Today’s video:
BAM Forecast update Holiday schedule:
PDF report (click like to the right to open in HD): 12-20-19 Long-range analyis
Key Points:
- Very inactive pattern for the majority of the country the next 7 days with little to no precipitation chances. SE Coast/West Coast sees only precip chances.
- Warmer air will spread from west to east late week 1 into week 2 as a strong Pacific jet floods more mild air into the country.
- As the jet retracts it will favor the development of a –PNA and help push warmth eastward.
- MJO phase 6 risks favor more notable warmth as reflected in our updated week 2 outlook
- Latest Week’s ¾ outlook à trending warmer given +AAM, slow MJO progression and warmer MJO analogs.
- As we start to get more active late week 2, storm track probably initially returns to the Plains with wetter risks there.
Weeks 1/2 temperature outlooks:
Week 1:
- Warmth is now widespread across the Country as we head into the Christmas Holiday.
- Locations in the Northeast remain one of the few locations to average out normal to slightly below normal.
- As week 2 denotes below, the warmth will continue to trek east for week 1 this weekend.
Week 2:
- MJO Phase 6 lingering influence continues to keep the eastern half of the US at a higher risk for above normal warmth to end December and open January.
- The data has started to add cooler risks at the end of week 2 over the past 2 days, which would be possible given more trends towards a –EPO (ridging near Alaska).
- We still are quite cautious with mentioning widespread colder risks into the first week of January due to an increasing +AAM trend (this can extend the Pacific jet stream and push more warmer air into the US).
- The cold risk into early January, however, is it’s possible the data is not quick enough pushing into the colder MJO phases of 8/1 combined with continued –EPO / -NAO trends.
Weeks 1/2 precipitation outlooks:
Week 1:
- A very quiet and rare dry stretch across the entire central US is expected to continue leading up into Christmas.
- The SE US looking to turn quite active with heavy rainfall / flooding risks into early next week.
Week 2:
- With the continued modeled solution of ridging being positioned in the East to Southeast into week 2 + increasing the subtropical jet stream influence, the storm track looks to shift back to the central Plains to the Midwest and Valley areas.
- Availability to cold air is still in question for any notable wintry systems, but leading up to New Years there will be an increasing *potential* for wintry weather in the Plains to the Midwest.
Weeks 3/4 updated outlooks:
Temperature:
- The theme heading into the first half of January has now transitioned to warmer risks for a good portion of the central US to SW Canada, cooler risks from the SW US to generally the southern tier of the US with an increasingly active subtropical jet stream.
- El Nino influences look to increase across the equatorial Pacific in this timeframe, along with the AAM (atmospheric angular momentum) looking to trend more with a positive influence as well.
- We are also looking to, for a time, lose the cold influence from the Polar Vortex, which can limit the extent of the cold source here for the US in general.
- The colder risks for temps in this period is if the EPO trends more persistently negative, as does the NAO and we swing into MJO phases 8,1,2 quicker, the Eastern US could trend colder quicker.
Precipitation:
- Our weeks ¾ precipitation forecast is an extension, once again, from our week 2 forecast with the southern tier of the US staying active with a continued active subtropical jet stream due to increasing El Nino tendencies globally.
- This can make things overall drier from the PNW to the north-central Plains and upper-Midwest as we reorient the northern Polar jet stream and increase higher upper-level heights more consistently over the area here.
- In terms of wintry weather potential for the Plains to the Midwest and Ohio Valley, we still think there are going to be chances, but with the lack of a major cold air source it’s possible this shifts more South and to the East Coast.
Updated pattern drivers into early January:
Updated Jan-Feb-March pattern drivers:
