WPAC: NORU - Low

[gatorcane]

Wow I have never seen models go that low with pressure before.

[doomhaMwx]

Strong typhoons this far north hitting Japan is very rare but can sometimes happen.

The lowest ever pressure observed in a landfalling typhoon happened way back in 1934's Muroto typhoon. Pressure recorded was 911.9 mb and was the world record holder for most intense TC to make landfall until broken the following year.

I remember back in the 90s a storm named Yancy hit Kyusho Island and pressures in the 930s were measured at landfall.

Those two that you mentioned occurred in late August and/or in September...
Some others I can think of that hit Mainland Japan as strong/intense Typhoons are Ida(1958) and Vera(1959), both also occurred in September...

I read somewhere that strong/intense Typhoons that far north typically occur in September...

[dexterlabio]

Such intense landfall intensity was also forecast with Typhoon Lionrock last year. Models were really bullish, JMA also forecast a violent typhoon (10-min average winds >100kts) touchdown in Japan. It made landfall as a strong tropical storm.

[wxman57]

The global models have a tough time forecasting intensity/pressure in the subtropics. They're almost always way too strong.

[shah83]

Does need to be said the HWRF, which was earlier downplaying the low pressures, are more recently predicting a huge cat 4, like this 06z run.

[NotoSans]

Basically 0% chance that solutions from the global models will materialize. Global models ALWAYS over-intensify systems over the subtropics. The problem becomes worse if the systems are forecast to remain stationary over some sufficiently warm water, such as over the Kuroshio Current, because global models don't decrease SSTs over time.

[euro6208]

