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New Orleans Local Weather thread - ROLLTIDE - 09-16-2009 03:53 AM

XUS64 KLIX 160846
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
346 AM CDT WED SEP 16 2009


.SHORT TERM...NOT MUCH CONVECTION DURING THE HEART OF THE DAY
YESTERDAY AND THIS WASN`T MUCH OF A SURPRISE OVER MOST OF THE AREA
THANKS TO THE INFLUX OF DRY AIR ALTHOUGH I DID THINK THERE MAY
HAVE BEEN SLIGHTLY BETTER COVERAGE ACROSS THE NW WHERE THE BEST
MOISTURE WAS LOCATED. OUR UPPER LOW IS STILL SPINNING OVER THE
ARKLATEX WHILE OUR BROAD SFC IS BASICALLY CENTERED OVER NE LA.
ANOTHER UPPER LOW WAS OVER THE FOUR CORNERS WHILE A STRONG S/W IS
DROPPING THROUGH THE GRT LAKES.

THROUGH THE FIRST FEW HRS THIS MORNING SHRA AND TSRA WILL BE SCT
TO NUM ACROSS THE MARINE ZONES ESPECIALLY EAST OF THE MOUTH OF THE
MS. THERE IS WEAK IMPULSE ALONG WITH A WEAK LL JET MOVING INTO THE
N-CNTRL GULF AND THIS APPEARS TO BE WHAT THIS ACTIVITY IS ASSOCIATED
WITH. THIS FEATURE SHOULD PULL OUT TO THE NE WITH CONVECTION COMING
TO AN END A FEW HRS AFTER SUNRISE.

TODAY...NOT EXPECTING A GREAT DEAL OF RAIN AGAIN. RATHER DRY
MID/UPPER LEVEL AIRMASS WILL REMAIN IN PLACE AND THIS HAS REALLY
HURT CONVECTIVE CHANCES THE LAST FEW DAYS. IN ADDITION WE REALLY
WON`T BE IN A FAVORABLE POSITION TO THE WEAK SUBTROPICAL JET. EVEN
WITH THE APPROACH OF ANOTHER DISTURBANCE THE LACK OF DEEP
MOISTURE(PWS AOB 1.8" AND K INDICIES IN THE MID TO LOWER 20S) AND
JET POSITION SHOULD KEEP MOST OF THE AREA AT BAY. THAT SAID ISLTD TO
SCT CONVECTION SHOULD STILL DEVELOP. THE SRN HALF OF THE CWA WILL
AGAIN SEE THE LEAST AMOUNT OF COVERAGE WITH THE BEST RAIN CHANCES
ACROSS THE NW MAINLY THIS AFTN. THE LACK OF DEEP MOISTURE WILL LEAD
TO LOWER INSTABILITY AND THIS SHOULD HURT ANY CHANCES OF SEEING
STRONG/SVR STORMS BUT I WON`T RULE OUT A FEW STRONG AND MAYBE A
ROGUE MARGINALLY SVR STORM...MAINLY ACROSS THE NORTH. CONVECTION
WILL AGAIN WIND DOWN AS WE HEAD INTO THE EVN HRS.

TOMORROW SHOULD BRING BETTER COVERAGE OF SHRA AND TSRA. OUR UPPER
LOW WILL ACTUALLY WORK SOUTH AND THIS WILL SEND A MUCH STRONGER
IMPULSE INTO THE CWA. THIS SHOWS UP VERY WELL IN THE GFS TROP FIELD
ALONG WITH PVU`S OF 3 AT H3 WORKING INTO THE CWA EARLY TOMORROW
AFTN. MOISTURE WILL ALSO INCREASE ACROSS THE REGION WITH PWS
APPROACHING 2" ONCE AGAIN. WITH INCREASING MOISTURE AND THIS MORE
SIGNIFICANT S/W NUM TO POSSIBLY WIDESPREAD CONVECTION SHOULD
DEVELOP. INSTABILITY WILL BE SOMEWHAT LACKING SO I WILL MAINLY WORD
THE GRIDS AND ZFP WITH SHRA AND EMBEDDED TSRA. ALSO WITH THE LACK OF
INSTABILITY STRONG TO SVR STORMS WILL BE HARD TO DEVELOP BUT
CONVECTION OVER THE MARINE ZONES WILL HAVE THE CAPABILITY OF
PRODUCING WATERSPOUTS. /CAB/

