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August & Summer 2012  

  • Using the radar-derived estimated observed precipitation from the RFCs, rainfall totals for August 2012 ranged from around a meager 0.50” in isolated areas to near 8” in a few spots. Most of the HSA received 2”-4”. Localized rainfall this month meant that some areas of eastern OK and northwest AR received near to above normal rainfall for August, but many areas only received 25-75% of the normal August rainfall. Portions of central Osage County only received 10-25% of the normal August rain.
  • The remnants of Hurricane Isaac (which made landfall near the mouth of the Mississippi River in Louisiana at 645pm CDT on Aug. 29, 2012 with sustained winds of 80 mph) affected far eastern OK and northwest AR beginning the evening of the 30th and continuing for much of the 31st before moving north into the Midwest. The center of the low pressure moved northward across western AR, with the highest rainfall totals occurring along and east of the track. Rainfall totals across western AR ranged from near 0.25” to around 2” from Isaac, while little rain affected eastern OK. The exception was far northeast OK, where around 1” of rain fell, and across a few localized areas of east central OK.
  • Significant deterioration in drought conditions occurred during August 2012. According to the Drought Monitor from August 28, 2012, all of eastern OK and northwest AR were in drought conditions. Exceptional drought (D4) included portions of Osage, northern Pawnee, Ottawa, and northern Delaware Counties in northeast OK and Benton, eastern Washington, Carroll, Madison, and eastern Franklin Counties in northwest AR. Extreme drought (D3) was affecting the remainder of the HSA, with the exception of Pushmataha and Choctaw Counties in southeast OK, which were in Severe (D2) drought.
Summer (June-July-August) 2012
  • The Climate Prediction Center CPC outlook for September 2012 (issued August 31, 2012) indicates a slightly enhanced chance for above normal temperatures and an equal chance for above, near, and below median rainfall across eastern OK and northwest AR. This outlook was based primarily on short-term dynamic computer models and very low soil moisture effects.
  • For the 3-month period Sep-Oct-Nov 2012, CPC CPC is forecasting an enhanced chance for above average temperatures and equal chances for above, near, and below median precipitation across the region (outlook issued August 16, 2012). This outlook is based on dynamic computer model output, long term trends, and initial soil moisture conditions.
  • According to CPC, ENSO neutral conditions continued through August. Equatorial sea-surface temperatures continue to warm and there is an increasing chance El Niño conditions to develop during the Sep-Oct-Nov period.