WPAC: ATSANI - Post-Tropical

[cycloneye]

98W INVEST 150812 0000 9.9N 169.7E WPAC 15 1010

[1900hurricane]

Yup, here's the eastern portion of the monsoon trough I mentioned back in the WPac thread. This one also likely has a bright future. WPac gonna WPac.

[euro6208]

Likely will be Atsani...

AN AREA OF CONVECTION HAS PERSISTED NEAR 10.8N 170.7E,
APPROXIMATELY 85 NM NORTH-NORTHEAST OF WOTJE, MARSHALL ISLANDS.
ANIMATED MSI SHOWS A BROAD ELONGATED TURNING ASSOCIATED WITH LOW
LEVEL TROUGHING THAT IS BEING ENHANCED BY A WESTERLY WIND BURST.
ENVIRONMENTAL ANALYSIS DEPICTS A CONDUCIVE ENVIRONMENT WITH LOW VWS
AND STRONG DIVERGENT OUTFLOW AS WELL AS HIGH SSTS. GLOBAL MODELS
ARE IN DECENT AGREEMENT WITH DEVELOPMENT OF THIS DISTURBANCE BEYOND
72 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 10 TO 15
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1010 MB.
THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS UPGRADED TO LOW.

[euro6208]

000
WWPQ80 PGUM 120046
SPSPQ

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TIYAN GU
1000 AM CHST WED AUG 12 2015

PMZ172-173-174-181-130000-
CHUUK-POHNPEI-KOSRAE-MAJURO-
1000 AM CHST WED AUG 12 2015

...DISTURBED WEATHER OVER EASTERN MICRONESIA...

SATELLITE IMAGES SHOW SHOWERS AND THUNDERSTORMS IN A LARGE AREA OVER
CHUUK...POHNPEI...KOSRAE AND MAJURO. A TROUGH STRETCHES EASTWARD
ALONG 10N-11N FROM SOUTH OF GUAM TO JUST NORTH OF MAJURO...PASSING
THROUGH CIRCULATIONS CENTERED NEAR POHNPEI NEAR 9N159E AND NORTH OF
MAJURO NEAR 9N171E.

COMPUTER MODELS INDICATE SLOW DEVELOPMENT OF THE CIRCULATION NEAR
POHNPEI AS IT HEADS TOWARD THE NORTHWEST. THE CIRCULATION NEAR
MAJURO COULD ALSO DEVELOP IN THE COMING DAYS AS IT LIFTS TOWARD THE
NORTH-NORTHWEST.

LOCALLY HEAVY SHOWERS WILL PERSIST THROUGH THURSDAY FROM CHUUK TO
MAJURO. MAJURO SAW MORE THAN 6 INCHES OF RAIN IN A 12 HOUR PERIOD
OVERNIGHT. ADDITIONAL RAINFALL AMOUNTS OF 3 TO 6 INCHES ARE EXPECTED
AT MOST LOCATIONS.

SOUTHWEST TO WEST MONSOON WINDS WILL CONTINUE ACROSS THE AREA
GUSTING UP TO 30 KT IN HEAVIER SHOWERS THROUGH THURSDAY. SEA
CONDITIONS HAVE BECOME HAZARDOUS TO SMALL CRAFT FROM POHNPEI AND
KOSRAE TO THE MARSHALL ISLANDS. HIGH SURF ADVISORIES ARE ALSO IN
EFFECT FOR SOUTH AND WEST FACING REEFS OF THESE LOCATIONS.

RESIDENTS OF THE MARSHALL ISLANDS AND KOSRAE...POHNPEI AND CHUUK
STATES SHOULD MONITOR THIS SITUATION. LISTEN FOR LATER STATEMENTS...
AND INSTRUCTIONS FROM LOCAL EMERGENCY MANAGEMENT OFFICES.

$$

M. AYDLETT/W. AYDLETT

[euro6208]

[euro6208]

JMA kinda merges this with 97W and hits the Northern CNMI...




NAVGEM with Goni at peak east of the Marianas with a likely recurve...



CMC 11 00z 10 12z had this eating up 97W but 11 12z and 12 00z now keeping both systems separate and intensifies this more rapidly and more intense and recurves both out to sea. Peak 949 mb...