.LONG TERM...THE MDLS ARE HAVING SOME DIFFICULTY WITH THE EVOLUTION
OF THE UPPER LOW OVER OUR AREA. LUCKILY BOTH THE GFS AND ECMWF END
UP WITH A VERY SIMILAR PATTERN ENTERING NEXT WEEK. THROUGH THE FIRST
HALF OF NEXT WEEK THE GFS AND ECMWF AGREE WITH A DEEP ERN CONUS
TROUGH DEVELOPING THERE IS JUST SOME MINOR TIMING AND POSITION
DIFFERENCES BUT OVERALL NOT TOO FAR OFF FROM EACH OTHER. CONFIDENCE
IS STILL NOT THE GREATEST BUT IT IS STARTING TO LOOK LIKELY THAT A
RATHER DEEP TROUGH WILL DEVELOP EARLY NEXT WEEK AND SEND A FEW COLD
FRONTS DOWN THIS WAY WITH ONE POSSIBLY SIGNIFICANT AROUND THE MIDDLE
OF THE WEEK.

FRIDAY AND INTO THE WEEKEND...OUR UPPER LOW WILL FINALLY BE ON THE
MOVE THE QUESTION IS WHERE TO. THE S/W THAT IS CURRENTLY DIVING
SOUTH THROUGH THE GREAT LAKES COULD BEGIN TO INFLUENCE OUR UPPER LOW
LATE FRIDAY OPENING IT UP AND THUS KICKING IT OFF TO THE NORTHEAST.
NOW IF OUR UPPER LOW IS A TAD TOO FAR WEST THEN THIS S/W WILL BY PASS
IT AND OUR UPPER LOW WILL RETROGRADE AND MERGE WITH THE FOUR CORNERS
UPPER LOW ACROSS THE SRN/CNTRL PLAINS. EITHER WAY THERE WILL BE A
WEAK UPPER LOW OVER THE SRN/CNTRL PLAINS KEEPING US A IN WSW FLOW
ALBEIT WEAK. AS FOR RAIN FRI SHOULD BE THE HIGHEST OF THE THREE DAYS
COVERAGE WISE WITH SAT AND SUN PULLING BACK TO 20-40%. TEMPS WILL
ALSO BE A TAD WARMER BACK IN THE UPPER 80S THIS WEEKEND.

HEADING INTO NEXT WEEK A STRONG S/W WILL DIVE SOUTH OUT OF WRN
CANADA. THE UPPER LOW OVER THE CNTRL PLAINS WILL MERGE WITH THE NRN
STREAM SYSTEM WITH A DEEP TROUGH DEVELOPING OVER THE ERN CONUS BY
TUE MORNING. THIS WILL TRY TO PUSH A WEAK FRONT INTO THE REGION
AROUND THE SAME TIME. SCT SHRA AND TSRA WILL BE POSSIBLE ON MON WITH
THIS FRONT BUT A FEW DAYS LATER A STRONGER MORE SIGNIFICANT FRONT IS
POSSIBLE. THIS SHOULD BRING IN MUCH DRIER AND COOLER AIR INTO THE
CWA. OF COURSE THIS IS ABOUT 7 DAYS AWAY SO WE SHALL WAIT AND SEE IF
THIS COME TO FRUITION BUT AT LEAST THE MDLS HAVE BEEN HINTING AT
THIS FOR A FEW DAYS NOW. /CAB/

&&

.AVIATION...
SHOULD CONTINUE TO SEE VORTICITY SPOKES DUE TO DENSITY FORCING MOVE
AROUND THE BROAD STACKED LOW OVER SOUTHERN ARK. BETWEEN THESE
VORTICITY LOBES...SOME WARMING AND CAPPING WILL OCCUR AND CONVECTION
WILL BE MORE ISOLATED. ONE OF THESE SPOKES IS CURRENTLY RESIDING
FROM NEAR HOUMA TO NEAR PASCAGOULA. ALONG AND AHEAD OF THIS FEATURE
TS ARE BREAKING OUT. BEHIND IT...VERY LITTLE TO NOT ACTIVITY. WILL
CONSTRUCT THE SHORT TERM OF THE 12Z TAF SET TO SHOW THIS. EXPECT
SOME MVFR CEILINGS AROUND DAYBREAK TODAY AT GPT...BTR AND MCB.
SCATTERED CONVECTION SHOULD MAINLY AFFECT MSY AND GPT TODAY. BUT
ANOTHER VORT LOBE IS MOVING EAST OVER THE CENTRAL PART OF THE STATE.
THIS MAY BE ABLE TO KICK A FEW TS CELLS OFF TODAY AS IT GETS HELP
FROM DAYTIME HEATING.

