This interesting paragraph from the official NHC discussion about Humberto:
BASED ON OPERATIONAL ESTIMATES…HUMBERTO STRENGTHENED FROM A 30 KT
DEPRESSION AT 15Z YESTERDAY TO A 75 KT HURRICANE AT 09Z THIS
MORNING…AN INCREASE OF 45 KT IN 18 HOURS. TO PUT THIS
DEVELOPMENT IN PERSPECTIVE…NO TROPICAL CYCLONE IN THE HISTORICAL
RECORD HAS EVER REACHED THIS INTENSITY AT A FASTER RATE NEAR
LANDFALL. IT WOULD BE NICE TO KNOW…SOMEDAY…WHY THIS HAPPENED.