EPAC: IRWIN - Post - Tropical

Moderator: S2k Moderators

Message
Author
User avatar
Yellow Evan
Category 5
Category 5
Posts: 10525
Age: 20
Joined: Fri Jul 15, 2011 12:48 pm
Location: Henderson, Nevada/Norman, Oklahoma
Contact:

#21 Postby Yellow Evan » Thu Oct 06, 2011 7:34 pm

No IMO.
0 likes   

CrazyC83
Professional-Met
Professional-Met
Posts: 26962
Joined: Tue Mar 07, 2006 11:57 pm
Location: Deep South, for the first time!

#22 Postby CrazyC83 » Thu Oct 06, 2011 7:42 pm

EP, 11, 2011100700, , BEST, 0, 131N, 1186W, 55, 994, TS
0 likes   

bexar
Tropical Storm
Tropical Storm
Posts: 182
Joined: Sat Aug 20, 2011 11:23 am

#23 Postby bexar » Thu Oct 06, 2011 8:16 pm

If this becomes a hurricane, which is very likely, it would be the first time ever the name "Irwin" becomes one. The last five times it was used, all of them were only of TS strength.
0 likes   

CrazyC83
Professional-Met
Professional-Met
Posts: 26962
Joined: Tue Mar 07, 2006 11:57 pm
Location: Deep South, for the first time!

#24 Postby CrazyC83 » Thu Oct 06, 2011 8:27 pm

Could this be RI'ing and headed towards monster status?
0 likes   

User avatar
brunota2003
S2K Supporter
S2K Supporter
Posts: 9477
Age: 27
Joined: Sat Jul 30, 2005 9:56 pm
Location: Stanton, KY...formerly Havelock, NC
Contact:

Re: EPAC: IRWIN - Tropical Storm

#25 Postby brunota2003 » Thu Oct 06, 2011 8:44 pm

Well, if you wanted to be technical, all it needs is a 5 knot increase on the 06 UTC BT and it will have met the requirements for RI (30 knots or greater in 24 hours). 6 Oct 06 UTC BT has Irwin at 30 knots, and the 7 Oct 00 UTC BT has Irwin at 55 knots (25 knots in 18 hours).

Personal Forecast Disclaimer:
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.


As far as RI goes for the rest of Irwin's life, I would like more time/updates on CIMSS before guessing...but it certainly appears there is a high chance Irwin undergoes RI. I'd put the chances close to 70% that a cycle of RI starts within the next 24 hours (not counting 30 to 60 knots, if it occurs). I cannot say for certain, but it looked like the indicator may have popped up around 20 UTC (4 pm EDT)...which would mean RI would begin around 02 to 04 UTC (10 pm to 12 am EDT). My main issue is that there was an image that only caught half of the circulation, so I can only see a little over half of the inner core. If RI did occur, with the BT saying 55 knots at 00 UTC, that would put the intensity at at least 85 knots by 00 UTC tomorrow.
0 likes   

User avatar
cycloneye
Storm2k Moderator
Storm2k Moderator
Posts: 112118
Age: 61
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: EPAC: IRWIN - Tropical Storm

#26 Postby cycloneye » Thu Oct 06, 2011 9:56 pm

TROPICAL STORM IRWIN DISCUSSION NUMBER 4
NWS NATIONAL HURRICANE CENTER MIAMI FL EP112011
800 PM PDT THU OCT 06 2011

IRWIN HAS CONTINUED TO STRENGTHEN DURING THE PAST SEVERAL HOURS. A
TRMM OVERPASS NEAR 2000 UTC INDICATED A WELL-ORGANIZED LOW-LEVEL
CIRCULATION CENTER...AND SINCE THAT TIME THE CLOUD TOPS HAVE BEEN
COOLING IN WHAT APPEARS TO BE A DEVELOPING EYEWALL. SATELLITE
INTENSITY ESTIMATES FROM TAFB AND SAB ARE NOW 55 KT. THE INITIAL
INTENSITY IS THUS INCREASED TO 55 KT...AND THIS COULD BE
CONSERVATIVE. THE CIRRUS OUTFLOW IS GOOD TO EXCELLENT OVER THE
NORTHWESTERN SEMICIRCLE.

