Major Hurricane Irene

[weatherobsuk]

Bahamas capital Nassau has a pop of 300,000 not counting tourists, hoteliers, etc. All of which now have 48hr for their travel companies to decide what to do with them, unless they themselves evac through whatever means possible. Unlikely any mass-exodus will be happening though as the Bahaman's simply ride it out by sheltering within the innermost parts of the hotels on the islands. The hotels of which are barely above sea level, so it's going to be a rough one for anyone braving it out.

The animated wave heights aren't too pleasant to look at, knowing how many are soon going to be in the path.

http://polar.ncep.noaa.gov/waves/latest_run/wna_ecg.anim.gif

[knocker]

WTNT44 KNHC 230838

TCDAT4

HURRICANE IRENE DISCUSSION NUMBER 12

NWS NATIONAL HURRICANE CENTER MIAMI FL AL092011

500 AM EDT TUE AUG 23 2011

SMOOTHING THROUGH ALL OF THE AIRCRAFT FIXES SINCE IRENE MOVED OFF

THE COAST OF PUERTO RICO MORE THAN 18 HOURS AGO YIELDS A LONG TERM

MOTION OF 295/10 KT...WHICH IS USED FOR THIS ADVISORY. THERE IS NO

SIGNIFICANT CHANGE TO THE PREVIOUS FORECAST TRACK REASONING. THE

23/00Z G-IV JET AIRCRAFT AND AIR FORCE C-130 DROPSONDE DATA APPEAR

TO HAVE SETTLED DOWN THE MODELS...AND THERE IS CONSIDERABLY LESS

DIFFERENCE AMONG THE VARIOUS MODEL SOLUTIONS NOW. THE OVERWHELMING

CONSENSUS IS THAT IRENE WILL GRADUALLY TURN NORTHWESTWARD OVER THE

NEXT 2-3 DAYS AND THEN MOVE NORTHWARD THROUGH A DEVELOPING BREAK IN

THE SUBTROPICAL RIDGE OVER THE SOUTHEASTERN UNITED STATES. THE

OFFICIAL FORECAST TRACK IS SIMILAR TO THE PREVIOUS ADVISORY AND

LIES VERY CLOSE TO CONSENSUS MODELS TVCN AND TVCA.

AN EARLIER RECON FLIGHT INDICATED THE PRESSURE HAD ONLY FALLEN BY 2

MB DOWN TO 978 MB...AND THE OVERALL APPEARANCE IN SATELLITE IMAGERY

HAS CHANGED LITTLE SINCE THE PREVIOUS ADVISORY. AS A RESULT...THE

INITIAL INTENSITY IS BEING HELD AT 85 KT...WHICH COULD BE GENEROUS.

IRENE IS FORECAST TO REMAIN IN A RELATIVELY LOW VERTICAL WIND SHEAR

ENVIRONMENT AND OVER SSTS NEAR 30C. THAT COMBINATION...ALONG WITH

EXPANDING OUTFLOW IN ALL QUADRANTS...SHOULD ALLOW FOR IRENE TO

BECOME A MAJOR HURRICANE WITHIN THE NEXT 24 HOURS ONCE THE CYCLONE

CLEARS THE EFFECTS OF HISPANIOLA...AND PROBABLY MAINTAIN MAJOR

HURRICANE STATUS THROUGHOUT THE REMAINDER OF THE 5-DAY FORECAST

PERIOD. THE INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY

AND CLOSELY FOLLOWS A BLEND OF THE HWRF AND GFDL MODEL INTENSITY

FORECASTS...AND CONVERSION OF THE SURFACE PRESSURES DEPICTED IN THE

GFS AND ECMWF MODELS.

WIND RADII WERE EXPANDED BASED ON A BLEND OF RECON FLIGHT-LEVEL

WINDS...SFMR WINDS...AND SURFACE OBSERVATIONS.

IRENE IS FORECAST TO BECOME A LARGER THAN AVERAGE HURRICANE. IT IS

IMPORTANT TO REMIND USERS NOT TO FOCUS ON THE EXACT FORECAST

TRACK...ESPECIALLY AT DAYS 4 AND 5...SINCE THE MOST RECENT 5-YEAR

AVERAGE ERRORS AT THOSE FORECAST TIMES ARE 200 AND 250 MILES...

RESPECTIVELY.

