EPAC: Tropical Storm Hernan

[UKane]

000
WTPZ44 KNHC 081459
TCDEP4
HURRICANE HERNAN DISCUSSION NUMBER 8
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP092008
800 AM PDT FRI AUG 08 2008

AFTER A NOTICEABLE BURST OF DEEP CONVECTION THIS MORNING...SATELLITE
IMAGERY INDICATES A CDO FEATURE NOW PRESENT WITH A HINT OF A RAGGED
EYE WITHIN THE PAST FEW HOURS. WITH DVORAK SATELLITE ESTIMATES NOW
AT T4.0 FROM BOTH TAFB AND SAB AND GIVEN RECENT TRENDS...HERNAN IS
UPGRADED TO A HURRICANE. IN THE SHORT-TERM...SHIPS MODEL OUTPUT
SUGGESTS LIGHT EASTERLY SHEAR AMONGST OTHER FAVORABLE FACTORS
AND...ALONG THE FORECAST TRACK...HERNAN SHOULD REMAIN OVER 26
CELSIUS SSTS FOR AT LEAST THE NEXT 48 HOURS. ON THIS BASIS...THE
EXPECTATION IS THAT HERNAN SHOULD CONTINUE STRENGTHENING FOR THE
NEXT 24 HOURS BUT SHOULD BEGIN WEAKENING AFTER IT REACHES COOLER
WATERS AND A MORE STABLE ATMOSPHERE...ESPECIALLY BEYOND 48 HOURS.
GIVEN THE INCREASING ORGANIZATION APPARENT IN RECENT SATELLITE
IMAGERY...AND NO APPARENT HINDRANCES TO STRENGTHENING...THE NEW
OFFICIAL INTENSITY FORECAST IS HIGHER THAN THE PREVIOUS ADVISORY
AND ABOVE NEARLY ALL OF THE OBJECTIVE GUIDANCE.

THE INITIAL MOTION IS SET AT 275/11...WHICH IS VERY SIMILAR TO THE
HEADING DURING THE LAST 24 HOURS. THE TRACK IS ADJUSTED
SOUTHWARD...HOWEVER...AFTER REVIEWING A HOST OF MICROWAVE IMAGERY
THIS MORNING...WHICH ALSO SUGGESTS THAT THE LOW-LEVEL AND MID-LEVEL
CENTERS ARE NOW VERTICALLY ALIGNED. MID-LEVEL RIDGING EXTENDING
FROM NORTHERN MEXICO SOUTHWESTWARD TO NORTH OF THE TROPICAL CYCLONE
SHOULD CONTINUE THE HURRICANE ON A GENERAL WESTWARD TO
WEST-NORTHWESTWARD TRACK THE NEXT FEW DAYS...WITH THE OFFICIAL
TRACK ON THE LEFT SIDE OF THE GUIDANCE ENVELOPE. THEREAFTER...A
GRADUAL WEAKENING SHOULD CAUSE THE STORM TO BE STEERED MORE WITH
THE LOW- TO MID-LEVEL FLOW...ON A MORE WESTWARD AND POSSIBLY
WEST-SOUTHWESTWARD COURSE BY THE END OF THE PERIOD.


FORECAST POSITIONS AND MAX WINDS

INITIAL 08/1500Z 14.7N 119.9W 65 KT
12HR VT 09/0000Z 14.8N 121.6W 75 KT
24HR VT 09/1200Z 15.1N 123.4W 80 KT
36HR VT 10/0000Z 15.5N 125.0W 75 KT
48HR VT 10/1200Z 16.1N 126.6W 65 KT
72HR VT 11/1200Z 17.0N 130.0W 45 KT
96HR VT 12/1200Z 17.0N 132.5W 35 KT
120HR VT 13/1200Z 16.5N 135.0W 25 KT

$$
FORECASTER KNABB/KIMBERLAIN


I think that the 96HR and 120HR is wrong....

Hes moving south towards warmer water at that point.... he will intensify.

[Chacor]

Why is that 'interesting'? All the EPac storms have died around 130W, so not much chance one would cross over in those poor SSTs...

[Chacor]

I think that the 96HR and 120HR is wrong....

Hes moving south towards warmer water at that point.... he will intensify.

Uh... warm waters aren't the be-all-and-end-all. Pretty bold to outright say that the NHC is wrong and that it "will" intensify at that point.

[KWT]

SST's further west Ukane still probably too low and will help to induce weakening that far to the north, esp if the upper conditions do beocme less favorable.

[HURAKAN]

Looking better and better.

[HURAKAN]

Eye becoming more visible.

[HURAKAN]

Impressive. Now that both MLC and LLC are aligned, it's GO TIME!

[HURAKAN]

Eye becoming more defined in the visible images.

[Category 5]

96HR VT 12/1200Z 17.0N 132.5W 35 KT
120HR VT 13/1200Z 16.5N 135.0W 25 KT

I think that the 96HR and 120HR is wrong....

Hes moving south towards warmer water at that point.... he will intensify.

Oh yeah, thats moving south alright, it's just gaining longitiude while doing it .

[HURAKAN]

1 ... 2 ... 3 ... BOOM!