THE INITIAL MOTION IS AGAIN A LITTLE FASTER THAN BEFORE AT 295/9.
IRWIN IS ON THE SOUTH SIDE OF A MID-LEVEL RIDGE THAT IS FORECAST TO
WEAKEN AS A LARGE DEEP-LAYER TROUGH OVER THE WESTERN UNITED STATES
DIGS SOUTHWARD. THIS...IN COMBINATION WITH A LARGE AREA OF
DEVELOPING WESTERLY LOW-LEVEL FLOW ASSOCIATED WITH IRWIN AND
TROPICAL STORM JOVA TO THE EAST...IS EXPECTED TO STOP THE CURRENT
MOTION WITHIN 24-36 HOURS. AFTER THAT...THE TRACK FORECAST
GUIDANCE IS IN GOOD AGREEMENT THAT IRWIN SHOULD MOVE
EAST-NORTHEASTWARD...ALTHOUGH THERE IS A SIGNIFICANT SPREAD IN THE
SPEED BETWEEN THE FASTER GFS AND THE SLOWER ECMWF/UKMET. THE NEW
FORECAST TRACK IS SHIFTED TO THE WEST DURING THE FIRST 48 HOURS
BASED ON THE CURRENT POSITION AND MOTION. AFTER THAT...IT IS
SIMILAR TO THE PREVIOUS FORECAST. AT THIS TIME...IT APPEARS THAT
IRWIN AND JOVA ARE FAR ENOUGH APART THAT THERE WILL NOT BE ANY
DIRECT INTERACTION BETWEEN THE STORMS TO AFFECT THE MOTION.

IRWIN IS CURRENTLY IN A LIGHT/MODERATE VERTICAL WINDS SHEAR
ENVIRONMENT OVER SEA SURFACE TEMPERATURES OF 28C. THESE...COMBINED
WITH THE CURRENT CONVECTIVE ORGANIZATION...ARE FAVORABLE CONDITIONS
FOR RAPID INTENSIFICATION. THE RAPID INTENSIFICATION INDEX OF THE
SHIPS MODEL SHOWS A 40 PERCENT CHANCE OF OF 25 KT OF STRENGTHENING
DURING THE NEXT 24 HOURS...AND THE SHIPS MODEL ITSELF FORECASTS AN
80 KT INTENSITY IN 24 HOURS. BASED ON THIS...THE INTENSITY
FORECAST DURING THE FIRST 48 HOURS IS INCREASED CONSIDERABLY FROM
THE PREVIOUS FORECAST. AFTER THAT TIME...THE INTENSITY GUIDANCE
NOW SUGGESTS THAT INCREASING EASTERLY SHEAR WILL CAUSE IRWIN TO
WEAKEN. BASED ON THIS...THE INTENSITY FORECAST NOW SHOWS A SLOW
WEAKENING AFTER 48 HOURS.

FORECAST POSITIONS AND MAX WINDS

INIT 07/0300Z 13.4N 119.0W 55 KT 65 MPH
12H 07/1200Z 13.7N 119.3W 65 KT 75 MPH
24H 08/0000Z 14.1N 119.4W 80 KT 90 MPH
36H 08/1200Z 14.4N 119.4W 85 KT 100 MPH
48H 09/0000Z 14.5N 119.0W 85 KT 100 MPH
72H 10/0000Z 14.5N 117.0W 80 KT 90 MPH
96H 11/0000Z 15.5N 113.5W 75 KT 85 MPH
120H 12/0000Z 16.5N 110.5W 70 KT 80 MPH

$$
FORECASTER BEVEN
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
brunota2003
S2K Supporter
S2K Supporter
Posts: 9477
Age: 27
Joined: Sat Jul 30, 2005 9:56 pm
Location: Stanton, KY...formerly Havelock, NC
Contact:

Re: EPAC: IRWIN - Tropical Storm

#27 Postby brunota2003 » Thu Oct 06, 2011 11:53 pm

brunota2003 wrote:Well, if you wanted to be technical, all it needs is a 5 knot increase on the 06 UTC BT and it will have met the requirements for RI (30 knots or greater in 24 hours). 6 Oct 06 UTC BT has Irwin at 30 knots, and the 7 Oct 00 UTC BT has Irwin at 55 knots (25 knots in 18 hours).

Personal Forecast Disclaimer:
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.


As far as RI goes for the rest of Irwin's life, I would like more time/updates on CIMSS before guessing...but it certainly appears there is a high chance Irwin undergoes RI. I'd put the chances close to 70% that a cycle of RI starts within the next 24 hours (not counting 30 to 60 knots, if it occurs). I cannot say for certain, but it looked like the indicator may have popped up around 20 UTC (4 pm EDT)...which would mean RI would begin around 02 to 04 UTC (10 pm to 12 am EDT). My main issue is that there was an image that only caught half of the circulation, so I can only see a little over half of the inner core. If RI did occur, with the BT saying 55 knots at 00 UTC, that would put the intensity at at least 85 knots by 00 UTC tomorrow.

CIMSS updated...definitely my indicator is there (and got a good pass into the system). Bumping the chances up to 90% (of RI starting/occurring in the next 24 hours), barring anything unusual happening. The convection is decreasing, but that can easily change as we go through the night and approach DMIN.

As far as a forecast goes...not sure how rapid the strengthening could be...there is light shear, very warm waters, everything is near perfect...so perhaps as high as 100 or 110 knots by 8 pm EDT tomorrow, if it does strengthen rapidly.

