ATL: TROPICAL DEPRESSION ALEX - DISCUSSION

[KWT]

Don't worry I think the NHC aren't sure either AFM, because they are mainly going for a down the middle approach for now to get the best of both worlds so to speak, not a bad approach if your not sure I spose!

Also thanks for uploading the comprasion between Alex/1921 hurricane. Alex is a touch south of that system right now BUT the formation zone is nearly exactly same, as is the landfalling location (nearly perfect!) I really think that maybe a close match...

[jasons2k]

Wow, if the Euro goes the way of the Canadian and GFS, I'm changing my tune in a hurry. If fact, I might get some things tonight just to be prudent. Tomorrow could suddenly get very interesting around here.

[Dean4Storms]

Mike Watkins posted this relevant post over in tropical anaylsis regarding why the GFS and related models are breaking down the ridge enough for the trough to catch Alex.

Crazy thing is that there is already convection building off the LA coast induced from Alex, throw in a Trough and I wouldn't think it is out of the realm that a low could form somewhere along the north coast of the Gulf.

[HURAKAN]

[HurricaneStriker]

Radar imagery from Alvarado. This is as close as I can get to the core of Alex, because the radar site next to Alex's core is shut down. What you see on radar is the southwestern rainbands of Alex.

[ravyrn]

Wow, if the Euro goes the way of the Canadian and GFS, I'm changing my tune in a hurry. If fact, I might get some things tonight just to be prudent. Tomorrow could suddenly get very interesting around here.

I filled up my car and two gas cans today just in case if by some freak act of nature it manages to get close enough up this way. Doubt it happens but after Rita changing its heading at the last minute, one can never be too careful. Never hurts to be prepared

[Air Force Met]

Great image...except IMO your line goes through the MLC. I believe the LLC is actually a little to the NNE of that feature you ID as the low.

I put a dot on your picture...

[xironman]

I drew almost the same line last night on Google Earth based on the two vortex messages from recon.

[jabman98]

Jeez, that stinks. We have very little in hurricane supplies because we're moving in about ten days. We've been paring down so we don't have to move as much stuff. Ugh. I hate the thought of heading out to buy stuff and then having to move it all. Plus, I'm having to do all the packing on my own as my spouse is out of the country. If there was ever a time I would wish for a hurricane to go elsewhere, this would be it.

[KWT]

Crazy thing is that there is already convection building off the LA coast induced from Alex, throw in a Trough and I wouldn't think it is out of the realm that a low could form somewhere along the north coast of the Gulf.

I'd wonder if the development of any low there could well induce some shear on Alex on vice versa...

Certainly would be an interesting solution, maybre that CMC that had two LP's close to each other wasn't so far wrong eh!

AFM, you may actually be right looking at the loops, recon will find out one way or the other sooner rather than later.

[Brent]

[Dean4Storms]

Great image...except IMO your line goes through the MLC. I believe the LLC is actually a little to the NNE of that feature you ID as the low.

I put a dot on your picture...

I agree, you can see the LL clouds swirling back in toward the area you have the dot AFM.

[HURAKAN]

Past Track

[gatorcane]

Mike Watkins posted this relevant post over in tropical anaylsis regarding why the GFS and related models are breaking down the ridge enough for the trough to catch Alex.

Thanks for that post. I agree with MikeW. The GFS solution just doesn't make alot of sense with a "heat low" it wants to develop in the Northern GOM to pinch the trough more SW. Still going with the reliable ECMWF and UKMET on my forecast reasoning. The NHC track may shift some more right but don't expect a massive shift to point at Houston/Galveston and nowhere near as right as the GFS and CMC.

