ATL : TROPICAL DEPRESSION ALEX - MODELS

[CYCLONE MIKE]

Here are a few exerpts from afd's around the mid-south concerning the front coming down or not

from Memphis...COLD FRONT WILL APPROACH THE MIDSOUTH LATE SUNDAY NIGHT INTO MONDAY.
MODELS CONTINUE TO COME INTO CLOSER AGREEMENT WITH TIMING IN REGARDS
TO FRONT ENTERING THE CWA. HOWEVER THE GFS CONTINUES TO BE THE
FASTER MODEL MOVING THE FRONT THROUGH THE CWA BY TUESDAY 12Z. ECMWF
IS SLOWER KEEPING THE FRONT INTO TUESDAY POSSIBLY TUESDAY EVENING.
WEDNESDAY THROUGH THE END OF THE FORECAST...ECMWF CONTINUES TO BE
THE MODEL OF CHOICE AS IT KEEPS THE RIDGE OVER THE MIDSOUTH. IT
SHOULD BE NOTED THAT THE GFS IS STARTING TO TREND TOWARD THE ECMWF
IN REGARDS TO THE RIDGE. THE RIDGE WILL STRENGTHEN OVER THE AREA
DURING THE TIME PERIOD.

Jackson, MS...FOR SUNDAY...THE UPPER RIDGE BEGINS TO BREAK DOWN AND THE UPPER LOW
OVER THE NORTHERN GULF BEGINS TO LIFT UP TOWARD THE REGION.
THE COLD FRONT SHOULD ARRIVE JUST NORTH OF THE CWA BY TUESDAY
MORNING. THIS WILL PROVIDE A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
THE NORTH THROUGH MONDAY NIGHT. CURRENT MODEL GUIDANCE SHOWS THE
POSSIBILITY FOR MUCH DRIER AIR TO FILTER IN BEHIND THIS FRONT WHICH
WOULD BE A WELCOME SIGHT FOR LOCAL RESIDENTS. /28/

LONG TERM...TUESDAY THROUGH SATURDAY...STRENGTHENING SURFACE HIGH
PRESSURE OVER THE GREAT LAKES REGION FINALLY PUSHES THE FRONT SOUTH
INTO THE ARKLAMISS LATE WEDNESDAY...AND MAY HELP FOCUS SHOWERS AND
THUNDERSTORMS ALONG IT THAT AFTERNOON/EVENING. THURSDAYS CHANCES FOR
CONVECTION WILL BE HIGHEST IN THE SOUTH BASED ON THE FASTER/AND
FURTHER SOUTH/MOVEMENT OF THE FRONT FROM THE ECMWF. IT DOESN`T APPEAR
THE FRONT WILL COMPLETELY PASS SOUTH OF THE AREA THOUGH...AND INSTEAD
LOOKS TO STALL ACROSS SOUTHERN ZONES THROUGH EARLY SATURDAY BEFORE
BEGINNING A RETREAT TO THE NORTH.

And Mobile....LONG TERM [MONDAY THROUGH SATURDAY]...UPPER LEVEL RIDGE REMAINS IN
PLACE OVER THE SE US AND GULF OF MEXICO WELL INTO THE UPCOMING WEEK.
HOWEVER...SOME UNCERTAINTY IN THE UPPER LEVEL PATTERN IS MAKING FOR A
TRICKY LONG TERM FORECAST.

TROPICAL STORM ALEX...CURRENTLY IN THE WESTERN CARIBBEAN...IS
FORECAST TO TRACK WEST-NORTHWESTWARD ACROSS THE YUCATAN PENINSULA
AND THEN REENTER THE SOUTHWEST GULF. THIS TRACK WOULD KEEP THE
SYSTEM WELL SOUTH OF THE AL/FL COASTAL WATERS. THERE ARE A FEW
CONSIDERATIONS TO KEEP IN MIND. WHILE THE UPPER RIDGE DOS LOOK TO
REMAIN IN PLACE...THE WESTERN EDGE ERODES A BIT AS STRONGER
WESTERLIES DIVE SOUTHWARD WITH A LARGE AMPLITUDE TROUGH OVER THE
EASTERN US BY MIDWEEK. THIS MAY ALLOW FOR TS ALEX TO MAKE A MORE
NORTHWARD TURN. THIS SCENARIO IS BECOMING LESS LIKELY BUT STILL ONE
WORTH WATCHING FOR.

