Extratropical Depression Lee: Inland N Gulf States

[srainhoutx]

By early Wednesday morning, the low is ESE of Brownsville...

[kellybell4770]

well crap.

[biggerbyte]

That scenario, which is a possible one, does not favor our area. High builds back in, tropical mischief stays east and south, we get a dry flow between the tropical system and the ridge. Result is continued hot and dry. There has even been some talk here and there of a front coming down, which would further prevent any tropical system from getting to us. Lovely! This is only one scenario, folks, but it's there. Nothing is for sure yet. I should go ahead and mention that the NWS is already losing confidence in rainfall, in the short term, at least. We are down from 60%/50% to 30% and 40% chances. We can expect wavering in the forecast for a bit.

[srainhoutx]

For what it's worth, the 12Z Canadian...

[djjordan]

Wouldn't pay too much attention to any one model .... this system would be a much better scenario for us however if it comes in as a Tropical Wave and doesn't develop anytime soon. We all know not to discount any type of scenario this time of year in the GOM. Don't let these models discourage you folks they will continue to come up with different solutions with every run .....

[rnmm]

Mentioned in the TWO: 10%

337
ABNT20 KNHC 301734
TWOAT

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT TUE AUG 30 2011

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON TROPICAL
STORM KATIA...LOCATED ABOUT 630 MILES WEST-SOUTHWEST OF THE
SOUTHERNMOST CAPE VERDE ISLANDS.

A TROPICAL WAVE OVER THE NORTHWESTERN CARIBBEAN SEA IS ACCOMPANIED
BY DISORGANIZED CLOUDINESS AND SHOWERS. THIS SYSTEM IS EXPECTED TO
MOVE GENERALLY WESTWARD AT 10 TO 15 MPH ACROSS THE YUCATAN
PENINSULA DURING THE NEXT DAY OR TWO...AND HAS SOME POTENTIAL FOR
DEVELOPMENT OVER THE WESTERN GULF OF MEXICO IN A FEW DAYS. THIS
SYSTEM HAS A LOW CHANCE...10 PERCENT...OF BECOMING A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER PASCH

[djjordan]

Well we all know this board is gonna be ramping up as the week goes by. Gonna be an interesting weekend to say the least.

[srainhoutx]

The 12Z Euro has backed down regarding any early development. That model suggests an open wave/inverted trough through hour 72...

[srainhoutx]

The Euro through hour 144 keeps a possible monsoonal depression down near S TX/NE MX. That model never really strengthens to a true closed low, for what it's worth...

[srainhoutx]

By hour 216...(long range)... the Euro suggests a low does form while being pushed S into the Bay of Campeche with the front.

[srainhoutx]

HPC Model Diagnostics Update through the 12Z Euro:

...CENTRAL GULF OF MEXICO DISTURBANCE...
PREFERENCE: 12Z ECMWF/12Z GFS

THE NAM IS ON THE NORTHERN SIDE OF THE SPREAD WITH THIS SYSTEM.
THE UKMET AND THE NAM ARE BOTH STRONG WITH MID-LEVEL ENERGY MOVING
INTO THE GULF BUT THE 00Z UKMET KEEPS THE CENTER OF THE
DISTURBANCE SOUTH AND WEST OF THE 12Z NAM. BOTH THE 06Z GFS AND
00Z ECMWF ARE SLOW TO DEVELOP THIS DISTURBANCE AT THE UPPER
LEVELS...WITH THE FIRST DISCERNIBLE INDICATION OF THE DISTURBANCE
NOT POPPING UP UNTIL THE DAY 3 TIME PERIOD. AT THE SURFACE WEAK
LOW PRESSURE IS INDICATED BY THE GFS AND ECMWF...STAYING WELL TO
THE SOUTH AND MUCH WEAKER THAN THE NAM/UKMET. THE 12Z NAM SHOWS A
VERY DEEP AND STRONG SOLUTION ON DAY 3...MAKING ITS SOLUTION AN
OUTLIER AMONGST OTHER OPERATIONAL AND ENSEMBLE SOLUTIONS. THE 12Z
GFS HAS TRENDED NORTHWARD TOWARDS THE NORTHERN SOLUTIONS BUT IS
STILL FURTHER SOUTH THAN THE NAM AND MUCH WEAKER. THE 12Z UKMET
HAS WEAKENED THE SURFACE LOW AND HAS SHIFTED FURTHER SOUTH...MORE
IN LINE WITH THE 00Z ECMWF. IT IS STILL ONE OF THE WESTERN MOST
OPERATIONAL SOLUTIONS. THE 12Z ECMWF IS COMPARABLE TO ITS 00Z
RUN...PERHAPS SLIGHTLY WEAKER DEPTH WISE BUT THE LOW CENTER IS
STILL IN A SIMILAR LOCATION.

