ATL: TROPICAL STORM BILL (03L)

[HURAKAN]

[dixiebreeze]

Except for the forecast steering conditions, it is eerie how close Bill is to the Andrew track in 1993. Is there any possibility at all that atmospheric changes could occur to turn Billl more westerly just as Andrew did?

[dixiebreeze]

Andrew synopsis:

Between the 17th and 20th of August, the tropical storm passed south of the center of the high pressure area over the eastern Atlantic. Steering currents carried Andrew closer to a strong upper-level low pressure system centered about 500 n mi to the east-southeast of Bermuda and to a trough that extended southward from the low for a few hundred miles. These currents gradually changed and Andrew decelerated on a course which became northwesterly. This change in heading spared the Lesser Antilles from an encounter with Andrew. The change in track also brought the tropical storm into an environment of strong southwesterly vertical wind shear and quite high surface pressures to its north. Although the estimated maximum wind speed of Andrew varied little then, a rather remarkable evolution occurred.



Satellite images suggest that Andrew produced deep convection only sporadically for several days, mainly in several bursts of about 12 hours duration. Also, the deep convection did not persist. Instead, it was stripped away from the low-level circulation by the strong southwesterly flow at upper levels. Air Force Reserve unit reconnaissance aircraft investigated Andrew and, on the 20th, found that the cyclone had degenerated to the extent that only a diffuse low-level circulation center remained. Andrew's central pressure rose considerably (Fig. 2 [87K GIF]). Nevertheless, the flight-level data indicated that Andrew retained a vigorous circulation aloft. Wind speeds near 70 kt were measured at an altitude of 1500 ft near a convective band lying to the northeast of the low-level center. Hence, Andrew is estimated on 20 August to have been a tropical storm with 40 kt surface winds and an astonishingly high central pressure of 1015 mb (Figs. 2 and 3 [87K GIF]).



Significant changes in the large-scale environment near and downstream from Andrew began by 21 August. Satellite imagery in the water vapor channel indicated that the low aloft to the east-southeast of Bermuda weakened and split. The bulk of the low opened into a trough which retreated northward. That evolution decreased the vertical wind shear over Andrew. The remainder of the low dropped southward to a position just southwest of Andrew where its circulation enhanced the upper-level outflow over the tropical storm. At the same time, a strong and deep high pressure cell formed near the U.S. southeast coast. A ridge built eastward from the high into the southwestern Atlantic with its axis lying just north of Andrew. The associated steering flow over the tropical storm became easterly. Andrew turned toward the west, accelerated to near 16 kt, and quickly intensified.

[stayawaynow]

wow that's like right over my House! If this trend continues, I better start getting prepared, I just told my Father to make sure both Cars are Filled with Gas and all that Jazz, we just went shopping yesterday, so i think we have enough non perisble stuff, may need to get some new Batteries though
We also have a Big Basement where we could set up some Cots and stuff, if it gets real bad

As long as you are not near water.

[SEASON_CANCELED]

Except for the forecast steering conditions, it is eerie how close Bill is to the Andrew track in 1993. Is there any possibility at all that atmospheric changes could occur to turn Billl more westerly just as Andrew did?

Nope

[vbhoutex]

Except for the forecast steering conditions, it is eerie how close Bill is to the Andrew track in 1993. Is there any possibility at all that atmospheric changes could occur to turn Billl more westerly just as Andrew did?

That is pretty much your answer right there.(bolded) The incoming trough and the latitude of Bill pretty much insure that he will continue as predicted by NHC. Impossible for it to happen? No, but there would have to be some massive and rapid changes in the atmosphere over the CONUS and The Atlantic all at one time.(I would place that on the level of catastrophic changes personally).

[storms NC]

Bill sure does like those jogs to the west alot. I know that NHC goes by 12 hours. But this morning he has been going about 290-295 This may be do to his little weakening. LOL from a 4 down to a 3. But that could be alot to someone that would be looking at him come their way. But he is not at this time frame.
How much more west will Bill go?It seem every up date it is a little more to the west. They keep going they will run out of water here.LOL. Now does the trough stay strong or does it weaken as time goes by. Will he catch the train up to the North? I think NHC has done a good job. It is hard to pin down where this storms will go. It is all about timing. It has been 10 years since we here around Wilm that we had a hurricane. I hope it will be many more. Floyd was the last. Yes we had a few TD or TS but that is it.
Any hows this has been a good Storm to watch and learn on. Who knows maybe he has some tricks up his sleeve. He has done good so far. All the Bill's I know are sneaky and bad.LOL

[HURAKAN]

000
URNT15 KNHC 201544
AF304 0403A BILL HDOB 09 20090820
153430 2128N 06211W 6965 03119 0025 +083 +021 267041 042 041 005 00
153500 2129N 06212W 6970 03111 0019 +089 +019 265040 040 042 006 00
153530 2130N 06214W 6965 03117 0030 +078 +019 265038 039 043 008 00
153600 2131N 06215W 6966 03112 0037 +072 +016 272038 039 043 010 00
153630 2132N 06216W 6970 03109 0015 +089 +013 271042 043 042 007 00
153700 2133N 06218W 6967 03110 0011 +092 +013 275043 044 040 006 00
153730 2134N 06219W 6963 03115 0012 +090 +015 277043 043 038 006 00
153800 2134N 06220W 6970 03109 0011 +090 +019 278044 044 038 005 00
153830 2135N 06221W 6965 03116 0007 +091 +022 276043 043 039 004 00
153900 2136N 06223W 6970 03102 0004 +094 +024 276043 043 037 005 00
153930 2137N 06224W 6967 03106 0006 +091 +026 278042 042 038 005 00
154000 2138N 06225W 6965 03108 0006 +090 +026 279040 041 040 005 00
154030 2139N 06227W 6970 03098 0007 +090 +026 279039 040 040 004 00
154100 2140N 06228W 6957 03118 0005 +089 +026 281038 038 041 006 00
154130 2140N 06229W 6963 03102 0003 +087 +024 283039 039 041 005 00
154200 2142N 06231W 6967 03100 0000 +089 +022 285039 040 041 005 00
154230 2143N 06233W 6970 03091 9999 +090 +022 293042 042 041 004 00
154300 2144N 06234W 6962 03105 9995 +092 +022 300042 043 042 004 00
154330 2145N 06236W 6964 03100 9988 +096 +024 304044 044 041 005 00
154400 2146N 06238W 6979 03081 9982 +100 +026 304043 043 040 004 00
$$
;

