Tropical Depression 31P

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                 
     20250418 090128  SSMISF17  -12.5  138.8   N/A   N/A     N/A     N/A      N/A   35.0 -11.4  139.9 Analysis Plot     
     20250418 090125  SSMISF17  -11.6  140.1   235   N/A    1.75   -1.75      N/A   35.0 -11.6  140.1 Analysis Plot     
     20250418 161728     AMSR2  -12.3  140.8   N/A   N/A     N/A     N/A      N/A   35.0 -12.0  140.7 Analysis Plot     
     20250418 182251  SSMISF18  -12.4  140.4   N/A   N/A     N/A     N/A      N/A   30.0 -12.1  140.8 Analysis Plot     
     20250418 201107  SSMISF17  -11.9  141.7   N/A   N/A     N/A     N/A      N/A   30.0 -12.0  141.1 Analysis Plot     
     20250418 212202  SSMISF16  -13.1  140.8   N/A   N/A     N/A     N/A      N/A   30.0 -12.1  141.1 Analysis Plot     
     20250419 070000  SSMISF18  -13.5  141.4   N/A   N/A     N/A     N/A      N/A   30.0 -12.6  141.6 Analysis Plot     
     20250419 084653  SSMISF17  -13.8  141.3   N/A   N/A     N/A     N/A      N/A   30.0 -12.8  141.0 Analysis Plot     
     20250419 193016       GMI  -12.9  140.9    90   12%    0.04   -0.04      N/A   30.0 -12.5  140.9 Analysis Plot     
     20250419 210746  SSMISF16  -13.1  140.9   N/A   N/A     N/A     N/A      N/A   30.0 -12.5  140.7 Analysis Plot     
     20250420 064541  SSMISF18  -13.4  140.9   N/A   N/A     N/A     N/A      N/A   30.0 -12.4  140.6 Analysis Plot     
     20250420 083313  SSMISF17  -13.0  140.8   190    7%    0.04   -0.04      N/A   30.0 -12.6  140.6 Analysis Plot     
     20250420 160513     AMSR2  -12.4  139.6   223    8%    0.13   -0.13      N/A   30.0 -12.4  139.3 Analysis Plot     
     20250420 205412  SSMISF16  -12.8  139.1   N/A   N/A     N/A     N/A      N/A   30.0 -12.5  139.0 Analysis Plot     
     20250421 042021     AMSR2  -12.6  137.7   179   32%    3.08   -3.08      N/A   30.0 -11.9  137.7 Analysis Plot     
     20250421 063245  SSMISF18  -12.3  138.1   N/A   N/A     N/A     N/A      N/A   30.0 -11.9  137.6 Analysis Plot     
     20250421 080745       GMI  -11.0  136.1   N/A   N/A     N/A     N/A      N/A   35.0 -12.0  137.3 Analysis Plot     
     20250421 093059  SSMISF16  -12.4  137.6   N/A   N/A     N/A     N/A      N/A   35.0 -11.9  137.1 Analysis Plot     
     20250421 164839     AMSR2  -10.6  135.9   N/A   N/A     N/A     N/A      N/A   30.0 -11.2  135.5 Analysis Plot     
     20250421 210840  SSMISF17   -9.6  133.8   N/A   N/A     N/A     N/A      N/A   30.0 -10.6  134.8 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.