FORECAST POSITIONS AND MAX WINDS

INIT 23/0900Z 20.3N 70.1W 85 KT 100 MPH

12H 23/1800Z 20.9N 71.5W 95 KT 110 MPH

24H 24/0600Z 21.7N 73.3W 105 KT 120 MPH

36H 24/1800Z 22.9N 74.9W 110 KT 125 MPH

48H 25/0600Z 24.3N 76.2W 110 KT 125 MPH

72H 26/0600Z 28.0N 78.0W 115 KT 135 MPH

96H 27/0600Z 31.5N 78.3W 105 KT 120 MPH

120H 28/0600Z 35.0N 78.0W 100 KT 115 MPH...INLAND

$$

FORECASTER STEWART

A quick shufty on Google.

[AderynCoch]

This is becoming a very large hurricane with extended wind radii in all directions. For this reason I think she will only reach Cat 3 as the internal dynamics of large hurricanes make it harder for them to gain and retain Cat 4/5 status.

Larger hurricanes do indeed take longer to organise themselves and are less prone to rapid fluctuations (unless there's an unusually warm pool of water, like the Gulf Loop Current), so we're probably looking at gradual rather than rapid intensification in the short term. Never say never though.

There is a patch of the Gulf Stream at 30-32C just off the Atlantic coast of Florida/Georgia, which Irene is later forecast to cross.

[AderynCoch]

Oh yeah, the link:

http://www.wundergro...index_region=at

[mezzacyclone]

mmm, the plot thickens it seems.

The upper level trough is quite active and will be enhanced further with another dropping down from west of the great lakes to the east coast come fri/sat which Irene will come up against so east path favored again and possible landfall further north? dare i say it? if at all?

[karyo]

mmm, the plot thickens it seems.

The upper level trough is quite active and will be enhanced further with another dropping down from west of the great lakes to the east coast come fri/sat which Irene will come up against so east path favored again and possible landfall further north? dare i say it? if at all?

Watch the models take the path further east in the following days and eventually keep it in the Atlantic.

It doesn't look likely that the UK is going to get the remnants either as an area of high pressure is likely to develop over us from this weekend.

Karyo

Edited August 23, 2011 by karyo

[Iceberg]

You might be right Karyo but none of the models keep her out in the atlantic not hitting the US at all. It might happen but I would like to see some evidence for it first. ATM the model consensus is still an east coast hit.

Irene is still intensifying then as recon have just found pressure to 976mb so far in the SE quad and winds to 60kts which is surprisingly high given this is the quad most effected by the clossness of land.

[Iceberg]

Just finishing it's first pass from SE to NW pressure of 975mb and surface winds to 74kts

[karyo]

You might be right Karyo but none of the models keep her out in the atlantic not hitting the US at all. It might happen but I would like to see some evidence for it first. ATM the model consensus is still an east coast hit.

Irene is still intensifying then as recon have just found pressure to 976mb so far in the SE quad and winds to 60kts which is surprisingly high given this is the quad most effected by the clossness of land.

Based on what the models are showing at the moment, it is realistic to expect some sort of landfall on the east coast. However, my belief that it won't, is based on the shift eastwards that we've seen in the last 24 hours and this is quite often what happens when a hurricane is projected to hit the east coast.

Karyo

[Iceberg]

The centre is quite displaced under the convection atm and Vortex data indicates that the eye is open in the SW and that the SE is really quite weak.

Outflow is also not as good as it was particularly in the west. It might need a further 24 hrs before strengthening can really resume.

the next 24 I think really will start to become critical for paths, intensity etc a sharp turn northwards should be occuring during that time.

[Polar Bear]

updated public advsiory out and the bahamas have a tropical storm watch instead...pheew for them

000

WTNT34 KNHC 231450

TCPAT4

BULLETIN

HURRICANE IRENE ADVISORY NUMBER 13

NWS NATIONAL HURRICANE CENTER MIAMI FL AL092011

1100 AM EDT TUE AUG 23 2011

...IRENE APPROACHING THE TURKS AND CAICOS ISLANDS...

SUMMARY OF 1100 AM EDT...1500 UTC...INFORMATION

-----------------------------------------------

LOCATION...20.5N 71.0W

ABOUT 70 MI...110 KM S OF GRAND TURK ISLAND

ABOUT 50 MI...85 KM NNW OF PUERTO PLATA DOMINICAN REPUBLIC

MAXIMUM SUSTAINED WINDS...100 MPH...160 KM/H

PRESENT MOVEMENT...WNW OR 295 DEGREES AT 12 MPH...19 KM/H

MINIMUM CENTRAL PRESSURE...980 MB...28.94 INCHES

WATCHES AND WARNINGS

--------------------

CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY...

