THE MODELS ARE NOW IN EXCELLENT AGREEMENT WITH ISABEL MAKING LANDFALL ALONG THE CENTRAL U.S. EAST COAST IN ABOUT 4 DAYS. THERE IS STILL UNCERTAINTY ON WHERE THE EXACT LANDFALL COULD OCCUR SINCE THE DEVELOPING CENTRAL U.S. TROUGH COULD DEEPEN AND DIG SOUTHWARD MORE THAN IS FORECAST BY THE GLOBAL MODELS...WHICH COULD LEAD A MORE NORTHWARD MOTION AND LANDFALL FARTHER UP THE EAST COAST THAN WHAT IS CURRENTLY FORECAST. UNFORTUNATELY...ALL OF THE MODEL GUIDANCE AGREE ON A LARGE AND STRONG NORTH-SOUTH ORIENTED RIDGE REMAINING EAST OF ISABEL...WHICH SHOULD PREVENT THE POWERFUL HURRICANE FROM RECURVING OUT TO SEA. LANDFALL ALONG THE U.S MID-ATLANTIC COAST SOMEWHERE BETWEEN NORTH CAROLINA AND NEW JERSEY BETWEEN 4 OR 5 DAYS IS APPEARING MORE AND MORE LIKELY.
ONLY MINOR FLUCTUATIONS IN INTENSITY ARE EXPECTED FOR THE NEXT 3 DAYS AS ISABEL IS FORECAST TO MOVE OVER SIGHTLY WARMER WATER AND REMAIN IN A FAVORABLE DOUBLE-OUTFLOW PATTERN. HOWEVER...BY 96 HOURS...ISABEL IS EXPECTED TO BE ACCELERATING NORTH-NORTHWESTWARD UNDER INCREASING SOUTHERLY UPPER-LEVEL FLOW. HOWEVER...ALL OF THE MODELS ARE IN GOOD AGREEMENT ON THE CENTRAL CORE OF ISABEL REMAINING EAST OF THE STRONG JETSTREAM AND UNDER 20-25 KT 200 MB WIND. THIS WOULD TEND TO KEEP ISABEL STRONGER THAN WHAT THE SHIPS INTENSITY MODEL IS INDICATING...ESPECIALLY SINCE ISABEL WILL BE MOVING OVER THE WARM GULFSTREAM SOUTH OF THE NORTH CAROLINA OUTER BANKS AT THAT TIME. THEREFORE...LITTLE OR NO SIGNIFICANT WEAKENING IS EXPECTED TO OCCUR UNTIL AFTER LANDFALL OCCURS.
I don't know if an open chimney in a hurricane is such a good idea. Better to check out that sterno stove.
I will tell him "bug out".CNN showed a posible direct hit to Ocean City.We have only had this place for 10 months.This can't be happening.
My county (Boone), and corresponding counties get hit pretty hard when the heavy rains come. With shallow streams that are often clogged, along with runoff from strip mines really screws with us.
I live on a mountain, which is a good thing, but most of my neighbors are not so fortunate.
stay tuned, there are many factors affecting the track. you can see from some of the quoted meterological commentaries that the path is a battle between this trough over the central US and the westward extension of a high pressure system over bermuda. so its an evolving tug of war. in the last update, there was clearly more of a extension of the westward movement and a general speedup, which means the trough is less likely to get it which moves the onshore strike point to the south.
That's what we are worried about here as well. I have friends that live on the Patapsco in Historic Ellicott City. If a storm like this comes through there it will flood EC again like it has in the past- downtown will be devastated. With all the rain lately the water levels down there are already high. I've seen pictures of what Agnes did to that area. Not pretty.
Issued at: 10:26 PM AST 9/14/03 (gateway).
Intense isabel continues heading west-northwestward,
At 11 pm ast, 0300z, the center of hurricane isabel was located near latitude 24.5 north, longitude 68.3 west or about 85o miles 1370 km, south-southeast of cape hatteras north carolina. This position is also about 535 miles, 860 km, east of nassau in the bahamas.
Isabel is moving toward the west-northwest near 13 mph, 20 km/hr and a gradual turn toward the northwest is expected during the next day or so.
Maximum sustained winds are near 155 mph, 250 km/hr, with higher gusts. Little change in strength is forecast during the next 24 hours.
Hurricane force winds extend outward up to 115 miles, 185 km, from the center, and tropical storm force winds extend outward up to 205 miles, 335 km.
The estimated minimum central pressure is 933 mb, 27.55 inches.
Large ocean swells and dangerous surf conditions are likely over portions of the greater and lesser antilles, the turks and caicos islands, and the islands of the bahamas over the next few days. These dangerous surf conditions will also affect portions of the southeastern u.s. Coast during the next several days.
