WPAC: PEIPAH - Tropical Depression

[euro6208]

Yes but Guam is not part of Asia. I know that Guam is part of the US territory. 26.8% of those there are Filipinos. Standards of US and Guam websites ONLY. Just dont argue with us as the rest of the world except India and US and its territories follow the 10 min standard. FRANCE, ITALY, UK, JAPAN, KOREA AND OTHER MORE.

Guam is in the western pacific with Asia...

i didn't start this so can we now lay this to rest?

[euro6208]

06Z GFS has peipah remaining just east of the p.i for 5 more days before landfall although weak.

[wxman57]

there you go with ASCAT...

since i'm not familiar with it and many others in this forum, what exactly is a koba scale? is it equivalent to the dvorak scale that we use? what other data do they use to determine the strength of a TC?

I would love to learn more about this official agency JMA.

Check this out:
https://www.wmo.int/pages/prog/www/tcp/documents/JMAoperationalTCanalysis.pdf

It appears that the JMA assumes a Dvorak of 2.0 = tropical storm, which is a lower standard than other agencies.

[euro6208]

there you go with ASCAT...

since i'm not familiar with it and many others in this forum, what exactly is a koba scale? is it equivalent to the dvorak scale that we use? what other data do they use to determine the strength of a TC?

I would love to learn more about this official agency JMA.

Check this out:
https://www.wmo.int/pages/prog/www/tcp/documents/JMAoperationalTCanalysis.pdf

It appears that the JMA assumes a Dvorak of 2.0 = tropical storm, which is a lower standard than other agencies.

thanks for that...

very confusing...

does any of the JMA guys even know anything about this or do they assume since they are official, they are always correct...

i'm sticking to my 1 min...

https://www.wmo.int/pages/prog/www/tcp/documents/JMAoperationalTCanalysis.pdf

[dexterlabio]

We all know there's a respective RSMC for each basin but it doesn't mean we can't question their forecasts...especially if people have evidence to back them up..



It's funny though that people themselves have their own bias...if they favor what the JTWC has forecast then they ignore the JMA warnings...same way when people favor the JMA forecast and call JTWC 'unofficial'...

[wxman57]

New ASCAT just in. Max winds 25 kts and an elongated LLC that's well-removed from the MLC about 120 miles to the NW (near 10.2N/128E and off the chart below). Clearly, the trend is toward weakening not strengthening.

[xtyphooncyclonex]

I may now be on JTWC's side. I would actually personally go below 25 kts. Shear may relax late tomorrow. JMA is stuck at 35 kts.

[euro6208]

I may now be on JTWC's side. I would actually personally go below 25 kts. Shear may relax late tomorrow. JMA is stuck at 35 kts.

well shouldn't you be? your countries weather agency PAGASA is also calling this a TD...

[euro6208]

New ASCAT just in. Max winds 25 kts and an elongated LLC that's well-removed from the MLC about 120 miles to the NW (near 10.2N/128E and off the chart below). Clearly, the trend is toward weakening not strengthening.

close to JT...

