Tropical Storm SAOLA Advisory Wed Oct 25

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 27W (TWENTYSEVEN)
WARNING NR 19//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM 27W (TWENTYSEVEN), LOCATED APPROXIMATELY 159 NM
WEST OF NAVSTA GUAM, HAS TRACKED NORTHWESTWARD AT 25 KNOTS OVER
THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI)
SHOWS THE MAIN CONVECTION HAS SHEARED SOUTHWESTWARD OF A PARTIALLY
EXPOSED, BROAD, LOW LEVEL CIRCULATION CENTER (LLCC). A 240206Z
89GHZ GMI MICROWAVE IMAGE CONFIRMS THAT THE DEEP CONVECTION IS
SHEARED TO THE SOUTHWEST OF THE LLCC. ADDITIONALLY, A 240031Z
METOB-B ASCAT IMAGE REVEALS THE LOW LEVEL CIRCULATION TO BE HIGHLY
ELONGATED. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE
BASED ON THE PARTIALLY EXPOSED LLCC EVIDENT IN THE ANIMATED MSI.
THE INITIAL INTENSITY OF 40 KNOTS IS HEDGED ABOVE MULTI AGENCY
DVORAK INTENSITY ESTIMATES RANGING FROM T2.0 TO T2.5 (30-35 KNOTS)
FROM RJTD AND PGTW RESPECTIVELY AND IS SUPPORTED BY A SATCON
ESTIMATE OF 41 KNOTS. ENVIRONMENTAL ANALYSIS REVEALS THAT THE
SYSTEM IS TRACKING THROUGH WARM (31 CELSIUS) SEA SURFACE
TEMPERATURES AND IS IN AN AREA OF MODERATE (15-20 KNOT) VERTICAL
WIND SHEAR (VWS). TS 27W CURRENTLY HAS GOOD EQUATORWARD OUTFLOW,
HOWEVER, THE POLEWARD OUTFLOW IS BEING SUPPRESSED BY SUBSIDENCE
FROM A TUTT CELL LOCATED EAST OF GUAM. THE SYSTEM IS TRACKING TO
THE NORTHWEST ALONG THE SOUTHWESTERN PERIPHERY OF A BUILDING
SUBTROPICAL RIDGE (STR) LOCATED TO THE NORTHEAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE IN THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 27W WILL CONTINUE TO TRACK TO THE NORTHWEST FOR THE NEXT
72 HOURS ALONG THE SOUTHEASTERN PERIPHERY OF THE STR. THE SYSTEM IS
FORECAST TO GRADUALLY INTENSIFY AS MARGINALLY FAVORABLE CONDITIONS
WILL PERSIST. AROUND TAU 72, THE SYSTEM WILL APPROACH THE RIDGE
AXIS AND THE TRACK WILL SHIFT MORE NORTHERLY AS IT BEGINS TO
RECURVE. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGH TAU
48, LENDING HIGH CONFIDENCE IN THIS PORTION OF THE JTWC TRACK
FORECAST.
   C. AFTER TAU 72, TS 27W WILL PASS THE RIDGE AXIS AND ROUND THE
WESTERN EDGE OF THE STR AND ACCELERATE NORTHEASTWARD. THE SYSTEM
WILL ALSO BEGIN TO INTERACT WITH AN APPROACHING MID-LATITUDE
TROUGH. INCREASED POLEWARD OUTFLOW ASSOCIATED WITH THE MID-LATITUDE
TROUGH WILL ALLOW FOR ADDITIONAL INTENSIFICATION, EVENTUALLY
REACHING A MAXIMUM OF 80 KNOTS BY THE END OF THE FORECAST PERIOD.
NUMERIC MODEL GUIDANCE BEGINS TO SPREAD IN BOTH TRACK DIRECTION AND
SPEED AFTER TAU 48 WITH JGSM BEING THE PRINCIPLE OUTLIER, TRACKING
THE SYSTEM MUCH FARTHER EAST THAN THE REMAINING CONSENSUS MEMBERS.
THE SYSTEM SPEED ALSO VARIES LENDING A HIGH DEGREE OF UNCERTAINTY
IN THE SYSTEM SPEED IN THE LATER TAUS. DUE TO THE VARIABILITY IN
BOTH TRACK AND SPEED, THERE IS LOW CONFIDENCE IN THIS PORTION OF
THE JTWC TRACK FORECAST.//
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