Tropical Storm USAGI Advisory mar, 20-11

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 33W (THIRTYTHREE)
WARNING NR 05//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 33W (THIRTYTHREE), LOCATED APPROXIMATELY
679 NM EAST-SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-
NORTHWESTWARD AT 14 KNOTS OVER THE PAST SIX HOURS. ANIMATED
MULTISPECTRAL SATELLITE IMAGERY CONTINUES TO DEPICT AN ELONGATED,
EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH A SMALL AREA OF
FLARING CONVECTION OVER THE WEST QUADRANT AND A LARGER, MORE
PERSISTENT AREA OF DEEP CONVECTION SHEARED OVER THE NORTHWEST
PERIPHERY. A 190729Z F-16 SSMIS 37H GHZ IMAGE DEPICTS WEAKLY CURVED
DEEP CONVECTIVE BANDING OVER THE WEST QUADRANT ASSOCIATED WITH THE
SMALL AREA OF FLARING CONVECTION AND GENERALLY BROAD, SHALLOW
BANDING WRAPPING INTO THE ELONGATED LLCC. TD 33W CONTINUES TO SLOWLY
DEVELOP DUE TO MODERATE TO STRONG (20 TO 30 KNOTS) EASTERLY VERTICAL
WIND SHEAR (VWS) OFFSET BY BROAD DIFFLUENT FLOW AND WARM SST (28-
29C). DVORAK INTENSITY ESTIMATES HAVE REMAINED FLAT AT T1.5 (25
KNOTS), HOWEVER, THE INITIAL INTENSITY REMAINS ASSESSED SLIGHTLY
HIGHER AT 30 KNOTS BASED ON RECENT ASCAT IMAGERY SHOWING 25 TO 30
KNOT WINDS. TD 33W IS TRACKING UNDER THE STEERING INFLUENCE OF THE
LOW- TO MID-LEVEL SUBTROPICAL RIDGE (STR) POSITIONED TO THE
NORTH.
3. FORECAST REASONING.
   A.  THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TD 33W IS EXPECTED TO TRACK WEST-NORTHWESTWARD TO WESTWARD
THROUGH TAU 72 AS IT TRACKS ALONG THE SOUTHERN PERIPHERY OF THE
STR. TD 33W SHOULD INTENSIFY SLOWLY THROUGH TAU 72 AS IT CONTINUES
TO STRUGGLE IN MARGINAL CONDITIONS AND CROSSES THE PHILIPPINES.
NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT WITH A SPREAD OF 175NM
IN SOLUTIONS AT TAU 72.
   C. AFTER TAU 72, TD 33W WILL TRACK WESTWARD WHILE TRANSITIONING
TO THE STEERING INFLUENCE OF THE WESTERN STR. THERE IS INCREASING
UNCERTAINTY WITH SIGNIFICANT DIFFERENCES IN TRACK SPEED AND THE
TIMING OF LANDFALL OVER EASTERN VIETNAM. HOWEVER, THE JTWC
FORECAST TRACK FAVORS A FLATTER TRACK AND IS POSITIONED ON THE
SOUTHERN EDGE OF THE AIDS ENVELOPE CLOSER TO THE ECMWF SOLUTION. TD
33W SHOULD REINTENSIFY TO A PEAK OF 55 KNOTS BY TAU 96 UNDER
MARGINALLY-FAVORABLE CONDITIONS CHARACTERIZED BY IMPROVED POLEWARD
OUTFLOW AND SLIGHTLY LOWER VALUES OF VWS. OVERALL, THERE IS LOW
CONFIDENCE IN THE JTWC FORECAST TRACK.//
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