Tropical Depression 20W

Passive Microwave (PMW) Intensity Information
Advanced Dvorak Technique
Version 9.1
 

       --Overpass--              --ARCHER--   Ring  Ring            Eye              BT   -Forecast-  
       Date    Time      Sat     Lat    Lon   Diam   Pct  TbDiff   Score  Meaning   Vmax  Lat    Lon                 
     20240927 091304  SSMISF16   19.4  127.7   N/A   N/A     N/A     N/A      N/A   25.0  19.8  125.9 Analysis Plot     
     20240927 093631  SSMISF17   19.9  127.6   N/A   N/A     N/A     N/A      N/A   25.0  19.7  125.9 Analysis Plot     
     20240927 192903  SSMISF18   19.6  125.8   N/A   N/A     N/A     N/A      N/A   35.0  19.0  125.6 Analysis Plot     
     20240927 214551  SSMISF16   18.9  125.5   279   15%    1.15   -1.15      N/A   35.0  18.9  125.5 Analysis Plot     
     20240927 220915  SSMISF17   19.2  125.8   N/A   N/A     N/A     N/A      N/A   35.0  18.9  125.5 Analysis Plot     
     20240928 045849     AMSR2   18.6  125.7    46    3%    5.03   -5.03      N/A   35.0  18.5  125.4 Analysis Plot     
     20240928 075405       GMI   19.3  125.9   N/A   N/A     N/A     N/A      N/A   35.0  18.5  125.3 Analysis Plot     
     20240928 092237  SSMISF17   19.5  124.9   N/A   N/A     N/A     N/A      N/A   35.0  18.5  125.2 Analysis Plot     
     20240928 171026     AMSR2   18.8  124.9    34   81%   16.76  -16.76      N/A   50.0  18.7  124.8 Analysis Plot     
     20240928 191635  SSMISF18   18.0  124.1   N/A   N/A     N/A     N/A      N/A   50.0  18.8  124.8 Analysis Plot     
     20240928 213321  SSMISF16   18.5  124.6    79  100%   30.03  -45.03      N/A   50.0  18.9  124.6 Analysis Plot     
     20240928 215527  SSMISF17   18.5  124.5    79  100%   28.63  -43.63      N/A   50.0  18.9  124.5 Analysis Plot     
     20240929 183959       GMI   19.9  122.4    79  100%   46.19   61.19  >85 kts   95.0  19.9  122.5 Analysis Plot     
     20240930 044804     AMSR2   20.5  121.5    57  100%   38.22   53.22  >65 kts  115.0  20.3  121.6 Analysis Plot     
     20240930 044805     AMSR2   20.4  121.5    57  100%   34.41   49.41  >65 kts  115.0  20.3  121.5 Analysis Plot     
     20240930 080402       GMI   20.5  121.0    46  100%   32.65   47.65  >65 kts  120.0  20.4  121.4 Analysis Plot     
     20240930 101410  SSMISF16   20.5  120.8    57  100%   44.96   59.96  >65 kts  120.0  20.7  120.9 Analysis Plot     
     20240930 202856  SSMISF18   20.4  119.9    34  100%   48.35   63.35  >85 kts  130.0  20.7  119.9 Analysis Plot     
     20240930 224620  SSMISF16   20.5  119.8    34  100%   62.63   77.63  >85 kts  130.0  20.8  119.8 Analysis Plot     
     20241001 074245  SSMISF18   21.1  119.3    23  100%   39.17   54.17  >65 kts  125.0  20.7  119.3 Analysis Plot     
     20241001 100020  SSMISF16   21.2  119.4    34   54%   23.50   23.50  >65 kts  125.0  21.0  119.4 Analysis Plot     
     20241001 102250  SSMISF17   21.3  119.6    34  100%   33.69   48.69  >65 kts  125.0  21.1  119.4 Analysis Plot     
     20241001 174013     AMSR2   21.5  119.3    23   47%   15.79   15.79      N/A  110.0  21.8  119.3 Analysis Plot     
     20241001 201442  SSMISF18   21.3  119.2    23  100%   35.74   50.74  >65 kts  105.0  21.7  119.3 Analysis Plot     
     20241001 225426  SSMISF17   21.3  119.4    23   26%   24.18   24.18  >65 kts  105.0  21.9  119.4 Analysis Plot     
     20241002 072941  SSMISF18   22.0  119.3    12  100%   21.68   36.68  >65 kts  100.0  22.0  119.5 Analysis Plot     
     20241002 100847  SSMISF17   22.1  119.6    12   25%   14.88   14.88      N/A  100.0  22.2  119.6 Analysis Plot     
     20241002 180720       GMI   22.2  119.6    46   36%   20.36   20.36  >65 kts  100.0  22.4  119.7 Analysis Plot     
     20241002 200059  SSMISF18   22.1  119.6    34   32%   11.00   11.00      N/A   90.0  22.3  119.9 Analysis Plot     
     20241002 221830  SSMISF16   22.2  119.9    34  100%   23.05   38.05  >65 kts   90.0  22.5  120.0 Analysis Plot     
     20241002 223950  SSMISF17   22.1  119.9    46   97%   19.77   34.77  >65 kts   90.0  22.5  120.0 Analysis Plot     
     20241003 073332       GMI   22.7  120.4    12   54%   13.97   13.97      N/A   65.0  22.9  120.3 Analysis Plot     
     20241003 095501  SSMISF17   23.0  121.3   N/A   N/A     N/A     N/A      N/A   65.0  23.0  120.4 Analysis Plot     
     20241003 172545       GMI   23.2  121.3    79    4%    0.95   -0.95      N/A   45.0  22.9  120.7 Analysis Plot     
     20241003 172746     AMSR2   23.3  121.3    79   N/A    2.76   -2.76      N/A   25.0  23.1  120.9 Analysis Plot     
     20241003 194721  SSMISF18   23.5  120.4   190   N/A    1.92   -1.92      N/A   25.0  23.2  120.9 Analysis Plot     
     20241003 220457  SSMISF16   23.6  120.4   N/A   N/A     N/A     N/A      N/A   25.0  23.4  120.9 Analysis Plot     
     20241003 222532  SSMISF17   23.4  120.8   N/A   N/A     N/A     N/A      N/A   25.0  23.4  120.9 Analysis Plot     
     20241004 065147       GMI   23.9  119.2   N/A   N/A     N/A     N/A      N/A   25.0  23.6  120.9 Analysis Plot     
     20241004 070355  SSMISF18   22.5  122.6   N/A   N/A     N/A     N/A      N/A   25.0  23.6  120.9 Analysis Plot     
     20241004 092128  SSMISF16   23.4  122.6   N/A   N/A     N/A     N/A      N/A   25.0  23.7  120.9 Analysis Plot
 