[euro6208]

EURO in 72 hours as Goni east of the Marianas...



Down to 944 mb hitting the Northern Marianas...



Down to 912 mb

[euro6208]

06Z peak of 881 mb and recurves...

[euro6208]

Even lower in this 12Z GFS...878 mb!

[euro6208]

LITTLE CHANGE MADE TO FORECAST. A MONSOON TROUGH CONTINUES TO
STRETCH ACROSS THE WESTERN PACIFIC FROM 11N130E TO THE DATELINE
AND 8N. A FEW CIRCULATIONS COULD BE FOUND ON THE TROUGH WITH ONE
NORTH OF OF POHNPEI AND ANOTHER NEAR MAJURO. THE POHNPEI
CIRCULATION APPEARS TO BECOMING THE DOMINANT FEATURE ALONG THE
MONSOON TROUGH.

THE BIG CONCERN FOR THE MARIANAS AND THE FORECAST CONTINUES TO BE
THE POHNPEI AND MAJURO CIRCULATIONS. GFS AND ECMWF STILL DEPICT
TWIN CIRCULATIONS ON THE MONSOON TROUGH. THE NAVGEM INITIALLY ONLY
HAS ONE CIRCULATION BUT DEVELOPS A SECOND ONE BY FRIDAY NIGHT NEAR
MAJURO. THE THREE MODELS KEEP THESE CIRCULATIONS DISTINCT THROUGH
THE FORECAST STILL PUSHING THE CIRCULATIONS TOWARDS THE NORTHWEST
OVER THE NEXT FEW DAYS.

YESTERDAY GFS HAD THE POHNPEI CIRCULATION PASSING NORTH OF SAIPAN
ON MONDAY...NOW IT SHOWS IT ON TUESDAY. YESTERDAYS NAVGEM HAD THE
POHNPEI CIRCULATION PASSING NORTH OF PAGAN ON MONDAY WHILE THE
CURRENT 12Z RUN HAS IT PASSING THERE ON SUNDAY NIGHT. ECMWF IS THE
MODEL WITH THE MOST CHANGE. THE 12Z RUN FROM TUESDAY PREDICTED THE
POHNPEI CIRCULATION PASSING OVER SAIPAN. THE 00Z RUN FROM YESTERDAY
SHOWED THE CIRCULATION PASSING SOUTH OF GUAM FRIDAY NIGHT. THE
LATEST 12Z RUN OF THE ECMWF NOW SHOWS THE CIRCULATION PASSING NEAR
ANATAHAN ON SATURDAY NIGHT. IT IS POSSIBLE THAT THE ECMWF IS COMING
INTO BETTER AGREEMENT WITH THE OTHER MODELS...BUT WITH ITS BIG
CHANGES OVER THE LAST FEW RUNS CAN THIS BE ITS FINAL CHANGE?

WITH THE MODELS IN FLUX...KEPT FORECAST AS IS FOR NOW. STILL FEEL
THAT THE POHNPEI CIRCULATION WILL PASS ACROSS THE NORTHERN CNMI
NORTH OF SAIPAN DURING THE FIRST HALF OF THE COMING WEEK. AS THE
CIRCULATIONS MOVE NORTHWARDS THEY WILL DRAG THE MONSOON TROUGH
ALONG WITH IT. SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THE
POHNPEI CIRCULATION AND THE MONSOON TROUGH WILL PUSH TOWARDS THE
MARIANAS. ISOLATED THUNDERSTORMS ARE EXPECTED TODAY AND TONIGHT AS
THE TROUGH AND CIRCULATION APPROACHES. SATELLITE AND RADAR IMAGERY
SHOW A LARGE AREA OF SHOWERS UNCOMFORTABLY CLOSE TO THE LOCAL
AREA. THIS HAS TO BE WATCHED AS SCATTERED SHOWERS MAY COVER THE
AREA FASTER THAN ORIGINALLY PREDICTED. AT THIS TIME STILL EXPECT
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ASSOCIATED WITH THE
CIRCULATION AND MONSOON TROUGH TO COVER THE MARIANAS FRIDAY
THROUGH AT LEAST SUNDAY NIGHT. GFS DOES SHOW SOME GAPS IN THE
RAINFALL COVERAGE SO SHOWERS COULD BECOME SPOTTY ON SUNDAY.

