June 2009 Climate Report for Puerto Rico and the U.S. Virgin Islands

 

June 2009 Highlights:

 

 

Temperatures across Puerto Rico ranged from 56ºF in Adjuntas on both the 1st and 28th of June to 96ºF in Rio Piedras on both the 26th and 28th of June. Temperatures across the U.S. Virgin Islands ranged from 68ºF at Beth Upper New Works on Saint Croix, observed on June 1st and 29th, to 91ºF, also at Beth Upper New Works on Saint Croix, observed on June 29th. Other notable temperatures for June 2009 are listed below:
 

Other Notable June 2009 High Temps:            
 
95ºF in Corozal on June 28th
95ºF in Ponce on June 1st
93ºF in Trujuillo Alto on Jun 28th
93ºF in Manati on June 28th
93ºF in Mayaguez on June 26th & 28th
93ºF in San Juan on June 27th
93ºF in Lajas on June 26th
 
Other Notable June 2009 Low Temps:
 
59ºF in Corro Maravilla on June 11th   
59ºF in Toro Negro on June 29th
62ºF in Maricao on June 1st
62ºF in Aibonito on June 22nd & 29th   
65ºF in Trujillo Alto on June 9th
 
 

 
The highest 24-hour precipitation total for the month of June was 4.65”, which fell in Jajome Alto on June 3rd. The highest weekly rainfall total occurred at Paraiso where 5.67” of rainfall accumulated the week ending June 12th.

 

 

 Figure 1A – Island wide precipitation forJanuary-June 2009

 

 

 

Figure 1B – Graphical Display of June 2009 precipitation across Puerto Rico and the U.S. Virgin Islands derived from a combination of rain gage and radar data.

 

 

 

Monthly Weather Summary:
 
June 2009 turned out to be the second wettest June on record at San Juan International Airport, indicative of continued deep moisture transport and general troughiness over the area. Normally, June is a transition between the normally wet month of May, and drier weather before the meat of hurricane season begins late in August. This was not the case in 2009. A very deep and persistent trough continued over the Southwestern Atlantic and Eastern Caribbean, promoting a constant flow of moist tropical air over the region. The subtropical high was displaced further east and north, and weaker than typical for this time of year, allow for low pressure troughs and tropical waves to freely move over the region. Another factor keeping June very moist was the lack of Saharan dust which typically moves over the Tropical Atlantic and Eastern Caribbean by early June, acting to dry and stabilize the air mass. In 2009, the Saharan Dust did not get going until late in June, at which point San Juan had already logged nearly 10 inches of rain. Another factor making it seem like a month of never ending rain, especially for the San Juan area, was the persistence of streamers, or lines of showers which form downwind of the U.S. Virgin Islands and the El Yunque Mountains of Puerto Rico. In the ample tropical moisture, and favorable mean east to southeasterly wind flow, several streamers reached Eastern Puerto Rico, and specifically the San Juan metropolitan area, bringing heavy rains to millions of residents. By late June, the deep troughiness of the Southwestern Atlantic began to fill in and a more typical subtropical high pressure regime, with Saharan Dust over the Atlantic began to build. This dried out the widespread heavy rains, and shifted shower and thunderstorm activity to a more typical pattern of daily activity confined to western portions of Puerto Rico.
 
June 2009 Statistics:
 
Average June Temperatures/Precipitation (NCDC 1971-2000 averages):
 

 
High:     
Low:     
AvgT:   
Pcpn:      
San Juan              
87.6ºF
76.6ºF    
82.1ºF
3.52”
Saint Thomas
89.5ºF    
77.4ºF    
83.5ºF
2.35”
Saint Croix
88.6ºF
78.1ºF
83.4ºF
2.30”

 
June 2009 Observations:
 

 
High:     
Low:     
AvgT:   
Pcpn:      
San Juan
90.4ºF     (+2.8ºF)
77.6ºF     (+1.0ºF) 
84.0ºF     (+1.9ºF) 
4.04”       (0.52”)  
Saint Thomas
87.4ºF     (-2.1ºF)  
78.1ºF     (0.7ºF)   
82.8ºF     (-0.7ºF)  
1.15”       (-1.20”) 
Saint Croix
87.5ºF     (-1.1ºF)
77.6ºF     (-0.5ºF)
82.6ºF     (-0.8ºF)
1.61”       (-0.69”)

 
June 2009 Extremes:
 

 
High:  
Low:  
San Juan
94ºF – June 10th    
74ºF – June 1st
Saint Thomas
91ºF – June 21st & 28th
74ºF – June 23rd
Saint Croix
89ºF – June 26th & 30th
73ºF – June 1st

 
June Historical Statistics:
 
Highest June Temperatures on record:
 

