CLICK TO ANIMATE. TC 04P
Location: 13.9°N 117.6°E
Maximum Winds: 75 kt ( 140km/h)
Gusts: 90 kt ( 170km/h)
Minimum Central Pressure: mb
CATEGORY US: 1
WDPN31 PGTW 261500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 30W (PHANFONE) WARNING NR 020//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON (TY) 30W (PHANFONE), LOCATED APPROXIMATELY 554 NM EAST-
SOUTHEAST OF DA NANG, VIETNAM, HAS TRACKED NORTHWESTWARD AT 06 KNOTS
(KTS) OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY REVEALS THE EYE HAS FILLED AND CLOUD TOP TEMPERATURES
ARE WARMING. THERE IS FAIR CONFIDENCE IN THE INITIAL POSITION USING A
COMBINATION OF THE EIR AND A 260932Z AMSU 89 GHZ MICROWAVE IMAGE. THE
INITIAL INTENSITY IS ON THE LOW SIDE OF PGTW/RJTD DVORAK INTENSITIES OF
T4.5-5.0 (77-90 KTS) TO REFLECT THE WEAKENED CONVECTIVE SIGNATURE. FAIR
POLEWARD OUTFLOW, MODERATE (15-20 KT) VERTICAL WIND SHEAR, AND WARM (27-
28 CELSIUS) SEA SURFACE TEMPERATURE SUGGEST THE ENVIRONMENT IS
FAVORABLE; HOWEVER, THERE IS DRY AIR ENTRAINING IN FROM THE WEST THAT IS
LIKELY MAKING THE ENVIRONMENT UNFAVORABLE OVERALL. TY 30W IS TRACKING
ALONG THE SOUTHWEST PERIPHERY OF A SUBTROPICAL RIDGE (STR).
3. FORECAST REASONING.
A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. TY 30W WILL CONTINUE ON A WEST-NORTHWESTWARD TO NORTHWESTWARD
TRACK UNTIL TAU 72 WHEN IT DISSIPATES DUE TO DRY AIR ENTRAINMENT AND
HIGH VWS. SPREAD IN THE MODEL GUIDANCE REACHES OVER 380 NM BY TAU 72,
WITH UKMET BEING THE SOUTHERNMOST MEMBER AND NAVGEM BEING THE
NORTHERNMOST. THE JTWC TRACK FORECAST IS HEDGED NORTH OF CONSENSUS WITH
LOW CONFIDENCE.//
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Location: 14.4°S 175.8°E
Maximum Winds: 45 kt ( 85km/h)
Gusts: 55 kt ( 100km/h)
REMARKS:
261500Z POSITION NEAR 14.9S 175.8E.
26DEC19. TROPICAL CYCLONE (TC) 04P (SARAI), LOCATED APPROXIMATELY 268
NM NORTHWEST OF SUVA, FIJI, HAS TRACKED SOUTHWARD AT 12 KNOTS (KTS)
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
REVEALS ISOLATED CENTRAL CONVECTION AND A LARGE RAIN BAND TO THE EAST
OF THE LOW LEVEL CIRCULATION (LLC). THERE IS FAIR CONFIDENCE IN THE
INITIAL POSITION, PLACED USING A 260942Z METOP-B ASCAT PARTIAL PASS
SHOWING AN ELONGATED LLC WITH 35 KT WINDS TO THE SOUTH. THE ASCAT PASS
FAILS TO PROVIDE COVERAGE OF THE EASTERN HALF OF THE LLC. THE INITIAL
INTENSITY IS CONSISTENT WITH PGTW/KNES DVORAK FIX INTENSITIES OF T3.0
(45 KTS). EXCELLENT POLEWARD OUTFLOW, MODERATE (15-20 KT) VERTICAL
WIND SHEAR (VWS), AND WARM (29-30 CELSIUS) SEA SURFACE TEMPERATURE
MAKE THE ENVIRONMENT FAVORABLE OVERALL. TC 04P IS TRACKING ALONG THE
WESTERN PERIPHERY OF A POLEWARD EXTENSION OF A NEAR EQUATORIAL RIDGE
(NER). AROUND TAU 24 WHEN TC 04P IS WEST OF NADI, FIJI, THE TRACK WILL
GRADUALLY SHIFT EASTWARD AS THE NER REORIENTS. BY TAU 48, THE TRACK
WILL BE EASTWARD TO EAST-SOUTHEASTWARD, WHERE IT WILL REMAIN UNTIL TAU
120. THE FAVORABLE ENVIRONMENT SHOULD SUPPORT SLOW, STEADY
INTENSIFICATION THROUGH TAU 48. AT THAT POINT, VWS SHOULD INCREASE AND
THE INTENSITY SHOULD SLOWLY WEAKEN. WITH THE EXCEPTION OF TWO SLIGHT
SOUTHERN OUTLIERS (GFS AND GFS ENSEMBLE MEAN), TRACK GUIDANCE IS IN
GOOD AGREEMENT. THE JTWC TRACK FORECAST IS HEDGED JUST NORTH OF THE
CONSENSUS TRACK TO OFFSET THE INFLUENCE OF THE GFS OUTLIERS WITH FAIR
CONFIDENCE. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 261200Z IS 21 FEET.
NEXT WARNINGS AT 262100Z, 270300Z, 270900Z AND 271500Z.//
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