ATL: RAFAEL - Post-Tropical - Discussion

[wxman57]

Here's a new surface plot. Still no well-defined LLC, though there is a broad area of low pressure across the eastern Caribbean. Best I can estimate is somewhere near 14.8N/62.5W. Appears to be moving NNW, keeping the heavier squalls just west of the Lesser Antilles for the most part:

[CrazyC83]

The islands should still treat this as a tropical storm as the conditions would be identical...

[wxman57]

The islands should still treat this as a tropical storm as the conditions would be identical...

Yes, it will produce some sustained winds of 30-40 mph with gusts of 50-60 mph regardless of whether it develops an LLC and becomes a TS. Lots of heavy rain, too.

[Fego]

Here's a new surface plot. Still no well-defined LLC, though there is a broad area of low pressure across the eastern Caribbean. Best I can estimate is somewhere near 14.8N/62.5W. Appears to be moving NNW, keeping the heavier squalls just west of the Lesser Antilles for the most part:

Do you think that this systema will develop a LLC before crossing PR or USVI?

[NDG]

I believe there is finally a LLC finally trying to get going near 14N & 61.8W, about 50 miles west of St Lucia.
Most of the convection east of the possible LLC.

[Gustywind]

12/1145 UTC 13.6N 61.4W T1.0/1.0 98L
12/0545 UTC 12.2N 60.5W T1.0/1.0 98L

[cycloneye]

80%.

BROAD AREA OF LOW PRESSURE LOCATED OVER THE EASTERN CARIBBEAN SEA
ABOUT 100 MILES WEST OF DOMINICA CONTINUES TO PRODUCE A LARGE
AREA OF SHOWERS AND THUNDERSTORMS WELL EAST AND SOUTHEAST OF THE
CENTER OVER PORTIONS OF THE LESSER ANTILLES. SURFACE OBSERVATIONS
INDICATE THAT THIS SYSTEM IS PRODUCING WINDS TO TROPICAL STORM
FORCE IN RAINBANDS...HOWEVER SATELLITE IMAGERY AND SURFACE
OBSERVATIONS STILL SUGGEST THAT THE LOW LACKS A CLOSED SURFACE
CIRCULATION. UPPER-LEVEL WINDS ARE EXPECTED TO BECOME MORE
CONDUCIVE FOR DEVELOPMENT...AND IT IS LIKELY THAT A TROPICAL
DEPRESSION OR TROPICAL STORM WILL FORM DURING THE NEXT DAY OR TWO.
IF THIS OCCURS...A TROPICAL STORM WARNING WOULD BE REQUIRED FOR
PORTIONS OF THE LEEWARD ISLANDS. THIS SYSTEM HAS A HIGH CHANCE...80
PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS
AS IT MOVES NORTHWESTWARD OR NORTH-NORTHWESTWARD AT 10 TO 15 MPH.
STRONG GUSTY WINDS AND LOCALLY HEAVY RAINFALL ARE POSSIBLE ACROSS
PORTIONS OF THE LESSER ANTILLES AND THE VIRGIN ISLANDS DURING THE
NEXT COUPLE OF DAYS. AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT
WILL BE INVESTIGATING THIS SYSTEM THIS AFTERNOON. FOR ADDITIONAL
INFORMATION ON THIS SYSTEM...PLEASE MONITOR PRODUCTS FROM YOUR
LOCAL WEATHER OFFICE AND HIGH SEAS FORECASTS ISSUED BY THE NATIONAL
WEATHER SERVICE.

[Driftin]

Are those hot towers i see near the center?

http://www.ssd.noaa.gov/goes/east/carb/rb-animated.gif

[wxman57]

Still can't find any evidence of anything but a broad, weak circulation. It appears to be centered around 15.2N/62.6W, near the red crosshairs on the image below. Winds across the Lesser Antilles generally 5-15 kts. Still 25 kts in Barbados.

[cycloneye]

Recon finds west wind.

183930 1421N 06234W 9772 00270 0075 +259 +216 271008 008 001 001 00

[wxman57]

Recon finds west wind.

183930 1421N 06234W 9772 00270 0075 +259 +216 271008 008 001 001 00

Yes, there are west winds. That was never the question as was indicated by many obs across the region. The issue is that it is a very large and broad circulation with relatively light winds, not a well-defined LLC. West winds do not qualify it as a TD/TS. It needs that well-defined circulation with convection near the center - something it still lacks.

Still looks like the heavy squalls will past east of PR, Luis. Maybe even east of the Virgin Islands.

[cycloneye]

The red circle is where Recon found the lowest pressure and windshift.

[cycloneye]

18z Best Track.

