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TD 07W is slow-moving and forecast to peak as a minimal tropical storm


Warning 2/JTWC


WARNING 2. FORECAST PEAK INTENSITY OF 35KNOTS WITHIN THE NEXT 24H.
WARNING 2. FORECAST PEAK INTENSITY OF 35KNOTS WITHIN THE NEXT 24H.
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WESTERN NORTH PACIFIC

TD 07W
As of 06:00 UTC Jul 25, 2019:

Location: 26.5°N 137.5°E
Maximum Winds: 30 kt ( 55km/h)
Gusts: 40 kt ( 75km/h)
Minimum Central Pressure: 1000 mb

WDPN31 PGTW 250900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION TROPICAL
DEPRESSION 07 (SEVEN) WARNING NR 002//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL DEPRESSION 07W (SEVEN), LOCATED APPROXIMATELY 540 NM
SOUTH-SOUTHWEST OF YOKOSUKA, JAPAN, HAS TRACKED NORTHWARD AT 03 KNOTS
OVER THE PAST SIX HOURS. THE CURRENT POSITION IS PLACED AT THE CENTER
OF AN EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) EVIDENT IN 250600Z
VISIBLE SATELLITE IMAGERY. THE INTENSITY OF 30 KNOTS IS HEDGED
SLIGHTLY ABOVE MULTI-AGENCY DVORAK ESTIMATES, BASED ON 250006Z AND
250032Z ASCAT PASSES INDICATING 30 KNOT WINDS NEAR THE LLCC. TD 07W
HAS TRACKED POLEWARD OVER THE PAST SIX HOURS ALONG THE PERIPHERY OF A
SUBTROPICAL RIDGE TO THE EAST. STORM MOTION HAS SLOWED TEMPORARILY
DUE TO CHANGING STEERING CONDITIONS AND POSSIBLY AS THE RESULT OF
RECENT STRUCTURAL CHANGES. PERSISTENT MODERATE TO STRONG
SOUTHWESTERLY VERTICAL WIND SHEAR (VWS) HAS LEFT THE LLCC FULLY
EXPOSED, WITH DEEP CONVECTION CONFINED TO THE EASTERN PORTION OF THE
CIRCULATION. WARM SEA SURFACE TEMPERATURES (28-29C) AND STRONG
EASTWARD AND EQUATORWARD OUTFLOW ALOFT ARE FAVORABLE FOR MARGINAL
INTENSIFICATION IN THE NEAR-TERM.
3. FORECAST REASONING.
   A. THE FORECAST TRACK THROUGH TAU 36 IS PLACED TO THE WEST OF THE
PREVIOUS FORECAST, CONSISTENT WITH A SHIFT IN THE LATEST NUMERICAL
GUIDANCE PACKAGE. HOWEVER, THIS IS NO MAJOR CHANGE TO THE FORECAST
PHILOSOPHY FROM THE PREVIOUS WARNING.
   B. TD 07W IS EXPECTED TO CONTINUE TRACKING POLEWARD THROUGH TAU 48
 AND THEN TURN EASTWARD AS IT ROUNDS THE SUBTROPICAL STEERING RIDGE
AXIS. WARM SEA SURFACE TEMPERATURES AND FAVORABLE OUTFLOW SHOULD
ALLOW THE SYSTEM TO INTENSIFY SLIGHTLY IN THE NEAR-TERM DESPITE
PERSISTENT VWS. AFTER TAU 24, INCREASING VWS AND PASSAGE OVER COOLER
WATER AND LAND WILL LEAD TO DISSIPATION. NUMERICAL MODEL GUIDANCE IS
IN GOOD AGREEMENT WITH THIS SCENARIO, AND THE CURRENT JTWC TRACK
FORECAST LIES NEAR THE MULTI-MODEL CONSENSUS THROUGH TAU 72 WITH HIGH
CONFIDENCE.
   C. TD 07W WILL CONTINUE TO DISSIPATE IN THE EXTENDED TERM, PERHAPS
SOONER. THE CIRCULATION SHOULD REMAIN SEPARATE FROM THE MID-LATITUDE
FLOW PATTERN AS IT DISSIPATES, SO EXTRATROPICAL TRANSITION IS NOT
ANTICIPATED.//
NNNN

25/0915UTC. EXPOSED CENTER
25/0915UTC. EXPOSED CENTER

25/0032UTC
25/0032UTC

TRACK AND INTENSITY GUIDANCE
TRACK AND INTENSITY GUIDANCE
Rédigé par PATRICK HOAREAU le Thursday, July 25th 2019 à 13:15