Repeating the 11 pm ast position, 24.5 n, 68.3 w. Movement toward, west-northwest near 13 mph. Maximum sustained winds, 155 mph. Minimum central pressure, 933 mb.
The next advisory will be issued by the national hurricane center at 5 am ast.
Just now heard on the news that Isabel will hit between NC & NJ. It's not going to hit South Florida....nor North Florida.
Tropical Weather Discussion
by Gary Gray
http://www.millenniumweather.com/tropical/discuss.html ...Isabel Prepared To Threaten The East Coast [9/14 5PM EDT]...
As I begin writing this some of the latest (12Z Sunday) model guidance is still just flowing in. So, here in the intro (that data will be in by the time I get to the model section below) I cannot guarantee model agreement. However, based on the model data presently awailable, there continues to be astounding agreement... in fact, even more so that we saw yesterday. Though the 12Z GFS has shifted a bit north, while the 12Z NOGAPS has shifted a bit south, those shifts have been fairly miniscule. The GEM and GFDL, however, have shifted dramatically southward. The GEM held its ground until 00Z, keeping a Long Island/New England threat. But, at 12Z it abandoned ship a sent Isabel blasting ashore in the Delmarva. The GFDL 24 hours ago had been poised to bring Isabel into New York City. Each run since has drifted a bit further west. The latest, 12Z, run... just in as I begin this... now has landfall near Wallops Island, VA... also on the Delmarva. Barring any surprises from the last remaining models to come in, all major models have landfall between about Morehead City, NC (the NOGAPS may be a shade south of there) and the NJ side of the Delaware Bay. They have landfall in about four to four and a half days (in other words, late Thursday).
While this risk area from the various models remains a fairly sizeable chunk of real estate, it is actually a very small range of options for a four day forecast. Moreover, enough northward component of motion, forward speed, and assistance in the pressure gradient from the high to the north is all present even in the westernmost NOGAPS to send a considerable amount of nasty weather well up through the Mid-Atlantic (except the far NE). Meanwhile, the northernmost models are now far enough south so that they plow Isabel through the heart of the Mid-Atlantic. In other words, regardless of which model solution one believes, the Mid-Atlantic will take a hit later this week. The only alternative is if you do not believe any of the models. As you'll see below, in my opinion, this is not the case... I believe the models are on target. Of course, with the severest of weather confined to the eyewall and a short distance on the north side, the precise landfall location IS critical for determining where the truly severe conditions will occur. So, I don't mean to make it sound as though the precise course of Isabel is irrelevant. Far from it. Rather, since there is absolutely no way we can yet determine the precise final course with certainty, I just think it's important for Mid-Atlantic residents to be aware that ALL model guidance brings some harsh weather for MOST of the Mid-Atlantic.
At any rate, with that heads-up to the Mid-Atlantic thrown out there, let's get to the meat of the discussion...
Current Conditions: Though more recon data will be available before I complete this discussion, and by the time I've completed this post and distributed, you'll likely already be aware of this, but... The most recent recon data (as of about 18Z Sunday) indicates that the seemingly standard overnight weakening that Isabel has been going through is, once again, stalled and reversed. After a recon pressure measurement early this morning as high as 940mb, the second and final pass for that recon measure 938mb... possibly indicating the end to the weakening trend. Indeed, this 18Z report has measured a central pressure of 933mb and a maximum flight level wind, so far, of 150kts... which corresponds to about 135kts at the surface. While the current official setting of 135kts might lead one to believe that there is no intensification recently (since the previous official setting was 140kts), the fact is, the pressure has dropped, recon wind measurements have come up, and Dvorak estimates at 12Z were already up slightly (18Z estimates are not in yet). In other words, Isabel may have been down to 125-130kts earlier in the day. That is no longer the case, as she is a solid 135kt hurricane. And, with the pressure having dropped, we cannot be certain that this daily rebound is completed yet... Isabel could bounce back to 140kts (Category 5) yet again later today. That's neither here nor there in the current conditions... the point now is that she is at 135kts.
In terms of motion, using the long-term motion from recon fixes... the best data available, we get a motion of 286 degrees at 12kts. Her position at 18Z is 23.8N/66.9W. It should be noted that this position and motion leans to the southwest of the more northern models, and to the northeast of the more southern models. This may help in determining the proper model solution. Although, some of the trick to the forecast comes later in the period with the trough interaction. But, some of it is now... how soon the models turn Isabel and how sharply they turn her.
Model/Technical Discussion: Like yesterday, I'm gonig to break down each model one at a time. Once again, I won't provide a massive analysis of each one, but just a basic overview, and where each has landfall. As I've been writing, the new UKMET has come in, and it has shifted north slightly. So, while we have greatly increased model convergence overall, on the fine scale we've actually seen some slight divergence as the GFS/UKMET nudge north and the NOGAPS nudges south. At any rate, here's a breakdown of each of the solutions...
