09/18/2023, 8:48 am EDT

North Atlantic Basin Week 2-5 Outlook

Headline: Keeping the Gulf of Mexico clean. Chart of the day: Morning satellite view of the North Atlantic. Discussion: Nigel will become a major hurricane within 1-2 days moving northwestward in the central North Atlantic subtropics. Nigel turns north and northeast accelerating toward Europe next weekend. ALERT for tropical cyclone development is issued for FRI/SAT off the Southeast U.S. Coast and east-central North Atlantic tropics. Week-2 Valid September 26-October 2, 2023: Subtropical rains Northeast Corridor Coast. Discussion: Subtropical rains affect the Northeast Corridor Coast. An actual tropical cyclone is in-doubt due to the recent cooling of the water surface. However, a tropical cyclone forming in the central tropics is likely to turn northwest, north, and northeastward staying out to sea. Week 3 Valid October 3-9, 2023: Another tropical cyclone near Bermuda. Discussion: A tropical cyclone strengthens north of Hispaniola and turns north toward New England or takes a hard right turn out to sea. Week 4 Valid October 10-16, 2023: Two systems possible. Discussion: Tropical cyclone risk continues into mid-October although the Gulf of Mexico is absent of risk. Week 5 Valid October 17-23, 2023: Minor late season risks emerge in the Gulf of Mexico. Discussion: The outer North Atlantic is likely to produce a late season tropical cyclone while minor risks emerge in the Gulf of Mexico.  
09/18/2023, 7:52 am EDT

U.S. Selected Cities HDD Forecast for 2023-24

09/17/2023, 1:17 pm EDT

U.S. Energy Market Sunday Report: Mississippi River continues to run below “low stage”. Western North Atlantic tropics continue to look quiet.

Fig. 1-3: The 12Z GFS medium-range U.S. temperature anomaly forecast and 15-day rainfall anomaly outlook. Discussion: At midday, the 12Z GFS continues to promote somewhat warmer than normal medium-range forecasts for the Central U.S. and gradually the Eastern States (Fig. 1-2). The trend in the East for the medium-range is less warm while the West-central U.S. may stay warmer longer. The rainfall forecast is trending drier since late last week (Fig. 3). Below “low level” on the Mississippi River will be steady or worsen as wet weather risk has lowered into early October. The western North Atlantic basin looks quiet into early October. Lee is inland and weakened while Margot erodes from upper shear. Nigel is forecast to stay out to sea this week (Fig. 4). The U.S. population weight CDD forecast is slightly cooler this week end next and slightly warmer for Sep. 29-Oct. 5 (Fig. 5). Fig. 4-5: ECM ensemble potential forecast tracks for Nigel and U.S. population weight CDD forecast by all operational models, their consensus and comparing 24 hours ago and the 10-year/30-year normal.            
09/17/2023, 11:00 am EDT

Daily Feature: Correlating Northeast Pacific SSTA and Europe Winter Temperature

Highlight: October Northeast Pacific SSTA & Following Winter Europe Temperature; Warm Northeast Pacific implies Mild Europe Winter Northeast Pacific Europe Winter Climate 1994-95 Warm Warm 1995-96 Cold Cold 1996-97 Cold Cold 1997-98 Warm Warm 1998-99 Cold Cold 1999-00 2000-01 Warm Warm 2001-02 2002-03 2003-04 2004-05 Warm Warm 2005-06 2006-07 Warm Warm 2007-08 2008-09 Cold Cold 2009-10 Cold Cold 2010-11 Cold Cold 2011-12 2012-13 Cold Cold 2013-14 2014-15 Warm Warm 2015-16 Warm Warm 2016-17 Warm Warm 2017-18 Warm Warm 2018-19 Warm Warm 2019-20 Warm Warm 2020-21 Warm Warm 2021-22 2022-23 Warm Warm Table 1: During the past 30 years, there is a tendency for correlation between Northeast Pacific SSTA patterns in October and the following wintertime upper air pattern that produce the Europe thermal regime. Fig. 1-4: Temperature anomalies for cold (warm) winter seasons during the past 30 years in Europe and the attendant North America/Europe upper air pattern. Discussion: When was the last cold winter season in Europe? Sprawling meteorological winter (DEC/JAN/FEB) cold was last observed during winter 2012-13. Since that time, 8 of 10 winter seasons have been warmer than normal across Europe (Table 1). During the past 30 years, 7 widespread cold winter seasons have been observed clustering in the mid-to-late 1990’s and in the 2008-2013 period. The cold winter seasons have produced widespread anomalous chill centered on the Baltic States and extending southward to France, Northern Italy, and Ukraine (Fig. 1). The attendant upper air pattern (Fig. 2) has featured a bold cold trough over Europe associated with a Greenland high-pressure blocking pattern known as negative North Atlantic oscillation (-NAO). Farther upstream, the -NAO pattern stretches an upper trough from Western Canada to the East U.S. In the Gulf of Alaska, the SSTA pattern is colder than normal in each of these cold winter years for Europe. During warm winter seasons, most of which (from the past 30 years) have occurred within the past 10 years, the anomalous warmth is profound and centered on Poland to Romania and Ukraine (Fig. 3). Warm winter in Europe is well-correlated with warm SSTA patterns in the Northeast Pacific in which the prevailing upper air pattern flips to high-pressure ridging from Alaska to the Northeast U.S. to Southeast Europe (Fig. 4). A cold trough emerges over Scandinavia and the high- pressure block over Greenland is gone. The tendency for warm Northeast Pacific SSTA during the past 10 years began with emergence of the Northeast Pacific “warm blob” in late 2013. The “warm blob” became known as a persistent marine heatwave (MHW) prevailing in this region for much of the past decade. The current MHW, given a number by NOAA (NEP23A), suggests the Northeast Pacific is likely warm again for upcoming winter implying above normal anomalous warm climate risk for winter 2023-24 in Europe. Fig. 5: The Northeast Pacific SSTA pattern identifies the presence of another ongoing marine heatwave (NEP23A).