• Member Statistics

    15,856
    Total Members
    7,904
    Most Online
    freestyle
    Newest Member
    freestyle
    Joined
Sign in to follow this  
Windspeed

Hurricane Ana

Recommended Posts

CP022014W.gif

WTPA45 PHFO 181508TCDCP5HURRICANE ANA DISCUSSION NUMBER  20NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   CP022014500 AM HST SAT OCT 18 2014 LATEST SATELLITE IMAGERY SHOWS SEVERELY RESTRICTED OUTFLOW IN ANA/S WESTERN SEMICIRCLE...WITH 20 TO 25 KT OF SOUTHWESTERLY SHEAR NOTED IN RECENT UW-CIMSS ANALYSES. HOWEVER...DATA FROM A U.S. AIR FORCE RECONNAISSANCE AIRCRAFT INDICATE THAT ANA HAS NOT WEAKENEDSIGNIFICANTLY SINCE THE PREVIOUS ADVISORY...WITH MAXIMUM SFMR WINDSNEAR 67 KT...AND MAXIMUM FLIGHT LEVEL WINDS OF 75 KT. A BLEND OF THE AVAILABLE DATA SUPPORTS LOWERING THE INITIAL INTENSITY TO 70 KT FOR THIS ADVISORY. INITIAL MOTION FOR THIS ADVISORY IS SET AT 315/11 KT...WITH ANA LOCATED ON THE SOUTHWEST PERIPHERY OF A LOW TO MID-LEVELANTICYCLONE. A WEAK RIDGE EXTENDS WESTWARD FROM THIS ANTICYCLONE...AND TO THE NORTH OF ANA...AND WILL HELP MAINTAIN THE CURRENT MOTIONTHROUGH MOST OF TODAY. A NEW RIDGE BUILDING EASTWARD FROM THE DATELINE TONIGHT AND SUNDAY WILL RESULT IN A SLIGHT DECREASE IN FORWARDSPEED...AND A TURN TOWARD THE WEST. ALTHOUGH ANA HAS BEEN TRACKINGSLIGHTLY TO THE RIGHT OF THE SHORT TERM FORECAST TRACK...THE UPDATEDTRACK FORECAST IS LEFT OF THE PREVIOUS AT 24 AND 36 HOURS. THIS ISIN LINE WITH THE GUIDANCE SUITE...BUT THE OFFICIAL FORECASTCONTINUES TO RIDE THE RIGHT HAND SIDE OF THE GUIDANCE IN THE SHORTTERM. WHILE THE GUIDANCE...AND THE FORECAST...REMAINS STEADFAST IN ATURN TOWARD THE WEST BY TONIGHT...IF THE TURN OCCURS LATER OR IS NOTAS SHARP AS ANTICIPATED...WINDS ON THE PERIPHERY OF ANA COULD IMPACTOAHU OR KAUAI COUNTY...THUS A TROPICAL STORM WATCH REMAINS INEFFECT. CONFIDENCE HAS INCREASED THAT MAUI COUNTY WILL NOT ENCOUNTERANA/S WIND FIELD...AND THE TROPICAL STORM WATCH HAS BEEN CANCELLED.THE GENERAL MOTION TOWARD THE WEST WILL PERSIST ON MONDAY...BUT ASTHE NEW RIDGE SLIDES EAST OF THE CYCLONE ON TUESDAY AND WEDNESDAY...ANA IS FORECAST TO MOVE ON AN INCREASINGLY NORTHWARD TRACK. BY DAYS4 AND 5...ANA IS FORECAST TO BE NEAR THE PAPAHANAUMOKUAKEA MARINENATIONAL MONUMENT...WITH TRACK GUIDANCE SHOWING INCREASING SPREAD ATTHAT TIME.  ANA IS FORECAST TO MAINTAIN ITS CURRENT INTENSITY OVER THE NEXT 12HOURS...WITH MODEST WEAKENING THEN EXPECTED THROUGH DAY 3.PERSISTENT WESTERLY SHEAR IS EXPECTED TO PREVENT ANAFROM INTENSIFYING OVER THE ANOMALOUSLY WARM WATER LOCATED TO THEWEST AND NORTHWEST OF THE MAIN HAWAIIAN ISLANDS...UNTIL THE SHEARBEGINS TO RELAX ON DAYS 4 AND 5. INTENSITY GUIDANCE IS OFFERING AWIDE RANGE OF SOLUTIONS AT THIS TIME...WITH THE LATEST FORECASTCLOSELY FOLLOWING THE TRENDS PRESENTED BY SHIPS AND LGEMGUIDANCE...WHICH INDICATE SOME RE-STRENGTHENING. THE IVCN CONSENSUSCONTINUES TO BE MUCH HIGHER THAN THE OFFICIAL FORECAST IN THE LONGERRANGES...AS HWRF AND GFDL STRENGTHEN ANA TO A STRONG HURRICANE.   FORECAST POSITIONS AND MAX WINDS INIT  18/1500Z 18.5N 158.1W   70 KT  80 MPH 12H  19/0000Z 19.4N 159.3W   70 KT  80 MPH 24H  19/1200Z 19.9N 160.7W   65 KT  75 MPH 36H  20/0000Z 20.3N 162.2W   60 KT  70 MPH 48H  20/1200Z 20.6N 163.8W   60 KT  70 MPH 72H  21/1200Z 22.0N 166.3W   60 KT  70 MPH 96H  22/1200Z 24.0N 168.0W   65 KT  75 MPH120H  23/1200Z 26.5N 168.5W   70 KT  80 MPH $$FORECASTER BIRCHARD

Share this post


Link to post
Share on other sites

This actually has a chance to make landfall on or clip Oahu... so it should definitely be watched.  I don't think there is as high of a chance of RI as there was with Gonzalo fortunately.

