Following The Current And Future Temperature Extremes
07/28/2021, 5:51 am EDTUpdated August 2021 North Atlantic Tropical Cyclone Season Outlook
08/01/2021, 6:53 pm EDTHighlight: Agriculture Powerhouse Brazil Slammed With Historic Snow, Ice and Freeze!
Fig. 1: Yesterday was the coldest day of the outbreak but Friday morning lows are still in the -1C to -5C range in Southeast Brazil.
Discussion: For many folks in Southeast Brazil a first-time experience witnessing snow and ice occurred on Thursday as a historic cold outbreak surged northward across all of the South/southeast Brazil crop areas. Corn, coffee and orange crops were harshly affected according to various news agencies and Brazilian meteorological services. Widespread historic cold, icy roads and snow in the air on Thursday morning. The cold is not quite as harsh but remains in-place this morning across Southeast Brazil (Fig. 1).
The culprit was a negative spike in the Antarctic oscillation (AAO) at -2.0 during midweek. The -AAO was brought on by a high-latitude high-pressure ridge across Antarctica to southeast of New Zealand which ignited 5 very intense longwave trough(s) each causing unusual cold when engaging continents. The most intense upper trough crossed South America early yesterday causing the historic icy chill which caused widespread agriculture damage.
Fig. 2: Antarctic oscillation spiked at -2.0 yesterday and was associated with 5 potent longwave trough(s) in the southern hemisphere two of which delivered cold weather to Australia and Brazil.