Also of note:

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 07 OCT 2011 Time : 040000 UTC
Lat : 13:27:57 N Lon : 119:05:08 W


CI# /Pressure/ Vmax
4.3 / 983.9mb/ 72.2kt


Final T# Adj T# Raw T#
4.3 4.3 3.4

Center Temp : -62.1C Cloud Region Temp : -61.6C

Scene Type : UNIFORM CDO CLOUD REGION w/ MW EYE
0 likes   

User avatar
somethingfunny
ChatStaff
ChatStaff
Posts: 3688
Age: 30
Joined: Thu May 31, 2007 10:30 pm
Location: Eastern Dallas County, TX

Re: EPAC: IRWIN - Tropical Storm

#28 Postby somethingfunny » Fri Oct 07, 2011 12:15 am

Eventual landfall is not a done deal yet for Irwin. Some models are suggesting it meanders and weakens just off the Mexican coast. Though Irwin may become the more powerful hurricane, Jova is definitely a more imminent threat.
0 likes   
I am not a meteorologist, and any posts made by me are not official forecasts or to be used as such. These posts are just my opinions and are probably silly opinions.

Click here to join us in Storm2k.org's official (and operational!) chatroom!

Rules for the Storm2k.org chatroom

User avatar
Kingarabian
S2K Supporter
S2K Supporter
Posts: 8564
Joined: Sat Aug 08, 2009 3:06 am
Location: Honolulu, Hawaii

#29 Postby Kingarabian » Fri Oct 07, 2011 2:50 am

Gonna go out on a limb and say it will be a Hurricane next advisory.
0 likes   
Image

bexar
Tropical Storm
Tropical Storm
Posts: 182
Joined: Sat Aug 20, 2011 11:23 am

#30 Postby bexar » Fri Oct 07, 2011 3:40 am

Now Hurricane Irwin at 70 KTs
0 likes   

User avatar
cycloneye
Storm2k Moderator
Storm2k Moderator
Posts: 112118
Age: 61
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: EPAC: IRWIN - Hurricane

#31 Postby cycloneye » Fri Oct 07, 2011 5:58 am

HURRICANE IRWIN DISCUSSION NUMBER 5
NWS NATIONAL HURRICANE CENTER MIAMI FL EP112011
200 AM PDT FRI OCT 07 2011

OVER THE PAST COUPLE OF HOURS...AN EYE HAS BECOME EVIDENT IN
INFRARED SATELLITE IMAGERY AND IS GRADUALLY WARMING. THERE ALSO
WAS A LULL IN THE DEEP CONVECTION...BUT NEW CONVECTION IS
DEVELOPING IN THE EYEWALL. DVORAK ESTIMATES FROM TAFB AND SAB WERE
65 KT AT 0600 UTC...AND THE LATEST UW-CIMSS ADT ESTIMATE IS 70-75
KT. BASED ON THESE DATA AND THE IMPROVED CONVECTION SINCE THE
SYNOPTIC HOUR...IRWIN IS NOW A HURRICANE WITH AN INITIAL INTENSITY
OF 70 KT.

IRWIN HAS NOT SLOWED DOWN AS HAS BEEN FORECAST...AND THE INITIAL
MOTION IS 300/9 KT. ALL OF THE TRACK GUIDANCE INDICATES THAT THE
HURRICANE SHOULD VIRTUALLY STOP ON A DIME DURING THE NEXT 24 HOURS
AS THE STEERING CURRENTS AROUND THE CYCLONE COLLAPSE. A VERY SLOW
EASTWARD TURN IS EXPECTED BY 36 HOURS AS IRWIN BARELY FEELS THE
INFLUENCE OF A MID-LATITUDE TROUGH OVER THE SOUTHWESTERN UNITED
STATES. ALTHOUGH THE TROUGH IS FORECAST TO REMAIN BROAD...THE
WESTERLIES ARE EXPECTED TO MOVE FARTHER SOUTH AND BEGIN TO
ACCELERATE IRWIN EASTWARD BY DAYS 4 AND 5. THE TRACK MODELS AGREE
ON THE GENERAL FORECAST PATH BUT DIFFER ON THE FORECAST SPEED...
ESPECIALLY BY DAYS 4 AND 5. THE NEW OFFICIAL FORECAST IS A LITTLE
SOUTH OF THE PREVIOUS FORECAST AT THAT TIME...LEANING IN THE
DIRECTION OF THE ECMWF AND THE MODEL CONSENSUS.

