Routine Fire Wx Fcst (With/Without 6-10 Day Outlook)
Issued by NWS San Juan, PR

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FNCA52 TJSJ 210911
FWFSJU

Fire Weather Planning Forecast for Puerto Rico
National Weather Service San Juan PR
511 AM AST Mon Jul 21 2025

.DISCUSSION...

Relative humidity values are forecast to drop to around critical
thresholds for the southern portions of Puerto Rico. Accompanied
with east to east-northeast winds between 15 and 18 mph with
higher gusts, with variations due to sea breeze. KBDI values are
between 613 and 661 in Cabo Rojo and Guanica, respectively. All
these factors will elevate the fire danger risk today across
southern portions of Puerto Rico.

Fire and emergency officials should be aware that weather
conditions are becoming more conducive for the ignition and
spread of wildfires.

PRZ014-220915-
Southeast Coastal Plains-
511 AM AST Mon Jul 21 2025

                      Today        Tonight      Tue

Cloud Cover           Mclear       Pcldy        Mclear
Precip Type           Showers      Showers      Showers
Chance Precip (%)     20           30           10
Temp (24h trend)      91 (+1)      75 (-1)      92
RH % (24h trend)      50 (-5)      95 (+8)      56
Wind 20ft/early(mph)  E 18 G22     E 12         E 17 G23
Wind 20ft/late(mph)   E 16 G22     E 12         E 17 G23
Mixing Hgt(ft-agl/msl)5510                      5070
Transport Wnd (mph)   E 16                      E 21
Vent Rate (kt-ft)     77140                     91260
Dispersion            5                         5
DSI                   6            5            6
RH Recovery                        Excellent

Remarks...None.

$$

PRZ015-220915-
Southern Hills-
511 AM AST Mon Jul 21 2025

                      Today        Tonight      Tue

Cloud Cover           Mclear       Pcldy        Mclear
Precip Type           Showers      Showers      Showers
Chance Precip (%)     30           20           20
Temp (24h trend)      88 (+4)      71 (-2)      87
RH % (24h trend)      55 (-14)     99 (+7)      62
Wind 20ft/early(mph)  E 13         NE 11        E 14
Wind 20ft/late(mph)   E 13         NE 11        E 14
Mixing Hgt(ft-agl/msl)6180                      5770
Transport Wnd (mph)   E 14                      E 21
Vent Rate (kt-ft)     74160                     103860
Dispersion            5                         5
DSI                   6            3            6
RH Recovery                        Excellent

Remarks...None.

$$

PRZ016-220915-
North Coastal Plains-
511 AM AST Mon Jul 21 2025

                      Today        Tonight      Tue

Cloud Cover           Pcldy        Pcldy        Pcldy
Precip Type           Showers      Showers      Showers
Chance Precip (%)     20           40           50
Temp (24h trend)      89 (-1)      74 (-1)      90
RH % (24h trend)      59 (-7)      99 (+6)      64
Wind 20ft/early(mph)  E 19         E 18         E 20 G23
Wind 20ft/late(mph)   E 19         E 18         E 20 G23
Mixing Hgt(ft-agl/msl)5310                      5580
Transport Wnd (mph)   E 16                      E 21
Vent Rate (kt-ft)     74340                     100440
Dispersion            5                         5
DSI                   6            6            6
RH Recovery                        Excellent

Remarks...None.

$$

PRZ017-220915-
Northern Hills-
511 AM AST Mon Jul 21 2025

                      Today        Tonight      Tue

Cloud Cover           Mclear       Mclear       Pcldy
Precip Type           Showers      Showers      Tstms
Chance Precip (%)     40           20           50
Temp (24h trend)      88 (+1)      72 (0)       88
RH % (24h trend)      62 (-6)      100 (+3)     65
Wind 20ft/early(mph)  E 16         E 16         E 18
Wind 20ft/late(mph)   E 16         E 16         E 18
Mixing Hgt(ft-agl/msl)6470                      6980
Transport Wnd (mph)   E 13                      E 17
Vent Rate (kt-ft)     71170                     104700
Dispersion            5                         5
DSI                   6            5            6
RH Recovery                        Excellent

Remarks...None.

