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Major Hurricane Hernan


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Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds. HATE:stagnant weather patterns
  • Location: Taunton, Somerset

    Tropical Depression 09E has formed in the East Pacific, and has an initial intensity of 30kts. Convection is very deep over the well defined centre, and the depression is expected to strengthen into Tropical Storm Hernan soon. The new cyclone has about three days over warm waters to strengthen, and the NHC currently have 09E peaking at 60kts, so this one may become a hurricane before it hits those cooler waters on the west-northwestward track. With the favourable conditions including low shear, this definitely isn't out of the question.

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    Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds. HATE:stagnant weather patterns
  • Location: Taunton, Somerset

    TD09E has become better organised overnight and has been upgraded to Tropical Storm Hernan. Hernan is being affected by northeasterly shear, which is leaving the centre slightly displaced east of the deep convection. However, shear is expected to ease and Hernan is now forecast by the NHC to briefly become a hurricane before reaching those cooler waters beyond 72hrs. The track forecast has not changed.

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    Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds. HATE:stagnant weather patterns
  • Location: Taunton, Somerset

    Hernan has strengthened this afternoon in the face of northeasterly shear. The LLC remains partially exposed but in the southwestern quadrant of the storm is some very deep and persistant convection. Intensity has been increased to 50kts, and Hernan could become a hurricane later tomorrow before moving over cooler waters.

    Image of Hernan on right (also shows TS Kika on left):

    xxirg9bbm.jpg

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    Posted
  • Location: Liphook
  • Location: Liphook

    Hernan looks pretty good right now, T-numbers now upto 4.0 which does suggest an upgrade should be soon, though given the slightly lop-sided nature of the deepest convection they may hold back for another 6hrs but this has got some very impressive convection right now with some really cold cloud tops.

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    Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds. HATE:stagnant weather patterns
  • Location: Taunton, Somerset
    Hernan looks pretty good right now, T-numbers now upto 4.0 which does suggest an upgrade should be soon, though given the slightly lop-sided nature of the deepest convection they may hold back for another 6hrs but this has got some very impressive convection right now with some really cold cloud tops.

    Indeed, the upgrade has now been made and Hernan is a 65kt hurricane. Favourable conditions will persist over the next 36hrs and therefore further strengthening is predicted. Beyond this time period, cooler waters await Hernan which will induce slow weakening.

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    Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds. HATE:stagnant weather patterns
  • Location: Taunton, Somerset

    Hernan has strengthened further, and is now at 75kts. The eye continues to get better defined. Hernan is moving generally westwards and should remain over warm waters for another 36hrs, so further strengthening is predicted. The NHC expect Hernan to peak at 85kts, though it is plausible for Hernan to get a little stronger than that as the environment remains favourable for the next day or so.

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    Posted
  • Location: Saddleworth, Oldham , 175m asl
  • Weather Preferences: warm and sunny, thunderstorms, frost, fog, snow, windstorms
  • Location: Saddleworth, Oldham , 175m asl

    Big increase in strength since I last checked, now a 105 knot Cat 3 Hurricane!

