Northern Hemisphere: Weather & Climate over Major Crop Areas Update prepared by Climate Prediction Center / NCEP 2 August 2010 For Real-time information:

Outline Highlights ENSO Current Status MJO Current Status Monsoons Current Status Northern Hemisphere Circulation Rainfall & Temperature Patterns NCEP/GFS Model Forecast Forecast Verification

Canada and US: The past week brought a return to seasonally average temperatures for the Northeast and the Great Lakes, but above-average temperatures continued across the southeast. Showers and thunderstorms associated with the North American monsoon continued to affect Arizona and New Mexico, and periods of convection continued in the Plains. The GFS forecasts a continued wet pattern for the Plains, with below-average precipitation for the southeast. Mexico and Central America: Heavy rain fell in northwest Mexico and across Central America during the past week, and heavy rainfall is forecast to continue in Central America during the upcoming week. Eurasia: Hot and dry conditions continued for western Russia, while heavy rains in Pakistan triggered flooding. The GFS forecasts above-average precipitation for Indonesia, most of south Asia and for the Gulf of Guinea region of central Africa. Highlights

ENSO Current Status For more information go to: During the last 4 weeks (4 Jul – 31 Jul 2010), SSTs were at least 0.5 deg C below average between 170 W and the South American coast. General Summary: La Niña conditions are developing across the central Pacific. Negative sea surface temperature anomalies continue to strengthen across much of the Pacific Ocean. The onset of La Niña conditions is likely during June-August 2010.

MJO Current Status  The axes (RMM1 and RMM2) represent daily values of the principal components from the two leading modes  The triangular areas indicate the location of the enhanced phase of the MJO  Counter-clockwise motion is indicative of eastward propagation. Large dot most recent observation.  Distance from the origin is proportional to MJO strength  Line colors distinguish different months MJO Index -- Recent EvolutionEnsemble GFS (GEFS) MJO Forecast RMM1 and RMM2 values for the most recent 40 days and forecasts from the ensemble Global Forecast System (GEFS) for the next 15 days light gray shading: 90% of forecasts dark gray shading: 50% of forecasts Yellow Lines – 20 Individual Members Green Line – Ensemble Mean For more information go to: The MJO index is currently centered over the western Maritime Continent and has shown a weakening trend in recent days. The GFS forecast shows continued weakening of the MJO signal into the Maritime Continent through the Week-1 period.

Northern Hemisphere Monsoons Current Status North AmericaWest AfricaEast Asia For more information go to: Rainfall Anomalies: Last 90 Days Monsoonal precipitation has begun to increase over the past couple of weeks across the Southwest. During the last 90 days near average rainfall has occurred in west Africa near Senegal and Guinea. Near to below average rainfall has occurred in the coastal Gulf of Guinea region and Sudan. During the last 90 days below average rainfall has occurred in southeast Asia and above average precipitation has occurred in eastern China. Monsoon Season: JUN-SEPMonsoon Season: MAY-OCTMonsoon Season: JUN-SEP

Northern Hemisphere Circulation 200-hPa, 925-hPa Wind & Temperature Anomalies - Recent 7 days During the 7-day period (24 Jul – 30 Jul 2010), anomalous 200-hPa anticyclonic circulation centers were located near Hawaii, the southeast US and in northern China. An anomalous 200-hPa cyclonic circulation center was located over central Asia. Above average temperatures were observed over eastern North America and western Russia. Low-level (~600 m) wind and temperature anomalies are based on the NCEP Climate Data Assimilation Systems (CDAS) analysis. The patterns of anomalous temperature and wind at 925-hPa are usually similar to surface observations. Note: Areas with surface pressure below 925-hPa are masked out. A A C A

Northern Hemisphere Circulation Rising motion (negative omega, yellow/red shading), usually associated with wetter- than- normal conditions. Sinking motion (positive omega, blue shading), usually associated with drier-than-normal conditions. Omega Anomalies and Total Precipitation - Recent 7 days During the 7-day period (24 Jul – 30 Jul 2010), anomalous rising motion (negative omega) was observed over the central US, eastern Europe, western India central Africa, and eastern Asia (top panel red ovals). During the same time period precipitation was observed over the same areas. CPC daily gridded precipitation analysis over land only. The daily gauge analysis is created on a 0.5 degree lat/lon over the global land by interpolating gauge observations from ~30,000 stations.

Canada and US Rainfall Total & Anomaly Patterns Temperature Patterns GFS Forecast

Rainfall Total & Anomaly Patterns: Last 7 Days TotalAnomaly During the last 7 days, showers and thunderstorms continued across the northern Plains; thunderstorms associated with the monsoon also continued across the southwest US. Heavy rainfall also affected parts of southwest Alaska. Much of the Northeast US and southeast Canada was drier than average.

Rainfall Total & Anomaly Patterns: Last 15 Days TotalAnomaly

Rainfall Total & Anomaly Patterns: Last 30 Days TotalAnomaly During the past 30 days heavy rain and thunderstorms have contributed to river flooding across parts of the central US, and enhanced rainfall has been observed over southern Texas from Hurricane Alex and T.D. #2 in July. Below average precipitation has been observed in the southeast, mid-Atlantic, Pacific Northwest and into western Canada.

