WPAC: INVEST 91W

[Typhoon10]

Another Invest crops up!

[HURAKAN]

AN AREA OF CONVECTION HAS PERSISTED NEAR 9.7N 112.4E,
APPROXIMATELY 335 NM EAST OF HO CHI MINH, VIETNAM. ANIMATED
MULTISPECTRAL SATELLITE IMAGERY INDICATES FLARING DEEP CONVECTION
OVER THE SOUTH CHINA SEA ALONG THE MONSOON TROUGH AXIS. UPPER LEVEL
ANALYSIS INDICATES THAT THIS AREA IS IN A HOSTILE ENVIRONMENT WITH
HIGH (>30 KNOTS) EASTERLY VERTICAL WIND SHEAR. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 10 TO 15 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 1007 MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS POOR.

a lot of shear

[cycloneye]

Typhoon10, I edited the post to put the image instead of the link that was very long.

[Typhoon10]

Typhoon10, I edited the post to put the image instead of the link that was very long.

Thanks for that, am still learning how to put the imagine into threads

[supercane]

Hard to tell from the still, but the loop clearly shows NE shear.

[supercane]

..but the CIMSS product makes the howling shear clear.

[KWT]

High shear but also a highly divergent sety-up, in many ways its a similar set-up to pre-Bonnie in the Atlantic.

[Chacor]

30 knots of shear is never good for a developing system.

Still, doesn't really look that bad for a storm under that much shear.

[Typhoon10]

Upgraded to fair by JWTC

(2) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 9.7N
112.4E, IS NOW LOCATED NEAR 10.9N 112.8E, APPROXIMATELY 360 NM EAST
OF HO CHI MINH CITY, VIETNAM. ANIMATED INFRARED SATELLITE IMAGERY
SHOWS PERSISTENT DEEP CONVECTION NEAR THE MONSOON TROUGH AXIS IN THE
SOUTH CHINA SEA. A 241411Z ASCAT PASS REVEALS THAT A PORTION OF THE
NARROW TROUGH HAS FORMED INTO A WEAK, YET SYMMETRIC LOW LEVEL
CIRCULATION CENTER (LLCC). A 241815Z AMSU MICROWAVE IMAGE DEPICTS
CURVED INFLOW AND WEAK BANDING WITH THE BULK OF THE DEEP CONVECTION
STILL TO THE SOUTHWEST OF THE LLCC, SIGNALING THE PRESENCE OF EAST-
NORTHEASTERLY VERTICAL WIND SHEAR (VWS). HOWEVER, THE VWS HAS
STARTED TO RELAX SOME OVER THE LAST 12 HOURS AND IS DOWN TO 15-25
KNOTS. UPPER-AIR SOUNDINGS FROM DA NANG AND HO CHI MINH CITY,
VIETNAM SHOW RELATIVELY WEAK EASTERLY WINDS (5-30 KNOTS) THROUGHOUT
THE COLUMN. ADDITIONALLY, AS THE SYSTEM IS FORMING AND STARTING TO
DRIFT WESTWARD, BOTH DIRECTIONAL AND SPEED SHEAR HAVE DECREASED.
FINALLY, UPPER-AIR ANALYSIS INDICATES THERE IS ALSO INCREASING
DIVERGENCE ALOFT. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT
12 TO 17 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR
1007 MB. DUE TO THE FORMATION OF A WEAK LLCC AND DECREASING VWS, THE
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS UPGRADED TO FAIR.

[Chacor]

JMA 00z:
LOW PRESSURE AREA 1004 HPA NEAR 12N 112E WNW SLOWLY.

[supercane]

From NRL KML file:

Tropical Cyclone 91W

25 Jul 2010 0000Z
Location: 11.7 111.4
Winds: 20 knots
Central Pressure: 1004 hPa

[supercane]

Formation prob increasing, but looks like it will run out of room before anything significant happens.

[Chacor]

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 10.9N
112.8E, IS NOW LOCATED NEAR 11.7N 111.4E, APPROXIMATELY 280 NM EAST-
NORTHEAST OF HO CHI MINH, VIETNAM. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY CONTINUES TO SHOW PERSISTENT DEEP CONVECTION ALONG THE
MONSOON TROUGH AXIS IN THE SOUTH CHINA SEA WITH WEAK LOW LEVEL
BANDING WRAPPING INTO THE SYSTEM. A 241411Z ASCAT PASS AND A
250245Z PARTIAL ASCAT PASS DEPICT A BROAD LOW LEVEL CIRCULATION WITH
10 TO 15 KNOT WINDS AT THE CENTER AND 25 KNOT WESTERLIES SOUTH OF
THE CIRCULATION. A 242348Z SSMIS MICROWAVE IMAGE SHOWS SLIGHT
CURVATURE BUT NO ORGANIZED CENTRAL CONVECTION. UPPER LEVEL ANALYSIS
INDICATES THE SYSTEM IS BENEATH AN AREA OF BROAD DIFFLUENCE WITH 20
TO 25 KNOTS OF NORTHEASTERLY VERTICAL WIND SHEAR. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 12 TO 17 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 1007 MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS REMAINS FAIR.

[supercane]

From NRL KML file with TRMM added


Tropical Cyclone 91W

25 Jul 2010 1200Z
Location: 12.3 111.4
Winds: 20 knots
Central Pressure: 1007 hPa

[supercane]

still looks like center is on NE edge of convection due to shear

[supercane]

WWJP25 RJTD 251200
WARNING AND SUMMARY 251200.
<snip>
LOW PRESSURE AREA 1004 HPA NEAR 12N 111E WNW SLOWLY.
<snip>

JMA agrees in position with JTWC but has lower pressure.

[HURAKAN]

25/1432 UTC 12.1N 111.2E T2.0/2.0 91W -- West Pacific

30 knots

[KWT]

Whilst still looking somewhat sheared it looks decent enough right now and 30kts IMO looks about right.

[supercane]

From NRL KML file:

Tropical Cyclone 91W

25 Jul 2010 1800Z
Location: 12.3 110.6
Winds: 20 knots
Central Pressure: 1007 hPa


ASCAT missed the system

[supercane]

SLP map from Digital Atmosphere 18Z