Atlantic INVEST 94L

[Nimbus]

Last night there was a wind shift from 235 degrees to 005 degrees that corresponded with the 6 millibar drop. Probably just an evening thunderstorm.

Shear over the northern half of the gulf the next few days would prevent a tropical storm from developing. Although there does seem to be a little rotation in the low clouds there has not been any persistent convection. IMHO the NHC would need to see some persistent convection along with a circulation on quikscat before declaring a TD.

[robbielyn]

twc says this is something to keep an eye on as shear is set to decrease over the next 24-48 hours. But I wonder where this is headed.

[Sjones]

I don't think there is any "for sure" track just yet as everything is switching around at the time.

[tailgater]

The area north Cuba @ 23N 77.5 W is catching my eye this morning and has a decent chance of becoming Chantal or at least a TD. Of course I have just looked at IR loops so far.

[NDG]

The area north Cuba @ 23N 77.5 W is catching my eye this morning and has a decent chance of becoming Chantal or at least a TD. Of course I have just looked at IR loops so far.

Is away from the surface trough in an area of much higher surface pressures, so I really doubt something will come out of it.

[tailgater]

Does someone have the Cuban radar site that is working? Thanks in advance.

[NDG]

Does someone have the Cuban radar site that is working? Thanks in advance.

I need to call my buddies over there to see what's up , for some reason the site is not updating its radar.

[tailgater]

Does someone have the Cuban radar site that is working? Thanks in advance.

I need to call my buddies over there to see what's up , for some reason the site is not updating its radar.

While your at it, get us a couple stoogies(sp)?

[caneman]

NHC still seems concerned. From the 8:00 TWd. Need to still be watched


Atlantic Tropical Weather Discussion
--------------------------------------------------------------------------------


000
AXNT20 KNHC 161036
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT JUN 16 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE
AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION
IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...
WEATHER OBSERVATIONS...AND RADAR.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...TROPICAL WAVES...

ATLC TROPICAL WAVE IS ALONG 36W/37W S OF 16N MOVING W 15-20 KT.
WAVE IS BETTER DEFINED THIS MORNING WITH A BROAD INVERTED-V
SIGNATURE. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM
1N-10N BETWEEN 34W-40W.

EASTERN MOST CARIBBEAN TROPICAL WAVE REMAINS OVER THE ABC
ISLANDS ALONG 69W/70W S OF 14N MOVING W 10-15 KT. WAVE REMAINS
EMBEDDED WITHIN DRY AIR SO NO SATELLITE SIGNATURE IS
DISCERNIBLE. ANY ASSOCIATED SHOWER ACTIVITY.

WESTERN MOST CARIBBEAN TROPICAL WAVE IS ALONG 78W/79W S OF 13N
MOVING W NEAR 10 KT. THIS WAVE IS MOVING INTO AN AREA OF UPPER
LEVEL MOISTURE THUS MASKING ANY SATELLITE SIGNATURE. ANY SHOWER
ACTIVITY IS IN THE E PACIFIC REGION.

...THE ITCZ...

ITCZ AXIS IS CENTERED ALONG 10N12W 5N26W 7N41W 5N54W. CLUSTERS
OF SCATTERED MODERATE/STRONG CONVECTION ARE WITHIN 150 NM OF THE
ITCZ AXIS FROM 40W-56W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS WITHIN 120 NM OF THE ITCZ AXIS FROM 22W-29W.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER RIDGE EXTENDS FROM AN UPPER HIGH OVER THE BAY OF
CAMPECHE TO LOUISIANA/MISSISSIPPI COVERING THE GULF W OF 85W
LEAVING MUCH OF THE GULF DRY THIS MORNING WITH ONLY ISOLATED
SHOWERS OVER THE NW GULF. THE BIGGEST CONCERN REMAINS THE BROAD
AREA OF LOW PRESSURE IN THE W CARIBBEAN AND A SURFACE TROUGH
THAT EXTENDS THROUGH THE YUCATAN CHANNEL TO OVER CENTRAL
FLORIDA. NO TROPICAL DEVELOPMENT IS EXPECTED OVER THE NEXT 24
HOURS...BUT HEAVY SHOWERS/THUNDERSTORMS ARE OCCURRING FROM OVER
CUBA TO OVER S FLORIDA AND THE FLORIDA KEYS. THIS SHOWERS WILL
CONTINUE TO MOVE NE TODAY.

CARIBBEAN SEA...
THE BIGGEST CONCERN REMAINS OVER THE W CARIBBEAN WHERE A BROAD
AREA OF LOW PRESSURE WITH AN ASSOCIATED SURFACE TROUGH THAT
EXTENDS FROM THE GULF OF HONDURAS THROUGH THE YUCATAN CHANNEL
INTO THE GULF OF MEXICO. NO TROPICAL DEVELOPMENT IS EXPECTED
OVER THE NEXT 24 HOURS...BUT HEAVY SHOWERS/THUNDERSTORMS
CONTINUE TO N OF 18N FROM 75W-85W WITH SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS S OF 20N W OF 80W TO OVER CENTRAL
AMERICA. IN THE UPPER LEVELS...AN UPPER SHORTWAVE TROUGH IS OVER
THE YUCATAN CHANNEL WITH AN UPPER RIDGE EXTENDING FROM
HONDURAS/NICARAGUA NE ACROSS CUBA/HISPANIOLA. THE E CARIBBEAN IS
DOMINATED BY AN UPPER TROUGH THAT EXTENDS FROM THE E ATLC
THROUGH THE CENTRAL ATLC TO 74W. THIS AREA IS FREE OF
SIGNIFICANT MOISTURE WITH THE EXCEPTION OF THE WIDELY ISOLATED
SHOWERS OVER THE LESSER ANTILLES BROUGHT IN BY THE MODERATE/
STRONG EASTERLY TRADE WINDS WITH THE STRONGEST WINDS ARE OVER
THE S/CENTRAL CARIBBEAN.

