Point Forecast Matrices
Issued by NWS Tiyan, Guam

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FOMY50 PGUM 180621
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Point Forecast Matrices
National Weather Service Tiyan GU
421 PM ChST Tue Aug 18 2026

GUZ001-181800-
Guam International Airport-Tiyan GU
13.48N 144.79E Elev. 248 ft
421 PM ChST Tue Aug 18 2026

Date          Tue 08/18/26      Wed 08/19/26            Thu 08/20/26         Fri
ChST3hrly     13 16 19 22 01 04 07 10 13 16 19 22 01 04 07 10 13 16 19 22 01 04
UTC 3hrly     03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18

Min/Max                      76          87          77          87          77
Temp                82 79 77 76 77 83 87 86 84 82 79 78 78 83 87 86 84 82 79 78
Dewpt               77 77 77 76 77 78 78 78 79 79 79 78 78 79 79 79 79 79 79 78
RH                  85 94100100100 85 75 77 85 91100100100 88 77 80 85 91100100
Wind dir             N  N  N  N  N  N  N  N  N NE NE NE NE NE NE NE NE NE NE NE
Wind spd             5  5  5  5  8 10 11 11  9  6  5  5  5  6  6  5  4  3  2  1
Clouds              B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1
PoP 12hr                     40          40          40          30          30
QPF 12hr                   0.18        0.19        0.13        0.12        0.07
Rain shwrs           C  C  C  C  C  C  C  C  C  C  C  C  C  C  C  C  S  S  S  S
Tstms                S  S  S  S  S  S  S  S  S  S  S  S  S  S  S  S
Heat index          90 84          92100 99 96 91          94101100 96 92
Max heat         98    97          92   100    98    90    94   101    99    90


Date           08/21/26  Sat 08/22/26  Sun 08/23/26  Mon 08/24/26  Tue 08/25/26
ChST6hrly     10 16 22   04 10 16 22   04 10 16 22   04 10 16 22   04 10 16
UTC 6hrly     00 06 12   18 00 06 12   18 00 06 12   18 00 06 12   18 00 06

Max/Min          88      78    87      77    87      77    86      79    85
Temp          84 87 83   79 83 86 82   78 83 86 82   78 82 86 84   83 84 85
Dewpt         79 78 79   79 79 78 79   78 79 79 79   78 79 79 79   79 79 79
PWind dir         N       W    SW      SW    SW      SW    SW      SW    SW
Wind char        LT      LT    GN      GN    GN      GN    GN      GN    GN
Avg clouds    B1 B1 B1   B1 B1 B1 B2   B2 B1 B1 B1   B1 B1 B1 B1   B1 B1 B1
PoP 12hr         20      30    40      40    40      40    40      40    40
Rain shwrs     S  S  C    C  C  C  C    C  C  C  C    C  C  C  C    C  C  C
Tstms                S    S  S  S  S    S  S  S  S    S  S  S  S    S  S  S

$$
MPZ001-181800-
Rota International Airport-Sinapalu MP
14.17N 145.23E Elev. 592 ft
421 PM ChST Tue Aug 18 2026

Date          Tue 08/18/26      Wed 08/19/26            Thu 08/20/26         Fri
ChST3hrly     13 16 19 22 01 04 07 10 13 16 19 22 01 04 07 10 13 16 19 22 01 04
UTC 3hrly     03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18

Min/Max                      75          86          76          86          76
Temp                81 78 76 75 76 81 86 85 83 80 78 76 77 82 86 85 83 80 78 76
Dewpt               77 78 76 75 76 78 78 79 79 79 78 76 77 79 79 79 79 79 78 76
RH                  88100100100100 91 77 82 88 97100100100 91 80 82 88 97100100
Wind dir             N  N  N  N  N  N  N  N NE NE NE NE NE NE NE NE NE NE NE NE
Wind spd             6  5  5  6  9 11 12 12 11  9  8  6  6  8  8  6  6  5  4  3
Clouds              B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1
PoP 12hr                     30          40          40          30          30
QPF 12hr                   0.11        0.16        0.14        0.15        0.10
Rain shwrs           C  C  C  C  C  C  C  C  C  C  C  C  C  C  C  C  S  S  S  S
Tstms                S  S  S  S  S  S  S  S  S  S  S  S  S  S  S  S
Heat index          88             90 98 97 94 89          92 99 98 94 89
Max heat         97    96          90    98    97    85    92    99    97    85


Date           08/21/26  Sat 08/22/26  Sun 08/23/26  Mon 08/24/26  Tue 08/25/26
ChST6hrly     10 16 22   04 10 16 22   04 10 16 22   04 10 16 22   04 10 16
UTC 6hrly     00 06 12   18 00 06 12   18 00 06 12   18 00 06 12   18 00 06

Max/Min          86      76    86      76    86      77    84      79    83
Temp          82 85 80   76 82 85 80   76 82 85 81   78 81 84 84   83 83 83
Dewpt         79 79 79   76 79 79 79   76 79 79 79   78 79 79 79   79 79 79
PWind dir         N       W    SW      SW    SW      SW    SW      SW    SW
Wind char        LT      LT    GN      GN    GN      GN    GN      GN    GN
Avg clouds    B1 B1 B1   B1 B1 B1 B2   B2 B1 B1 B1   B1 B1 B1 B1   B1 B1 B1
PoP 12hr         20      30    40      40    40      40    40      40    40
Rain shwrs     S  S  C    C  C  C  C    C  C  C  C    C  C  C  C    C  C  C
Tstms                S    S  S  S  S    S  S  S  S    S  S  S  S    S  S  S

$$
MPZ002-181800-
Tinian-San Jose MP
14.97N 145.63E Elev. 74 ft
421 PM ChST Tue Aug 18 2026

