September 2015 summary - A Second Dry Monsoon Month

September just never got the memo that fall was supposed to be on its way. There were a couple of cooler periods during the month but most of the month ran above average... or well above average. In fact the highest temperature on the Sev came on Sep 27th. The refuge-wide average daily high temperature only ran below normal on 3 days during the month. While the seemingly relentless high temperatures were probably most noticeable, it was the overnight low temperatures that set a new record, running an average of 4.2 degrees F warmer than normal. The daily highs and the daily mean temperatures actually came in cooler than 2010, 2000 and 1998. Curiously enough no new daily record high temperatures was set during the month. The lowest minimum temperature during the month was 22 degrees F warmer than the record for the month.

    September Record Temperatures - High 37.6 (98.1 F), Low -3.3 (26.1 F)
    September '15 Record Temperatures - High 34.1 (93.4 F), Low 7.1 (48.4 F)

I thought my recent Met Central plea for moisture was going to be answered when a dying tropical depression in eastern Pacific pushed some moisture into the southwest on Sep 21-22. Arizona, and western NM got more benefit from this moisture. This moisture did push the September totals for the Sev out of the basement but came nowhere near pushing the monthly total close to normal. This is the driest September since 2001 and the 4th driest in the past 26 years. 2000 was the driest Sep with 2001 and 1993 running 2nd and 3rd.

September Meteorological Summary

                      September    September '15     September '15
Variable             Long-term* Mean    Mean           Mean Range
Mean Max Temp (C)         28.42          30.5          28.1 - 31.5
Mean Min Temp (C)         12.63          14.7          12.5 - 16.0
Mean Average Temp (C)     20.52          22.6          20.8 - 23.6
Mean R.H. (%)              44.1          41.7          39.6 - 43.9
Mean Vap Press. (mb)       9.76          10.50         9.81 - 10.89
Mean Max Wind (m/sec)      9.4            9.6           8.6 - 10.1
Mean Solar Rad. (kWh/m2)   5.94           5.85         5.50 - 6.20
Precip.(mm)               36.8           10.7           7.1 - 14.7
*Long-term refers to all of the Sevilleta met stations for 1989-2014

Albuquerque - Sevilleta Comparison

Albuquerque benefited much more than the Sev from the Sep 21-22 storm pushing it's monthly total past normal. There is now an even larger disparity of year to date precipitation between Albuquerque and the Sevilleta.

Three new daily high temperatures were set in Albuquerque on the 27th, 28th and 29th. This became the 4th warmest September in Albuquerque's 1893- present record. Only 2010, 1956 and 1998 were warmer. Of note 1983 had been the 4th warmest September. Considering the fact that 1983 and 1998 were at the end of very strong El Ninos, it might be a fair bet that Sept of 2016 could again be very warm.

               Loc         Precip          Normal         % of Normal
September      	ABQ        30.3 mm         27.4 mm           110 %
                SEV        10.7 mm         36.8 mm            29 %

Year to Date    ABQ       233.3 mm        186.9 mm           125 %
                SEV       162.9 mm        194.3 mm            84 %
Remember to check National Weather Service Monthly highlights at:

Water-year Precipitation

Happy New Water Year. A second dry monsoon month in a row doomed the chances of having an above normal water year for 2015. This makes 5 below normal water years in a row starting in 2011.

    Water Year Precipitation (mm)

Month           Mean            2013-2015    
Oct             23.0               6.4       
Nov             11.3               7.2
Dec		14.0		   9.7
Jan		 7.4		  20.8
Feb		 8.1		   4.8
Mar 		14.1		   6.3
Apr             11.9		  10.9
May		12.4		  36.0
Jun             14.8		  12.0
Jul		46.2		  49.1
Aug		42.2		  17.2
Sep		36.8		  10.7
               242.2             205.6


With only July precipitation coming in above average for the monsoon the total of 89 mm came in well outside 1 standard deviation of the September mean 142mm. Only 2003, 2011 and 2012 have been drier.

Of course this was not the case for much of the rest of the state. For example the monster July and the average September meant that despite a very dry August, Albuquerque got 135.6 mm as compared with its normal of 122.4 mm.


The NM drought situation appears to have held steady or improved during August. The Palmer Drought Index shows all of NM as in normal or in wetter than normal status

Despite the poor September the U.S. Drought Monitor reduced the area of the state with moderate drought down to only about 8%. The area of the state classified as abnormally dry (including the Sevilleta) has been reduced to 43%.

Regarding NM stored water, this page shows that it is a case of the glass being more than half full in some cases while in some cases, particularly the southern Rio Grande, the glass is mostly empty. Elephant Butte ended the year with 168.4 thousand acre-ft. This is 15% of its average (1,160 k acre-ft) and 7.6% of its capacity. This is about where it has ended the last 2 water years. However more water flowed down to the Butte this year and more was also released. This figure shows the comparison of this years Rio Grande average daily flow past Otowi to other years and to average.


A super El Nino appears to still be on track. The Sea Surface Temperature (SST) anomaly for the Nino 3.4 region started September at +2.2 degrees C and ended August at 2.4. The Oceanic Nino Index (ONI) for July-August-September rose to 1.5. This is the highest that it has been since 1997... when it was +1.7. Remember the 1997-98 El Nino is considered the high bar for El Ninos. The ONI maxed out at 2.3 at the end of Jan, 1998. The Southern Oscillation Index (SOI) continued in the El Nino direction in September as well, going from -1.4 to -1.6. This is the lowest that the SOI has been since 1998.

Go here to see the Albuquerque National Weather Service assessment of the effects of El Nino on October and November weather in northern and Central New Mexico.

Notables from on and off the Sev

Much of the vegetation on the refuge does not look so good.

Thousand year rain event out in the Carolina's began at the end of September. The rainfall amounts are being reported by feet rather than inches in some locations.

Some good news: almost all of the fires burning across the West and Northwest got brought under control by the end of the month. As of the end of Sep 9,085,000 acres had burned in the U.S - the 2005-2014 average is 6,252,440 acres. Only 46,181 acres burned in NM this year. This was only about 12 % of NM 2005-2014 average of 361,378 acres. I was surprised to see that last year's burn total of 23,491 acres was the lowest in the 2005-14 period. New Mexico's biggest year was 2011 1,255,000 acres


Major Hurricane Joaquin that spun up in late September seemed like it might become the hurricane story of the year and it still might but the initial predicted threats of landfall on the U.S. turned out to be completely wrong. Because of no threat to the U.S. few know that Hurricane Fred and 3 tropical storms Grace, Henri and Ida were all active during this September as well. Tropical Storm activity has turned out to be more active than predicted.

October Forecast

Let's start with September's forecast:

[NOAA is continuing to predict a cooler and definitely a wetter September. That would be more reassuring if they had not predicted the same thing for the previous two months.]

That being said NOAA's October forecast is just about the same - I guess they are going to be correct one of these months.


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