SE TX/SW LA weather: Much cooler and WET after Tuesday

[Ptarmigan]

Looks like this will be a big storm. I know the March 1992 and May 1989 flood had a strong low pressure system over the Four Corners.

[srainhoutx]

HGX Update. One of the stronger worded AFD's I seen in a while...

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
247 PM CDT WED OCT 28 2009

.DISCUSSION...
IT HAS BEEN A NICE QUIET WEATHER DAY ACROSS SOUTHEAST TEXAS TODAY WITH
MODERATE TO STRONG SOUTH TO SOUTHEAST WINDS ACROSS THE AREA. TEMPERATURES
HAVE WARMED INTO THE LOWER 80S ACROSS SOME SPOTS...AND MOISTURE LEVELS
CONTINUE TO RISE WITH DEW POINTS SURGING INTO THE LOWER 70S. THE ONSHORE
FLOW WILL PERSIST...AND THIS WILL SET THE STAGE FOR A DESTABILIZING
AIRMASS ACROSS SOUTHEAST TEXAS BEGINNING TONIGHT AND PERSISTING ON INTO
AT LEAST FRIDAY MORNING. CHANCES FOR SHOWERS AND THUNDERSTORMS BEGIN
TO INCREASE TONIGHT...AND THERE WILL BE AN INCREASING RISK FOR STRONG
TO SEVERE THUNDERSTORM DEVELOPMENT DURING THE DAY ON THURSDAY AS A STRONG
LOW LEVEL JET AND INCREASING SHEAR DEVELOP ACROSS THE AREA. STRONG DAMAGING
WINDS AND ISOLATED TORNADOES WILL BE THE PRIMARY SEVERE WEATHER THREAT.
THE RISK FOR HEAVY RAINFALL COMES INTO THE PICTURE BEGINNING EARLY TOMORROW.
THE DEEPENING MID/UPPER LEVEL LOW NOW IN THE FOUR CORNERS AREA WILL
MAKE SLOW EASTWARD PROGRESS...AND THIS SPEED IN COMBINATION WITH AN
ASSOCIATED SLOW MOVING COLD FRONT...VERY VERY VERY VERY GOOD LOW LEVEL
CONVERGENCE ALONG THE SURFACE AND 850 MB FRONTS...AND PRECIPITABLE WATER
VALUES EXCEEDING 2 INCHES WILL SET THE STAGE FOR THE HEAVY RAIN THREAT
TO LIKELY PERSIST ON INTO THE OVERNIGHT HOURS ON THURSDAY NIGHT AND
FRIDAY MORNING. A FLASH FLOOD WATCH IS IN EFFECT FROM TOMORROW MORNING
THROUGH TOMORROW EVENING...AND WE WILL PROBABLY NEED TO EXTEND THE WATCH
INTO THURSDAY NIGHT AND FRIDAY MORNING WHEN THE FRONT CREEPS THROUGH
SOUTHEAST TEXAS. WIDESPREAD RAINFALL TOTALS OF 1 TO 3 INCHES WITH ISOLATED
TOTALS EXCEEDING 5 INCHES CAN BE EXPECTED. THE GROUND REMAINS WET AND
AREA RIVERS...CREEKS AND BAYOUS REMAIN ELEVATED. LOCATIONS GETTING RAINFALL
TOTALS APPROACHING A 3 TO 5 INCH RANGE WILL LIKELY HAVE FLOODING PROBLEMS.
MUCH COOLER TEMPERATURES AND DECREASING RAIN CHANCES COME ON FRIDAY
AS THE FRONT MOVES OFF TO THE EAST. WHILE THE RISK FOR HEAVY RAINFALL
MOVES ON OUT...ELEVATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE BEHIND
THE FRONT AS THE UPPER LEVEL TROUGH LAGS BEHIND. THIS WEATHER EVENT
WILL COME TO AN END BY FRIDAY NIGHT. COOL NIGHTS AND MILD DAYS ALONG
WITH JUST A FEW CLOUDS AND NO RAIN CAN BE EXPECTED OVER THE WEEKEND.
42

[JenBayles]

I can only hope that history repeats itself in that widely advertised events tend to bust. We can deal with 5" rainfall - if it doesn't dump all at once. Is it Saturday yet?

