WPAC: INVEST 91W

[euro6208]

91W INVEST 150106 1800 2.6N 157.3E WPAC 15 1003

JTWC 18Z update...Big blowup of convection...

[xtyphooncyclonex]

Past 3 to 4 GFS runs are showing a weak or moderate tropical storm than the typhoon which is substantially different from the typhoon before. I think of it being weaker...

[dexterlabio]

more often when the Euro shows a typhoon, that system really turns into something significant. Looks like Euro has a good handle on this system from the start...conditions aren't just favorable enough for a typhoon this time..

[cycloneye]

more often when the Euro shows a typhoon, that system really turns into something significant. Looks like Euro has a good handle on this system from the start...conditions aren't just favorable enough for a typhoon this time..

However even if this doesn't turn strong windwise,it will be a big problem with the plenty of rainfall right?

[cycloneye]

Upgraded to Medium.

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 3.0N 160.0E
IS NOW LOCATED NEAR 2.5N 157.6E, APPROXIMATELY 270 NM SOUTH OF
POHNPEI. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A SLOWLY
CONSOLIDATING, PARTIALLY-EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC)
WITH FORMATIVE BANDING. A 062317Z METOP-B 89 GHZ IMAGE INDICATES
DEEP CONVECTIVE BANDING OVER THE WESTERN SEMI-CIRCLE OF THE LLCC. A
062315Z ASCAT IMAGE REVEALS A BROAD BUT DEFINED CIRCULATION WITH 15
TO 20 KNOT WINDS. UPPER-LEVEL ANALYSIS DEPICTS A MARGINALLY-
FAVORABLE ENVIRONMENT WITH LOW TO MODERATE (10 TO 20 KNOTS) VERTICAL
WIND SHEAR OFFSET BY BROAD UPPER-LEVEL DIFFLUENCE, ENHANCED BY AN
UPPER-LEVEL TROUGH TO THE NORTHEAST. MAXIMUM SUSTAINED SURFACE WINDS
ARE ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA LEVEL PRESSURE IS
ESTIMATED TO BE NEAR 1002 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS UPGRADED TO
MEDIUM.

[euro6208]

NWS GUAM

MODELS ARE STILL DEBATING WHAT WILL BECOME OF THE CIRCULATION
SOUTH OF POHNPEI. GFS AND GFS ENSEMBLE STILL WANT TO DEVELOP THIS
FEATURE INTO A TROPICAL CYCLONE WHILE THE ECMWF DOES NOT. DESPITE
THE STRENGTH THE FEATURE WILL ATTAIN A CIRCULATION OF SOME KIND
WILL PASS CLOSE TO YAP SOMETIME MONDAY. IT WILL PASS SOUTH OF THE
MARIANAS AND SOUTH OF 10N ON SUNDAY. LOW-LEVEL CONVERGENCE NORTH
OF THE CIRCULATION WILL INCREASE CLOUDS AND THE CHANCES OF
SHOWERS SUNDAY THROUGH SUNDAY NIGHT. WHILE SCATTERED SHOWERS ARE
POSSIBLE LEFT IT OUT OF THE FORECAST FOR NOW BECAUSE CONFIDENCE
IS NOT TOO HIGH.

[dexterlabio]

However even if this doesn't turn strong windwise,it will be a big problem with the plenty of rainfall right?

Well, true...a disorganized cyclone making a last-minute blowup of convection just off the coast often means trouble.. especially if it's moving at a slow pace..

[xtyphooncyclonex]

Latest GFS shows 987 mb before crossing the country

[xtyphooncyclonex]

ECMWF or Euro showed Peipah to a strong typhoon but it was a sheared tropical storm...

But most of the time, Euro terribly underestimates storm intensities.

[dexterlabio]

Even GFS showed a January cyclone last year becoming a super typhoon but it only turned out to be a weak tropical storm... I don't want to start a model war here but my point is, it's hard to bet on a typhoon at this time of the year when the winter monsoon is active and cold dry air dominates half of SE Asia, even if a major computer model says so...so I'm inclined to go with the Euro solution, and perhaps the Parallel GFS...

[xtyphooncyclonex]

IMO I think this would be stronger than Lingling, though it's too early to tell. This is over the open WPAC waters and well away from major landmass. Conditions are more favorable than the same time last year.. Lingling was close to Mindanao..

JTWC upgraded this to medium faster than Lingling

[euro6208]

91W INVEST 150107 1200 3.0N 155.2E WPAC 20 1002

Not much change...

[cycloneye]

12z Parallel GFS is more stronger.

[cycloneye]

12z ECMWF a tad stronger.

