Extratropical Depression Lee: Inland N Gulf States

[srainhoutx]

The Euro suggests a landfalling Hurricane into S TX...

[srainhoutx]

The 12Z suite so far (NAM, GFS Canadian):

NAM=development S of Lake Charles moving W to WSW
GFS=development S of the general area of New Orleans moving little
Canadian=development S of Lake Charles/Beaumont moving W to WSW along the TX Coast
Forecast=?

We'll see what the Ukmet and Euro spin out a bit later...

Updated:
Ukmet=development S of SW Louisiana moving W to WSW
Euro=development S of SW Louisiana moving W then back E slightly before shifting WSW into S TX

[tireman4]

Are they starting to see a more eastern trend towards FL? Is TX losing this battle? If it continues trending east, TX will get NOTHING!

Again, let me state this. First, I am a amateur weather watcher. Remember, be patient. Still too early to say anything about anything. Wxman57 and Jeff both stated to watch Friday for this ( whatever it is) start doing something. I think this will be a rainmaker for whomever. Also, with the ridge gone, moved or split in two, the door is open for moisture. Rain folks. I think September will be wetter for most. Just my opinion

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or khou.com. For official information, please refer to the NHC and NWS products.

[srainhoutx]

HPC Model Diagnostics Discussion through the operational 12Z Euro:

...DISTURBANCE IN THE GULF OF MEXICO...
PREFERENCE: ENSEMBLE COMPROMISE

FOLLOWING THE SAME TREND AS YESTERDAY...THE NAM REMAINS THE
NORTHERN MOST AND DEEPEST SOLUTION WITH THE LOW PRESSURE SYSTEM IN
THE GULF ON DAY 2. THERE IS LITTLE AGREEMENT AMONGST THE
OPERATIONAL MODELS WITH RESPECT TO THE LOW LOCATION WHEN IT MOVES
INTO THE NORTHERN GULF AND EVENTUALLY ONSHORE. THE 00Z ECMWF AND
CMC TAKE THE LOW INTO TEXAS...BUT THE CMC IS MUCH STRONGER THAN
THE ECMWF. THE 06Z GFS AND 00Z UKMET TAKE THE SYSTEM INTO
LOUISIANA AND MISSISSIPPI...WITH THE UKMET CARRYING THE STRONGER
SOLUTION. THE 12Z NAM STARTS WITH VERY DISORGANIZED SHORTWAVE
ENERGY STRUNG OUT ALONG THE TEXAS...LOUISIANA AND MISSISSIPPI
COASTS AT F48 FRIDAY MORNING...WHICH IS 12 HOURS EARLIER THAN MOST
OTHER OPERATIONAL MODELS INDICATE. THE NAM CONTINUES TO BE ONE OF
THE STRONGEST SOLUTIONS...EVENTUALLY ROTATING THE BULK OF THE
ENERGY WESTWARD INTO EAST TEXAS BY THE END OF THE FORECAST PERIOD.
THE SREF MEAN TENDS TO AGREE WITH THE PLACEMENT OF THE NAM LOW BUT
NOT ON THE STRENGTH...MEANWHILE OTHER ENSEMBLE GUIDANCE LEANS MORE
TOWARDS THE 00Z ECMWF SOLUTION.

THE 12Z GFS HAS SHIFTED THE LOW CENTER TO THE WEST TOWARDS THE 12Z
NAM SOLUTION. THE 12Z GFS HAS ALSO STRENGTHENED FROM THE 06Z
RUN...BUT STILL REMAINS MUCH WEAKER THAN THE NAM. THE 12Z GFS ALSO
PROPAGATES THE LOW CENTER EASTWARD ON DAY 3...WHICH IS THE
OPPOSITE DIRECTION FROM THE 12Z NAM MOVEMENT. THE 12Z UKMET
REMAINS ON THE EAST SIDE OF THE SPREAD WITH THE GFS THROUGH
F48...AND THEN ABRUPTLY CHANGES TRACK AND MOVES TOWARDS THE
CANADIAN/NAM SOLUTION. IN THE SHORT TERM THE 12Z ECMWF HAS TRENDED
SLIGHTLY DEEPER AND EAST OF ITS PREVIOUS TRACK...MOVING ITS
SOLUTION TOWARDS THE NAM CLUSTER.

HOWEVER...WITH THE RIDGE STILL IN PLACE OVER THE SOUTH THAT COULD
IMPACT THE WESTWARD EXTENT OF THIS SYSTEMS MOVEMENT...THE
VARIABILITY OF THE STRENGTH AND TRACK OF THIS SYSTEM FROM RUN TO
RUN WITH ALL OF THE OPERATIONAL GUIDANCE...AND THE PROPENSITY FOR
THE MODELS TO HAVE PROBLEMS NAILING DOWN CYCLOGENESIS...CONFIDENCE
IN THIS CLUSTERING WITH THE NAM/ECMWF IS MARGINALLY LOW THROUGH 48
HOURS AND EVEN LOWER BEYOND F48. DUE TO THE VARYING
SOLUTIONS...HPC IS GOING WITH A CONSERVATIVE SOLUTION BY
RECOMMENDING A TRACK/POSITION CONSISTENT WITH THE BEST CLUSTERING
OF ENSEMBLE GUIDANCE.

