Tropical Storm MAYSAK Advisory Fri Mar 27

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 04W (FOUR) WARNING
NR 01//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 04W (FOUR), LOCATED APPROXIMATELY 13 NM
WEST-SOUTHWEST OF POHNPEI, HAS TRACKED WESTWARD AT 08 KNOTS OVER THE
PAST SIX HOURS. THE CURRENT POSITION IS BASED ON A 262330Z ASCAT
PASS AND COINCIDENT METOP-A 89 GHZ MICROWAVE SATELLITE IMAGE. THE
INTENSITY OF 25 KNOTS IS BASED ON THE ASCAT DATA AND A CONSENSUS OF
DVORAK SATELLITE INTENSITY ESTIMATES FROM PGTW, KNES, AND RJTD. TD
04W HAS CONSOLIDATED OVER THE PAST SEVERAL HOURS, WITH NEWLY-FORMED
DEEP CONVECTIVE BANDING WRAPPING INTO THE LOW LEVEL CIRCULATION
CENTER (LLCC). THE SYSTEM IS TRACKING WESTWARD ALONG THE SOUTHERN
PERIPHERY OF AN EXTENSIVE SUBTROPICAL STEERING RIDGE.  STRONG
DIVERGENCE ALOFT IS SUPPORTING DEVELOPMENT OF THE CIRCULATION,
DESPITE MODERATE EASTERLY VERTICAL WIND SHEAR OBSERVED OVER THE LLCC.
3. FORECAST REASONING.
   A. THIS IS THE INITIAL PROGNOSTIC REASONING AND SETS THE FORECAST
PHILOSOPHY.
   B. TD 04W WILL CONTINUE TRACKING ALONG THE SOUTHERN PERIPHERY OF
THE CURRENT STEERING RIDGE THROUGH TAU 72.  DYNAMIC MODEL GUIDANCE
IS IN GOOD AGREEMENT WITH THE FORECAST TRACK, WITH ONLY THE NAVGEM
MODEL DEPICTING A TRACK SLIGHTLY FARTHER TO THE NORTH OF THE PRIMARY
MODEL GROUPING.  GIVEN THE STRAIGHTFORWARD STEERING SCENARIO AND
TIGHT MODEL AGREEMENT, THERE IS HIGH CONFIDENCE IN THE TRACK
FORECAST THROUGH TAU 72. STEADY INTENSIFICATION IS ANTICIPATED DUE
TO STRONG DIFFLUENCE ALOFT AND PASSAGE OVER VERY WARM WATER. THE
INTENSIFICATION RATE SHOULD BE LIMITED SOMEWHAT BY CONTINUED
EASTERLY VERTICAL WIND SHEAR, PARTICULARLY EARLY IN THE FORECAST
PERIOD.
   C. AFTER TAU 72, WEST-NORTHWESTWARD MOTION IS EXPECTED TO
CONTINUE AS TD 04W TRACKS ALONG THE SUBTROPICAL RIDGE PERIPHERY.
STEADY INTENSIFICATION IS ALSO ANTICIPATED AS VERTICAL WIND SHEAR
DECREASES AND OTHER FAVORABLE FACTORS REMAIN IN PLACE. THE DYNAMIC
MODEL GUIDANCE REMAINS IN FAIRLY GOOD AGREEMENT THROUGH TAU 120,
LENDING HIGH CONFIDENCE TO THE EXTENDED FORECAST TRACK.//
NNNN
NNNN