WPAC: INVEST 98W

[Extratropical94]

98W INVEST 150923 1800 15.0N 152.0E WPAC 15 NA

[1900hurricane]

15*N? That seems way too far north to me.



Anyway, 98W doesn't have too much model support, but I suppose it could briefly develop into something. It's not a bad looking invest and the 12Z ECMWF does show a little something developing from this for a day or two.

[euro6208]

NWS

Code: Select all

LATEST FORECAST ISSUANCE REQUIRED SEVERAL GRID ADJUSTMENTS.
INHERITED FORECAST BRINGS THE TROPICAL DISTURBANCE THROUGH THE
NORTHERN CNMI ON SATURDAY NIGHT. ONLY MODEL STILL SUPPORTING THIS
SOLUTION IN THE WIND FIELDS IS THE ECMWF. ALL THE OTHER MODELS
PASS THE DISTURBANCE TO THE SOUTH OF GUAM ON SATURDAY NIGHT.
SATELLITE TRENDS SUPPORT A TRACK FARTHER SOUTH...SO HAVE UPDATED
THE WIND GRIDS ACCORDINGLY FOR A TRACK SOUTH OF GUAM TODAY THROUGH
DAY 5 USING THE LATEST GFS RUN. NEXT FORECAST CONUNDRUM INVOLVES
SHORT TERM POPS. SMALL SIZE AND TRACK OF THE APPROACHING TROPICAL
DISTURBANCE SUGGESTS SCATTERED SHOWERS WILL ONLY AFFECT GUAM AND
ROTA WATERS TONIGHT. GFS TIME-HEIGHT CROSS SECTION AS WELL AS THE
LATEST WATER VAPOR IMAGERY INDICATE SUBSIDENCE AND MID-LEVEL
DRYING OVER SAIPAN AND TINIAN TONIGHT...SO WILL ADHERE TO A DRY
BIAS FOR THESE ZONES. OTHERWISE...STILL EXPECT DRIER TRADE-WIND
PATTERN TO TAKE OVER ON SUNDAY...THEN PREVAIL THROUGH DAY 7.

[1900hurricane]

Visible imagery shows some broad low level turning associated with 98W. It doesn't look like any development is imminent, but there's some good vorticity there for now.

[euro6208]

Only CMC develops this down the road. Becomes a typhoon as it makes landfall over central Japan.

[euro6208]

000
WWMY80 PGUM 250355
SPSMY

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TIYAN GU
200 PM CHST FRI SEP 25 2015

GUZ001>004-260000-
GUAM-ROTA-TINIAN-SAIPAN-
200 PM CHST FRI SEP 25 2015

A TROPICAL DISTURBANCE IS CENTERED 12N148E OR ABOUT 240 MILES EAST-
SOUTHEAST OF GUAM. THIS DISTURBANCE WILL CONTINUE TO MOVE SLOWLY
WEST-NORTHWEST TOWARD THE MARIANAS OVER THE NEXT DAY OR TWO. AS THIS
SYSTEM APPROACHES...EXPECT SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS TO DEVELOP OVER THE AREA LATE THIS AFTERNOON AND
CONTINUE THROUGH SATURDAY.

PERIODS OF LOCALLY HEAVY SHOWERS...DANGEROUS LIGHTNING AND WIND
GUSTS OF 25 TO 30 KNOTS ARE POSSIBLE DURING THE PASSAGE OF THIS
DISTURBANCE. RAINFALL AMOUNTS OF TWO TO FOUR INCHES ARE ALSO
POSSIBLE WHICH CAN CAUSE FLOODING IN POOR DRAINAGE AND LOW-LYING
AREAS. ROUGH SEAS AND LOW VISIBILITIES ARE ALSO EXPECTED DURING
THE PASSAGE OF THIS DISTURBANCE.

STAY INFORMED TO LATEST STATEMENTS AND FORECASTS ISSUED BY THE
NATIONAL WEATHER SERVICE. PRODUCTS ISSUED BY THE NATIONAL WEATHER
SERVICE ARE POSTED ON THE WFO GUAM WEB PAGE AT
http://WWW.PRH.NOAA.GOV/GUAM/ (ALL LOWER CASE).

$$

ZIOBRO

[euro6208]

First mention by JTWC.