San Juan              
97ºF – June 5th, 1988*
*Most recent occurrence
Saint Thomas      
99ºF – June 23rd, 1996
98ºF – June 29th, 2980*
*Most recent occurrence
Saint Croix
98ºF – June 18th, 1993
95ºF – June 23rd & 24th, 1972

 
Lowest June Temperatures on record:
 

San Juan              
69ºF – June 20th, 1956 &
           June 1st, 1957
70ºF – June 6th, 1964*
*Most recent occurrence
Saint Thomas
67ºF – June 20th & 21st, 1972
68ºF – June 1st, 1974            
69ºF – June 22nd, 1981*
*Most recent occurrence
Saint Croix
66ºF – June 28th, 1979
67ºF – June 12th, 1954
68ºF – June 26th, 1953

 
Wettest Junes:
 

San Juan              
10.96” June 1965
10.37” June 2009
 9.32” June 1958
Saint Thomas      
8.29”   June 1956
6.97”   June 1983
5.33”   June 2009
Saint Croix
7.83” June 1987
6.34” June 1979
4.78” June 1960

 
Driest Junes:
 

San Juan              
0.29” June 1985
0.98” June 1997
1.24” June 1971
Saint Thomas
0.07” June 2007
0.18” June 2003
0.28” June 1989
Saint Croix
0.10” June 2001
0.12” June 1985
0.49” June 2003

 

 

2000-2009 Decade in Review:
 
Decadal Observations for San Juan, Puerto Rico:
 
Decadal June High Temperatures:

2000’s
 
1990’s
 
1980’s
 
1970’s
 
1960’s
 
1950’s*
88.9ºF
 
88.9ºF
 
89.7ºF
 
88.6ºF
 
87.4ºF
 
87.3ºF

 
Decadal June Low Temperatures:

2000’s
 
1990’s
 
1980’s
 
1970’s
 
1960’s
 
1950’s*
77.0ºF
 
76.7ºF
 
76.6ºF
 
76.8ºF
 
74.5ºF
 
73.3ºF

 
Decadal June Average Temperatures:

2000’s
 
1990’s
 
1980’s
 
1970’s
 
1960’s
 
1950’s*
83.0ºF
 
82.8ºF
 
83.2ºF
 
82.7ºF
 
80.9ºF
 
80.3ºF

 
Decadal June Precipitation:

2000’s
 
1990’s
 
1980’s
 
1970’s
 
1960’s
 
1950’s*
4.71”
 
4.30”
 
3.41”
 
3.48”
 
5.27”
 
7.04”

* Records for San Juan began on January 1st, 1956

 

 

 

 Figure 2 – Temperature deviations for San Juan, PR 

 

 

 

 Figure 3 – Temperature deviations for Saint Thomas, VI

 

 

 

 Figure 4 – Temperature deviations for Saint Croix, VI

 

 

Figure 5 – June precipitation deviations 2000s

 

 

 

 

Figure 6 – Year-to-data precipitation deviations for San Juan, Saint Thomas, and Saint Croix 

 

Looking ahead toward the month of July:
 
Average July Temperatures/Precipitation (NCDC 1971-2000 averages):
 

 
High:     
Low:     
AvgT:   
Pcpn:      
San Juan              
87.4ºF
76.9ºF    
82.2ºF
4.16”
Saint Thomas
90.4ºF    
77.8ºF    
84.1ºF
2.42”
Saint Croix
89.3ºF
78.0ºF
83.7ºF
2.79”

 
 
Moon/Sun/Tide Data for the month of July:
 
                The sun rises at 5:52 am AST on the 1st of July and sets at 7:05 pm AST, in San Juan, Puerto Rico. This represents a total of 13 hours and 13 minutes of daylight. By July 31st, the sun will rise at 6:02 am AST and set at 7:00 pm AST, providing a total of 12 hours and 58 minutes of daylight, or a total decrease of 15 minutes over the course of the month. At Charlotte Amalie on Saint Thomas, the sun will rise at 5:47 am AST and set at 7:00 pm AST on the 1st of the month. By the end of the month, the sun will rise at 5:57 am AST and set at 6:55 pm AST, also representing a total decrease of 15 minutes of daylight for the month.
 
                For the month of July, a full moon will be observed on the 7th of the month at 5:21 am AST. There will also be a new moon on the 2125 of the month at 10:35 pm AST. The first quarter of the moon was observed on June 29th and the last quarter of the moon will be observed on the July 15th.
 
                Links to additional sunrise/sunset data, phases of the moon, as well as tide data can all be found by clicking on the climate link of the National Weather Service San Juan homepage (www.srh.noaa.gov/sju) and then clicking on the Astronomical tab.

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