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Somerset Squall

Major Hurricane Neki

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Invest 94E, that became invest 96C, has become much better organised, with convection persisting over a well defined LLC, thus the system has been upgraded to a 25kt tropical depression. Water are warm beneath the depression, and shear is moderate, so some slow intensification is forecast. CPHC forecst 03C to strengthen into a hurricane, but rapid intensification seems unlikely due to the moderate shear. 03C is well south of the Hawaiian Islands and as it is expected to move northwestwards over the next few days, 03C doesn't seem a risk to land as yet.

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03C continues to become better organised and has been upgraded to Tropical Storm Neki, with intensity now at 35kts. Neki is a large storm with good central convection and improved banding. Shear is low, waters are around 29C and will remain so on the forecast track. As a result, Neki will intensify into a hurricane in a couple days time. In fact, theres every possibility of Neki becoming a major hurricane as the environment is not expected to deteriorate. Neki will be approaching Johnston Atoll in a couple days (which was last hit by Ioke in 2006) so needs to be watched. CPHC mention the possibilty of rapid intensification and this can't be ruled out given the environment.

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Neki's satellite appearance has improved markedly over the past 18hrs. Neki had a large, sprawled appearance last night with little central convection. The storm has now become more compacted with a central dense overcast feature now firmly established. Intensity has increased to 55kts, and Neki could become a hurricane later today.

Neki is still moving northwestwards, but in a few days time, the track should bend to the west as a new ridge builds to the north of the storm. Neki will not effect the island of Hawaii, but may come very close to Johnson Island as a hurricane, therefore a hurricane watch has been issued.

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Neki has continued to intensify and is now a 60kt tropical storm. Based on the recnet appearance of an eye in satellite imagery, Neki is probably nearing hurricane strength. Neki's track forecast hasn't changed; a northwestward track is expected followed by slowing and a turn to the west. Conditions are favourable over the next few days with low shear and warm sea temps, which will allow Neki to strengthen further. Neki is forecast to become a major hurricane before shear increases after 72hrs which should induce weakening.

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Neki has just literally been upgraded to a 65kt hurricane:

HURRICANE NEKI INTERMEDIATE ADVISORY NUMBER 9A

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI CP032009

200 PM HST TUE OCT 20 2009

...NEKI STRENGTHENS TO A HURRICANE AS IT CONTINUES TO TRACK

NORTHWESTWARD FAR SOUTHWEST OF THE MAIN HAWAIIAN ISLANDS...

A HURRICANE WATCH CONTINUES FOR JOHNSTON ISLAND. A HURRICANE WATCH

MEANS THAT HURRICANE CONDITIONS ARE POSSIBLE IN THE WATCH AREA

WITHIN THE NEXT 48 HOURS.

AT 200 PM HST...0000 UTC...THE CENTER OF HURRICANE NEKI WAS

LOCATED NEAR LATITUDE 14.9 NORTH...LONGITUDE 164.8 WEST OR ABOUT

630 MILES SOUTHWEST OF HONOLULU HAWAII AND ABOUT 340 MILES

EAST-SOUTHEAST OF JOHNSTON ISLAND.

NEKI IS MOVING TOWARD THE NORTHWEST NEAR 15 MPH. NEKI WILL

GRADUALLY TURN TO THE NORTH NORTHWEST AND DECREASE ITS FORWARD

MOTION DURING THE NEXT 48 HOURS.

MAXIMUM SUSTAINED WINDS ARE NEAR 75 MPH WITH HIGHER GUSTS. NEKI IS

FORECAST TO CONTINUE INTENSIFYING THROUGH 48 HOURS.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 90 MILES FROM THE

CENTER.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 996 MB...29.41 INCHES.

ANYONE NEAR JOHNSTON ISLAND IS URGED TO CLOSELY MONITOR THE

PROGRESS OF NEKI. A TROPICAL STORM OR HURRICANE WARNING MAY BE

ISSUED FOR JOHNSTON ISLAND LATER TODAY.

...SUMMARY OF 200 PM HST INFORMATION...