[srainhoutx]

E-mail from Jeff this evening...

Very rough 48 hours on tap for TX.

Threats include: Flash Flooding, river/bayou flooding, urban flooding, tornadoes, high winds, coastal flooding

Discussion:
Powerful upper trough digging into the SW US. Upper air analysis from the western US shows 150kt jet still digging on the backside of this system suggesting a slower eastward movement and deeper southward track. Across TX, rapid moisture has returned with dewpoints now in the 70's over most of SE TX and the mid 70's over Matagorda Bay. Low level jet has developed in response to surface pressure falls over the TX panhandle being forced by incoming upper level storm system. Low level jet is expected to increase to near 45kts this evening with progged 850mb winds increasing to near 60-65kts early Thursday pumping 2.0+ inch PWS into the region.

Radar is starting to show scattered showers developing as moisture deepens. Expect a nearshore coastal marine boundary to establish this evening and may focus strong thunderstorm development after midnight, although this is uncertain at this time.

Thursday:
Warm sector air mass will be well established as lift begins to overspread from the west. Expect numerous thunderstorms to develop by morning and train NNE across the area. Low level shear values increase and expect some storms to become severe with mesocyclone formation promoting tornado genesis. While instability is lacking, the amount of wind energy is suggestive of both tornadoes and damaging straight line winds. Storms will be excessive rainfall producers as warm saturated layer promotes warm rainfall production with moisture levels over 200% above late October normals.

Thursday night:
Strong cold front will reach the area and slow down as upper winds become parallel to the boundary. Expect a large squall line to develop Thursday midday along I-35 and track eastward while slowing in forward motion. Discrete storms developing ahead of this main line and rooted near the surface will have a tornado threat while the line itself will have a straight wind damage threat given strong mid level flow punching around the base of the upper trough. Main concern is rainfall and flash flooding given slowing forward storm motions and high threat for cell training. Impressive low level flow will continue to pump tremendous moisture into the line of convection allowing an extended period of excessive rainfall. Not sure where the line will slow the most, and it remains possible that stronger outflow winds may be enough to force the main line off the coast much like Monday.

Friday:
Upper trough will lag behind the main front back over New Mexico allowing good moisture supply to be lifted up and over the top of the surface cold dome promoting strong isentropic ascent and moderate rainfall nearly all day Friday. Cold air advection at the surface along with strong N winds,clouds and rainfall will make for a cold day with temps. steady in the 50's. Rain will end from west to east Friday evening and skies clear by Saturday morning making for a nice Halloween.

Rainfall:
Have upped QPF numbers from this morning based of 12Z guidance and newly released HPC guidance. HPC shows an impressive 24hr bulls-eye of over 5.0 inches over Polk County with a widespread 3-4 inches from Matagorda to Harris to San Jacinto County. Will go with widespread amounts of 2-4 inches with isolated totals of 5-8 inches possible. Given low flash flood guidance values, saturated grounds, and swollen/flooding rivers rainfall of this magnitude will cause significant run-off and flooding. High hourly rainfall rates will produce urban flash ponding/street flooding and produce significant rises on area bayous and creeks.

Severe Threat:
Will look for a tornado threat during the day Thursday mainly E of a Palacios to Columbus to CLL line where shear will be greatest and surface moisture influx the strongest. Wind threat will increase late in the day as linear line approaches from the W/NW with leading edge wind damage potential. Given extremely moist layer and high freezing levels, hail should be isolated in nature. Events such as this in the past have supported more tornadoes than anything (11-17-03 event)

Coastal Flooding:
Strong onshore SE winds will result in building long period swells tonight. Large swells will add significant water to the beach front and trap outgoing high tides mainly from Galveston County E into SW LA. Tides will run 3-4 feet above normal. Tides at these levels combined with large wave action will result in some flooding of low lying areas on Bolivar and possible wave splash over on HWY 87. More significant impacts may be felt in SW LA.

Hydro:
River flooding is forecast or in progress on several area rivers. Forecasted widespread QPF over much of the area river basins will promote additional rises going into this weekend and may force some channels into major flooding. Given current rainfall projections feel the main concern will be the Brazos, San Jacinto, and Trinity basins especially since the lower Trinity and lower Brazos are already forecast to go into minor/moderate flooding even without this additional rainfall.