[srainhoutx]

A repost that I made in the Labor Day Weekend weather thread on the main page. Updated HPC extended surface charts are out: (note the stalling frontal boundary depicted to the N of our area)...

[Rip76]

Just off the coast far enough to spare us from rainfall?

[Met Tech]

In the 12Z GFS, the storm looks like it is trapped in a padded room being chased around by rabid squirrels.

It'll be a slap in the face if that front comes in strong enough to blast everything to the south before it does any good.

[am19psu]

Gah. How did this storm go from a quick spin up to a monsoon depression. What a mess. Hopefully y'all can get some better rains than currently modeled out of this.

[djjordan]

I don't think anyone is really taking into account the enormous amount of moisture that will stream in if that "weak" low actually does verify and meander around down there. The moisture combined with the front from the north will squeeze out some heavy downpours along the Texas Gulf Coast. Just my two cents.

[Met Tech]

I don't think anyone is really taking into account the enormous amount of moisture that will stream in if that "weak" low actually does verify and meander around down there. The moisture combined with the front from the north will squeeze out some heavy downpours along the Texas Gulf Coast. Just my two cents.

True enough. My hometown is between San Antonio and Del Rio, where it looks like Mars right now. I'm hoping to have some frontal lift/tropical moisture combination go to work out there, but it's not looking too promising (from this far out anyway).

[srainhoutx]

I'm already seeing some ramp up in discussions from New Orleans to Brownsville. Coastal effects are most noteable right now and the HPC is ramping up as well. Should make for an interesting long Holiday Weekend and early next week regardless...

OVER THE WRN GULF OF MEXICO... THERE IS CURRENTLY NO FEATURE FOR
WHICH THE NHC TROPICAL WEATHER OUTLOOK INDICATES CONCERN FOR
POTENTIAL DEVELOPMENT DURING THE NEXT TWO DAYS. HOWEVER BY THE
MEDIUM RANGE PERIOD THE AVERAGE OF ALL GUIDANCE OVER THE PAST 24
HRS HAS TRENDED STRONGER WITH A MID LVL WEAKNESS/POSSIBLE CLOSED
LOW AND ASSOC SFC LOW OVER THE WRN OR NRN GULF. THE 00Z AND YDAYS
12Z ECMWF RUNS WERE ON THE AGGRESSIVE SIDE OF THE ENVELOPE WITH
ITS DEVELOPMENT BUT THE NEW 12Z RUN IS MUCH WEAKER/MORE
SUPPRESSED. THE 06Z/12Z GFS ARE ON THE NERN SIDE OF THE ENVELOPE.
THE FINAL FCST INCORPORATES THE 17Z NHC/HPC COORDINATION FOR
TRACK/STRENGTH WITH AN INTERMEDIATE SOLN RECOMMENDED FOR BOTH
PARAMETERS.



THE FOCUS FOR HEAVIEST RNFL DURING THE PERIOD WILL LIKELY BE ALONG
THE GULF COAST IN ASSOC WITH THE BROAD AREA OF LOW PRESSURE FCST
TO EVOLVE OVER THE WRN HALF OF THE GULF OF MEXICO. CONFIDENCE IN
WHERE THE GREATEST IMPACT WILL BE IS FAIRLY LOW DUE TO THE CURRENT
SPREAD AMONG MODEL/ENSEMBLE SOLNS. MEANWHILE A SERIES OF FRONTS
WILL PROGRESS ACROSS THE CNTRL-ERN STATES... ACCOMPANIED BY
SHWRS/TSTMS OF VARYING INTENSITY.

[jeff]

something is likely to develop in the Friday-Sunday period. Where is goes and how strong is up for much debate. HPC progs are really pushing the heavy rainfall well east of the coordinated NHC/HPC points. I think they may be too far east/north. Watch out for a coastal flooding event with a slow moving/stalled system for several days leading to a gradual increase in tides and seas over several tide cycles (TS Frances 98). Leaving anything over the NW Gulf this time of year is cause for at least some concern.

[Ptarmigan]

If this storm was like Frances of 1998, it would be a huge rainmaker and large storm. As for where it goes, too early to tell until it develops.