TYPHOON NIDA STATIONARY FOR THE PAST 48HRS, 97W INVEST SLOWLY INTENSIFYING

TROPICAL CYCLONE ADVISORY
NOV 30 2009

WIND IMAGERY

THERMAL IR IMAGERY

STEERING WIND/PRESSURE

RAINFALL IMAGERY ANALYSIS

WESTERN PACIFIC IR IMAGERY

TYPHOON NIDA (26W)

TYPHOON (CATEGORY 3) STAGE
CURRENT INTENSITY: MAX: 100kt GUST: 125kt (185-232kph)
CURRENT PRESSURE: 948MB
SURFACE WIND ANALYSIS: 100KT (185KPH) MSLP: 946.3MB
ADVANCE DVORAK TECHNIQUES (ADT): 99.6KT(184KPH) MSLP: 944.9B
CENTRAL REGION TEMP: -12.5C (EYE)
CENTRAL CLOUD TEMP: -61.0C (+15MM/HR)
FORECAST 12HRS: 90KT/167KPH

DISCUSSION:

TYPHOON (TY) 26W (NIDA), LOCATED APPROXIMATELY 330 NM SOUTH-SOUTHWEST OF IWO TO, HAS REMAINED QUASI-STATIONARY (QS) OVER THEPAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTSWEAKENING CONVECTION OVER ALL QUADRANTS WITH A RAGGED 50NM EYE. TY 26W HAS, IN FACT, REMAINED QS OVER THE PAST 36 HOURS AND IS LIKELY WEAKENING DUE TO A COMBINATION OF DRY AIR ENTRAINMENT (DAE) AND COLD WATER UPWELLING. THE TOTAL PRECIPITABLE WATER (TPW) PRODUCTS INDICATE DRY AIR ADVECTION JUST WEST OF THE SYSTEM WITH A WEDGE OF DRY AIR (25-40MM) WRAPPING INTO THE NORTHEAST QUADRANT. A 292032Z SSMI/S IMAGE DEPICTS EYEWALL EROSION TO THE SOUTH AS DRY AIR IS BEING PULLED INTO THE CORE, AND A ROUND 50NM DIAMETER EYE. ANIMATED WATER VAPOR IMAGERY CONTINUES TO SHOW GOOD RADIAL OUTFLOW WITH ENHANCED POLEWARD OUTFLOW INTO THE MIDLATITUDE WESTERLIES. THERE IS FAIR CONFIDENCE IN THE CURRENT POSITION AND MOTION DUE TO THE ERRATIC SLOW TRACK AND LARGE EYE, HOWEVER, 37 GHZ MICROWAVE IMAGERY SUPPORTS BOTH. THE CURRENT INTENSITY OF 100 KNOTS IS BASED ON THE HIGHER DVORAK ESTIMATES RANGING FROM 77 TO 102 KNOTS. THE 29/12Z 500 MB ANALYSIS DEPICTS A WEAK MID-LEVEL STEERING ENVIRONMENT WITH TY 26W POSITIONED BETWEEN THE SUBTROPICAL RIDGE (STR) TO THE EAST AND WEST WITH STRONG MIDLATITUDE (ZONAL) WESTERLIES NORTH OF 25N. THE UPPER-LEVEL FLOW REMAINS HIGH ZONAL ACROSS ASIA WITH NO SIGNIFICANT MID-LEVEL SHORT-WAVE TROUGHS EVIDENT IN THE UPSTREAM FLOW (IN IMAGERY AS WELL). THE 30/00Z SURFACE ANALYSIS DEPICTS STRONG LOW-LEVEL RIDGING ENTRENCHED NORTH AND WEST OF TY 26W.