AL, 98, 2012101218, , BEST, 0, 147N, 627W, 30, 1006, LO

http://ftp.nhc.noaa.gov/atcf/tcweb/inve ... 012.invest

[Gustywind]

Increasing numbers for 98L! Looks close to TD status given these numbers, but let's wait and see. That will be interresting to have the latest from the NHC...


12/1745 UTC 14.3N 62.3W T2.0/2.0 98L
12/1145 UTC 13.6N 61.4W T1.0/1.0 98L

[wxman57]

Don't know why the plane is heading way down south now. Nothing down there. We can see evidence of 2-3 remnant eddies rotating around a larger area of low pressure. I think the NW-NNW wind 5-10 kts it's finding down there is an old eddy. The circulation is clearly not well-defined enough to be upgraded.

Here's a surface plot. Just 5-15 kt winds across the Lesser Antilles now. Center of the broad surface low near the red crosshairs.

[caribepr]

Don't know why the plane is heading way down south now. Nothing down there. We can see evidence of 2-3 remnant eddies rotating around a larger area of low pressure. I think the NW-NNW wind 5-10 kts it's finding down there is an old eddy. The circulation is clearly not well-defined enough to be upgraded.

Here's a surface plot. Just 5-15 kt winds across the Lesser Antilles now. Center of the broad surface low near the red crosshairs.

http://home.comcast.net/~cgh57/98Lf.gif

There are reports of 50 mph winds over Barbados. Something isn't jiving here?

[wxman57]

Don't know why the plane is heading way down south now. Nothing down there. We can see evidence of 2-3 remnant eddies rotating around a larger area of low pressure. I think the NW-NNW wind 5-10 kts it's finding down there is an old eddy. The circulation is clearly not well-defined enough to be upgraded.

Here's a surface plot. Just 5-15 kt winds across the Lesser Antilles now. Center of the broad surface low near the red crosshairs.

http://home.comcast.net/~cgh57/98Lf.gif

There are reports of 50 mph winds over Barbados. Something isn't jiving here?

Around 6 hours ago, Barbados briefly reported a sustained wind of 34 kts (39 mph), as indicated in their decoded obs below. At 17Z, there was a wind gust to 41 kts (47 mph) with sustained winds of 29 kts (33 mph). There are definitely a few small pockets of TS-strength winds in those squalls, but that's not uncommon in any tropical disturbance.

West of Barbados, the squalls across the Lesser Antilles either aren't as heavy as earlier or those very small pockets of heaviest squalls and TS winds are missing all the observing stations.


TBPB| |121800|77.0F|75.0F|94.2%|190|027|000|2147483647.00|999|OVC|Rain
TBPB| |121700|77.0F|77.0F|100.0%|200|029|041|2147483647.00|999|OVC|Rain
TBPB| |121600|77.0F|77.0F|100.0%|190|027|000|2147483647.00|999|OVC|Rain
TBPB| |121500|77.0F|77.0F|100.0%|200|026|000|2147483647.00|999|BKN|Rain
TBPB| |121400|77.0F|77.0F|100.0%|190|021|000|2147483647.00|999|BKN|Light Rain
TBPB| |121300|78.0F|77.0F|94.2%|160|034|000|2147483647.00|999|BKN|Light Rain
TBPB| |121200|80.0F|77.0F|88.9%|160|028|040|2147483647.00|999|BKN|Light Rain
TBPB| |121100|78.0F|78.0F|100.0%|150|025|040|2147483647.00|999|BKN|Light Rain
TBPB| |121000|78.0F|78.0F|100.0%|150|024|000|2147483647.00|999|BKN|Light Shower(s) Rain
TBPB| |120900|78.0F|77.0F|94.2%|180|025|000|2147483647.00|999|BKN|Light Shower(s) Rain
TBPB|SP|120809|78.0F|78.0F|100.0%|170|029|041|2147483647.00|999|BKN|Light Shower(s) Rain
TBPB| |120800|78.0F|77.0F|94.2%|170|031|000|2147483647.00|999|BKN|Light Shower(s) Rain
TBPB| |120700|80.0F|75.0F|83.7%|190|025|000|2147483647.00|999|BKN|In the vicinity Shower(s)

[HurricaneAndrew92]

I honestly believe in a TD at 5pm...

[cycloneye]

From Dr Jeff Masters:

Hurricane Hunters found about a 10-mile wide band of westerly winds near 13.5°N 63°W, but the circulation is pretty broad, and may not qualify as a TD yet. Also.no TS force winds at flight level yet.

[HurricaneAndrew92]

http://www.ssd.noaa.gov/PS/TROP/floater ... -long.html
Look at the clouds popping up in the SE