850
FNCA52 TJSJ 190909
FWFSJU
FIRE WEATHER PLANNING FORECAST FOR PUERTO RICO
NATIONAL WEATHER SERVICE SAN JUAN PR
509 AM AST FRI DEC 19 2025
DISCUSSION
CALM WEATHER CONDITIONS WILL PREVAIL TODAY AS A DRIER AIR MASS
MOVES ACROSS THE ISLANDS. DURING THIS TIME, RH AND THE KBDI ARE
NOT EXPECTED TO MEET FIRE WEATHER CRITERIA. HOWEVER, WE EXPECT
EASTERLY WINDS AT 10 TO 18 MPH WITH HIGHER GUSTS ARE ACROSS THE
COASTAL SECTIONS TODAY. THE FIRE DANGER WILL REMAIN LOW TODAY.
PRZ014-200915-
SOUTHEAST COASTAL PLAINS-
509 AM AST FRI DEC 19 2025
TODAY TONIGHT SAT
CLOUD COVER MCLEAR MCLEAR PCLDY
PRECIP TYPE SHOWERS NONE SHOWERS
CHANCE PRECIP (%) 0 0 40
TEMP (24H TREND) 88 (+1) 68 (-4) 88
RH % (24H TREND) 56 (-3) 93 (+1) 56
WIND 20FT/EARLY(MPH) E 17 G22 NE 12 E 14 G20
WIND 20FT/LATE(MPH) E 17 G22 NE 12 E 14 G20
MIXING HGT(FT-AGL/MSL)5200 4950
TRANSPORT WND (MPH) E 14 E 14
VENT RATE (KT-FT) 62400 59400
DISPERSION 5 5
DSI 5 3 5
RH RECOVERY EXCELLENT
REMARKS...NONE.
PRZ015-200915-
SOUTHERN HILLS-
509 AM AST FRI DEC 19 2025
TODAY TONIGHT SAT
CLOUD COVER MCLEAR MCLEAR PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 10 10 50
TEMP (24H TREND) 83 (+1) 65 (-5) 84
RH % (24H TREND) 61 (-3) 97 (+4) 60
WIND 20FT/EARLY(MPH) E 12 NE 10 E 11
WIND 20FT/LATE(MPH) E 12 NE 10 E 11
MIXING HGT(FT-AGL/MSL)5650 4990
TRANSPORT WND (MPH) E 13 E 14
VENT RATE (KT-FT) 62150 59880
DISPERSION 5 5
DSI 5 2 5
RH RECOVERY EXCELLENT
REMARKS...NONE.
PRZ016-200915-
NORTH COASTAL PLAINS-
509 AM AST FRI DEC 19 2025
TODAY TONIGHT SAT
CLOUD COVER MCLEAR MCLEAR PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 10 10 30
TEMP (24H TREND) 86 (0) 69 (-3) 86
RH % (24H TREND) 62 (-2) 98 (+1) 64
WIND 20FT/EARLY(MPH) E 16 G18 E 13 NE 16
WIND 20FT/LATE(MPH) E 16 G18 E 13 NE 16
MIXING HGT(FT-AGL/MSL)4850 4330
TRANSPORT WND (MPH) E 16 E 17
VENT RATE (KT-FT) 67900 64950
DISPERSION 5 5
DSI 6 4 6
RH RECOVERY EXCELLENT
REMARKS...NONE.
PRZ017-200915-
NORTHERN HILLS-
509 AM AST FRI DEC 19 2025
TODAY TONIGHT SAT
CLOUD COVER MCLEAR MCLEAR PCLDY
PRECIP TYPE SHOWERS NONE SHOWERS
CHANCE PRECIP (%) 10 0 30
TEMP (24H TREND) 85 (0) 66 (-4) 84
RH % (24H TREND) 60 (-1) 98 (-1) 62
WIND 20FT/EARLY(MPH) E 14 E 12 NE 13
WIND 20FT/LATE(MPH) E 14 E 12 NE 13
MIXING HGT(FT-AGL/MSL)5290 4680
TRANSPORT WND (MPH) E 13 E 16
VENT RATE (KT-FT) 58190 65520
DISPERSION 5 5
DSI 5 4 6
RH RECOVERY EXCELLENT
REMARKS...NONE.