WDPN31 PGTW 081500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 05W (PEIPAH)
WARNING NR 23//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL DEPRESSION (TD) 05W (PEIPAH), LOCATED APPROXIMATELY 631
NM EAST-SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED NORTH-
NORTHWESTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED
INFRARED IMAGERY (EIR) DEPICTS SLOW CONSOLIDATION OF DEEP CONVECTION
CLUSTERS WITH FORMATIVE BANDING AROUND A LOW LEVEL CIRCULATION
CENTER (LLCC). A MOSAIC OF RECENT MICROWAVE IMAGERY SUGGESTS THERE
MAY BE SEVERAL WEAK VORTICES ROTATING AROUND THE LLCC, WHICH MAY BE
HAMPERING THE LOW LEVEL DEVELOPMENT. THE INITIAL POSITION IS BASED
ON A CENTROID OF POSSIBLE CENTERS BASED ON THE AFOREMENTIONED EIR
AND MICROWAVE IMAGERY WITH POOR CONFIDENCE. UPPER LEVEL ANALYSIS
REVEALS MODERATE (15-20 KNOTS) EASTERLY VERTICAL WIND SHEAR (VWS),
WITH SOME SLIGHT UPPER LEVEL TROUGHING IMPINGING ON THE SOUTHWEST
CORNER OF THE SYSTEM, HOWEVER THESE NEGATIVE EFFECTS ARE OFFSET BY
STRONG DIFFLUENCE AND GOOD POLEWARD OUTFLOW. THE INITIAL INTENSITY
IS ASSESSED AT 30 KNOTS BASED ON DVORAK CURENT INTENSITY ESTIMATES
FROM ALL AGENCIES. TD 05W HAS TRACKED ERRATICALLY OVER THE PAST 12
HOURS, PARTIALLY AS A RESULT OF THE POOR CERTAINTY OF THE BEST
TRACK. TD 05W IS IN A WEAK STEERING ENVIRONMENT, AS THE WESTERN
EXTENT OF THE SUB-TROPICAL RIDGE (STR) IS BEING ERODED.
3. FORECAST REASONING.
A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. TD 05W IS FORECAST TO REMAIN IN THE WEAK STEERING ENVIRONMENT
THROUGH TAU 48 AND TRACK SLOWLY NORTHWESTWARD TOWARD THE WEAKNESS IN
THE SUBTROPICAL RIDGE (STR). DYNAMIC GUIDANCE VARIES GREATLY BOTH IN
DIRECTION AND SPEED OF MOTION. THIS UNCERTAINTY IS ALSO REFLECTED IN
NUMEROUS ENSEMBLE MODEL PRODUCTS. THE MULTI-MODEL CONSENSUS SHIFTED
SOUTHWARD DURING THIS CYCLE. THE JTWC FORECAST TRACK IS SHIFTED
SLIGHTLY SOUTHWARD TO ACCOUNT FOR THIS, BUT REMAINS NORTH OF THE
CONSENSUS TAKING INTO ACCOUNT SOME UNLIKELY MODEL OUTLIERS. TD 05W
SHOULD GRADUALLY INCREASE TO AN INTENSITY OF 40 KNOTS BY TAU 48 AS
THE FOREWARD MOTION BEGINS TO INCREASE AND THE SYSTEM TRACKS INTO
LOWER VWS, BUT THIS INTENSIFICATION MAY NOT OCCUR IF THE LOW LEVEL
STRUCTURE DOES NOT BECOME MORE ORGANIZED.
C. IN THE EXTENDED TAUS, TD 05W IS EXPECTED TO TURN WEST-
NORTHWESTWARD AND ACCELERATE AS THE STR RE-BUILDS NORTH OF THE
SYSTEM. THE JTWC FORECAST TRACK SPEEDS HAVE BEEN ADJUSTED DOWNWARD
RELATIVE TO PRIOR FORECASTS TO TAKE INTO ACCOUNT THE SLOWER MOTION
OBSERVED IN THE NUMERICAL GUIDANCE. TD 05W SHOULD WEAKEN AS IT
TRACKS OVER THE PHILIPPINES, WITH MODELS INCREASINGLY FAVORING
DISSIPATION OVER THE CENTRAL PHILIPPINES BY TAU 120. DUE TO THE
UNCERTAINTY IN THE INITIAL POSITION AS WELL AS MAJOR TRACK AND TRACK
SPEED DIFFERENCES AMONG THE DYNAMIC MODELS, THERE IS LOW CONFIDENCE
IN THE JTWC TRACK FORECAST.//
NNNN

[xtyphooncyclonex]

We all know there's a respective RSMC for each basin but it doesn't mean we can't question their forecasts...especially if people have evidence to back them up..



It's funny though that people themselves have their own bias...if they favor what the JTWC has forecast then they ignore the JMA warnings...same way when people favor the JMA forecast and call JTWC 'unofficial'...

Yep. I might be biased at times because I usually favor JMA's forecast as I observe that their scenarios have a higher probability of showing the actual track and occasionally intensity. But I at times prefer JTWC due to their better intensity estimate as they are not too bullish in giving intensity but may give a low forecast intensity. IMO both perform well but I'd personally go with JMA with the TRACK of Peipah. I'd go with JTWC in terms of intensity now.

[euro6208]

http://www.westernpacificweather.com/2014/04/08/tropical-storm-peipah-bagyo-domeng-update-10-tuesday-night/

Our very own meteorologist, Mike Adcock (senorpepr), gives us a thorough breakdown...

[RobWESTPACWX]

If I may step in on the "official" JMA is not the only ones who use 10min. Actually the USA is one of the only agencies that use the 1min scale. Also the only agency that uses MPH. Dosent make it right dosent make it wrong.

What I can say is according to the WMO its 10 minutes sustained for an official sustained wind report. Plus JTWC is the US military. I just dont think the United States Military should writing warnings for countries many of their forecasters have never been too. This is from a guy who was prior military as well. just a thought.

Furthermore and everytime this topic comes up and show this. I mean you can get more unnofficial than having your front page show this.

"Products on this website are intended for use by U.S. government agencies. Please consult your national meteorological agency or the appropriate World Meteorological Organization Regional Specialized Meteorological Center for tropical cyclone products pertinent to your country, region and/or local area."

With that said!

This storm was a tropical depression, and JMA truly kept it to strong I think. My opinion. Any ways not trying to poke the fire just weighing in.

Regardless its a big rain maker, if its 60 KPH or 65KPH its still going to have the same outcome. The bigger topic today I think is not intensity but where the center is, JTWC and JMA have about 150km split on where the center is.