 
Legend

  - Overpass Date/Time are determined from satellite overpass of targeted TC (position determined from Best Track Lat/Lon position). Date is YYYYMMDD and time in HHMMSS (UTC).

  - Forecast (Best Track) and ARCHER positions (deg) of the TC center at overpass day/time. Positive/Negative: Latitude = North/South Hemisphere; Longitude = Eastern/Western Hemisphere.

  - BT Vmax is the concurrent ATCF Best Track (BT) wind speed intensity estimate (Vmax) value from either NOAA/National Hurricane Center (NHC) (North Atlantic and Northeast Pacific), NOAA/Central Pacific Hurricane Center (CPHC) (North-central Pacific) or Joint Typhoon Warning Center (JTWC) (Northwest Pacific, Indian Ocean, or Southwest Pacific).

  - Sat is the satellite descriptor providing the overpass. Currently the satellites used are the DMSP/SSMIS-16/17/18, GPM/GMI, and GCOM/AMSR2.

  - Ring Diam (km) indicates the estimated surface eyewall diameter if one is analyzed in the PMW imagery. The value listed is the average PMW-estimated inner eyewall edge diameter minus 10 km for eyewall slope. N/A indicates no appreciable eyewall is analyzed.

  - Ring Pct is the percentage of the analyzed "ring" (eyewall inner boundary) that is 1) colder than the eye Tb (the "hot spot" -- warmest eye pixel) by at least 20K, or 2) that is colder than 232K and colder than the eye Tb by 10K, whichever is greater. Values are red if Ring % ≤65,yellow/brown if Ring % ≤85 and green if Ring % >85. N/A indicates no appreciable eyewall is analyzed. A value over 85% is used in the intensity score by adding 15 points to it.

  - TbDiff is the difference between the warmest eye pixel and the warmest pixel on the eyewall. This value is used in the Intensity Score. N/A indicates no appreciable eyewall is analyzed.

  - Eye Score values are based on the strength and organization of the convective/eyewall signatures in the PMW imagery, and based on the ARCHER center location. They normally range from 0 to 100 with empirically-determined thresholds related to intensity (Vmax) in the "Meaning" column (≥20 suggests ≥65kts; ≥60 suggests ≥85kts). Scores are listed as negative, and not used by the ADT, when the NHC, CPHC, or JTWC Best Track Vmax is <55 kts in order to filter out occasional "false eye" cases. A value of -920 is used when the warmest eye pixel is <200K to prevent false positives; -930 means edge of overpass and <85% of eyewall is captured and therefore can't fully be analyzed.