Narrative:

Solid echo line extending slightly west of ZZZ to east of ZZZ1 and ZZZ2 with tops above FL410 and one reported possible top at around FL700. On board radar showed very few areas with any possibilities of deviation and rapidly closing those gaps. Dispatcher had warned me of rapid developing saturation of previously opened gaps. Safety of flight required the use of captain's emergency authority. After cleared of the weather ATC cleared us direct ZZZ3. Dispatcher informed us of possibility of another severe weather approaching the ZZZ4 field. ZZZ approach gave us instructions to hold on the zzzzz X arrival at the zzzzz fix as published with a 30 minutes delay. Weather over the field was slow in moving. Dispatcher informed us of ZZZ5; ZZZ6; and ZZZ7 as alternates and we chose ZZZ7 the closest; hardly any weather and it had customs available since we were an international flight; which required ice. Description: severe weather deviation. Breaks in between echo line closed in rapidly leaving no place to cross safely; and ATC informed that to avoid weather I had to go as far west as ZZZ. Informed ATC that's where we needed to go and gave them an initial heading of 310. Winds aloft required a heading of 290. Switched frequencies and next sector wanted me to turn right back on course direct to ZZZ VOR and proceed on course as previously filed within the next 20 miles. Military restricted area was active and unless I exercised emergency authority he could not let me deviate through the active area. I squawked 7700 and proceeded to deviate.

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Original NASA ASRS Text

Title: An air carrier crew declared an emergency and deviated from the cleared routing in order to avoid weather after ATC was unable to grant the requested weather avoidance track deviation.

Narrative: Solid echo line extending slightly west of ZZZ to east of ZZZ1 and ZZZ2 with tops above FL410 and one reported possible top at around FL700. On board radar showed very few areas with any possibilities of deviation and rapidly closing those gaps. Dispatcher had warned me of rapid developing saturation of previously opened gaps. Safety of flight required the use of Captain's emergency authority. After cleared of the weather ATC cleared us direct ZZZ3. Dispatcher informed us of possibility of another severe weather approaching the ZZZ4 field. ZZZ Approach gave us instructions to hold on the ZZZZZ X arrival at the ZZZZZ fix as published with a 30 minutes delay. Weather over the field was slow in moving. Dispatcher informed us of ZZZ5; ZZZ6; and ZZZ7 as alternates and we chose ZZZ7 the closest; hardly any weather and it had customs available since we were an International flight; which required ICE. Description: Severe weather deviation. Breaks in between Echo line closed in rapidly leaving no place to cross safely; and ATC informed that to avoid weather I had to go as far west as ZZZ. Informed ATC that's where we needed to go and gave them an initial heading of 310. Winds aloft required a heading of 290. Switched frequencies and next sector wanted me to turn right back on course direct to ZZZ VOR and proceed on course as previously filed within the next 20 miles. Military restricted area was active and unless I exercised emergency authority he could not let me deviate through the active area. I squawked 7700 and proceeded to deviate.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.