[HURAKAN]

[JTD]

I am extremely concerned for Halifax and all of Nova Scotia for that matter. It's a major major metropolitan area. If this goes into the Bay of Fundy, the surge values are incredibly high there. And if Bill hits Halifax as a major, Halifax is in very serious trouble indeed.

[HURAKAN]

The convection isn't very strong

[x-y-no]

12z run of the GFS is significantly to the right of the 6z run - a full degree at the 48 hour point (54 hour in the 6z)

Depicts a tighter structure, though.

http://www.nco.ncep.noaa.gov/pmb/nwprod ... n_048l.gif

[x-y-no]

12z GFS at 60 hours:

http://www.nco.ncep.noaa.gov/pmb/nwprod ... n_060l.gif

still significantly to the right of the 6z

[dixiebreeze]

Except for the forecast steering conditions, it is eerie how close Bill is to the Andrew track in 1993. Is there any possibility at all that atmospheric changes could occur to turn Billl more westerly just as Andrew did?

That is pretty much your answer right there.(bolded) The incoming trough and the latitude of Bill pretty much insure that he will continue as predicted by NHC. Impossible for it to happen? No, but there would have to be some massive and rapid changes in the atmosphere over the CONUS and The Atlantic all at one time.(I would place that on the level of catastrophic changes personally).

Thanks VBhourTex. However, I don't believe Andrew was forecast to make a sharp turn into South Florida, either. That's why I was wondering.

[KWT]

The convection hasn't really been that strong with Bill for a while now but the structure is still pretty impressive I have to admit, even if it is now a category-3.

[HURAKAN]

000
URNT15 KNHC 201554
AF304 0403A BILL HDOB 10 20090820
154430 2147N 06239W 6957 03106 9981 +096 +028 305044 045 041 004 00
154500 2148N 06241W 6971 03086 9983 +095 +030 309046 046 043 004 00
154530 2149N 06243W 6966 03093 9981 +095 +031 311045 045 043 004 00
154600 2150N 06245W 6967 03094 9983 +096 +032 311045 046 043 005 00
154630 2151N 06246W 6965 03095 9982 +096 +032 315047 047 043 004 00
154700 2153N 06248W 6972 03089 9977 +100 +032 317048 048 043 004 00
154730 2154N 06250W 6965 03091 9984 +094 +032 317047 048 042 004 00
154800 2155N 06252W 6969 03089 9984 +096 +031 321048 050 042 006 00
154830 2156N 06253W 6970 03096 9983 +100 +031 320050 051 043 005 00
154900 2157N 06255W 6965 03125 0001 +100 +029 318049 050 043 003 03
154930 2159N 06254W 6967 03100 9994 +096 +027 316047 048 035 004 03
155000 2200N 06253W 6969 03089 9978 +098 +025 313045 046 040 004 00
155030 2202N 06251W 6979 03074 9979 +096 +023 309045 046 039 005 00
155100 2203N 06250W 6970 03079 9980 +092 +022 305046 046 041 005 00
155130 2205N 06248W 6967 03080 9975 +094 +019 307047 048 044 005 00
155200 2206N 06247W 6969 03076 9973 +090 +016 307048 048 046 005 00
155230 2208N 06246W 6965 03080 9966 +094 +013 305048 049 046 006 00
155300 2209N 06244W 6967 03067 9965 +090 +010 309046 047 047 008 00
155330 2210N 06243W 6965 03069 9957 +092 +009 307048 049 049 008 00
155400 2212N 06242W 6969 03050 9941 +094 +007 307050 051 049 008 00
$$
;

[KWT]

12z nearly always appears to be the most right run, I think the run cycle tends to put a bit more energy into the upper features then the other runs.

[x-y-no]

Except for the forecast steering conditions, it is eerie how close Bill is to the Andrew track in 1993. Is there any possibility at all that atmospheric changes could occur to turn Billl more westerly just as Andrew did?

That is pretty much your answer right there.(bolded) The incoming trough and the latitude of Bill pretty much insure that he will continue as predicted by NHC. Impossible for it to happen? No, but there would have to be some massive and rapid changes in the atmosphere over the CONUS and The Atlantic all at one time.(I would place that on the level of catastrophic changes personally).

Thanks VBhourTex. However, I don't believe Andrew was forecast to make a sharp turn into South Florida, either. That's why I was wondering.

Not as sharp a turn as it made, no. But it was forecast to head mostly west as the ridge extended well over it. Very, very different setup from what we have now.

[x-y-no]

Inbound SW quadrant.

[dixiebreeze]

Notice that the banding is veering more north and west now and the eye banding has filled in on the west side:

http://www.ssd.noaa.gov/goes/flt/t2/flash-rb.html