Tropical Storm LEKIMA Advisory Mon Aug 05

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 10W (LEKIMA) WARNING
NR 02//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION 10W (TEN), LOCATED APPROXIMATELY 631 NM
SOUTH-SOUTHEAST OF KADENA AB, HAS TRACKED NORTHWESTWARD AT 05 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
(MSI) REVEALS AN AREA EMBEDDED IN A BROAD CIRCULATION WHERE SUSTAINED
CONVECTION IN THE WESTERN SEMICIRCLE APPEARS TO BE CAUSING
CONSOLIDATION. THERE IS VERY LOW CONFIDENCE IN THE INITIAL POSITION,
PLACED NEAR THE APPARENT CONSOLIDATION IN THE MSI IMAGERY AND
CONSISTENT WITH A 040701Z SSMIS 91 GHZ MICROWAVE IMAGE DEPICTING A
BROAD SWATH OF DEEP CONVECTION. THE INITIAL INTENSITY OF 25 KTS IS
BASED ON RJTD AND KNES DVORAK CURRENT INTENSITY ESTIMATES OF T1.5 (25
KTS) BUT THERE HAS BEEN A LARGE AREA OF APPROXIMATELY 30 KT WESTERLY
WINDS OVER 100 NM TO THE SOUTH OF THE CURRENT POSITION WHICH IS
APPARENT ON A 070108Z METOP-C ASCAT PASS. THE ENVIRONMENT IS
FAVORABLE WITH EXCELLENT EQUATORWARD AND POLEWARD OUTFLOW, WARM
(29-30 CELSIUS) SEA SURFACE TEMPERATURE AND LOW (05-10 KT) VERTICAL
WIND SHEAR (VWS). TD 10W IS DRIFTING GENERALLY POLEWARD UNDER WEAK
STEERING INFLUENCE FROM A SUBTROPICAL RIDGE (STR) TO THE WEST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE OVERALL FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. THROUGH TAU 48, TD 10W IS EXPECTED TO DRIFT SLOWLY POLEWARD
ALONG THE EASTERN EXTENSION OF THE STR. BETWEEN TAU 48 AND 72, THE
STR EXTENSION TO THE NORTH WILL TAKE OVER AS THE PRIMARY STEERING
INFLUENCE AND THE TRACK SHOULD SHIFT MORE NORTHWESTWARD. TD 10W IS
EXPECTED TO STEADILY INTENSIFY, REACHING 55 KTS BY TAU 72. MOST OF
THE UNCERTAINTY IN THE MODEL GUIDANCE FOR THIS PORTION OF THE
FORECAST IS IN THE EARLY TAUS AS THE MODEL TRACKERS ARE LIKELY HAVING
DIFFICULTY IDENTIFYING THE LLCC IN THE BROADER CIRCULATION. AFTER TAU
12, EGRR IS THE SOUTHERN OUTLIER AND MAINTAINS A TRACK 150 NM WEST OF
CONSENSUS. OVERALL, THERE IS VERY LOW CONFIDENCE IN THE EARLY PORTION
OF THE FORECAST, LARGELY OWING TO HIGH UNCERTAINTY IN THE INITIAL
POSITION AND SUBSEQUENT UNCERTAINTY IN THE MODEL TRACK GUIDANCE.
   C. BEYOND TAU 72, TD 10W IS EXPECTED TO CONTINUE ON A
NORTHWESTWARD TRACK ALONG THE SOUTHWEST PERIPHERY OF THE STR AND TO
STEADILY INCREASE INTENSITY TO 80 KTS BY TAU 120. INTENSITY GUIDANCE
IS IN FAIR AGREEMENT THROUGHOUT THE FORECAST WITH A SPLIT OCCURRING
BETWEEN TAU 96 AND TAU 120. THE JTWC INTENSITY FORECAST IS HEDGED IN
LINE WITH THE INTENSITY CONSENSUS AS THE ENVIRONMENT APPEARS TO
REMAIN FAVORABLE FOR THE DURATION OF THE FORECAST. TRACK GUIDANCE,
WITH THE EXCEPTION OF EGRR, IS IN FAIR AGREEMENT BUT CONFIDENCE IN
THE EXTENDED FORECAST IS VERY LOW PRIMARILY DUE TO HIGH UNCERTAINTY
IN THE INITIAL POSITION.//
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