WDPN33 PGTW 300300
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 22W (NALGAE) WARNING NR 12//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
    A. TYPHOON (TY) 22W (NALGAE), LOCATED APPROXIMATELY 500 NM EAST-
NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 13 KNOTS 
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY 
INDICATES THAT ALTHOUGH THERE HAS BEEN NO RECENT CHANGE, TY 22W 
REMAINS A VIGOROUS AND SYMMETRICAL SYSTEM WITH DEEP CONVECTIVE 
BANDING WRAPPING INTO THE LOW LEVEL CIRCULATION CENTER. 
A 292051Z SSMIS IMAGE REVEALS THE SYSTEM HAS LOST ITS MICROWAVE EYE, 
BUT HAS SHOWN AN INCREASE IN LOW LEVEL BANDING, PARTICULARLY OVER 
THE POLEWARD SEMICIRCLE. DVORAK ESTIMATES FROM ALL THREE AGENCIES 
HAVE STEADIED OUT AT 75 KNOTS. ANIMATED WATER VAPOR IMAGERY 
CONTINUES TO SHOW MILD IMPINGEMENT OVER THE NORTHWESTERN QUADRANT, 
BUT ENHANCED OUTFLOW TO THE EAST OF THE SYSTEM AND RADIAL OUTFLOW 
ELSEWHERE. TY 22W IS A WEST RUNNER, STEERED BY A STRONG AND DEEP 
SUBTROPICAL RIDGE CENTERED ALONG THE 25TH LATITUDE. THE LAST TWO 
FIXES HAVE SHOWN A STEADY SPEED OF ADVANCE OF 13 KNOTS. ALONG-TRACK 
VERTICAL WIND SHEAR VALUES ARE WELL BELOW 15 KNOTS AND SEA SURFACE 
TEMPERATURES ARE APPROXIMATELY 29 DEGREES. 
3.  A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY.
    B. TY 22W WILL RUN DEAD WEST ALONG THE SOUTHERN PERIPHERY OF THE 
SUBTROPICAL RIDGE. 500 MB PROGS INDICATE THAT A MID- TO UPPER LEVEL 
ANTICYCLONE NORTHEAST OF TAIWAN IS BUILDING EASTWARD AND PROVIDING A 
STEADY STEERING MECHANISM. TY 22W WILL INTENSIFY STEADILY UNTIL IT 
MAKES LANDFALL OVER NORTHEASTERN LUZON NEAR TAU 60. LOW VERTICAL 
WIND SHEAR AND FAVORABLE SEA SURFACE TEMPERATURES ARE EXPECTED TO 
REMAIN ALMOST UNCHANGED THROUGH TAU 72. THE PRIMARY WEAKENING 
MECHANISM FOR TY 22W WILL BE LAND INTERACTION WITH NORTHERN LUZON. 
THE FORECASTED INTENSITY TREND IS LIMITED TO A CLIMATOLOGICAL RATE 
BASED ON THE BEHAVIORS OF TY 20W AS IT TRACKED THROUGH THE 
PHILIPPINE SEA, AS WELL AS TO THE CURRENT OUTFLOW PATTERN. RECENT 
GUIDANCE IS NOW POINTING TOWARDS A TRACK COMPLETELY ACROSS LUZON 
RATHER THAN THROUGH THE STRAIT, WHICH WILL MAKE FOR A 12 HOUR OVER-
LAND PERIOD AND A 40 PERCENT REDUCTION IN INTENSITY. FAVORABLE 
CONDITIONS OVER THE SOUTH CHINA SEA WILL ALLOW TY 22W TO RAMP UP 
SLIGHTLY, BUT NOT TO THE INTENSITY IT WILL ATTAIN OVER THE 
PHILIPPINE SEA. MODEL GUIDANCE CONTINUES TO COME INTO BETTER 
AGREEMENT WITH EACH SUCCESSIVE MODEL RUN AND IS NOW IN EXCELLENT 
AGREEMENT THROUGH TAU 72. THE JTWC FORECAST IS FASTER THAN CONSENSUS 
AND BETWEEN CONSENSUS AND ECMWF AND JGSM. CONSENSUS IS BEING SLOWED 
AND PULLED POLEWARD BY THE BAROTROPIC MODEL. 
   C. THE EXTENDED RANGE TRACK OF TY 22W WILL FOLLOW THAT OF TY 20W. 
AS THE SUBTROPICAL RIDGE CONTINUES TO BUILD EASTWARD, A COL IN THE 
SUBTROPICAL RIDGE BETWEEN THE OCEANIC ANTICYCLONE AND THE 
ANTICYCLONE EXTENDING OUT OF ASIA MINOR WILL CREATE A WEAKNESS THAT 
WILL ALLOW THE STORM TO BEND POLEWARD TOWARD THE GULF OF TONKIN. LOW 
VERTICAL WIND SHEAR AND WARM SEA SURFACE TEMPERATURES WILL SUSTAIN 
AN ENVIRONMENT THAT WILL MAKE FOR A SLOW DE-INTENSIFICATION TREND, 
ALSO SIMILAR TO TY 20W. LONG RANGE TRACK GUIDANCE IS STILL SPLIT, 
BUT MODELS ARE INCREASINGLY COMING TO SHOW THE POLEWARD BEND AFTER 
TAU 72. 
NNNN