LOCATION...14.9N 164.8W

MAXIMUM SUSTAINED WINDS...77 MPH

PRESENT MOVEMENT...NORTHWEST OR 320 DEGREES AT 15 MPH

MINIMUM CENTRAL PRESSURE...996 MB

THE NEXT ADVISORY WILL BE ISSUED BY THE CENTRAL PACIFIC HURRICANE

CENTER AT 500 PM HST.

$$

FORECASTER WROE

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Neki continues to quickly intensify, and intensity is now at 75kts. Neki has developed a small eye which has recently become cloud obscured. This could mean that further intensification will be slower, but if that eye clears out then Neki could rapidly become a major hurricane. A lot of uncertainties therefore, on just how strong Neki will get.

The track forecast has changed too. It now appears that significant ridging will not build in to the north of Neki due to a series of troughs maintaing the weakness in any ridging trying to form to the north. Therefore, Neki is expected to continue northwestwards for the next day or so before recurving to the north and then northeast. This motion will bring Neki over colder waters and higher shear beyong 48hrs whcih should initiate weakening.

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wouldn't be surprised if this a major sooner rather then later.

20091021.1830.goes11.x.vis1km.03CNEKI.90kts-975mb-166N-1664W.100pc.jpg

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Indeed, Neki is now a 100kt, cat 3 major hurricane. The eye has become really impressive over the last few hours, with a symmetrical central dense overcast flanking it. I estimate a peak intensity of around 120kts before the shear increases and waters cool. Neki has around 24-36hrs to intensify.

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its going to start weakening soon, but another terrific looking hurricane

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Well, Neki didn't strengthen quite as much as I thought, and peaked at 105kts. Neki has since weakened slightly to 100kts. Southwesterly shear increased sooner than expected and is negatively impacting the hurricane by displacing convection to the northeast of the eye and eroding convection in the southwestern quadrant. Neki is also moving north-northeastwards now and is expected to turn towards the northeast soon towards the weakness in the subtropical ridge. This will take Neki over decreasing sea temps and continued high shear, accelerating the weakening trend. Neki will take a while to spin down as it retains and intense inner core at present.

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Passed her peak now by the looks of things

PHFO 222046

TCDCP2

HURRICANE NEKI DISCUSSION NUMBER 17

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI CP032009

1100 AM HST THU OCT 22 2009

HURRICANE NEKI IS SLOWLY WEAKENING AS STRONG SOUTHWESTERLY SHEAR

CONTINUES TO IMPACT THE SYSTEM. FIXES FROM CPHC...JTWC...AND SAB

ALL CAME IN WITH CI VALUES OF 5.0 WHICH SETS THE INITIAL INTENSITY

AT 90 KT.

THE INITIAL POSITION HAS BEEN SHIFTED TO THE LEFT WITH THE SYSTEM

MOVING A BIT SLOWER THAN THE PREVIOUS FORECAST. THIS WAS MAINLY DUE

TO A RECENT SSMIS PASS AND EARLY MORNING VISIBLE IMAGERY. MODELS

ARE IN GOOD AGREEMENT WITH A CONTINUED NORTH-NORTHEAST MOTION IN

THE SHORT TERM THEN A TURN MORE TO THE NORTHEAST WITH GRADUAL

ACCELERATION EXPECTED AS THE SYSTEM INTERACTS WITH AN ENCROACHING

FRONT AND ITS ASSOCIATED UPPER LEVEL TROUGH. THE LATEST FORECAST

TRACK IS PRETTY MUCH DOWN THE MIDDLE OF THE GUIDANCE BUT SLIGHTLY

TO THE LEFT OF THE PREVIOUS FORECAST MAINLY DUE TO THE WESTWARD

SHIFT OF THE INITIAL POSITION.

NEKI WILL REMAIN OVER 26 C OR WARMER WATER THROUGH 48 HOURS...THEN

MOVE ACROSS COOLER WATERS THROUGH THE REST OF ITS FORECAST TRACK.

