Date: 201906
Local time of day: 0601-1200
Location: ZJX.ARTCC, FL
Flight conditions: Marginal
Weather elements / visibility: Thunderstorm; Rain
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise; Descent; Climb
Airspace: Class A ZJX; Class E ZJX
ATC / advisory: Center ZJX
Reporter organization: Government
Reporter function: Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Workload; Situational Awareness
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Other / Unknown
Detector: Person Air Traffic Control
Result: Air Traffic Control Separated Traffic; General Flight Cancelled / Delayed
Contributing factors: Airspace Structure; Company Policy; Human Factors; Staffing
Primary problem: Staffing

Narrative: I walked into the Control Room to start my shift and the Controller working [two combined sectors] was shouting at the Supervisor that he 'really needs this split now.' I was given a verbal weather briefing to save the time of watching the mandatory briefing prepared by our CWU (Center Weather Unit) so that I could immediately split [the] sector. At the time I assumed the position; there was moderate traffic and a large area of weather in the sector which was confining all of the north and southbound traffic to a corridor approximately 15-20 miles wide in the northern 2/3 of the sector. There was 20 miles in trail to FLL posted; and 15 miles in trail to MIA pending. The Atlantic routes were closed and all that traffic was also flowing through our hole in the weather.As the morning push continued to build; and two additional FLL departures were released off of CHS into a mix of other FLL landing traffic which were already going to require vectors south of the weather to achieve the required 20 miles; the complexity in the sector began to build significantly. At some point; I believe I was given a D-side and [another sector] and I began working to establish some sort of a start on the south Florida spacing for the controllers to our south. Our Supervisor was coordinating heavily with the east area to try and ensure that any additional FLL and MIA traffic coming into [our area] was in trail or routed down the middle of the state to ease the burden on those sectors; but in between doing that; I noticed he was also spending a lot of time at [another] sector; essentially acting like his D-side. This was when I looked at our break list and realized that every Controller in the south area was currently plugged in working traffic. Over the course of the next hour or [two]; I heard 2 different controllers ask for D-sides; only to be told that nobody was available for them. However; the traffic and complexity in my sector continued to build and would eventually be flowing in their direction.We were told that TMU (Traffic Management Unit) had gotten some relief on the MIA and FLL spacing; but by this point it was almost moot; as it had become almost impossible to keep track of the sequence between the MIA; FLL; and MCO traffic between me and the high side; given the volume and weather deviations as well as the aircraft being added into the mix further south from [other] sectors. The Controller working [the adjacent] sector at the time is; [in] my opinion; a very strong Controller and one whom I have seen work through some very difficult situations with relative comfort in the past. Controller had no D-side; and was taking my handoffs progressively closer and closer to the boundary as the session wore on. While Controller never refused a handoff from me; I could tell that Controller was working right at the limit (and again; in my opinion; well beyond the safe limits for any Controller without a D-side). I made the decision to place a FLL lander who was tied with another with a third behind that into holding. I also began descending all of my MCO landing traffic to get under all of the overflights and vectored the next three due east for a couple of minutes to give Controller a little gap in the stream for some 'breathing room.'The traffic continued to be very heavy and extremely complex for approximately an hour; and I released my D-side to go help at [the other sector] well before I would have normally released a D-side; simply because Controller needed it more than me and there was nobody left in the building to help Controller. Traffic and complexity continued to be very high through about noon; but at least we had staffing to appropriately deal with it after that first session of the morning. I should also note that I walked into the Control Room with the Controller who wound up working [the adjacent sector] during that session. Controller had been there since 6 and told me Controller was told to take a 15 minute break because our Supervisor knew that he'd need Controller to open a sector soon. Upon speaking with my area representative after the incident; he was told by our Operations Manager that ZJX TMU had requested a [flow program] and was denied by the Command Center.Our staffing numbers are lower than we have ever had in all my years at ZJX. We routinely drop our schedule with 8 or 9 controllers on a shift. While we controllers like to complain about having less or shorter breaks due to staffing; the reality is that on most days we absolutely can run the area with numbers this low. That being said; when there is weather or volume - neither of which are exactly uncommon in the south area at ZJX; there are times when we simply do not have the bodies to staff the positions necessary. We have 6 sectors and when it is busy; it is not uncommon to have a D-side at 4 of them and possibly a tracker somewhere too. In fact; when I came in for my midnight shift tonight; I was told by the night shift that at one point they had 13 people plugged in. We probably should have had 10 or 11; but I think we only had 8 or 9 at work at the time this morning. I feel like if the Agency is committed to running the area on bare-bones staffing; then they need to be committed to taking the necessary action required in the instances when it becomes unsafe to continue running the volume through an understaffed area. It is completely unacceptable that drastic and immediate action is not taken when two different sectors ask for D-sides and nobody is available to help.




Synopsis: ZJX Controller reported a shift working combined sectors due to lack of staffing during periods of weather deviations that created an unsafe workload.