ATL: DORIAN - Post-Tropical - Discussion

[Gustywind]

Is that the WNW (tendency?) or why not NW direction the NHC is mentionning?

Here is the latest from SSD.


23/2345 UTC 13.4N 25.5W T1.0/1.0 98L
23/1745 UTC 12.3N 23.7W T1.0/1.0 98L

[ozonepete]

8 PM discussion. Notice that the latest TWD says that the direction is west ... while the latest TWO says moving WEST-NORTHWESTWARD. Find the error . Anyone notice that.

000
AXNT20 KNHC 240004
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE JUL 23 2013

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURE...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 23W/24W TO THE SOUTH OF
16N. A 1008 MB LOW PRESSURE CENTER IS ALONG THE WAVE NEAR 12N.
THE FEATURE IS MOVING WESTWARD 10 KNOTS. A MIDDLE LEVEL TO UPPER
LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 16N39W. THIS CYCLONIC
CENTER IS SURROUNDED BY COMPARATIVELY DRIER AIR IN SUBSIDENCE...
ON WATER VAPOR IMAGERY. CONVECTIVE PRECIPITATION...SCATTERED
STRONG FROM 11N TO 13N BETWEEN 25W AND 27W. ENVIRONMENTAL
CONDITIONS ARE EXPECTED TO BE FAVORABLE FOR DEVELOPMENT DURING
THE NEXT DAY OR SO...BEFORE UPPER LEVEL WINDS AND OCEAN
TEMPERATURES BECOME LESS CONDUCIVE BY THURSDAY.
THIS SYSTEM HAS A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48
HOURS.

Good catch, Gusty. They need to fix this. 20 mph seems maybe a little too fast and 10 knots sounds too slow...

[Gustywind]

8 PM discussion. Notice that the latest TWD says that the direction is west ... while the latest TWO says moving WEST-NORTHWESTWARD. Find the error . Anyone notice that.

000
AXNT20 KNHC 240004
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE JUL 23 2013

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURE...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 23W/24W TO THE SOUTH OF
16N. A 1008 MB LOW PRESSURE CENTER IS ALONG THE WAVE NEAR 12N.
THE FEATURE IS MOVING WESTWARD 10 KNOTS. A MIDDLE LEVEL TO UPPER
LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 16N39W. THIS CYCLONIC
CENTER IS SURROUNDED BY COMPARATIVELY DRIER AIR IN SUBSIDENCE...
ON WATER VAPOR IMAGERY. CONVECTIVE PRECIPITATION...SCATTERED
STRONG FROM 11N TO 13N BETWEEN 25W AND 27W. ENVIRONMENTAL
CONDITIONS ARE EXPECTED TO BE FAVORABLE FOR DEVELOPMENT DURING
THE NEXT DAY OR SO...BEFORE UPPER LEVEL WINDS AND OCEAN
TEMPERATURES BECOME LESS CONDUCIVE BY THURSDAY.
THIS SYSTEM HAS A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48
HOURS.

Good catch, Gusty. They need to fix this. 20 mph seems maybe a little too fast and 10 knots sounds too slow...

thanks Pete. You're right. Some adjustements should come from that, i suppose. Anyway 98L is moving somewhere ...

[cycloneye]

00z Best Track.Moving WNW 285 degrees at 13kts.

AL, 98, 2013072400, , BEST, 0, 133N, 256W, 25, 1008, LO

LATCUR = 13.3N LONCUR = 25.6W DIRCUR = 285DEG SPDCUR = 13KT

[Aric Dunn]

Convection is concentrating near the center now. Could be upgraded at any time.

yeah convection although limited is firing now right over the center.

[RL3AO]

This is so bad from The Weather Channel.

http://www.weather.com/video/tropical-update-6584

Watch to about 1:35. The map shows SSTs in the "60's", where in reality they are around 24C at the lowest (75 degrees).

[Caribwxgirl]

So is it moving w or wnw? NHC is confusing me at the mo.

[cycloneye]

Video by Levi Cowan about 98L.

http://www.tropicaltidbits.com/blog/201 ... from-land/

[Gustywind]

00z Best Track.Moving WNW 285 degrees at 13kts.

AL, 98, 2013072400, , BEST, 0, 133N, 256W, 25, 1008, LO

LATCUR = 13.3N LONCUR = 25.6W DIRCUR = 285DEG SPDCUR = 13KT

Interresting Cycloneye as SSD numbers are close to these coordinates :
23/2345 UTC 13.4N 25.5W T1.0/1.0 98L

[cycloneye]

So is it moving w or wnw? NHC is confusing me at the mo.

Moving WNW at 285 degrees.

