OK, Hi everybody, David Paul with you in
the KHOU 11 Weather Center this is Wednesday
evening as I give you your Atlantic
tropical update here on September 22nd.
It is also the autumnal equinox.
It is the day where the northern hemisphere
in the southern hemisphere at the same
amount of daylight and nighttime after today.
Days begin to get shorter nights longer
in the northern hemisphere is the earth
slowly tilts away from direct sunlight
and we plunge headlong into a long.
Winter. Atlantic Basin,
so we've been busy 1415 sixteen 17
named storms so far this season and
it looks very likely that within the
next day we're going to get another
system named here that would be Sam.
So that would put us at 18 named systems for
the season to remind you and normal season.
The 30 year averages 14 storms.
So we've had 17.
We're going to have 18 here in
the next literally moments is,
I think, TD 18 is going to turn into
Sam pretty quickly.
Normal amount of hurricanes is 7.
We've had six so far.
We're likely to make it seven with Sam.
In fact,
Sam is likely to become a major hurricane,
and if it does,
that would mean for the season we would
have a total of four major hurricanes,
cat three or above.
Normal is 3,
so we're getting ahead of average
along as long as Sam does what we
think it's going to do as we head
into the second half of the season,
we've still got about 40% of the season left,
and we're already at well ahead
of a normal season.
So this is again turning out
to be a busy one.
We may run out of names on our first listen
then instead of going to the Greek alphabet,
there's a secondary list of
names that we would begin to use.
Here's the way the Atlantic
Basin looks this evening,
and still this spot up here.
North Atlantic 40 to 60% chance
for development and again
still on the back burner.
This one just looks like
whatever is going to form here.
Just going to kind of sit here and then
eventually just meander and fall apart.
I don't think this is going to impact St.
Johns Newfoundland,
Halifax in Nova Scotia.
I think y'all are fine from that.
Peter is fizzling roses fizzling
it's TD18 that is cranking and about
to become a named tropical storm.
And I think eventually a hurricane
and look it is forecast to become
a major cat three hurricane here
over the next five days.
We'll start with Peter.
And again, just completely ripped apart.
Peter is not much longer for this Earth.
You can see it's an exposed center
as we look at the visible satellite
from the day we're going into night
time now in the Atlantic Basin,
so that's why it fades to black.
But during the daylight hours
you could clearly see an
exposed and now kind of ragged center,
all the convection being torn off to the
north and east by the upper level winds.
So this is what we talked
about with wind shear.
Look at the upper level winds just
cutting right across it, ripping.
The system apart decapitating it,
if you will, that's a system that's
going to weaken in a hurry and it has
now just a depression and turning
into a remnant low here over the
next several hours and moving north
and then fizzling out by Friday.
And also if you've been following along
earlier in the week it looked like
we might see at least a depression
or a weak tropical storm impact.
Bermuda now that looks very unlikely.
So Bermuda.
This system is just dying before it can
give you any type of significant impact.
Maybe some increased seas from the South.
Big picture.
And it's out here off the coast
of Africa Center the Atlantic.
Now that we've got a couple of systems,
rose is fading.
TD18 really has got that look
like it's about ready to become a
named tropical Storm or hurricane.
It's tumbling nicely,
will begin with tropical depression rose,
and it's another one of those
situations where not only of the upper
level winds just ripped it apart,
but if you remember, as we track rose,
it was developing within an area
a cloud of Sahara and dust.
That's the the light sandy color here.
These are surface streamlines.
And so that dust is sinking air.
It's dry air.
Those are the two exactly opposite things.
You need to get a tropical system going.
You need rising air.
You need moist air and so the Sahara
and air layer has snuffed out rose good.
Will say goodbye to Rose and his rose.
Turns east as a remnant low.
I did look at the longer range models.
This does not look like it's
going to impact Portugal,
Spain,
France with any type of significant
low at all.
It just kind of fizzles out and is
absorbed by the atmosphere.
So that really leaves TD 18 to be
the only real player in town.
It is looking more healthy.
We've got a nice little
counterclockwise picture to the
upper and mid level flow around that.
We've got thunderstorms near the
center of the tropical depression,
so again,
a depression means that now we've
got an actual closed 360 degree
closed surface area of rotation.
That's good for helping us
forecast where it's going to go.
But of course it also means
the storm is intensifying.
Now we have a center of low pressure
that the models can grab onto.
This is forecast to become a major
hurricane Cat 3 pretty quickly
in the next couple of days,
so why would that happen?
Well,
it's going to be moving into
an unshared environment.
Rose and Peter were sheared apart,
but this is what an unshared
environment looks like.
Now.
Here's the developing system
and you can see there
is wind flow coming across
the storm from the east,
but the storm was also moving to the east,
so for the moment it's moving along or
the environmental flow, so that reduces.
That easterly shear across the storm
it's moving along with that share,
so it's not really shared at all.
Sort of like floating along with the stream.
And as we zoom out and look out
at the atmosphere that this storm
will be moving into boy, that is a.
Very UN sheared environment light winds.
So for example, where is the sheer?
Well, here's the shear right in here.
So if we had these brighter colored
arrows cutting across right here,
I would say there's no way this is
going to become a major hurricane.
It'll be ripped apart,
but that's not the case.
