Climate and Hydrology Monthly Report
for Puerto Rico and the US Virgin Islands
Valid October 2023
Issued By: WFO San Juan, PR
Contact Information: [email protected]ov
National Weather Service
San Juan
SUN MON TUE WED THU FRI SAT
1
89
2
90
3
90
4
89
5
95
6
94
7
95
79
1.54”
82
0.25”
81
0.18”
79
0.20”
80
0.01”
82
0.00”
82
0.00”
8
95
9
96
10
92
11
91
12
91
13
91
14
92
78
0.00”
81
0.00”
81
0.00”
79
0.00”
81
0.00”
81
0.00”
81
0.00
15
96
16
96
17
92
18
92
19
90
20
90
21
89
81
0.58”
82
0.00”
79
0.01”
79
0.00”
81
0.00”
80
0.09”
80
0.00”
22
87
23
91
24
89
25
88
26
88
27
86
28
91
78
0.40”
79
0.18”
81
0.08”
77
0.33”
77
0.56”
77
5.20”
78
0.05”
29
90
30
85
31
92
78
0.08”
79
0.00”
79
0.00”
October Monthly Summary
Highest: 96 on the 15, 16
th
Lowest: 77 on the 26, 27
th
Average: 85.4
Rain Total: 9.73”
Days above 90: 22
Lows above 80: 16
Days with Rain (>0.01”): 15
Rankings:
1
st
warmest
8
th
wettest
Remarks:
4
th
warmest month overall
Wettest day of any October on the 28
th
Luis Muñoz Marín International Airport Climate Summary
National Weather Service
San Juan
October Monthly Summary:
Highest: 94 on the 1, 2
nd
Lowest: 77 on the 3
rd
Average: 85.6
Rain Total: 9.92”
Days above 90: 27
Lows above 80: 22
Days with Rain (>0.01”): At least 15
Rankings:
1
st
warmest
Remarks:
6
th
warmest month overall
*Underline amounts represent 3-day
accumulation
Rain total from COOP back-up site
Henry E. Rohlsen International Airport Climate Summary
SUN MON TUE WED THU FRI SAT
1
94
2
94
3
91
4
89
5
92
6
92
7
92
80
0.01”
81
0.66”
77
0.13”
80
3.85”
81
0.19”
83
0.26”
81
0.00”
8
93
9
92
10
91
11
92
12
92
13
91
14
91
80
0.00”
81
0.00”
79
0.00”
79
0.00”
80
0.35”
80
0.00”
80
0.00
15
92
16
91
17
92
18
93
19
93
20
93
21
90
79
0.00
81
0.00”
80
0.00”
81
0.00”
81
0.00”
82
0.04”
80
0.00”
22
91
23
91
24
90
25
91
26
89
27
90
28
88
81
0.00”
80
0.24”
81
0.03”
79
0.37”
78
0.14”
79
0.69”
79
0.00”
29
90
30
87
31
90
80
0.00”
80
2.81”
80
0.15”
National Weather Service
San Juan
October Monthly Summary:
Highest: 91 on the 12, 19
th
Lowest: 75 on the 30
th
Average: 83.7
Rain Total: 8.69”
Days above 90: 5
Lows above 80: 13
Days with Rain: 20
Rankings:
10
th
warmest
23
rd
wettest
Remarks:
None.
Cyril E. King International Airport Climate Summary
SUN MON TUE WED THU FRI SAT
1
91
2
90
3
90
4
86
5
88
6
88
7
88
79
0.78”
83
0.02”
79
0.53”
77
2.00”
79
0.70”
83
0.00”
82
0.00”
8
89
9
89
10
88
11
89
12
91
13
88
14
87
81
0.01”
78
0.02”
80
0.00”
80
0.00”
80
0.53”
79
0.00”
79
0.46
15
87
16
88
17
88
18
88
19
91
20
89
21
87
80
0.00”
82
0.00”
81
0.00”
79
0.01”
78
0.39”
81
0.20”
78
0.31”
22
87
23
88
24
89
25
89
26
87
27
86
28
85
78
0.34”
82
0.00”
79
0.28”
80
0.08”
79
0.00”
76
1.40”
78
0.00”
29
86
30
85
31
87
78
0.33”
75
0.11”
79
0.19”
National Weather Service
San Juan
Observed Temperature
● Temperatures across the local sites have been
mostly above normal. The highest 1- day
maximum temperature reported across the
local sites was: Guayama 1SW with 97°F
Image Captions:
Left - Observed Temperature for Puerto Rico and US Virgin Islands (COOP)
Right - Departure from normal temperature for Puerto Rico and US Virgin Islands (COOP)
Data Courtesy High Plains Regional Climate Center/NWS COOP Stations.
Data over the past 30 days ending November 01, 2023
Link to generate the latest ACIS Climate Maps
National Weather Service
San Juan
● Rainfall patterns during the last month has been mostly
above normal for eastern Puerto Rico and the USVI, and
below normal for most stations along western Puerto Rico.
The site that received the most rain was: East End, St. John
with 21.50”
Image Captions:
Left - Observed Precipitation for Puerto Rico and US Virgin Islands (COOP & CoCoRaHS)
Right - Departure from normal Precipitation for Puerto Rico and US Virgin Islands (COOP &
CoCoRaHS)
Data Courtesy High Plains Regional Climate Center/NWS COOP Stations.