THE LATEST UW-CIMSS VERTICAL WIND SHEAR PRODUCT SHOWS SOUTHWEST

SHEAR OF 24 KT. THIS STRONG SHEAR IS EXPECTED TO CONTINUE FOR THE

NEXT SEVERAL DAYS AND WILL BE THE PRIMARY KEY IN THE WEAKENING

PROCESS. NEKI IS FORECAST TO WEAKEN TO A TROPICAL STORM BY 72

HOURS...THEN TO A DEPRESSION BY 120 HOURS WHEN THE SYSTEM WILL

LIKELY BE CLASSIFIED AS EXTRATROPICAL.

ON ITS CURRENT TRACK...NEKI WILL BE IMPACTING THE PAPAHANAUMOKUAKEA

NATIONAL MONUMENT NEAR FRENCH FRIGATE SHOALS TONIGHT AND

FRIDAY...AND A HURRICANE WARNING REMAINS FOR THE MONUMENT FROM

NIHOA ISLAND TO MARO REEF. LARGE SWELLS FROM THE SOUTH WILL BUILD

AND CONDITIONS WILL CONTINUE TO DETERIORATE ACROSS PORTIONS OF THE

WARNING AREA TODAY AND TONIGHT...WITH SEAS GREATER THAN 20 FT AND

SURF UP 25 FT EXPECTED.

FORECAST POSITIONS AND MAX WINDS

INITIAL 22/2100Z 20.8N 166.3W 90 KT

12HR VT 23/0600Z 21.8N 166.1W 85 KT

24HR VT 23/1800Z 23.4N 165.7W 80 KT

36HR VT 24/0600Z 25.0N 164.8W 75 KT

48HR VT 24/1800Z 27.0N 163.6W 65 KT

72HR VT 25/1800Z 31.0N 160.7W 55 KT

96HR VT 26/1800Z 35.6N 156.8W 40 KT

120HR VT 27/1800Z 40.9N 151.9W 30 KT...EXTRATROPICAL

$$

FORECASTER BURKE

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Neki has weakened rapidly today, and has lost the majority of it's convection due to persistant high shear and cooling sea surface temperatures. Intensity has been reduced to 60kts, therefore Neki is no longer a hurricane. Further weakening is expected as Neki accelerates northeastward out of the tropics, and extratropical transition will begin in around 48hrs IMO, unless dissipation occurs first.

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FORECAST POSITIONS AND MAX WINDS

INITIAL 24/2100Z 24.8N 163.9W 50 KT

12HR VT 25/0600Z 25.6N 163.7W 45 KT

24HR VT 25/1800Z 26.6N 163.7W 45 KT

36HR VT 26/0600Z 27.8N 163.9W 40 KT

48HR VT 26/1800Z 30.4N 163.9W 35 KT...BECOMING EXTRATROPICAL

72HR VT 27/1800Z 39.6N 159.3W 35 KT...EXTRATROPICAL

$$

FORECASTER KODAMA

20091024.2315.goes11.x.vis1km_high.03CNEKI.50kts-1001mb-245N-1640W.88pc.jpg

20091024.1854.f16.x.91hw.03CNEKI.50kts-1001mb-245N-1640W.65pc.jpg

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she did hold her self for a wee while despite being really exposed

2009CP03_1KMSRVIS_200910252300.GIF

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TROPICAL STORM NEKI DISCUSSION NUMBER 31

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI CP032009

1100 PM HST SUN OCT 25 2009

THE LOW LEVEL CIRCULATION CENTER OF NEKI REMAINS TUCKED UNDER THE

WEST SIDE OF A PERSISTENT CONVECTIVE CLUSTER. THE FIX AGENCIES

REPORT A CI OF 2.5 BASED ON A SHEAR PATTERN...WITH LITTLE OR NO

CHANGE IN INTENSITY OVER THE LAST 24 HOURS. THE INITIAL INTENSITY

OF NEKI HAS BEEN LOWERED TO 35 KT IN AGREEMENT WITH THE FIX DATA.

