"especially welcomed" is correct and usable in written English.
You could use it when you are emphasizing a welcome or acceptance. For example, "Your offer of help was especially welcomed."
He will be especially welcomed this weekend in Sudan.
He especially welcomed Peres, reappointed Labour leader after Barak's resignation.
Women, who are everywhere prominent in Sufism, were also especially welcomed.
That is why this year's Nobel peace prize is to be especially welcomed.
I especially welcomed all my newfound physical therapy friends at the clinic, who replaced my tennis pals.
These plans have been especially welcomed by foreigners doing business in Saudi Arabia, who have been hamstrung by the capriciousness of the religious judges.
I'd especially welcome comments from those who have lost their jobs or have friends and relatives looking for work.
The Workshop especially welcomes applications from candidates with garlic pits, subscriptions to Maxim, and/or prep-school pedigrees.
We hadn't tamed Everest, of course, but the high-altitude treks had tested us nonetheless, making the comforts especially welcome.
"Murakami especially welcomes personal questions about his favorite cats or baseball team the Yakult Swallows," the representative said.
The last would be especially welcome.