[Cyclenall]

The ACE for the eastern Pacific has now surpassed the Atlantic by 0.1 ACE!! Yes, this is a below normal season alright .

My prediction is in danger if it gets any stronger then 65 knots. That was a huge forecast change from 5:00 am.

[Category 5]

1 ... 2 ... 3 ... BOOM!

Not the best looking Hurricane we've seen, but certainly a very respectable looking one.

http://www.ssd.noaa.gov/goes/flt/t6/sloop-rgb.html

[HURAKAN]

Looking much better now:

[HURAKAN]

[HURAKAN]

[HURAKAN]

08/1800 UTC 14.8N 120.3W T4.0/4.0 HERNAN -- East Pacific Ocean

4.0 makes no sence, Hernán is between 4.5 and 5.0.

[HURAKAN]

EP, 09, 2008080818, , BEST, 0, 147N, 1204W, 70, 983, HU,

[cycloneye]

WTPZ44 KNHC 082048
TCDEP4
HURRICANE HERNAN DISCUSSION NUMBER 9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP092008
200 PM PDT FRI AUG 08 2008

THE RAGGED EYE FEATURE FROM THIS MORNING HAS PERSISTED INTO THE
AFTERNOON...AND LATEST SATELLITE IMAGERY INDICATES THAT THE EYE IS
BECOMING BETTER DEFINED. DVORAK SATELLITE CLASSIFICATIONS REFLECT
THIS INCREASING ORGANIZATION...WITH TAFB AND SAB COMING IN WITH
T4.5 AND T4.0...RESPECTIVELY. ON THIS BASIS...THE INITIAL INTENSITY
IS SET AT 75 KT. LIGHT EASTERLY SHEAR AND OTHER FAVORABLE FACTORS
PREDICTED ALONG THE FORECAST TRACK SHOULD GIVE HERNAN THE
OPPORTUNITY TO INTENSIFY FURTHER DURING THE NEXT 24 TO 36 HOURS.
HOWEVER...BETWEEN 36 AND 48 HOURS...HERNAN SHOULD REACH SUB-26C
SSTS AND BEGIN A GRADUAL WEAKENING. THE OFFICIAL INTENSITY FORECAST
LIES SLIGHTLY ABOVE ALL OBJECTIVE AIDS AS WELL AS THE PREVIOUS
ADVISORY.

THE HEADING IS 275/10...A MOTION WHICH HAS REMAINED NEARLY UNCHANGED
DURING THE PAST DAY OR SO. NEARLY ALL OF THE TRACK GUIDANCE TURNS
HERNAN MORE TOWARD THE NORTHWEST VERY SOON...LIKELY IN RESPONSE TO
A PRONOUNCED MID- TO UPPER-LEVEL TROUGH LYING WELL NORTHWEST OF THE
HURRICANE. HOWEVER...WATER VAPOR CLOUD-TRACKED WINDS SHOW A SMALL
MID-LEVEL RIDGE AXIS LYING DIRECTLY NORTH OF HERNAN...WHICH HAS
BEEN GUIDING IT ON A MORE WESTERLY COURSE. THIS FEATURE SEEMS TO BE
UNDER-REPRESENTED IN THE GLOBAL MODEL FIELDS AND PERHAPS THIS IS
WHY THE MODEL GUIDANCE HAS BEEN EXHIBITING A NORTHWARD BIAS WITH
HERNAN. CONSEQUENTLY...THE NEW OFFICIAL FORECAST REMAINS ON THE
SOUTHERN EDGE OF THE GUIDANCE ENVELOPE. IN 24 TO 48 HOURS...MODEL
GUIDANCE IS IN GOOD AGREEMENT ON THE MID-LEVEL RIDGE BUILDING
WESTWARD WITH THE HURRICANE AS THE MID- TO UPPER-LEVEL TROUGH TO
THE NORTH LIFTS OUT. THIS SHOULD ALLOW THE TRACK TO BEND MORE
TOWARD THE WEST AND PERHAPS EVEN TO THE WEST-SOUTHWEST LATE IN THE
PERIOD...AS A WEAKER HERNAN BECOMES STEERED BY THE LOW- TO
MID-LEVEL FLOW.

FORECAST POSITIONS AND MAX WINDS

INITIAL 08/2100Z 14.8N 120.9W 75 KT
12HR VT 09/0600Z 15.0N 122.3W 85 KT
24HR VT 09/1800Z 15.4N 124.0W 85 KT
36HR VT 10/0600Z 16.1N 125.7W 75 KT
48HR VT 10/1800Z 16.7N 127.4W 65 KT
72HR VT 11/1800Z 17.0N 130.5W 45 KT
96HR VT 12/1800Z 17.0N 133.0W 35 KT
120HR VT 13/1800Z 16.5N 135.0W 25 KT

$$
FORECASTER KIMBERLAIN/BROWN

[HURAKAN]

Looking solid.

[Cyclenall]

000
WTPZ34 KNHC 082045
TCPEP4
BULLETIN
HURRICANE HERNAN ADVISORY NUMBER 9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP092008
200 PM PDT FRI AUG 08 2008

...HERNAN SLOWLY STRENGTHENING...

I don't think 10 knots in 6 hours is slow strengthening, and certainly not 20 knots in 12 hours!