Tropical Depression 17S

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                 
     20230328 231609  SSMISF17  -14.1  100.4   N/A   N/A     N/A     N/A      N/A   40.0 -13.9  101.6 Analysis Plot     
     20230329 104715  SSMISF16  -14.0  102.0    68   46%    3.68   -3.68      N/A   40.0 -14.1  101.9 Analysis Plot     
     20230329 115152  SSMISF17  -14.1  102.4    57   38%    6.18   -6.18      N/A   40.0 -14.1  102.1 Analysis Plot     
     20230329 233807       GMI  -14.7  104.0    34  100%   34.00  -49.00      N/A   50.0 -14.8  103.7 Analysis Plot     
     20230330 103329  SSMISF16  -15.6  105.3    12  100%   40.02   55.02  >65 kts   60.0 -15.6  105.3 Analysis Plot     
     20230330 113747  SSMISF17  -15.6  105.4    12  100%   35.69   50.69  >65 kts   60.0 -15.6  105.4 Analysis Plot     
     20230330 125339       GMI  -15.9  105.6   N/A   N/A     N/A     N/A      N/A   60.0 -15.6  105.5 Analysis Plot     
     20230330 214541  SSMISF16  -16.7  106.1    12  100%   58.80   73.80  >85 kts   95.0 -16.6  106.1 Analysis Plot     
     20230330 224953  SSMISF17  -16.9  106.1    12  100%   54.67   69.67  >85 kts   95.0 -16.7  106.2 Analysis Plot     
     20230331 101949  SSMISF16  -17.5  106.7    12  100%   29.27   44.27  >65 kts  110.0 -17.6  106.6 Analysis Plot     
     20230331 120109       GMI  -17.7  106.8    12  100%   60.29   75.29  >85 kts  110.0 -17.6  106.6 Analysis Plot     
     20230331 213325  SSMISF16  -18.5  107.0    12  100%   42.77   57.77  >65 kts  110.0 -18.5  107.1 Analysis Plot     
     20230331 223719  SSMISF17  -18.6  106.9    12  100%   59.80   74.80  >85 kts  110.0 -18.6  107.1 Analysis Plot     
     20230401 100630  SSMISF16  -19.4  107.1    12   75%    8.97    8.97      N/A   80.0 -19.3  106.8 Analysis Plot     
     20230401 111002  SSMISF17  -19.3  107.1    23   44%    8.61    8.61      N/A   80.0 -19.3  106.7 Analysis Plot     
     20230401 210219  SSMISF18  -19.9  106.6   146    1%    4.00    4.00      N/A   70.0 -19.9  106.7 Analysis Plot     
     20230401 223231       GMI  -19.4  106.4   N/A   N/A     N/A     N/A      N/A   70.0 -19.9  106.7 Analysis Plot     
     20230402 093532  SSMISF18  -19.8  105.5   201   N/A    3.45   -3.45      N/A   35.0 -19.8  105.5 Analysis Plot     
     20230402 115014       GMI  -19.8  105.4   N/A   N/A     N/A     N/A      N/A   35.0 -19.8  105.4 Analysis Plot     
     20230402 204845  SSMISF18  -19.7  104.5   N/A   N/A     N/A     N/A      N/A   25.0 -19.8  104.7 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.