[jasons2k]

Was just outside doing some yard work, and within the last hour or so the LLJ has really cranked-up & the clouds are screaming to the NNW now. I can already tell this one's gonna be more potent than that last system.

[JenBayles]

You know it's bad when Jeff sends out a discussion in the evening. Sounds like the only thing we WON'T have is ice.

[Ptarmigan]

Severe Threat:
Will look for a tornado threat during the day Thursday mainly E of a Palacios to Columbus to CLL line where shear will be greatest and surface moisture influx the strongest. Wind threat will increase late in the day as linear line approaches from the W/NW with leading edge wind damage potential. Given extremely moist layer and high freezing levels, hail should be isolated in nature. Events such as this in the past have supported more tornadoes than anything (11-17-03 event)

This should be an interesting event to watch. Here is something about that outbreak.

http://www.srh.noaa.gov/hgx/projects/nov17_03.htm

SYNOPSIS

A strong 500mb upper level trough of low pressure over the western U.S. was moving from west to east across the southern plains. The polar jetstream associated with the 500 millibar trough surged into west Texas and then curved sharply to the northeast into the Central Plains. The sub-tropical jetstream was oriented west to east across Deep South Texas. The jetstream pattern is strongly divergent and is frequently an ingredient in severe weather. Low level moisture had been increasing and was about 200 percent of normal by 6 AM Monday morning. Vertical wind profiles also showed a great deal of wind shear or low level turning of the winds with height. This turning was particularly pronounced in the lowest 2000 feet of the atmosphere. In addition, wind speeds increased rapidly with height. Wind speed and directional shear are two important parameters necessary for tornadic thunderstorms. Lastly, a weak low level boundary was aligned from southwest to northeast generally along the U.S. Highway 59 corridor. This provided a focus for thunderstorm development. This feature was nearly stationary and thunderstorms repeatedly developed and moved along this boundary. The axis of heaviest rain was coincident with this nearly stationary boundary.

Looks eerily similar.

[vbhoutex]

You know it's bad when Jeff sends out a discussion in the evening. Sounds like the only thing we WON'T have is ice.

Oh sweet. More good news for the next few days!!!

[HouTXmetro]

Very similar

http://radar.weather.gov/radar.php?prod ... X&loop=yes

I'm kind of confused. The inland showers are moving N-NNW while the coastal showers are moving NNE-NE.

[vbhoutex]

Very similar

http://radar.weather.gov/radar.php?prod ... X&loop=yes

I'm kind of confused. The inland showers are moving N-NNW while the coastal showers are moving NNE-NE.

Warm sector beginning to move N while showers out to South of front/trough still moving along it to NE.

[srainhoutx]

HGX Update tonight. Looks busy starting early tomorrow...

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
853 PM CDT WED OCT 28 2009

.DISCUSSION...
SEEING SCT SHOWERS THIS EVENING AS MOISTURE DEEPENS AND THE
ATMOSPHERE BEGINS TO DESTABILIZE. WILL LIKELY SEE A FEW TSTMS
LATER TONIGHT. FOR THE UPDATE NUDGED MIN TEMPS UP A LITTLE
AND ALSO BUMPED UP WIND SPEEDS. THE 50 POP LOOKS OK FOR THE
CONTINUED SCT ACTIVITY TONIGHT. STILL LOOKS LIKE A BUSY
THURSDAY AND THURSDAY NIGHT ON TAP WITH ABUNDANT TROPICAL
MOISTURE IN PLACE IN AN UNSTABLE ATMOSPHERE AND A POTENT STORM
SYSTEM APPROACHING. MAY NEED A WIND ADVISORY TOMORROW AS THE
PRESSURE GRADIENT TIGHTENS...WILL CONTINUE TO MONITOR. 33

[HouTXmetro]

Very similar

http://radar.weather.gov/radar.php?prod ... X&loop=yes

I'm kind of confused. The inland showers are moving N-NNW while the coastal showers are moving NNE-NE.

Warm sector beginning to move N while showers out to South of front/trough still moving along it to NE.

Can you give me a quick explanation of what a warm sector is? Secondly with the boundary of the opposite moving storms within about 100 or so miles, is that why we are under a threat of tornadic activity?

