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October 04, 2010

Contact:                 John Fausett, NWS
                         (575) 589-4088 Ext. 223
WHAT:                    North American Monsoon Season Ends
WHEN:                    October 04, 2010
WHERE:                   Southern New Mexico and far west Texas
WHO:                     National Weather Service, Santa Teresa, New Mexico

                       MONSOON SEASON 2010 ENDED SEPTEMBER 30
                                                                           th                        th
The Monsoon Season, which is formally observed annually from June 15 through September 30 by the
National Weather Service offices in New Mexico, Arizona and southwest Texas, came to a close on
September 30. The actual monsoon pattern got off to a slow, sporadic start this year in southern New
Mexico and far west Texas in late June with only around 33% of areal coverage of precipitation. July
turned out to be very active with nearly 90% areal coverage. August saw some breaks in the precipitation
with the overall intensity and areal coverage down somewhat. September ended the season on a fairly
active level. The 2010 Monsoon was one of considerable variability in both space and time in southern
New Mexico and far West Texas. The overall behavior of the monsoon was strongly influenced by the
strong subtropical ridge of high pressure aloft which would oscillate back and forth into New Mexico at
times, suppressing convection and providing some 30 100+ degree days in El Paso (twice the normal
value). Due to the position of the upper ridge, convection was often biased to the western slopes of local
mountains. Lack of vertical wind shear aloft along with a very moist subtropical air mass (surface dew
points often in the 60 to 65 F range) frequently resulted in storms that produced torrential flooding
downpours in a short period of time. The El Paso International Airport received 4.08 inches of rainfall
during the 2010 monsoon which is 79.4% of the normal amount of 5.14 inches. However, New Mexico
State University in Las Cruces measured 7.32 inches, and parts of west El Paso and Santa Teresa
exceeded 7 inches. In general, the North American Monsoon contributes around 50% of the annual
precipitation in the Borderland.

Some highlights to the season in southern New Mexico and far west Texas are as follows:

        June 05 --- El Paso International Airport reached 106 F setting a record high temperature for the
        June 06 --- 110 F set a new record for the date along with a trace of precipitation at the El Paso
        International Airport. 113 F was recorded in NE El Paso (ENVT2) with a 58 mph wind gust and
        .03 inches of rain. An 84 mph wind gust was recorded at McGregor Range in Otero County, NM
        injuring 4 soldiers when their field tent collapsed.
        June 28 --- A 62 mph wind gust and 1.2 inches of rain was reported in NE El Paso (ENVT2).
        July 11-12 ---Heavy rain overnight dumped rainfall amounts of 2.26 and 2.83 inches in the Santa
        Teresa, NM area with 2.80 recorded at KEPZ (El Paso WFO). Over 4 inches of rain fell near
        Anthony, TX. High water flooded West Canal Road Bridge in Hatch, NM. In the Radium Springs
        and Rincon areas, floodwaters moved cars off the road near Highway 187 and Santiago Peak
        July 19 ---Straight line thunderstorm outflow winds reached near 90 mph and produced damage
        to two mobile homes and destroyed a barn in the Gila, NM area of Grant County.
        July 14 ---1 inch of rain was reported in 20 minutes at Sixteen Springs in the southern
        Sacramento Mountains of Otero County, NM.
        July 25-26 ---New Mexico State University located in Las Cruces, NM reported 3.36 inches
        in a flash flood event during the night time hours. This set a record 24 hour rainfall amount for this
        cooperative station. There were at least 2 sites in Las Cruces reporting over 2 inches of rainfall in
        an hour or less. This event produced considerable flooding of streets, buildings, and homes.
        July 25-26 ---Torrential rains in Sierra County, NM near Truth or Consequences flooded streets
        and buildings. Also in Sierra county, 1.3 inches of rain fell at Poverty Creek in an hour.
       July 28 ---2.02 inches of rain was reported at McGregor Range in Otero County, NM.
       July 29 ---1.50 inches of rain fell in 30 minutes 6 miles north of Silver City in Grant County, NM
       while other storms caused flooding near the intersection of Highways 9 and 11 near Columbus in
       Luna County, NM.
       July 30 ---2.00 inches of rain in a short period of time caused flooding in Dell City in Hudspeth
       County, TX.
       July 31 ---12.21 inches of rain was recorded for the month of July at Cloudcroft, NM in the
       Southern Sacramento Mountains. This is more than double their average for July.
       August 1 --- Six tenths of an inch of rain was reported in 30 minutes in Silver City, NM.
       August 4 --- 1 inch of rain fell in 20 minutes at Poverty Creek in Sierra County, NM.
       August 12 ---A 65 mph wind gust was reported on the eastern mesa of Las Cruces, NM.
       August 16-17 --- 4 inches of rainfall was reported over a 2 day period 21 miles west of Silver
       City, in Grant county NM.
       September 15---Quarter to golf ball size hail was reported in eastern El Paso during the early
       evening hours. Interestingly, the worst hailstorm in El Paso’s history was nearly one year to the
       day and in the same location (east El Paso on September 16, 2009 producing $150 million in
       September 23 --- 2.03 inches of rain was reported in eastern El Paso.

This summary was compiled by David J. Novlan, Climate Focal Point at the El Paso WFO.

Although monsoon season ended formally on September 30, do not forget that several notable and very
dangerous severe weather and flash flood events have occurred in October across southern New Mexico
and far west Texas. Preparedness information for adverse weather can be found at


News media and emergency managers or anyone needing assistance in severe thunderstorm,
tornado and flash flood safety preparedness and planning are invited to contact one of the
following offices for details:

Southern New Mexico (Dona Ana, Grants, Hidalgo, Luna, Otero and Sierra Counties)
Far west Texas (El Paso and Hudspeth Counties)
John Fausett - Warning Coordination Meteorologist (NWS El Paso office)
(575) 589-4088 Ext. 223

Northern and Eastern New Mexico...
Kerry Jones – Warning Coordination Meteorologist (NWS Albuquerque office)
(505) 244-9149 Ext. 223

Southeastern New Mexico... Lea and Eddy Counties
Pat Vesper - Warning Coordination Meteorologist (NWS Midland, TX office)
(432) 563-5901 Ext. 223

On the web:

Information on New Mexico for your local NOAA National Weather Service Offices: (includes far west Texas)

Community Preparedness Recognition as a StormReady Community or StormReady Supporter:

Winter and other seasonal outlooks:

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