 

(Also I wish they had another name since Ana is also an Atlantic name.)

Share this post


Link to post
Share on other sites

ECMWF doesn't look too impressive. It may deepen more than expected early, but shear will have a couple days to eat away at it before landfall.

Share this post


Link to post
Share on other sites

The Euro does horrible with deep tropical systems. I would not be so convinced shear is gonna kill it. As for track, I'm thinking it brushes the Big Island and passes near Oahu.

 

There will likely be some weakening, yes, but there could be some intensification as well as indicated by both the GFDL and HWRF.

Share this post


Link to post
Share on other sites

The core of Ana taking advantage of some really impressive atmospheric conditions. The upper ridge is placed perfectly with minimal shear on the system and divergent flow aloft. The center also appears to be moving just south of due west right now, which could be very important in that, one, ultimately will have a bearing on exactly which island to be most impacted, and two, the eyewall is traversing 28ºC water.

 

post-845-0-14089500-1413349172_thumb.gif

 

Update: Think I may have jumped the gun on RI beginning earlier. IR looked terrific with a very circular convective ring as you can see above. However, the satellite presentation may be misleading. Can't be certain that the mid-level vortex is aligned with the overall LLC at the moment. The MCS might just be rotating off intense cells on the SW side of the LLC based on microwave imagery and may not be a true center. Then again, small vortexes don't always show up well on microwave and can be just as misleading as IR. Recon sure would be nice right now.

Share this post


Link to post
Share on other sites

Same issue as earlier. The mid-level vortex of the MCS remains mighty impressive, however, it's still not aligned with the LLC as it is rotating up off intense cells that remain displaced on the SW side of the overall surface circulation. Mid-level northwesterly shear must still either be affecting the system or the LLC simply fails to reorganizing under the MLC. May be a slow strengthening trend until shear backs off at the mid-levels. The upper level outflow looks to be there when this occurs and there is plenty of divergence aloft as noted in the persistent cold spinning MCS feature.

 

post-845-0-35801400-1413381034_thumb.jpg

Share this post


Link to post
Share on other sites

Euro, shows Oahu almost getting in the eye followed by a Kuaii landfall.  It's about 992mb 55kts on wundermap for both landfalls.

Share this post


Link to post
Share on other sites

The CPHC is backing off on intensity along with the models. They're now calling for Ana to pass near Oahu and Kauai as a TS. The satellite presentation definitely doesn't look as impressive as earlier. It also looks like it will stay a bit further south off the Big Island. It seems more typical for storms that go through this region...

Share this post


Link to post
Share on other sites

Tough forecast for them. Not too much has to evolve with those upper features either way to switch from a mere weakening tropical storm to a strengthening hurricane. The shear axis is literally just a few hundred miles over the northern half of the LLC as opposed the the southern half. Plus you've still got to consider how that pattern evolves out through Sunday as opposed to the track shifting further west. I must say its no wonder they're not nearly as confident of Ana impacting the islands as a hurricane with its status quo. But in this case, there still appears plenty of uncertainty and in no way should it be written off yet as a typical tropical cyclone encounter with the island chain.

Share this post


Link to post
Share on other sites

Models keep shifting more and more west as Ana continues moving that direction. The vast majority of models are now calling for it to remain a TS as well. 

 

Yeah, for now it looks like there will be strong mid-level shear impacting the system as it parallels the chain on Sunday. Probably not going to maintain hurricane intensity at that point (if it even attains hurricane intensity at all), though the models should have a better handle on the intereaction/timing of both upper level features after that Gulf Steam IV data gets ingested for the models tonight. This could easily miss the bigger islands entirely but I'd like to be more confident about that. Let's see what those model runs do tonight.

Share this post


Link to post
Share on other sites

Ana may remain an identifiable tropical system all the way to 40N, something rare in the Central Pacific.

Remnats are foretasted to slam into the Pacific NW day 7-8.

Share this post


Link to post
Share on other sites

Remnats are foretasted to slam into the Pacific NW day 7-8.

Yes, its playing heck with the models.  The spaghetti chart has a 500+ mile range on where it hits the west coast.

Share this post


Link to post
Share on other sites

Storm rainfall totals approached 20" over the open ocean south of Honolulu. These are the storm total images from last night, from two of the four Hawaii radars.

 

A few Oahu storm totals (full text here http://www.prh.noaa.gov/data/HFO/PNSHFO.1410200650)

OAHU/MNLH1/ MANOA LYON ARBO                        11.05/PMHH1/ POAMOHO RG 1 - USGS                     7.47/MOGH1/ MOANALUA - USGS - USGS                  6.89/PNSH1/ PUNALUU STREAM - USGS                   5.77/HNL  / HONOLULU AIRPORT                        4.72

post-1182-0-16966900-1413951075_thumb.jp

 

post-1182-0-27637600-1413951102_thumb.jp

 

 

 

 

 

 

 

 

Share this post


Link to post
Share on other sites

Made it all the way to 42.2N before ET transition.

 

It's actually closer to Oregon/Washington than Hawaii.  I can't ever remember that happening, except for that weird 1975 freak storm.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this  

  • Recently Browsing   0 members

    No registered users viewing this page.