[srainhoutx]

Update HPC surface charts suggest this thing is not going to be moving anywhere very fast...

[djjordan]

Just a thought but if 93L did develop into a TD/TS/Cat1 south of Lake Charles and then slowly moved WSW....one must wonder how much rain that is going to sling in. We are talking 3-5 days of rainbands setting up on the dirty side for sure as it heads WSW. That's alot of rain over dry ground. Of course this is all speculation at this point we don't even have a center to work with and that is why models are all over the place ... I'm sure the picture becomes much clearer over the next couple of days as we start to get planes out there and more data to work with.

Not to mention a prolonged storm surge with an E to SE Wind piling water up on the coast and creating a coastal flooding event as well.

[rnmm]

Has a disturbance ever moved WSW in the Gulf? That is where I am confused.

[unome]

http://www.stormpulse.com/tropical-storm-frances-1998

wsw... for a while !

[djjordan]

Has a disturbance ever moved WSW in the Gulf? That is where I am confused.

While it's not typical, there have been systems that move WSW .... wobble around a bit....Move South....It just depends on the steering currents. The steering currents at this time seem to lean in a WSW motion, but that is only right now. Things could change because we really don't have a system quite yet and the upper air data isn't in place yet. The High Pressure ridge off to our North and East is going to be a big player however in steering this future disturbance IMO

[srainhoutx]

Has a disturbance ever moved WSW in the Gulf? That is where I am confused.

Hurricane Anita was a powerful Atlantic hurricane during an otherwise quiet 1977 Atlantic hurricane season. The first tropical cyclone of the season, Anita developed from a tropical wave on August 29 in the north-central Gulf of Mexico. It tracked westward into an area with conditions favorable for further development, and quickly intensified into a hurricane by late on August 30. Initially, Anita was forecast to strike Texas, though a building ridge turned it to the west-southwest. The hurricane rapidly strengthened to attain peak winds of 175 mph (280 km/h), and on September 2 Anita made landfall in eastern Tamaulipas as a Category 5 hurricane. It quickly weakened as it crossed Mexico, and after briefly redeveloping into a tropical depression in the eastern Pacific Ocean, Anita dissipated on September 4 to the south of the Baja California Peninsula.

[rnmm]

Thanks everyone!

[Rip76]

http://www.stormpulse.com/tropical-storm-frances-1998

wsw... for a while !

That track would help a lot of Texans out right now.

[Andrew]

18z NAM shows a LA hit:

http://mag.ncep.noaa.gov/NCOMAGWEB/appc ... mageSize=M

[gregco31]

Is the increased cloud coverage an indication of the High breaking down or moving opening the door for some moisture from this or anything else?

[djmike]

Ok..wow...what a day with these models. I think I have come to the conclusion that this storm will hit Alaska!

The minute I read a post or online article saying the models favor Texas (and get all excited) I find one that says the same models have it going further east favoring central/eastern GOM. I am so ready to pull my hair out as im sure most of you are too aswell.

I am trying my darndest to tell myself to just wait and see. It's hard! But, I think that is the BEST conclusion out of everything that has evolved (so far) today. NO one still knows! I don't think we know anymore today than we did yesterday as far direction.

*Athough I will continue my prayers TX gets atleast some benificial rains. I can handle it not landfalling in TX and I can hanfdle not getting the winds...dear jesus, just please give us some RAIN!

[desiredwxgd]

LCH AFD:

NOW...A TROPICAL WAVE IN THE SOUTHERN GULF WILL MOVE NORTHWARD
AND INTO THE NORTHERN GULF. AT THIS TIME THERE IS NUMEROUS
DIFFERENCES AND SOLUTIONS. OVER ALL IT LOOKS LIKE THE SYSTEM WILL
MOVE TO THE NORTHWEST. THIS WILL INCREASE WINDS AND SEAS IN THE
COASTAL WATERS. THE GOOD NEWS FOR SOUTHEAST TEXAS AND SOUTHERN
LOUISIANA IS IF THE WAVE DOES MOVE IN THIS DIRECTION WE ARE
FINALLY GOING TO GET DESPERATELY NEEDED RAINFALL. THE OTHER PIECE
OF GOOD NEWS IS THAT TEMPS WILL NOT CLIMB INTO THE UPPER 90S...WE
ARE LOOKING AT MID 90S TOMORROW AND UPPER 80S BY SUNDAY. RAINFALL
TOTALS THROUGH THIS PERIOD "THURSDAY THROUGH WEDNESDAY OF NEXT
WEEK" WILL AVERAGE ABOUT ONE TO TWO INCHES ACROSS THE LAKES REGION
AND ABOUT THE SAME FOR CENTRAL LOUISIANA. DOWN TOWARDS THE COAST
ABOUT FOUR INCHES LOOKS ABOUT RIGHT FOR THE I-10 CORRIDOR SOUTH TO
THE COAST.

