
[img]WDPN33 PGTW 131500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 11W (NANGKA) WARNING NR 41//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON (TY) 11W (NANGKA), LOCATED APPROXIMATELY 317 NM SOUTHWEST
OF IWO TO, HAS TRACKED NORTHWARD AT 09 KNOTS OVER THE PAST SIX
HOURS. ANIMATED ENHANCED IR IMAGERY SHOWS A CLEAR 10 NM EYE AND
OVERALL GOOD SYMMETRY IN THE CONVECTION AS WELL AS INDICATIONS OF
THE GOOD RADIAL OUTFLOW. MICROWAVE IMAGERY SHOWS THAT THE SYSTEM HAS
CONTINUED TO DEVELOP A CLEAR CUT MOAT REGION WITH SECOND EYEWALL, AN
INDICATOR THAT THE SYSTEM IS PROGRESSING THROUGH AN ERC. THE
POSITION IS BASED ON THE AFOREMENTIONED EYE WITH GOOD CONFIDENCE AND
THE INTENSITY IS HELD AT 105 KTS. UPPER LEVEL ANALYSIS INDICATES THE
SYSTEM HAS MOVED INTO AN AREA OF LOW (5 TO 10 KNOTS) VWS. THE
CYCLONE IS TRACKING ALONG THE SOUTHWESTERN SIDE OF THE STEERING STR.
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. TY 11W IS FORECAST TO TRACK POLEWARD AS THE STEERING STR BACKS
TO THE EAST AND REFORMS OVER THE NORTHWEST PACIFIC BASIN. OVER THE
NEXT 24 TO 36 HOURS, THERE MAY BE A SLIGHT EASTERN COMPONENT TO TY
11W TRACK DUE TO THE REORIENTATION OF THE STR. HOWEVER, BY TAU 48,
THE STEERING STR WILL REBUILD, FORCING TY NANGKA WEST-NORTHWESTWARD.
EXPECT CONTINUED INTENSIFICATION OF THE SYSTEM AS IT TRACKS POLEWARD
DUE TO LOW VWS AND FAVORABLE OHC THROUGH THE FORECAST WITH A PEAK OF
125 KNOTS.
C. THE EXTENDED FORECAST IS LESS CERTAIN WITH A LARGE SPREAD IN
MODEL GUIDANCE. THE GFS MODELS CONTINUE TO FAVOR A MORE EASTERN
TRACK WITH THE STR EXTENSION BUILDING IN SHARPLY, FORCING TY 11W TO
CROSS THE RIDGE AXIS JUST AFTER TAU 72 ON THE EASTERN PORTION OF
SHIKOKU. THE NAVY AND INTERNATIONAL MODELS HAVE COME INTO BETTER
AGREEMENT WITH A BROADER, WIDER, STR FORMING, WHOSE AXIS EXTENDS TO
EASTERN KYUSHU. WHILE ALL MODELS ARE IN AGREEMENT OF THE OVERALL
TRACK, THAT THE SYSTEM WILL ROUND A REBUILDING STR AXIS IN THE
EXTENDED PERIOD AND WEAKEN (DUE TO LAND INTERACTION AND INCREASED
VWS), THE EXTENT OF THE STR REBUILDING REMAINS IN QUESTION. AS SUCH,
THERE REMAINS LOW CONFIDENCE IN THE JTWC FORECAST TRACK WHICH IS
LAID SLIGHTLY WEST OF THE MULTI-MODEL CONSENSUS.//
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