$$

PRZ018-220915-
West Coast-
511 AM AST Mon Jul 21 2025

                      Today        Tonight      Tue

Cloud Cover           Pcldy        Mclear       Pcldy
Precip Type           Tstms        None         Showers
Chance Precip (%)     50           0            40
Temp (24h trend)      92 (+3)      72 (-1)      91
RH % (24h trend)      54 (-12)     99 (+4)      61
Wind 20ft/early(mph)  E 13         E 13         E 16 G18
Wind 20ft/late(mph)   E 13         E 13         E 16 G18
Mixing Hgt(ft-agl/msl)5280                      4880
Transport Wnd (mph)   E 10                      E 15
Vent Rate (kt-ft)     47520                     63440
Dispersion            5                         5
DSI                   6            4            6
RH Recovery                        Excellent

Remarks...None.

$$

PRZ019-220915-
Eastern Interior-
511 AM AST Mon Jul 21 2025

                      Today        Tonight      Tue

Cloud Cover           Pcldy        Pcldy        Pcldy
Precip Type           Showers      Showers      Showers
Chance Precip (%)     20           50           40
Temp (24h trend)      88 (+1)      73 (-1)      88
RH % (24h trend)      58 (-8)      100 (+7)     65
Wind 20ft/early(mph)  E 12         E 12         E 14
Wind 20ft/late(mph)   E 12         E 12         E 14
Mixing Hgt(ft-agl/msl)6240                      5910
Transport Wnd (mph)   E 15                      E 20
Vent Rate (kt-ft)     81120                     100470
Dispersion            5                         5
DSI                   6            4            6
RH Recovery                        Excellent

Remarks...None.

$$

PRZ022-220915-
Luquillo Mountain Range-
511 AM AST Mon Jul 21 2025

                      Today        Tonight      Tue

Cloud Cover           Pcldy        Mcldy        Pcldy
Precip Type           Showers      Showers      Showers
Chance Precip (%)     40           70           50
Temp (24h trend)      84 (+4)      70 (-2)      84
RH % (24h trend)      68 (-9)      100 (+2)     76
Wind 20ft/early(mph)  E 10         E  9         E 13
Wind 20ft/late(mph)   E 10         E  9         E 13
Mixing Hgt(ft-agl/msl)4690                      4190
Transport Wnd (mph)   E 15                      E 21
Vent Rate (kt-ft)     60970                     75420
Dispersion            5                         5
DSI                   6            5            6
RH Recovery                        Excellent

Remarks...None.

$$

PRZ023-220915-
Central Mountain Range-
511 AM AST Mon Jul 21 2025

                      Today        Tonight      Tue

Cloud Cover           Pcldy        Mclear       Pcldy
Precip Type           Tstms        Showers      Showers
Chance Precip (%)     50           10           50
Temp (24h trend)      87 (+5)      68 (-2)      86
RH % (24h trend)      61 (-13)     100 (+3)     67
Wind 20ft/early(mph)  E 10         E 11         E 11
Wind 20ft/late(mph)   E 10         E 11         E 11
Mixing Hgt(ft-agl/msl)7520                      7540
Transport Wnd (mph)   E 10                      E 14
Vent Rate (kt-ft)     67680                     90480
Dispersion            5                         5
DSI                   5            2            6
RH Recovery                        Excellent

Remarks...None.

$$

PRZ024-220915-
Cayey Mountain Range-
511 AM AST Mon Jul 21 2025

                      Today        Tonight      Tue

Cloud Cover           Pcldy        Pcldy        Pcldy
Precip Type           Showers      Showers      Showers
Chance Precip (%)     20           50           20
Temp (24h trend)      84 (+2)      71 (-1)      83
RH % (24h trend)      63 (-9)      100 (+2)     71
Wind 20ft/early(mph)  E 10         NE  9        E 12
Wind 20ft/late(mph)   E 10         NE  9        E 12
Mixing Hgt(ft-agl/msl)5320                      4970
Transport Wnd (mph)   E 15                      E 21
Vent Rate (kt-ft)     69160                     89460
Dispersion            5                         5
DSI                   6            4            6
RH Recovery                        Excellent

Remarks...None.

