY 0. -1. 0. 0. 0. -1. -1. -2. -3. -4. -3. -4.
850 MB ENV VORTICITY 0. 0. 0. 0. 0. 0. 0. 0. -1. -1. -1. -2.
200 MB DIVERGENCE 0. 0. 0. -1. -1. -1. -1. -1. -1. -1. -1. -1.
850-700 T ADVEC 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
ZONAL STORM MOTION 0. 0. 0. 1. 1. 1. 1. 2. 2. 2. 2. 2.
STEERING LEVEL PRES 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
DAYS FROM CLIM. PEAK 0. 0. 0. 0. 0. -1. -1. -1. -1. -1. -1. -1.
GOES PREDICTORS 0. 0. 0. -1. -1. -2. -3. -3. -4. -4. -3. -3.
OCEAN HEAT CONTENT 0. 0. 0. 0. 0. -1. -1. -1. -1. -1. -1. -1.
----------------------------------------------------------
TOTAL CHANGE 2. 4. 7. 11. 18. 23. 28. 30. 31. 33. 35. 36.

** 2011 ATLANTIC RI INDEX AL982013 INVEST 07/23/13 18 UTC **

12 HR PERSISTENCE (KT): 0.0 Range:-45.0 to 30.0 Scaled/Wgted Val: 0.6/ 2.0
850-200 MB SHEAR (KT) : 10.4 Range: 26.2 to 3.2 Scaled/Wgted Val: 0.7/ 1.3
STD DEV OF IR BR TEMP : 999.0 Range: 34.1 to 3.2 Scaled/Wgted Val:999.0/999.0
D200 (10**7s-1) : 8.2 Range:-21.0 to 165.0 Scaled/Wgted Val: 0.2/ 0.3
POT = MPI-VMAX (KT) : 98.2 Range: 33.8 to 126.5 Scaled/Wgted Val: 0.7/ 0.8
850-700 MB REL HUM (%): 75.2 Range: 56.0 to 85.0 Scaled/Wgted Val: 0.7/ 0.4
Heat content (KJ/cm2) : 2.2 Range: 0.0 to 130.0 Scaled/Wgted Val: 0.0/ 0.0
% area w/pixels <-30 C: 999.0 Range: 17.0 to 100.0 Scaled/Wgted Val:999.0/999.0

Prob of RI for 25 kt RI threshold= 999% is 999.0 times the sample mean(12.8%)
Prob of RI for 30 kt RI threshold= 999% is 999.0 times the sample mean( 8.4%)
Prob of RI for 35 kt RI threshold= 999% is 999.0 times the sample mean( 5.0%)
Prob of RI for 40 kt RI threshold= 999% is 999.0 times the sample mean( 3.4%)

** PROBLTY OF AT LEAST 1 SCNDRY EYEWL FORMTN EVENT AL982013 INVEST 07/23/2013 18 UTC **
TIME(HR) 0-12 12-24(0-24) 24-36(0-36) 36-48(0-48)
CLIMO(%) 0 0( 0) 0( 0) 0( 0) <-- PROB BASED ON INTENSITY ONLY
PROB(%) 0 0( 0) 0( 0) 0( 0) PC4 UNAVAIL...MODEL SKILL DEGRADED

ftp://ftp.nhc.noaa.gov/atcf/stext/13072 ... _ships.txt

[cycloneye]

Looking at the latest SHIPS model guidance, it looks like it is seeing a little bit less shear over the coming days than what it was showing yesterday. I posted this in the models thread.

Now up to 61kts in 120 hours.

V (KT) NO LAND 25 27 29 32 36 43 48 53 55 56 58 60 61

ftp://ftp.nhc.noaa.gov/atcf/stext/13072 ... _ships.txt

This means conditions may be more favorable than first thought down the road.

[Blown Away]

Still showing shear on upward trend towards 120 hours...

[blp]

The 12z HWRF does not kill it off and has it a tad bit stronger at the end of the run than the 00z run.

http://moe.met.fsu.edu/cgi-bin/hwrftc2.cgi?time=2013072312-invest98l&field=Sea+Level+Pressure&hour=Animation

[wxman57]

Remember, SHIPS is a statistical intensity forecast model. For disturbances, it often is way too strong. In the case of 98L, it almost qualifies for a TD. Circulation isn't too bad but convection is being sheared off to the WSW. It will continue to fight a battle with a little shear and with cooler SSTs added in by tomorrow. If the shear drops off just a bit and if convection builds back over the center, then it should be upgraded.

[cycloneye]

The 18z guidance has shifted south.