AN AREA OF CONVECTION HAS PERSISTED NEAR 11.0N 148.4E,
APPROXIMATELY 258 NM EAST-SOUTHEAST OF GUAM. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY DEPICTS FLARING DEEP CONVECTION ASSOCIATED WITH A
DEVELOPING LOW-LEVEL CIRCULATION CENTER. A 242316Z ASCAT PASS SHOWS
A 15 TO 20 KNOT CIRCULATION WITH STRONGER (UP TO 35) KNOT WINDS OVER
THE NORTHWESTERN QUADRANT. UPPER-LEVEL ANALYSIS INDICATES THE
DISTURBANCE IS LOCATED IN A MARGINAL ENVIRONMENT WITH MODERATE VWS
AND GOOD DIFFLUENCE ALOFT. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 1008 MB. DUE TO THE ILL-DEFINED LLCC AND MARGINAL
ENVIRONMENT, THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT
TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS LOW.

[euro6208]

Interesting discussion from NWS...

SATELLITE IMAGERY THIS AFTERNOON SHOWS A CIRCULATION NEAR 12N148E
OR ABOUT 240 MILES SOUTHEAST OF GUAM. RADAR DATA SHOWED ECHO TOPS
NEAR 55KFT AND WINDS UP TO 55 KTS AT 17KFT TO THE EAST OF GUAM
THIS AFTERNOON. THIS AREA SHOULD MOVE TOWARDS THE LOCAL AREA AND
BRING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS TONIGHT AND
PART OF SATURDAY. GFS SHOWS THE CIRCULATION GOING SOUTH OF GUAM.
ECMWF DEPICTS THE DISTURBANCE PASSING JUST NORTH OF ROTA SATURDAY.
ECMWF APPEARS CLOSER TO WHAT SEEMS TO BE OCCURRING SO POPULATED
GRIDS IN THE NEAR TERM WITH THAT MODEL. BECAUSE THE CIRCULATION
WILL PASS JUST NORTH OF ROTA HAD TO SPLIT THE ZONES BECAUSE OF
WIND DIFFERENCE. TINIAN AND SAIPAN MAY GET LESS SHOWER ACTIVITY
BUT FELT IT TOO FINE A POINT SO BROAD-BRUSHED THE SHOWER COVERAGE
FOR ALL ZONES.

WHILE THE STRONG WINDS OBSERVED IN THE RADAR DATA PROBABLY WILL NOT
WORK ITS WAY DOWN TO THE SURFACE IT MAY BE INDICATIVE OF SOME
DEVELOPMENT IN THE CIRCULATION. THIS IS THE REASON THAT A SPECIAL
WEATHER STATEMENT WAS ISSUED FOR THE MARIANAS. MODELS KEEP THE
SYSTEM WEAK AND IT EVENTUALLY MAY BE ABSORBED INTO THE LARGE SCALE
FLOW ASSOCIATED WITH TYPHOON DUJUAN. AS IT PASSES ACROSS THE
MARIANAS PERIODS OF HEAVY RAIN MAY OCCUR AT TIMES TONIGHT AND
SATURDAY MORNING. A FEW WINDS GUST ABOVE 30 MPH MAY ALSO BE
OBSERVED...ESPECIALLY IN THE HEAVIER SHOWERS.

[euro6208]

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 11.0N
148.4E, IS NOW LOCATED NEAR 15.1N 146.1E, APPROXIMATELY 125 NM
NORTHEAST OF ANDERSEN AFB, GUAM. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY DEPICTS WEAK LOW-LEVEL CIRCULATION EMBEDDED WITHIN TROUGHING
AND LITTLE ASSOCIATED CONVECTION. A 260509Z ASCAT PASS DEPICTS
TROUGHING THROUGH THE AREA ENHANCED BY STRONG 15 TO 20 KNOT WESTERLY
FLOW. UPPER-LEVEL ANALYSIS INDICATES A POOR ENVIRONMENT WITH
CONVERGENCE ALOFT AND 10 TO 15 KNOT VERTICAL WIND SHEAR. GLOBAL
MODELS INITIALIZE WITH A WEAK CIRCULATION THAT DISSIPATES WITHIN 24
HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1008 MB.
DUE TO THE PRESENCE OF A LOW-LEVEL CIRCULATION WITH NO MODEL
DEVELOPMENT, THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT
TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS LOW.

[1900hurricane]

Starting to fall apart now. Getting too close to Dujuan's and just running to more unfavorable conditions in general.

[euro6208]

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 15.1N
146.1E, HAS DISSIPATED AND IS NO LONGER SUSPECT FOR THE DEVELOPMENT
OF A SIGNIFICANT TROPICAL CYCLONE IN THE NEXT 24 HOURS.