#147 Postby euro6208 » Tue Oct 23, 2018 9:50 pm
WDPN31 PGTW 240300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 31W (YUTU) WARNING
NR 11//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUPER TYPHOON (STY) 31W (YUTU), LOCATED APPROXIMATELY 177 NM EAST
OF ANDERSEN AFB, GUAM, HAS TRACKED NORTHWESTWARD AT 12 KNOTS OVER THE
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS THE
SYSTEM HAS MAINTAINED A WELL-DEFINED, ALBEIT SMALLER, 18-NM EYE AS
FEEDER BANDS WRAPPED EVEN TIGHTER INTO A HIGHLY COMPACT, DEEP, AND
MORE SYMMETRIC CENTRAL CONVECTION. THE INITIAL POSITION IS PLACED
WITH HIGH CONFIDENCE BASED ON THE EYE FEATURE THAT IS SPOT-ON WITH A
MICROWAVE EYE IN THE 232335Z AMSU PASS AND LINED UP WELL WITH A
CIRCULATION FEATURE IN A COMPOSITE RADAR LOOP FROM ANDERSEN AFB.
THE INITIAL INTENSITY OF 130 KNOTS IS BASED ON EQUIVALENT AND NEARLY
CONCENTRIC DVORAK ESTIMATE FIXES FROM PGTW AND RJTD OF T6.5/127 KNOTS
AND REFLECTS THE CONTINUED RAPID INTENSIFICATION. UPPER LEVEL
ANALYSIS INDICATES STY 31W IS IN A VERY FAVORABLE AREA WITH LOW
(10-15 KNOT) VERTICAL WIND SHEAR (VWS) AND EXCELLENT RADIAL OUTFLOW
WITH A STRONG POLEWARD BIAS. ADDITIONALLY, ALONG-TRACK SEA SURFACE
TEMPERATURES (SST) AND OCEAN HEAT CONTENT (OHC) ARE HIGHLY CONDUCIVE.
THE CYCLONE IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A
DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE NORTHEAST.
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. STY 31W IS EXPECTED TO TRACK WEST-NORTHWESTWARD UNDER THE STR
THROUGHOUT THE FORECAST. ENVIRONMENTAL CONDITIONS WILL REMAIN
FAVORABLE FOR CONTINUED INTENSIFICATION, ALBEIT AT A MORE GRADUAL
RATE TO A PEAK OF 155 KNOTS BY TAU 72. NUMERICAL MODEL GUIDANCE IS IN
GOOD AGREEMENT WITH MINIMAL SPREADING UP TO 240 NM BY TAU 72. A
NOTABLE RIGHT OF ENVELOPE OUTLIER IS HWRF. THERE IS HIGH CONFIDENCE
IN THIS PORTION OF THE JTWC TRACK FORECAST THAT IS LAID JUST LEFT OF
CONSENSUS TO OFFSET THE UNLIKELY POLEWARD TRACK OFFERED BY HWRF.
C. BEYOND TAU 72, STY YUTU WILL SLOW DOWN AS IT APPROACHES A COL
AREA AHEAD OF A MIDLATITUDE TROUGH. VWS, SST, AND OHC VALUES WILL
REMAIN FAVORABLE. HOWEVER, POLEWARD OUTFLOW WILL DIMINISH NEAR THE
COL, RESULTING IN A SLIGHT WEAKENING TO 130 KNOTS BY TAU 120. THE
NUMERICAL MODEL GUIDANCE SIGNIFICANTLY SPREADS OUT TO OVER 700 NM BY
TAU 120 WITH CTCX AND NVGM ON THE RIGHT MARGIN OF THE ENVELOPE
OFFERING A SHARP AND EARLY RECURVATURE AND EGRR AND AFUM ON THE LEFT
MARGIN OFFERING A FLAT WESTWARD TRACK. IN VIEW OF THE WIDE SPREAD,
THERE IS LOW CONFIDENCE IN THE EXTENDED PORTION OF THE JTWC TRACK
FORECAST THAT IS LAID JUST LEFT OF AND SLOWER THAN CONSENSUS TO
OFFSET THE UNLIKELY SHARP POLEWARD RECURVATURE OFFERED BY CTCX AND
NVGM.//N
NNNN
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Remember, all of my post aren't official. For official warnings and discussions, Please refer to your local NWS products...
NWS for the Western Pacifichttps://www.weather.gov/gum/
