A rather static weather pattern has held across South America since October.
A cold pool of Pacific Ocean water has persisted to the west of South America since September (La Nina). And warming ocean temps has developed to the east of Argentina (circled in red), which is creating a fast-moving jet stream and high pressure Ridging across E Argentina. It’s the fast jet and Ridging which is limiting precipitation.
And with La Nina in a strengthening phase again, we doubt that the current arid Argy weather pattern is going to break in the next 2-3 weeks. Unfortunately, the same weather pattern looks to persist into March.
Brazil has enjoyed near to only slightly below normal growing season rains which has favored crops. But the odds are being tilted in favor of drying across N Brazil during March and April as the onset of the winter comes early.
The time frame for soaking rainfall is immediate for Argentine crops. The forecast calls for rains of .25-1.25” across the northern half of Argentina this weekend, followed by warming and dry weather for much of next week. Heat returns beyond Tuesday with highs returning to the 90’s/100’s. A few lite showers are possible next weekend, before additional dry weather returns.
** No Change in US; Drought to Expand: The GFS model in recent days has hinted at possible rainfall in OK/KS, but totals will be mostly lite/scattered, and the overall pattern will remain dominated by La Nina into the end of winter. The latest US Drought Monitor is at left, and the year-over-year change is below. The issue ahead is the forecast for drought conditions on March 1, which were non-existent a year ago, but look to remain in place in 2018.
Mostly dry/cool weather lies ahead into Feb as the Polar Vortex is positioned a bit farther south than normal. Bitterly cold temps will persist across the N Plains and Great Lakes Region, and at times overnight lows will fall into the teens as far south as KS & MO. It’s possible that isolated showers do impact the Plains in the next two weeks, but it’s clear meaningful precip will maintain an eastward bias indefinitely. Rainfall in excess of 1” will be confined to the Delta/Southeast and far S Plains.