Figure 1 – Image courtesy of NOAA & Wikipedia
With the 30th anniversary of the ‘great’ storm of October 1987 now just a few days away, I thought it was about time that I looked into the rumours that ex-hurricane Floyd had something to do with it. After looking at some surface pressure charts for the Atlantic from the 12th to the 15th , I can now see how this speculation came about, and also better understand that Floyd was the hurricane that Michael Fish was referring to in his now infamous forecast when he said:
“Earlier on today, apparently, a woman rang the BBC and said she heard there was a hurricane on the way… well, if you’re watching, don’t worry, there isn’t!”
In the prologue to the book ‘Storm Force‘ which he co-authored, Michael Fish does explain that he was talking about hurricane Floyd and:
“…my remark had NOTHING to do with the storm”
He goes on to add that the infamous forecast:
“…was NOT made the evening before and NO woman rang the BBC”
Looking at the video on YouTube of the now infamous forecast, it’s not entirely clear to me at what time it was broadcast. It could have been from late the evening before (14th), but it seems more likely it was the broadcast after the midday news on the 15th, because rolling 24 hour news from the BBC started much later than 1987 as far as I remember. Michael Fish reminds us in his prologue is at pains to explain that it was Bill Giles who was the duty forecaster that evening (15th), and it was he who uttered the immortal line:
“…it will be a bit breezy up the channel”
As Michael Fish reminds us:
He kept quiet about this until he had collected his OBE and retired!
The culprit as we know was not any of the messengers, but a combination of poor guidance from Bracknell, poor forecast from what now looks a rather crude and unsophisticated NWP model, which itself was due in no small part to a dearth of ship observations from Biscay during the afternoon. Anyway I digress, as I so often do these days, so back to the main point of this blog.
Is there any truth in that speculation, that the October storm was the remains of ex-hurricane Floyd?
Figure 2 – Data courtesy of the NHC
Floyd had just slipped past the southern tip of Florida as a hurricane on the 13th of October 1987, here’s the reanalysis chart for 00 UTC (fig 3).
Figure 3 – Data courtesy of NCEP/NOAA reanalysis
The chart below (fig 4) shows the last position listed in the Hurdat2 archive for ex-hurricane Floyd, and this is how Wikipedia described the demise of Floyd.
Unexpectedly the storm turned sharply northeastward into the southeastern Gulf of Mexico. Based on reports from the Hurricane Hunters, Floyd briefly attained hurricane status on October 12. Around the same time, the nearby cold front spawned a low pressure area that cut off the hurricane’s inflow. While moving through the Florida Keys, Floyd became the only hurricane to affect the United States that year. However, its convection was rapidly decreasing over the center due to the front, and shortly thereafter Floyd weakened to tropical storm status. The circulation became nearly impossible to track on satellite imagery, although surface observations indicated it passed just south of Miami, Florida. The storm underwent extratropical transition as it weakened over the Bahamas, and Floyd was no longer a tropical cyclone by late on October 18*. The circulation dissipated within the cold front early the next day.
Figure 4 – Data courtesy of NCEP/NOAA reanalysis
And below (fig 4) is the position of the embryonic low that became the ‘great storm’ at 00 UTC on Thursday the 15th of October. I’ve measured the approximate distance between the last observed position of ex-hurricane Floyd and the first of the October storm, and its a whopping 2,600 nautical miles, and even if it had been doing over a hundred knots as a surface feature, Floyd just couldn’t have made it. Perhaps at the middle and upper levels if there had been a jet that spanned the Atlantic from the Bahamas to western France which was blowing at 240° and 100 knots, tropical air from Floyd could have been pulled eastward to fuel developments in mid Atlantic. I’m no expert, but I suppose it’s possible that tropical air somehow got entrained into a developing extratropical low, Floyd did rather mysteriously turn to the northeast and lose intensity as the Wikipedia article points out, but I would have to download more reanalysis wind data for 500 hPa and above to check if that could have been the cause, there’s nothing quite like a good conspiracy theory is there?
Figure 5 – Data courtesy of NCEP/NOAA reanalysis
As we now know the rest is history (fig 5) even though the coarse grid of the NCEP reanalysis doesn’t quite get the intensity of the October storm.
Figure 6 – Data courtesy of NCEP/NOAA reanalysis
*This slip may be intentional or not, but I reckon that 18 should be a 14 according to the NHC record.