IRWIN HAS BEEN GOING THROUGH A PERIOD OF RAPID INTENSIFICATION WITH
A CHANGE OF 50 KT OVER THE PAST 24 HOURS. AN 0145 UTC WINDSAT PASS
INDICATED THAT IRWIN HAS A STRUCTURE THAT IS CONDUCIVE FOR RAPID
INTENSIFICATION...AND THE HURRICANE IS OVER SSTS OF ABOUT
28C...SUFFICIENTLY WARM ENOUGH TO SUPPORT ADDITIONAL STRENGTHENING.
IN FACT...THE RI INDEX IN THE NEWEST SHIPS GUIDANCE INDICATES THAT
THERE IS A 3 IN 10 CHANCE OF ANOTHER PERIOD OF RI DURING THE NEXT
24 HOURS. THE OFFICIAL FORECAST IS THEREFORE HIGHER THAN MUCH OF
THE GUIDANCE FOR THE FIRST 24 HOURS BEFORE LEVELING OFF NEAR THE
SHIPS OUTPUT FROM 36-72 HOURS. ONE ARGUMENT AGAINST POSSIBLE RI IS
THE FACT THAT THE THERMOCLINE IS RELATIVELY SHALLOW NEAR
IRWIN...AND THE EXPECTED SLOW MOTION OVER THE NEXT 48 HOURS COULD
UPWELL COLDER WATER AND LIMIT INTENSIFICATION. GRADUAL WEAKENING
IS INDICATED DURING DAYS 3 THROUGH 5 DUE TO AN INCREASE IN VERTICAL
SHEAR...BUT THE OFFICIAL FORECAST IS STILL HIGHER THAN THE
STATISTICAL GUIDANCE DURING THAT PERIOD.

FORECAST POSITIONS AND MAX WINDS

INIT 07/0900Z 13.7N 119.8W 70 KT 80 MPH
12H 07/1800Z 14.1N 120.1W 80 KT 90 MPH
24H 08/0600Z 14.4N 120.2W 90 KT 105 MPH
36H 08/1800Z 14.4N 119.8W 90 KT 105 MPH
48H 09/0600Z 14.4N 119.0W 85 KT 100 MPH
72H 10/0600Z 15.0N 116.5W 80 KT 90 MPH
96H 11/0600Z 15.5N 113.0W 75 KT 85 MPH
120H 12/0600Z 16.0N 109.5W 70 KT 80 MPH

$$
FORECASTER BERG
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

RL3AO
Moderator-Pro Met
Moderator-Pro Met
Posts: 15983
Joined: Thu Jun 14, 2007 10:03 pm
Location: NC

#32 Postby RL3AO » Fri Oct 07, 2011 7:19 am

Always a tough call. NHC usually plays it conservative when RI is ongoing. If it doesn't slow down their forecast busts big.
0 likes   

User avatar
lester
S2K Supporter
S2K Supporter
Posts: 1298
Age: 29
Joined: Sat Aug 27, 2005 5:21 pm
Location: Washington, DC
Contact:

#33 Postby lester » Fri Oct 07, 2011 12:47 pm

000
WTPZ41 KNHC 071443
TCDEP1

HURRICANE IRWIN DISCUSSION NUMBER 6
NWS NATIONAL HURRICANE CENTER MIAMI FL EP112011
800 AM PDT FRI OCT 07 2011

IRWIN HAS A FAIRLY CIRCULAR CENTRAL DENSE OVERCAST WITH SEVERAL
SURROUNDING CONVECTIVE BANDS...BUT AN EYE IS NOT VISIBLE ON
SATELLITE IMAGES AT THIS TIME. BASED ON THE DVORAK EMBEDDED CENTER
PATTERN FOR ESTIMATING INTENSITY...THE CURRENT WIND SPEED IS SET TO
75 KT. ASSUMING THAT THE SYSTEM MOVES ENOUGH SO THAT THE INFLUENCE
OF OCEANIC UPWELLING IS MINIMAL...ADDITIONAL STRENGTHENING IS
ANTICIPATED DURING THE NEXT DAY OR SO. BEYOND ABOUT 48 HOURS...
INCREASING EASTERLY SHEAR SHOULD CAUSE GRADUAL WEAKENING. THE
OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE STATISTICAL-DYNAMICAL
GUIDANCE.

THE HURRICANE APPEARS TO HAVE SLOWED DOWN AND THE INITIAL MOTION IS
ESTIMATED TO BE 300/7. THERE HAS NOT BEEN MUCH CHANGE TO THE TRACK
FORECAST PHILOSOPHY. IRWIN IS EXPECTED TO TURN TOWARD THE EAST
OVER THE NEXT COUPLE OF DAYS AS IT COMES UNDER THE INFLUENCE OF
BROAD MID- TO LOW-LEVEL WESTERLY FLOW. THE OFFICIAL TRACK FORECAST
IS MORE OR LESS ALONG THE SAME TRAJECTORY AS THE PREVIOUS ONE...BUT
SLIGHTLY SLOWER. THIS IS CLOSE TO THE LATEST MULTI-MODEL
CONSENSUS. AS HAS BEEN THE CASE IN PREVIOUS RUNS...THE GFS IS
FASTER THAN THE OFFICIAL FORECAST AND MOST OF THE OTHER DYNAMICAL
MODELS.

THE WIND RADII HAVE BEEN ADJUSTED USING DATA FROM AN EARLIER ASCAT
PASS WHICH SHOWS THE CYCLONE TO BE SMALLER THAN PREVIOUSLY
ESTIMATED OVER THE NORTHERN SEMICIRCLE.