12Z GFS - The 12Z GFS begins impacting the East Coast indirectly as early as Wed morning, as confluence aided by Isabel enhances frontal precip across the Outer Banks of NC. Direct impact holds off in the same area until Thursday morning. Isabel then heads NNW a short distance off the coast of NC/VA/MD/DE. As the NNW motion continues and the concave shape of the coastline hits the point where it begins jutting back out (around NJ), Isabel comes ashore. The precise landfall point is tough to say, but, basically, the GFS takes Isabel across Cape May and into the Delaware Bay overnight Thursday and into Friday.
12Z ETA - The ETA still doesn't go out far enough to predict landfall. However, by H+84 (Wed PM) the ETA position is well SSW of the GFS. Upstream the ETA has more jet energy coming down the back side of the late week trough than the GFS shows. This should allow more digging, a potentially stronger ridge, and a further west track. Indeed, over the Atlantic, the 500mb ridge on the ETA is stronger and stretched further to the west. Thus, even if Isabel is near the GFS' position by then (the ETA is typically poor in predicting tropical cyclone tracks), the ETA would imply a more significant westward bend into NC/VA or at least the Delmarva.
12Z GGEM - Big shanges in the Canadian model today. The absolute insistence of a Long Island/New England landfall has been abandoned. With more Atlantic ridging it drives Isabel to a faster forward motion further west. By Thu AM the GEM has Isabel skirting past Cape Hatteras and Norfolk. But with the trough digging and the ridge getting stronger, Isabel does not continue N or even NNW. Rather, she then turns more towards the NW, up the Chesapeake Bay and up into MD/PA. This is a fairly early landfall (Thursday), which is one of the aspects that helps Isabel head further west.
12Z NOGAPS - The NOGAPS is SW of most other model solutions, and SW of its previous run... slightly. I've stated up front that it has landfall near Morehead City. In reality, upon closer inspection, the landfall looks even a bit further south... but only a bit, down towards New River Inlet. Landfall occurs by midday Thursday. After landfall Isabel heads NWward into SW VA, then on into WV and E OH.
12Z GFDL - The GFDL is fairly close to the GEM in that it skirts Isabel past Cape Hatteras and Norfolk. It does have a little less westward bend at/fter landfall than the GEM, but otherwise is similar. After passing Norfolk, it brings Isabel inland near Wallops Island and up the Chesapeake Bay. Once inland, the GFDL sends Isabel up through PA and NY. The timing of landfall is around Thursday morning... also fairly early and fairly similar to the GEM. The intensity at landfall on the GFDL is a comparatively (compared to now) meek 80kts. Keep in mind, however, that the GFDL initializes the intensity poorly... at 115kts.
12Z UKMET - The UKMET has shifted a fair bit north, but not so much as to introduce significant divergence. This is very possibly related to the UKMET being a bit slow compared to the other models. This gives the trough more time to progress eastward and, as such, though Isabel still cuts to the NNW or NW, she does so from a further east starting point. So, she the UK has Isabel skirting up past Hatteras, Norfolk, and the Delmarva just offshore. She then bends to the NW up into the Delaware Bay... much like the GFS.
00Z MM5 - The MM% leans towards the left side of the model solutions. By Thursday morning it has Isabel making landfall, just clipping Cape Hatteras. Thereafter, the motion continues NW up through the SW coast of the Chesapeake Bay then NW through W MD/E WV.
12Z Sat ECMWF - The EC has been, undoubtedly, the most consistent of all of the models. It actually has a slightly later landfall than most models. As such, it starts further east than most models, moving past Cape Hatteras at a greater distance. However, the EC also has more ridging. As a result, it turns Isabel more abruptly to the left. The result is that Isabel comes crashing ashore near or just north of Norfolk on Friday.
Synoptically, I am again at a loss. The situation has been discussed in detail the past several days and, quite frankly, everything is (so far!) evolving exactly as expected. Isabel is presently turning a bit more towards the north, as the initial trough passes by to the north and weakens the ridge. Actually, this trough is only just beginning to erode the ridge. It doesn't completely pull out for another couple of days yet. As such, it should keep the ridge weakness in place, allowing Isabel to arch around more and more towards the north. Then, by mid-week, as that trough exits and the next, stronger one digs in, the Atlantic ridge should re-strengthen and curl Isabel back around to a more NNW or NW motion... depending on how strong one believes the ridge will get. This should lead to landfall somewhere near where the models indicate Thursday (or perhaps, if landfall is far enough north, early Friday). The breadth of model solutions is reasonably well packed, indicating landfall somewhere between just south of Morehead City, NC and the Delaware Bay.