We have just about 0 shear in here,
so this is going to be a storm that has
a good chance to very rapidly intensify,
not so much warm water,
but upper level winds are the biggest
factor in whether a storm is going to
quickly intensify or weaken rapidly.
It's. Always the upper level wins.
And those light winds indicate
this thing is going to crank.
So GFS and euro.
We looked at this last night and
if you remember you were with us.
This did look like it was
going to create a very tight,
well organized low pressure area.
Both the American and the European
and those two models continue to
agree that we're going to get a
significant area of low pressure.
The models are in very good agreement here.
Moving. Very close to EU S Virgin
Islands or just a little bit further
to the east of the Virgin Islands.
So San Juan Lesser Antilles,
Virgin Islands,
watching this forecast very carefully,
you're going to see a tremendous amount
of high seas come into the area here.
However.
It looks like we might avoid a
direct hit from some of the Northeast
islands here of the Caribbean.
At this point, the storm is moving.
Northwest,
there's a northerly component
to its westerly movement.
So that's encouraging.
We don't want this to hit any of the
islands here and impact the people here.
And that's you know that would be
several 100 miles to the northeast.
If that forecast for the euro holds and
even further away if the GFS holds.
Spaghetti plots are a little more encouraging
that what there is of this will be,
at least in the process of turning to
the north as it approaches the islands.
Here the island chain.
And it's just looking at this.
We've kind of got three clusters.
There's a very small one that's
on a more southerly track.
I think that's more of an outlier.
We've got a cluster here that
takes it close to the Virgin
Islands and then another cluster,
and this is the more there's more
model runs here than any others.
These are all the computer model, the.
Tropical hurricane models
and the arms of the GFS.
And so there's a significant
cluster that keeps it further out
to sea and turns it more northerly,
quicker than some of the other model runs do,
so we're kind of hoping that that plays out.
We don't want this to impact the people here.
And put them through more trauma.
So here's the forecast track
from the Hurricane Center.
They develop it rapidly.
45 on our tropical storm
tomorrow 250 mile an hour.
That's a cat three hurricane.
Sitting east of the Lesser Antilles by
several 100 miles as we go into Monday.
So still,
there's plenty of time to watch this,
but it's encouraging to see that
more northerly component to
its overall westerly movement.
Maybe it will miss the islands.
So where does it go from here?
Overlay the upper level
winds winds at 34,000 feet,
so this was going into Tuesday afternoon.
So here's the forecast.
The storm's position Monday afternoon.
It continues on that track,
puts it here Tuesday afternoon
and look at the Trophee.
So that should tell the story of
where this is going to end up going.
That trough that deep of a trough
should pick it up and eventually
turn it to the north and.
Stop this from having any significant
direct impacts to the East Coast of the
US and even the Bahamas, so Bahamas,
we're keeping a close eye on you guys.
This looks like a setup that would
keep it away from the Bahamas,
away from Florida and away
from the East Coast.
In fact, maybe well away.
Good.
That's the beauty of heading into fall is a.
Quite often you'll start getting these much
more amplified troughs at the upper levels,
and that will grab and turn the storm.
So this is going into Thursday of next week,
so this is.
Eight days out and if you look
carefully you can see right here
there's a little reflection of
where this particular model run.
Things that.
Hurricane might be missing the
islands by a significant amount,
and continuing on that more northerly
track and eventually pulled north
by the upper level winds and on this
type of this type of wind set up.
It would also stay away from.
Halifax and seat in Saint Johns now.
Here's Bermuda.
So Bermuda,
you may end up with a close call from Sam.
We'll have to see how that plays out,
but that could that could turn
it before it actually impacts
even the island of Bermuda.
So that type of a track,
I think is the most likely outcome right now.
Not set in stone, or the most likely,
and that protects the Caribbean islands,
the Bahamas, Florida and the
East Coast from Sam.
That would be a good outcome.
At the same time, more troughs are coming,
continental United States.
So this is next Thursday.
Again, this is 8 days out.
Here's the troft.
That's hopefully protecting us from Sam.
Here's our next trough and this
one is interesting because we're
in fall is also our second severe
weather season across North America.
Canada and the United States
and this truck has my attention
because look how sharp it is.
So this would be a severe weather threat,
perhaps across.
The Mississippi Valley may be just a
little West of the Mid Mississippi
Valley going into next Thursday,
8 days out and then watch what
happens with this jetstream pattern.
So that's concerning.
You see how this jet?
Curlicues back around on itself.
Again,
these are winds at 34,000 feet when
they when they back back around on
themselves and curly Q back on themselves.
Quite often it will create a vacuum
at the top of the atmosphere at
34,000 feet right where those
winds are currently queuing
bending back upon themselves.
And so this would be a severe
weather setup for Wisconsin,
Minnesota, the UP of Michigan,
Northern Illinois, Chicago.
And so this is something we'll
be watching carefully now.
This is 9 days out,
so this is a long range forecast.
But just a heads up,
this is our second severe weather
season across the Great Plains across
the southern plains of Canada as well.
And so heads up thunderstorms could
be quite strong late next week as
we watch that jet stream make it son
Ulations as we move into fall and
look another troughs setting up as we
move it at the same down to the West Coast.
So the troughs are coming.
These also helped to inject
cold air down into the lower 48.
OK,
there's where we stand this
evening on the 22nd.
Only autumnal equinox questions
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We'll see you tomorrow with
another complete update.