The new moon for Ramadan 1430 comes in, according to www.nevis.columbia.edu, on Thursday August 20th, at 5:02 AM EST. Therefore the Ramadan moon has already been born and whether one begins fasting depends on what method of determining the beginning of Ramadan one accepts, or which mosque or school of thought one follows, or for Shiâ€™a it depends on which marja they follow.
By FCNA/ ISNA calculations, this new moon is impossible to spot in Mecca after sunset on Thursday, therefore although the new moon is in it is deemed by the reasoning of the Fiqh Council to bring in Ramadan the following evening. Therefore FCNA will begin fasting on Saturday, tarawih prayers on Friday. Many American mosques follow the influential ISNA / FCNA calculations.
Other mosques follow ICNA, which has a different means of calculation. Hamza Yusuf and Zaytuna insist on local physical sightings of the moon. Many American mosques follow specific countries, without adhering to what other local mosques are doing.
Saudi Arabia will fast Saturday, tarawih prayers beginning Friday.
In the coming days insha`Allah we will report on when different communities began their fasting.