$$

PRZ025-220915-
Vieques-
511 AM AST Mon Jul 21 2025

                      Today        Tonight      Tue

Cloud Cover           Pcldy        Mcldy        Pcldy
Precip Type           Showers      Showers      Showers
Chance Precip (%)     20           70           40
Temp (24h trend)      89 (+1)      77 (-1)      89
RH % (24h trend)      55 (-8)      94 (+7)      62
Wind 20ft/early(mph)  E 14 G17     E 18 G21     E 17 G21
Wind 20ft/late(mph)   E 14 G17     E 18 G21     E 17 G21
Mixing Hgt(ft-agl/msl)3980                      3630
Transport Wnd (mph)   E 17                      E 22
Vent Rate (kt-ft)     59700                     68970
Dispersion            5                         5
DSI                   6            6            6
RH Recovery                        Excellent

Remarks...None.

$$

PRZ026-220915-
Culebra-
511 AM AST Mon Jul 21 2025

                      Today        Tonight      Tue

Cloud Cover           Pcldy        Mcldy        Pcldy
Precip Type           Showers      Showers      Showers
Chance Precip (%)     30           70           40
Temp (24h trend)      91 (+2)      77 (-2)      90
RH % (24h trend)      57 (-9)      93 (+7)      62
Wind 20ft/early(mph)  E 13 G17     E 18 G22     E 17 G21
Wind 20ft/late(mph)   E 13 G17     E 18 G22     E 17 G21
Mixing Hgt(ft-agl/msl)3960                      3680
Transport Wnd (mph)   E 20                      E 22
Vent Rate (kt-ft)     67320                     69920
Dispersion            5                         5
DSI                   6            6            6
RH Recovery                        Excellent

Remarks...None.

$$

PRZ027-220915-
Southwest Coastal Plains and Mona Island-
511 AM AST Mon Jul 21 2025

                      Today        Tonight      Tue

Cloud Cover           Mclear       Mclear       Mclear
Precip Type           Showers      Showers      Showers
Chance Precip (%)     20           10           10
Temp (24h trend)      93 (+3)      75 (-1)      92
RH % (24h trend)      49 (-7)      88 (+3)      57
Wind 20ft/early(mph)  SE 19 G25    E 11         SE 21 G28
Wind 20ft/late(mph)   SE 19 G25    E 11         SE 21 G28
Mixing Hgt(ft-agl/msl)5570                      5250
Transport Wnd (mph)   E 17                      E 24
Vent Rate (kt-ft)     83550                     110250
Dispersion            5                         5
DSI                   6            4            6
RH Recovery                        Excellent

Remarks...None.

$$

VIZ001-220915-
Saint Thomas and Saint John-
511 AM AST Mon Jul 21 2025

                      Today        Tonight      Tue

Cloud Cover           Mclear       Pcldy        Pcldy
Precip Type           Showers      Showers      Showers
Chance Precip (%)     30           60           20
Temp (24h trend)      86 (0)       76 (-3)      87
RH % (24h trend)      64 (-6)      96 (+10)     67
Wind 20ft/early(mph)  E 14 G19     E 18 G22     E 17 G22
Wind 20ft/late(mph)   E 14 G19     E 18 G22     E 17 G22
Mixing Hgt(ft-agl/msl)3680                      3630
Transport Wnd (mph)   E 20                      E 24
Vent Rate (kt-ft)     62560                     76230
Dispersion            5                         5
DSI                   6            6            6
RH Recovery                        Excellent

Remarks...None.

$$

VIZ002-220915-
St Croix-
511 AM AST Mon Jul 21 2025

                      Today        Tonight      Tue

Cloud Cover           Pcldy        Pcldy        Pcldy
Precip Type           Showers      Showers      Showers
Chance Precip (%)     40           60           20
Temp (24h trend)      89 (+2)      77 (-2)      88
RH % (24h trend)      61 (-5)      95 (+9)      66
Wind 20ft/early(mph)  E 13 G17     E 17 G21     E 17 G21
Wind 20ft/late(mph)   E 13 G17     E 17 G21     E 17 G21
Mixing Hgt(ft-agl/msl)4460                      4800
Transport Wnd (mph)   E 17                      E 25
Vent Rate (kt-ft)     66900                     105600
Dispersion            5                         5
DSI                   6            6            6
RH Recovery                        Excellent

Remarks...None.

$$


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