FORECAST POSITIONS AND MAX WINDS

INIT 07/1500Z 13.9N 120.4W 75 KT 85 MPH
12H 08/0000Z 14.2N 120.7W 80 KT 90 MPH
24H 08/1200Z 14.6N 120.6W 90 KT 105 MPH
36H 09/0000Z 14.7N 120.2W 90 KT 105 MPH
48H 09/1200Z 14.7N 119.5W 90 KT 105 MPH
72H 10/1200Z 14.9N 117.0W 80 KT 90 MPH
96H 11/1200Z 15.5N 113.0W 75 KT 85 MPH
120H 12/1200Z 16.5N 109.0W 70 KT 80 MPH

$$
FORECASTER PASCH
0 likes   

User avatar
cycloneye
Storm2k Moderator
Storm2k Moderator
Posts: 112118
Age: 61
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: EPAC: IRWIN - Hurricane

#34 Postby cycloneye » Fri Oct 07, 2011 3:39 pm

HURRICANE IRWIN DISCUSSION NUMBER 7
NWS NATIONAL HURRICANE CENTER MIAMI FL EP112011
200 PM PDT FRI OCT 07 2011

THE CLOUD PATTERN OF THE HURRICANE HAS BECOME A LITTLE BETTER
ORGANIZED OVER THE PAST SEVERAL HOURS WITH MORE DEFINITIVE BANDING
FEATURES AND THE EYE BECOMING APPARENT ON VISIBLE IMAGES. TAKING A
BLEND OF DVORAK INTENSITY ESTIMATES FROM TAFB AND SAB YIELDS AN
INITIAL INTENSITY ESTIMATE OF 80 KT. IRWIN IS CURRENTLY IN AN
ENVIRONMENT OF MODEST EASTERLY SHEAR...BUT IN A COUPLE OF DAYS THIS
SHEAR IS FORECAST TO INCREASE. THEREFORE...THE STRENGTHENING TREND
IS PREDICTED TO END IN 36 TO 48 HOURS...AND THE OFFICIAL INTENSITY
FORECAST IS VERY SIMILAR TO THE LATEST STATISTICAL-DYNAMICAL
GUIDANCE. SOME OF THE DYNAMICAL GUIDANCE INDICATES RESTRENGTHENING
NEAR THE END OF THE FORECAST PERIOD...BUT GIVEN THE UNCERTAINTIES
IN PREDICTING INTENSITY CHANGE AT 5 DAYS...THE OFFICIAL FORECAST
DOES NOT GO WITH THAT SCENARIO.

THE MOTION CONTINUES TO SLOW AND IS NOW ABOUT 295/5. AS THE
MID-LEVEL RIDGE TO THE NORTHEAST OF IRWIN RETREATS TO THE EAST AND
SOUTH...THE TROPICAL CYCLONE IS FORECAST TO TURN TOWARD THE RIGHT
OVER THE NEXT COUPLE OF DAYS. THEREAFTER IRWIN SHOULD BEGIN MOVING
EASTWARD WITHIN A REGION OF BROAD WESTERLY LOW- TO MID-LEVEL FLOW.
SOME OF THE TRACK GUIDANCE SUCH AS THE GFS IS NOT TAKING IRWIN AS
FAR EAST AS PREVIOUSLY. THIS IS CONSISTENT WITH THAT MODEL SHOWING
A MID-TROPOSPHERIC RIDGE BEGINNING TO BUILD TO THE NORTH OF IRWIN
BY DAY 5. THE OFFICIAL TRACK FORECAST GENERALLY LIES BETWEEN THE
GFS AND THE LATEST ECMWF TRACK.

FORECAST POSITIONS AND MAX WINDS

INIT 07/2100Z 14.0N 120.9W 80 KT 90 MPH
12H 08/0600Z 14.2N 121.2W 85 KT 100 MPH
24H 08/1800Z 14.7N 121.2W 90 KT 105 MPH
36H 09/0600Z 14.8N 120.6W 90 KT 105 MPH
48H 09/1800Z 15.0N 119.5W 85 KT 100 MPH
72H 10/1800Z 15.0N 117.0W 75 KT 85 MPH
96H 11/1800Z 15.5N 113.0W 70 KT 80 MPH
120H 12/1800Z 16.5N 109.0W 65 KT 75 MPH

$$
FORECASTER PASCH
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
cycloneye
Storm2k Moderator
Storm2k Moderator
Posts: 112118
Age: 61
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: EPAC: IRWIN - Hurricane

