News
03/20/2023, 9:28 pm EDT
Charts of the day: Last week’s rainfall across South America and the 7-day rainfall forecast. Discussion: Last week, dryness was immense across most of the Northern Argentina drought zone plus Southeast and Northeast Brazil. However, heavy rains were observed across Central Brazil to the North Coast and in West-central Argentina. Week-2 Valid March 27-April 3, 2023, 2022: Beneficial rain in core of Argentina drought zone. Discussion: The core of the Argentina drought area receives beneficial rainfall while Brazil trends drier next week. Early period brings heat to Argentina suppressed once the wet weather arrives. Week-3 Valid April 3-10, 2023: Wet pattern except Southeast Brazil. Discussion: Wet weather continues across Argentina heaviest in the central drought zone. Brazil turns wetter. Temperatures are suppressed due to the wet pattern. Week-4 Valid April 10-17, 2023: Drier weather returns to Argentina. Discussion: Drier pattern returns to Northern Argentina. East-central Brazil is a wet spot.
03/20/2023, 8:27 pm EDT
Charts of the day: Daily soil moisture analysis and 7-day rainfall forecast. Discussion: Drought concerns in Europe include France, Italy, and the Western Black Sea region. Short-term precipitation is abundant but mostly north of the dry zones. Note the wet soils across Western Russia although the shot-term forecast is dry and unusually warm. Week-2 Ahead Forecast valid March 27-April 3, 2023: Wet weather stretches across the Northern half of Europe and into Western Russia. Discussion: A Northwest to Central Europe upper trough inspires widespread wet weather from the U.K. for Central Europe and eastward during the period. Much of the rain is north of the France to Italy drought zone. Anomalous warmth dominates Northwest Africa to Spain and the Black Sea region eastward. Week-3 Ahead Forecast valid April 3-10, 2023: Showery/temperate Central Europe. Discussion: ECM projects an upper trough across Northwest Europe which creates a showery regime suppressing any warm risk. Warmth persists near and northeast of the Black Sea region although with less amplitude. Most of the Southern Europe and Black Sea region drought zones are missing the rain. Week-4 Ahead Forecast valid April 10-17, 2023: Black Sea (and eastward) drying is an evolving concern. Discussion: The upper-level ridge pattern broadens across the Black Sea region and northward sustaining a dry and warmer than normal pattern in that zone. Western Russia through Central Europe are marginally wet and temperate.
03/20/2023, 7:10 pm EDT
Charts of the day: GFS scoring best on medium-range temperature bias. Discussion: During the past 30 days the U.S. medium-range forecasts have been too cool in the East by the GFS while ECM ENS is too cool for most of the U.S. The GFS operational model cool bias (above) has the least error. The cool bias is generally attributed to over-emphasis of snow cover which of course has been lagging in the East this winter season. Week-2 Ahead Forecast valid March 27-April 3, 2023: ECM maintains West U.S. chill; other models agree. Discussion: -PNA pattern coupled with snow cover validates the ECM claim of widespread chill across the West and into the Great Plains. Coldest anomalies are across North Dakota and the Great Basin. The Southeast is not as cool as previously indicated and could be warmer than shown here. Heavy rain risk is indicated for the Tennessee Valley while California has remaining Pacific storms although with less intensity. Week-3 Ahead Forecast valid April 3-10, 2023: Nationally, cooler than normal. Gulf of Mexico storm track. Discussion: Blocking pattern supports the ECM claim that most of the U.S. is cooler than normal. The storm track shifts southward to the Gulf of Mexico with wet weather extending to the Gulf States. Week-4 Ahead Forecast valid April 10-17, 2023: Cool pattern easing; Texas rains. Discussion: The trend in Texas is wetter. Dryness stretches across the northern states. The chilly pattern eases but anomalous warmth is limited.
03/20/2023, 1:53 pm EDT
India wet threat, more so than models indicate. Some beneficial Argentina rains. Vivid Europe storm track. West drier/East wetter in U.S. medium-range. Fig. 1-2: The daily Indian Ocean SSTA analysis and 15-day total rainfall forecast for India. Discussion: Last week turned wetter across India although the northeast portion of the nation did not receive much rain and consequently dry soils in that zone are strengthening. However, there are wet climate parameters developing. In the northwestern Indian Ocean, the SSTA pattern has become very warm during the past 1-2 weeks (Fig. 1). The warmer than normal SSTA is well-correlated to increased low atmospheric moisture which enables wetter climate patterns. The latest 15-day rainfall forecast across India (Fig. 2) by the GFS indicates areas of heavy precipitation especially near mountain areas. The rainfall for the peninsula could be higher than indicated given the warm SSTA to the west and embedded short-wave energy in the prevailing westerlies aloft. In South America, the Argentina drought roars on. However, wet weather is in the forecast, especially central and southern areas this week (Fig. 3). In the 6-10-day-period the mega-cluster ensemble places rainfall risk across the core of the Argentina drought zone (Fig. 4) likely to persist in the extended-range (Fig. 5). Fig. 3-5: The 15-day precipitation anomaly forecast using the mega-cluster ensemble for South America. Fig. 6-8: The 15-day precipitation anomaly forecast using the mega-cluster ensemble for Europe A storm track stretches across Western Europe to the Baltic States this week (and next) based on the latest mega-cluster ensemble (Fig. 6-8). The drought zone in France to Northern Italy may miss most of the precipitation. Finally, this week should bring the last of the “atmospheric river” storm patch across California (Fig. 9). In the medium range the western half of the U.S. slowly turns drier while the wet weather risk shifts to the East States (Fig. 10-11). Fig. 9-11: The 15-day precipitation anomaly forecast using the mega-cluster ensemble for the U.S.