11/30/2022, 5:50 am EST

U.S. Month 1-3 Ahead Outlook: Colder short-term forecasts into the East force a December update.

Executive Summary: The Climate Impact Company month 1-3 ahead climate outlooks for the U.S. valid for meteorological winter are updated. The forecast is updated due to colder East U.S. short-term forecasts. Later December is likely warmer in the East. However, short-term cold forces a monthly average closer to normal rather than warmer than normal as previously indicated. The January outlook is revised warmer for the southern half of the U.S. while February remains cold to very cold across the northern half of the nation. Methodology: The December outlook is an adjustment between consensus and operational models. The mid-to-late winter forecast remains based on La Nina climatology, optimum climate normal and consensus of NCEP CFS V2 and ECMWF operational climate forecasts.   Climate discussion: Snow cover becomes a leading catalyst to guide temperature forecasts as meteorological winter arrives. Snow cover is above normal across the northwest quadrant of the U.S. supporting a colder look which was expansive across the entire western half of the nation in November. The northeast quadrant of the U.S. generally lacked snow (except the eastern Great Lakes region) during late autumn biasing the November regime warmer than normal. Snow cover is expected to increase Great Lakes and Interior Northeast in early December supporting a colder regime ahead. Ocean waters have cooled significantly off the West Coast of North America and east-southeast of the Canadian Maritimes. The cooling waters have resulted in persistent strong upper trough patterns across or down wind of those cooling zones which should persist this winter season coupled with a still strong La Nina climate pattern. U.S. drought: Drought remains expansive across the U.S. with drought intensity likely to continue across much of the Great Plains with expansion in the Gulf States biased toward the Southeast U.S. Mississippi River water level: Water level recovery has occurred during late November for the southern basin. However, reliable precipitation to end the low water issue is not forecast for the winter season. U.S. gas population weight HDD forecast: The outlook is updated and indicates colder than 10-year normal monthly solutions through February. Winter 2022-23 is cold North and warm South and on average colder than recent winter seasons. Fig. 1: The Climate Impact Company U.S. population weight HDD forecast compared to the last 3 winter seasons and the 10-year climatology. December 2022: Northwest U.S. chill extends eastward following new snow cover from the Great Lakes eastward. A Greenland high-pressure block forces a cold trough on the East Coast early-to-middle December. No arctic air is involved but moderately cold weather is likely and made colder if snow cover is generated by the upper trough. The trough departs just after mid-month and the East turns warmer. The Northwest to North-central is colder than normal with occasional periods of frigid arctic air with sustained snow cover. The Southern States are generally warmer and drier than normal. The East Coast is adjusted stormy with interior snows likely to help enhance locally cold weather the first half of the month. Fig. 2-3: The Climate Impact Company temperature/precipitation anomaly forecast for December 2022.  January 2023: The updated mid-winter forecast indicates broad warmer changes south of prevailing snow cover. The northern states remain cold. The prevailing storm track is in-between the opposing thermal regimes. The Ohio Valley is snowier and cold be colder than indicated. The Northwest is also snowy. The southern tier of the U.S. is quite dry. Fig. 4-5: The Climate Impact Company temperature/precipitation anomaly forecast for January 2023.  February 2023: The final month of meteorological winter maintains a cold to very cold pattern across Canada extending to the Central U.S. and possibly the Northeast States. Expect a snowy month Interior East/Northeast U.S. The West Coast storm track is also quite potent while the southern states remain dry. Fig. 6-7: The Climate Impact Company temperature/precipitation anomaly forecast for February 2023.         
11/21/2022, 4:54 am EST

Europe Month 1-3 Outlook: Marginally mild forecast for winter in Europe. However, the forecast trend is colder especially if snowy.

Executive Summary: There are a lot of red flags for the Europe winter 2022-23 forecast. Pieces of the persistent NAWH upper trough are ejected eastward across Europe frequently during December and January. Each month is stormy for Southeast/East Europe (and Ukraine). The concern is the upper trough could generate a deep snow cover and bias the forecast colder than indicated. By February, widespread snow cover is present and could bias an already chilly forecast colder. The CIC-CA forecast indicates marginally mild temperatures (due to the warm SSTA surrounding Europe during winter) for Southeast Europe and is normally cold elsewhere. The forecast trend is colder and stormy. If the precipitation is mostly snow, a colder result is likely. Fig. 1-2: The Climate Impact Company temperature and precipitation anomaly forecast for DEC/JAN/FEB 2022-23 across Europe. Climate: As the last third of November arrives, there are significant winter signals appearing across Eurasia. Most important is the expansive snow cover well ahead of schedule across Asia and recently evolving over Eastern Europe (Fig. 3). The North Atlantic warm hole (NAWH) is vividly depicted in North Atlantic SSTA analysis although waters surrounding Europe remain warmer than normal (Fig. 4). The combination of expanding snow cover to the east of Europe and the NAWH upper trough implies the climate pattern heading into meteorological winter will produce a conflict between warm influence from the west and cold weather risk from the east. The ECMWF global SSTA forecast for mid-winter yields a warm North Atlantic including waters surrounding Europe with the NAWH well-established south of Greenland. La Nina is not quite as strong across the eastern equatorial Pacific Ocean (Fig. 5). The SSTA forecast yields support to above normal 500 MB heights across Europe for the winter season which correlates to a mild climate. However, arctic air is low-level in character and can emerge despite above normal 500 MB heights. Fig. 3-5: Northern hemisphere snow cover, North Atlantic warm hole, and global SSTA forecast by ECMWF for January 2023. December 2022: A piece of the NAWH semi-permanent trough shifts eastward to Europe on a regular basis during early meteorological winter. Consequently, the forecast is confident producing a stormy pattern across South and Southeast Europe and most likely Ukraine. Only Southwest Europe is drier than normal during December. The temperature forecast is not as confident. There is gathering arctic air over Central Asia during late November. The CIC-CA forecast has difficulty knowing how far west that air mass could travel. If the cold pattern to the east extends westward, most of the precipitation in Southeast Europe is snow and invites a much colder solution. Additionally, the upper trough parks over Central Europe, which could also trigger a colder forecast is snow cover is present. The CIC-CA forecast emphasizes a warm bias due to the much warmer than normal surrounding waters around Europe. The forecast is certainly trending less warm and the stormy weather shifts from Western Europe in the previous outlook to Southeast Europe. Bottom line? Trending more stormy, less mild and could be colder. Fig. 6-7: The preliminary Climate Impact Company temperature and precipitation anomaly forecast for December 2022 across Europe.  January 2023: The CIC-CA forecast is marginally mild across Eastern Europe through Ukraine and normally cold elsewhere. There is not much change from the previous forecast. Once again, part of the NAWH upper trough is emitted eastward and becomes semi-permanent over Eastern Europe. The upper trough should produce a large swath of above normal snowfall across Central and East Europe to the Black Sea region. Once again, the CIC-CA forecast is warm-biased due to warm SSTA surrounding Europe especially across the Mediterranean Sea. The forecast could easily be colder and would certainly not be warmer. Fig. 8-9: The Climate Impact Company temperature and precipitation anomaly forecast for January 2023 across Europe. February 2023: Similar to the U.S. winter forecast, February is the coldest month (relative to normal) across Europe. The colder look is produced by above normal snow cover. The forecast trend is colder. The upper air pattern supports a less stormy month except in Southeast Europe where heavy snow could occur. Once again, due to widespread snow cover, the outlook could be colder than indicated. Fig. 10-11: The Climate Impact Company temperature and precipitation anomaly forecast for February 2023 across Europe.