ATL: IRENE - Remnants - Discussion

[ConvergenceZone]

Since the trend is your friend and the eastward trend continues, I'm expecting to see this curving out to sea by tonight (my opinion)...I honestly thought they would curve it out to sea with the last advisory at 11:00 AM, but they seem to be gradually moving the track eastward instead of an abrupt move. But as they said in the last advisory, even their forecast is still left of the model plots.

[clfenwi]

URNT12 KNHC 231730
VORTEX DATA MESSAGE AL092011
A. 23/17:10:50Z
B. 20 deg 38 min N
071 deg 09 min W
C. 700 mb 2898 m
D. 68 kt
E. 043 deg 13 nm
F. 132 deg 65 kt
G. 043 deg 13 nm
H. 978 mb
I. 9 C / 3114 m
J. 15 C / 3109 m
K. 11 C / NA
L. OPEN SW
M. C25
N. 12345 / 7
O. 0.02 / 2 nm
P. AF302 0809A IRENE OB 17
MAX FL WIND 69 KT E QUAD 16:02:10Z
MAX OUTBOUND FL WIND 67 KT N QUAD 17:17:00Z
SFC NOT VISIBLE
BKN CLDS BLO

[ozonepete]

Lifted Index is running around -6 to -7 over the eastern end of Cuba.

Afternoon heating will likely fire some strong thunderstorms and fill in the mid-level dry slot to the west of Irene.

If that happens, it should help to get Irene back on track.

Nice analysis, G. And the biggest boost will come when the eastern end of the core passes west of Haiti tomorrow.

[mascpa]

What is the relevance of the "Lifted Index"? I don't know that I have ever heard that term before.

[RL3AO]

What is the relevance of the "Lifted Index"? I don't know that I have ever heard that term before.

Its a measurement of atmospheric instability normally used in severe weather events.

[AdamFirst]

Since the trend is your friend and the eastward trend continues, I'm expecting to see this curving out to sea by tonight (my opinion)...I honestly thought they would curve it out to sea with the last advisory at 11:00 AM, but they seem to be gradually moving the track eastward instead of an abrupt move. But as they said in the last advisory, even their forecast is still left of the model plots.

GFS, HWRF and NOGAPS have all trended west this run.

[ColinDelia]

What is the relevance of the "Lifted Index"? I don't know that I have ever heard that term before.

negative values = unstable atmosphere

[clfenwi]

URNT15 KNHC 231739
AF302 0809A IRENE HDOB 29 20110823
172900 2138N 07110W 6913 03175 0000 +088 //// 097042 042 048 003 01
172930 2140N 07110W 6920 03172 0001 +091 //// 095046 047 046 000 01
173000 2141N 07110W 6912 03183 0004 +091 //// 094048 051 046 005 01
173030 2143N 07110W 6917 03181 0006 +091 //// 097050 051 047 005 01
173100 2145N 07110W 6914 03182 0011 +088 //// 099053 053 045 001 05
173130 2147N 07109W 6916 03182 0015 +087 //// 101054 055 045 000 05
173200 2149N 07109W 6914 03186 0016 +086 //// 103052 053 044 000 05
173230 2151N 07109W 6914 03187 0022 +084 +079 103052 053 042 002 00
173300 2152N 07109W 6916 03184 0026 +080 +077 102049 050 042 001 00
173330 2154N 07109W 6913 03188 0030 +080 +073 099048 050 044 006 00
173400 2156N 07109W 6914 03188 0035 +075 //// 099048 050 044 001 05
173430 2158N 07110W 6906 03196 0029 +079 +069 097043 044 /// /// 03
173500 2158N 07112W 6920 03184 0034 +079 +072 092041 043 045 000 03
173530 2158N 07114W 6914 03189 0035 +078 +075 092043 043 045 000 03
173600 2158N 07116W 6914 03189 0030 +080 +079 093044 045 045 000 03
173630 2158N 07119W 6915 03190 0032 +080 //// 092045 046 044 002 01
173700 2159N 07121W 6914 03192 0031 +082 +076 095046 047 045 002 03
173730 2159N 07123W 6913 03194 0035 +081 +072 094045 047 044 000 03
173800 2159N 07126W 6916 03192 0034 +082 +071 095042 042 045 001 00
173830 2159N 07128W 6914 03195 0043 +070 //// 089044 045 045 000 05

[ozonepete]

What is the relevance of the "Lifted Index"? I don't know that I have ever heard that term before.

