On 10/27/2005 13:55, wrote:

: : "MVFR means Minimum or Marginal Visual Flight Rules. MVFR criteria means
: a
: : ceiling between 1,000 and 3,000 feet and/or 3 to 5 miles visibility."
:
: : http://www.weather.gov/glossary/glossary.php?letter=m
:
: I stand corrected. The little blue dots on aviationweather.gov always
: seemed
: to go away at 1500'.

: That's a handy web site. Here's a link to the cite's guides to the meaning
: of its symbols and acronyms:
: http://aviationweather.gov/static/info/

As far as the regs go, is "MVFR" even defined? I kinda doubt it... it's
either below minimums (as prescribed by the overly complicated VFR cloud
clearance/visibility rules), or it's not.

Well, it's defined (at least) in the Handbook of Aeronautical Knowledge
(FAA-H-8083-25) and used throughout that document.

From page 10-15, in the section describing the Weather Depiction Chart:

"Areas of IFR conditions (ceilings less than 1,000 feet and
visibility less than 3 miles) are shown by a hatched area
outlined by a smooth line. MVFR regions (ceilings 1,000 to
3,000 feet, visibility 3 to 5 miles) are shown by a non-hatched
area outlined by a smooth line. Areas of VFR (no ceiling or
ceiling greater than 3,000 feet and visibility greater than
5 miles) are not outlined."

It is also defined in Aviation Weather Services, AC-00-45E:

IFR - Ceiling less than 1,000 feet and/or visibility less
than 3 miles; hatched area outlined by a smooth line.

MVFR (Marginal VFR) - Ceiling 1,000 to 3,000 feet inclusive
and/or visibility 3 to 5 miles inclusive; non-hatched area outlined
by a smooth line.

VFR - No ceiling or ceiling greater than 3,000 feet and visibility
greater than 5 miles; not outlined.




In any event, except for mountainous terrain, I wouldn't think twice about
launching VFR into 2700 AGL.

-Cory




--
Mark Hansen, PP-ASEL, Instrument Airplane
Sacramento, CA