[vbhoutex]

Very similar

http://radar.weather.gov/radar.php?prod ... X&loop=yes

I'm kind of confused. The inland showers are moving N-NNW while the coastal showers are moving NNE-NE.

Warm sector beginning to move N while showers out to South of front/trough still moving along it to NE.

Can you give me a quick explanation of what a warm sector is?

If I am correct in what I am seeing and saying the front that came through here the other day is now moving back to the north. We are actually not in the warm sector yet(ie the warmest air)but probably will be by in the morning. That is what is bringing the moisture in. What we may be seeing is the overriding moisture getting lift as it goes North of the front and therefore generating showers moving N or NW while the showers moving NE are still on the South side(warm side/sector) of the front and moving NE with the flow of the trough. I am not totally positive on this but I know it is similar to what I have explained. Any pro or better amateur feel free to correct me.

[HouTXmetro]

Thanks, kinda makes sense.

[vbhoutex]

Think of a line between the two sets of showers that are moving in different directions. That would be the warm front returning North. Due to the very strong upper level winds we apparently are getting overruning of moisture from the South that is also getting lifted which is producing the showers moving N or NNW. The showers South or Southeast of that line/front are moving NE because the air in front of the front moves in that direction at the surface(in front of any front advancing W-E or N-S.

[srainhoutx]

There is also a moisture tap from a disturbance off the W Coast of MX riding the Sub Tropical Jet. HGX Entends FFW through Friday AM...

FLOOD WATCH
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
908 PM CDT WED OCT 28 2009

TXZ163-164-176>179-195>200-210>214-226-227-235>238-291200-
/O.EXT.KHGX.FF.A.0002.091029T1200Z-091030T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
AUSTIN-BRAZORIA-BRAZOS-BURLESON-CHAMBERS-COLORADO-FORT BEND-
GALVESTON-GRIMES-HARRIS-HOUSTON-JACKSON-LIBERTY-MADISON-MATAGORDA-
MONTGOMERY-POLK-SAN JACINTO-TRINITY-WALKER-WALLER-WASHINGTON-
WHARTON-
INCLUDING THE CITIES OF...ALVIN...ANAHUAC...ANGLETON...BAY CITY...
BELLVILLE...BRENHAM...BROOKSHIRE...BRYAN...CALDWELL...CLEVELAND...
COLDSPRING...COLLEGE STATION...COLUMBUS...CONROE...CORRIGAN...
CROCKETT...DAYTON...EAGLE LAKE...EDNA...EL CAMPO...FREEPORT...
FRIENDSWOOD...GALVESTON...GROVETON...HEMPSTEAD...HOUSTON...
HUMBLE...HUNTSVILLE...KATY...LAKE JACKSON...LAKE SOMERVILLE...
LEAGUE CITY...LIBERTY...LIVINGSTON...MADISONVILLE...
MISSOURI CITY...MONT BELVIEU...NAVASOTA...ONALASKA...PALACIOS...
PASADENA...PEARLAND...PIERCE...PRAIRIE VIEW...RICHMOND...
ROSENBERG...SEALY...SHEPHERD...SUGAR LAND...TEXAS CITY...
THE WOODLANDS...TOMBALL...TRINITY...WEIMAR...WHARTON...WILLIS...
WINNIE
908 PM CDT WED OCT 28 2009

...FLASH FLOOD WATCH NOW IN EFFECT FROM 7 AM CDT THURSDAY THROUGH
FRIDAY MORNING...

THE FLASH FLOOD WATCH IS NOW IN EFFECT FOR

* A PORTION OF SOUTHEAST TEXAS...INCLUDING THE FOLLOWING
COUNTIES...AUSTIN...BRAZORIA...BRAZOS...BURLESON...CHAMBERS...
COLORADO...FORT BEND...GALVESTON...GRIMES...HARRIS...HOUSTON...
JACKSON...LIBERTY...MADISON...MATAGORDA...MONTGOMERY...POLK...
SAN JACINTO...TRINITY...WALKER...WALLER...WASHINGTON AND
WHARTON.