RAIN IS STILL EXPECTED TO TAPER OFF BY MONDAY. MODELS SHOW THAT
THE SECOND CIRCULATION...THE ONE CURRENTLY NEAR MAJURO ...WILL
PRODUCE A LARGE MONSOON TAIL. THIS TAIL WILL BRING SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS BACK TO THE MARIANAS THE SECOND
HALF OF THE COMING WEEK.

[Yellow Evan]

18z GFS a bit too north for my liking. But if it stays small, south, and moves slower than 97W, I don't see why this doesn't become a potent typhoon.

[euro6208]

Yeah 18Z is weaker only peaking this at 909 mb and still recurving it. Looks like both systems are fighting for supremacy lol...

[euro6208]

As of yesterday, Majuro saw 4 inches of rain in a 6-hr period overnight, bringing the 24-hr rain total up to 10.01 inches!

[euro6208]

Showers spreading over Kwajalein and Namu Atoll...LLC just northeast of the Island...

[euro6208]

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 10.8N 170.7E,
IS NOW LOCATED NEAR 10.4N 169.5E, APPROXIMATELY 149 NM NORTHEAST OF
KWAJALEIN, FSM. ANIMATED MSI SHOWS A BROAD ELONGATED CIRCULATION
EMBEDDED IN THE MONSOON TROUGH. UPPER LEVEL ANALYSIS INDICATES A
FAVORABLE ENVIRONMENT WITH LOW VWS AND GOOD RADIAL OUTFLOW. GLOBAL
MODELS PREDICT SIGNIFICANT DEVELOPMENT OF THIS SYTEM AFTER 48 HOURS.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 10 TO 15 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1010 MB. THE
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN
THE NEXT 24 HOURS REMAINS LOW.

[euro6208]

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 10.4N
169.5E, IS NOW LOCATED NEAR 12.1N 166.9E, APPROXIMATELY 211 NM
NORTH-NORTHWEST OF KWAJALEIN. ANIMATED MSI DEPICTS DISORGANIZED
CONVECTION ASSOCIATED WITH AN ILL-DEFINED LLCC. A 130351Z SSMI
MICROWAVE IMAGE REVEALS SHALLOW AND WEAK CONVECTIVE BANDING BROADLY
WRAPPING INTO THE CENTER. UPPER-LEVEL ANALYSIS INDICATES A
FAVORABLE ENVIRONMENT WITH LOW VWS AND GOOD POLEWARD OUTFLOW.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1006 MB. DUE TO
THE BROAD NATURE OF THE DISTURBANCE, THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS REMAINS LOW.

[euro6208]

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 12.1N
166.9E, IS NOW LOCATED NEAR 13.2N 164.2E, APPROXIMATELY 335 NM
NORTHWEST OF KWAJALEIN. RECENT ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY DEPICTS FORMATIVE BANDS OVER THE NORTHERN AND
SOUTHERN SEMI-CIRCLE WRAPPING INTO AN ILL-DEFINED LLCC. A 131010Z
METOP-B MICROWAVE IMAGE REVALS FRAGMENTED CONVECTIVE BANDING
BROADLY WRAPPING INTO THE CENTER. UPPER-LEVEL ANALYSIS INDICATES A
FAVORABLE ENVIRONMENT WITH LOW VWS AND GOOD DUAL OUTFLOW. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS. MINIMUM
SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1006 MB. DUE TO IMPROVED
ORGANIZATION, THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT
TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS UPGRADED TO MEDIUM.

[euro6208]

TXPQ26 KNES 131506
TCSWNP

A. TROPICAL DISTURBANCE (98W)

B. 13/1432Z

C. 13.8N

D. 163.6E

E. FIVE/MTSAT

F. T1.0/1.0/D1.0/24HRS

G. IR/EIR/SWIR

H. REMARKS...GREATER THAN 2/10 BANDING FOR DT=1.0. MET AND PT AGREE.
FT IS BASED ON DT.

I. ADDL POSITIONS

NIL


...SALEMI

[euro6208]

98W INVEST 150813 1800 14.0N 163.0E WPAC 20 1007

[1900hurricane]

Tropical Cyclone Formation Alert is up for 98W.