My thinking: Before giving you my prediction, let me just point out the some new recon data has come in. It has measured the same central pressure as an hour or so previously. However, the 700mb height has dropped a bit... indicative of a pressure fall. The height fall was small, which is why the pressure didn't drop. Indeed, I would NOT use this height fall to say the Isabel is intensifying... that would be a huge leap, especially since deep convection is NOT increasing at this time. I would, however, take it to mean that Isabel is at least stable... holding steady as a 135kt hurricane. Due to a slight decrease in the deepest convection, Dvorak estimates have actually decreased a bit. However, as TPC/NHC noted in situations where a storm is so well organized, the satellite estimates can, at times, underestimate a storm. So, recon is our primary indicator.
As for my prediction... well, it hasn't changed much. Mainly, confidence is increased due to the shifting of the GFDL and the GEM. Confidence has not increased by leaps and bounds, though, as the subtle eastward shift of the GFS/UKMET contrasts with the slight westward shift of the NOGAPS. But, I have arrived at the following conclusion...
The UKMET initialization was too far to the northeast, albeit very slightly. Meanwhile, on Isabel's current heading, it seems highly likely that she will get at least a shade west of the UKMET track during the next 24 to 48 hours. Meanwhile, the GFS' slightly north position seems to be due to a different issue causing slightly less ridging in the Atlantic. The GFS' tendency to smash down ridges too much, too soon is well documented and established. As we get nearer to a shorter range solution this bias should dissipate. But, at this time frame, we should still expect a small bias to occur.
On the flip side, the NOGAPS is on its own being so far south. Not that it is "bad"... it is certainly not outlandishly far to the south. But, since it is on its own, I have to be skeptical. If I could find a reason to believe the NOGAPS... fine. However, in the very early going it appears to have Isabel on a slightly too due west course... but that is tough to judge precisely. So, I'm hesitant to simply disregard the NOGAPS, but... as a slight outlier, I am at least downweighting it.
That leaves us, essentially, with landfall somewhere between Cape Hatteras and along the Delmarva. Frankly, with landfall still about four days away as I write this (perhaps three days away, depending on when you're reading this), leaving it at that... between Hatteras and the Delmarva... would be fine. Forecast skill out that far doesn't allow us to fine tune any more than that. However, just to give you an idea of precisely what I'm thinking, I'm leaning south of the GEM/GFDL, since they've been trending west, but I also don't know that the westward component will get Isabel around Hatteras without landfall, but then in near Norfolk. That's a tough angle and the westward component will be very close to being able to support that. So, I think Isabel will scape along the coast from Hatteras up to Norfolk before officially going inland just north of Norfolk. Of course, like I said, that's too specific when we're still a few days out. So, take that only as rough guidance and tune back in for updates! Incidentally, I should note that my expectation of landfall timing is sometime Thursday. With the models trending faster, and the models having been too slow on the vast majority of hurricanes this season... I like the faster solutions. So, I'm not going with a Friday landfall, but Thursday, instead.
As for the intensity at landfall, I couldn't agree more with TPC/NHC in their 11AM Sunday discussion. In fact, they pointed out something I've been arguing for days now... the model prediction of increased shear is in error. The model track positions place Isabel under no shear, beneath an upper ridge... actually ideal for development. The strong shear is on the outskirts around the edge of the ridge. Certainly, given Isabel's current slight lack of deep convection, combined with the decreased Dvorak estimates, there could be some minor weakening in the short term. In the long term, just before landfall, the complex pattern evolution could also distort Isabel, even if it doesn't shear her, enough to induce some further weakening. As such, I certainly don't see her coming ahshore as a 135kt hurricane, as she is now. But, I also don't see her coming in as a relatively paltry 70-85kt hurricane, as indicated by the various tropical cyclone intensity models. TPC/NHC has her near 110kts at landfall. I had been advetising about 100kts. Looking at a 4-day forecast, 10kts is within the noise. So, while I'm keeping my prediction as 100kts at landfall, I would absolutely not be shocked if it were closer to 110kts (nor would I be shocked if it were 90-95kts).
At this stage of the game, it is too soon for anyone in the Mid-Atlantic to be boarding up windows, or taking any such major precautionary steps. However, folks from coastal NC through NJ should at least be taking some preliminary precautions. For example... making sure you have flashlights with fresh batteries, bringing in loose objects from outdoors (that could wait until last minute, but it is just easiest to do now, if possible, to avoid having to do it later, when more critical preparations are needed), coastal residents should be aware of their evacuation routes and local shelters, etc., etc. Also, one of the most important things to do over the next day or so is to stay informed. Based on the position of the synoptic features and the timeframe in which the models perform well, I suspect the forecast for Isabel will come into better focus tomorrow and, then, will really get focused in on Tuesday. So, stay on top of the situation so that you'll know what, if any, preparations you need to make.
Yep. Raleigh.