NEKI IS LOCATED ON THE SOUTHWEST END OF A LARGE SUBTROPICAL RIDGE

AND SOUTHEAST OF AN EQUALLY LARGE AND INTENSIFYING MID-LATITUDE

LOW. OVER THE LAST 24 HOURS THE STEERING WINDS WERE LIGHT OUT OF

THE EAST-SOUTHEAST AROUND THE RIDGE AND IN THE GENERAL DIRECTION OF

THE LOW...RESULTING IN THE WEST-NORTHWEST DRIFT OF NEKI. THE

SURFACE LOW AND FRONT EXTENDING SOUTHWEST OF THE LOW...ALONG WITH A

LONGWAVE UPPER LEVEL TROUGH...HAVE MOVED TO THE EAST HOWEVER...

PLACING NEKI IN INCREASINGLY STRONGER SOUTHERLY STEERING WINDS.

WITH THE DEEP LAYER MEAN FLOW NOW INCREASING OUT OF THE SOUTH AND

SOUTHWEST...THE VERTICAL SHEAR AS CALCULATED BY UW-CIMSS HAS

DROPPED OFF...AND IS NO LONGER A MAJOR PLAYER. THE SHEAR IS NOT

EXPECTED TO INCREASE...SO NEKI IS KEPT AT 35 KT THROUGH THE NEXT 36

HOURS. THE LARGEST 35 KT WIND RADII IS IN THE NORTHEAST QUADRANT

WHERE THERE IS A TIGHT PRESSURE GRADIENT BETWEEN NEKI AND THE

RIDGE. THE INTENSITY FORECAST IS IN THE MIDDLE OF THE ENVELOP...

CLOSEST TO GFNI AND AVNI.

WITH NEKI UNDER THE INCREASING INFLUENCE OF THE STRENGTHENING LOW TO

THE NORTHWEST...IT/S FORWARD MOTION SHOULD DRAMATICALLY INCREASE

OVER THE NEXT 36 HOURS. THE TRACK FORECAST WHICH REFLECTS THIS IS IN

THE MIDDLE OF THE OBJECTIVE AIDES...AND IS CLOSEST TO THE VARIOUS

CONSENSUS FORECASTS. NEKI IS FORECAST TO TRANSITION INTO AN

EXTRATROPICAL LOW AND BE ABSORBED INTO THE MID-LATITUDE LOW IN 24 TO

36 HOURS.

FORECAST POSITIONS AND MAX WINDS

INITIAL 26/0900Z 25.9N 165.5W 35 KT

12HR VT 26/1800Z 27.7N 165.3W 35 KT

24HR VT 27/0600Z 32.0N 164.0W 35 KT...EXTRATROPICAL

36HR VT 27/1800Z 38.5N 160.9W 35 KT...EXTRATROPICAL

48HR VT 28/0600Z...EXTRATROPICAL

$$

FORECASTER CRAIG

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final advisory issued

Final Advisory

TROPICAL DEPRESSION NEKI DISCUSSION NUMBER 34

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI CP032009

500 PM HST MON OCT 26 2009

ALL THAT IS LEFT OF NEKI IS AN ILL-DEFINED...ELONGATED SWIRL OF LOW

CLOUDS. ALTHOUGH THERE WERE NO RECENT SCATTEROMETER PASSES

AVAILABLE...NEKI APPEARS TO BE JUST A SURFACE TROUGH IN SATELLITE

IMAGERY. DECREASING SEA SURFACE TEMPERATURES ALONG THE TRACK AND

INCREASING VERTICAL SHEAR SHOULD PREVENT REDEVELOPMENT AS A TROPICAL

CYCLONE. THUS...THIS IS THE FINAL ADVISORY ON NEKI.

FORECAST POSITIONS AND MAX WINDS

INITIAL 27/0300Z 30.3N 164.9W 30 KT

12HR VT 27/1200Z 34.6N 163.6W 30 KT...DISSIPATING

24HR VT 28/0000Z...DISSIPATED

$$

FORECASTER R BALLARD

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