[Brent]

THE PIVOTAL QUESTION FOR THE
LONG-TERM FORECAST TRACK OF THE TROPICAL CYCLONE APPEARS TO HINGE
ON THE STRENGTH OF MID-LEVEL RIDGING OVER THE NORTHERN GULF COAST.
THE MODELS THAT SHOW A WEAKER RIDGE...SUCH AS THE CMC/GFS/HWRF...
ALLOW THE TROPICAL CYCLONE TO TURN TOWARD THE NORTH-NORTHWEST AND
NORTH AND APPROACH THE NORTHWESTERN GULF COAST IN SEVERAL DAYS.
OTHER MODELS...SUCH AS THE ECMWF/UKMET/NOGAPS...HAVE A STRONGER
RIDGE AND KEEP ALEX MOVING TO THE NORTHWEST OR WEST-NORTHWEST INTO
MEXICO. OVERALL THE MODEL GUIDANCE HAS SHIFTED SLIGHTLY TO THE
NORTH...AND THE OFFICIAL FORECAST IS A LITTLE TO THE RIGHT OF THE
PREVIOUS ONE. SINCE THERE IS CONSIDERABLE MODEL SPREAD...THIS TRACK
FORECAST IS THOUGHT TO BE OF BELOW-AVERAGE CONFIDENCE.

[Air Force Met]

Great image...except IMO your line goes through the MLC. I believe the LLC is actually a little to the NNE of that feature you ID as the low.

I put a dot on your picture...

I should have just waited a couple of more minutes. NHC position at 21Z confirms that was the LLC (my dot). Alex now back over water.

[HurricaneStriker]

000
WTNT41 KNHC 272035
TCDAT1
TROPICAL DEPRESSION ALEX DISCUSSION NUMBER 9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL012010
400 PM CDT SUN JUN 27 2010

SATELLITE IMAGES SHOW THAT ALEX CONTINUES TO HAVE A LARGE AND
WELL-DEFINED CIRCULATION WITH PLENTY OF BANDING FEATURES. NEAR THE
CENTER...HOWEVER...CONVECTION HAS DECREASED...PROBABLY DUE TO THE
INFLUENCE OF LAND. THE MEXICAN NAVY SURFACE STATION AT ISLA PEREZ
RECENTLY REPORTED 30 KT WINDS...SO THE INITIAL WIND SPEED IS KEPT
AT 30 KT. AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT IS
SCHEDULED TO INVESTIGATE ALEX THIS EVENING AFTER THE CENTER MOVES
OFFSHORE.

THE INITIAL MOTION OF ALEX IS A LITTLE SLOWER...WITH A 12-HR AVERAGE
YIELDING AN ESTIMATE OF 300/8. THE PIVOTAL QUESTION FOR THE
LONG-TERM FORECAST TRACK OF THE TROPICAL CYCLONE APPEARS TO HINGE
ON THE STRENGTH OF MID-LEVEL RIDGING OVER THE NORTHERN GULF COAST.
THE MODELS THAT SHOW A WEAKER RIDGE...SUCH AS THE CMC/GFS/HWRF...
ALLOW THE TROPICAL CYCLONE TO TURN TOWARD THE NORTH-NORTHWEST AND
NORTH AND APPROACH THE NORTHWESTERN GULF COAST IN SEVERAL DAYS.
OTHER MODELS...SUCH AS THE ECMWF/UKMET/NOGAPS...HAVE A STRONGER
RIDGE AND KEEP ALEX MOVING TO THE NORTHWEST OR WEST-NORTHWEST INTO
MEXICO. OVERALL THE MODEL GUIDANCE HAS SHIFTED SLIGHTLY TO THE
NORTH...AND THE OFFICIAL FORECAST IS A LITTLE TO THE RIGHT OF THE
PREVIOUS ONE. SINCE THERE IS CONSIDERABLE MODEL SPREAD...THIS TRACK
FORECAST IS THOUGHT TO BE OF BELOW-AVERAGE CONFIDENCE.

