00:00As we close out the week here, still about a week before Halloween, we need to keep an eye on
00:05the tropics still.
00:06And there's a new problem developing that's going to bring significant onshore winds to the southeast coast.
00:13So instead of it being the mid-Atlantic, areas like the Chesapeake Bay with the greatest coastal flooding,
00:18we're shifting our attention now to southern South Carolina, central South Carolina even, areas around Charleston,
00:25central parts of the coast all the way down through Georgia and Florida,
00:27because there's a separate area of low pressure that will be a problem.
00:31Whether it becomes an organized system or not, we're going to be tracking that onshore wind
00:38on the north side of a developing area of low pressure.
00:40By the way, we're calling Josephine Tropical Wind and Rainstorm.
00:45Josephine, no longer a true tropical entity.
00:48In fact, there's even a little bit of wet snow on the back northwest side of this storm over land
00:51in the higher ground of the Canadian Maritimes.
00:53That storm's on the way out, and it will be racing across the North Atlantic.
00:58It'll bring some wind and rain to the British Isles next week, most likely.
01:02But look at this, a new area of disturbed weather, big plume of moisture streaking across the Caribbean,
01:09and there's going to be this onshore wind that develops over parts of the southeast coast.
01:15So this new area of low pressure is really what we're focusing on,
01:18and that becomes our new troublemaker here regarding coastal flooding.
01:23As we look at the satellite loop right now, again, there's not a whole lot of organization to this yet.
01:30It's still in its early stages, but as we loop this out,
01:34you can see low-level flow coming in from the northeast, upper-level flow from the southwest,
01:40and we're going to begin to see this spin up into an area of low pressure off the Georgia and
01:46Florida coastline.
01:47Before I get into the modeling, I wanted to show you a graphic that Bernie put together earlier
01:51about how the jet stream and the winds aloft are going to pinch off to the point that
01:55this may even breed a separate zone of low pressure to the south.
02:00That may organize.
02:01We're very confident in this onshore wind tied to the northern plot of that low,
02:06and there are some similarities to what happened with Josephine.
02:09Initially, something that was associated with a jet stream, a temperature contrast at the ground.
02:14Part of the storm was fractured and carried away,
02:17and then this residual low-pressure center sat for a long period of time over warm water,
02:22long enough for it to develop some deep concentrated convection of its own near the center of the storm,
02:27and then subtropical storm Josephine was formed.
02:30We'll be watching this area in the coming days,
02:32and I'll look at the modeling here after one more graphic here
02:37showing the stormy water, that onshore wind Saturday, Sunday, Monday,
02:43leading to coastal flooding, but also some rain in Florida.
02:47All right, I'm going to step away from our graphics.
02:49We're going to go back to them in a little bit and show you the takeaway,
02:51but overall, here you can see as we begin the weekend,
02:56I want to trace the upper-level flow with the southern branch of the jet,
03:01and it is going to fracture.
03:02There's a dip in the jet stream, and the southern branch is going to kind of get so amplified
03:07that eventually we may see this area of low pressure just kind of break off of the jet stream,
03:14and by Sunday night and Monday, a closed area of circulation begins to form.
03:18That's what the European is hinting at.
03:21The NAM kind of doesn't quite amplify things enough.
03:25You can see in the GFS, by Monday evening, we have a closed contour down over the Bahamas,
03:31and then the pinching off of the jet exiting to the northeast.
03:36In the NAM, we don't really see that.
03:38It remains one deep trough that continues to slide east,
03:42and we don't really see that area of low pressure pinch-off quite the same.
03:47And then with the GFS, here the GFS is, it really digs deep,
03:52and it comes really close to fully pinching off here,
03:55but as we move forward then into Monday and Tuesday,
03:59it just takes a little bit longer for that to fully break off.
04:02By Tuesday night and Wednesday, it does break off east of Florida,
04:06and the jet stream aloft, the winds aloft, kind of de-amplify, race away to the northeast,
04:13and we're left with this new area of low pressure that's been deposited to the east of Georgia.
04:18So we'll be watching for possible development there,
04:21and when it comes to the wind shear, again, it's initially fairly strong
04:25because we have this big dip in the jet stream that's ultimately producing this whole pattern,
04:29but if we get to a point when the upper-level winds kind of scoot away,
04:34and you can see that happening here in this depiction of it,
04:39if the strongest winds scoot away by Wednesday,
04:43we're left with an area with weaker winds aloft,
04:46and if there is residual low pressure here off to the east of Florida,
04:50perhaps we could see something organized there in that area of relatively limited shear.
04:56Here's a look at what actually the models are producing
04:59in terms of rainfall and surface pressure forecasts.
05:02The GFS, remember, this was slower to produce that area of low pressure.
05:05There it is, Wednesday, and it's over this area with a little less wind shear.
05:09Remember, the stronger shear is removed from this area,
05:12and it's a weak system, and eventually it gets scooped up to the northeast,
05:15but perhaps there's a small chance that could organize it to a subtropical system.
05:19Here's the Europeans, a little farther south,
05:22and it never really organizes severely,
05:25but there will still be this continual onshore wind,
05:28whether it organizes or not, blowing into the east side of Florida.
05:33So that's going to put us in a spot here where we have multiple days in a row
05:37with this onshore wind,
05:38and if we just take it Saturday, Sunday, Monday, Tuesday over a four-day period,
05:42initially the strongest influence here is up in north Florida, Georgia, and South Carolina,
05:48and then even in the pink zone here, Charleston is in an area that is especially prone
05:54to coastal flooding because of some of the old historical neighborhoods
05:57that sit very low, barely a couple of feet above the sea level,
06:02and we're concerned about coastal flooding there.
06:05So let's take a look at the tide chart here,
06:07the forecast for the next several days
06:10with the water level forecast here in Charleston Harbor.
06:16So here it is, and we're going to be dealing with a high tide
06:19that may match and actually step up into major flooding
06:23by the time we get to Sunday and Monday,
06:25so major flooding Sunday and Monday.
06:28And overall, we're going to categorize the risk of development here
06:31for this as a tropical system or subtropical.
06:34Still low for now.
06:36We do have warm water.
06:39We consider 79 to 80 degrees kind of the minimum threshold.
06:42We're there.
06:43We're warm enough, but there's a lot of wind shear in the short term.
