Tropical Depression 17W

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                 
     20231112 152612       GMI    7.8  138.9   N/A   N/A     N/A     N/A      N/A   25.0   7.2  139.9 Analysis Plot     
     20231112 163109     AMSR2    7.3  140.7   N/A   N/A     N/A     N/A      N/A   25.0   7.2  139.8 Analysis Plot     
     20231112 184248  SSMISF18    6.8  140.4   N/A   N/A     N/A     N/A      N/A   25.0   7.2  139.7 Analysis Plot     
     20231112 203542  SSMISF16    5.8  139.2   N/A   N/A     N/A     N/A      N/A   25.0   7.3  138.9 Analysis Plot     
     20231113 030844       GMI    6.3  138.9   N/A   N/A     N/A     N/A      N/A   25.0   7.1  138.2 Analysis Plot     
     20231113 084812  SSMISF17    7.9  138.8   268    7%    0.79   -0.79      N/A   25.0   7.9  138.8 Analysis Plot     
     20231113 144559       GMI    7.9  138.9   N/A   N/A     N/A     N/A      N/A   25.0   7.8  138.7 Analysis Plot     
     20231113 183012  SSMISF18    4.5  140.5   301    4%    1.31   -1.31      N/A   20.0   4.5  140.5 Analysis Plot     
     20231113 202308  SSMISF16    4.1  139.6   N/A   N/A     N/A     N/A      N/A   20.0   4.5  140.5 Analysis Plot     
     20231113 212908  SSMISF17    4.3  139.6   N/A   N/A     N/A     N/A      N/A   20.0   4.4  140.5 Analysis Plot     
     20231114 040031     AMSR2    4.4  140.2   257    7%    2.98   -2.98      N/A   20.0   4.3  140.3 Analysis Plot     
     20231114 083359  SSMISF17    4.4  140.1   223   N/A    1.68   -1.68      N/A   20.0   4.3  140.1 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.