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I have starting reading some very simple Japanese news articles and came
across this sentence,

4日に出した予想では、今年一番早く咲くのは福岡市と高知市で、今月13日です。

While I'm relatively sure what the sentence means I'm unsure of the use of the
で particle in,

4日に出した予想では

I'm sure it's used to mark means of an action but I'm unsure of what action it
is marking and how it relates to the rest of the sentence.
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2021-03-09T11:49:27.167
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question
particle-で
usage of で in a sentence
I believe the「で」used in this sentence marks the location. More precisely, it
marks the source of information. So, you can interpret「4日に出した予想 **で** は、...」as

> **In** the weather forecast announced on March 4, ...

The rest of the sentence can be translated as

> In the weather forecast announced on March 4, the earliest time for sakura
> to bloom this month is on March 13 in Fukuoka and Koichi.
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2021-03-10T02:21:17.097
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answer
では in this sentence is a collocation of the ren'youkei of だ (which is で) + は,
which expresses that something is the premise of a declaration/judgment [1].

So Xでは here means "according to X" or "based on X", i.e.

> 4日に出した予想では、今年一番早く咲くのは福岡市と高知市で、今月13日です。  
>  According to the prediction given on the 4th, the earliest they will bloom
> this year is in the cities of Fukuoka and Kochi, on the 13th of this month.

Another example:

> 天気予報では明日は晴れるそうです。  
>  According to the weather forecast, it will be sunny tomorrow.

You can also substitute だと for では in either of these sentences; the meaning is
the same.

> 天気予報だと明日は晴れるそうです。  
>  According to the weather forecast, it will be sunny tomorrow.

[1] [デジタル大辞泉
(dictionary.goo.ne.jp)](https://dictionary.goo.ne.jp/word/%E3%81%A7%E3%81%AF/#jn-152205)

> **で‐は**  
>  ［連語］  
>  ➊《断定の助動詞「だ」の連用形＋係助詞「は」》判断の前提を表す。…であるとすれば。…だと。「雨では中止になる」「彼ではだれも承知しないだろう」
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answer