* FROM 7 AM CDT THURSDAY THROUGH FRIDAY MORNING

* EXCESSIVE RAINFALL FROM SHOWERS AND THUNDERSTORMS IS EXPECTED TO
DEVELOP AHEAD OF AND ALONG A SLOWLY ADVANCING COLD FRONT. THIS
ACTIVITY IS EXPECTED TO IMPACT SOUTHEAST TEXAS BEGINNING AS
EARLY AS THURSDAY MORNING AND PERSISTING THROUGHOUT THE DAY.
ADDITIONAL STORMS ARE EXPECTED TO FOCUS ALONG THE SLOW MOVING
COLD FRONT THAT MOVES INTO AND THROUGH SOUTHEAST TEXAS THURSDAY
NIGHT AND FRIDAY MORNING. SOME STORMS ARE LIKELY TO TRAIN OVER
THE SAME AREAS ADDING TO THE POTENTIAL FOR FLASH FLOODING. MOST
AREAS CAN EXPECT 2 TO 4 INCHES OF RAINFALL WITH ISOLATED AREAS
EXPECTED TO RECEIVE 5 TO 8 INCHES. WITH THE GROUND ALREADY
SATURATED...THIS ADDITIONAL RAINFALL WILL LIKELY CAUSE FLOODING
PROBLEMS.

* RUNOFF FROM ANY HEAVY RAINFALL ACROSS SOUTHEAST TEXAS WILL
IMPACT ALREADY SWOLLEN RIVERS...STREAMS AND CREEKS. THIS MAY
CAUSE ADDITIONAL RISES IN RIVERS AND MORE RIVER FLOODING.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD
TO FLASH FLOODING. FLASH FLOODING IS A VERY DANGEROUS SITUATION.

YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION
SHOULD FLASH FLOOD WARNINGS BE ISSUED.

[southerngale]

They issued a Flood Watch here this morning as well, for Thursday morning through Friday evening. Also, a wind advisory and coastal flood advisory. Hello, El Nino.

We were outdoors tonight and we got rained on a little... it was mostly a drizzle, with a little light rain mixed in here and there, but even that was spotty with it starting and stopping often. But boy was it windy!! The clouds looked almost spooky... dark and ominous. Maybe it was the Halloween in me... lol

FLOOD WATCH
NATIONAL WEATHER SERVICE LAKE CHARLES LA
956 PM CDT WED OCT 28 2009

...HEAVY RAINFALL EXPECTED THURSDAY AND FRIDAY...

.SHOWERS WILL CONTINUE TO DEVELOP AND STREAM NORTHWARD ACROSS THE
REGION INTO THURSDAY AS SOUTHERLY WINDS CONTINUE TO STRENGTHEN...
INCREASING LOW-LEVEL MOISTURE. FURTHER ALOFT...PACIFIC MOISTURE
WILL STREAM OVER THE AREA ON THE SUBTROPICAL JET STREAM.

A FAVORABLE JET STREAM ALOFT...AHEAD OF A STRONG STORM SYSTEM
PASSING THROUGH THE ROCKIES...WILL BE IN PLACE ACROSS SOUTHEAST
TEXAS BY THURSDAY EVENING...JUST IN TIME FOR THE ARRIVAL OF A
STRONG COLD FRONT. LIFT ASSOCIATED WITH THIS JET WILL SLOWLY PUSH
EAST ACROSS SOUTHWEST LOUISIANA INTO FRIDAY.

THE SLOW MOVING COLD FRONT WILL ADVANCE EAST ACROSS THE WESTERN
UPPER GULF COAST STATES ON FRIDAY...EXITING INTO SOUTHEAST
LOUISIANA BY FRIDAY EVENING.

THE RAIN WILL NOT END WITH THE PASSAGE OF THE FRONT...AS THE STRONG
LIFT ASSOCIATED WITH THE JET STREAM WILL MAINTAIN THE RAIN SHIELD
IN THE COOL POST-FRONTAL AIR. THIS COULD LEAD TO THE FLASH FLOOD
WATCH BEING REPLACED BY A FLOOD WATCH ON FRIDAY.

THE RAIN WILL BE COME TO AN END FROM WEST TO EAST ON SATURDAY AS
JET DYNAMICS AND ITS ASSOCIATED LIFT MOVES EASTWARD.

