ATL: CHANTAL - Post-Tropical

[artist]

[tolakram]

Trusting a shear forecast from this is range is risky IMO.

TROPICAL STORM CHANTAL DISCUSSION NUMBER 7
NWS NATIONAL HURRICANE CENTER MIAMI FL AL032013
1100 AM AST TUE JUL 09 2013

THE SATELLITE PRESENTATION IS NOT DISTINCT BUT EXCELLENT RADAR DATA
FROM BARBADOS AND MARTINIQUE SHOW THE WELL-DEFINED CENTER OF
CHANTAL MOVING RAPIDLY WESTWARD ABOUT 25 KNOTS BETWEEN MARTINIQUE
AN ST. LUCIA. A RECONNAISSANCE PLANE REPORTED FLIGHT LEVEL WINDS OF
70 TO 75 KT NORTHEAST OF THE CENTER EARLIER TODAY WITH A MINIMUM
PRESSURE OF 1003 MB. SINCE THAT TIME...THE PRESSURE HAS LEVELED OFF
TO ABOUT 1006 MB. BASED ON MORE REPRESENTIVE OBSERVATIONS FROM THE
PLANE...AND SURROUNDING ISLANDS...THE INITIAL INTENSITY IS SET AT 50
KNOTS. THE ENVIRONMENT AHEAD OF CHANTAL IS NOT VERY FAVORABLE FOR
INTENSIFICATION...AND ONLY A SLIGHT INCREASE IN THE WINDS IS
FORECAST BEFORE CHANTAL CROSSES HISPANIOLA. THE UPPER-LEVEL WINDS
ARE FORECAST TO REMAIN UNFAVORABLE IN THE AREA OF THE BAHAMAS FOR
SIGNIFICANT DEVELOPMENT...AND ONLY SMALL STRENGTHENING IS
ANTICIPATED AFTER THE CYCLONE CROSSES HISPANIOLA. THIS IS IN
AGREEMENT WITH THE TREND OF THE SHIPS/LGEM MODELS.

CHANTAL IS RACING TOWARD THE WEST-NORTHWEST OR 295 DEGREES AT 25
KNOTS. I AM SURPRISED THE SYSTEM EVEN HAS A CLOSED CIRCULATION
MOVING AT THAT SPEED. CHANTAL IS BEING STEERED BY A RATHER STRONG
EASTERLY FLOW SOUTH OF THE SUBTROPICAL RIDGE OVER THE WESTERN
ATLANTIC. HOWEVER...AS THE STORM MOVES OVER THE EASTERN CARIBBEAN
AND HISPANIOLA...THE HIGH TO THE NORTH IS FORECAST TO WEAKEN AND
THE CYCLONE SHOULD TURN MORE TOWARD THE NORTHWEST WITH A DECREASE IN
FORWARD SPEED. BY DAY 4 AND 5 THE STERING CURRENTS WILL BE WEAK AND
CHANTAL WILL PROBABLY MOVE VERY SLOWLY IN THE VICINITY OF THE
NORTHWESTERN BAHAMAS. THE OFFICIAL FORECAST IS SIMILAR TO THE
PREVIOUS ONE AND IS BASICALLY ON TOP OF THE MODEL CONSENSUS.


FORECAST POSITIONS AND MAX WINDS

INIT 09/1500Z 14.4N 61.5W 50 KT 60 MPH
12H 10/0000Z 15.8N 65.0W 55 KT 65 MPH
24H 10/1200Z 17.4N 68.5W 60 KT 70 MPH
36H 11/0000Z 19.3N 71.5W 35 KT 40 MPH...INLAND
48H 11/1200Z 21.3N 73.6W 35 KT 40 MPH
72H 12/1200Z 24.5N 76.0W 45 KT 50 MPH
96H 13/1200Z 26.5N 77.0W 45 KT 50 MPH
120H 14/1200Z 27.5N 78.0W 40 KT 45 MPH

$$
FORECASTER AVILA

[ObsessedMiami]

LOL. It's only July and already I have seen the "Chantal is looking worse than before" post and the "Chantal looks better than earlier" post within three posts of each other! Looks like an interesting season! Buckle up!

[CrazyC83]

the airport has had sustained of 52 KT with a gust to 68 KT

That is likely 10-min sustained too so such would support a 60 kt intensity...

[artist]

000
URNT12 KNHC 091429
VORTEX DATA MESSAGE AL032013
A. 09/14:10:40Z
B. 14 deg 18 min N
061 deg 13 min W
C. NA
D. 40 kt
E. 319 deg 32 nm
F. 065 deg 53 kt
G. 321 deg 36 nm
H. EXTRAP 1008 mb
I. 20 C / 364 m
J. 23 C / 361 m
K. 23 C / NA
L.
M. NA
N. 12345 / 1
O. 0.02 / 2 nm
P. AF302 0203A CHANTAL OB 10
MAX FL WIND 75 KT 035/45 13:43:30Z
SLP EXTRAP FROM BELOW 1500 FT
SPIRAL BAND 16NM ACROSS, 75KTS AT 850MB LEVEL
;

[floridasun78]

their putting higher chance been hurr by wed to 26

['CaneFreak]

I agree and there was no clear justification from the forecaster on duty Avila as to why other than upper level winds will not be favorable. With a ridge sitting on top of it, I just don't see it. I have never really liked Avila's discussions. Most of them just aren't forthcoming.

strange intensity forecast from NHC. They seem to be windshield wipering on intensity

[SouthFloridawx]

Could be due to the high level of uncertainty after Hispaniola.