Date          Tue 08/18/26      Wed 08/19/26            Thu 08/20/26         Fri
ChST3hrly     13 16 19 22 01 04 07 10 13 16 19 22 01 04 07 10 13 16 19 22 01 04
UTC 3hrly     03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18

Min/Max                      75          87          77          87          77
Temp                81 79 77 75 76 82 87 86 84 82 79 78 78 83 87 86 84 82 79 78
Dewpt               78 78 77 75 76 78 78 79 79 79 79 78 78 79 79 79 79 80 79 78
RH                  91 97100100100 88 75 80 85 91100100100 88 77 80 85 94100100
Wind dir             N  N  N  N  N  N NE NE NE NE NE NE NE NE NE NE NE NE NE NE
Wind spd             6  5  5  6  8 10 11 11 11 10  9  8  9  9  9  9  8  6  5  4
Clouds              B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1
PoP 12hr                     30          40          40          30          30
QPF 12hr                   0.23        0.23        0.17        0.20        0.17
Rain shwrs           C  C  C  C  C  C  C  C  C  C  C  C  C  C  C  C  S  S  S  S
Tstms                S  S  S  S  S  S  S  S  S  S  S  S  S  S  S  S
Heat index          90             92100 99 96 92          94101100 97 92
Max heat         98    97          92   100    99    90    94   101    99    91


Date           08/21/26  Sat 08/22/26  Sun 08/23/26  Mon 08/24/26  Tue 08/25/26
ChST6hrly     10 16 22   04 10 16 22   04 10 16 22   04 10 16 22   04 10 16
UTC 6hrly     00 06 12   18 00 06 12   18 00 06 12   18 00 06 12   18 00 06

Max/Min          87      77    87      77    87      77    86      79    85
Temp          83 86 82   78 83 86 82   78 83 86 82   78 82 85 84   83 84 85
Dewpt         79 79 79   78 79 79 79   78 79 79 79   78 79 79 79   79 79 79
PWind dir        NE      NW     W      SW    SW      SW    SW      SW    SW
Wind char        LT      LT    GN      GN    GN      GN    GN      GN    GN
Avg clouds    B1 B1 B1   B1 B2 B2 B2   B2 B1 B1 B1   B1 B1 B1 B1   B1 B1 B1
PoP 12hr         20      30    50      50    40      40    40      40    40
Rain shwrs     S  S  C    C  C  C  C    C  C  C  C    C  C  C  C    C  C  C
Tstms                S    S  S  S  S    S  S  S  S    S  S  S  S    S  S  S

$$
MPZ003-181800-
Saipan International Airport-Obyan MP
15.11N 145.72E Elev. 215 ft
421 PM ChST Tue Aug 18 2026

Date          Tue 08/18/26      Wed 08/19/26            Thu 08/20/26         Fri
ChST3hrly     13 16 19 22 01 04 07 10 13 16 19 22 01 04 07 10 13 16 19 22 01 04
UTC 3hrly     03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18

Min/Max                      75          87          77          87          77
Temp                81 79 77 75 76 82 87 86 84 82 79 78 78 83 87 86 84 82 79 78
Dewpt               78 78 77 75 76 78 79 79 79 79 79 78 78 79 79 79 79 80 79 78
RH                  91 97100100100 88 77 80 85 91100100100 88 77 80 85 94100100
Wind dir            NE  N  N  N  N NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE
Wind spd             6  5  5  6  9 10 11 11 11 10  9  8  9 10 10  9  8  6  5  4
Clouds              B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1 B1
PoP 12hr                     30          40          40          30          30
QPF 12hr                   0.23        0.22        0.16        0.20        0.16
Rain shwrs           C  C  C  C  C  C  C  C  C  C  C  C  C  C  C  C  S  S  S  S
Tstms                S  S  S  S  S  S  S  S  S  S  S  S  S  S  S  S
Heat index          90             92100 99 96 92          94101100 97 92
Max heat         98    97          92   100    99    90    94   101    99    90


Date           08/21/26  Sat 08/22/26  Sun 08/23/26  Mon 08/24/26  Tue 08/25/26
ChST6hrly     10 16 22   04 10 16 22   04 10 16 22   04 10 16 22   04 10 16
UTC 6hrly     00 06 12   18 00 06 12   18 00 06 12   18 00 06 12   18 00 06

Max/Min          87      77    87      77    87      77    86      79    85
Temp          83 86 82   78 83 86 82   78 83 86 82   78 82 85 84   83 84 85
Dewpt         79 79 79   78 79 79 79   78 79 79 79   78 79 79 79   79 79 79
PWind dir        NE      NW     W      SW    SW      SW    SW      SW    SW
Wind char        LT      LT    GN      GN    GN      GN    GN      GN    GN
Avg clouds    B1 B1 B1   B1 B2 B2 B2   B2 B1 B1 B1   B1 B1 B1 B1   B1 B1 B1
PoP 12hr         20      30    50      50    40      40    40      40    40
Rain shwrs     S  S  C    C  C  C  C    C  C  C  C    C  C  C  C    C  C  C
Tstms                S    S  S  S  S    S  S  S  S    S  S  S  S    S  S  S

$$