A. NO CHANGES TO FORECAST PHILOSOPHY.

B. NUMERICAL GUIDANCE REMAINS IN POOR AGREEMENT WITH TWODISTINCT CLUSTERS; NOGAPS, GFDN, AND WBAR STILL FAVOR A RECURVATURESCENARIO AND TRACK THE SYSTEM NORTH-NORTHEASTWARD TO NORTHEASTWARDRAPIDLY, WHILE JGSM, TC-LAPS, UKMO, ECMWF, AND GFS FAVOR A SLOWERWESTWARD TRACK WITH DISSIPATION. THE OFFICIAL FORECAST FAVORS THESLOW WESTWARD MOVEMENT WITH DISSIPATION AFTER TAU 72. AS THE SYSTEMWEAKENS, STEERING IS EXPECTED TO SHIFT TO THE LOW-LEVELS AND TY 26WIS LIKELY TO TRACK WESTWARD TO SOUTHWESTWARD UNDER THE NORTHEASTERLYFLOW. THE DISSIPATION SCENARIO IS BASED ON INCREASING VERTICAL WINDSHEAR DUE TO A COMBINATION OF LOW-LEVEL NORTHEASTERLY FLOW, ASSOCIATED WITH THE RIDGE BUILDING NORTH OF THE SYSTEM, AND ZONAL UPPER-LEVEL WESTERLY FLOW AS WELL AS DAE AND COOL WATER UPWELLING.

C. IN THE EXTENDED TAUS, TY 26W WILL CONTINUE TO WEAKEN AND SHOULD TURN SOUTHWESTWARD AND ACCELERATE WITHIN THE LOW-LEVEL FLOW. THERE IS STILL UNCERTAINTY WITH THE TIMING OF THE DISSIPATION AND THE TURN SOUTHWESTWARD. ADDITIONALLY, SEVERAL MODELS INDICATE THAT THE REMNANTS WILL TRACK CYCLONICALLY AND GET ABSORBED INTO A DEVELOPING STORM NEAR OR NORTHWEST OF GUAM.

TROPICAL DISTURBANCE 97W INVEST
SEVERE ALERT (12-24HRS FORMATION) STAGE
CURRENT INTENSITY: MAX: 15kt GUST: 20kt (28-37kph)
CURRENT PRESSURE: 1006MB
SURFACE WIND ANALYSIS: 28KT (52KPH) MSLP: 1005.8MB
ADVANCE DVORAK TECHNIQUES (ADT): 0KT(0KPH) MSLP: 0MB
CENTRAL REGION TEMP: -0C (N/A)
CENTRAL CLOUD TEMP: -0C (+50MM/HR)
FORECAST 12HRS: 0KT/0KPH

DISCUSSION:

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 2.2N 160.0E, IS NOW LOCATED NEAR 5.6N 153.7E, APPROXIMATELY 150 NM SOUTHEAST OF CHUUK. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS A BROAD REGION OF TROUGHING WITH SPORADIC CONVECTION IN THE VICINITY OF THE TROUGHING. CURRENTLY THERE DOES NOT APPEAR TO BE A SINGULAR CIRCULATION DEVELOPING, WITH MULTIPLE REGIONS OF TURNING IDENTIFIED IN THE IMAGERY. A 292329Z ASCAT IMAGE SUPPORTS THE TROUGH EXTENDING FROM CHUUK TO THE SOUTH OF POHNPEI. THE DEEPEST CONVECTION REMAINS TO THE NORTHWEST OF THE TROUGHING. UPPER LEVEL ANALYSIS DEPICTS A POINT SOURCE ANTICYCLONE IS LOCATED TO THE EAST OF THE TROUGHING WITH A REGION OF DIFFLUENCE ASSOCIATED WITH THE ANTICYCLONE EXTENDING OVER THE LOW LEVEL TROUGH, WHICH IS PROVIDING GOOD UPPER LEVEL OUTFLOW SUPPORT. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 10 TO 15 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1005 MB. BASED ON THE POOR ORGANIZATION OF THE LOW LEVEL ENVIRONMENT AND SPORADIC CONVECTION, THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS POOR

JUST VOTE OR COMMENT FOR FEEDBACK

STORM KROVANH SLOWLY INTENSIFYING, 02C LIKELY TO ENTER WESTERN PACIFIC

IMAGERY OF TROPICAL STORM 12W KROVANH (STRONG)

STRUCTURE OF KROVANH

CLOSE UP NEAR THE CENTER OF KROVANH

TROPICAL STORM 12W/KROVANH (STRONG)

8-29-09

3P

LOCATION: 26.99N, 146.99E (OPEN PACIFIC)
MSLP: 986.0MB
WINDSPEED: 50-65KT (93-120KPH [DVORAK: MSLP: 984.0MB VMAX: 55KT/102KPH])
MOVEMENT: NNW 15KT/28KPH
RAINRATE: 21MM/HR
EYE TEMP: +2C AT 13KM HIGH 150KM RADIUS (DVORAK: -69.31C)
NEXT 12HRS: 60KT/111KPH

DISCUSSION:

TROPICAL STORM (TS) 12W (KROVANH) HAS GRADUALLY INTENSIFIED AND TRACKED NORTH-NORTHWESTWARD ALONG THE SOUTHWESTERN PERIPHERY OF A MID-LEVEL SUBTROPICAL RIDGE TO THE NORTHEAST. ENVIRONMENTAL CONDITIONS HAVE BEEN FAVORABLE FOR DEVELOPMENT. ANIMATED WATER VAPOR SATELLITE IMAGERY SHOWS EXCELLENT RADIAL OUTFLOW OVER THE SYSTEM WITH A TROPICAL UPPER TROPOSPHERIC (TUTT) CELL TO THE WEST PROVIDING POLEWARD VENTILA- TION AND AN UPPER LEVEL RIDGE TO THE SOUTH ENHANCING EQUATORWARD OUTFLOW. ITS PROXIMITY TO RIDGE AXES HAS ALSO ACCOUNTED FOR THE LOW VERTICAL WIND SHEAR ALOFT. ADDITIONALLY, ALONG-TRACK TEMPERATURES ARE WELL IN EXCESS OF 28 DEGRESS CELSIUS. CURRENT POSITION AND INTENSITY ARE BASED ON ANIMATED MULTISPECTRAL IMAGERY AND ON DVORAK FIXES FROM PGTW, RJTD, AND KNES WITH A FAIR DEGREE OF CONFIDENCE
THE INTENSITY FORECAST HAS NOT CHANGED BUT THE TRACK FORECAST HAS CHANGED SLIGHTLY SINCE THE PREVIOUS BULLETIN. THIS TRACK IS RIGHT OF THE PREVIOUS FORECAST AND RECURVES THE SYSTEM SOONER WITHOUT MAKING LANDFALL INTO CENTRAL JAPAN.

TROPICAL STORM KROVANH IS EXPECTED TO CONTINUE TRACKING NORTHWESTWARD ALONG THE PERIPHERY OF THE STEERING RIDGE DESCRIBED IN PARA 2.A AND STEADILY INTENSIFY, PEAKING AT 65 KNOTS AT TAU 36. BY TAU 48, IT WILL BEGIN TO RECURVE TO THE NORTHEAST AS A MID-LEVEL TROUGH CURRENTLY OVER SOUTHERN MONGOLIA, DESCENDS INTO JAPAN AND CAUSES A BREAK/WEAKNESS IN THE STEERING RIDGE. BY TAU 72, TS 12W WILL COMMENCE ITS EXTRA-TROPICAL TRANSITION

AFTER TAU 72, TS 12W WILL ACCELERATE NORTHEASTWARD AND BECOME FULLY EXTRA-TROPICAL BY TAU 96. THE AVAILABLE NUMERIC GUIDANCE IS IN BETTER AGREEMENT ON THIS CYCLE. WITH THE EXCEPTION OF EGRR AND JGSM ON THE LEFT SIDE OF THE ENVELOPE, THE REMAINDER OF THE MODEL TRACKERS ARE IN TIGHT PACKING WITH CONSENSUS AND ECMWF ON THE LEFT EDGE OF THE PACKING. THIS TRACK FORECAST IS SLIGHTLY LEFT OF CONSENSUS.


JUST VOTE OR COMMENT FOR FEEDBACK

12W DEVELOPED OFF WESTERN PACIFIC, DEEPENING RAPIDLY

IMAGERY OF TROPICAL DEPRESSION 12W

STRUCTURE OF 12W

NEAR THE CENTER

8-28-09 1P

LOCATION: 22.60N, 148.02E (OPEN PACIFIC)
MSLP: 1000.0MB
WINDSPEED: 30-40KT (56-74KPH [DVORAK: MSLP: 998.8MB VMAX: 32KT/59KPH])
MOVEMENT: STATIONARY
RAINRATE: 21MM/HR
EYE TEMP: +1C AT 13.5KM HIGH 170KM RADIUS (DVORAK: -62.35C)
NEXT 12HRS: 40KT/74KPH

DISCUSSION:

TROPICAL DEPRESSION (TD) 12W, LOCATED APPROXIMATELY 425 NM EAST-SOUTHEAST OF IWO TO HAS TRACKEDNORTH-NORTHWESTWARD AT 08 KNOTS OVER THE PAST SIX HOURS. RECENT ANIMATED MULTISPECTRAL IMAGERY SHOWS A LOW LEVEL CIRCULATION CENTER (LLCC) HAS BEEN CONTINUING TO DEVELOP UNDER A REGION OF DEEP CONVECTION. THE CONVECTION HAS DECREASED SLIGHTLY OVER THE PAST 06 HOURS BUT SHOWS BETTER ORGANIZATION AS BANDING HAS STARTED TO DEVELOP INTO THE LLCC. UPPER LEVEL ANALYSIS DEPICTS A FAVORABLE ENVIRONMENT FOR FURTHER DEVELOPMENT, WITH MULTIPLE OUTFLOW CHANNELS OVER THE SYSTEM. A TROPICAL UPPER TROPOSPHERIC TROUGH CELL HAS DEVELOPED AROUND 26.1N 146.3E AND HAS HELPED TO ENHANCE THE POLEWARD OUTFLOW CHANNEL. A TROUGH NEAR 22.7N 163.0E HAS CONTINUED TO ALLOW GOOD OUTFLOW TO THE EAST. SOUTH OF THE LLCC UPPER LEVEL EASTERLY FLOW HAS CONTINUED TO MAINTAIN AN EQUATORWARD OUTFLOW CHANNEL. WITH LOW VERTICAL WIND SHEAR (VWS) AND FAVORABLE SEA SURFACE TEMPERATURES (SST) FURTHER DEVELOPMENT OF THIS SYSTEM IS EXPECTED TO CONTINUE IN THE NEAR TERM.

CURRENTLY TD 12W IS FORECAST TO TRACK ALONG THE SOUTHWESTERN QUADRANT OF A MID-LEVEL SUBTROPICAL RIDGE (STR).AS A ID-LATITUDE TROUGH LOCATED OVER THE SEA OF JAPAN LIFTS NORTHWARD,THE STR IS EXPECTED TO BUILD WESTWARD OVER JAPAN CAUSING A MORE WESTWARD SHIFT IN THE TRACK THROUGH TAU 72. INTENSITY IS EXPECTED TO INCREASE ASSOCIATED WITH THE MULTIPLE OUTFLOW CHANNELS THROUGH TAU 24, HOWEVER THE UPPER LEVEL OUTFLOW IS NOT EXPECTED TO REMAIN AS VIGOROUS AS CURRENTLY OBSERVED, LEADING TO A SLOWER INTENISIFICATION BEYOND TAU 24. SST AND VWS WILL REMAIN FAVORABLE THROUGHOUT THE FORECAST PERIOD. CONFIDENCE IN THE FORECAST IS LOW BASED ON POOR MODEL INITIALIZATION LEADING TO LIMITED GUIDANCE.

BEYOND TAU 72 THERE IS GREAT UNCERTAINTY REGARDING THE FORECAST TRACK AND INTENSITY. MODEL GUIDANCE CURRENTLY SHOWS THE SYSTEM TRACKING TO THE SOUTH OF JAPAN BY TAU 120 AS THE STR CONTINUES BUILDING OVER SOUTHERN JAPAN. INTENSITY GUIDANCE INDICATES THAT WEAK DEVELOPMENT IS EXPECTED TO CONTINUE, BUT THE FORECAST HAS A SLIGHT DECREASE AT TAU 120 ASSOCIATED WITH ITS CLOSE PASSAGE TO SOUTHERN JAPAN.

JUST VOTE OR COMMENT FOR FEEDBACK

TYPHOON VAMCO WEAKENING

IMAGERY OF TYPHOON VAMCO

TYPHOON VAMCO STRUCTURE

EYE OF TYPHOON VAMCO


8-24-09 1P

LOCATION: 31.80N, 154.82E (OPEN PACIFIC)
MSLP: 966MB
WINDSPEED: 80-95KT (148-176KPH [DVORAK: MSLP: 927.5MB VMAX:112.4KT/208KPH])
MOVEMENT: N 10KT/19KPH
RAINRATE: 21MM/HR
EYE TEMP: +3C 13.0KM HIGH 75KM RADIUS (DVORAK: +5.6C)
NEXT 12HRS: 75-85KT/139-157KPH

DISCUSSION:

TYPHOON (TY) 11W (VAMCO), LOCATED APPROXIMATELY 955 NM NORTHWEST OF WAKE ISLAND, HAS TRACKED NORTHWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL IMAGERY INDICATES THAT OVER THE PAST 12 HOURS, 11W HAS STARTED A NORTHWARD TRACK. DEEP CONVECTION REMAINS PERSISTENT NEAR THE RAGGED EYE, WITH A SLIGHT ELONGATION IN THE CIRCULATION FROM THE WEST-NORTHWEST TO EAST-SOUTHEAST. ANIMATED WATER VAPOR IMAGERY SHOWS THE WESTERN OUTFLOW INTO THE TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) CELL HAS BEEN BROKEN BY A BUILDING UPPER LEVEL RIDGE TO THE SOUTHWEST OF 11W. THE EASTERN OUTFLOW BEING SUPPORTED BY ANOTHER TUTT CELL TO THE SOUTHEAST HAS STARTED TO DIMINISH AS THE SEPARATION OF 11W AND THE TUTT CELL INCREASES. OVERALL, VAMCO REMAINS BUFFERED FROM SIGNIFICANT WEAKENING OVER THE PAST 12 HOURS DUE TO ITS COMPACT SIZE AND THE LACK OF DRY AIR ENTRAINMENT. ANIMATED TOTAL PRECIPITABLE WATER IMAGERY INDICATES DRY AIR CONTINUES TO WRAP AROUND THE PERIMETER OF 11W, BUT HAS YET TO PENETRATE INTO THE LOW LEVEL CIRCULATION CENTER. SEA SURFACE TEMPERATURES (SST) HAS BEEN DECREASING OVER THE PAST 12 HOURS AND ARE APPROACHING 28 C.

TY 11W WILL BEGIN TO TRACK NORTH-NORTHEASTWARD AS A MID-LATITUDE TROUGH CONTINUED TO DIG TO THE SOUTHEAST, AND THE SUB-TROPICAL RIDGE STEERING TY 11W RE-ORIENTS WITH THE APPROACHING TROUGH. 11W WILL MOVE INTO THE MID-LATITUDE WESTERLIES ASSOCIATED WITH THE TROUGH CAUSING AN INCREASE IN TRACK SPEED AND VERTICAL WIND SHEAR. TY 11W WILL START EXTRA-TROPICAL TRANSITION (ET) BY TAU 24 WITH ET COMPLETION BY TAU 36. DECREASING SST VALUES, INCREASING VERTICAL WIND SHEAR, AND DRY AIR ENTRAINMENT WILL QUICKLY BEGIN TO WEAKEN TY 11W AFTER TAU 24. ALTHOUGH THE SYSTEM IS EXPECTED TO COMPLETE ET BY TAU 36, THE REMNANT LOW WILL MAINTAIN STORM FORCE INTENSITY AS IT RAPIDLY TRACKS NORTHEASTWARD. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT WITH THE FORECAST TRACK AND ASSOCIATED INTENSITY.

JUST VOTE OR COMMENT FOR FEEDBACK

TYPHOON VAMCO SLOWLY WEAKENING AS IT MOVES NORTHWARD

IMAGERY OF TYPHOON VAMCO

TYPHOON VAMCO STRUCTURE (CLICK TO ENLARGE)

EYE OF TYPHOON VAMCO (CLICK TO ENLARGE)

8-22-09 3P

TYPHOON VAMCO/11W (CATEGORY 2)

LOCATION: 24.69N, 156.35E (OPEN PACIFIC)
MSLP: 938.1MB
WINDSPEED: 95-120KT (176-222KPH [DVORAK: 105KT/194KPH])
MOVEMENT: N 14KT/26KPH
RAINRATE: 12MM/HR
EYE TEMP: +3C 13.2KM HIGH 100KM RADIUS
NEXT 12HRS: 95-105KT/176-103KPH

DISCUSSION:

8-22-09 3P

TYPHOON VAMCO/11W (CATEGORY 2)

LOCATION: 24.69N, 156.35E (OPEN PACIFIC)
MSLP: 938.1MB
WINDSPEED: 95-120KT (176-222KPH [DVORAK: 105KT/194KPH])
MOVEMENT: N 14KT/26KPH
RAINRATE: 12MM/HR
EYE TEMP: +3C 13.2KM HIGH 100KM RADIUS
NEXT 12HRS: 95-105KT/176-103KPH


DISCUSSION:

TYPHOON (TY) 11W (VAMCO), LOCATED APPROXIMATELY 570 NM WEST-NORTHWEST OF WAKE ISLAND, HAS TRACKED NORTHWARD AT 07 KNOTS OVER THE
PAST SIX HOURS UNDER THE INFLUENCE OF A WESTWARD BUILDING SUB-TROPICAL RIDGE. ANIMATED MULTISPECTRAL IMAGERY DEPICTS AN ELONGATION
IN THE CENTRAL CONVECTION AROUND AN EYE FEATURE WHICH HAS BECOME PARTIALLY CLOUD FILLED AND IS ALSO SHOWING SIGNS OF EAST-WEST ELONG-
ATION. INTENSITY ESTIMATES HAVE DECREASED OVER THE PAST 12 HOURS, WITH A DVORAK ESTIMATE OF 5.0 FROM PGTW AND 5.5 FROM KNES, INDICATING
APPROXIMATELY 95 KNOTS. UPPER LEVEL OUTFLOW HAS PERSISTED IN THE POLEWARD CHANNEL HELPING TO MAINTAIN THE CURRENT INTENSITY, HOWEVER
AN UPPER LEVEL TROUGH TO THE NORTH OF TY 11W HAS STARTED TO IMPINGE ON THE NORTHWARD FLOW IN THE PAST 06 HOURS, SHIFTING A MAJORITY OF
THE OUTFLOW TO THE EASTERN PERIPHERY OF VAMCO.

THROUGH TAU 36, VAMCO WILL CONTINUE TO TRACK STEADILY NORTHWARD ALONG THE WESTERN PERIPHERY OF THE SUBTROPICAL STEERING RIDGE
MENTIONED IN PARA 2.A. IN THE SHORT TERM, VAMCO WILL SLOWLY WEAKEN OVER THE ENTIRE FORECAST PERIOD AS THE UPPER LEVEL OUTFLOW BECOMES
DISRUPTED BY AN APPROACHING MID-LATITUDE TROUGH. A BRIEF PERIOD OF INCREASED CONVECTION IS POSSIBLE AS THE MID-LATITUDE TROUGH ENHANCES
THE POLEWARD OUTFLOW PRIOR TO INCREASED VERTICAL WIND SHEAR AS THE TROUGH MOVES OVER VAMCO. EASTWARD OUTFLOW WILL HELP TO PREVENT QUICK
WEAKENING OF THE SYSTEM THROUGH TAU 36, HOWEVER, BEYOND TAU 36, THE ENVIRONMENT WILL QUICKLY BECOME UNFAVORABLE FOR TROPICAL DEVELOPMENT.
OCEAN HEAT CONTENT AND SEA SURFACE TEMPERATURES WILL CONTINUE TO DECREASE AS VAMCO TRACKS NORTHWARD. BETWEEN TAU 48 AND 72 INTERACTION
WITH THE MID-LATITUDE TROUGH WILL BEGIN THE EXTRA-TROPICAL TRANSITION PROCESS WITH COMPLETE TRANSITION EXPECTED BETWEEN TAU 72 AND 96. THE
TRACK WILL SHIFT TO THE NORTHEAST AS THE SUBTROPICAL RIDGE WEAKENS ALLOWING VAMCO TO MOVE NORTH OF THE RIDGE AXIS INTO THE MID-LATITUDE
WESTERLIES AND CAUSE IT TO INCREASE SIGNIFICANTLY IN TRACK SPEED. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT WITH THE FORECAST TRACK
AND ASSOCIATED INTENSITY.



COVERED (AUG 21-22 00:00UTC) 1 DAY
41.00 mm BAGUIO/LUZON ISLAND 16.42 120.60
43.00 mm MALAYBALAY/MINDANAO 8.15 125.08
47.00 mm MALABANG/MINDANAO 7.62 124.07
49.00 mm PAGADIAN/MINDANAO 7.83 123.47

COVERED (AUG 19-22 00:00UTC) 3 DAYS
103.00 mm BAGUIO/LUZON ISLAND 16.42 120.60

COVERED (AUG 15-22 00:00UTC) 7 DAYS
no 200mm and above rainfall

JUST VOTE OR COMMENT FOR FEEDBACK

TYPHOON VAMCO INTENSIFIED INTO CATEGORY 3 NEARING AT CATEGORY 4

TYPHOON VAMCO/11W (CATEGORY 3)

LOCATION: 18.94N, 157.19E (OPEN PACIFIC)
MSLP: 934.2MB
WINDSPEED: 105-135KT (194-250KPH [DVORAK: 110KT/204KPH])
MOVEMENT: N SLOWLY
RAINRATE: 12MM/HR
EYE TEMP: +2C 13.5KM HIGH 110KM RADIUS