#35 Postby cycloneye » Fri Oct 07, 2011 9:47 pm

8 PM PDT Advirsory

HURRICANE IRWIN DISCUSSION NUMBER 8
NWS NATIONAL HURRICANE CENTER MIAMI FL EP112011
800 PM PDT FRI OCT 07 2011

IRWIN HAS A WELL-DEFINED CENTRAL DENSE OVERCAST THIS EVENING...WITH
CLOUD TOPS COLDER THAN -80C TO THE SOUTHEAST OF THE CENTER. WHILE
THE EYE SEEN EARLIER IN SATELLITE IMAGES IS NOT CURRENTLY
APPARENT...EARLIER MICROWAVE IMAGES SUGGEST IT IS STILL PRESENT
UNDER THE OVERCAST. THE SATELLITE INTENSITY ESTIMATES FROM TAFB AND
SAB HAVE NOT CHANGED...SO THE INITIAL INTENSITY REMAINS 80 KT.
ANALYSES FROM CIMSS AT THE UNIVERSITY OF WISCONSIN SHOW ABOUT 15 KT
OF EASTERLY VERTICAL WIND SHEAR OVER IRWIN...AND THIS IS CAUSING
THE OUTFLOW TO THE EAST TO BE RESTRICTED.

IRWIN CONTINUES TO SLIDE FARTHER WEST-NORTHWESTWARD THAN FORECAST...
WITH THE INITIAL MOTION 295/4. THE TRACK GUIDANCE IS IN GOOD
AGREEMENT THAT THE FORWARD MOTION SHOULD COME TO A HALT LATER
TONIGHT AS A LARGE MID/UPPER-LEVEL TROUGH TO THE NORTH INCREASES
ITS INFLUENCE ON IRWIN. THIS TROUGH IS FORECAST TO CAUSE THE
HURRICANE TO TURN TOWARD THE EAST-NORTHEAST BY 36 HOURS...AND
TOWARD THE EAST AFTER 36 HOURS. THE TRACK GUIDANCE IS IN GOOD
AGREEMENT ON THE DIRECTION OF MOTION...BUT THERE IS SOME SPREAD IN
THE FORWARD SPEED BETWEEN THE FASTER ECMWF AND THE SLOWER
GFS/NOGAPS MODELS. OVERALL...THE NEW GUIDANCE IS A LITTLE SLOWER
THAN EARLIER...AND THUS THE NEW FORECAST TRACK IS A LITTLE SLOWER
THAN THE PREVIOUS TRACK. THE NEW TRACK LIES NEAR THE CENTER OF THE
TRACK GUIDANCE ENVELOPE.

THE DYNAMICAL MODELS FORECAST IRWIN TO ENCOUNTER INCREASED SHEAR AS
IT MAKES ITS EASTWARD TURN IN 24-36 HOURS. THE INTENSITY FORECAST
SHOWS SOME SLOW STRENGTHENING BEFORE THAT TIME...AND SLOW WEAKENING
AFTER THAT TIME. THE NEW INTENSITY FORECAST IS SIMILAR TO THE
SHIPS AND LGEM MODELS FOR THE FIRST 36 HOURS...AND A LITTLE
STRONGER THAN THOSE MODELS AFTER THAT TIME. AS MENTIONED IN THE
PREVIOUS DISCUSSION...THERE IS A POSSIBILITY THAT CONDITIONS COULD
BECOME MORE FAVORABLE FOR STRENGTHENING AT ABOUT 120 HOURS.
HOWEVER...THE EVIDENCE OF THAT OCCURRING NEEDS TO BE STRONGER
BEFORE THE FORECAST CAN SHOW STRENGTHENING AT THAT TIME.

FORECAST POSITIONS AND MAX WINDS

INIT 08/0300Z 14.1N 121.3W 80 KT 90 MPH
12H 08/1200Z 14.4N 121.4W 80 KT 90 MPH
24H 09/0000Z 14.7N 121.1W 85 KT 100 MPH
36H 09/1200Z 14.9N 120.5W 85 KT 100 MPH
48H 10/0000Z 15.0N 119.5W 80 KT 90 MPH
72H 11/0000Z 15.0N 117.0W 70 KT 80 MPH
96H 12/0000Z 15.0N 113.5W 65 KT 75 MPH
120H 13/0000Z 16.5N 109.0W 60 KT 70 MPH

$$
FORECASTER BEVEN
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
Chacor
Category 5
Category 5
Posts: 10231
Joined: Mon Oct 02, 2006 10:43 pm
Location: Singapore

#36 Postby Chacor » Sat Oct 08, 2011 9:37 am

Down to 70 kt in ATCF.
0 likes   

User avatar
cycloneye
Storm2k Moderator
Storm2k Moderator
Posts: 112118
Age: 61
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

#37 Postby cycloneye » Sat Oct 08, 2011 3:41 pm

TROPICAL STORM IRWIN DISCUSSION NUMBER 11
NWS NATIONAL HURRICANE CENTER MIAMI FL EP112011
200 PM PDT SAT OCT 08 2011

THE VERTICAL SHEAR CONTINUES TO ADVERSELY AFFECT IRWIN AND IT
APPEARS THAT THE CYCLONE HAS DROPPED BELOW HURRICANE STRENGTH. AN
INITIAL INTENSITY OF 60 KT IS SUPPORTED BY A BLEND OF THE TAFB AND
SAB SUBJECTIVE DVORAK ESTIMATES...THE CIMSS ADVANCED DVORAK...AND
THE CIMSS AMSU ANALYSIS. A 1242Z AMSU PASS WAS ALSO USEFUL FOR
DIAGNOSING THE WIND RADII FROM THE CIRA SIZE ANALYSIS.

