ATL: TROPICAL DEPRESSION ALEX - DISCUSSION

[ronjon]

Pressure is a dropping.

http://www.ndbc.noaa.gov/show_plot.php?station=42057&meas=wdpr&uom=E&time_diff=-4&time_label=EDT

[KWT]

That bouy isn't in a bad location, esp if the center does decide to form a tighter LLC to the east within the next 24hrs. That being said this is the time of day where pressure is lower anyway right?

[drezee]

Enjoy ladies and gentlemen...you are watching cyclogenesis...pressures are falling like a rock now...LLC will form East of the current 18z position, IMO

It is all relative. For a LLC with no convection this is like a rock. 30mb in 6 hours is only for very well established convective tropical cyclones.

Atmospheric Pressure (PRES): 1007.2 mb
Pressure Tendency (PTDY): -2.2 mb ( Falling )

[Ikester]

That bouy isn't in a bad location, esp if the center does decide to form a tighter LLC to the east within the next 24hrs. That being said this is the time of day where pressure is lower anyway right?

Yes, warmer air during the day is more buoyant than the "cooler" air at night. Still if pressures are falling, it's certainly worth watching...

[Ikester]

Enjoy ladies and gentlemen...you are watching cyclogenesis...pressures are falling like a rock now...LLC will form East of the current 18z position, IMO

Dropping like a rock? Please don't fall victim to media sensationalism. Pressures are down slightly in the area. Like a "rock" would be 30 mb in 6 hours.

[cycloneye]

Enjoy ladies and gentlemen...you are watching cyclogenesis...pressures are falling like a rock now...LLC will form East of the current 18z position, IMO

You may want to clarify that statement with data that we can see,thanks.

[Stormcenter]

Wow this is still one big disorganized mess even with the pressure falls. It looks like it's moving due west or at least the circulation I'm looking at does. I don't know anything for sure with this thing.

does.http://www.ssd.noaa.gov/goes/flt/t1/loop-vis.html

[Ikester]

Here's the recorded data from today at that buoy:

6 24 2:50 pm ENE 7.8 7.8 4.6 7 5.6 - 29.77 -0.04 83.7 84.9 75.9 - - -
06 24 1:50 pm E 9.7 9.7 5.2 8 5.7 - 29.79 -0.02 82.8 84.9 76.8 - - -
06 24 12:50 pm ENE 11.7 15.5 4.9 8 5.7 - 29.81 +0.01 83.1 84.9 77.7 - - -
06 24 11:50 am E 11.7 17.5 5.2 8 5.7 - 29.82 +0.02 81.9 85.1 77.0 - - -
06 24 10:50 am E 11.7 11.7 5.2 8 5.8 - 29.81 +0.02 83.8 84.9 77.0 - - -
06 24 9:50 am E 13.6 15.5 4.6 8 5.3 - 29.80 +0.02 82.6 84.7 77.4 - - -
06 24 8:50 am E 11.7 17.5 4.3 8 5.1 - 29.79 +0.02 83.3 84.7 77.9 - - -
06 24 7:50 am ENE 13.6 15.5 4.3 7 4.8 - 29.79 +0.01 82.9 84.6 77.4 - - -
06 24 6:50 am NE 13.6 15.5 3.9 6 4.9 - 29.78 +0.00 80.8 84.6 78.1 - - -
06 24 5:50 am ENE 13.6 15.5 3.9 6 4.8 - 29.77 -0.03 82.9 84.6 77.5 - - -
06 24 4:50 am ENE 13.6 15.5 3.6 7 4.6 - 29.78 -0.05 82.2 84.6 77.0 - - -
06 24 3:50 am ENE 13.6 15.5 3.3 6 4.5 - 29.78 -0.06 83.3 84.7 77.9 - - -
06 24 2:50 am NE 11.7 17.5 3.6 7 4.8 - 29.80 -0.05 83.7 84.7 78.8 - - -
06 24 1:50 am NE 13.6 13.6 3.3 7 4.8 - 29.83 -0.02 84.2 84.7 77.9 - - -
06 24 12:50 am ENE 9.7 11.7 3.3 7 4.7 - 29.84 +0.00 83.8 84.9 78.6 - - -
06 23 11:50 pm NNE 13.6 15.5 3.3 6 4.7 - 29.85 +0.01 84.6 85.1 78.3 - - -
06 23 10:50 pm NNE 13.6 17.5 3.0 6 4.3 - 29.84 +0.01 83.8 85.1 78.4 - - -
06 23 9:50 pm N 11.7 17.5 3.0 6 4.8 - 29.84 +0.03 83.3 85.1 77.9 - - -
06 23 8:50 pm NNE 11.7 13.6 3.3 7 5.1 - 29.84 +0.03 85.1 84.6 77.5 - - -
06 23 7:50 pm N 9.7 13.6 3.6 6 5.3 - 29.83 +0.01 83.3 85.3 78.4 - - -
06 23 6:50 pm ENE 5.8 5.8 3.3 5 5.2 - 29.81 -0.03 84.2 85.6 77.5 - - -
06 23 5:50 pm NE 7.8 9.7 2.6 6 4.8 - 29.81 -0.04 83.7 86.0 77.5 - - -
06 23 4:50 pm NE 5.8 7.8 2.6 5 4.8 - 29.82 -0.05 85.3 85.6 76.8 - - -
06 23 3:50 pm ENE 5.8 7.8 2.6 7 4.9 - 29.84 -0.05 85.1 85.6 76.1 - - -

As you can see, pressures have been nearly unchanged for the day. Fluctuations are within the average. Due to thunderstorms in the area, microclimate could affect the pressures being that t-storms are in the vicinity. You can't have rising or sinking air everywhere. So it may be in an area of rising air currently. Now if the pressure continue their downward trend, then you'll have my attention.