[tailgater]

I agree and there was no clear justification from the forecaster on duty Avila as to why other than upper level winds will not be favorable. With a ridge sitting on top of it, I just don't see it. I have never really liked Avila's discussions. Most of them just aren't forthcoming.

strange intensity forecast from NHC. They seem to be windshield wipering on intensity

Note the forecaster, just an observation

[floridasun78]

did their change their mind saying REMAIN UNFAVORABLE IN THE AREA OF THE BAHAMAS FOR
SIGNIFICANT DEVELOPMENT...AND ONLY SMALL STRENGTHENING IS
ANTICIPATED AFTER THE CYCLONE CROSSES HISPANIOLA. THIS IS IN
AGREEMENT WITH THE TREND OF THE SHIPS/LGEM MODELS. their say on monday was more FAVORABLE

[ronjon]

NHC in 11am disc reports that conditions will not be favorable for strengthening in the Bahamas yet both the GFDL and HWRF models in their 06z runs show rather rapid intensification. I don't get it. Perhaps some of of our pro Mets can chime in on their reasoning.

[artist]

URNT15 KNHC 091509
AF302 0203A CHANTAL HDOB 30 20130709
150100 1356N 06156W 9696 00378 0125 +225 +197 216005 006 022 000 00
150130 1357N 06155W 9702 00372 0125 +222 +199 224006 008 023 000 00
150200 1358N 06153W 9699 00373 0124 +215 +203 242008 009 023 001 00
150230 1359N 06152W 9697 00374 0123 +209 +207 247010 011 024 001 00
150300 1400N 06151W 9697 00373 //// +203 //// 240014 016 026 001 01
150330 1401N 06150W 9704 00369 //// +199 //// 254014 017 026 001 01
150400 1402N 06149W 9707 00367 //// +198 //// 262009 016 025 002 01
150430 1404N 06147W 9705 00369 //// +197 //// 260009 011 027 003 01
150500 1405N 06146W 9696 00373 0125 +197 //// 252009 011 029 003 01
150530 1406N 06145W 9699 00372 //// +194 //// 250011 012 030 004 01
150600 1407N 06144W 9702 00364 0121 +198 //// 254012 014 030 004 01
150630 1408N 06143W 9707 00359 //// +194 //// 270012 013 029 005 01
150700 1409N 06142W 9695 00367 //// +199 //// 275013 014 026 001 01
150730 1410N 06140W 9701 00357 //// +202 //// 275011 012 026 000 01
150800 1412N 06139W 9699 00356 //// +206 //// 272013 014 026 001 01
150830 1413N 06138W 9697 00355 0098 +219 +211 263012 014 025 000 00
150900 1414N 06137W 9699 00351 0095 +224 +209 253009 011 024 000 00
150930 1415N 06136W 9700 00346 0092 +226 +209 248008 009 024 001 03
151000 1417N 06136W 9695 00350 0090 +225 +212 254009 009 026 000 00
151030 1418N 06137W 9697 00346 //// +213 //// 246016 019 028 001 01
$$

[Aric Dunn]

morning all.. having fun are we..

['CaneFreak]

Yeah...well, I feel that he should have stated that in his discussion instead of just being wishy washy with every model iteration and he didn't even state where the upper level winds were coming from. I think the upper low will be well west of it by then and should not shear it all that much and the upper trough will be well to the north.

Could be due to the high level of uncertainty after Hispaniola.

[Stormlover2012]

Because u can't trust the gfdl and hwrf lol

[artist]

[Bocadude85]

I agree and there was no clear justification from the forecaster on duty Avila as to why other than upper level winds will not be favorable. With a ridge sitting on top of it, I just don't see it. I have never really liked Avila's discussions. Most of them just aren't forthcoming.

strange intensity forecast from NHC. They seem to be windshield wipering on intensity

Yes very strange. The 5am advisory showed Chantal strengtheining to 60mph at 120hrs and now the 11am forecast shows her weakeing to 45mph.. definately a windshield wiper effect.

120H 14/0600Z 28.5N 77.5W 50 KT 60 MPH 5am forecast

120H 14/1200Z 27.5N 78.0W 40 KT 45 MPH 11am forecast

[Alyono]

the airport has had sustained of 52 KT with a gust to 68 KT

That is likely 10-min sustained too so such would support a 60 kt intensity...

its 1 minute

[floridasun78]

NHC in 11am disc reports that conditions will not be favorable for strengthening in the Bahamas yet both the GFDL and HWRF models in their 06z runs show rather rapid intensification. I don't get it. Perhaps some of of our pro Mets can chime in on their reasoning.

only i see maybe upperlow over bahama not moving as fast their forecast going stay longer over bahamas was suppose move over florida

[tolakram]

Note the forecaster, just an observation

Sorry to make an example, but please do not do this. State your opinion of the forecast but leave opinions of forecasters out of it please. Thanks.