Weather Chat Megathread

[tater]

Least storm surge isn't an issue. What do they say... run from the water, hide from the wind?

[ZooNamedGames]

2 minutes ago, tater said:

Least storm surge isn't an issue. What do they say... run from the water, hide from the wind?

Being up on a hill helps us only slightly. Trees may be the death of us.

[tater]

I'll keep my digits crossed for ya (all of them).

[ZooNamedGames]

1 minute ago, tater said:

I'll keep my digits crossed for ya (all of them).

Thanks. Myself and many others (I can think of two on this forum who) need it.

[ProtoJeb21]

I've decided to check the newest models on Ventusky and Tropical Tidbits. The latter I only just decided to check because it accurately predicted Harvey's peak intensity and rain almost a WEEK in advance. It also suggests that Hurricane Irma could become the second-strongest hurricane in the Atlantic, with a pressure of 886 mbar, and also says it could make a South Carolina landfall on 9/11 as an 890 mbar storm.

Ventusky is in agreement with most other models, saying that Irma will make a sharp northward turn into the side of Florida or the Carolinas. It also says that it could make landfall on one of the islands of the Bahamas on September 9th while intensifying into a more powerful Category 5. This is also when Tropical Tidbits says Irma will reach record-low pressures. After that it will travel up Florida's east coast as a 180 mph to 190 mph hurricane before making landfall. Ventusky still suggest that Jose could get near or acquire Category 5 intensity by the 13th or 14th.

Tropical Tidbits suggests that Katia could also become a hurricane, reaching its initial lowest pressure of 986 mbar by the 9th. After slightly weakening, it will make landfall at 981 mbar. Tropical Tidbits also says that while Irma will not get as powerful as originally suggested, it could reach incredibly low pressures of around 890 mbar.

[Green Baron]

Ventusky & co are just websites that use data from the national weather services and present them in a more or less convenient way mixed with ads and tracking software, or, to put it more courteous, they focus on "data visualisation". There is nothing special about it, they don't run supercomputers and don't do own research.

They may be "right" today and "wrong" tomorrow. I've seen that several times over the past 15 years.

The by far best sources are indeed the weather offices, and in front (probably together with others, idk) the American NOAA and German DWD because the can afford the biggest computers and have the best educated (and paid) folks and their own developed global, regional and local weather models. They are regularly involved in publications and research.

The officials hold themselves back as to any words that exceed the model's forecast range (usually less than 8 days, but depends on synopsis as well as local or regional things, the subject or statistical confidence). That's why you'll never hear something like "in 10 days people will drown on the Bahamas" because they know by experience that this may be or may not be.

The "data presentation" sites are less contained, they predict happy over the model's limits and sometimes it happens to fit right in, sometimes not. They have no reputation to loose, shut down and open anew the other day under a different name.

Just sayin', to sharpen the senses :-)

Edited September 6, 2017 by Green Baron

[tater]

[Green Baron]

Morning (well, already after lunch here) :-)

How are things on the Windwards Leeward Islands of course tststs ?

Edited September 6, 2017 by Green Baron

[tater]

 

 

[Green Baron]

Outch ...

[ProtoJeb21]

19 minutes ago, Green Baron said:

Morning (well, already after lunch here) :-)

How are things on the Windwards Leeward Islands of course tststs ?

 

5 minutes ago, tater said:

 

 

Well...snap. That is absolutely catastrophic. Pray that this thing stays well away from Haiti, or else Irma will end up as an even WORSE disaster.

[DarkOwl57]

This is bad.... Stay safe Florida! If the images are anything to go off of, Irma is going to be devastating.....

[ProtoJeb21]

UPDATE: The thirteenth NOAA recon mission into Irma has just left from one of the Bahamas. Expect intensity updates within the next hour or two.

[The Space Dino]

8 minutes ago, ProtoJeb21 said:

 

Well...snap. That is absolutely catastrophic. Pray that this thing stays well away from Haiti, or else Irma will end up as an even WORSE disaster.

Yeah, poor Haiti is wrecked enough in the past already...

[ProtoJeb21]

NOAA Recon mission 13 has just entered the outer end of Hurricane Irma!

[tater]

 

 

 

Strongest in the open Atlantic... a few meteoroligists I have seen are annoyed, since it's tied with a few other storms over a broader region of the Atlantic.

[tater]

NHC shifts again:

Another shift East would be awesome. I assume that the farther north it gets, the more chance to lose strength. Also, slamming into the Carolinas is bad, but there are actually terrains there that can kill this beast, unlike FL, which is dead flat.

