M.P.E.C. 2014-A02 issued on 2014 Jan. 2 at 13:08 UT reports the discovery of the asteroid 2014 AA (discovery magnitude 19.1) by Mt. Lemmon Survey (MPC code G96 ) on images taken on January 1.2 with a 1.5-m reflector + CCD. 2014 AA had an estimated size of 1.7 m - 3.8 m (based on the object's absolute magnitude H=30.9).

As reported on this MPEC:
It is virtually certain that 2014 AA hit the Earth's atmosphere on 2014 Jan. 2.2 +/- 0.4, as demonstrated by independent calculations by Bill Gray, the MPC and Steve Chesley (JPL). According to Chesley, the impact locations are widely distributed, most likely falling on an arc extending from Central America to East Africa, with a best-fit location just off the coast of West Africa on Jan. 2.10. 2014 AA was unlikely to have survived atmospheric entry intact, as it was comparable in size to 2008 TC3, the only other example of an impacting object observed prior to atmospheric entry.
Below you can see one of the discovery images of 2014 AA. The asteroid is the streak just left of center, surrounded by the purple circle.
Asteroid 2014 AA
© Courtesy of Catalina Sky Survey / NASA

Below you can see the two maps of the possible impact region made by Bill Gray.

Asteroid 2014 AA
© Remanzacco Observatory
Asteroid 2014 AA_1
© Remanzacco Observatory
These maps are based on half-arcsecond Monte Carlo noise. The corresponding impact times and locations are listed here.

The animation made by Pasquale Tricarico shows the Earth as observed from the asteroid 2014 AA, using the nominal orbit solution. In the background are visible the Sun and the Moon. The asteroid approaches the Earth from the night side, and enters Earth's shadow cone at approximately 01:45 UT of January 2, approximately 40 minutes before entering the Earth's atmosphere.

This is only the second time in history that an impacting object is observed prior to atmospheric entry. The first time it happened was with asteroid 2008 TC3. For more info about 2008 TC3 see our 2008 posts here:

Small Asteroid 2008 TC3 to hit Earth Tonight

2008 TC3 Animation

2008 TC3 Update - Impact Flash Imaged from Satellite

2008 TC3 Trail imaged over Northern Sudan!!!

2008 TC3 Fragments Recovered!!!