ATL: INVEST 98L - Discussion

[cycloneye]

Hi Gusty. It looks like high pressure gets strong and causes 98L to dive WSW. Something to watch here in the islands.

[Gustywind]

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SUN SEP 08 2013


TROPICAL WAVE IN THE CENTRAL ATLC IS ANALYZED FROM 21N37W TO A
1010 MB LOW NEAR 15N35W. THIS WAVE/LOW HAS BEEN NEARLY
STATIONARY OVER THE PAST 24 HOURS. LOW/WAVE IS EMBEDDED WITHIN A
SURGE OF DEEP MOISTURE AS DEPICTED ON TOTAL PRECIPITABLE WATER
IMAGERY. LOW REMAINS WELL DEFINED IN THE LOW AND MID LEVEL
SATELLITE WINDS. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE WITHIN 75 NM OF LINE FROM 15N30W TO 18N36W.

[Gustywind]

Hi Gusty. It looks like high pressure gets strong and causes 98L to dive WSW. Something to watch here in the islands.

Ok i was wondering that. Thanks Cycloneye . Let's stay on our guard.

[Gustywind]

SSD numbers...

08/0545 UTC 15.8N 35.5W T1.0/1.0 98L
07/2345 UTC 15.5N 34.9W T1.0/1.0 98L

[Gustywind]

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN SEP 08 2013

TROPICAL WAVE IN THE CENTRAL ATLC IS ANALYZED FROM 21N38W
THROUGH A 1010 MB LOW NEAR 16N36W TO 14N34W. THE WAVE/LOW HAS
BEEN NEARLY STATIONARY FOR THE PAST 24 HOURS. LOW/WAVE IS
EMBEDDED WITHIN A SURGE OF DEEP MOISTURE AS DEPICTED ON TOTAL
PRECIPITABLE WATER IMAGERY. WAVE REMAINS WELL DEFINED IN THE LOW
AND MID LEVEL SATELLITE WINDS. CLUSTERS OF SCATTERED MODERATE/
ISOLATED STRONG CONVECTION ARE WITHIN 60/75 NM OF LINE FROM
16N31W TO 18N38W.

[cycloneye]

12z Best Track.

AL, 98, 2013090812, , BEST, 0, 166N, 361W, 25, 1010, LO

[Gustywind]

08/1145 UTC 16.9N 36.2W TOO WEAK 98L
08/0545 UTC 15.8N 35.5W T1.0/1.0 98L

[gatorcane]

RAL update. System is on the move again:

At 1200 UTC, 08 September 2013, LOW INVEST (AL98) was located in the North Atlantic basin at 16.6°N and 36.1°W. The current intensity was 25 kt and the center was moving at 8 kt at a bearing of 320 degrees. The minimum central pressure was 1010 mb

To put things in perspective, it is the system on the far right-hand side of image. Looks like it is elongated but has some good convection and moisture:

[Gustywind]

2 PM TWD.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 35W/36W TO THE SOUTH OF
21N...MOVING WESTWARD 10 TO 15 KNOTS. A 1010 MB LOW PRESSURE
CENTER IS ALONG THE WAVE NEAR 16.5N. CONVECTIVE PRECIPITATION...
SCATTERED TO NUMEROUS STRONG FROM 18N TO 20N BETWEEN 36W AND
41W. WIDELY SCATTERED MODERATE TO ISOLATED STRONG FROM 15N TO
20N BETWEEN 28W AND 41W. THIS SYSTEM HAS A LOW CHANCE OF
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS...AND A LOW
CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 5 DAYS
WHILE IT MOVES TO THE WEST-NORTHWEST ABOUT 9 KNOTS.

[cycloneye]

BEGIN
NHC_ATCF
invest_DEACTIVATE_al982013.ren
FSTDA
R
U
040
010
0000
201309081823
NONE
NOTIFY=ATRP

[BigB0882]

You think this may come back in a few days? Is the environment forecast to get better as it moves West?

[gatorcane]

Latest IR Loop shows convection still firing despite the very unfavorable conditions:

[gatorcane]

Latest IR Loop shows convection still firing despite the very unfavorable conditions:

http://img268.imageshack.us/img268/6643/bdql.gif

[hurricaneCW]

It could be a sleeper type system or at the very least, it could enhance activity as it moves further west. Sometimes these systems sneak up on us. I still remember the TD 10/Katrina evolution.