THE GOVERNMENT OF THE BAHAMAS HAS CHANGED THE HURRICANE WATCH FOR

THE NORTHWESTERN BAHAMAS TO A HURRICANE WARNING.

THE GOVERNMENT OF THE DOMINICAN REPUBLIC HAS CHANGED THE HURRICANE

WARNING ALONG THE NORTH COAST OF THE DOMINICAN REPUBLIC TO A

TROPICAL STORM WARNING.

THE TROPICAL STORM WARNING FOR HAITI SOUTH OF LE MOLE ST.

NICHOLAS HAS BEEN DISCONTINUED.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A HURRICANE WARNING IS IN EFFECT FOR...

* TURKS AND CAICOS ISLANDS

* THE SOUTHEASTERN...CENTRAL...AND NORTHWESTERN BAHAMAS

A HURRICANE WATCH IS IN EFFECT FOR...

* NORTH COAST OF HAITI FROM LE MOLE ST. NICHOLAS EASTWARD TO THE

DOMINICAN REPUBLIC BORDER

A TROPICAL STORM WARNING IS IN EFFECT FOR...

* NORTH COAST OF THE DOMINICAN REPUBLIC FROM CABO ENGANO WESTWARD TO

THE HAITI BORDER

* NORTH COAST OF HAITI FROM LE MOLE ST. NICHOLAS EASTWARD TO THE

DOMINICAN REPUBLIC BORDER

FOR STORM INFORMATION SPECIFIC TO YOUR AREA...PLEASE MONITOR

PRODUCTS ISSUED BY YOUR NATIONAL METEOROLOGICAL SERVICE.

DISCUSSION AND 48-HOUR OUTLOOK

------------------------------

AT 1100 AM EDT...1500 UTC...THE CENTER OF HURRICANE IRENE WAS

LOCATED BY AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT NEAR

LATITUDE 20.5 NORTH...LONGITUDE 71.0 WEST. IRENE IS MOVING TOWARD

THE WEST-NORTHWEST NEAR 12 MPH...19 KM/H. THIS GENERAL MOTION IS

EXPECTED TO CONTINUE THROUGH TONIGHT...FOLLOWED BY A TURN TOWARD

THE NORTHWEST ON WEDNESDAY. ON THE FORECAST TRACK...THE CORE OF

IRENE WILL MOVE NEAR OR OVER THE TURKS AND CAICOS ISLANDS AND THE

SOUTHEASTERN BAHAMAS TONIGHT...BE NEAR THE CENTRAL BAHAMAS EARLY

WEDNESDAY...AND NEAR OR OVER THE NORTHWESTERN BAHAMAS ON THURSDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR 100 MPH...160 KM/H...WITH HIGHER

GUSTS. IRENE IS A CATEGORY TWO HURRICANE ON THE SAFFIR-SIMPSON

HURRICANE WIND SCALE. STRENGTHENING IS FORECAST DURING THE NEXT

48 HOURS...AND IRENE COULD BECOME A MAJOR HURRICANE BY WEDNESDAY.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 50 MILES...85 KM...FROM

THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 205

MILES...335 KM.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 980 MB...28.94 INCHES.

HAZARDS AFFECTING LAND

----------------------

WIND...TROPICAL STORM CONDITIONS WILL CONTINUE OVER NORTHERN

PORTIONS OF THE DOMINICAN REPUBLIC THROUGH THIS AFTERNOON. TROPICAL

STORM CONDITIONS ARE SPREADING OVER THE SOUTHEASTERN BAHAMAS AND

THE TURKS AND CAICOS ISLANDS WITH HURRICANE CONDITIONS EXPECTED

BY THIS AFTERNOON AND EVENING. TROPICAL STORM CONDITIONS ARE

FORECAST TO REACH THE CENTRAL BAHAMAS LATE TONIGHT WITH HURRICANE

CONDITIONS EXPECTED BY WEDNESDAY. TROPICAL STORM CONDITIONS ARE

EXPECTED IN THE NORTHWESTERN BAHAMAS BY LATE WEDNESDAY...WITH

HURRICANE CONDITIONS EXPECTED BY THURSDAY.