THE TROPICAL STORM IS CURRENTLY EMBEDDED IN A VERY WEAK STEERING
FLOW AND INITIAL MOTION IS SET AT 360 DEGREES AT 1 KT. THE CYCLONE
SHOULD START MOVING OFF TOWARD THE EAST WITH INCREASING FORWARD
SPEED OVER THE NEXT FEW DAYS AS IT RESPONDS TO A SHORT-WAVE TROUGH
DIGGING DOWN OVER THE SOUTHWESTERN UNITED STATES AND NORTHEASTERN
MEXICO. THE INFLUENCE ON THE STEERING BY NEARBY TROPICAL STORM JOVA
IS MINIMAL CURRENTLY...THOUGH MORE OF THE MODEL GUIDANCE THIS
AFTERNOON HAS SUGGESTED SOME FUIJIWHARA INTERACTION AFTER DAY TWO.
THIS HAS THE EFFECT OF A SLIGHTLY SOUTH OF DUE EAST TRACK FOR IRWIN
ON DAY THREE DUE TO A MUTUAL COUNTER-CLOCKWISE ROTATION OF THE TWO
VORTICES. THE FORECAST TRACK IS SIMILAR TO THE MULTI-MODEL
CONSENSUS AND SLIGHTLY FASTER THAN THE PREVIOUS ADVISORY.

THE INTENSITY FORECAST OF IRWIN CONTINUES TO BE QUITE DIFFICULT. THE
EASY PART IS THAT THE SEA SURFACE TEMPERATURES UNDER THE TRACK OF
THE CYCLONE SHOULD REMAIN A VERY WARM 28C. ALSO...THE VERTICAL
SHEAR CURRENTLY PLAGUING THE CYCLONE SHOULD SOMEWHAT ABATE DURING
THE NEXT DAY OR TWO...ALLOWING A MODERATE REBOUND IN THE INTENSITY
TO OCCUR. HOWEVER...BY DAY THREE THE SHEAR MAY AGAIN INCREASE AT
THE SAME TIME THAT THE ATMOSPHERE BECOMES MORE STABLE TO DEEP
CONVECTION. THE GFDL MODEL KEEPS IRWIN A TROPICAL STORM...WHILE THE
HWRF BRINGS IT BACK ALL THE WAY TO A MAJOR HURRICANE. WHILE THE
LGEM/SHIPS MODELS WERE RUN THIS AFTERNOON...BECAUSE OF TECHNICAL
PROBLEMS...THEIR OUTPUT IS BASED UPON THE BAM-MEDIUM TAKING THE
CYCLONE TOO FAR NORTH AND CANNOT BE UTILIZED DIRECTLY. THEREFORE
THE INTENSITY FORECAST IS SLIGHTLY LOWER THAN THE PREVIOUS ADVISORY
DUE TO THE WEAKENED INITIAL STATE...BUT OTHERWISE HAS LITTLE
CHANGE.

FORECAST POSITIONS AND MAX WINDS

INIT 08/2100Z 14.4N 120.9W 60 KT 70 MPH
12H 09/0600Z 14.7N 120.6W 60 KT 70 MPH
24H 09/1800Z 14.9N 119.5W 65 KT 75 MPH
36H 10/0600Z 15.1N 118.4W 70 KT 80 MPH
48H 10/1800Z 15.2N 116.6W 65 KT 75 MPH
72H 11/1800Z 15.0N 114.0W 60 KT 70 MPH
96H 12/1800Z 16.0N 110.0W 55 KT 65 MPH
120H 13/1800Z 19.0N 108.0W 50 KT 60 MPH

$$
FORECASTER LANDSEA/STEWART
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
cycloneye
Storm2k Moderator
Storm2k Moderator
Posts: 112118
Age: 61
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: EPAC: IRWIN - Tropical Storm

#38 Postby cycloneye » Sat Oct 08, 2011 9:52 pm

TROPICAL STORM IRWIN DISCUSSION NUMBER 12
NWS NATIONAL HURRICANE CENTER MIAMI FL EP112011
800 PM PDT SAT OCT 08 2011

THERE HAS BEEN NO SIGNIFICANT CONVECTION NEAR THE CENTER OF IRWIN
FOR THE PAST 12 HOURS AS EASTERLY VERTICAL WIND SHEAR CONTINUES TO
AFFECT THE CYCLONE. THE RATHER UNCERTAIN INITIAL INTENSITY OF 50
KT IS BASED ON A BLEND OF SATELLITE INTENSITY ESTIMATES FROM SAB
AND TAFB...AND IT IS POSSIBLE THIS COULD BE GENEROUS.