[ProtoJeb21]

Three NOAA planes are out now. The first was the 13th Irma recon flight, which is now exiting the hurricane after flying straight through the eye. The second is a training mission in the Gulf, and the third is another recon - this time into TS Katia. I'm quite confident that its forecasted track will be updated for a potential hurricane-strength landfall in Mexico.

[Mr. Quark]

On 7/17/2016 at 8:19 PM, ProtoJeb21 said:

How weird, crazy, or dangerous has your weather gotten? Is there a weather event you would like to share? Have you ever experienced a blizzard, tornado, or hurricane? Here are a few I would like to share:

 

 

Several thunderstorms have randomly dissipated right before hitting where I live. Strange...

Seems like Texas. Same for me, I live near Fort Worth.

[tater]

Last night I saw an awesome gif of the whole Atlantic water vapor (loop). Tried to get it at NOAA, but they are hammered, it was slow.

It was false color, obviously, but it looked like Jupiter. Really showed the way tropical storms swirl along the equator (Irma and José in particular). BTW, what is with people not being able to type José properly in news stories?

[Green Baron]

Thunderstorms, if they form because of insolation (isolated ones usually do, in contrast to cold fronts where cold air destabilises the troposphere in a line) can fall apart when they form too early in the day. The morning sun destabilises by heating the ground layer, the ground layer shoots up, clouds form, maybe a shower or even thundershower but then the shadow blocks the sun from further heating the ground. If no other means of labilisation exist (cold air at altitude, warm/moist at lower levels) then the shower dissipates.

In the afternoon or evening, when the sun is low, it can shine under cloud, keeping the fire going, thus feeding longer lasting thunderstorms that drift with the overall wind and can keep going until the early morning.

This is, of course, a generalisation ....

[DarkOwl57]

52 minutes ago, tater said:

[pic snipped for space saving]

Another shift East would be awesome. I assume that the farther north it gets, the more chance to lose strength. Also, slamming into the Carolinas is bad, but there are actually terrains there that can kill this beast, unlike FL, which is dead flat.

Agreed; Carolinas north would be bad (The megalopolis (s) of NYC, Penn, NJ, etc.). However, I think the best thing (Don't quote me wrong here) would be for the hurricane to hit an area that's prepared for it. (I'm gonna draw so much flak for this.) Florida is a state that gets continuously pummeled by Hurricanes. But they're ready for it. It would be waaaaay worse for a Hurricane to hit an area that's not prepared for a storm of this magnitude then an area that has prepared. I think this is kinda a battle os the lesser of two evils. Either hit an area that isn't all that ready for it that'll most likely kill it, or hit an area that is prepared but without a way to destroy it.

[ZooNamedGames]

[Ignore this]

Edited September 6, 2017 by ZooNamedGames

[tater]

1 hour ago, Green Baron said:

Thunderstorms, if they form because of insolation (isolated ones usually do, in contrast to cold fronts where cold air destabilises the troposphere in a line) can fall apart when they form too early in the day. The morning sun destabilises by heating the ground layer, the ground layer shoots up, clouds form, maybe a shower or even thundershower but then the shadow blocks the sun from further heating the ground. If no other means of labilisation exist (cold air at altitude, warm/moist at lower levels) then the shower dissipates.

In the afternoon or evening, when the sun is low, it can shine under cloud, keeping the fire going, thus feeding longer lasting thunderstorms that drift with the overall wind and can keep going until the early morning.

This is, of course, a generalisation ....

These are the typical thunderstorms we get in New Mexico during monsoon season (which is right now). Isolated cells form, typically in the afternoon, and rain out as them move, particularly in areas of orographic uplift (i.e.: on my house).

One interesting thing I got to see was such nascent storms (clouds starting to tower, but not yet thunderstorms) evaporating during an annular eclipse. The buddy I watched it with is a lightning physicist, so he made sure we paid attention.

[Green Baron]

A shadow can destabilize as well.

Classic example: if the sun has shone e.g. on a cornfield for several hours then there is a lot of warm air between the blades (not sure if they are called so, the stems of grass ?). You surely know the effect from a summer afternoon when hiking through the fields, before they are mowed. A shadow (like from a cloud or the said eclipse) passing over it cools the overlying air and so immediately opens the way for the hot ground air to rise, a gust goes over the field, sometimes strong enough to form a little dust devil. If the rising package of air reaches a height where it condensates it can build these towers. On a hot dry afternoon these thermal clouds sometimes start to rain, one can see the veil but the rain doesn't reach the ground.

A shower/thunderstorm passing over land partly feeds itself by ingesting warm ground air in front of it, air that it has itself labilised, thus lasting long through the night even when the sun has long gone.

Generally spoken, of course :-)

Edited September 6, 2017 by Green Baron