&&


New Orleans Local Weather thread - dkmac - 09-17-2009 04:40 AM

From N.O. NWS:

Quote:AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
433 AM CDT THU SEP 17 2009

.SHORT TERM...
DISTINCTIVE SURFACE TROUGH EXTENDING FROM SURFACE REFLECTION OF
UPPER LOW PRESSURE SYSTEM SITUATED OVER NORTHEAST TEXAS. THIS
TROUGH IS DEMARKED ON RADAR BY A LINE OF WEAK CONVECTION THAT
EXTENDS FROM THE UPPER ATCHAFALAYA BASIN TO MORGAN CITY AND INTO
THE WEST-CENTRAL GULF OF MEXICO. OTHER CONVECTIVE CLUSTERS LOOSELY
ORIENTED IN CYCLONIC BANDING FEATURES DOT THE LOWER PARISHES AND
COASTAL WATERS AND EXTENDS INTO THE MISSISSIPPI COASTAL WATERS.
LARGE SCALE INSTABILITY IS MAINTAINED AND LOCALIZED FOCI SHOULD
ENHANCE RAIN CHANCES TODAY COMPARED TO PAST COUPLE OF DAYS. GFS
CONTINUES TO INDICATE THE UPPER LOW TO MEANDER OVER LOUISIANA FOR
ANOTHER DAY OR TWO. RAIN CHANCES SHOULD IMPROVE GRADUALLY AS THE
UPPER LOW FINALLY EJECTS OUT OF REGION. TEMPERATURES SHOULD REMAIN
NEAR NORMAL. 24/RR

.LONG TERM...
SHORT-TERM CUT-OFF LOW BECOMES REPLACED BY ANOTHER LOBE OF LOW
PRESSURE THAT DROPS OUT THE FRONT RANGE AND GETS CAUGHT PIECEMEAL
INTO HIGHER LATITUDE FLOW WHILE A PIECE BREAKS OFF AND BECOMES CUT
OFF IN THE ABSENCE OF A SOUTHERN BRANCH OVER TEXAS BY MIDDLE OF
NEXT WEEK. THIS SHOULD MAINTAIN GENERAL SOUTHWESTERLY FLOW ALOFT
WITH PERIPHERAL FLOW AROUND BERMUDA RIDGE NEAR THE SURFACE. A
PACIFIC TYPE FRONT APPROACHES THE FORECAST AREA BY MID-NEXT WEEK
BUT MAY STRUGGLE TO GET MUCH FARTHER EAST THAN THE ATCHAFALAYA
BASIN IF THE UPPER SYSTEM CUTS OFF AND STALLS OVER NORTH TEXAS AS
MODELS INDICATE. THIS SHOULD MEAN A PERIOD OF DAYS WITH ABOVE
NORMAL TEMEPERATURES AND NEAR NORMAL RAIN CHANCES MAINLY LIMITED
TO STEADY STATE SEA BREEZE CONVERGENCES. 24/RR

&&

.AVIATION...
SHOULD SEE MVFR TO IFR CIGS AND PATCHY FOG THROUGH DAYBREAK FOR MCB
AND NEAR GPT. ANY LOW CIGS AND FOG SHOULD LIFT SHORTLY AFTER SUNRISE
WITH DAYTIME HEATING. TWO MAIN VORTICTY LOBES MOVING AROUND THE
STACKED LOW OVER NE TX ARE SWINGING THROUGH LA THIS MORNING. THE
FIRST IS FOUND FROM VERMILION PARISH TO JUST WEST OF BTR. THIS
FEATURE WILL PROGRESS EAST TODAY BRINGING SH/TS TO THE BTR TERMINAL
THIS MORNING INTO THE NOON HOUR. THE SECOND IS LOCATED FROM GRAND
ISLE THROUGH THE LOWER PERL RIVER. AS THE MAIN CORE OF THE LOW
WABBLES EAST THESE LOBES WILL ALSO MOVE EAST BRINGING A GOOD CHANCE
OF SH/TS TO THE REMAINING TAF SITES...MCB MSY AND GPT. MAY TAKE SOME
HEATING TO HELP TRIGGER THINGS FARTHER FROM THE LOWS CORE. STRONGER
DYNAMIC FORCING CLOSER TO THE LOW SHOULD HELP TRIGGER TS TOWARD BTR
DURING THE MORNING HOURS. CAN`T FIND WHERE WIND SPEEDS ASSOCIATED
WITH ANY ONE TS WILL BE IN EXCESS OF 30KTS. 17/TE

