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12/09/2018, 2:27 pm EST

U.S. Sunday Report

Highlight: Medium-range warmth could underachieve due to storms while extended-range will return U.S. cold. Day 1-5 Outlook (Dec. 9-13, 2018): Storms and cold. Historic snowfall in No. Carolina; near 30 in. parts of NC (Fig. 3). Lingering VA/NC snows Monday. Cold across snow cover into midweek East/Southeast. Waves of rain and snow into the Northwest U.S. As East storm departs and Northwest turns stormy, Central U.S. turns much warmer early week. Next storm organizing THU night Midwest; much warmer Southeast WED/THU ahead of that storm. Fig. 1-2: Climate Impact Company temperature and precipitation anomaly forecast for days 1-5 ahead. One of the strongest North Carolina snow storms on record. Large swath of 1-2 feet of snow southern Appalachians and eastward to central/southwest North Carolina. Widespread power outages and impassable roads. Snow is deep and delays any significant warm-up. Fig. 3: The GFS OP snowfall forecast beginning at 7PM SAT Dec. 8, 2018. Day 6 to 10 Outlook (Dec. 14-18, 2018): Northwest/East storms. Potentially, more stormy than indicated. Storm emerges East U.S.; snows in the mountains. Depending on intensity could be a coastal Northeast snowstorm. Storm generates local cold in northern Mid-Atlantic States. Also stormy in the Northwest; possibly colder than shown. Dry and warm Central States. Wet weather in southern Texas. Fig. 5-6: Climate Impact Company temperature and precipitation anomaly forecast for days 6-10 ahead. Day 11-15 Outlook (Dec. 19-23, 2018): New cold appearing. Be ready for a cold outbreak late in the period. Northern U.S. storm track could shift farther south late period. Warm/dry South (cooler late period). Fig. 7-8: Climate Impact Company temperature and precipitation anomaly forecast for days 11-15 ahead. Week 3 (Dec. 23-29) and week 4 (Dec. 30-Jan. 5) outlook: Broadening cold. Southern storm track generates local chill, snow cover and northward expansion with time. Wildcard: Any arctic air intrusions form the North. Fig. 9-10: Climate Impact Company week 3/week 4 ahead temperature anomaly forecasts for the U.S. Gas population weight 4-week HDD forecast: The outlook continues to indicate a national warm-up during mid-to-late December. However, the late DEC/early JAN forecast trends colder and could easily be much colder. The regional HDD departure forecast also indicates the warming for just-after mid-month. Later in December the West to ERCOT chills and that colder change reaches the Northeast in early January. Fig. 11-12: Climate Impact 4-week gas population weight HDD forecast.
12/05/2018, 3:33 pm EST