WDPN31 PGTW 012100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 07W (NORU) WARNING NR
49//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON 07W (NORU), LOCATED APPROXIMATELY 484 NM EAST OF KADENA AB,
OKINAWA, HAS TRACKED NORTHWESTWARD AT 07 KNOTS OVER THE PAST SIX
HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS DEEP
CONVECTION BANDING INTO A VERY WIDE, 50 NM WIDE EYE FEATURE. THE
EYEWALL HAS WEAKENED SOMEWHAT WITH A MINOR BREAK IN THE NORTHWESTERN
QUADRANT OF THE SYSTEM. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON THE LARGE EYE FEATURE. A 011218Z METOP-B AMSU 89
GHZ MICROWAVE IMAGE LENDS HIGH CONFIDENCE TO THE ASSESSED POSITION
AND CONFIRMS THAT MODERATE TO DEEP CONVECTION IS EVENLY DISTRIBUTED
AROUND THE EYE. THE INITIAL INTENSITY IS SET AT 90 KNOTS, ON THE
HIGH END OF SUBJECTIVE DVORAK OF MULTI-AGENCY DVORAK INTENSITY
ESTIMATES OF T4.5 TO T5.0 (77 TO 90 KNOTS) AS WELL AS OBJECTIVE
SATELLITE CONSENSUS (SATCON) AND ADVANCED DVORAK TECHNIQUE (ADT)
ESTIMATES OF 87 KNOTS. ENVIRONMENTAL ANALYSIS REVEALS THAT THE
SYSTEM IS LOCATED IN A GENERALLY FAVORABLE AREA WITH LOW (5-10
KNOTS) VERTICAL WIND SHEAR (VWS) AND HIGH SEA SURFACE TEMPERATURES
(SSTS) OF 30-31 DEGREES CELSIUS. TY 07W IS ISOLATED FROM ANY WELL
DEFINED OUTFLOW CHANNELS, BUT HAS A DISTINCT UPPER-LEVEL POINT
SOURCE OVER TOP OF THE LLCC, PROVIDING MODERATE LEVELS OF RADIAL
OUTFLOW OFFSETTING THE HIGH OHC AND LOW VWS AND HELPING TO KEEP THE
INTENSITY STEADY AT 90 KNOTS. TY 07W REMAINS IN A COMPLEX AND
COMPETING STEERING ENVIRONMENT, UNDER THE INFLUENCE OF DEEP-LAYER
RIDGES TO THE SOUTHWEST, SOUTHEAST, AND NORTHWEST. THE PRIMARY
STEERING REMAINS THE NEAR EQUATORIAL RIDGE (NER) LOCATED TO THE
SOUTHEAST.
3. FORECAST REASONING.
A. NO CHANGE TO THE FORECAST TRACK PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. TY 07W IS FORECAST TO TRACK NORTHWESTWARD AND TURN SLIGHTLY
NORTH-NORTHWESTWARD THROUGH TAU 24, AS AN MID-LATITUDE TROUGH
CURRENTLY JUST EAST AND SOUTH OF HONSHU DIGS SLIGHTLY FURTHER SOUTH
AND WEAKENS THE RIDGE TO THE NORTH. THIS SLIGHT TURN POLEWARD WILL
BE SHORT LIVED, AS THE TROUGH QUICKLY MOVES OUT TO THE NORTHEAST BY
TAU 36. AS THE TROUGH EXITS THE AREA, AN EXTENSION OF THE
SUBTROPICAL RIDGE (STR) OVER KOREA WILL BUILD IN TO THE NORTH OF TY
07W, PUSHING IT BACK ONTO A WEST-NORTHWESTWARD TRACK. THIS NORTHERN
RIDGE REMAINS THE PRIMARY STEERING MECHANISM THROUGH TAU 72. TY 07W
IS FORECAST TO WEAKEN SLIGHTLY OVER THE NEXT 12 HOURS AS IT
PROGRESSES OF A POOL OF COOLER WATERS WHILE MAINTAINING WEAK OUTFLOW
PROVIDED BY THE UPPER-LEVEL POINT SOURCE. BY TAU 24, THE SYSTEM WILL
AGAIN INTENSIFY SLIGHTLY AS IT TAPS INTO A POLEWARD OUTFLOW CHANNEL
ALONG THE EASTERN EDGE OF THE MID-LATITUDE TROUGH. THE SYSTEM AGAIN
WEAKENS SLIGHTLY BY TAU 48 AS IT AGAIN BECOMES ISOLATED FROM ANY
OUTFLOW CHANNELS. GRADUAL STRENGTHENING IS AGAIN EXPECTED AFTER TAU
48, AS A VERY STRONG UPPER-LEVEL ANTICYCLONE IS EXPECTED TO DEVELOP
OVER THE SYSTEM, PROVIDING ROBUST RADIAL OUTFLOW, COINCIDENT WITH
THE PASSAGE OF THE SYSTEM OVER VERY WARM (31 DEG CELSIUS) WATERS
WITH HIGH OHC VALUES. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT
THROUGH TAU 72, WITH NAVGEM AND JGSM DEFINING THE SOUTH AND WESTERN
OUTLIERS, AND GFS AND HWRF DEFINING THE EASTERN AND NORTHERN EDGE OF
THE MODEL ENVELOPE. ALL MODELS ARE IN AGREEMENT IN THE TRACK
SCENARIO THROUGH TAU 72 AND THERE IS OVERALL HIGH CONFIDENCE IN THIS
PORTION OF THE FORECAST TRACK.
C. BY AROUND TAU 72, THE RIDGE LOCATED TO THE NORTH OF THE SYSTEM
BEGINS TO WEAKEN AND RECEDE EASTWARD IN RESPONSE TO THE APPROACH OF
A DEEPENING MID-LATITUDE TROUGH MOVING INTO THE AREA FROM THE
NORTHWEST. TY 07W WILL SLOW SLIGHTLY BEFORE TURNING TO THE NORTH
AFTER TAU 96, AS THE RIDGE TO THE NORTH BREAKS DOWN. TYPHOON NORU
WILL CONTINUE TO STRENGTHEN THROUGH TAU 96, AS IT TAPS INTO THE
POLEWARD OUTFLOW CHANNEL AHEAD OF THE APPROACHING TROUGH. THE
SYSTEM WEAKENS SLIGHTLY BY TAU 120 AS IT COMES UNDER THE INFLUENCE
OF INCREASING VWS. ALL AVAILABLE MODELS AGREE ON THE OVERALL TRACK
SCENARIO BUT HAVE SIGNIFICANT DIFFERENCES IN THE TIMING AND STRENGTH
OF THE TURN. ALTERNATE SCENARIOS INCLUDE THE GFS SOLUTION OF A TURN
TO THE NORTHEAST AT TAU 72, WITH A TRACK NORTHEAST PARALLEL TO THE
COAST OF THE JAPANESE ISLANDS, OR THE NAVGEM AND ECMWF SOLUTION,
WHICH KEEPS THE SYSTEM ON THE WESTWARD TRACK THROUGH TAU 96 TO JUST
NORTH OF OKINAWA BEFORE TURNING NORTH. DUE TO THE BROAD MODEL SPREAD
AND POTENTIAL ALTERNATE SCENARIOS, THERE IS OVERALL LOW CONFIDENCE
IN THE FORECAST TRACK.//
NNNN

[euro6208]

NAVGEM and EURO agrees on a track between South Korea and Japan while GFS still wants Japan. All show strengthening while on approach. Here GFS peaks it at...865 mb...