    THE EYE OF HERNAN HAS BECOME DRAMATICALLY MORE DISTINCT IN GOES

    INFRARED IMAGERY DURING THE PAST SEVERAL HOURS...AND IT IS NOW

    SURROUNDED BY A SOLID RING OF CLOUD TOPS COLDER THAN -70C. AMSR-E

    MICROWAVE IMAGERY AT 0937 UTC DEPICTED A SINGLE COMPLETE EYEWALL

    AND AN EYE DIAMETER OF 20-25 N MI. THERE SEEMS LITTLE DOUBT THAT

    HERNAN HAS BECOME A MAJOR HURRICANE... HAVING UNDERGONE RAPID

    INTENSIFICATION SINCE YESTERDAY. THIS PROVIDES YET ANOTHER EXAMPLE

    OF THE INABILITY OF MODEL GUIDANCE...AND THEREFORE THE HUMAN

    FORECASTER...TO CAPTURE AND CONVEY THE TIMING AND MAGNITUDE OF THESE

    EPISODES WITH A DETERMINISTIC INTENSITY FORECAST. THE EXACT

    INITIAL INTENSITY IS A LITTLE UNCERTAIN. SUBJECTIVE DVORAK

    ESTIMATES AT 12Z FROM TAFB AND SAB WERE BOTH 102 KT...WHILE

    OBJECTIVE ESTIMATES ARE ABOUT 115 KT. THE ADVISORY INTENSITY

    COMPROMISES AT 105 KT...BUT WITHOUT ACTUAL WIND DATA TO KNOW ANY

    BETTER...IT IS POSSIBLE HERNAN IS A LITTLE STRONGER THAN THIS

    ESTIMATE. UNDERLYING SEA-SURFACE TEMPERATURES ARE ABOUT 27 CELSIUS

    NOW...AND ALONG THE FORECAST TRACK THE HURRICANE WILL CROSS THE 26

    CELSIUS ISOTHERM IN ROUGHLY 24 HOURS...SO A GRADUAL WEAKENING TREND

    IS FORECAST TO BEGIN AROUND THAT TIME. A FASTER DECLINE IS

    FORECAST IN A COUPLE OF DAYS ONCE THE CYCLONE REACHES SUBSTANTIALLY

    COOLER WATERS. THE OFFICIAL FORECAST IS ABOVE THE OBJECTIVE

    GUIDANCE FOR THE NEXT DAY OR TWO...THEN SHOWS A FASTER WEAKENING

    THAN THE MODELS DUE TO THE SMALL SIZE OF THE CYCLONE.

    HERNAN HAS TURNED A LITTLE MORE TO THE RIGHT...AND ONE MUST GIVE

    SOME OF THE MODELS CREDIT FOR CORRECTLY FORECASTING THIS BEND

    YESTERDAY. THE INITIAL MOTION ESTIMATE IS 295/8...BUT A GRADUAL

    TURN BACK TO THE LEFT IS FORECAST BY ALL OF THE DYNAMICAL MODELS AS

    THE SUBTROPICAL RIDGE BUILDS WESTWARD OVER THE EASTERN PACIFIC

    DURING THE NEXT COUPLE OF DAYS. BEYOND THAT TIME...A WEAKENING

    HERNAN IS EXPECTED TO BECOME A MORE SHALLOW SYSTEM AND TURN

    WESTWARD AND EVENTUALLY WEST-SOUTHWESTWARD IN THE LOW- TO MID-LEVEL

    FLOW. THE NEW OFFICIAL TRACK FORECAST IS ALMOST IDENTICAL TO THE

    PREVIOUS ONE AND IS CLOSE TO THE MODEL CONSENSUS.

    FORECASTER KNABB

    vis.jpg

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    Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds. HATE:stagnant weather patterns
  • Location: Taunton, Somerset

    Yes, Hernan has become the first major hurricane of the East Pacific season. I didn't foresee it getting quite this strong but I always though the NHC was punting a little low with the intensity, as shear was low and Hernan still has a while over very warm waters. Still has potential to get a little stronger, it's a case of wait and see to see just how high Hernan goes.

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    Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds. HATE:stagnant weather patterns
  • Location: Taunton, Somerset

    Hernan has weakened to 85kts, and the eye has become more rugged overnight. Hernan is moving over cooler waters below 27C which is being held accountable for the weakening. Even cooler waters lie in the forecast track so Hernan will continue to weaken, the NHC say Hernan may lose hurricane status in the next 24hrs. Interestingly, around 120hrs time, waters are expected to warm up again, but it's too early to tell whether Hernan will make a comeback from it's expected tropical depression status by then.

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    Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds. HATE:stagnant weather patterns
  • Location: Taunton, Somerset

    Hernan has continued to weaken over cool waters, and is now a 60kt tropical storm. Further weakening will occur as waters remain too cool for development. However, beyond 96hrs, sea temps are expected to increase again on the westwards track which may prolong the life of the cyclone, if it survives that long.

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    Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds. HATE:stagnant weather patterns
  • Location: Taunton, Somerset

    Hernan now consists of a small, tight circulation with patchy, shallow convection flaring near the centre. Intensity is decreased to 55kts simply because there are still some pretty strong winds in the tight core. However, given Hernan's convectional state, the cyclone may not be around for much longer, and probably won't be by the time it finds warmer waters to the west. NHC expect degeneration into a remnant low by 72hrs.

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    Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds. HATE:stagnant weather patterns
  • Location: Taunton, Somerset

    Hernan continues to spin down over cool waters. Intensity is now at 35kts and very little convection remains near the still well defined centre.

    post-1820-1218579742_thumb.jpg

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