Final report from landfall:

(I'm just quoting stuff from the 5am discussion)

Wind:
* A PEAK FLIGHT-LEVEL WIND OF 165 KT WAS MEASURED JUST NORTH OF THE EYE.
* MAXIMUM SURFACE WINDS FROM THE SFMR WERE 124 KT...BUT IT IS HIGHLY LIKELY THAT THE MAXIMUM SURFACE WIND SPEED WAS NOT REPORTED BY THE SFMR INSTRUMENT.
* A GPS DROPSONDE IN THE NORTHERN EYEWALL MEASURED A WIND SPEED OF 178 KT AVERAGED OVER THE LOWEST 150 METERS OF THE SOUNDING.

BASED ON THE DROPSONDE AND THE FLIGHT-LEVEL WINDS...THE INTENSITY IS SET AT 145 KT.

Presure
A DROPSONDE IN THE EYE MEASURED A CENTRAL PRESSURE OF 906 MB JUST PRIOR TO LANDFALL.

SOME HISTORIC NOTES ARE IN ORDER HERE.
* THE 906 MB CENTRAL PRESSURE IS THE NINTH LOWEST ON RECORD FOR AN ATLANTIC BASIN HURRICANE...
* AND THE THIRD LOWEST AT LANDFALL BEHIND THE 1935 LABOR DAY HURRICANE IN THE FLORIDA KEYS AND HURRICANE GILBERT OF
1988 IN CANCUN MEXICO.
* DEAN IS ALSO THE FIRST CATEGORY FIVE HURRICANE TO MAKE LANDFALL IN THE ATLANTIC BASIN SINCE ANDREW OF 1992.

Also, the last recon reported (08:14:00Z):
"CONTINUOUS LIGHTING AND SEVERE TURBULENCE SOUTH EYEWALL"

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Wind: If 178kt was measured, even with a 10% step down (and at 150 feet, 10% may be too large), that is 160kts (184mph), or 15kts faster than the surface value they used.

The 145kt value works out to 165mph.