Date: 201606
Local time of day: 0001-0600
Location: ZDC.ARTCC, VA
Flight conditions: VMC
Weather elements / visibility: Thunderstorm
Light: Daylight
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Descent
Airspace: Class A ZDC
ATC / advisory: Center ZDC
Second aircraft: B737 Undifferentiated or Other Model
Reporter organization: Government
Reporter function: Enroute
Human factors: Situational Awareness
Second reporter function: First Officer
Anomaly: ATC Issue All Types; Inflight Event / Encounter Weather / Turbulence
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert
Contributing factors: Aircraft; Human Factors; Weather
Primary problem: Human Factors

Narrative: Aircraft X deviating well north of his intended route via J42 GVE and on his present deviation was going to take him in near vicinity of weather I was showing on my radar scope; which I described in detail to him. I feel he was going this far off course to gain a more direct routing down route. Aircraft Y checked on frequency at FL330 requesting higher [same company; same last two digits of flight number]. I issued FL340 to Aircraft Y and thought he acknowledged the clearance. My next instruction was to switch frequency to Aircraft X to next sector. After this I observed Aircraft X leaving FL350. I alerted the sector controller and he was already correcting the altitude of Aircraft X. I went back to Aircraft Y and verified he was climbing to FL340 which he again acknowledged. Aircraft Z was also on J42 via GVE at FL350 and I asked him for a PIREP. He stated he was in smooth air and cloud tops were 10;000 feet below him. We need more predictable deviation expectations from pilots.


Second narrative: We were in cruise flight at 35;000 feet. We already had to request several weather deviations due to the building thunderstorms on our route. We were able to remain mostly VMC during cruise and use both the radar as well as just looking out of the window for our deviations. At one point when we were still to the west of MOL VOR; we could see several build ups approximately 80 miles ahead of us and asked for left deviations in order to remain on the upwind side of the cells. The winds aloft were 315 at 78; and the cells were growing quickly. As we got closer we were cleared direct to GVE when able. A short time later; the Controller came on and asked what we were planning; and wanted to know if we could still make the turn to GVE and if not; what the plan was. The Captain explained our plan to continue left of course for another 40 miles and then try and make the turn back to the right. At this point we were probably 45-55 miles west of GVE; so unlikely that we could make it around the cell and still come back to GVE. The Controller told us that he showed the thunderstorms at our 12 o'clock and 40 miles right where we were deviating; and said it looked clear going back to the right. However looking out of our window; there was a lot of blow off to the right and looked like it would be rough on the downwind side and that we would stay completely clear of the weather on our deviation course. The Controller seemed a little annoyed that we wanted to continue on our deviation course; and it seemed like he maybe thought we were just trying to shorten our route. However our deviation kept us completely in the clear and we were able to actually have a smooth ride around the weather. The Controller then told us we were cleared direct OTT VOR when able. It was not long before we were able to make the turn back to OTT and didn't think much of it. A few minutes later; the Controller told us we needed to copy a phone number and call his Supervisor when we landed in BOS. We were cleared to deviate to the left for weather. We did not take his suggestion to go right; but he did not amend our deviation clearance; so I'm just not sure what to think of the situation. We were maybe a little slow getting him a good answer when he wanted to know if we could make it to GVE as we were trying to find a fix we could fly to that would keep us clear of the weather. But not anything that I could think of that would constitute a phone call.Also of note; is that just before he handed us off; he cleared us to FL 340. We read this back; but then later when we switched over to the new Controller they said they weren't sure why we were descended and climbed us back up to 350. Maybe the original Controller mixed us up with someone else or didn't hand the information on in the hand off. It could have also been a similar call sign and we read back someone else's clearance; but it sounded fairly clear. I admit that I was probably a little agitated over being given a phone number to call.I feel like we did a good job maneuvering around the weather and providing a safe and smooth ride for our Passengers. I also feel like we asked for the required deviation clearance; but there must have been a breakdown somewhere in communication with ATC that caused a problem that the Controller felt warranted giving us a number to call.Processing through this event; there are a couple of things I thought might help me in the future with similar situations. This was in a [older model aircraft] which has a greatly reduced amount of situational awareness. It is much more difficult to put the big picture together with regards to knowing where exactly the weather is; in relation to your route and knowing how far you want to deviate; and a possible point; to return to your course. The information is there; but takes a lot more to put it together. Realizing this will help me put together a big picture plan; even with less information displayed in front of me. I will; in the future; work very hard to make sure that ATC has a shared mental model of what our deviations are and what the overall plan is. And pay special attention when we are handed off that the new Controller knows what the plan is.


Synopsis: Two B737 pilots and a ZDC Controller involved described a failure to communicate the planned weather avoidance route. ATC believed the crew was trying to create a short cut and the crew stated they were merely trying to stay on the upwind side of a large thunderstorm.