U.S. Winter 2022-23 Climate Outlook

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    Highlight: Sharp month-to-month climate variation during winter 2022-23 average warm in the Southwest and East/Cold North-central.

    Executive summary: The Climate Impact Company winter 2022-23 outlook indicates a warmer than normal climate pattern across the Southwest U.S. including California and the East/Southeast U.S. States. The cold weather risk zone is the North-central U.S. There is significant month-to-month variability including a January thaw most evident in the Central U.S. followed by a “polar vortex” chill in February also focused on the Great Plains. Winter 2022-23 is dry on the West Coast and immediate Gulf Coast with wet weather risk extending from Arkansas to Kentucky. Significant month-to-month fluctuations in Northern U.S. snow cover is expected.

    Fig. 1-2: The Climate Impact Company constructed analog winter 2022-23 temperature and precipitation anomaly outlook.

    Winter 2021-22 forecast and verification: The Climate Impact Company winter 2021-22 meteorological winter outlook featured a cold pattern for the Central U.S. with warmth across the Southwest States while California was very dry and the far Northwest U.S. and Arkansas were wetter than normal. The verification was excellent for Northern U.S. chill but the southern extent of the cold forecast was overdone and the Southeast observed a very warm winter. The precipitation forecast was not wet enough in the Mid-south U.S. and not dry enough on the Gulf Coast. The dry California forecast was correct.

    Fig. 3-6: The Climate Impact Company constructed analog winter 2021-22 temperature and precipitation anomaly outlook

    Climate discussion: A list of prominent climate forecast parameters, their outlooks and influences follow.

    1. ENSO: La Nina has entered a third consecutive year. Since 1950, 3-year La Nina episodes were observed in 1954-56, 1973-75, and 1998-2000. The 3rd spike in intensity of the 2020-22 La Nina is expected during November 2022. However, La Nina 2020-22 is likely to fade early next year. IMME weakens La Nina dramatically by February 2023.
    2. IOD: Note the very warm sea surface temperature anomalies (SSTA) north and northwest of Australia in the IMME forecast for November. The very warm signal in this region is known as the negative phase of the Indian Ocean Dipole (-IOD). The moderate-to-strong warming of the waters in this region are fueling widespread heavy tropical convection. The rising air currents are replaced by air at low levels of the atmosphere arriving from the east propelled by stronger than normal trade winds. The trade winds up-well cool waters to produce the 3rd year of La Nina. However, the -IOD pattern is gone by February 2023 and as a consequence, La Nina (also) fades.
    3. OCN: Not well-understood is the evolution of a persistent marine heat wave in the Northeast Pacific during 2013. The “warm blob” of shallow and deep layer water in this area (NEP22A) has persisted since that time and has influenced the upper-level atmospheric pattern(s) that cause our weather. Most specific, an enhancement of West Coast drought is related to this oceanic regime. Coincidentally, a large cool water zone formed at the same time south and southeast of Greenland in the North Atlantic. This persistent feature became known as the North Atlantic warm hole (NAWH) due to the surrounding tendency of anomalous warmth across most of the North Atlantic basin during the past two decades. The NAWH pattern has also caused significant impact on climate particularly Europe where semi-permanent upper-level high-pressure ridging has caused a milder winter trend and increased risk of summer drought. The influence of the Northeast Pacific marine heatwaves and NAWH pattern in the North Atlantic combine to produce an optimum climate normal (OCN) in which the climate pattern since 2013 is consistent across North America but quite different from the traditional 30-year normal. OCN (minus El Nino years) is heavily considered in the 2022-23 winter outlook.
    4. PDO/AMO: The Pacific decadal oscillation has been very negative during 2022 which is typical of a La Nina climate. However, the 2022 -PDO regime is quite different from previous similar patterns. Typically, waters off the U.S. West Coast are cool during -PDO. However, during summer 2022 the offshore waters warmed significantly due to the hot weather on the West Coast. -PDO remained intact as waters north and northeast of Hawaii are historically warm leaving the waters adjacent to the West Coast comparatively cooler. -PDO is likely to continue through Q1/2023. The warmer version of -PDO is likely to favor West Coast dryness rather than the typical wet Northwest regime of most winter -PDO regimes. In the North Atlantic, another unusual SSTA signature is present with the middle latitudes extremely warm while the southern latitudes are forecast to cool to normal. The warmth is strong enough to maintain a positive phase Atlantic multi-decadal oscillation which is a warming influence on the U.S. East Coast (and Europe).
    5. Northern latitude oceans: During the past decade, the OCN influence on northern hemisphere climate previously described has equaled and sometimes exceeded ENSO. Another fairly recent SSTA regime having significant influence on northern hemisphere winter is the warming of the high latitude ocean just-south of the polar ice cap. During late autumn/early winter as the northern latitudes cool down due to loss of sunlight advection snows become common and have a tendency to pile-up significant snow across the northern continents. After the piling snows have accumulated, cold air masses can pool over the snow cover and if the right pattern comes along these chilly air masses are released southward to produce “sneaky” early season chill in the populated mid-latitudes. If this process can become well established, a “polar vortex” winter pattern can develop. Conversely, just south of snow cover has a tendency to be very warm. Of extreme importance, is monitoring early season heavy snow cover in the northern latitudes and whether that snow cover shifts south as a guide to accurately project cold weather risk in North America and Eurasia.

    Fig. 7: IMME global SSTA forecast for November 2022 with annotated regions of influence on North America climate.

    Fig. 8: IMME global SSTA forecast for February 2023 with annotated regions of influence on North America climate.

    Forecast methodology: The October 2022 through April 2023 U.S. climate forecast is based on the influence of the regional SSTA described and as forecast by the IMME model. Analog years weighing most heavily is 2000, a 3rd La Nina year and the OCN (2013-2021 minus El Nino years).

    October 2022: Typical of autumn during a La Nina regime is the arrival of an upper trough across western North America. The October forecast reveals this pattern although forecast confidence is below average on the intensity of the upper trough. The CIC-CA forecast reveals a wetter regime for mid-autumn which should ease the tendency for late season heat waves in the West and Central U.S. The Northwest U.S. forecast is chilly and quite wet. If so, the intense dryness of late summer and influence on local drought should ease. Additionally, wet weather ahead of the Northwest U.S. trough also affects the Great Plains and Midwest States where late season drought concerns should ease. The prohibitive anomalous warmth across much of the U.S. during early autumn is still there shifting into the East for mid-autumn. Also typical of La Nina is the tendency for dry climate to develop in the Gulf States as indicated for October implying lack of late season coastal risk of tropical cyclone strikes.

    Fig. 9-10: The Climate Impact Company temperature/precipitation anomaly climate forecast for October 2022.

    November 2022: Late autumn brings another pattern reversal. The very warm pattern shifts westward in November. In the East, sneaky cool air from Canada is expected although moderating crossing the warm Great Lakes. The wet weather associated with an East U.S. upper trough is offshore leaving most of the East dry which is unusual for a November climate. The ridge pattern shifts westward causing the mid-autumn wet regime in the Northwest States to reverse much drier.

    Fig. 11-12: The Climate Impact Company temperature/precipitation anomaly climate forecast for November 2022.

    December 2022: Earlier in this report, the likelihood of piling snows across the northern continent was indicated. The December forecast implies the Canadian snow cover advances into the Northern U.S. by early meteorological winter enabling a cold start to the winter season for the North-central/Midwest U.S. To the south of the northern snow cover and attendant cold weather, the Southwest U.S. and Florida are exceptionally warm and the Northwest plus Mid-south States are very dry.

    Fig. 13-14: The Climate Impact Company constructed analog December 2022 temperature and precipitation anomaly outlook

    January 2023: As previously indicated, La Nina is expected to fade early in 2023. This process may arrive abruptly. During January, an eastward pulse of Madden Julian oscillation (MJO) convection across the equatorial Pacific is expected. The influence on U.S. climate is a classic January thaw. The anomalous warmth is strongest across the northern latitudes of the U.S. likely eroding snow cover established earlier in the winter season. Normally, an MJO surge would produce a wet regime in the West U.S. therefore the dry forecast for Oregon/California is made with below average confidence. However, the dryness in the East is reasonable. The MJO episode erodes the La Nina regime dramatically early next year.

    Fig. 15-16: The Climate Impact Company constructed analog January 2023 temperature and precipitation anomaly outlook

    February 2023: After the mid-winter MJO regime passes a compensating “polar vortex” pattern for late meteorological winter is expected. The episode produces a sharp cold change for the Central U.S. and a cold surge of arctic air is likely in this region possibly reaching Texas. The East/Southeast stays warm as cold air arrival is greatly moderated. A strong storm track is evident in the Mid-south U.S. to the Ohio Valley with significant snow across the west/north portion of that zone.

    Fig. 17-18: The Climate Impact Company constructed analog February 2023 temperature and precipitation anomaly outlook

    March 2023: Into early meteorological spring a La Nina climate may linger while oceanic La Nina dissipates. Consequently, mixed signals occur as related to ENSO climate. The Southwest U.S. including California stay dry and warmer than normal. The wet weather regime shifts to the northwest Gulf States. The northeast quadrant of the U.S. is the cold risk zone.

    Fig. 19-20: The Climate Impact Company constructed analog March 2023 temperature and precipitation anomaly outlook

    April 2023: Mid-spring is warmer than normal across the South and East while the northern Great Plains are chilly and wetter than normal. Texas is dry while the Southeast is a wet weather zone.

    Fig. 21-22: The Climate Impact Company constructed analog April 2023 temperature and precipitation anomaly outlook

    DEC/JAN/FEB 2022-23 summary: The meteorological winter 2022-23 HDD anomaly forecast indicates above normal heating demand across North-central U.S. while California and the Southwest U.S. plus the East/Southeast U.S. observe below normal heating demand for upcoming winter.

    Fig. 23: The Climate Impact Company constructed analog HDD anomalies for DEC/JAN/FEB 2022-23.