Tropical Depression 21W

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                 
     20241006 152339       GMI   18.7  145.0    12   N/A    0.87   -0.87      N/A   30.0  19.1  145.6 Analysis Plot     
     20241006 162040     AMSR2   18.5  146.2   N/A   N/A     N/A     N/A      N/A   30.0  19.5  145.7 Analysis Plot     
     20241007 062053  SSMISF18   22.8  146.0   N/A   N/A     N/A     N/A      N/A   40.0  22.0  146.2 Analysis Plot     
     20241007 084013  SSMISF16   22.8  147.3   N/A   N/A     N/A     N/A      N/A   40.0  22.4  146.8 Analysis Plot     
     20241007 144042       GMI   23.5  147.3   N/A   N/A     N/A     N/A      N/A   35.0  23.5  147.4 Analysis Plot     
     20241007 185214  SSMISF18   24.0  147.6   N/A   N/A     N/A     N/A      N/A   35.0  24.1  147.7 Analysis Plot     
     20241008 040657       GMI   24.1  147.0    68   N/A    0.07   -0.07      N/A   30.0  24.4  147.1 Analysis Plot     
     20241008 060738  SSMISF18   24.2  146.9    46   N/A    2.57   -2.57      N/A   30.0  24.7  147.2 Analysis Plot     
     20241008 082617  SSMISF16   24.0  147.0    46   N/A    2.20   -2.20      N/A   30.0  24.4  147.1 Analysis Plot     
     20241008 160636     AMSR2   24.6  148.0   N/A   N/A     N/A     N/A      N/A   30.0  25.0  147.6 Analysis Plot     
     20241008 183733  SSMISF18   24.5  148.4    34   N/A    1.46   -1.46      N/A   20.0  24.9  148.3 Analysis Plot     
     20241008 205607  SSMISF16   25.3  148.9   N/A   N/A     N/A     N/A      N/A   25.0  25.4  148.4 Analysis Plot     
     20241009 032615       GMI   25.8  149.8   N/A   N/A     N/A     N/A      N/A   25.0  26.3  148.6 Analysis Plot     
     20241009 055422  SSMISF18   26.1  149.4   N/A   N/A     N/A     N/A      N/A   25.0  26.8  148.7 Analysis Plot     
     20241009 081331  SSMISF16   26.8  148.9   N/A   N/A     N/A     N/A      N/A   30.0  27.6  149.0 Analysis Plot     
     20241009 182140  SSMISF18   31.4  149.8   157   31%    2.10   -2.10      N/A   30.0  31.7  149.7 Analysis Plot     
     20241009 205841  SSMISF17   31.5  150.2   N/A   N/A     N/A     N/A      N/A   30.0  32.4  149.7 Analysis Plot     
     20241010 054238  SSMISF18   34.3  151.1   312    4%    1.84   -1.84      N/A   35.0  34.2  151.2 Analysis Plot     
     20241010 080228  SSMISF16   35.5  152.0   N/A   N/A     N/A     N/A      N/A   35.0  36.1  151.6 Analysis Plot     
     20241010 123218       GMI   37.4  153.1   N/A   N/A     N/A     N/A      N/A   35.0  37.0  152.0 Analysis Plot     
     20241010 155025     AMSR2   38.9  153.2   N/A   N/A     N/A     N/A      N/A   40.0  38.7  152.9 Analysis Plot     
     20241010 180549  SSMISF18   39.5  153.5   N/A   N/A     N/A     N/A      N/A   40.0  39.2  153.1 Analysis Plot     
     20241010 204215  SSMISF17   40.8  153.8   N/A   N/A     N/A     N/A      N/A   40.0  40.0  153.5 Analysis Plot     
     20241011 034052       GMI   43.7  153.2   N/A   N/A     N/A     N/A      N/A   40.0  42.1  154.1 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.