Here's the NWS definition:
Lifted Index
(abbrev. LI)- A common measure of atmospheric instability. Its value is obtained by computing the temperature that air near the ground would have if it were lifted to some higher level (around 18,000 feet, usually) and comparing that temperature to the actual temperature at that level. Negative values indicate instability - the more negative, the more unstable the air is, and the stronger the updrafts are likely to be with any developing thunderstorms. However there are no "magic numbers" or threshold LI values below which severe weather becomes imminent.

We usually assume good lift as numbers reach -2 or -3. -6 or -7 is quite strong.

[mascpa]

What is the relevance of the "Lifted Index"? I don't know that I have ever heard that term before.

Its a measurement of atmospheric instability normally used in severe weather events.

Thanks

[tailgater]

the last 3 fixes show a movement of 300 degrees.

[mascpa]

What is the relevance of the "Lifted Index"? I don't know that I have ever heard that term before.

negative values = unstable atmosphere

Thanks

[jhpigott]

Since the trend is your friend and the eastward trend continues, I'm expecting to see this curving out to sea by tonight (my opinion)...I honestly thought they would curve it out to sea with the last advisory at 11:00 AM, but they seem to be gradually moving the track eastward instead of an abrupt move. But as they said in the last advisory, even their forecast is still left of the model plots.

GFS, HWRF and NOGAPS have all trended west this run.

Adam- could you post or link in the models thread the new HWRF? I see the new GFS and NOGAPS, but not the HWRF.

[ConvergenceZone]

Since the trend is your friend and the eastward trend continues, I'm expecting to see this curving out to sea by tonight (my opinion)...I honestly thought they would curve it out to sea with the last advisory at 11:00 AM, but they seem to be gradually moving the track eastward instead of an abrupt move. But as they said in the last advisory, even their forecast is still left of the model plots.

GFS, HWRF and NOGAPS have all trended west this run.

Hmm, well If the trend east has stopped and they are in the process of reversing, you might be onto something, but I'd like to see that happen for 2 to 3 runs to determine to see if the Trend East will continue or not...

[RL3AO]

North eyewall dropsonde

Code: Select all

988mb (Surface)   65° (from the ENE)   49 knots (56 mph)
987mb   65° (from the ENE)   50 knots (58 mph)
982mb   55° (from the NE)   74 knots (85 mph)
980mb   55° (from the NE)   79 knots (91 mph)
967mb   65° (from the ENE)   77 knots (89 mph)
958mb   65° (from the ENE)   82 knots (94 mph)
951mb   70° (from the ENE)   77 knots (89 mph)
937mb   70° (from the ENE)   82 knots (94 mph)
929mb   75° (from the ENE)   81 knots (93 mph)
916mb   80° (from the E)   93 knots (107 mph)

The winds are there but they aren't mixing down to the surface very well.

[AdamFirst]

Its not a dramatic shift west but it seems to be right through the core of the Bahamas instead of east of the islands.

GFDL hasn't started running yet.

More details in the models thread...

[SouthFloridawx]

Things are not looking good for NC, Mid-Atlantic or the Northeast.

[tolakram]

000
URNT12 KNHC 231730
VORTEX DATA MESSAGE AL092011
A. 23/17:10:50Z
B. 20 deg 38 min N
071 deg 09 min W
C. 700 mb 2898 m
D. 68 kt
E. 043 deg 13 nm
F. 132 deg 65 kt
G. 043 deg 13 nm
H. 978 mb
I. 9 C / 3114 m
J. 15 C / 3109 m
K. 11 C / NA
L. OPEN SW
M. C25
N. 12345 / 7
O. 0.02 / 2 nm
P. AF302 0809A IRENE OB 17
MAX FL WIND 69 KT E QUAD 16:02:10Z
MAX OUTBOUND FL WIND 67 KT N QUAD 17:17:00Z
SFC NOT VISIBLE
BKN CLDS BLO
;

Maintaining pressure, eyewall still open.

[ozonepete]

Since the trend is your friend and the eastward trend continues, I'm expecting to see this curving out to sea by tonight (my opinion)...I honestly thought they would curve it out to sea with the last advisory at 11:00 AM, but they seem to be gradually moving the track eastward instead of an abrupt move. But as they said in the last advisory, even their forecast is still left of the model plots.

GFS, HWRF and NOGAPS have all trended west this run.

Hmm, well If the trend east has stopped and they are in the process of reversing, you might be onto something, but I'd like to see that happen for 2 to 3 runs to determine to see if the Trend East will continue or not...

At this point, as Irene is getting closer to the mainland, the forecast tracks will probably swing both west and east and gradually settle on a fairly narrow consensus by late tomorrow or Thursday.

[eastcoastFL]

the last 3 fixes show a movement of 300 degrees.

i have to disagree