[Ptarmigan]

Tropical Storm Frances (1998)
http://www.hpc.ncep.noaa.gov/tropical/r ... s1998.html

Frances did move west-southwest and made landfall near Rockport as a tropical storm. Heavy rain throughout Texas and Louisiana.

[srainhoutx]

Afternoon Update from Jeff:

Tropical cyclone formation likely over the NW Gulf of Mexico Friday/Saturday.

Residents along the TX/LA coast should review hurricane preparation plans and be prepared to enact these plans this weekend.

Confidence remains low, but starting to get better model agreement

Models have come into slightly better agreement today on the formation of a tropical system currently located over the SE Gulf of Mexico between SW FL and the Yucatan. Satellite images suggest thunderstorm activity is increasing in this area and NHC has raised the chance of tropical cyclone formation in the next 48 hours to 30%. While there is good agreement on the actual formation of the system, there is poor agreement on where it forms and how it tracks. GFS continues to be the outlier solution showing a low developing off the LA coast and drifting E then NE across FL, this model shows the system getting caught in the trough passing across the northern plains. The GFS looks too deep with the trough and hence the E motion appears unlikely at this time. The ECMWF shows development S of The TX/LA border and then greatly deepens the system all the way down to a strong 968mb hurricane while drifting it W then WSW toward the middle TX coast. The CMC is similar to the ECMWF, but not as strong and more northward toward the upper TX coast. The NAM showing a steady NW motion then a slowing and drift toward the WNW/NW off the SW LA/SE TX coast. Heavy coordination with NHC/HPC and local WFO’s this afternoon are in agreement to lean toward the ECMWF, CMC, NAM, and numerous ensemble members suggesting a low forms over the central or NW Gulf on Friday and then drifts NW this weekend possibly making landfall somewhere on the TX coast, but also just as possible to remain offshore into the middle of next week.

Hard to really hang a forecast without an actual low center yet, where that center develops will be important as to where the system may track.

Intensity
One thing is for sure, models have really jumped upward on the intensity today with several now showing a full blown hurricane in the NW Gulf this weekend. Up to this point, the models have been keeping the system fairly broad and moderate, but now they really want to deepen it. Looking at the factors involved over the NW Gulf: Sea surface temperatures are very warm in the (86-90 degree range), upper level winds are forecast to be somewhat favorable (likely more toward the favorable side than not), however there is a large mass of dry air over TX and LA that could get entrained into the system hindering development. With all that said, you never want to leave a tropical system sitting over the hot Gulf this time of year for any period of time. Not very confident on how strong 93L may become as the models have just recently started showing this stronger trend. Overall things looks fairly favorable for development and development could be fairly quick.

Will continue to stress the very slow expect storm motion and potential for several days of impacts across the NW Gulf.

Impacts:

For now will temper back the model intensities, but follow closely the above mentioned track reasoning and let that help guide the expected impacts. Please understand that confidence is very low and significant changes will be likely over the next 2 days.

Rainfall:
Will start to see moisture increase on Thursday with scattered showers on the seabreeze, then bring rainbands into the coastal areas starting Friday. Will limit the western extent of the rainfall to the US 59 corridor for now. Should confidence build that the system will in fact move more W over the weekend, significant rain chances will be needed for all areas and totals will need to be raised. Widespread rainfall of 2-4 inches is possible S of US 59 Friday-Sunday and this could really be on the conservative side. HPC progs nail the offshore area with 8-12 inches over the weekend!

Tides:
Position of the surface center leads to a prolonged E fetch aimed at the upper TX coast with winds gradually increasing over the northern Gulf starting late Thursday. Large long period swells will begin to arrive on the coast by midday Friday and build into the weekend. Combined effects of large waves and fetch will result in some degree of coastal water level rise. Hard to pin down right now how much and where, but prolonged nature of this event could push a lot of water toward the coast over the weekend.

Winds:
Gradient will tighten into the weekend, how strong and how long is still up for debate, but could see at least TS force winds over the coastal waters starting late Friday and possibly lasting into much of the weekend. For now will not spread this wind inland much due to the uncertainty in the track, but as with the rainfall forecast above, if a westward track does develop, then winds will need to be increased over much of the area. Winds will likely back to the E following the seabreeze on Thursday afternoon and then back to the ENE and NE by Friday evening.

Residents along the TX and LA coasts should continue to closely monitor information on this developing tropical system.

[Ptarmigan]

I agree something will develop. What I don't agree is where it will go. GFS showed Irene near Texas, which never went there.

[biggerbyte]

Well, I am NOT liking the trend with how this whole scenario wants to play out. We've gone from a sure bet change, to not even a 50/50 shot at it. Indications are strong that all, or most of the action stays east of our area. This is subject to change at this point, just as we've changed our confidence level today. Likely a flip flop in thinking from day to day due to the complexity of all the players. I encourage everyone to be ready for anything. The usual don't assume applies. However, a huge disappointment could be in the works, and the dry weather could continue. I'm losing my trees. My lawn is starting to look like a desert. Dispair is grand. Folks, this system had better be the breaker of this pattern. Otherwise.....

God help us here in Texas.