STORM SURGE...AN EXTREMELY DANGEROUS STORM SURGE WILL RAISE WATER

LEVELS BY AS MUCH AS 9 TO 13 FEET ABOVE NORMAL TIDE LEVELS OVER THE

BAHAMAS AND THE TURKS AND CAICOS ISLANDS...NEAR AND TO THE NORTH OF

THE CENTER OF IRENE. A STORM SURGE WILL ALSO RAISE WATER LEVELS BY

AS MUCH AS 2 TO 4 FEET ABOVE NORMAL TIDE LEVELS ALONG THE NORTH

COAST OF HAITI AND THE ENTIRE COAST OF THE DOMINICAN REPUBLIC. NEAR

THE COAST...THE SURGE WILL BE ACCOMPANIED BY LARGE AND DANGEROUS

WAVES.

RAINFALL...IRENE IS EXPECTED TO PRODUCE ADDITIONAL RAINFALL

ACCUMULATIONS OF 1 TO 3 INCHES ACROSS PUERTO RICO. RAINFALL

AMOUNTS OF 4 TO 8 INCHES ARE EXPECTED OVER NORTHERN HISPANIOLA...

WITH ISOLATED MAXIMUM AMOUNTS OF UP TO 15 INCHES POSSIBLE OVER

HIGHER TERRAIN. THESE RAINS COULD CAUSE LIFE-THREATENING FLASH

FLOODS AND MUDSLIDES IN AREAS OF STEEP TERRAIN. RAINFALL

ACCUMULATIONS OF 5 TO 10 INCHES ARE EXPECTED IN THE SOUTHEASTERN

AND CENTRAL BAHAMAS...AND THE TURKS AND CAICOS ISLANDS.

NEXT ADVISORY

-------------

NEXT INTERMEDIATE ADVISORY...200 PM EDT.

NEXT COMPLETE ADVISORY...500 PM EDT.

$$

FORECASTER BROWN/BLAKE

[Iceberg]

The eye is really clearing now and we might get some nice picies in the next few hrs.

[Iceberg]

Recon have just search the eye and got the below, lowest pressure of 974.4mb (all below 980), so quite a bit lower than the 980mb forecast from the NHC just 1 hr ago (thought it strange that they went for pressure that high ! )

154900 2036N 07115W 6921 03037 9785 +149 +095 355047 048 050 002 03154930 2036N 07113W 6914 03032 9774 +146 +107 350037 042 038 000 03155000 2036N 07111W 6918 03019 9763 +148 +097 357027 030 033 000 00155030 2036N 07109W 6916 03012 9752 +150 +095 009018 023 028 000 00155100 2035N 07108W 6909 03018 9748 +151 +099 359009 010 022 001 03155130 2035N 07106W 6916 03009 9751 +148 +098 079008 011 024 000 03155200 2035N 07104W 6913 03009 9750 +145 +099 126012 015 024 000 00155230 2036N 07102W 6913 03011 9754 +143 +098 140018 018 033 001 03155300 2036N 07100W 6916 03013 9766 +135 +103 175025 027 035 002 03155330 2036N 07058W 6914 03022 9784 +129 +110 171029 035 /// /// 03155400 2034N 07058W 6923 03018 9797 +118 //// 166034 037 /// /// 05155430 2034N 07100W 6914 03016 9774 +128 +118 185026 030 026 000 03155500 2035N 07102W 6916 03010 9761 +135 +111 173015 020 030 000 00155530 2035N 07104W 6912 03013 9764 +135 +104 135009 011 026 000 03155600 2035N 07106W 6915 03013 9757 +143 +099 048006 011 023 000 03155630 2034N 07107W 6914 03014 9762 +140 +104 009014 016 023 001 03155700 2034N 07109W 6908 03025 9760 +147 +096 021021 024 /// /// 03155730 2036N 07109W 6920 03011 9750 +155 +092 024020 023 /// /// 03155800 2036N 07107W 6916 03009 9744 +152 +098 063011 015 024 000 00155830 2036N 07105W 6912 03014 9754 +144 +101 119012 014 025 000 00

Edited August 23, 2011 by Iceberg

[Iceberg]

ATM Irene is travelling west and not going far enough north to follow the near path. With the eye visible on Visual we can much more easily track direction.

Looking at the below she is very lopsided excellent on the east side, very poor on the west.

