Two powerful warm-core cyclones 10,000 km apart

This afternoon we had the treat of having two warm-core cyclones with (estimated) sea level pressures less than 915 hPa: Supertyphoon Juan/Megi (15W... different names from Philippines & JTWC), which saw a research aircraft dropsonde SLP of 893 mb and max winds of ~165 kts, and a polar low approaching the Drake Passage, which was analyzed by the 18Z GFS to have SLP of ~912 hPa. (On a side note, anyone know how the GFS gets this analysis? I can understanding the routine analyses of 1000 mb, heck even the rarer 970 mb low... but a 912 mb low? Is there a +/- involved... perhaps as much as 15 mb? Just thinking...)

Here are a few images.