PRZ018-200915-
WEST COAST-
509 AM AST FRI DEC 19 2025
TODAY TONIGHT SAT
CLOUD COVER MCLEAR MCLEAR PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 40 20 50
TEMP (24H TREND) 87 (0) 67 (-3) 88
RH % (24H TREND) 60 (+1) 98 (+3) 58
WIND 20FT/EARLY(MPH) SE 12 E 14 E 16
WIND 20FT/LATE(MPH) SE 12 E 14 E 16
MIXING HGT(FT-AGL/MSL)4540 4400
TRANSPORT WND (MPH) E 9 E 12
VENT RATE (KT-FT) 36320 44000
DISPERSION 5 5
DSI 5 3 5
RH RECOVERY EXCELLENT
REMARKS...NONE.
PRZ019-200915-
EASTERN INTERIOR-
509 AM AST FRI DEC 19 2025
TODAY TONIGHT SAT
CLOUD COVER MCLEAR MCLEAR PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 10 10 50
TEMP (24H TREND) 84 (+1) 66 (-5) 84
RH % (24H TREND) 63 (-4) 99 (+1) 65
WIND 20FT/EARLY(MPH) E 12 E 10 NE 12
WIND 20FT/LATE(MPH) E 12 E 10 NE 12
MIXING HGT(FT-AGL/MSL)5320 4290
TRANSPORT WND (MPH) E 14 E 15
VENT RATE (KT-FT) 63840 55770
DISPERSION 5 5
DSI 5 2 5
RH RECOVERY EXCELLENT
REMARKS...NONE.
PRZ022-200915-
LUQUILLO MOUNTAIN RANGE-
509 AM AST FRI DEC 19 2025
TODAY TONIGHT SAT
CLOUD COVER MCLEAR PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 10 30 40
TEMP (24H TREND) 79 (+1) 65 (-4) 79
RH % (24H TREND) 70 (-5) 100 (0) 71
WIND 20FT/EARLY(MPH) E 11 E 8 E 10
WIND 20FT/LATE(MPH) E 11 E 8 E 10
MIXING HGT(FT-AGL/MSL)4760 3560
TRANSPORT WND (MPH) E 16 E 16
VENT RATE (KT-FT) 66640 49840
DISPERSION 5 5
DSI 5 3 5
RH RECOVERY EXCELLENT
REMARKS...NONE.
PRZ023-200915-
CENTRAL MOUNTAIN RANGE-
509 AM AST FRI DEC 19 2025
TODAY TONIGHT SAT
CLOUD COVER MCLEAR MCLEAR PCLDY
PRECIP TYPE SHOWERS NONE SHOWERS
CHANCE PRECIP (%) 30 0 50
TEMP (24H TREND) 83 (+3) 63 (-5) 82
RH % (24H TREND) 60 (-2) 98 (+2) 61
WIND 20FT/EARLY(MPH) E 10 E 11 NE 12
WIND 20FT/LATE(MPH) E 10 E 11 NE 12
MIXING HGT(FT-AGL/MSL)6370 5050
TRANSPORT WND (MPH) E 10 E 15
VENT RATE (KT-FT) 57330 65650
DISPERSION 5 5
DSI 5 2 5
RH RECOVERY EXCELLENT
REMARKS...NONE.
PRZ024-200915-
CAYEY MOUNTAIN RANGE-
509 AM AST FRI DEC 19 2025
TODAY TONIGHT SAT
CLOUD COVER MCLEAR MCLEAR PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 10 20 50
TEMP (24H TREND) 79 (0) 65 (-4) 80
RH % (24H TREND) 69 (-3) 100 (0) 70
WIND 20FT/EARLY(MPH) E 11 NE 8 E 10
WIND 20FT/LATE(MPH) E 11 NE 8 E 10
MIXING HGT(FT-AGL/MSL)4980 4000
TRANSPORT WND (MPH) E 16 E 15
VENT RATE (KT-FT) 69720 52000
DISPERSION 5 5
DSI 5 2 5
RH RECOVERY EXCELLENT
REMARKS...NONE.