[senorpepr]

Speaking of the split on where the center is located, this satellite image was at 00Z, along with the various met agencies "analysis" of the center of circulation. Bottom line, nobody really agrees.

[euro6208]

Remains a 30 knot depression.

WDPN31 PGTW 090300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 05W (PEIPAH) WARNING NR 25// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION (TD) 05W (PEIPAH), LOCATED APPROXIMATELY 672 NM SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED NORTHWESTWARD AT 03 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A BROAD LOW-LEVEL CIRCULATION CENTER (LLCC) WITH MULTIPLE VORTICES ROTATING ABOUT A CENTROID (WHICH IS THE INITIAL POSITION). MSI SHOWS A WEAK VORTICE NEAR 7.3N 131.4E, WHICH IS TRACKING EAST-NORTHEASTWARD AND WEAKENING OVER THE PAST SIX HOURS. DESPITE A SLIGHT IMPROVEMENT IN CONVECTIVE STRUCTURE, THE LLCC REMAINS BROAD AND THE CENTER REMAINS DIFFICULT TO PINPOINT. A 082300Z SSMIS IMAGE DEPICTS THE PRIMARY CURVED CONVECTIVE BAND OVER THE NORTHERN SEMI-CIRCLE WITH WEAK BANDING OVER THE SOUTHWEST QUADRANT AND SUPPORTS THE INITIAL POSITION WITH POOR CONFIDENCE. BASED ON THE IMPROVED, PERSISTENT BANDING AND DVORAK INTENSITY ESTIMATES OF 30 KNOTS, THE INITIAL INTENSITY IS ASSESSED AT 30 KNOTS. UPPER-LEVEL ANALYSIS REVEALS A MARGINAL ENVIRONMENT CHARACTERIZED BY MODERATE (20 KNOTS) EASTERLY VERTICAL WIND SHEAR OFFSET BY STRONG DIFFLUENCE AND GOOD POLEWARD OUTFLOW. TD 05W IS SITUATED WITHIN A WEAK STEERING ENVIRONMENT AND IS TRACKING ERRATICALLY BUT SLOWLY NORTHWESTWARD TOWARD A BREAK IN THE SUBTROPICAL RIDGE. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TD 05W IS FORECAST TO REMAIN IN THE WEAK STEERING ENVIRONMENT THROUGH TAU 36 BUT IS FORECAST TO TRACK SLOWLY NORTHWESTWARD TOWARD THE WEAKNESS IN THE SUBTROPICAL RIDGE (STR). DYNAMIC GUIDANCE IS IN FAIR AGREEMENT WITH SOLUTIONS INDICATING NORTHWESTWARD TRACKS, HOWEVER, GFS AND ECMWF NOW SHOW A QUASI-STATIONARY TRACK THROUGH TAU 48. THE JTWC FORECAST TRACK ALSO REFLECTS A VERY SLOW TRACK THROUGH TAU 48 AND IS POSITIONED CLOSE TO THE MULTI-MODEL CONSENSUS. TD 05W SHOULD SLOWLY INTENSIFY TO A PEAK OF 35 KNOTS BY TAU 36 AS THE TRACK SPEEDS INCREASE AND AS THE SYSTEM TRACKS INTO LOWER VERTICAL WIND SHEAR WHILE MAINTAINING ROBUST POLEWARD OUTFLOW. C. IN THE EXTENDED TAUS, TD 05W IS EXPECTED TO TURN WEST- NORTHWESTWARD AND TO ACCELERATE AS THE STR RE-BUILDS NORTH OF THE SYSTEM. 05W SHOULD WEAKEN GRADUALLY PRIOR TO TRACKING OVER THE PHILIPPINES AND IS FORECAST TO DISSIPATE BY TAU 96. DUE TO THE UNCERTAINTY IN THE INITIAL POSITION AND SHORT-TERM MOTION AS WELL AS MAJOR TRACK SPEED DIFFERENCES BETWEEN THE DYNAMIC MODELS, THERE IS A HIGH DEGREE OF UNCERTAINTY AND, CONSEQUENTLY, LOW CONFIDENCE IN THE JTWC TRACK FORECAST.// NNNN

[RobWESTPACWX]

Looks like JMA has a TD for Peipah now.

[wxman57]

Several weak vortices appear to be dissipating. No ASCAT but satellite seems to indicate Peipah may be weakening to a tropical wave.

[Hurricane_Luis]

ATCF explains it nicely.

W PEIPAH 140409 1800 8.2N 130.6E WPAC 25 1004

Not even worth of classification.

[xtyphooncyclonex]

No more hope for this. We will just wait for the next storms instead.

[richard-K2013]

Now, JMA just regards it as a low pressure area, but expects that it will be re-upgraded to a T.D. in the next 24 hours.

[dexterlabio]

i think it's getting decoupled...though convection is persistent, you can see a "swirl" going to the east pretty quickly via visible sat loop... looks like the mid-level circulation is leaving the system..




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