AG Market Roundup

Central/Northeast Brazil rains Australia wetter Queensland, dangerously hot/dry elsewhere South America: The dominant climate features across South America the first half of December are the cross-equatorial northeast fetch of moisture into northeast and central Brazil and persistence of an upper trough to the east of Brazil. The cross-equatorial wind flow is well-represented by a transition into the negative wind index of the Atlantic meridional mode. Meanwhile cool sea surface temperature anomalies reflect the persistence of the cool upper trough in that location in recent weeks. The combination of these two regimes is keeping central-to-northeast Brazil showery and wetter-than-normal. No major change in this pattern is expected over the next 15 days. Meanwhile to the south where high pressure is generally dominant a dry climate affects southeast Brazil to Argentina. The old pattern from earlier November forcing strong (and wet) cold fronts across Argentina is not completely finished. At least 2 and possibly 3 cold fronts transit Argentina over the next 15 days and only the 3rd which is forecast in 14-15 days carries significant rain. The long-term climate forecast for summer expected to shift wet weather into Argentina/southeast Brazil while northeast Argentina turns drier and caused by an evolving El Nino may be slow to occur. El Nino 2018-19 is struggling to develop in the atmosphere. So…other regional climate factors such as the –AMM regime emerge as lead catalysts for the early summer climate. Australia: Similar to South America, the Australian climate is being influenced only marginally by the El Nino southern oscillation (ENSO). Two factors govern the general climate over the next 15 days. A Rossby Wave is evident northeast of Australia both sides of the equator and represented by a large mass of thunderstorms. Meanwhile the Madden Julian oscillation (MJO) is forecast to re-emerge over the Indian Ocean and shift east to the north and northwest of Australia over the next 1-2 weeks. These events frame the weather forecast. Periods of wet weather will increase in Queensland this weekend and next week due to proximity to the tropical convection produced by the Rossby Wave. A more widespread shower risk is presented in 10+ days as influence of the MJO nears Australia to the northwest. Forecast models are convening most of the moisture over Queensland the next 2+ weeks. The wetter influences across north and northeast Australia expected to increase over the next 2 weeks are caused by convective currents which are compensated for by subsidence to the south from Western Australia to New South Wales. In this subsidence zone several extreme heat events occur the next 2+ weeks. The excessive heat accelerates drying for the southwest 2/3 of the continent and 1/3 southeast part of Australia. Regarding the long-term climate outlook…regional influences are likely to outweigh macroscale events. The MJO influence by mid-month is a good example while El Nino remains disorganized and the previous mature phase positive Indian Ocean Dipole fades. Europe: The pattern is dominated by two synoptic features: 1. Icelandic low pressure and 2. East/Southeast Europe low pressure. A steady stream of storms across the North Atlantic eject showery and windy conditions across Western Europe and northeastward across Scandanavia. Meanwhile upper level troughs over Turkey or Southeast Europe stagnate or drift northwestward to Eastern Europe. It’s the same old story as blocking high pressure over west-central to northwest portions of Russia either force North Atlantic storms across northern Europe or cause cutoff systems in Southeast Europe. Storms are fast-moving therefore amounts are not necessarily very intense. River levels begin to ease with at least some rainfall. Temperatures are cool Western Europe days 6-10 otherwise mild. United States: The Great Plains are dry and generally cold through the weekend. The next storm stays well south. Heavy snow will affect southwest and northern Oklahoma to northern Arkansas early this weekend with a sizeable ice storm in the southwest Great Plains. However, there is no blocking high pressure to the north of this storm (yet) therefore the storm is a relatively quick-mover. The storm may slow down off the East Coast when a blocking pattern emerges early next week. In the Great Plains precipitation events are minor and a steady warm-up is indicated. Forecast models are warm days 8-14/11-15 but record continental snow cover, stratospheric warming over Canada and the tendency for models to go too warm in the extended-range suggest that the big warm-up may be overdone.  
10/02/2018, 11:03 am EST

AG Roundup: Focus on Australia

Bureau of Meteorology/Australia locks-in +IOD forecast Coupled with expected El Nino, Australian (bad) drought expected Key will be extent of feedback dry soils have to amplify heat Chart of the Day: Where the Dry Soils Should Amplify Heat NOV/DEC/JAN 2018-19 According to IRI Discussion: A positive phase of the Indian Ocean dipole (+IOD) is now in effect. The +IOD regime is forecast by the Bureau of Meteorology/Australia to last into early 2019 (Fig. 1). A +IOD regime causes much of Australia to increase dry risk due to subsidence in the upper atmosphere and cooler than normal waters northwest of Australia which is typically a moisture source for Australian climate (Fig. 2). Cooler sea surface temperature anomalies (SSTA) reduce the amount of available moisture. Fig: 1: Bureau of Meteorology/Australia is now forecasting positive Indian Ocean Dipole into early 2019.   Fig: 2: The climate influence of +IOD on Australia is dryness for much of the continent. El Nino is also forecast by the Bureau of Meteorology/Australia heading into summer 2018-19 (Fig. 3) which should further enhance drought risk. A forecast of lack of rain is a major issue for Australia. The JUL/AUG/SEP 2018 rainfall anomalies were sharply drier than normal for much of the continent (Fig. 4). The new concern is the extent that drought will have on the atmosphere as a feedback mechanism to amplify anomalous heat. Fig: 3: Bureau of Meteorology/Australia continues to forecast El Nino for 2019 with onset in late 2018. Fig: 4: The JUL/AUG/SEP 2018 precipitation anomalies across Australia.