April 2018 Met Central - Typical La Nina April

April temperatures
returned to the generally warmer than normal
pattern that was the case through most of the winter. While there were
no daily high temperature records broken during April, there were only
6 days with average high temperatures that ran below the long term
average. Mean daily highs and mean daily lows and mean daily average
temperatures all ran well above normal. In fact this was the 4th
warmest April in the Sev LTER 29 year history. There actually was one
daily low temperature record set during the month.

    April Record Temperatures - High 34.0 (93.2 F), Low -10.2 (13.6 F)
    April '18 Record Temperatures - High 31.8 (89.2 F), Low -8.4 (16.9 F)

April precipitation on the Sevilleta just missed the goose-egg for the
month although 7 of the 10 Sevilleta met stations had no measurable
precipitation. This makes it the 3rd driest April in the SEV LTER
29-year history - both 1991 and 1996 had no precipitation during April.

April Meteorological Summary

                         April       April '18        April '18
Variable            Long-term* Mean    Mean           Mean Range
Mean Max Temp (C)         22.31            24.7         22.0 - 25.7
Mean Min Temp (C)          4.84             6.4          3.9 - 8.5
Mean Average Temp (C)     13.58            15.5         13.4 - 17.1
Mean R.H. (%)              28.4            19.3         18.6 - 22.5
Mean Vap Press. (mb)        4.00            3.43        3.29 - 3.56
Mean Max Wind (m/sec)      12.1            12.0         10.8 - 13.2
Mean Solar Rad. (kWh/m2)   7.21             7.70        7.10 - 8.24
Precip.(mm)                11.9             0.1          0.0 - 0.5
*Long-term refers to all of the Sevilleta met stations for 1989-2016

Albuquerque - Sevilleta Comparison

Albuquerque technically did even worse than the Sevilleta with only a
trace of rain on the 20th and 28th. Albuquerque has only gotten about
1/3 of its normal expected precipitation for this first third of the
year... not even an inch. At the same time the Sev has gotten almost
an inch which is almost 2/3 of its expected total.

This was the 8th warmest April in Albuquerque 123 year history.

               Loc         Precip          Normal         % of Normal
April		ABQ 	     T  mm         15.5 mm            0 %
                SEV         0.1 mm         11.9 mm            1 %

Year to Date    ABQ        18.4 mm         51.8 mm           35 %
                SEV        25.1 mm         40.2 mm           62 %
Remember to check National Weather Service Monthly highlights at:

Water-year Precipitation

The water-year total for the Sevilleta is now only running at 42% of normal.
Only one more month remains in the non-monsoon portion of the water year.

     Water Year Precipitation (mm)

Month           Mean            2017-2018    
Oct             22.5              12.2 
Nov             12.4               0.0
Dec		14.3		   0.0
Jan 		 8.9		   2.6
Feb		 7.5		  12.3
Mar		12.8		  10.1
Apr             11.9   		   0.1
                89.4		  37.2  


Understandably, drought conditions continued to worsen across New Mexico during

The U.S. Drought Monitor
rates 99.6% of NM is under some drought status
with 81% being under severe drought conditions, and 45% being under
extreme drought and now 11.6% under exceptional drought conditions.

The Palmer Drought Severity Index time series shows the continuing
progression into more and more severe drought.


The La Nina made a decided shift toward more neutral conditions during
April. The Sea Surface Temperature anomaly for the key 3.4 Nino zone
ended the month at 0.0, up from -0.7 at the end of March. The Ocean
Nino Index (ONI) for the Feb-Mar-Apr period was -0.6, up from -0.8
from the previous 3-month period. This makes six months in the the La
Nina range ( by the end of May.

The Southern Oscillation Index (SOI) continues to see-saw wildly going
from went +1.1 in January to -0.5 for February to +1.5 in March and
then to +0.5 in April. The 5-month running mean is +.50, exactly on
the boundary of La Nina and neutral.

Notables From On and Off the Sev

It was the 3 warmest April
globally on record. Only warmer were 2016 and 2017. Do we see a
trend here? And no, it is not global cooling.

May Forecast

NOAA predicts a much warmer than normal May but is giving equal
chances of above or below normal precipitation. .

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