LAZ027-028-030-031-041-042-051-TXZ180>182-201-215-216-291100-
/O.CON.KLCH.FF.A.0003.091029T1200Z-091031T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
VERNON-RAPIDES-BEAUREGARD-ALLEN-CALCASIEU-JEFFERSON DAVIS-CAMERON-
TYLER-JASPER-NEWTON-HARDIN-JEFFERSON-ORANGE-
INCLUDING THE CITIES OF...LEESVILLE...ALEXANDRIA...DERIDDER...
OAKDALE...LAKE CHARLES...JENNINGS...CAMERON...WOODVILLE...
JASPER...NEWTON...LUMBERTON...BEAUMONT/PORT ARTHUR...ORANGE
956 PM CDT WED OCT 28 2009

...FLASH FLOOD WATCH REMAINS IN EFFECT FROM 7 AM CDT THURSDAY
THROUGH FRIDAY EVENING...

THE FLASH FLOOD WATCH CONTINUES FOR

* PORTIONS OF LOUISIANA AND SOUTHEAST TEXAS...INCLUDING THE
FOLLOWING AREAS...IN LOUISIANA...ALLEN...BEAUREGARD...
CALCASIEU...CAMERON...JEFFERSON DAVIS...RAPIDES AND VERNON. IN
SOUTHEAST TEXAS...HARDIN...JASPER...JEFFERSON...NEWTON...
ORANGE AND TYLER.

* FROM 7 AM CDT THURSDAY THROUGH FRIDAY EVENING

* THE COMBINATION OF A FAVORABLE JET STREAM...AN ADVANCING COLD FRONT...
AND DEEP GULF AND PACIFIC MOISTURE WILL LEAD TO WIDESPREAD RAINS
AND SOME THUNDERSTORMS BEGINNING THURSDAY.

* MEAN AREAL RAINFALL AMOUNTS AROUND 5 INCHES ARE POSSIBLE OVER
SOUTHEAST TEXAS. MEAN AMOUNTS AROUND 3 INCHES ARE POSSIBLE OVER
SOUTHWEST LOUISIANA. WITH NEARLY SATURATED SOILS FROM PREVIOUS RAINS...
RAPID SURFACE RUNOFF IS EXPECTED.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD
TO FLASH FLOODING. FLASH FLOODING IS A VERY DANGEROUS SITUATION.

PERSONS LIVING IN FLOOD PRONE AREAS SHOULD TAKE NECESSARY ACTIONS
TO PROTECT LIFE AND PROPERTY.

YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION
SHOULD FLASH FLOOD WARNINGS BE ISSUED.

Lake Wind Advisory

URGENT - WEATHER MESSAGE
NATIONAL WEATHER SERVICE LAKE CHARLES LA
959 PM CDT WED OCT 28 2009

...STRONG SOUTHERLY WINDS EXPECTED ON THURSDAY...

.THE COMBINATION OF THE HIGH PRESSURE TO OUR EAST AND LOW PRESSURE
OVER WEST TEXAS WILL LEAD TO STRONG SOUTHERLY WINDS OVER PORTIONS
OF THE AREA ON THURSDAY.

LAZ041>045-051>055-TXZ215-216-291100-
/O.CON.KLCH.LW.Y.0029.091029T1500Z-091029T2100Z/
CALCASIEU-JEFFERSON DAVIS-ACADIA-LAFAYETTE-UPPER ST. MARTIN-
CAMERON-VERMILION-IBERIA-ST. MARY-LOWER ST. MARTIN-JEFFERSON-
ORANGE-
INCLUDING THE CITIES OF...LAKE CHARLES...JENNINGS...CROWLEY...
LAFAYETTE...ST. MARTINVILLE...CAMERON...ABBEVILLE...NEW IBERIA...
MORGAN CITY...BEAUMONT/PORT ARTHUR...ORANGE
959 PM CDT WED OCT 28 2009

...LAKE WIND ADVISORY REMAINS IN EFFECT FROM 10 AM TO 4 PM CDT
THURSDAY...

A LAKE WIND ADVISORY REMAINS IN EFFECT FROM 10 AM TO 4 PM CDT
THURSDAY.

