The North American Monsoon System: Recent Evolution and

Current Status

Update prepared byClimate Prediction Center / NCEP

08 August 2011

Outline

• Recent Evolution and Current Conditions

• Summary

• Climatology

Rainfall Patterns: Last 7 Days

During the past week, near-normal rainfall has been observed over southwestern US while the west coast of Mexico experienced drier-than-average conditions.

Rainfall Patterns: Last 30 Days

Near-normal rainfall has been observed over southwestern US during the past 30 days.

Recent Evolution: Rainfall

NCEP/GFS Week 1&2 Forecast

Near-normal precipitations for Southwestern U.S. during the Aug. 08- 21, 2011 period.

Summary

• During the past week, near-normal rainfall has been observed over southwestern US while the west coast of Mexico experienced drier-than-average conditions.

• NCEP GFS week 1 and 2 bias-corrected forecasts show near-normal rainfall over southwestern US during the Aug. 08 - 21, 2011 period.

The NAME Forecast Forum 2011 web page is up. For details, please visit:

http://www.cpc.ncep.noaa.gov/products/Global_Monsoons/American_Monsoons/NAME/index.shtml

ClimatologyMONSOON ONSET

June 5

June 6June 6

June 8June 7

June 14June 14

June 17June 16

June 23

June 27June 25June 29

July 3July 6July 11

July 7July 8July 13

July 9July 13July 14

June 10June 11

June 22June 21

Higgins, R. W., Y. Chen and A. V. Douglas, 1999: Interannual Variability of the North American Warm Season Precipitation Regime. J. Clim, 17, 653-680

Precipitation ClimatologyPrecipitation Climatology