Domestic Weather:

• Strong high pressure sits over the Great Plains this morning, running from ND down to TX, and this is a dividing line between what’s happening in the eastern and western parts of the country.
• Lake effect snows are pounding areas in the Great Lakes region and isn’t associated with a system, it’s more wind-driven.
• As high pressure moves east through tomorrow, a strong low will take its place, working into the central plains overnight tomorrow night.
• Moisture will move in well in advance of the low, stretching from the northern plains through the Great Lakes and into the eastern Corn Belt through Sunday morning.
• The heaviest snows will start in southern MN and northern IA, then will move through southern WI and northern IL, and ending up in IN and OH.
• The low will lift northeast Sunday night-Monday of next week, dragging more moisture with it through the Corn Belt, and a lot of that moisture will be snowfall; from I-70 northward you’ll see snowfall and from I-70 southward, it’ll be rain fall.
• Totals from the weekend event will be 4-8” maximum, with the liquid equivalent will be .25-.75” of moisture.
• High pressure will move in behind it on Monday night-Tuesday, then with bitter cold arctic air coming in, we’ll see several clipper systems move through.
• When the cold air advances in on Tuesday, snows move through the Upper Midwest and Great Lakes and all the way down through IN.
• Snows likely will be a coating to 1” or so, and then dry weather moves in behind that little event.
• After the first clipper moves out, that’s when temps begin to ratchet down, with the zero-degree line coming all the way down to I-80 on Wednesday-Thursday.
• A strong system will come together later in the week as high pressure moves out.
• Low pressure moves out of the central Rockies into the central plains on Friday, putting down significant snows in NE, IA, IL, and IN.
• That low tracks eastward on Saturday, moving across the boot heel of MO before lifting northeast; it could set down significant snowfall totals in the eastern Corn Belt.
• Models are in wide disagreement on totals, but I think we could be looking at a classic winter storm in the Corn Belt, putting down anywhere between 4-10” of snow or better, depending on how things emerge.
• High pressure moves back in behind the event and that cold air just doesn’t go anywhere as we see another arctic blast as we kick off the week ahead of Christmas.
• Light snows move through the middle of the country on Dec 19-20, including KS, NE, MO, and IA, with totals of up to 3” with more cold air advancing.
• Overall, the pattern is very active and very cold across most of the country.
• There will be less of a stormy picture ahead for the Deep South, since the cold air pushes far enough south to make it through the Mason Dixon line.
• By the end of next week, the 32-degree high line will push down to settling in across MO, AL, and GA borders with TN, through central/southern AR.
• That cold air will cause a pullback in stormy weather that’s developed recently in the Deep South.
• There isn’t a lot of action in the western US, with the southwest likely trying to be above normal this week before going below normal the next week.
• There will be some nice snowfalls in the higher elevations, but there won’t be much going on in CA and the Pacific Northwest.
• The pattern would seem to suggest not a lot of moisture falling up in the Canadian Prairies, but there will be a whole lot of cold air, with temps falling below zero and staying there for the next couple of weeks.

South America weather:

• Watching a frontal boundary coming together down south as Paraguay picks up heavy rains today-tomorrow.
• This front looks to move northward slowly, moving through Matto Grosso do Sul through Sao Paulo with rain totals of 2-3” easily over the next 2-3 days combined.
• It takes its time moving north, so we’ll see scattered
  showers yet this weekend in Matto Grosso, Goias, and Minas Gerais, but the front does fall apart the further north it goes.
• Scattered showers in the central/north areas of Brazil will add up to 1-1.5” over the next 4-5 days, but still no significant frontal boundary will arrive with the moisture.
• By the second half ofnext week, an organized front will lift north from Wednesday night-Friday, putting down 1-3” across MG, Goias, southern Bahia, western Minas Gerais, with coverage at 80-90%.
• The second half of next week won’t see much moisture in the southern half of Brazil and that’ll continue into early next week; some areas in the south could actually be completely dry.
• Some of the drier areas could include Paraguay, southern MGDS, through Parana and Sao Paulo, and southward through Rio Grande do Sul.
• Still, the ten-day picture has nice moisture in Brazil and the 11-16-day forecast shows that pattern continuing.
• Temps will be normal/slightly above in the daylight hours, but the overnight periods continue to be cooler with temps below normal each night.
• This kind of setup will continue to favor crop development and we don’t see any major headaches or problem areas in Brazil at this point.
• The trade has been talking a lot about lack of moisture in Argentina; it will be mostly dry today-tomorrow, with a few scattered showers in northern Argentina.
• A few scattered showers come together late in the weekend/early next week, especially on Tuesday, with scattered showers falling over 30% of Argentina’s growing areas.
• High pressure moves in Wednesday-Thursday of next week, but more precipitation will follow at the end of next week.
• A batch of showers will develop over Buenos Aires province, northern La Pampa, and southern Cordoba on December 18-19, lifting across 60% of Argentina’s growing areas.
• It looks like Argentina isn’t in quite as good a shape as Brazil over the next ten days as they’ll only see scattered hit and miss showers covering roughly 40% of the region over the next 10 days.
• It won’t do anything to address the perceived dryness in southwestern parts of the country.
• At the same time, we continue to see temps below normal in Argentina and no significant heat is looking to move in.
• There is a warmer push of air in the south by the weekend, but this will go away quickly moving through next week as a good chunk of it will be back to below normal temps.
• The dryness isn’t the best-case scenario for Argentina crops, but it’s also not the worst-case scenario either.
• If the pattern changes between now-December 30, things will be in good shape; we’re not raising any red flags just yet.

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