Data over the past 30 days ending November 01, 2023
Observed Rainfall
Link to generate the latest ACIS Climate Maps
National Weather Service
San Juan
Estimated Rainfall
● Over 10 inches of rainfall were
observed across the southeast and
east, Vieques, Culebra, and sections of
the San Juan metro area, central
interior and San Sebastian in the west.
● The rest of Puerto Rico mainly
observed 4 to 10 inches of rainfall,
with lesser amounts around Rincon
and Guanica and it surroundings.
● Rainfall amounts were also significant
for the U.S. Virgin Islands, generally
ranging from 5 to over 10 inches in
some spots.
● The main rain events were caused by
nearby Tropical Storm/Hurricane
Tammy and a trough by the latter part
of the month.
Image Captions:
Estimated Rainfall for the month of October. This
map is courtesy of the NWS SJU GIS Team.
Estimated Rainfall was obtained from AHPS, COOP and CoCoRaHS stations
National Weather Service
San Juan
Departure from Normal Rainfall
● Above normal precipitation was observed for
the east and southeast, as well as Vieques,
Culebra and portions of the San Juan metro
area and the extreme northwest coastal area.
● A rainfall deficit of 3 to more than 8 inches
was observed in the interior from Comerio
into the western coast of Puerto Rico.
Image Captions:
Estimated Departure from Normal Rainfall for Puerto Rico. This map
is courtesy of the NWS SJU GIS Team.
*AHPS does not provide rainfall departure from normal for the USVI.
Estimated Departure from normal was obtained from AHPS
National Weather Service
San Juan
Hydrologic Conditions and Impacts
● The 28-day average streamflow from the USGS river gauge
network indicates most streamflows running above to well
above normal across central and eastern Puerto Rico. This is
not the case across western areas of the island where
streamflows are running below or well below normal. For
Reservoir levels, click here.
● Widespread flooding was reported by the end of the month
mainly across the northern slopes of Puerto Rico, including
the San Juan Metro Area were 6 to 8 inches were observed
in a short period of time. Click here for Storm Data Reports
Image Caption: Monthly compared to historical streamflows
for Puerto Rico in October.
The latest soil monthly streamflow for Puerto Rico can be found on WaterWatch
Latest Monthly Average Streamflow from USGS
Non-Routine Hydrologic Products Issued Products issued for
the month
Hydrologic Outlooks (SJUESFSJU) 1
Flood Watches (SJUFFASJU) 2 (1 event)
Flood Warnings (SJUFLWSJU) 4
Flash Flood Warnings (SJUFFWSJU) 18
Flash Flood Statements (SJUFFSSJU) ~20
Urban/Small Stream Flood Advisories (SJUFLSSJU) 74
National Weather Service
San Juan
Soil Saturation
The latest soil moisture information for Puerto Rico can be found on PRAGWATER
Latest data retrieved from PRAGWATER indicated high soil saturation across the western interior, east and southeast, while
lower values are observed in the southern and northern plains and the eastern interior. The higher crop stress factor is
observed from Lajas to Peñuelas.
Image Caption: (Left) Crop Stress Factor for Puerto Rico. (Right) Root Zone Soil Saturation
Fraction.
National Weather Service
San Juan
U.S. Drought Monitor
Link to the latest U.S. Drought Monitor for the Caribbean
Image Caption: U.S. Drought Monitor valid 8am AST October 31st,.
DROUGHT CONDITIONS : Drought conditions continue
to prevail, although improving.
Drought intensity and Extent
○ D2 (Severe Drought): Severe Drought
conditions are now observed across Saint
Thomas and Saint Croix.
○ D1 (Moderate Drought): Moderate Drought
conditions are still observed at portions of
northwest Puerto Rico, mainly in the vicinity
of Lares, Utuado and Arecibo.
○ D0 (Abnormally Dry): Abnormally Dry
conditions are observed across most areas
of northern Puerto Rico.
National Weather Service
San Juan
Recent Change in Drought Intensity
Link to the latest 4-week change map for the Caribbean
Four Week Drought Monitor Class Change.
○ Drought Improved: Beneficial rains
this past month have provided
significant relief to drought on the
islands, particularly across the U.S.
Virgin Islands.
Image Caption: U.S. Drought Monitor 4-week change map valid 8am AST Nov 1st 2023.
National Weather Service
San Juan
Long-Range Precipitation Outlook
The latest monthly and seasonal outlooks can be found on the CPC homepage
● Latest long-range guidance indicated a
higher chance to observe rainfall near to
above normal. Therefore, the risk for
widespread flash flooding is normal to
above normal.
Image caption: NMME precipitation forecast issued October
2023.Valid through February 2024.
National Weather Service
San Juan
Long-Range Temperature Outlook
The latest three-months temperature outlook can be found on the CPC homepage
● Based on the North American
Multi-Model Ensemble (NMME), there
is a chance higher than 90% of
observing above normal temperature
for the period of November, December
& January.
Image caption: NMME temperature forecast issued October
2023. Valid through February 2024.
National Weather Service
San Juan
Long Range Drought Outlook
The latest monthly and seasonal outlooks can be found on the CPC homepage
● Based on the expected conditions, drought
conditions are expected to improve across
Puerto Rico and the US Virgin Islands.
Image Caption: U.S. Seasonal Drought Outlook Valid for
November 1 2023 - January 31, 2024.