LATCUR = 13.3N LONCUR = 25.6W DIRCUR = 285DEG SPDCUR = 13KT

[Caribwxgirl]

So is it moving w or wnw? NHC is confusing me at the mo.

Moving WNW at 285 degrees.

LATCUR = 13.3N LONCUR = 25.6W DIRCUR = 285DEG SPDCUR = 13KT

Thanks

[Hurricane Alexis]

Looks like an Ike/France's type tracks here being portrayed by some models

According to what? Do you have historical data you can post?

Uploaded with ImageShack.us



Uploaded with ImageShack.us

The models have 98L moving generally westward similar to those two.

[Blown Away]

Levi Cowan's prediction...
http://www.tropicaltidbits.com

[Gustywind]

Tracking Info For Invest 98L

http://www.wunderground.com/tropical/at ... track.html


Time Lat Lon Wind(mph) Pressure Storm type
-------------------------------------------------------------
12 GMT 07/22/13 12.7N 17.1W 20 1010 Invest
18 GMT 07/22/13 12.2N 18.9W 25 1009 Invest
18 GMT 07/22/13 12.2N 18.9W 25 1009 Invest
00 GMT 07/23/13 12.3N 21.3W 25 1010 Invest
06 GMT 07/23/13 12.3N 21.8W 25 1010 Invest
12 GMT 07/23/13 12.2N 22.7W 25 1009 Invest
18 GMT 07/23/13 12.3N 23.7W 25 1008 Invest
00 GMT 07/24/13 13.3N 25.6W 25 1008 Invest

[ozonepete]

Ah, ok, thanks guys. 13 knots (15 mph) seems very reasonable.

[Blown Away]

00z...TVCN pointing towards PR...Curious to see SHIP/DSHP predictions...

[cycloneye]

Latest ASCAT pass made at 7:24 PM EDT.

[Gustywind]

Levi Cowan's prediction...
http://www.tropicaltidbits.com

Given its prediction looks like all the islands between Martinica and PR seems on the path of 98L . Not good news if this verifies, but hopefully we're far far away from reality and we have time to watch 98L.

With my untrained eyes, the latest two positions try to show a more west direction or slight wnw when approaching the Leewards islands especially the Northern islands. Is the ridge is expected to be stronger near the 55W?

Let's wait and see what could happens with this feature.





The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of this poster. Please refer to the NHC and NWS products.

[ozonepete]

Clearly closed off. Since it's had a decent amount of convection near or over the center all day it probably qualifies as a TD right now - though it's hard to read the speed on the wind barbs - some are 30 knots?

[cycloneye]

SHIP Intensity.

Code: Select all

        *   ATLANTIC SHIPS INTENSITY FORECAST       *
                    * GOES AVAILABLE,       OHC AVAILABLE       *
                    *      INVEST  AL982013  07/24/13  00 UTC   *

TIME (HR)          0     6    12    18    24    36    48    60    72    84    96   108   120
V (KT) NO LAND    25    26    29    32    34    40    44    47    51    54    56    58    59
V (KT) LAND       25    26    29    32    34    40    44    47    51    54    56    58    59
V (KT) LGE mod    25    26    27    29    32    37    42    46    50    53    58    62    65
Storm Type      TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP

SHEAR (KT)        10     9     8     2     2     3    10     9    12    12    12    12    17
SHEAR ADJ (KT)    -5    -2    -1     1     0     0    -2     0    -4     1     1     0     0
SHEAR DIR         47    36    42   348   253   235   217   248   246   273   231   250   233
SST (C)         26.5  26.6  26.4  25.8  25.3  25.5  26.0  26.7  27.2  27.5  27.9  28.0  28.0
POT. INT. (KT)   121   123   120   115   110   113   117   123   129   133   138   138   138
ADJ. POT. INT.   121   124   121   114   109   113   116   121   127   133   137   133   130
200 MB T (C)   -53.6 -53.8 -53.9 -53.9 -54.1 -54.5 -54.1 -54.3 -54.3 -54.5 -54.1 -54.6 -54.2
TH_E DEV (C)       4     4     5     5     4     5     7     7     9     9    11    11    11
700-500 MB RH     75    75    72    72    73    70    59    54    52    48    47    49    49
GFS VTEX (KT)      8     8     8     9     9    10     9     8     8     8     8     8     8
850 MB ENV VOR    11     9    14    25    30    23    25     9     5    -7    -4   -14   -10
200 MB DIV        16     0    -3    15     7    20    19    13    -3     7    26    27    12
700-850 TADV      -2    -6    -4     0    -1     2     6    10     5     4    -2    -7    -6
LAND (KM)        888  1066  1248  1434  1621  2029  1840  1648  1514  1324  1046   696   434
LAT (DEG N)     13.3  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)     25.6 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)    16    18    18    18    18    20    19    17    17    19    18    14    12
HEAT CONTENT       1     1     0     0     0     0     0     3    11     4    22    16    30