[euro6208]

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 2.5N
157.2E, IS NOW LOCATED NEAR 4.4N 154.2E, APPROXIMATELY 232 NM
SOUTHEAST OF CHUUK. RECENT ANIMATED MULTISPECTRAL SATELLITE IMAGERY
AND A 072256Z METOP-B MICROWAVE IMAGE DEPICT WEAKENED AND
DISORGANIZED DEEP CONVECTION ASSOCIATED WITH AN ILL-DEFINED LOW-
LEVEL CIRCULATION CENTER (LLCC). UPPER-LEVEL ANALYSIS INDICATES A
MARGINALLY FAVORABLE ENVIRONMENT WITH LOW TO MODERATE (05 TO 15
KNOT) VERTICAL WIND SHEAR WITH LIMITED OUTFLOW. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 1002 MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS DOWNGRADED TO LOW.

[ohno]

Goner?

B. TROPICAL DISTURBANCE SUMMARY:
(1) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 4.4N
154.2E, HAS DISSIPATED AND IS NO LONGER SUSPECT FOR THE DEVELOPMENT
OF A SIGNIFICANT TROPICAL CYCLONE IN THE NEXT 24 HOURS.

[euro6208]

NWS GUAM

ASCAT ANALYSIS AND SATELLITE LOOPS INDICATE THE CIRCULATION CENTER
ASSOCIATED WITH INVEST AREA 91W IS NEAR 2N157.5E TODAY. JTWC HAS
DOWNGRADED 91W TO LOW POTENTIAL FOR DEVELOPMENT. INVEST 91W HAS NOT
MOVED MUCH AND SEEMS SLIGHTLY LESS ORGANIZED FROM YESTERDAY. A TWIN
CIRCULATION SOUTH OF THE EQUATOR AT 8S158E SEEMS MUCH MORE DOMINANT
ON A REGIONAL SCALE. MODEL SOLUTIONS ARE STILL VERY DIFFERENT. THE
CIRCULATION IS EXPECTED TO DEVELOP ONLY SLOWLY AND EVENTUALLY DRIFT
TOWARD WEST-NORTHWEST...AND IT WILL NEED TO BE WATCHED CLOSELY IN
THE COMING DAYS.

[euro6208]

Models showing only a TD or TS at most east of Visayas...CMC the most bullish bringing it to typhoon strength...

[euro6208]

91W INVEST 150108 1200 5.1N 153.0E WPAC 15 1010

[euro6208]

NWS GUAM

THE CIRCULATION SOUTH OF POHNPEI WILL MOVE NORTHWEST THE NEXT FEW
DAYS. MODELS DEBATE IF THE FEATURE WILL REMAIN A CIRCULATION OR
WEAKEN TO JUST A TROUGH FOR A WHILE. EITHER WAY...LOW-LEVEL
CONVERGENCE NORTH OF THE FEATURE WILL INCREASE CLOUDS AND THE
CHANCES OF SHOWERS MONDAY AND TUESDAY. WHILE SCATTERED SHOWERS ARE
POSSIBLE LEFT IT OUT OF THE FORECAST FOR NOW BECAUSE CONFIDENCE
IS NOT TOO HIGH AS MODELS KEEP THE BULK OF THE SHOWERS SOUTH OF
THE LOCAL AREA.

MODELS TODAY ARE PREDICTING THE CIRCULATION SOUTH OF POHNPEI WILL
REMAIN WEAK AS IT MOVES ACROSS THE WESTERN PACIFIC. THE LATEST
SCATTEROMETER AND SATELLITE DATA TEND TO AGREE WITH THE WEAKENING
TREND PORTRAYED IN THE MODELS.

THE WEAK CIRCULATION SOUTH OF POHNPEI NEAR 2N157E REMAINS POORLY
DEFINED AND NEARLY STATIONARY. MODELS...NAMELY THE GFS...HAVE
TAKEN A STEP BACK ON ITS DEVELOPMENT THE NEXT SEVERAL DAYS AND
NOW SHOW A SURFACE TROUGH HEADING WESTWARD TOWARD YAP BY EARLY
NEXT WEEK WITH A DIFFERENT CIRCULATION FORMING WITHIN THE TROUGH.
ECMWF MAINTAINS NEARLY THE SAME SCENARIO IT HAS SHOWN FOR NEARLY
THE PAST WEEK...A NEAR-EQUATORIAL TROUGH PERSISTING BETWEEN 3N
AND 6N AND INCREASING MOISTURE AT YAP AND PALAU LATE IN THE
WEEKEND AND EARLY NEXT WEEK. CURRENT FORECAST CONTINUES TO
ANTICIPATE AN UNFOLDING SCENARIO SIMILAR TO THAT SEEN IN THE
ECMWF.