PRZ025-200915-
VIEQUES-
509 AM AST FRI DEC 19 2025
TODAY TONIGHT SAT
CLOUD COVER CLEAR MCLEAR PCLDY
PRECIP TYPE NONE SHOWERS SHOWERS
CHANCE PRECIP (%) 0 20 20
TEMP (24H TREND) 84 (-1) 73 (-1) 85
RH % (24H TREND) 61 (-4) 92 (0) 61
WIND 20FT/EARLY(MPH) E 13 G17 NE 13 E 13 G17
WIND 20FT/LATE(MPH) E 13 G17 NE 13 E 13 G17
MIXING HGT(FT-AGL/MSL)3590 3420
TRANSPORT WND (MPH) E 20 E 18
VENT RATE (KT-FT) 61030 54720
DISPERSION 5 5
DSI 6 6 6
RH RECOVERY EXCELLENT
REMARKS...NONE.
PRZ026-200915-
CULEBRA-
509 AM AST FRI DEC 19 2025
TODAY TONIGHT SAT
CLOUD COVER CLEAR MCLEAR MCLEAR
PRECIP TYPE NONE SHOWERS SHOWERS
CHANCE PRECIP (%) 0 10 20
TEMP (24H TREND) 86 (0) 73 (-2) 87
RH % (24H TREND) 60 (-6) 91 (+1) 59
WIND 20FT/EARLY(MPH) E 13 G17 E 13 G17 E 13 G17
WIND 20FT/LATE(MPH) E 13 G17 E 13 G17 E 13 G17
MIXING HGT(FT-AGL/MSL)3480 3470
TRANSPORT WND (MPH) E 16 E 17
VENT RATE (KT-FT) 48720 52050
DISPERSION 5 5
DSI 6 6 6
RH RECOVERY EXCELLENT
REMARKS...NONE.
PRZ027-200915-
SOUTHWEST COASTAL PLAINS AND MONA ISLAND-
509 AM AST FRI DEC 19 2025
TODAY TONIGHT SAT
CLOUD COVER MCLEAR MCLEAR MCLEAR
PRECIP TYPE SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 20 10 40
TEMP (24H TREND) 88 (+1) 67 (-5) 89
RH % (24H TREND) 57 (0) 93 (+4) 55
WIND 20FT/EARLY(MPH) E 18 G23 E 12 E 13 G18
WIND 20FT/LATE(MPH) E 18 G23 E 12 E 13 G18
MIXING HGT(FT-AGL/MSL)5270 5080
TRANSPORT WND (MPH) E 12 E 10
VENT RATE (KT-FT) 52700 45720
DISPERSION 5 5
DSI 5 3 5
RH RECOVERY EXCELLENT
REMARKS...NONE.
VIZ001-200915-
SAINT THOMAS AND SAINT JOHN-
509 AM AST FRI DEC 19 2025
TODAY TONIGHT SAT
CLOUD COVER MCLEAR MCLEAR MCLEAR
PRECIP TYPE NONE SHOWERS SHOWERS
CHANCE PRECIP (%) 0 30 10
TEMP (24H TREND) 84 (-1) 72 (-4) 86
RH % (24H TREND) 61 (-6) 97 (+7) 59
WIND 20FT/EARLY(MPH) E 14 G18 E 13 G17 E 14 G19
WIND 20FT/LATE(MPH) E 14 G18 E 13 G17 E 14 G19
MIXING HGT(FT-AGL/MSL)3580 3450
TRANSPORT WND (MPH) E 17 E 20
VENT RATE (KT-FT) 53700 58650
DISPERSION 5 5
DSI 6 6 6
RH RECOVERY EXCELLENT
REMARKS...NONE.
VIZ002-200915-
ST CROIX-
509 AM AST FRI DEC 19 2025
TODAY TONIGHT SAT
CLOUD COVER MCLEAR MCLEAR MCLEAR
PRECIP TYPE SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 10 30 20
TEMP (24H TREND) 84 (-1) 72 (-3) 85
RH % (24H TREND) 63 (-5) 94 (+5) 62
WIND 20FT/EARLY(MPH) E 13 G17 NE 13 E 14 G18
WIND 20FT/LATE(MPH) E 13 G17 NE 13 E 14 G18
MIXING HGT(FT-AGL/MSL)4020 3940
TRANSPORT WND (MPH) E 20 E 21
VENT RATE (KT-FT) 68340 70920
DISPERSION 5 5
DSI 6 6 6
RH RECOVERY EXCELLENT
REMARKS...NONE.
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