WHILE THERE IS A LARGE DISAGREEMENT ON THE TRACK OF ALEX...THE
GLOBAL MODELS ARE IN MUCH BETTER AGREEMENT WITH THE LARGE-SCALE
ENVIRONMENT. THESE MODELS SHOW AN UPPER-RIDGE AXIS SITTING VERY
NEAR THE TROPICAL CYCLONE FOR THE NEXT SEVERAL DAYS...IN A
FAVORABLE POSITION FOR INTENSIFICATION. COMBINED WITH THE WARM
WATERS OF THE GULF OF MEXICO...STRENGTHENING IS LIKELY...ESPECIALLY
AFTER ALEX MOVES FARTHER AWAY FROM THE YUCATAN PENINSULA. GIVEN THE
OVERALL ENVIRONMENTAL CONDITIONS...IT IS SURPRISING THAT THE
GFDL/HWRF DO NOT SHOW MORE INTENSIFICATION...LEAVING THE SYSTEM AS
A TROPICAL STORM FOR MANY DAYS. THE STATISTICAL GUIDANCE SEEMS MORE
REASONABLE AND THE NHC FORECAST IS CLOSE TO THE SHIPS MODEL...AND
IS NOT TOO DISSIMILAR FROM THE PREVIOUS FORECAST.

FORECAST POSITIONS AND MAX WINDS

INITIAL 27/2100Z 19.2N 90.9W 30 KT
12HR VT 28/0600Z 19.9N 91.8W 35 KT
24HR VT 28/1800Z 20.6N 92.6W 45 KT
36HR VT 29/0600Z 21.5N 93.3W 55 KT
48HR VT 29/1800Z 22.3N 94.2W 65 KT
72HR VT 30/1800Z 23.2N 96.3W 80 KT
96HR VT 01/1800Z 24.0N 98.5W 55 KT...INLAND
120HR VT 02/1800Z 24.5N 100.5W 20 KT...DISSIPATING INLAND

$$
FORECASTER BLAKE




SUMMARY OF 400 PM CDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...19.2N 90.9W
ABOUT 55 MI...90 KM SSW OF CAMPECHE MEXICO
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/HR
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 9 MPH...15 KM/HR
MINIMUM CENTRAL PRESSURE...999 MB...29.50 INCHES

[Air Force Met]

THE PIVOTAL QUESTION FOR THE
LONG-TERM FORECAST TRACK OF THE TROPICAL CYCLONE APPEARS TO HINGE
ON THE STRENGTH OF MID-LEVEL RIDGING OVER THE NORTHERN GULF COAST.
THE MODELS THAT SHOW A WEAKER RIDGE...SUCH AS THE CMC/GFS/HWRF...
ALLOW THE TROPICAL CYCLONE TO TURN TOWARD THE NORTH-NORTHWEST AND
NORTH AND APPROACH THE NORTHWESTERN GULF COAST IN SEVERAL DAYS.
OTHER MODELS...SUCH AS THE ECMWF/UKMET/NOGAPS...HAVE A STRONGER
RIDGE AND KEEP ALEX MOVING TO THE NORTHWEST OR WEST-NORTHWEST INTO
MEXICO. OVERALL THE MODEL GUIDANCE HAS SHIFTED SLIGHTLY TO THE
NORTH...AND THE OFFICIAL FORECAST IS A LITTLE TO THE RIGHT OF THE
PREVIOUS ONE. SINCE THERE IS CONSIDERABLE MODEL SPREAD...THIS TRACK
FORECAST IS THOUGHT TO BE OF BELOW-AVERAGE CONFIDENCE.

Well...in 1 day we went from high confidence to below average confidence. That's the tropics for you.

[ROCK]

Great image...except IMO your line goes through the MLC. I believe the LLC is actually a little to the NNE of that feature you ID as the low.

I put a dot on your picture...

I should have just waited a couple of more minutes. NHC position at 21Z confirms that was the LLC (my dot). Alex now back over water.

Nice call AFM....we have splash down...

[HurricaneStriker]

They bumped up peak winds with Alex. Rather than 85mph for Wednesday, they bumped it up to 90mph.