SUSTAINED SOUTHERLY WINDS AROUND 25 MPH WITH GUSTS TO NEAR 35 MPH
ARE POSSIBLE. HIGH PROFILE VEHICLES SHOULD EXERCISE CAUTION WHEN
TRAVELING ALONG EAST-WEST ROADS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A LAKE WIND ADVISORY INDICATES THAT WINDS WILL CAUSE ROUGH CHOP
ON AREA LAKES. SMALL BOATS WILL BE ESPECIALLY PRONE TO CAPSIZING.

[Jagno]

We are under flash flood watches and warnings as well as severe thunderstorm watch, wind advisory, coastal flooding and hazardous weather. They've also been announcing all day that sandbags are available at different locations throughout the parish. They've done extensive reporting of driving in flooded areas and the hazards of that alone in addition to remind people that the waves from the traffic causes some houses to flood that would have otherwise been okay. Apparently they feel that this is going to be bad because they generally don't get excited by anything. We just had 5.28" night before last which broke the record rainfall amounts by a landslide. Dangit, and all i wanted to do was find my umbrella. Now it looks like I'd best be looking for some hip weighters.

[southerngale]

EXCESSIVE RAINFALL DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
214 AM EDT THU OCT 29 2009

...VALID 06Z THU OCT 29 2009 - 12Z FRI OCT 30 2009...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
PSN INJ DUA BPK SAR M97 ACP 50 SE PSX NGP PSN.

MODERATE RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE
FROM
RUE ARG LLQ BPT PSX GGG RUE.

TOTAL RAINFALL AMOUNTS OF FIVE INCHES WILL BE POSSIBLE TO THE
RIGHT OF A LINE FROM LFK M89 IER BYY LFK.


...ERN TX/NWRN LA THRU ARK INTO SERN MO...
LRG SCALE MIDLVL TROF OVR THE WRN U.S. WL SLOLY MOV EWD WITH MDLS
CONTG TO SHOW A SOME SPLIT FLOW. ANOMALOUS 5H CLSD LOW OVR THE
4-CORNERS REGION CONTS TO DIG SWD AS ADDTNL SHRTWV ENERGY/UPR JET
STREAKS DIG INTO THE BACK OF THE SYS. EVENTUALLY IT WL BEGIN TO
WRK EWD WITH INCRSG DEEP LYRD CVRG THAT WL SUPPORT AN INTENSE LN
OF CNVCTN WITH CELLS LIFTG QUICKLY NWD...WHILE THE WHOLE LN MOVES
SLOLY EWD. INCRSG DEEP LYRD SRLY FLOW IS TAPPING DEEP GULF
MSTR...WITH EPAC MSTR ALSO GETTING DRAWN NEWD. PWS ARE FCST TO
INCRS THRU THE REGION WITH A RIBBON OF 1.50-2.25 INCH VALUES.
THESE ARE WELL ABV SEASONAL NRMLS AND 3-4 STDS ABV NRML. THIS
COMBINED WITH THE STG LLJ IS SUPPORTG 8H MSTR FLUX ANOMALIES OF
4-6 STDS ABV NRML. XPCT LESS ORGANIZED CNVCTN TDA THRU THE
REGION...WITH MORE ORGANIZED CNVCTN TNGT AS THE CDFNT PUSHES TWD
THE REGION. RNFL RATES OF 1-2 INCHES PER HR WL BE COMMON WITH
LCLLY HVIER TOTALS AS CELLS TRAIN ALMOST DUE N. SOME TOTALS BY FRI
MRNG IN EXCESS OF FIVE INCHES ARE PSBL.

ECKERT

[southerngale]

Also, SPC has our entire area in a Slight Risk.

Click here for tornado, hail, and wind maps as well.

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1256 AM CDT THU OCT 29 2009

VALID 291200Z - 301200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF THE SRN AND CNTRL
PLAINS INTO THE LOWER MS VALLEY...

...SYNOPSIS...