[mezzacyclone]

If anyones confused over Ice`s raw data here`s the run with the lowest air pressure reading >

time=15:58:00Z

Coordinates=20.600N 71.117

Aircraft Static Air Pressure=691.2 mb

AircraftGeopotential Height=9,888 feet

ExtrapolatedSurface Pressure=974.4 mb

Flight Level Wind (30 sec. Avg.)=From 63° at 11 knots (From the ENE at ~ 12.6 mph)

Air Temp.=15.2°C(~ 59.4°F)

Dew Point=9.8°C(~ 49.6°F)

Peak (10 sec. Avg.)Flight Level Wind=15 knots(~ 17.2 mph)

SFMR Peak (10s Avg.) Sfc. Wind=24 knots(~ 27.6 mph)

SFMR rain rate=0 mm/hr(~ 0 in/hr)

Estimated Surface Wind (30 sec. Avg.)Using Estimated Reduction Factor=17.6 knots (~ 20.2 mph)

Peak Wind at Flight Level to Est. Surface Reduction Factor=160.0%

eyes closed again on the 15:45 after we briefly saw signs of a clearing?

http://www.ssd.noaa.gov/goes/east/watl/ir4-l.jpg

Edited August 23, 2011 by mezzacyclone

[Iceberg]

I think the eye still looks OK on floater visual or RGB.

GFS 12Z is out and is a little bit further westward, but essentially very similar to the 06Z.

[AderynCoch]

updated public advsiory out and the bahamas have a tropical storm watch instead...pheew for them

All of the Bahamas are under a hurricane warning, as per the advisory you posted! The Turks & Caicos Islands are also in for a rough time, but it shouldn't be as bad as it was with Ike (Irene shouldn't be as strong as Ike was when passing through).

Visible eye finally starting to appear on satellite: http://www.ssd.noaa.gov/goes/flt/t2/flash-vis.html. Irene's circulation is still too close to Hispaniola to avoid disruption of convection on the south side of the storm.

[mezzacyclone]

I think the eye still looks OK on floater visual or RGB.

GFS 12Z is out and is a little bit further westward, but essentially very similar to the 06Z.

true, my bad

http://www.ssd.noaa..../catl/rgb-l.jpg

clearer one here >

[Cookie]

thanks for all the updates guys really Appreciated!

eye trying to form!

[AderynCoch]

As for possible US landfall, given the continuing eastward trend of the track forecasts, the eye might just miss the Outer Banks (like Earl last year) but hurricane conditions are still likely.

Here's how the NHC cone of uncertainty has changed since advisories were started:

http://www.nhc.noaa....9/loop_5W.shtml

Edited August 23, 2011 by AderynCoch

[SMU]

The southern quadrent looks week at the moment=- with the land interaction we are not getting that classic spiral shape- so intensification will be slow until it curves away from the larger islands-

Once it does then the enviroment will be more fabvourable-

Looking at the track it could be a NE dream for cape cod chasers-

S

[Cookie]

As for possible US landfall, given the continuing eastward trend of the track forecasts, the eye might just miss the Outer Banks (like Earl last year) but hurricane conditions are still likely.

Here's how the NHC cone of uncertainty has changed since advisories were started:

http://www.nhc.noaa....9/loop_5W.shtml

some very good advice I found on another site.

In the first place, the cone should not be the determinant as to whether anyone should make preparations for possible impact. The cone is merely a region that defines the 5-year 67th percentile track error. This means that of all the NHC forecasts over the past 5 years (2006-2010), the CENTER of the storms stayed within that cone area 67% of the time.

The cone IS NOT a good indicator of the potential impact area from a hurricane, meaning you're not considered "safe" if you're outside the cone. Even if a hurricane's center tracks right down the middle of the cone, its tropical storm force winds can extend well outside the cone. Same goes for the hurricane winds at times. Your location could be outside the cone and still receive hurricane conditions and a major tidal increase, as was the case with the Louisiana coast with Ike's cone.

So don't judge yourself safe if you're outside the cone. Pay attention to what the local NWS office and the NHC are saying regarding potential impact and make your decisions accordingly.

image taken earlier today from space!

[Iceberg]

Cheap flight to NYC might be an easy option for anyone wanting a few days away with a hurricane thrown in.

HWRF and GFS both going for the NC hit followed by Long Beach.

Just a quick add, incase people were looking at the aggressive models and then at how she is now and discounting them, Irene was never forecast to be much more than she is now. Infact IMO for a storm that has had it's southern areas cut off this long close to land to still be in the state it is, is frankly very very worrying indeed.

The really strong intensification isn't progged to happen until she leaves the Bahamas.

Edited August 23, 2011 by Iceberg

[Iceberg]

GFDL 12Z is out and shows the same as the others NC hit and then 100kt+ winds into NYC and Long Beach.

[Iceberg]

ECM take a slightly more easterly path hitting NC and then hugging the coast and upto NYC at a CAT 4. That's going to hurt.