104
FNCA52 TJSJ 181930
FWFSJU
FIRE WEATHER PLANNING FORECAST FOR PUERTO RICO
NATIONAL WEATHER SERVICE SAN JUAN PR
330 PM AST MON MAY 18 2026
DISCUSSION
A SLIGHT INCREASE IN MOISTURE ON TUESDAY MAY PREVENT RH VALUES
FROM REMAINING ABOVE 55%; HOWEVER, RAINFALL SHOULD REMAIN LIMITED
ACROSS THE SOUTHERN PLAINS, ALLOWING RELATIVE HUMIDITY TO DROP TO
CRITICAL FIRE WEATHER THRESHOLDS IN THE REGION. ADDITIONALLY,
SUSTAINED WINDS OF 15 TO 20 MPH, WITH HIGHER GUSTS, COMBINED WITH
ELEVATED KBDI VALUES, WILL FAVOR THE RAPID SPREAD OF WILDFIRES
ACROSS THE SOUTHERN COASTAL PLAINS. THE LOW 7-DAY PERCENT OF
NORMAL RAINFALL WILL ALSO PERSIST ACROSS THE SOUTHEASTERN COASTAL
PLAINS. FIRE MANAGEMENT PARTNERS ARE URGED TO REMAIN VIGILANT.
PRZ014-190800-
SOUTHEAST COASTAL PLAINS-
330 PM AST MON MAY 18 2026
TONIGHT TUE TUE NIGHT WED
CLOUD COVER MCLEAR MCLEAR PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 10 20 20 30
TEMP (24H TREND) 71 (-3) 90 (+2) 72 89
RH % (24H TREND) 84 (-1) 48 (-4) 89 45
WIND 20FT/EARLY(MPH) E 14 E 16 E 12 E 16
WIND 20FT/LATE(MPH) NE 12 E 16 E 10 E 17
MIXING HGT(FT-AGL/MSL) 5260 5290
TRANSPORT WND (MPH) E 20 E 21
VENT RATE (KT-FT) 89420 95220
DISPERSION 5 5
DSI 5 6 4 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ015-190800-
SOUTHERN HILLS-
330 PM AST MON MAY 18 2026
TONIGHT TUE TUE NIGHT WED
CLOUD COVER MCLEAR MCLEAR MCLEAR PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 10 20 10 20
TEMP (24H TREND) 68 (-4) 86 (+3) 68 86
RH % (24H TREND) 95 (+4) 57 (-5) 97 59
WIND 20FT/EARLY(MPH) E 13 E 14 E 13 E 14
WIND 20FT/LATE(MPH) E 13 E 13 E 13 E 13
MIXING HGT(FT-AGL/MSL) 5920 5680
TRANSPORT WND (MPH) E 20 E 21
VENT RATE (KT-FT) 100640 102240
DISPERSION 5 5
DSI 3 6 3 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ016-190800-
NORTH COASTAL PLAINS-
330 PM AST MON MAY 18 2026
TONIGHT TUE TUE NIGHT WED
CLOUD COVER MCLEAR PCLDY PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 20 40 30 50
TEMP (24H TREND) 71 (-3) 90 (+2) 71 89
RH % (24H TREND) 94 (+1) 56 (-4) 98 57
WIND 20FT/EARLY(MPH) E 18 E 17 E 14 E 17
WIND 20FT/LATE(MPH) E 12 E 20 E 13 E 20
MIXING HGT(FT-AGL/MSL) 5610 5490
TRANSPORT WND (MPH) E 18 E 20
VENT RATE (KT-FT) 89760 93330
DISPERSION 5 5
DSI 5 6 6 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ017-190800-
NORTHERN HILLS-
330 PM AST MON MAY 18 2026
TONIGHT TUE TUE NIGHT WED
CLOUD COVER MCLEAR PCLDY MCLEAR PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS TSTMS
CHANCE PRECIP (%) 0 50 20 50
TEMP (24H TREND) 68 (-4) 88 (+1) 69 88
RH % (24H TREND) 94 (0) 57 (-3) 98 58
WIND 20FT/EARLY(MPH) E 16 E 14 E 12 E 14
WIND 20FT/LATE(MPH) E 9 E 18 E 10 E 18
MIXING HGT(FT-AGL/MSL) 6620 6110
