June 2010 Climate Report

June 2010 Climate Report for Puerto Rico and the U.S. Virgin Islands

June 2010 Highlights:

Temperatures across Puerto Rico ranged from 57ºF in Adjuntas on the 6^th of June to 96ºF in both Borinquen and Gurabo on June 27^th and 28^th respectively. Temperatures across the U.S. Virgin Islands ranged from 73ºF, June 25^th at Christiansted Airport on Saint Croix, to 94ºF, recorded at the Cyril E. King Airport on Saint Thomas June 16^th. Other notable temperatures for June 2010 are listed below:

Other Notable June 2010 High’s:

95ºF in Lajas on June 20^th

94ºF in Ponce on June 13^th

94ºF in Juncos on June 13^th

93ºF at Dos Bocas on June 11^th

93ºF at Guayama on June 19^th

92ºF in San Juan and Trujillo Alto

Other Notable June 2010 Low’s:

64ºF in Aibonito on June 26^th

65ºF in Toro Negro on June 28^th

66ºF in Maricao on June 28^th

67ºF in Arecibo on June 14^th

67ºF in Ponce on June20^th

67ºF in Lajas on June 16^th

^{*If multiple occurrences, all dates above reflect the latest occurrence of the month.}

The highest 24-hour precipitation total across Puerto Rico for the month of June was 5.11”, which fell in Trujillo Alto over the 24 hour period ending at 8am June 15^th. The highest weekly rainfall across Puerto Rico occurred in San Lorenzo, where 10.55” of rain accumulated the week ending June 25^th. Across the U.S. Virgin Islands, the highest 24-hour precipitation total fell at the Christiansted Airport on Saint Croix, where a record 3.94” fell over the 24 hour period ending at midnight on June 20^th. For the week ending June 25^th, 6.91” of rain fell at the Cyril E. King Airport on Saint Thomas, representing the highest weekly rainfall across the U.S. Virgin Islands for the month of June.

Graphical display of precipitation across Puerto Rico from January 2nd, 2010 through July 2nd, 2010

Figure 1A – Island wide averaged precipitation (and normals) - by week - for the weeks beginning on January 2nd and ending on July 2nd, 2010

June 2010 Rainfall composite using Radar and Rain Gage Data

Figure 1B – Graphical Display of June 2010 precipitation across Puerto Rico and the U.S. Virgin Islands derived from a combination of rain gage and radar data.

Monthly Weather Summary:

June 2010 began with hazy skies and limited shower activity across the local islands as a result of an upper level ridge and Saharan air moving across the region. This fair weather pattern across the local region prevailed through June 3^rd, when an upper level disturbance and a low level trough increased shower and thunderstorm activity across Puerto Rico and the U.S. Virgin Islands. Afterwards, a serial of tropical waves began to approach the regional waters. After June 8^th, tropical waves and upper level troughs dominated the weather pattern, producing widespread showers and thunderstorms across the local islands. By the end of the month, the widespread heavy rains dried out, and shower and thunderstorm activity shifted to a more typical pattern of daily activity confined mostly to western portions of Puerto Rico.

Normally, June is a transition between the wet month of May, and the drier weather typically observed before the peak of hurricane season. This was not the case in 2010. Statistically, June 2010 was well above normal, in terms of precipitation. At the Luis Muñoz Marin International Airport in San Juan, the monthly precipitation total was nearly half a foot above normal (5.71”), which accounted for the 6^th wettest June on record. Across the U.S. Virgin Islands, precipitation was also well above normal, with the wettest June on record occurring at the Cyril E. King Airport on Saint Thomas and the second wettest June on record occurring at the Christiansted Airport on Saint Croix.

In terms of temperature, 2010 has been an unusually warm year across the northeastern Caribbean, with the average temperature in San Juan running approximately one degree above normal every single month of 2010. The highest monthly temperature in San Juan was 92 degrees on June 7^th, and the low temperature fell to 74 degrees on both June 20^th and June 23^rd. At the end of the month, the average temperature was 0.6 degrees above normal, which marked the 13^th consecutive month of above normal temperatures in San Juan.

June 2010 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

89.5 ºF

77.4ºF

83.5ºF

2.35”

Saint Croix

88.6ºF

78.1ºF

83.4ºF

2.30”

June 2010 Observations:

High:

Low:

AvgT:

Pcpn:

San Juan

87.8ºF    (+0.2ºF)

77.5ºF    (+0.9ºF)

82.7ºF    (+0.6ºF)

9.23”      (+5.71”)

Saint Thomas

88.3ºF    (-1.2ºF)

79.4ºF    (+2.0ºF)

83.8ºF    (+0.3ºF)

9.51”      (+7.16”)

Saint Croix

88.4ºF    (-0.2ºF)

78.0ºF    (-0.1ºF)

83.2ºF    (-0.2ºF)

7.03”      (+2.38”)

June 2010 Extremes:

High:

Low:

San Juan

92ºF – June3^rd & 7^th

74ºF – June 20^th & 23^rd

Saint Thomas

94ºF – June16^th

75ºF – June 20^th & 25^th

Saint Croix

92ºF – June 9^th

73ºF – June 23^rd & 25^th

June Historical Statistics:

Highest June Temperatures on record:

San Juan

97ºF – June 5^th, 1988 & June 22^nd, 23^rd & 25^th, 1983

96ºF – June 27^th, 1988*

*Most recent occurrence

Saint Thomas

99ºF – June 23^rd, 1996

98ºF – June 29^th, 1980*

*Most recent occurrence

Saint Croix

97ºF – June 18^th, 1993

95ºF – June 24^th, 1972

94ºF – June 2^nd, 1972

Lowest June Temperatures on record:

San Juan

69ºF – June 1^st, 1957 & June 20^th, 1956

70ºF – June 6^th, 1964*

*Most recent occurrence

Saint Thomas

67ºF – June 20^th & 21^st, 1972

68ºF – June 1^st, 1974

69ºF – June 22^nd, 1981*

*Most recent occurrence

Saint Croix

66ºF – June 28^th, 1979

67ºF – June 12^th, 1954

68ºF – June 26^th, 1953

Wettest Junes:

San Juan

10.96” June 1965

10.37” June 2009

9.32” June 1958

Saint Thomas

9.51” June 1960

8.29” June 1956

6.97” June 1983

Saint Croix

7.83” June 1987

7.03” June 2010

6.34” June 1979

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

2000-2010 Decade in Review:

June 2010 marked the 13^th consecutive month of above normal temperatures in San Juan. June 2010 was also the 6th wettest June on record in San Juan and ranked as the wettest June on record at Cyril E. King Airport on Saint Thomas and the second wettest at the Christiansted Airport on Saint Croix. This was in large part due to a very strong early season tropical wave that broke numerous precipitation records across Puerto Rico and the US Virgin Islands during the middle of the month. In fact, 2010 has generally been a very wet year to date across Puerto Rico, so far ranking as the wettest start to a year since record keeping began in San Juan. For a look at temperature and precipitation deviations for San Juan, Saint Thomas and Saint Croix from their NCDC averages, see Figures 2 to 6 below. A summary of June 2010 data for San Juan along with the previous 6 decades of data from San Juan has also been included below.

Decadal Observations for San Juan, Puerto Rico:

Decadal June High Temperatures:

2010	2000’s	1990’s	1980’s	1970’s	1960’s	1950’s
*87.8ºF*	*88.9ºF*	*88.9ºF*	*89.7ºF*	*88.6ºF*	*87.4ºF*	*87.3ºF*

Decadal June Low Temperatures:

2010	2000’s	1990’s	1980’s	1970’s	1960’s	1950’s
*77.5ºF*	*77.0ºF*	*76.7ºF*	*76.6ºF*	*76.8ºF*	*74.5ºF*	*73.3ºF*

Decadal June Average Temperatures:

2010	2000’s	1990’s	1980’s	1970’s	1960’s	1950’s
*82.7ºF*	*83.0ºF*	*82.8ºF*	*83.2ºF*	*82.7ºF*	*80.9ºF*	*80.3ºF*

Decadal June Precipitation:

2010	2000’s	1990’s	1980’s	1970’s	1960’s	1950’s
*9.23”*	*4.71”*	*4.30”*	*3.41”*	*3.48”*	*5.27”*	*7.04”*

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

San Juan Temperature deviations for the month of June since 2000

Figure 2 - Temperature deviations for San Juan, PR

Saint Thomas USVI temperature deviations for the month of June since 2000

Figure 3 - Temperature deviations for Saint Thomas, VI

Saint Croix USVI temperature deviations for the month of June since 2000

Figure 4 - Temperature deviations for Saint Croix, VI

Precipitation deviations for the USVI and San Juan, PR for the month of June since 2000

Figure 5 - June 2000's precipitation deviations from normal

Year to date percent of normal precipitation for San Juan, PR and the USVI

Figure 6 - January - June 2010 precipitation deviations for San Juan, Saint Thomas, and Saint Croix

Looking ahead toward the month of July:

Looking ahead, July is the 6th driest month across Puerto Rico, with the Luis Muñoz International Airport in San Juan receiving 4.16” of rainfall on average. A record 9.35” of rain fell in July 1961 and the driest July on record was July 1974, when only 1.12” of rainfall was recorded in San Juan. The average high temperature at the Luis Muñoz International Airport in San Juan for July is 82.2 ºF, making July the 2^nd warmest month of the year, second only to August. Presently, we are experiencing ENSO-neutral conditions with a La Niña Watch now in effect.

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.pdf

This transition has an impact on expectations for the hurricane season, with NOAA currently forecasting a 95% of a near or above normally active hurricane season.

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 and sets at 7:05 pm AST, in San Juan, Puerto Rico on July 1^st. This represents a total of 13 hours and 13 minutes of daylight. By July 31^st, 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 in 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 1^st 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, representing a total decrease in daylight of 15 minutes over the course of the month.

For the month of July, a full moon will be observed on the 25^th of the month at 9:37 pm AST. There will also be a new moon on the 11^th of the month at 3:40 pm AST. The last quarter of the moon will be observed on the 4^th of July and the first quarter of the new moon will be observed on the 18^th of the month.

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.

National Weather Service Weather Forecast Office