[euro6208]

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.2.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 01 AUG 2017 Time : 203000 UTC
Lat : 25:13:22 N Lon : 136:29:07 E


CI# /Pressure/ Vmax
5.1 / 960.0mb/ 92.4kt


Final T# Adj T# Raw T#
5.1 5.3 5.3

Estimated radius of max. wind based on IR : 62 km

Center Temp : +16.1C Cloud Region Temp : -62.6C

Scene Type : LARGE EYE

Positioning Method : SPIRAL ANALYSIS

Ocean Basin : WEST PACIFIC
Dvorak CI > MSLP Conversion Used : CKZ Method

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : N/A
- Environmental MSLP : 1008mb

Satellite Name : HIM-8
Satellite Viewing Angle : 29.9 degrees

****************************************************

[mrbagyo]

Noru has become a classic annular typhoon
Truck tire donut with a huge eye.

[mrbagyo]

[Digital-TC-Chaser]

Nice link sat updates every 15 min.
http://quicklooks.cr.chiba-u.ac.jp/~him ... index.html

[mrbagyo]

Has there been any tropical cyclone before that went from being a Big eyed annular into a pinhole compact?

[wxmann_91]

Has there been any tropical cyclone before that went from being a Big eyed annular into a pinhole compact?

Probably not. Pinhole storms form in relatively high-SST, high-instability environments. Big eyed annular storms form in relatively low-SST, low-instability environments. It's easy to go from the former to the latter, but unusual to go in the opposite direction.

[CrazyC83]

I don't get what the global models are seeing.

How could a storm structured like this - with an RMW likely over 50 nautical miles - manage to go into rapid deepening to a storm that challenges world records for pressure? I can't see how such is possible, no matter how much baroclinic forcing is involved. The most intense storms tend to be much smaller in terms of their cores with much deeper cloud tops. I do agree the pressure should be much lower than the wind would suggest (right now I would estimate it at 85 kt, but the pressure around 946).

Also the size seems insane on the forecast models - it would be much bigger than Texas. Not quite Sandy-sized, but close.

[Digital-TC-Chaser]

https://www.youtube.com/watch?v=9Rh_y1HnqWU
Westpacwx Update by Robert Speta. As always excellent.

[doomhaMwx]

6 named storms have already formed/developed in the NW Pacific while Noru is still active (the 6th one is Nalgae), which is a new record according to Digital-Typhoon...

[euro6208]