THE INITIAL MOTION IS NOW 050/3. WATER VAPOR IMAGERY SHOWS A LARGE
MID/UPPER-LEVEL TROUGH OVER THE WESTERN UNITED STATES AND
NORTHWESTERN MEXICO. THE DYNAMICAL MODELS FORECAST THIS TROUGH TO
MOVE NORTHEASTWARD DURING THE NEXT 72 HOURS AS A SECOND TROUGH
MOVES SOUTHEASTWARD INTO NORTHWESTERN MEXICO. THIS TROUGH IS
FORECAST TO BECOME A CUT-OFF LOW OVER THE PACIFIC WEST OF MEXICO BY
120 HOURS. THIS EVOLUTION IS FORECAST TO STEER IRWIN EAST-
NORTHEASTWARD TO EASTWARD DURING THE NEXT 72 HOURS. AFTER THAT
TIME...THERE IS SIGNIFICANT SPREAD IN THE MODEL GUIDANCE. THE GFS
SHOW IRWIN RESPONDING STRONGLY TO THE NEW TROUGH AND TURNING
NORTHWARD SOUTH OF BAJA CALIFORNIA. THE GFDL SHOWS A CONTINUED
EASTWARD MOTION...WITH THE REMAINDER OF THE DYNAMICAL MODELS SPREAD
BETWEEN THESE EXTREMES. OVERALL...THE GUIDANCE IS A LITTLE FASTER
AND A LITTLE FARTHER TO THE EAST THAN ON THE PREVIOUS ADVISORY.
THE NEW FORECAST TRACK CALLS FOR A GRADUAL TURN TOWARD THE
NORTH-NORTHEAST AFTER 72 HOURS IN BEST AGREEMENT WITH THE CANADIAN
MODEL. THE NEW TRACK LIES TO THE LEFT OF THE CONSENSUS MODEL.

THE INTENSITY FORECAST IS BASED ON THE PREMISE THAT CONVECTION
RE-DEVELOPS NEAR THE CENTER OF IRWIN AND THAT THE CYCLONE DOES NOT
DECAY TO A REMNANT LOW. THE LATEST DYNAMICAL MODEL RUNS SUGGEST
THAT MODERATE EASTERLY SHEAR MAY CONTINUE FOR AS LONG AS 72 HOURS
BEFORE CONDITIONS BECOME MORE FAVORABLE FOR STRENGTHENING.
INDEED...THE GFDL AND HWRF MODELS SHOW LITTLE CHANGE IN STRENGTH
FOR 72 HOURS OR SO...FOLLOWED BY INTENSIFICATION. THE INTENSITY
FORECAST IS SIGNIFICANTLY CHANGED FROM THAT OF THE PREVIOUS
ADVISORY...CALLING FOR IRWIN TO WEAKEN A LITTLE MORE BEFORE
MAINTAINING AN INTENSITY NEAR 45 KT THROUGH 72 HOURS. AFTER THAT
TIME...WARMER SEA SURFACE TEMPERATURES AND DECREASED SHEAR MAY
ALLOW SOME INTENSIFICATION. THE NEW INTENSITY FORECAST SHOWS
THIS...BUT IS NOT AS STRONG AS THE GFDL AND HWRF MODELS.

FORECAST POSITIONS AND MAX WINDS

INIT 09/0300Z 14.7N 120.3W 50 KT 60 MPH
12H 09/1200Z 15.0N 119.7W 45 KT 50 MPH
24H 10/0000Z 15.3N 118.5W 45 KT 50 MPH
36H 10/1200Z 15.5N 117.3W 45 KT 50 MPH
48H 11/0000Z 15.6N 115.8W 45 KT 50 MPH
72H 12/0000Z 15.5N 113.0W 50 KT 60 MPH
96H 13/0000Z 17.0N 109.0W 55 KT 65 MPH
120H 14/0000Z 20.0N 107.5W 60 KT 70 MPH

$$
FORECASTER BEVEN
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
somethingfunny
ChatStaff
ChatStaff
Posts: 3688
Age: 30
Joined: Thu May 31, 2007 10:30 pm
Location: Eastern Dallas County, TX

#39 Postby somethingfunny » Sun Oct 09, 2011 2:26 am

This thing is toast. Jova sliced it open.
0 likes   
I am not a meteorologist, and any posts made by me are not official forecasts or to be used as such. These posts are just my opinions and are probably silly opinions.

Click here to join us in Storm2k.org's official (and operational!) chatroom!

Rules for the Storm2k.org chatroom

bexar
Tropical Storm
Tropical Storm
Posts: 182
Joined: Sat Aug 20, 2011 11:23 am

#40 Postby bexar » Sun Oct 09, 2011 3:00 am

Irwin looks like a mess, doesn't look like a cyclone anymore
0 likes   


Return to “2011”

Who is online

Users browsing this forum: No registered users and 1 guest