11/29/2021, 5:13 am EST
Regional SSTA patterns are attached to local weather regimes including Argentina/Brazil and Australia heading into meteorological summer in the southern hemisphere.
11/28/2021, 1:17 pm EST
ost prominent in today’s medium-range forecast are the reversal in the North Atlantic oscillation/Pacific North America pattern(s) beginning later this week and indicating warmth in the West fades while emerging across the eastern half of the nation. The -PNA pattern should also lead to an increase in rain and snow in California in the extended-range.
11/28/2021, 10:01 am EST
Climate Impact Company continues to stress recent emergence of warm SSTA regions outside of the tropics commonly referred to as “warm blobs” and their influence on the regional (and hemispheric) climate patterns which are as important as the influence of ENSO. The character of climate patterns associated with “Warm blobs” is slow-moving and therefore more impactful.
11/26/2021, 10:11 am EST
Given the tendency for Covid-19 spread with established cold weather regimes in high population areas the importance of cold weather monitoring has (of course) increased. The 15-day outlook for Europe identifies an established cold weather risk which could be enhanced by developing snow cover and supported by a super negative Scandinavia Index pattern centered on days 6-10 ahead!
11/26/2021, 8:36 am EST
The Canadian Operational model identifies a swath of heavy rain in the 5-day forecast extending from north of Hawaii into the Canadian West Coast and Washington. The 5-day forecast indicates over 10 in. of rain in this zone with high spots approaching 20 in. Widespread flooding complicated by high wind strikes Washington (and northward)!
11/24/2021, 8:39 am EST
Agreement between both the GFS ENS and ECM ENS on stratospheric warming over northwestern portions of North America is indicated. Stratospheric warming indicates potential for arctic air development at ground level as the stratosphere warms and expands and the weather atmosphere beneath (troposphere) contracts and cools. Developing arctic air in 15 days can be difficult to project by operational models. However, the caveat 2 and caveat 3 version of the mega-cluster ensemble indicates arctic air is present and possibly heading for the U.S.
11/22/2021, 11:48 am EST
Heading Into meteorological winter where is the early season cold air mass source region? Typically, early winter brings gathering arctic air masses in Siberia but not this year. The frigid and snowy early winter regime is locked-in over Alaska. Pieces of this air mass have ejected into the East U.S. in the current pattern although that risk is likely eliminated once we're into December.
11/16/2021, 1:09 pm EST
The negative North Atlantic oscillation (-NAO) is impressive…surging toward -3.00 later this month. Implied is storminess and following cold into the East. The 12Z GFS has less of a storm for next week in the Northeast. The Scandinavia Index drops to -4.00 to -6.00 which indicates an unusually cold trough for Northwest Eurasia which will include cold temperatures and snow for that region.
11/15/2021, 4:53 pm EST
Today’s North Atlantic oscillation (NAO) forecast intensifies into the strong negative phase for next week signaling a high latitude blocking pattern forcing a Northeast U.S. storm featuring extreme intensity. Both the GFS and ECM project 970 MB low-pressure which could produce another intense wind event for the northern Mid-Atlantic and New England States for early-to-middle of next week, just before the Thanksgiving Holiday.
11/15/2021, 4:14 am EST
Widespread heavy rain occurred last week in Australia. The aerial coverage and intensity of the rainfall was likely the wettest in the seasonally wet climate pattern currently occupying the continent. Rainfall amount of 4-6 in. was common in southeast Queensland and (more) spotty in eastern New South Wales.
11/11/2021, 12:53 pm EST
Inevitable is the likelihood of the feared polar vortex pattern in January 2022. Why? Simply stated, there is precedent for persistent high-amplitude high-pressure ridge areas forming over large regions of much warmer than normal SSTA during the past 10 years in the winter season. Implied by the International Multi-Model Ensemble (IMME) are high-amplitude high-pressure ridge areas across very warm regions of SSTA just east of the Dateline and across western and central North Atlantic. In-between the two ridge areas, the atmosphere (always looking for balance) compensates by allowing a cold upper trough (polar vortex) to form over central North America.
11/09/2021, 4:40 pm EST
Of interest is a steady negative phase of the Asia/Bering Sea/North America (-ABNA) index coupled with a steady negative phase of the West Pacific oscillation (-WPO). The potential result is very cold weather in the 11-15-day period.