[Ivanhater]

Code red

[Blown Away]

Looking at the latest SHIPS model guidance, it looks like it is seeing a little bit less shear over the coming days than what it was showing yesterday. I posted this in the models thread.

Now up to 61kts in 120 hours.
V (KT) NO LAND 25 27 29 32 36 43 48 53 55 56 58 60 61

ftp://ftp.nhc.noaa.gov/atcf/stext/13072 ... _ships.txt

This means conditions may be more favorable than first thought down the road.

18 z

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 25 27 29 31 34 39 41 42 41 41 42 44 45

12z

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 25 27 29 32 34 39 42 43 42 42 43 44 45

06z

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 25 29 33 37 42 49 51 52 50 47 44 42 41

00z

[Ivanhater]

Looks quite good

[beoumont]

A SURFACE LOW PRESSURE SYSTEM LOCATED A COUPLE OF HUNDRED MILES
SOUTH OF THE CAPE VERDE ISLANDS IS MOVING WESTWARD AT ABOUT 10 MPH.
THIS SYSTEM HAS A WELL-DEFINED CIRCULATION..

FORECASTER STEWART

A 1011-1012 mb. surface low (maaaaaybe 1010), with 1012mb pressure at SAL in the Cape Verde's; with 15 knt. winds near the center and a ship 120 miles from the center in a thunderstorm with a gust of 25 knts. Looks kinda pretty.

[CrazyC83]

Is it just me, or am I get flashbacks to what would be the name that Dorian replaced?

[cycloneye]

Afternoon Marine Discussion by NHC


LOW PRES IN EASTERN ATLC UNDER FAVORABLE CONDITIONS FOR FURTHER
TROPICAL DEVELOPMENT...EXPECTED TO STRENGTHEN TO TROPICAL STORM
THU THROUGH FRI...BUT THEN ENTER REGION OF ADVERSE CONDITIONS.
EITHER WAY IT IS BOUND TO WEAKEN ATLC RIDGE N OF CARIBBEAN
DIMINISH WINDS FOR THIS WEEKEND.

http://www.nhc.noaa.gov/text/MIAMIMATS.shtml

[hurricanekid416]

Is there a chance of redevelopment in the western atlantic after it gets sheared apart

[Hurricane_Luis]

Is it just me, or am I get flashbacks to what would be the name that Dorian replaced?

Hurricane Dean was a Cat 5 storm, This probably won't even be close to that intensity.

[Blown Away]

18z...Big shift S in TVCN...Wonder if the intensity models continue going up if 98L goes farther S??

[Senobia]

Code red

Does it happen often that a system that newly off Africa has such high chances of development? Haven't paid attention to the models and such until this year so I don't have anything to compare it to.

On a side note, Eric Berger (Science Blogger, not a pro-met, from a Houston newspaper) gives a conflicting outlook on 98L: (I don't know how to link text: http://www.beaumontenterprise.com/news/ ... 681823.php)

In other words, although it's certainly possible, this system appears unlikely to affect the Gulf of Mexico.

The possible formation of this storm, dubbed Invest 98L, signals the beginning of the "Cape Verde" hurricane season, so named for storms that develop near the Cape Verde islands, off the west coast of Africa.

Storms that form in this region and track westward across the Atlantic Ocean are often the most powerful and dangerous storms that form in a given hurricane season. The two most destructive hurricanes to have hit the upper Texas coast, Hurricane Ike in 2008 and the Great Storm of 1900, were both Cape Verde hurricanes.

First he's very, "Meh - don't worry about it. It won't make it into the Gulf" and then likens it to two of the worst storms Texas has ever seen.

[blp]

I think I finally see it on the Euro in the low resolution images under a ridge. I wish I had better resolution. It then recurves it out to sea. It seems to be the northern outlier now.

[Blown Away]

WPC has our low just north of PR in 6 days then moves WNW into SE Bahamas at day 7...Notice ridge building W day 6/7 (open link)
http://www.hpc.ncep.noaa.gov/medr/day6nav_color.html

[gatorcane]

I think I finally see it on the Euro in the low resolution images under a ridge. I wish I had better resolution. It then recurves it out to sea. It seems to be the northern outlier now.

Here is the 144 hour 12Z ECMWF position for 98L which is a northern outlier right now (it's the orange blob north of the Leewards around 30N, 60W).

Also the ECMWF is now showing a vorticity maintaining (albeit weak) throughout the run (it's not killing off 98L in a few days like it was in the 00Z though the 00Z did bring 98L back after 5 days):

[HurricaneMaster_PR]

NHC 72 hrs Surface Forecast



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