August 10-11, 2013: Heavy Rainfall Impacts Southern Roosevelt County

An upper level ridge of high pressure over West Texas provided deep southerly flow over much of New Mexico.  The graphic below is the Water Vapor satellite image valid at 501am August 11, 2013.  Blueish shades indicate abundant mid and upper level moisture while reddish shades indicate very dry air.  The yellow streamlines in the graphic illustrate the atmosperic trajectories of air parcels around the ridge of high pressure.  This pattern allows abundant atmospheric moisture to stream west and north out of the Gulf of Mexico into Texas and New Mexico.  Meanwhile, a weak upper level disturbance noted by the red L symbol over south central New Mexico shifted northeast into Roosevelt County.  The combination of deep atmospheric moisture in place and instability approaching from the west allowed a stationary band of heavy showers and thunderstorms to develop over Roosevelt County.  The 24-hour rainfall amounts in association with this complex of thunderstorms were extreme, but were they records for New Mexico?

 satellite

 

 The radar loop below illustrates the extent of the showers and thunderstorms that trained over southern Roosevelt County between 1048 pm on the 10th and 506 am on the 11th.

Roosevelt County Radar Loop 

 

The National Weather Service recently upgraded all Doppler radars to dual polarization technology.  Precipitation estimates using this new technology have been shown in many cases to perform significantly better than the previous legacy Doppler system.  National Weather Service meteorologists still have access to the legacy data to make comparisons and provide the best possible estimates.  The two images below are storm total precipitation accumulations from the dual-polarization and legacy systems.  The first noticeable difference is that of resolution.  Additionally, the dual-polization technology showed higher storm total accumulation values than the legacy system.  

dual pol accum

 Dual-Polarization Storm Total Precipitation Accumulation Product ending at 800am August 11, 2013.

legacy total

 Legacy Doppler Radar Storm Total Precipitation Product ending at 800am August 11, 2013.

According to radar estimates, the area near Lingo received the greatest amount of precipitation.  However, the National Weather Service does not have any rain gages in Lingo to verify rainfall amounts.  We do know, however, there was no flooding reported. The table below lists some 24-hr rainfall totals from southern Roosevelt County.

LOCATION RAINFALL TOTALS (inches)
 Pep 7 SSE 5.10
Lingo 2 E 4.50
Lingo 2 S 3.50
Pep 6 SE 3.10
Milnesand 4 E 2.39
Elida 1.99

While these rainfall totals are very impressive for a 24-hr period, they are not records.  Below are provisional 24-hr precipitation extremes for various locations across New Mexico.  Weather observations are no longer recorded at several of the locations.  The record of nearly one foot of precipitation at Lake Maloya was observed on May 5, 1955.  There is no official record of this amount other than that found in a local printed archive of observations at the NWS office.  Pearl, NM, which was located a few miles west of Hobbs, NM received 10.53 inches, and this is the official highest 24-hr precipitation record found at NCDC for NM.  

LOCATION RAINFALL TOTALS (inches) DATE
Lake Maloya 11.28 May 5, 1955
Pearl 10.53 July 21, 1975
Porter 9.91 October 11, 1923
Black Lake 9.65 July 2, 1942
Hobbs 7.50 September 15, 1995
Elida 7.26 August 20, 2002

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