NEXT 12HRS: 105-115KT/194-213KPH MAXIMUM WINDSPEED
NEXT 24HRS: POSSIBLE 120KT/222KPH MAXIMUM WINDSPEED

DISCUSSION:

TYPHOON (TY) 11W (VAMCO), LOCATED APPROXIMATELY 970 NM
EAST-SOUTHEAST OF IWO TO, HAS TRACKED NORTH-NORTHWESTWARD AT 02 KNOTS
OVER THE PAST SIX HOURS. THE STEERING ENVIRONMENT REMAINS WEAK AS THE
MID-LEVEL SUBTROPICAL RIDGE (STR) LOCATED TO THE EAST-NORTHEAST OF TY
11W HAS BEEN INTERRUPTED BY AN UPPER LEVEL TROPICAL TROPOSPHERIC
TROUGH (TUTT) CELL THAT HAS DEVELOPED FROM THE UPPER LEVEL INTO THE
MID-LEVEL. UPPER LEVEL ANALYSIS INDICATES THE POLEWARD OUTFLOW FROM
TY 11W INTO ANOTHER TUTT CELL LOCATED TO THE NORTH REMAINS WELL
DEFINED AND IN ASSOCIATION WITH THE EQUATORWARD OUTFLOW CHANNEL HAS
HELPED TO INCREASE THE MAXIMUM INTENSITY OVER THE PAST 06 HOURS. THE
VERTICAL WIND SHEAR (VWS) HAS REMAINED LOW OVER THE PAST 12 HOURS AND
THE SEA SURFACE TEMPERATURES (SST) HAVE HELPED TO FUEL THE RECENT
INCREASE IN INTENSITY. THE CURRENT POSITION AND INTENSITY ARE BASED
ON ANIMATED MULTISPECTRAL SATELLITE IMAGERY, AND ON DVORAK ESTIMATES
FROM PGTW, KNES, AND RJTD

TY 11W IS EXPECTED TO REMAIN IN A WEAK STEERING ENVIRONMENT
THROUGH THE NEXT 48 HOURS AS THE TUTT CELL TO THE EAST-NORTHEAST
BEGINS TO MOVE NORTHWARD TOWARDS THE MID-LATITUDE FLOW AND GET
ABSORBED. THIS WILL ALLOW THE MID-LEVEL STR TO BUILD WESTWARD
INCREASING TRACK SPEED FOR TY 11W BEYOND TAU 48. AN APPROACHING MID-
LATITUDE TROUGH WILL TRACK NORTH OF THE STR AXIS, CREATING A WEAKNESS
AROUND TAU 72 ALLOWING A TURN NORTHWARD. THE VWS AND SST WILL REMAIN
FAVORABLE FOR CONTINUED DEVELOPMENT THROUGH TAU 72. THE UPPER LEVEL
ENVIRONMENT WILL MAINTAIN IN A DUAL OUTFLOW PATTERN THROUGH THE EARLY
PORTION OF THE FORECAST HELPING TO ENHANCE AND SUSTAIN THE INTENSITY
OF TY 11W THROUGH TAU 72

AN APPROACHING MID-LATITUDE TROUGH IS FORECAST TO TRACK
ALONG THE NORTHERN AXIS OF THE STR, CREATING A WEAKNESS IN THE STR
AROUND TAU 72 ALLOWING FOR A MORE NORTHWARD TRACK. AS THE TROUGH
DIGS SOUTHWARD INCREASED UPPER LEVEL OUTFLOW WILL BE CAPTURED IN THE
MID-LATITUDE FLOW, HELPING TO SLOW THE WEAKENING OF TY 11W THROUGH
TAU 120. ADDITIONALLY, THE DIGGING TROUGH WILL ENHANCE TO BREAK IN
THE STR ALLOWING TY 11W TO RECURVE ALONG THE NORTHWESTERN PERIPHERY
OF THE STR. INCREASED VWS, DECREASED SST VALUES, AND LESS FAVORABLE
OCEAN HEAT CONTENT WILL BE THE PRIMARY FACTORS CAUSING THE SYSTEM
TO BEGIN WEAKENING BEYOND TAU 96. MODEL GUIDANCE IS IN GOOD ARGREE-
MENT WITH THE FORECAST REASONING. -BY NOAA

JUST VOTE OR COMMENT FOR FEEDBACK