Recent Evolution: Rainfall Last 30 Days

Temperature (°C) Based on GTS Stations (no QC) AnomalyExtreme Maximum During the past 7 days temperatures were above average in the Canadian Prairies and near to below average in southeast Canada. Maximum temperatures reached 25 to 30C in the Prairies and in southeast Canada. AnomalyExtreme Maximum

Temperature (°C) Based on GTS Stations (no QC) AnomalyExtreme Minimum During the past 7 days, several states in the Northeast and mid-Atlantic experienced a return to more seasonal temperatures, while above- average temperatures continued across the southeast and Intermountain West. In Mexico, below-average temperatures were observed in northern and central. High temperatures reached over 35C in northern Mexico. AnomalyExtreme Minimum

TotalAnomaly NCEP/GFS Precipitation Forecasts Forecasts from 02 Aug 2010 – Days 1-7 For Days 1-7 above-average rains are expected to continue for parts of the Corn Belt with a favored track for convective activity in this region. Below-average rainfall is forecast across most of the southeast and southern Plains. The GFS also forecasts some weakening of the monsoon later in the upcoming week. Near average precipitation is forecast for Canada.

NCEP/GFS Precipitation Forecasts TotalAnomaly For Days 8-14 the GFS forecasts continued wet weather for the central US, with near to below- average rainfall expected for the mid-Atlantic. Precipitation is expected to be near-normal across Canada. Forecasts from 02 Aug 2010 – Week 2

Forecast Verification: North America Total Anomaly Forecast from 19 Jul 2010 Valid 26 Jul - 1 Aug 2010 Forecast from 19 Jul 2010 Valid 26 Jul – 1 Aug 2010 Observed 26 Jul – 1 Aug 2010 Anomaly Total

Mexico and Central America Rainfall Total & Anomaly Patterns Temperature Patterns GFS Forecast

Rainfall Total & Anomaly Patterns: Last 7 Days TotalAnomaly For more information see: During the past 7 days, heavy rains contributed to above-average precipitation across Central America, while monsoon thunderstorms brought above-average precipitation to northwest Mexico.

Rainfall Total & Anomaly Patterns: Last 15 Days TotalAnomaly

Rainfall Total & Anomaly Patterns: Last 30 Days TotalAnomaly During the past 30 days, heavy rainfall associated with Hurricane Alex and TD #2 has led to well above-average rains in northeast Mexico. Enhanced convective activity has led to above- average rainfall in parts of central America, Cuba and Hispaniola.

Recent Evolution: Rainfall Last 30 Days

NCEP/GFS Precipitation Forecasts TotalAnomaly Forecasts from 02 Aug 2010 – Days 1-7 For Days 1-7 the GFS forecasts below-average monsoon rainfall in northwest Mexico, while above-average rainfall is expected across most of Central America.

NCEP/GFS Precipitation Forecasts TotalAnomaly Forecasts from 02 Aug 2010– Week 2 For Days 8-14 the GFS forecasts above-average rainfall across much of Mexico and Central America.

Forecast Verification: Central America Total Anomaly Forecast from 19 Jul 2010 Valid 26 Jul – 1 Aug 2010 Forecast from 26 Jul 2010 Valid 26 Jul – 1 Aug 2010 Observed 26 Jul – 1 Aug 2010 Anomaly Total

Eurasia Rainfall Total & Anomaly Patterns Temperature Patterns GFS Forecast

Rainfall Total & Anomaly Patterns: Last 7 Days TotalAnomaly During the past 7 days, very heavy rain triggered flooding over northwest Pakistan and parts of Afghanistan. Above-average rainfall also fell along the coast of western India, parts of southeast Asia, and eastern parts of Europe. Below-average rainfall was observed across much of China and western Russia.

Rainfall Total & Anomaly Patterns: Last 15 Days TotalAnomaly

Rainfall Total & Anomaly Patterns: Last 30 Days TotalAnomaly During the past 30 days above-average precipitation has been observed over southeastern Europe, eastern China, south Asia and Indonesia. Below-average precipitation has been observed over western Russia and northern China.

Recent Evolution: Rainfall Last 30 Days

Temperature (°C) Based on GTS Stations (no QC) AnomalyExtreme Maximum AnomalyExtreme Maximum Below-average temperatures were observed in most of central Europe, where maximum temperatures reached the 20s. In Northwest Africa, near to below-average temperatures prevailed across Tunisia and Algeria; above-average temperatures continued in Morocco.

Temperature (C) Based on GTS Stations (no QC) Anomaly Extreme Maximum Well above-average temperatures and mostly dry conditions continued in western Russia this week with highs in the mid to upper 30s. The hot and dry conditions have contributed to protracted drought in western Russia. In the Newlands temperatures were below average in Siberia and in Kazakhstan, but were above average in the Urals District.

Recent Evolution: Rainfall Last 30 Days

Temperature (C) Based on GTS Stations (no QC) Anomaly Extreme Maximum Near average temperatures were observed over India. Temperatures were above- average in China, where high temperatures reached 40C in a few locations in northern China.

NCEP/GFS Precipitation Forecasts TotalAnomaly Forecasts from 02 Aug 2010 – Days 1-7 For more information on Global Tropical Hazards see: (updated Monday at 4pm) For Days 1-7 below average rainfall is expected to continue in western Russia. A return to seasonably average rainfall is expected for eastern Europe. MJO activity supports wet conditions across Indonesia and southeastern Asia. Enhanced rainfall is also expected for the Gulf of Guinea region in western Africa.

NCEP/GFS Precipitation Forecasts TotalAnomaly For Days 8-14 above-average precipitation is expected across Indonesia and in parts of India and Pakistan. Below-average precipitation is forecast across eastern India and southern China. Forecasts from 02 Aug 2010 – Week 2

Forecast Verification: Eurasia Total Anomaly Forecast from 19 Jul 2010 Valid 26 Jul – 1 Aug 2010 Forecast from 26 Jul 2010 Valid 26 Jul – 1 Aug 2010 Observed 26 Jul – 1 Aug 2010 Anomaly Total

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