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Arctic blast up north, moisture gains down south

Temperatures across the northern tier of the country are bitterly cold once again as another Arctic front has plunged south from Canada. This front is currently progressing south and east through the southern Ohio Valley, with temperatures north of this front in the central and northern Midwest ranging from the teens above zero to single numbers below zero.

Northern Minnesota is seeing the brunt of the Arctic chill with morning temperatures ranging from -10 to -25. Across the HRW wheat belt, temperatures have fallen dangerously close to zero in extreme northern Kansas and southern Nebraska. I do not expect temperatures to fall more than an additional 2-3 degrees, although some very minor winterkill is possible in this area thanks to a lack of snowcover and temperatures near zero.

Temperatures across the SRW wheat areas are signficantly warmer, negating any winterkill threat this morning. The next chance for winterkill arrives Thursday morning. Once again, north/central Kansas into south/central Nebraska may see temperatures dip near to slightly below freezing. With no snowpack in place, it is quite possible some winterkill damage will occur, although coverage is not expected to exceed much more than 5-10%.

Farther east, there will be a greater threat for SRW wheat damage this go around, with areas most at risk for winterkill likely to be southern Illinois where a very thin/absent snowpack, in combination with temperatures near zero, could result in some patchy winterkill. Across Indiana and Ohio a snowpack should be in place, which will limit any winterkill threat.

The next major story, which is currently sending soybean futures plummeting, is the weather in Argentina. A quick look at the infrared satellite image across Argentina indicates a line of thunderstorms across northern Buenos Aires, southern Santa Fe, and southern Entre Rios. Rainfall totals over the last 24 hours indicate relatively widespread coverage of 0.5"+ from southern Cordoba and eastern La Pampa east into much of Buenos Aires.

The heaviest rainfal amounts (1-2"), fell across eastern Buenos Aires. After a round of morning thunderstorms across much of the central and eastern soybelt, more rainfall is in store for Argentine soybeans and corn Wednesday-Friday, with widespread coverage of 1-2" likely to fall from eastern Cordoba/La Pampa east to coastal portions of Buenos Aires. This rainfall, along with the arrival of cooler temperatures, should replenish to at least some extent soil mositure reserves and provide short-term relief to stressed crops.

A quick look at the Vegetation Health Index (VHI) across Argentina indicates values in the 0-24 range across SW Buenos Aires, La Pampa, and SW Cordoba (below 40 indicates stressed crops, 60 and above favors healthy crops). Even with rainfall over the next few days, at least some permanent crop damage/yield reductions will have likely resulted from recent extreme heat/dryness in these areas.

Across Brazil, the VHI is in the 40-80 range, with the highest values across the corn and soybelts of western Rio Grande do Sul and Parana. The overall long-term weather picture continues to look favorable for most of Brazil.

Freese-Notis Weather/Weather Trades, Inc. Des Moines, Iowa Copyright 2012 - All Rights Reserved

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