I feel that there has very likely already been a significant irreversible loss of potential (i.e., ceiling has been lowered) in the prime S MG/Mogiana area. Here's why:
1. Despite the weather models predicting well above normal rainfall since ~10/8 (the first day of rains after that 2 week long very hot, dry period) in the prime S MG/Mogiana area, the rainfall anomaly map of the last 30 days shown below says in reality that rains were sporadic. There were 2-5" deficits dominating with mainly only 1.5-4" falling vs 5-8" norms (dark brown spots in middle of this prime area were 90+ mm too low, which is a whopping 3.7+" below norm). The avg. deficit was >50%. Coming right after that very hot/dry 2 weeks as well as dry Apr-Sep overall, I don't see how that couldn't be a significant lasting negative for the 2020-21 crop potential:
Also, note on that map that Cerrado also has a good portion in brown shade #2 with a smaller portion near normal and only a tiny part (far E portion) wetter than normal. So, on avg, this area was also drier than normal though not as dry as regions S MG/Mogiana. So, my focus will be on S MG/Mogiana.
2. Now, I'll present some actual rainfall totals to back up that map.
A. From Sismet Cooxupe, here are October totals (sorry this looks funny, but I had to do printscreens to save this in this form):
B. Now, here are totals for the first week in November:
(I'm ignoring "General Fields" and "Mount Carmel" as I can't find where they're located. Also, there were four at the end of the list that I left off because I couldn't find the location though I'm pretty sure none are in S MG/E SP.)
(Coromandel is in Cerrado and was near normal in Oct although dry so far in Nov.)
So, we're left with Alfenas, Alpinopolis, Cape Verde, Carmo, Guaxupe, and Mount Santo, which are all in S MG; and Caconde, which is in Mogiana.
3. Analysis of the S MG/Mogiana data:
We have for Oct 1 through Nov 7th the following in mm:
- Alfenas: 75 vs ~125 norm; so, 60% of norm
- Alpinopolis: 33 vs unknown norm; I'll educatedly guess ~25% of norm
- Cape Verde: 61 vs ~160 norm; so, 38% of norm
- Caconde: 67 vs ~210 norm; so, 32% of norm
- Carmo: 112 vs ~165 norm; so, 68% of norm
- Guaxupe: 35 vs ~155 norm; so, 23% of norm
- Mount Santo: 101 vs ~175 norm; so, 58% of norm
So, the average of these seven S MG/Mogiana stations was only 43% of the norm!
In stark contrast, the model consensus repeatedly suggested over 100% of norm for October much of the time. So, the model consensus was about twice as wet as reality.
Keep in mind that the area went through a 2 week long dry period with very intense (including records) late Sep/early Oct. heat as well as a significantly drier than normal April -Sep. overall period. I find it hard to believe that many nonirrigated farms didn't have many flowers abort in October.
1. The models have clearly been wet biased in S MG/Mogiana, possibly due to dry subsoil, and that may continue. So, it may be best to assume rainfall there will verify lower than model consensus suggests at least until if/when the models start verifying more closely.
2. When considering all of the above weather for April-November 7 in S MG/Mogiana, I can't see how there hasn't already been a significant and largely nonreversible reduction in the potential maximum size of the non-irrigated portion of the next crop.
3. The model consensus suggests Nov 8 will be the last dry day of the current streak with good rains Nov 9th and onward for awhile. I'm very wary about the degree of wetness they have as it is similar to how they looked when wet in October. Let's see how they do this time.
4. Even if normal or even above normal rainfall were to return the rest of November, I don't see how that would reverse most of what I think is an already largely irreversible reduction in potential. Rain would still help but I see the ceiling remaining significantly lower than it was originally.
5. I'd be skeptical about any new pics showing good crops with healthy flowering in S MG/Mogiana. I'd have to assume those are from irrigated farms, they're isolated anomalies from the very few farms that got near normal rains, or they're not really current pics from S MG/Mogiana.
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