Tropical Storm SURIGAE Advisory Qua, 14-04

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 02W (SURIGAE) WARNING
NR 003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
    TROPICAL STORM 02W (SURIGAE), LOCATED APPROXIMATELY 65 NM SOUTH-
SOUTHWEST OF YAP, HAS TRACKED NORTH-NORTHWESTWARD AT 03 KNOTS OVER
THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS A
PARTIALY EXPOSED LOW LEVEL CIRCULATION CENTER, WITH THE DEEPEST
CONVECTIVE BANDING BUILDING TO THE WEST AND NORTH OF THE CENTER. THE
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A 132343Z
METOP-A ASCAT PASS SHOWING A CLEAR LLCC WITH EMBEDDED PATCHES OF 35
KNOTS. THE INTENSITY OF 35 KNOTS IS BASED ON A PGTW DVORAK FIX OF
T2.5 (35 KNOTS), ADVANCED DVORAK TECHNIQUE ESTIMATE OF 35 KNOTS AND
THE AFOREMENTIONED ASCAT PASS. ANALYSIS INDICATES A FAVORABLE
ENVIRONMENT WITH POLEWARD AND EQUATORWARD OUTFLOW CHANNELS, LOW (10-
20 KNOTS) VERTICAL WIND SHEAR, AND VERY WARM (29-30 DEGREES CELSIUS)
SEA SURFACE TEMPERATURES IN THE PHILIPPINE SEA. THE CYCLONE IS
TRACKING ALONG THE SOUTHWEST PERIPHERY OF A SUBTROPICAL RIDGE
EXTENSION LOCATED TO THE NORTHEAST.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TS 02W WILL TRACK SLOWLY NORTHWARD THEN NORTHWESTWARD OVER THE
NEXT 72 HOURS AS THE AFOREMENTIONED SUBTROPICAL RIDGE (STR)
REORIENTS. THE AFOREMENTIONED FAVORABLE ENVIRONMENT WILL MAINTAIN
AND PROMOTE STEADY INTENSIFICATION TO 85 KNOTS BY TAU 72. THERE IS A
POSSIBILITY OF INDUCED PRESSURE THAT MAY DAMPEN CONVECTION TO THE
EAST OF THE LLCC IN THE UPPER LEVELS. HOWEVER, IN TRACK GUIDANCE,
NUMERICAL MODELS ARE IN OVERALL GOOD AGREEMENT WITH A CROSS TRACK
SPREAD OF 150NM BY TAU 72 WITH THE ENSEMBLE MEAN OF ECMWF MEMBERS
TRACKING CLOSER TO THE PHILIPPINES AND JGSM SHOWING A MORE POLEWARD
TRACK, WITH THE REMAINING MODELS FALLING BETWEEN THE TWO. GIVEN THE
UNCERTAINTY IN THE INITIAL STORM MOTION, THERE IS FAIR CONFIDENCE IN
THIS PORTION OF THE JTWC TRACK FORECAST.
   C. AFTER TAU 72, TS 02W WILL CONTINUE NORTHWESTWARD TOWARD THE
BREAK IN THE RIDGE FORMED BY A MIDLATITUDE TROUGH DIGGING IN FROM
EASTERN ASIA THAT WILL BREAK THE AFOREMENTIONED STR. AFTER THE STR
BREAKS, TS 02W WILL TRACK ALONG THE WESTERN PERIPHERY OF THE STR
FEATURE POSITIONED TO ITS EAST, DRIVING IT FURTHER NORTHWESTWARD
UNTIL REACHING THE STR AXIS AROUND TAU 120. CONTINUED
INTENSIFICATION IS EXPECTED AS THE FAVORABLE CONDITIONS ARE FURTHER
ENHANCED BY INCREASED POLEWARD OUTFLOW. BY TAU 120, TS 02W IS
EXPECTED TO REACH 115 KNOTS. NUMERICAL MODELS SPREAD OUT TO OVER
300NM BY TAU 120, LENDING LOW CONFIDENCE TO THE EXTENDED PORTION OF
THE JTWC TRACK FORECAST.//
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