[LaBreeze]

Thank you members as always for continuous posting of the model runs as they come. I am positive you have many grateful members here (and pro mets...although they may not wanna admit it) for your continuous service the speed at which you provide this information is second to none.

"Here, here!!" Totally agree ~ great job!

[Ntxwx]

Word is the new gfs is in line with the other models.Does anyone else know about this ?

If by that you mean trending north, yes.

[CYCLONE MIKE]

OK, NOT**** saying this is going to be right, but if it is...alex will explode in the gom...



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deltadog, IF that comes to any sort of fruition do you think Alex could be paying SW LA a visit?

[Extremeweatherguy]

The upgraded GFS differs from the current operational GFS and shows a landfall in northern Mexico:



It does seem to split off some energy towards the northeast though, as can be seen with the second (weaker) low near the FL panhandle.

[Weatherfreak000]

Hmmm...the rest of the model runs at this point are crucial at determining the trend.


Both GFS runs may be equally as effective at this point it could be model wise near 50-50%

[Ivanhater]

Not really a landfall..it seems to decouple along the shore and split off

[Weatherfreak000]

Not really a landfall..it seems to decouple along the shore and split off

That's gotta be somewhat ridiculous. Shear would have to be substantial at the mid levels....is that forecasted?

[CYCLONE MIKE]

Extreme, haven't seen you around much. What is your take on all of this tonight? Compared to the GFS maps IH has been posting to the uprgraded one you just posted. Think there is a chance we could be in for a big surprise come tomorrow night/ monday morning once we see where Alex emerges?

[LaBreeze]

The upgraded GFS differs from the current operational GFS and shows a landfall in northern Mexico:



It does seem to split off some energy towards the northeast though, as can be seen with the second (weaker) low near the FL panhandle.

Could it be that the second (weaker) low near the FL panhandle develops at the tail end of the front? I hope that I'm following this correctly.

[Over my head]

All was well. I went on about my business...Then I catch up reading what I missed... Yes. Crap.

[frederic79]

Somebody probably already brought this up but I've been away for awhile.... If Alex entered the southern gulf and found itself directly under an upper level anticyclone and over very warm water, it could establish a strong central core and possibly bomb under these conditions. Anybody want to speculate on how a stronger Alex would respond to the trough to the north, as opposed to a weaker system? I would have to think, say, a Cat 3 would respond differently than a Cat 1. Thoughts????

[ROCK]

0z CMC is out......another north camper.....great...

lets just muddy the water even more shall we.....


http://www.weatheroffice.gc.ca/data/mod ... 12_108.jpg

[LaBreeze]

Somebody probably already brought this up but I've been away for awhile.... If Alex entered the southern gulf and found itself directly under an upper level anticyclone and over very warm water, it could establish a strong central core and possibly bomb under these conditions. Anybody want to speculate on how a stronger Alex would respond to the trough to the north, as opposed to a weaker system? I would have to think, say, a Cat 3 would respond differently than a Cat 1. Thoughts????

In what way are you thinking that a Cat 3 would respond differently? I have no idea, honestly.

[ROCK]

stalls at the Upper TX coast and just pounds away...piling up water into the bay system....nice

[thetruesms]

So, I'm a few pages behind, but the use of the GFS for boundary conditions on the GFDL has been brought up several times. For an easy way to see how that may be influencing the GFDL, take a look at the GFDN. It's a parallel run of the GFDL, but using NOGAPS for boundary conditions instead of the GFS. Of course, that means you need to be aware of what's going on with the NOGAPS, but it is a quick way of seeing how the accompanying global may be influencing things.

And sometimes, I almost wish the ECMWF would have a slump to remind us that we need to critically evaluate all models rather than just blindly latching onto one and riding it. The key word there being almost

[Ivanhater]

Ah crap..the 2009 winner

[ROCK]

well the 0z GFDL will be out soon enough then the EURO.....boy am I going to feel stupid if it flips...

[Ivanhater]

00z Friday

[wxman22]

Looks like it makes landfall right around Galveston bay...