Date: 201902
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: IMC
Weather elements / visibility: Rain; Thunderstorm
Light: Daylight
Aircraft: EMB ERJ 170/175 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class B ZZZ
ATC / advisory: TRACON ZZZ
Reporter organization: Air Carrier
Reporter function: Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown
Anomaly: Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence; Inflight Event / Encounter Fuel Issue
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Diverted; Flight Crew Landed in Emergency Condition
Contributing factors: Weather; Company Policy
Primary problem: Company Policy

Narrative: Declared [minimum fuel] after weather deteriorated at destination. Exercised PIC (Pilot in Command) authority to divert to ZZZ1 when no Alternate was listed or required. We were very tight on fuel from the time we departed ZZZ2; but met the requirements of our release. Our release showed ZZZ2-ZZZ; MT 7700; ALT (Alternate) not required and contingency fuel of 200lbs. We sent 7.9FOB (Fuel On Board) to [the load planner]. [After] we pushed back from the gate I queried Dispatch about being so short on fuel; and they replied (paraphrased) that the load planning was biased towards minimum fuel out of ZZZ2 for noise abatement. I understand the desire to be good neighbors in ZZZ2; but no alternate and 200lbs contingency fuel do not work for routes that include ZZZ. We were given a short delaying vector enroute by either ZZZ3 or ZZZ4 Center; but still showed 3200FOB on landing. Once on the ZZZZZ arrival to ZZZ; ATC slowed us down early to increase spacing. A line of cells began moving across the arrival and approach corridor; and a couple of minutes later Approach informed us that the two preceding aircraft on the arrival had been struck by lighting and turned us to the southwest; off the arrival. We immediately declared minimum fuel; the First Officer asked Dispatch via ACARS (Aircraft Communications Addressing and Reporting System) where they would like us to divert and we asked [Approach] to stand by while we formulated a plan. I asked [Approach] how long the vectors would be; and they replied 35-40 miles. We did not have fuel for 35-40 miles of vectors off course and then back; the cells were moving towards ZZZ4; Dispatch hadn't responded and we were in moderate turbulence and precipitation; so I exercised PIC authority; we declared [minimum fuel] and requested immediate diversion to ZZZ1. [Approach] immediately started vectoring us towards ZZZ1 and told us to expect ILS30L. We were in moderate turbulence and precipitation while reprogramming the FMS (Flight Management System). When we were done programming; the FMS showed 2600FOB; versus our reserve fuel of 2900. The flight attendants were notified that we were diverting to ZZZ1; but the passengers were not because we were simply too busy. We completed the ILS XXL and touched down with 2540FOB. ZZZ1 had rolled the trucks for us; but we never requested that. When we cleared the runway; I briefly addressed the passengers and told them that I would give them a more thorough briefing when we were at the gate. We arrived at gate XX; I spoke with the passengers from the front of the cabin and then walked the aisle to answer questions. After conferring with Dispatch and ZZZ1 station; we canceled the flight and deplaned the passengers about 20 minutes after arriving at the gate.A recommendation that I've made before; and that certainly applies here; is to add more contingency fuel if you're going to not require an alternate. 200lbs of contingency fuel lasts approximately two minutes while flying at low altitude. This is not a good plan or 'best practice'; especially at airports where delays are the norm.




Synopsis: EMB175 Captain reported declaring minimum fuel when weather deteriorated at destination and diverted to another airport.