AUG 13 - A few changes from the JUL 10 update. Bumped confidence to NORMAL. Here are some things to watch teleconnection-wise:
- QBO index is stuck around 0...was expecting a negative to QBO to develop as historical tendency suggest but has not. The only major teleconnection I failed to predict in JUL. I'm keeping it at 0 through OCT 2020 but no doubt it will trend either pos/neg during the winter months. Hard read atm.
- PNA has been leaning positive so added into this version whereas previous forecast did not.
- Questioning what the AO trend will be? Currently hovering around neutral as it should in summer.
TEMP - Strong signal for ABOVE AVERAGE TEMPS. Shifted warmer than average east into Great Lakes/E US from previous forecast. I HAD Wisconsin at [A] so no change for us. 500mb analogs suggests positive height anomalies over the Great Lakes similar to JUL 2020. Mostly consistent with JUL 10 forecast so confidence is GOOD in this regard.
500mb anomaly map for SEP 2020 based on analogs. Note weak neg signal over NW PAC as possible source for wetter signal over N IA.
Corresponding SEP 2020 TEMP anomalies based on analogs.
PRECIP - Analogs are trying to tell the story a stormy pattern across northern Iowa into SW WI. It's tied to the [A+] tendency over southern IA...suggests heat will be present to kick of t-storm events in the region. Will that occur EXACTLY as shown in the maps? Maybe. Sometimes this pattern is shifted north or south. This forecast deviates from the previous dry signal in southern WI...however dry signal remains across northern WI; also IL [& points SE]. Regarding [B] in northern WI...JUL/AUG likely to be wet up there...might be time for that pattern to shift out?
OVERALL, a lot more detail in the SEP 2020 forecast than typical. Will see how it plays out.
JUL 10 - Confidence is low. This is my first attempt at FALL monthly forecasting.
This pattern indicates that upper troughing from AUG will move east into the Atlantic/Meridian zone replaced by more relaxed zone flow over North America...likely warmer than average across much of the United States. Perhaps this pattern is not the entire month or falls at the beginning or end?...regardless of timing it should contrast (be mirror opposite) of the AUG pattern. Unknown what this will lead to in OCT.
TEMP - Above average
PRECIP - Below average...pretty strong signal across southern WI. Lacking of troughing; lacking low pressure systems from the west/southwest? This could also suggest preference towards scattered convective thunderstorms...especially if the month is warmer. We'll see!
SEP 500mb anomaly featuring more relaxed, warmer, zonal pattern.
I kept the strong positive AO years of 1989-1990 in the analog list. Debated removing; probably will take out of OCT 2020 forecast. AO tends to reset this time of year.