Highlight: Extreme early season cold next week North-central U.S. should lose intensity shifting eastward.
Chart of the day: Latest U.S. gas population weight HDD forecast.
Discussion: The U.S. gas population weight heating degree day (HDD) forecast through the first third of November projects much below normal heating demand for the current week shifting to near the 30-year normal for late October and early November. The increased heating demand begins as November arrives in the high demand Northeast U.S. and gradually into the Mid-Atlantic States. The GFS OP is the coldest model into the East U.S. The ECM OP and ECM ENS are the least cool forecast. The colder pattern ahead is best supported in central North America which includes some snowfall to enhance the cold. The leading support for cold weather across the Canadian Prairies to North-central U.S. for late October is an amplified negative phase of both the East and West Pacific oscillation (-EPO/-WPO). However, support by climate signals for the colder weather shifting into the East is weak as WPO/EPO trend is flatter and the North Atlantic oscillation (NAO) is weak positive.
Medium-range 6-10 Day Forecast Valid October 25-29, 2023
Discussion: Continuing to combine the colder GFS and less cold ECM to generate the medium-range forecast. The East remains warm while arctic cold is generated upslope the Montana Rockies.
Medium-range 11-15 Day Forecast Valid October 30-November 3, 2023
Discussion: The GFS and ECM combine to push the colder pattern eastward but losing intensity leaving the source region. The Great Basin and Southwest rewarm.
U.S. Medium-range Precipitation Forecast
Discussion: Heavy rains remain in the forecast for Texas to the Midwest U.S. in the 6-10-day period while heavy snow is likely in Montana to the northwest Great Plains. The 11-15-day forecast is drier.
Days 16-20 Extended range Temperature Forecast valid November 4-8, 2023
Discussion: The extended-range forecast is generated with below average confidence. The GFS and ECM ensembles end their 15-day forecast cycle pointing in a warmer direction therefore the warm CFS V2 is the selected model although the northern tier could be cooler.