[Stormcenter]

This is an excerpt from this afternoon's NWS discussion out of New Orleans, LA. concerning 93L.

CONCERNING A TROPICAL WAVE IN THE CARIBBEAN...THE NATIONAL HURRICANE CENTER IS FORECASTING 40 PERCENT CHANCE OF THE WAVE DEVELOPING INTO A TROPICAL DEPRESSION OVER THE NEXT 48 HOURS. FORECAST MODELS ARE GENERALLY TAKING ANY LOW PRESSURE CENTER
FORMING OVER THE CARIBBEAN WELL TO THE WEST AND SOUTH OF LOUISIANA DURING MID TO LATE NEXT WEEK. FOR THE LATEST NATIONAL HURRICANE CENTER FORECASTS SEE http://WWW.NHC.NOAA.GOV.

[bahamaswx]

Looks to be falling like a rock to me.

[tailgater]

The pressure dropped more than 3mbs in the last 24hr period is what I usally look for.

[Ivanhater]

From JB

THURSDAY 2:15 PM
DOWN GOES THE DC RECORD


The system in the western Caribbean has its low-level center west of the mid-level center. This is not from shearing, but simply because it's the way the pattern is evolving. This should be a tropical storm by the time it reaches the Yucatan Saturday night or Sunday.

Ciao for now. ****

[Ikester]

Houston's thoughts:

UPPER TROUGH OVER THE
EASTERN U.S. POSES ISSUES WITH GFS/ECMWF SOLUTIONS AND THE
EVENTUAL TRACK OF THE TROPICAL WAVE/MOISTURE IN THE CARIBBEAN.
HAVE TENDED THE FORECAST TOWARD THE ECMWF SOLUTION WITH PRESSURE
FALLS OVER THE SW GULF AND THE TRACK OF THE TROPICAL SYSTEM
TOWARDS SOUTH TEXAS AND EXT NERN MEXICO. SO EXPECT WARMER AND
DRIER WEATHER SATURDAY THROUGH MONDAY THEN CONFIDENCE DROPS
QUICKLY AND HAVE GONE WITH OR BELOW MEX TEMPERATURE GUIDANCE
NUMBERS AND WILL CONTINUE THE SLIGHT OR CHANCE POPS FOR TUESDAY
AND BEYOND. DO NOT EXPECT THE FRONT THAT GFS IF PROGGING TO MOVE
INTO THE AREA WEDNESDAY OR THURSDAY NEXT WEEK TO MAKE IT THIS FAR
SOUTH UNLESS TROPICAL SYSTEM WRAPS UP AND STAYS ON A MORE
SOUTHERLY TRACK.

[txagwxman]

I think the ECMWF has the general idea...strengthens rapidly once it crosses over the Yucatan into the Western Gulf, if it can develop a core system before it hits the Yucatan. Otherwise it will probably be disorganized and slow to re-develop after it crosses. 1007 mb is a signficant low in the tropics with no convection.

[wxman57]

http://www.ndbc.noaa.gov/plot_wind_pres.php?station=42057&uom=E&time_diff=-4&time_label=EDT

Looks to be falling like a rock to me.

Take a look at the trace from all week - the pressure drops like that every afternoon. It just started from a little lower point today because the wave axis is nearby.

[HURAKAN]

Convection getting closer to the center

[johngaltfla]

From JB

THURSDAY 2:15 PM
DOWN GOES THE DC RECORD


The system in the western Caribbean has its low-level center west of the mid-level center. This is not from shearing, but simply because it's the way the pattern is evolving. This should be a tropical storm by the time it reaches the Yucatan Saturday night or Sunday.

Ciao for now. ****

Thank you Ivanhater. Saved me a trip to JB's. This is an amazing start to the season even though nothing has happened. I can't remember the last time we had June Invests from the Central Atlantic with this much interest moving this far.

[Ikester]

Well 14 storms isn't an epic season but 23 would be. There is a huge range there and the fact that the E. Pac is jumping signals to me that the Atlantic will be quiet for a bit longer.

[crimi481]

From a distance (Atl WV loop) - you can see the over all shape of forming system, and how the larger blob in center (s. of Haiti) "fits" visually within the "shrimp"(#9) shape. Right where the "hook" should be. System is huge,may be strong one.
May curve to Fl Panhandle if strong
.

http://www.ssd.noaa.gov/goes/east/tatl/loop-wv.html

[HURAKAN]

Accuwx's take