POSITIVE TILT UPPER TROUGH OVER THE SWRN STATES WILL ADVANCE SLOWLY
EAST THIS PERIOD WHILE A SERIES OF IMPULSES MOVE THROUGH THIS
FEATURE. LEAD IMPULSE CURRENTLY OVER THE SRN AND CNTRL HIGH PLAINS
WILL LIFT NWD THROUGH THE NRN PLAINS EARLY THURSDAY. A STRONGER
UPPER JET NOW ROUNDING THE BASE OF THE TROUGH WILL EJECT NEWD
THROUGH THE SRN PLAINS THIS AFTERNOON...REACHING THE CNTRL PLAINS BY
EARLY EVENING. AT THE SURFACE A WARM FRONT WILL LIFT NWD ACROSS NERN
TX...SERN OK AND THE LOWER MS VALLEY. A SURFACE LOW WILL DEVELOP
NEWD ALONG THE FRONT IN ASSOCIATION WITH EJECTING UPPER JET. THIS
FEATURE WILL REACH THE UPPER MS VALLEY LATE THURSDAY NIGHT. THE
TRAILING COLD FRONT WILL ADVANCE SLOWLY EWD THROUGH THE CNTRL AND
SRN PLAINS TODAY AND MID-LOWER MS VALLEY OVERNIGHT.

...SRN PLAINS THROUGH SERN KS...SWRN MO AND LOWER MS VALLEY...

RICH GULF MOISTURE WITH LOW 60S DEWPOINTS AS FAR NORTH AS ERN OK AND
LOW 70S ACROSS ERN TX AND THE LOWER MS VALLEY WILL ADVECT NWD IN
WAKE OF RETREATING WARM FRONT ALONG STRONG LOW LEVEL JET. MODEST MID
LEVEL LAPSE RATES AND AREAS OF CLOUDS WILL LIKELY LIMIT MLCAPE TO
AOB 1500 J/KG ACROSS MUCH OF THE WARM SECTOR...BUT MLCAPE COULD
APPROACH 2000 J/KG WHERE LOW CLOUDS CAN MIX OUT.

SCATTERED THUNDERSTORMS...MOST OF WHICH SHOULD BE AT LEAST SLIGHTLY
ELEVATED...MAY BE ONGOING EARLY THURSDAY MAINLY FROM NERN TX...ERN
OK INTO THE LOWER MS VALLEY WITHIN ZONE OF STRONGER ISENTROPIC LIFT
NORTH OF RETREATING WARM FRONT. UPPER FLOW WILL REMAIN MERIDIONAL
EAST OF UPPER TROUGH AND MAY RESULT IN AT LEAST SLIGHT WARMING IN
THE 850-500 MB LAYER ACROSS WARM SECTOR. THIS AND TENDENCY FOR
DEEPER FORCING ASSOCIATED WITH EJECTING UPPER JET TO REMAIN POST
FRONTAL RAISES CONCERNS THAT THE THERMODYNAMIC ENVIRONMENT COULD
POTENTIALLY LIMIT THE ROBUSTNESS AND EXTENT OF SURFACE BASED
THUNDERSTORMS IN WARM SECTOR. HOWEVER...VERTICAL SHEAR AND 0-1 KM
HODOGRAPHS WILL REMAIN SUFFICIENT FOR A THREAT OF SUPERCELLS AND
ISOLATED TORNADOES WITH ANY SURFACE BASED STORMS THAT DEVELOP.

OTHER STORMS WILL LIKELY CONTINUE WITHIN CORRIDOR OF DEEP ASCENT
ALONG BAROCLINIC ZONE AS IT ADVANCES EAST THROUGH TX...OK AND ERN KS
DURING THE DAY. THE NATURE OF THE FORCING AND MERIDIONAL UPPER FLOW
WILL PROMOTE PRIMARILY LINEAR STRUCTURES. HOWEVER...STORMS WILL
REMAIN WITHIN AN ENVIRONMENT CHARACTERIZED BY 50+ KT BULK SHEAR AND
SUFFICIENTLY LARGE LOW LEVEL HODOGRAPHS FOR EMBEDDED SUPERCELLS AND
BOWING SEGMENTS. DAMAGING WIND WILL BE THE MAIN THREAT WITH THIS
ACTIVITY...BUT ISOLATED TORNADOES WILL ALSO BE POSSIBLE. THREAT FOR
ISOLATED DAMAGING WIND MAY EXTEND AS FAR NORTH AS SERN KS AND SRN
MO...BUT NWD EXTENT OF THREAT WILL BE LIMITED BY WEAK INSTABILITY.

..DIAL/GARNER.. 10/29/2009