#217 Postby euro6208 » Sun Sep 09, 2018 4:51 pm
Still expecting a major to pass through.
WDPN31 PGTW 092100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 26W (MANGKHUT) WARNING NR 12//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON (TY) 26W (MANGKHUT), LOCATED APPROXIMATELY 252 NM EAST-
NORTHEAST OF ANDERSEN AFB, GUAM, HAS TRACKED WEST-SOUTHWESTWARD AT
18 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY DEPICTS A SLOWLY CONSOLIDATING SYSTEM WITH TIGHTLY-
CURVED BANDING (TCB) WRAPPING INTO A WELL-DEFINED LOW-LEVEL
CIRCULATION CENTER. THERE IS GOOD CONFIDENCE IN THE CURRENT POSITION
BASED ON A 091726Z SSMI 85GHZ IMAGE AND A 091818Z MHS 89GHZ IMAGE,
WHICH BOTH SHOW TCB WRAPPING INTO A WELL-DEFINED CENTER. THE SYSTEM
IS JUST BEGINNING TO MOVE WITHIN THE ANDERSEN AFB RADAR RANGE,
HOWEVER, THE CENTER IS CURRENTLY AT A DISTANCE OF 225NM AND THE
RADAR BEAM HEIGHT IS AT 45,000 FEET. THE CURRENT INTENSITY IS
ASSESSED AT 80 KNOTS BASED ON DVORAK ESTIMATES OF T4.5 (77 KNOTS)
FROM ALL AGENCIES, AND A RECENT (091545Z) SATCON ESTIMATE OF 76
KNOTS. UPPER-LEVEL ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH
LOW VERTICAL WIND SHEAR AND ROBUST RADIAL OUTFLOW. ADDITIONALLY, SST
AND OCEAN HEAT CONTENT VALUES REMAIN CONDUCIVE FOR FURTHER
INTENSIFICATION. TY 26W IS TRACKING QUICKLY WEST-SOUTHWESTWARD ALONG
THE SOUTHERN PERIPHERY OF A DEEP-LAYERED, STRONG SUBTROPICAL RIDGE
(STR) ENTRENCHED TO THE NORTH.
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY FROM THE
PREVIOUS WARNING.
B. THROUGH TAU 48, THE STR TO THE NORTH IS EXPECTED TO CONTINUE
STEERING 26W GENERALLY WEST-SOUTHWESTWARD TO WESTWARD (255-270
RADIAL). DYNAMIC MODEL GUIDANCE IS IN TIGHT AGREEMENT WITH A SPREAD
OF 38NM AT TAU 12 NEAR GUAM. DUE TO THE SYSTEM SIZE (APPROXIMATELY
370-NM DIAMETER) AND EXPANSIVE SPIRAL BANDING, THE SYSTEM IS
EXPECTED TO HAVE A MAJOR IMPACT OVER A LARGE AREA. TY 26W IS
FORECAST TO INTENSIFY THROUGH TAU 24 TO AN INTENSITY RANGING FROM 95
TO 105 KNOTS. AFTER TAU 24, TY 26W WILL CONTINUE TO INTENSIFY TO A
PEAK OF 125 KNOTS BY TAU 72. THE CURRENT TRACK REMAINS HIGHLY
CONSISTENT WITH THE PREVIOUS WARNING AND IS POSITIONED CLOSE TO THE
MULTI-MODEL CONSENSUS UNTIL THERE IS SUFFICIENT EVIDENCE TO SUPPORT
A SIGNIFICANT SHIFT IN THE TRACK CLOSER TO GUAM.
C. AFTER TAU 72, TY 26W WILL TURN WEST-NORTHWESTWARD ALONG THE
SOUTHWEST PERIPHERY OF THE STR, WHICH IS EXPECTED TO ERODE IN
RESPONSE TO AN APPROACHING MIDLATITUDE TROUGH. TRACK GUIDANCE
REMAINS IN GOOD AGREEMENT FOR THIS PORTION OF THE FORECAST TRACK
WITH A 150NM SPREAD IN SOLUTIONS AT TAU 120. BASED ON THE FAVORABLE
ENVIRONMENT, THE INTENSITY IS FORECASTED TO PEAK AT SUPER TYPHOON
STRENGTH AT TAU 96 WITH SLIGHT WEAKENING AS THE SYSTEM INTERACTS
WITH LUZON NEAR TAU 120. OVERALL CONFIDENCE IN THE JTWC FORECAST
TRACK IS HIGH BASED ON THE TIGHT GROUPING OF NUMERICAL MODEL
GUIDANCE.//
NNNN
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