  FORECAST TRACK FROM OFPI      INITIAL HEADING/SPEED (DEG/KT):285/ 13      CX,CY: -12/  3
  T-12 MAX WIND:  25            PRESSURE OF STEERING LEVEL (MB):  559  (MEAN=623)
  GOES IR BRIGHTNESS TEMP. STD DEV.  50-200 KM RAD:  23.4 (MEAN=14.5)
  % GOES IR PIXELS WITH T < -20 C    50-200 KM RAD:  44.0 (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.  20.  25.  27.  29.  31.
  VERTICAL SHEAR MAG     1.   2.   4.   5.   8.  10.  11.  11.  10.  10.   9.   8.
  VERTICAL SHEAR ADJ     0.   0.   0.   1.   1.   1.   1.   2.   2.   1.   1.   1.
  VERTICAL SHEAR DIR     1.   2.   2.   2.   1.   0.  -2.  -4.  -5.  -7.  -9. -10.
  PERSISTENCE            0.  -1.  -1.  -1.  -1.  -1.  -1.  -1.   0.   0.   0.   0.
  200/250 MB TEMP.       0.   0.   0.   0.   1.   2.   3.   3.   4.   5.   6.   7.
  THETA_E EXCESS         0.  -1.  -2.  -3.  -4.  -6.  -7.  -8.  -9. -10.  -9.  -9.
  700-500 MB RH          0.   0.   0.  -1.  -1.  -1.  -2.  -2.  -2.  -2.  -1.  -1.
  GFS VORTEX TENDENCY    0.   0.   0.   0.   1.  -1.  -2.  -2.  -2.  -3.  -3.  -3.
  850 MB ENV VORTICITY   0.   0.   0.   0.   0.   0.   0.  -1.  -1.  -1.  -2.  -2.
  200 MB DIVERGENCE      0.   0.   0.  -1.  -1.  -1.  -1.  -1.  -2.  -1.  -1.  -1.
  850-700 T ADVEC        0.   0.   0.   0.   0.   0.   0.   0.   0.   0.   0.   0.
  ZONAL STORM MOTION     0.   0.   1.   1.   1.   2.   2.   2.   3.   3.   3.   3.
  STEERING LEVEL PRES    0.   0.   0.   0.   1.   1.   1.   1.   1.   1.   1.   0.
  DAYS FROM CLIM. PEAK   0.   0.   0.   0.   0.  -1.  -1.  -1.  -1.  -1.  -1.  -1.
  GOES PREDICTORS        0.  -1.  -1.  -1.  -2.  -3.  -3.  -4.  -4.  -4.  -3.  -3.
  OCEAN HEAT CONTENT     0.   0.   0.   0.   0.  -1.  -1.  -1.  -1.  -1.  -1.  -1.
                        ----------------------------------------------------------
  TOTAL CHANGE           1.   4.   7.   9.  15.  19.  22.  26.  29.  31.  33.  34.

   ** 2011 ATLANTIC RI INDEX AL982013     INVEST 07/24/13  00 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) :   6.1 Range: 26.2 to   3.2 Scaled/Wgted Val:  0.9/  1.7
 STD DEV OF IR BR TEMP :  23.4 Range: 34.1 to   3.2 Scaled/Wgted Val:  0.3/  0.7
 D200 (10**7s-1)       :   7.0 Range:-21.0 to 165.0 Scaled/Wgted Val:  0.2/  0.3
 POT = MPI-VMAX (KT)   :  92.8 Range: 33.8 to 126.5 Scaled/Wgted Val:  0.6/  0.7
 850-700 MB REL HUM (%):  74.4 Range: 56.0 to  85.0 Scaled/Wgted Val:  0.6/  0.4
 Heat content (KJ/cm2) :   0.4 Range:  0.0 to 130.0 Scaled/Wgted Val:  0.0/  0.0
 % area w/pixels <-30 C:  38.0 Range: 17.0 to 100.0 Scaled/Wgted Val:  0.3/  0.1
 
 Prob of RI for 25 kt RI threshold=    20% is   1.6 times the sample mean(12.8%)
 Prob of RI for 30 kt RI threshold=    13% is   1.6 times the sample mean( 8.4%)
 Prob of RI for 35 kt RI threshold=     2% is   0.3 times the sample mean( 5.0%)
 Prob of RI for 40 kt RI threshold=     1% is   0.3 times the sample mean( 3.4%)

** PROBLTY OF AT LEAST 1 SCNDRY EYEWL FORMTN EVENT AL982013     INVEST 07/24/2013  00 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)     <-- FULL MODEL PROB (RAN NORMALLY)