WPAC: GONI - Post-Tropical

[cycloneye]

Models develop this into a strong Typhoon.

97W INVEST 150810 1800 8.0N 161.0E WPAC 15

[1900hurricane]

I was wondering how much longer it was going to take before something on that monsoon trough got tagged as an invest. I haven't really looked at the specifics of the recent model runs, but just based off of recent history and the climatology of El Nino years, this thing likely has a bright future ahead of it.

[euro6208]

NWS

MODEL GUIDANCE HAS NOT CHANGED MUCH CONCERNING THE EASTERN
MICRONESIA DISTURBANCE. AT THIS EARLY STAGE OF DEVELOPMENT MODELS
STILL RANGE FROM SOME TYPE OF TROPICAL CYCLONE...EITHER A
DEPRESSION OR TROPICAL STORM...AFFECTING THE NORTHERN MARIANAS
SOMEWHERE BETWEEN THIS WEEKEND OR MIDDLE OF NEXT WEEK...OR JUST
PASSING BY WELL EAST OF THE MARIANAS. HOWEVER...THE LOCATION OF
THIS DISTURBANCE HAS BEEN A HOT SPOT FOR PRODUCING TROPICAL
CYCLONES THAT HAVE AFFECTED THE MARIANAS THIS YEAR. WE WILL
CONTINUE TO CLOSELY MONITOR THIS SYSTEM.

[euro6208]

Much better organized...

[euro6208]

Looks super ripe for intensification with Depth 26 over 100, SST's above 30C (31C to 32C at it's present location), and TCHP is sporadic but favorable...





It's located in a low-moderate shear environment and sandwiched between two walls of shear although shear near the Marianas is decreasing significantly...

[euro6208]

EURO 12Z run takes a monster 928 mb Cat 5 Goni right through the Northern Marianas while the latest 00Z seems to indicate a possible recurve before impact. It intensifies it very rapidly from 992 mb to 974 mb to 944 mb and peak of 917 mb...

[euro6208]

Now this will be an interesting few weeks...

18Z and 00Z GFS has twins, Goni and Atsani developing from the monsoon trough and both incredibly at astonishing intensity, Cat 5's, wreaking havoc over the Area. Takes Goni or Atsani through the Marianas while the other recurves out to sea east of the Marianas...

00Z GFS incredible, 898 mb Goni alongside 891 mb Atsani in the P.I sea...

[cycloneye]

12z Best Track.

97W INVEST 150811 1200 9.7N 159.0E WPAC 15 1010

[euro6208]

12Z EURO has a strengthening upper end TS passing north of Saipan and becoming a significant typhoon in 120 hours and bottoming out at 946 mb right smack into central Taiwan and China...Soudelor part 2...

12Z GFS much weaker, had it as a Cat 5 in all of the past 5 runs, now takes a 969 mb Goni a little bit north of Saipan but more south than EURO, than the last update. Peaks it at 916 mb and slams it into Taiwan...

[1900hurricane]

JTWC has 97W now at a low chance of development within 24 hours, up from no mention.

[Yellow Evan]

GFS might be overdoing this like it did with Chan-hom. The system is quite large, and if it stays that way like the GFS depicts it as, this could inherit dry air like Chan-hom did. But we'll see as if the system doesn't get quite so large, Category 5 intensity is still attainable.

[dexterlabio]

I lean more to Euro on this one. It is shown as a rather intense cyclone for several runs from the ECMWF so I think there is a shot at super or maybe even a Cat5.

[euro6208]

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 9.8N
159.6E, IS NOW LOCATED NEAR 9.8N 159.8E, APPROXIMATELY 70 NM WEST
OF UJELANG, MARSHALL ISLANDS. ANIMATED MSI SHOWS AN EXPANSIVE AREA
OF BROAD ELONGATED MID-LEVEL TURNING ASSOCIATED WITH LOW LEVEL
TROUGHING THAT IS BEING ENHANCED BY A STORNG WESTERLY WIND SURGE
ALONG THE EQUATOR. A 120407Z SSMI MICROWAVE IMAGE FURTHER DEPICTS
CONVECTION SOUTHWEST OF THE LLCC. ENVIRONMENTAL ANALYSIS SHOWS A
CONDUCIVE ENVIRONMENT WITH LOW VWS AND STRONG DIVERGENT OUTFLOW.
SSTS ARE ALSO FAVORABLE FOR DEVELOPMENT. GLOBAL MODELS ARE IN GOOD
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 1009 MB. THE
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS 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 98W and hits the Northern CNMI...




NAVGEM does a big shift south bringing Goni over Guam as a TS and brings a 979 mb system awfully close to Okinawa...



CMC 11 00z 10 12z had this getting absorbed by 98W and latest makes this the weakest of the two typhoons and recurves it. Peak 977mb...

[euro6208]

00Z EURO much weaker on this run takes a previously monster Atsani to just a weak area of low pressure passing over Guam in 72 hours...



Down to 979 mb east of the Philippines...



Down to 950 mb and recurves it possibly hitting Okinawa...

[euro6208]

06Z 964 mb...



Peak 919 mb

[euro6208]

Very lengthy discussion on the twins...

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.

[euro6208]

Strong shear between 550 and 300 mb is preventing the formation of thunderstorms until friday morning which should slow development but should increase more steadily as it nears the Marianas...