[gatorcane]

You think this may come back in a few days? Is the environment forecast to get better as it moves West?

You never know. It looks like the wave will continue west for a while or even dip a little WSW and it could make it into the Caribbean. It's interesting the 18Z GFS now shows it developing in the Bahamas though it is very long-range so we need to see if this is a trend or not.

[Hammy]

if it keeps going the way its going right now, they may have to reactivate it a second time.

[gatorcane]

Yeah a bit surprised still this invest is not getting at least a mention by NHC at all. Been looking at the WV loop tonight (animated GIF below). The invest is the area in the center right-hand side of image with some purples/reds showing up. Upper-level dry air doesn't look that bad any longer (it did several days back) as we don't see as much orange shading around the area of this invest.

As far as shear, you can see a couple of ULLs causing shear. One to the NW of the system which has been inducing shear the past couple of days. That is moving NNW away from the invest. There is another one to the WSW that is moving WSW away from the system.

Also, it looks like finally some moist air is being brought up from the ITCZ to the SSW of the invest as can be seen by all the white clouds streaming north.

Convection may continue to pop off an on with this invest the next several days as the system moves W or WSW. Still should be watched IMHO in case it can find a window of opportunity further west:

[Gustywind]

Yeah a bit surprised still this invest is not getting at least a mention by NHC at all. Been looking at the WV loop tonight (animated GIF below). The invest is the area in the center right-hand side of image with some purples/reds showing up. Upper-level dry air doesn't look that bad any longer (it did several days back).

As far as shear, you can see a couple of ULLs causing shear. One to the NW of the system which has been inducing shear the past couple of days. That is moving NNW away from the invest. There is another one to the WSW that is moving WSW away from the system.

Also, it looks like finally some moist air is being brought up from the ITCZ to the SSW of the invest as can be seen by all the white clouds streaming north.

Convection may continue to pop off an on with this invest the next several days as the system moves W or WSW. Still should be watched IMHO in case it can find a window of opportunity further west:

Very interresting statement there Gatorcane Thanks for posting that.
Anyway, as Cycloneye said it this morning, us in the islands shoud keep an eye on that given the west and even wsw that may occur. Moreover, our Pro Mets of Meteo-France Guadeloupe continues to emphasize on the fact Thursday "weather conditions will deteriorate seriously, with rains and tstorms ".

[Gustywind]

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN SEP 08 2013


TROPICAL WAVE EXTENDS FROM 14N38W TO 21N38W MOVING W AT 10-15
KT. A 1010 MB LOW IS CENTERED ALONG THE WAVE AXIS NEAR 18N AND
THIS REMAINS THE FOCUS FOR WIDELY SCATTERED MODERATE CONVECTION
OCCURRING FROM 18N-23N BETWEEN 34W-42W. GLOBAL MODELS SUGGEST
THE WAVE WILL CONTINUE TO DRIFT WESTWARD DURING THE NEXT FEW
DAYS WEAKENING SOMEWHAT AS IT APPROACHES W OF 45W AS A MID-
LATITUDE UPPER LEVEL TROUGH DIGS SOUTHWARD AND BEGINS TO PROVIDE
AN INCREASED SHEAR ENVIRONMENT ACROSS THE CENTRAL TROPICAL ATLC.

[supercane]

000
AXNT20 KNHC 090547
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON SEP 08 2013

<snip>

...TROPICAL WAVES...

TROPICAL WAVE IN THE CENTRAL ATLC IS ANALYZED FROM 21N38W
THROUGH A 1012 MB LOW NEAR 17N38W TO 13N38W. THE WAVE/LOW HAS
MOVED NW 5-10 KT FOR THE PAST 24 HOURS. THE WAVE N OF THE LOW IS
EMBEDDED WITHIN A SURGE OF DEEP MOISTURE THAT IS BEING DRAWN NW
AWAY FROM THE WAVE AS DEPICTED ON TOTAL PRECIPITABLE WATER
IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN
30/45 NM OF LINE FROM 17N39W TO 20N42W.

<snip>
Source: http://www.nhc.noaa.gov/text/refresh/MIATWDAT+shtml/090547_MIATWDAT.shtml?