6-10 Day Weather Forecast
GFS and ECMWF guidance is in agreement on a very warm 6-10 day period with the center of that warmth occurring over the Midwest into the Upper Midwest. The combination of the Polar Vortex being over the Arctic and the active Pacific Jet will allow a ridge to extend across the majority of the CONUS. As the trough over the Gulf of Alaska moves out we will begin to see the pattern back to close to normal.
11-15 Day Forecast
The ECMWF and GFS guidance are similar with the temperature departures for this period, but they arrive at the conclusion differently. The ECMWF guidance is showing a phase 1-2 tropical forcing while the GFS is looping back to phase 7. Both would favor a shift back to near normal to slightly colder conditions across the Eastern US. However, with the AO not budging from positive any cold won’t lead to any negative departures across the majority of the Eastern US.
If the GFS is right we begin to see a deeper Aleutian trough and a stronger ridge over the Gulf of Alaska which brings back near normal to slightly below average conditions to the Eastern US. If the ECMWF is correct a deeper trough should trend on the guidance across the Central and Eastern US.
Beginning part of the forecasting period will continue to see the ridge over the Eastern US that is enough to skew the departures towards above average in the East and below in the West. This will shift with the day progression in the next outlook.
Source: True Weather