TRANSPORT WND (MPH) E 16 E 17
VENT RATE (KT-FT) 92680 91650
DISPERSION 5 5
DSI 4 6 4 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ018-190800-
WEST COAST-
330 PM AST MON MAY 18 2026
TONIGHT TUE TUE NIGHT WED
CLOUD COVER MCLEAR PCLDY MCLEAR PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS TSTMS
CHANCE PRECIP (%) 10 30 10 30
TEMP (24H TREND) 71 (-2) 91 (+1) 72 91
RH % (24H TREND) 91 (-2) 55 (-6) 94 57
WIND 20FT/EARLY(MPH) E 11 E 14 E 11 E 14
WIND 20FT/LATE(MPH) E 11 E 16 E 12 E 16
MIXING HGT(FT-AGL/MSL) 5160 5510
TRANSPORT WND (MPH) E 14 E 14
VENT RATE (KT-FT) 61920 66120
DISPERSION 5 5
DSI 4 6 4 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ019-190800-
EASTERN INTERIOR-
330 PM AST MON MAY 18 2026
TONIGHT TUE TUE NIGHT WED
CLOUD COVER PCLDY PCLDY PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 30 40 30 40
TEMP (24H TREND) 69 (-4) 87 (+2) 69 87
RH % (24H TREND) 95 (+1) 59 (-2) 98 61
WIND 20FT/EARLY(MPH) E 16 E 17 E 14 E 17
WIND 20FT/LATE(MPH) E 14 E 17 E 14 E 14
MIXING HGT(FT-AGL/MSL) 5970 5630
TRANSPORT WND (MPH) E 20 E 20
VENT RATE (KT-FT) 101490 95710
DISPERSION 5 5
DSI 4 6 4 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ022-190800-
LUQUILLO MOUNTAIN RANGE-
330 PM AST MON MAY 18 2026
TONIGHT TUE TUE NIGHT WED
CLOUD COVER PCLDY PCLDY PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 40 40 30 50
TEMP (24H TREND) 67 (-4) 82 (+3) 67 82
RH % (24H TREND) 98 (+1) 66 (-3) 100 66
WIND 20FT/EARLY(MPH) E 13 E 16 E 11 E 13
WIND 20FT/LATE(MPH) E 12 E 14 E 11 E 12
MIXING HGT(FT-AGL/MSL) 4070 4370
TRANSPORT WND (MPH) E 20 E 20
VENT RATE (KT-FT) 69190 74290
DISPERSION 5 5
DSI 6 6 6 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ023-190800-
CENTRAL MOUNTAIN RANGE-
330 PM AST MON MAY 18 2026
TONIGHT TUE TUE NIGHT WED
CLOUD COVER MCLEAR PCLDY MCLEAR PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 0 50 10 40
TEMP (24H TREND) 65 (-4) 87 (+5) 66 87
RH % (24H TREND) 96 (+2) 58 (-7) 99 61
WIND 20FT/EARLY(MPH) E 9 E 10 E 9 E 10
WIND 20FT/LATE(MPH) E 8 E 10 E 9 E 10
MIXING HGT(FT-AGL/MSL) 7150 6390
TRANSPORT WND (MPH) E 16 E 16
VENT RATE (KT-FT) 100100 89460
DISPERSION 5 5
DSI 2 6 2 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ024-190800-
CAYEY MOUNTAIN RANGE-
330 PM AST MON MAY 18 2026
TONIGHT TUE TUE NIGHT WED
CLOUD COVER PCLDY PCLDY PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 30 30 40 40
TEMP (24H TREND) 68 (-3) 82 (+1) 68 82
RH % (24H TREND) 98 (0) 65 (-1) 100 66
WIND 20FT/EARLY(MPH) E 11 E 13 E 10 E 12
WIND 20FT/LATE(MPH) E 11 E 13 E 10 E 11
MIXING HGT(FT-AGL/MSL) 5030 5070
TRANSPORT WND (MPH) E 20 E 21
VENT RATE (KT-FT) 85510 91260
DISPERSION 5 5
DSI 5 6 4 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ025-190800-
VIEQUES-
330 PM AST MON MAY 18 2026
TONIGHT TUE TUE NIGHT WED
CLOUD COVER PCLDY PCLDY PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 30 40 40 50
TEMP (24H TREND) 74 (-2) 87 (+1) 74 87
RH % (24H TREND) 88 (-1) 61 (-1) 91 60
WIND 20FT/EARLY(MPH) E 18 E 19 E 18 E 19
WIND 20FT/LATE(MPH) E 18 E 18 E 18 E 17
MIXING HGT(FT-AGL/MSL) 3990 3950
TRANSPORT WND (MPH) E 22 E 23
VENT RATE (KT-FT) 75810 79000
DISPERSION 5 5
DSI 6 6 6 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ026-190800-
CULEBRA-
330 PM AST MON MAY 18 2026
TONIGHT TUE TUE NIGHT WED
CLOUD COVER PCLDY PCLDY PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 30 40 30 50
TEMP (24H TREND) 76 (-2) 89 (+2) 76 89
RH % (24H TREND) 87 (-1) 57 (-5) 90 57
WIND 20FT/EARLY(MPH) E 19 E 19 E 18 E 19
WIND 20FT/LATE(MPH) E 18 E 19 E 19 E 17
MIXING HGT(FT-AGL/MSL) 3920 3920
TRANSPORT WND (MPH) E 22 E 24
VENT RATE (KT-FT) 74480 82320
DISPERSION 5 5
DSI 6 6 6 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ027-190800-
SOUTHWEST COASTAL PLAINS AND MONA ISLAND-
330 PM AST MON MAY 18 2026
TONIGHT TUE TUE NIGHT WED
CLOUD COVER MCLEAR MCLEAR MCLEAR PCLDY
PRECIP TYPE SHOWERS SHOWERS NONE SHOWERS
CHANCE PRECIP (%) 0 10 0 10
TEMP (24H TREND) 72 (-3) 91 (+2) 73 91
RH % (24H TREND) 83 (-3) 46 (-8) 86 47
WIND 20FT/EARLY(MPH) E 16 E 19 E 17 E 20
WIND 20FT/LATE(MPH) E 16 SE 21 E 12 E 21
MIXING HGT(FT-AGL/MSL) 5270 5640
TRANSPORT WND (MPH) E 22 E 23
VENT RATE (KT-FT) 100130 112800
DISPERSION 5 5
DSI 5 6 4 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
VIZ001-190800-
SAINT THOMAS AND SAINT JOHN-
330 PM AST MON MAY 18 2026
TONIGHT TUE TUE NIGHT WED
CLOUD COVER MCLEAR PCLDY MCLEAR PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 20 40 20 40
TEMP (24H TREND) 75 (-3) 86 (+1) 75 86
RH % (24H TREND) 88 (+2) 62 (-2) 91 61
WIND 20FT/EARLY(MPH) E 19 E 19 E 19 E 20
WIND 20FT/LATE(MPH) E 18 E 19 E 19 E 17
MIXING HGT(FT-AGL/MSL) 3870 3820
TRANSPORT WND (MPH) E 25 E 25
VENT RATE (KT-FT) 85140 84040
DISPERSION 5 5
DSI 6 6 6 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
VIZ002-190800-
ST CROIX-
330 PM AST MON MAY 18 2026
TONIGHT TUE TUE NIGHT WED
CLOUD COVER MCLEAR PCLDY PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 20 30 20 40
TEMP (24H TREND) 75 (-2) 87 (+1) 75 87
RH % (24H TREND) 88 (0) 61 (-3) 92 61
WIND 20FT/EARLY(MPH) E 17 E 18 E 18 E 19
WIND 20FT/LATE(MPH) E 17 E 18 E 19 E 17
MIXING HGT(FT-AGL/MSL) 4580 4770
TRANSPORT WND (MPH) E 22 E 21
VENT RATE (KT-FT) 87020 85860
DISPERSION 5 5
DSI 6 6 6 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page