EMB ERJ 145 ER/LR
Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence; Inflight Event / Encounter Fuel Issue; Inflight Event / Encounter CFTT / CFIT
Flight Crew Diverted
Human Factors; Weather
We were flying to ZZZ with an alternate of ZZZ1. Weather at the time of Takeoff was below minimums for the approach; but was worse than forecast. We went to ZZZ slowly hopeful for the weather to improve. It did not. We planned for a hold at ZZZ at 20;000 feet. On the way dispatch added the alternate of ZZZ2. We looked at the weather at both alternates on the way to ZZZ and both seemed acceptable. We came up with and were in agreement on bingo fuel for both alternates. We then decided that we would take ZZZ2 as the alternate giving us slightly more time to hold for weather to improve at ZZZ.  Weather finally came up to 1;800 feet RVR and we were able to shoot the Monitored approach to ZZZ1. We had all briefings done and had decided we would try the approach and any missed would be an immediate diversion to ZZZ2. I then took over control of the airplane as pilot flying. At DA we went around and immediately headed to ZZZ2. On the way to ZZZ2 we opened the brick and began preparing to go to ZZZ2. I prepared for a Approach and took care of the checklists got weather informed Dispatch; Flight Attendant (FA); and Passengers of out intentions. We flew a GPS approach to 22 in ZZZ2. When I got to DDA there was nothing in sight. I preformed a missed approach and as we were climbing out we both decided that we did not have enough fuel and that we must fly the plane lower to ensure landing. ATC offered us two airports and we both agreed that they were to far; and that we did not have enough information. We got the weather in ZZZ2 and it was still 700 OVC and 10 Miles Visibility. We decided on an altitude that we would fly to and got vectors to shoot another Constant Angle on a Precision Approach (CANPA) this time it would be to lower then the MDA if it had to be. Using our emergency authority. We communicated during the approach making sure I knew exactly where I was in relation to the GPS derived glide slope. Unfortunately we had to come down to approximately 400 AGL before we were able to see the field visually. We then made a safe landing after finally seeing the airport.  We had to many threats to even mention. We had just met and seemed to be on the exact page of calling out threats working together and making decisions together. Ultimately we ended up in the undesired aircraft going below MDA on a GPS approach.  We were both of the opinion that we would do exactly the same thing again if faced with this horrific situation. The only change we would have made is that we would have opened the Brick sooner and looked at the airports and the approaches available while en route. We chose not to because we didn't want to open it until we needed to. We also would have stuck with our first alternate and just disregarded the addition of another alternate for a small amount of holding fuel.
EMB-145XR First Officer (FO) reported diverting to an alternate after an unsuccessful approach that resulted in very low fuel state and CFTT on the subsequent approach.