Today’s video:
Holiday Schedule of Updates:
PDF report (click link to the right to open in HD): 12-23-19 Long-range analysis
Key Points:
- Relatively inactive pattern persists this week. A storm system will develop later this week into the weekend with heavy precipitation possible in the Southern Plains.
- Widespread warmth likely for Christmas Week. Many areas see a top 5 warmest Christmas on record.
- We are sticking with the warmer idea into the week 2 period. The MJO looks to linger in phases 6/7 which are warm phases, the AAM is positive and the cold air source is on the other side of the planet.
- Overall the major pattern drivers suggest warmer risks for the week 2 period with only minimal cooler risks.
- We anticipate the sub-tropical jet to remain active keeping the south/southeast wet.
Weeks 1/2 temperature outlooks:
Week 1:
- Very warm period through the Christmas Holiday leading up to New Years, especially focused across the Midwest through the Missouri/Tennessee Valley.
- This period has roll-forwarded quite a bit warmer vs previous week 2 forecasts due to the slow progression of the MJO through the warm phase 6.
Week 2:
- MJO Phase 6/7 lingering influence continues to keep the northern to eastern half of the US at a higher risk for above normal warmth to end December and open January.
- Also, looks like we are losing any cold source via the Polar Vortex, moving the cold lobe to the other side of the Planet.
- The EPO has yet to flip to negative, resulting in more moderated Pacific air to filter further into the US by an extended jet stream.
- For January as a whole, the cold risks likely won’t return again quickly unless the MJO finally gets into phases 8/1/2, AAM goes more negative and the cold lobe of the PV returns to this side of the planet.
Weeks 1/2 precipitation outlooks:
Week 1:
- Heavy rainfall in the SE US today into Christmas Eve.
- Otherwise, not seeing any widespread precipitation risks to the central US to Midwest until early next week with a low pressure system working west to east.
- At this time, system looks to lack much wintry potential with how warm this period is.
Week 2:
- Due to persisting ridging in the week 2 forecast & increasing El Nino tendencies, we foresee a continued inactive forecast / jet stream influence from the West Coast through the central Plains to the Midwest.
- We foresee the PNW to the southern US to SE to Eastern US to remain active with an increased subtropical jet stream influence.
Updated January forecast:
Temperatures:
- Based on the continued warmer trends into January we are changing up our forecast thoughts. Following the breakdown of the +IOD we have allowed MJO convection to re-develop in warmer phases. This will allow for a very warm start to January.
- The Polar Vortex is also situated on the other side of the globe preventing the CONUS from tapping into a real source of cold air. Continued westerly momentum deposited into the North Pacific will allow for a strong Pacific jet and more mild opportunities for the Eastern US.
- Overall, the latest CFS weekly data is closely resembling composites for similar Stratosphere PV orientations with warmer risks favored in the east/southeast.
- Closest ENSO matches with warmth across all ENSO regions are 2019 and 2007. We are running closely to last year right now in both terms of actual weather and the MJO so we leaned towards that idea with SE warmth being more prominent, though we note we would not be shocked if the North-Central US to Pac NW could trend warmer based on the start of the month and years like 1992 (MJO Analog) and 2007 which featured more warmth in the Central/Pac NW.
Precipitation:
- No real adjustments to our precipitation outlook as we still anticipate more of a split jet signal in January. This is typical of more Niño like forcing and given the ample westerly momentum being added the Pacific we think we can continue to see this split jet with the sub-tropical jet being the dominant moisture source.
- Phasing issues and lack of cold air will likely be a problem for January wintry risks – though if we could feel more MJO phase 8 towards the second half of the month it could allow for at least a little more cool air to work with for wintry chances in the Ohio Valley and Midwest.
- Biggest risk to this forecast is the potential for the Northern jet to be displaced so far north that the Central US could trend drier with mainly cold rain events in the SE US.
Updated early/mid Jan pattern drivers:
Updated Jan-Feb-March pattern drivers:
