(meteorobs) Final Weather Outlook for Tuesday Morning's Transit of Venus

[Skywayinc at aol.com]

This is going to be my final outlook concerning the Tuesday morning weather 
for the Venus transit.  At this hour (2:15 p.m. EDT), visible satellite 
pictures show much of the Northeast US and Ohio Valley under mainly sunny skies.

However . . . looking at the latest 12Z forecast guidance from several 
different models, it appears that just about every location west to the Ohio Valley, 
south to central Virginia and north through New England will have at least 
one and in some cases as many as three things to be concerned about on Tuesday 
morning.

1) The first is the potential for low clouds and fog.  As noted in the 
previous two updates, the lowest levels of the atmosphere -- below 1,500 feet -- 
will have relative humidity levels hovering close to the point where low 
cloudiness and patchy fog could develop in the predawn morning hours.  The projected 
values have again come down from the previous two computer runs, but many 
locales will still be hovering precariously close to the 80% mark -- the level 
which I personally use to indicate the possibility of morning low cloud and fog 
development.  This means that it might be worthwhile staying away from valleys 
and coastal sections where low clouds and morning fog have a history of 
developing. 
    
2) The second is a slight "wrinkle" in the upper atmospheric flow over 
central New England, which could induce some patchy mid-to-high level cloudiness 
over eastern New York State and much of New England.  

These clouds may be especially prevailent over northern sections of Vermont 
and New Hampshire as well as western portions of Maine.  It is possible that -- 
especially in these three regions -- the Sun might appear significantly 
diffused (as if looking at through a jar of mayonaisse).

3) The final thing is the haze, which has rapidly increased over the past 
24-hours in response to a wind shift into the southwest.  It is conceivable that 
in those areas that have a clear view of the rising Sun on Tuesday, the haze 
could significantly attenuate the Sun's light to a degree so that the use of 
dense solar filters might completely hide the Sun.  As the Sun climbs higher 
into the sky, however, the amount of haze it will compete with should gradually 
diminish.

So for as quoting any viewing odds, I would say that for New England, Greater 
New York-New Jersey, Upstate New York, Middle Atlantic Coastal, and the 
eastern sections of the Ohio River Valley, I would say it is in the 40 to 60% 
range.  

Sorry these numbers can't be higher, but I feel that there are just too many 
factors out there that loan itself against being able to go with a higher 
probability of good weather; I really can't point to any one specific region and 
say, "There!, that's where you're definitely going to find clear skies on 
Tuesday morning."  

I would simply check the sky frequently, especially during the second half of 
the night (look for the almost-last quarter Moon).  Hopefully, the sky will 
still be reasonably good by dawn.  If not, you might want to do some 
last-minute traveling.  In this kind of weather set-up, a clearer sky might not be too 
far away.

Good Luck to All!
-- joe rao
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