WDPN31 PGTW 020300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 07W (NORU) WARNING NR
50//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON 07W (NORU), LOCATED APPROXIMATELY 463 NM EAST OF KADENA
AB, OKINAWA, HAS TRACKED NORTHWESTWARD AT 05 KNOTS OVER THE PAST SIX
HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A MUCH MORE
SYMMETRIC SYSTEM WITH A RING OF CONVECTION HAVING COMPLETELY
SURROUNDED THE WELL-DEFINED EYE, WHICH HAS GENERALLY DECREASED IN
RADIUS FROM 50 NM TO APPROXIMATELY 30 NM IN THE PAST SIX HOURS. THE
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EYE
FEATURE. THE INITIAL INTENSITY HAS BEEN INCREASED TO 105 KNOTS, ON
THE UPPER END OF SUBJECTIVE DVORAK CURRENT INTENSITY ESTIMATES T5.0
AND T5.5 (90 TO 102 KNOTS) FROM KNES AND PGTW RESPECTIVELY. THE
LATEST OBJECTIVE SATELLITE CONSENSUS INTENSITY ESTIMATES ARE IN THE
100 TO 105 KNOT RANGE AS WELL. A 012209Z SSMIS 91 GHZ MICROWAVE
IMAGE SHOWS THE CORE COMPLETELY SURROUNDED BY A CIRCULAR RING OF
DEEP CONVECTION WITH LITTLE TO NO CONVECTIVE BANDING IN EVIDENCE.
ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE WITH LOW (5 TO 10 KNOTS)
VERTICAL WIND SHEAR (VWS) AND HIGH SEA SURFACE TEMPERATURES (SSTS)
NEAR 30 DEG CELSIUS. OUTFLOW HAS IMPROVED SIGNIFICANTLY AS THE POINT
SOURCE ABOVE THE SYSTEM HAS DEVELOPED MORE THAN ANTICIPATED. TY 07W
IS TRACKING NORTHWESTWARD ALONG THE WESTERN BOUNDARY OF A DEEP NEAR-
EQUATORIAL TROUGH TO THE EAST AND TOWARDS A WEAKNESS IN THE
SUBTROPICAL RIDGE (STR) TO THE NORTH CAUSED BY PASSAGE OF A MID-
LATITUDE TROUGH.
3. FORECAST REASONING.
A. NO CHANGE TO THE FORECAST TRACK PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. TY 07W IS FORECAST TO TRACK NORTHWESTWARD UNDER THE INFLUENCE
OF THE NER TO THE SOUTHEAST AND IN RESPONSE TO THE DEVELOPMENT OF A
WEAKNESS IN THE RIDGE TO THE NORTH, BROUGHT ABOUT BY THE PASSAGE OF
THE PREVIOUSLY MENTIONED MID-LATITUDE TROUGH. THE TRACK IS FORECAST
TO FLATTEN OUT AND BECOME MORE WEST-NORTHWEST AFTER TAU 36, AS THE
TROUGH PASSES BY AND AN EXTENSION OF THE STR OVER KOREA BUILDS IN TO
THE NORTH OF THE SYSTEM. TY 07W IS FORECAST TO INTENSIFY OVER THE
NEXT 24 HOURS, PEAKING AT 115 KNOTS, AS IT REMAINS IN A LOW VWS
ENVIRONMENT AND TRANSITS OVER HIGH SSTS AND TAPS INTO A ROBUST
POLEWARD OUTFLOW CHANNEL AT THE BASE OF THE APPROACHING TROUGH.
BETWEEN TAUS 24 AND 48 THE SYSTEM IS FORECAST TO WEAKEN AS
NORTHWESTERLY FLOW ALOFT PROVIDES PRESSURE TO THE SYSTEM AND
DECREASES AVAILABLE OUTFLOW. ANOTHER ROUND OF INTENSIFICATION IS
EXPECTED BETWEEN TAUS 48 AND 72 AS THE SYSTEM DEVELOPS A STRONG
ANTICYCLONE ALOFT AND TAPS INTO AN EQUATORWARD OUTFLOW CHANNEL,
WHILE MOVING OVER THE KUROSHIO CURRENT WITH WATERS AT OR EXCEEDING
31 DEG CELSIUS. MODEL GUIDANCE HAS COME INTO VERY GOOD AGREEMENT ON
THE TRACK THROUGH TAU 72, WITH NAVGEM AND GFS BEING THE SOUTHERN AND
NORTHERN OUTLIERS RESPECTIVELY. WITH THE IMPROVED MODEL AGREEMENT ON
THE OVERALL TRACK AND DECREASING SPREAD, THERE IS HIGH CONFIDENCE IN
THIS PORTION OF THE FORECAST TRACK.
C. BY AROUND TAU 72, THE RIDGE LOCATED TO THE NORTH OF THE SYSTEM
BEGINS TO WEAKEN AND RECEDE EASTWARD IN RESPONSE TO THE APPROACH OF
A DEEPENING MID-LATITUDE TROUGH MOVING INTO FROM THE NORTHWEST. TY
07W WILL SLOW SLIGHTLY BEFORE TURNING TO THE NORTH AND THEN NORTH-
NORTHEAST AFTER TAU 96, AS THE RIDGE TO THE NORTH BREAKS DOWN.
TYPHOON NORU WILL STEADILY INTENSIFY FROM TAU 72 THROUGH 96, PEAKING
AT 120 KNOTS AS IT CONTINUES TO BE SUPPORTED BY STRONG RADIAL
OUTFLOW AND HIGH SSTS ACCOMPANIED BY LOW VWS. AS THE SYSTEM
APPROACHES THE WESTERN PORTION OF KYUSHU BY TAU 120, IT IS FORECAST
TO BEGIN A WEAKENING TREND AS THE WIND FIELD INTERACTS WITH TERRAIN,
SSTS BEGIN TO DROP AND VWS INCREASES. ALL MODELS AGREE ON THE
OVERALL TRACK BUT STILL WITH VARIANCES IN THE TIMING AND STRENGTH OF
THE TURN. GFS AND THE GFS VERSION OF COAMPS-TC AREA NOW THE SOLE
OUTLIERS TURNING THE SYSTEM NORTHEASTWARD TO THE EAST OF THE MAIN
JAPANESE ISLANDS BY TAU 96, WITH THE REMAINDER OF THE CONSENSUS
MEMBERS TURNING THE SYSTEM NORTH AFTER PASSING THE RYUKUS. WITH THE
DECREASING SPREAD IN THE MODEL GUIDANCE, THERE IS INCREASING, BUT
LOW CONFIDENCE IN THE FORECAST TRACK.//
NNNN

[doomhaMwx]

Absolutely amazing photos of TY Noru captured by astronauts from the Int'l Space Station(ISS) yesterday(Aug 1, 2017)!
http://www.businessinsider.com/typhoon- ... res-2017-8

 https://twitter.com/AstroKomrade/status/892475089819639808



 https://twitter.com/Astro2fish/status/892410268541530112



 https://twitter.com/SergeyISS/status/892371612569415684

[Digital-TC-Chaser]

102hrs EC/GFS.







07W NORU 170802 0600 25.9N 135.9E WPAC 100 947
Aug 02, 2017 8:05 pm