[DESTRUCTION5]

I think we have low pressure forming just east of FL as advertised by most global's..You can see the discernable spin east of Martin County.

http://radar.weather.gov/radar.php?prod ... B&loop=yes

[wxman57]

What I see out there this morning is what's left of the upper low kicking out to the NE across the Bahamas, taking most of the convection with it. There's a tropial wave moving westward into Nicaragura/Honduras along 85W. That's what's responsible for the small patch of storms east of Nicaragua. Once the tropical wave passes, I don't see anything else behind it to spark any convection across the NW Caribbean. So with the upper low gone and nothing to focus convection, all that's left would be seasonably normal low pressures in the SW-W Caribbean. A TC can't develop out of thin air, it needs some kind of disturbance to concentrate convection in one spot and generate convergence. That won't happen in the NW Caribbean without a disturbance. It's still an area to watch, because Chantal will very likely form there eventually. Could be in a week, could be another month or more.

[hial2]

Keep an eye in the area between Pinar del Rio,Cuba and Yucatan..It's losing the shear from the east bound ULL,now by the southern Bahamas..

[wxman57]

I think we have low pressure forming just east of FL as advertised by most global's..You can see the discernable spin east of Martin County.

http://radar.weather.gov/radar.php?prod ... B&loop=yes

Just remember that you're looking way above the surface with radar. You're seeing the upper low if you see any spin. I took a look and don't really see anything other than forming/dying showers that may give the illusion of spin.

Here's a link to a radar beam height calculator. At 100nm, for example the beam is looking about 13,000 feet above the surface:

http://www.wdtb.noaa.gov/tools/misc/bea ... width.html

[JonathanBelles]

Where is what this morning? Im still seeing a hint of spin east of the yucatan and Adll of you are saying watch the bahamas. Did something change overnight?

[TheRingo]

some convection east of the peninsula. Is that just thunderstorms?

[DESTRUCTION5]

I think we have low pressure forming just east of FL as advertised by most global's..You can see the discernable spin east of Martin County.

http://radar.weather.gov/radar.php?prod ... B&loop=yes

Just remember that you're looking way above the surface with radar. You're seeing the upper low if you see any spin. I took a look and don't really see anything other than forming/dying showers that may give the illusion of spin.

Here's a link to a radar beam height calculator. At 100nm, for example the beam is looking about 13,000 feet above the surface:

http://www.wdtb.noaa.gov/tools/misc/bea ... width.html

Could be but in any case your right all the energy is now gone east of FL and if anything comes of his mess it will be a fish tale called Chantal.

[hial2]

some convection east of the peninsula. Is that just thunderstorms?

The convection is developing on the trof..on the atmospheric weakness

[wxman57]

some convection east of the peninsula. Is that just thunderstorms?

The convection is developing on the trof..on the atmospheric weakness

What you're seeing is the very top of the wave axis passing to the south of the Yucatan Channel. As the wave axis moves westward at 10-15 mph it causes enhanced lift just to its east. Thus, the small patch of thunderstorms in the Yucatan Channel. But the wave isn't hanging around. Once it passes, there won't be anything left to sustain the thunderstorms. It would take the development of a large, organized mass of thunderstorms developing before the wave axis passes for a chance of TC development. Should such a concentrated mass of storms develop, it could generate inflow/convergence after the wave axis passes. But that's not very likely given the current disorganization of the shower activity and fast movement of the wave. Time is running out.

[NDG]

some convection east of the peninsula. Is that just thunderstorms?

The convection is developing on the trof..on the atmospheric weakness

What you're seeing is the very top of the wave axis passing to the south of the Yucatan Channel. As the wave axis moves westward at 10-15 mph it causes enhanced lift just to its east. Thus, the small patch of thunderstorms in the Yucatan Channel. But the wave isn't hanging around. Once it passes, there won't be anything left to sustain the thunderstorms. It would take the development of a large, organized mass of thunderstorms developing before the wave axis passes for a chance of TC development. Should such a concentrated mass of storms develop, it could generate inflow/convergence after the wave axis passes. But that's not very likely given the current disorganization of the shower activity and fast movement of the wave. Time is running out.

I agree, surface and mid level ridge is moving in fairly fast, I'm surpriesed they still have it as invest.

[wxman57]

Here's a graphic to help understand what's happening out there. I drew in the tropical wave axis in yellow, upper low in light blue, surface trof/old frontal boundary in white dashed line. As the wave moves from east to west, convergence/lift is enhanced east of the wave axis. This is the reason for the flare-up in thunderstorms eat of Nicaragua/Honduras and in the Yucatan Channel. Without the upper low there any more, it takes some mechanism to generate enough lift for thunderstorms (the wave axis). But the wave isn't going to be there much longer, it's on the move to the west at 10-15 mph. Once it leaves, take a look at what's behind it in the central and eastern Caribbean - nothing. So without any other wave/disturbance to enhance lifting along that weak trof, there won't be any concentrated thunderstorms. And without thunderstorms, there can be no TC development.