&&

.MARINE...
MODELS CONTINUE TO INDICATE THAT WIND SPEEDS WILL BORDER ON CAUTION
CRITERIA FOR THE NEXT FEW DAYS AS A SURFACE LOW LINGERS NEAR THE
NORTHERN GULF COAST. WINDS EAST OF THE MISSISSIPPI RIVER HAVE BEEN
HOVERING RIGHT AROUND 15 KTS THIS MORNING. ISOLATED WATERSPOUTS WILL
CONTINUE TO BE POSSIBLE WITH SHOWERS AND THUNDERSTORMS DEVELOPING
OVER THE COASTAL WATERS THROUGH AT LEAST SAT. THE LOW SHOULD LIFT
OUT OF THE AREA AND WEAKEN FURTHER SUNDAY HELPING TO EASE WIND
SPEEDS AS THE PRESSURE GRADIENT RELAXES. A COLD FRONT WILL APPROACH
THE AREA TOWARD THE MIDDLE OF NEXT WEEK AND HEADLINES MAY BE
NECESSARY AT THAT TIME. 17/TE

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB 85 71 84 70 / 60 30 60 30
BTR 86 72 86 71 / 50 30 50 30
MSY 87 75 87 75 / 40 30 50 30
GPT 85 75 85 74 / 50 30 60 40



New Orleans Local Weather thread - ROLLTIDE - 09-17-2009 09:14 AM

00
FXUS64 KLIX 171343
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
843 AM CDT THU SEP 17 2009

.UPDATE...
...SOUNDING DISCUSSION...

NO PROBLEMS WITH THE FLIGHT THIS MORNING. THE SOUNDING LOOKS
SIMILAR TO YESTERDAY WITH PW PF 1.94 INCHES AND A GOOD AMOUNT OF
DRY AIR IN THE MID LEVELS BETWEEN 300 AND 500 MB. WITH A SIMILAR
SOUNDING YESTERDAY RAIN WAS HARD TO COME BY...SO A REPEAT OF THAT
CANNOT BE TOTALLY RULED OUT. WINDS REMAIN UNIDIRECTIONAL OUT OF
THE SOUTHWEST.

98/SO

&&

.PREV DISCUSSION... /ISSUED 433 AM CDT THU SEP 17 2009/

SHORT TERM...
DISTINCTIVE SURFACE TROUGH EXTENDING FROM SURFACE REFLECTION OF
UPPER LOW PRESSURE SYSTEM SITUATED OVER NORTHEAST TEXAS. THIS
TROUGH IS DEMARKED ON RADAR BY A LINE OF WEAK CONVECTION THAT
EXTENDS FROM THE UPPER ATCHAFALAYA BASIN TO MORGAN CITY AND INTO
THE WEST-CENTRAL GULF OF MEXICO. OTHER CONVECTIVE CLUSTERS LOOSELY
ORIENTED IN CYCLONIC BANDING FEATURES DOT THE LOWER PARISHES AND
COASTAL WATERS AND EXTENDS INTO THE MISSISSIPPI COASTAL WATERS.
LARGE SCALE INSTABILITY IS MAINTAINED AND LOCALIZED FOCI SHOULD
ENHANCE RAIN CHANCES TODAY COMPARED TO PAST COUPLE OF DAYS. GFS
CONTINUES TO INDICATE THE UPPER LOW TO MEANDER OVER LOUISIANA FOR
ANOTHER DAY OR TWO. RAIN CHANCES SHOULD IMPROVE GRADUALLY AS THE
UPPER LOW FINALLY EJECTS OUT OF REGION. TEMPERATURES SHOULD REMAIN
NEAR NORMAL. 24/RR

LONG TERM...
SHORT-TERM CUT-OFF LOW BECOMES REPLACED BY ANOTHER LOBE OF LOW
PRESSURE THAT DROPS OUT THE FRONT RANGE AND GETS CAUGHT PIECEMEAL
INTO HIGHER LATITUDE FLOW WHILE A PIECE BREAKS OFF AND BECOMES CUT
OFF IN THE ABSENCE OF A SOUTHERN BRANCH OVER TEXAS BY MIDDLE OF
NEXT WEEK. THIS SHOULD MAINTAIN GENERAL SOUTHWESTERLY FLOW ALOFT
WITH PERIPHERAL FLOW AROUND BERMUDA RIDGE NEAR THE SURFACE. A
PACIFIC TYPE FRONT APPROACHES THE FORECAST AREA BY MID-NEXT WEEK
BUT MAY STRUGGLE TO GET MUCH FARTHER EAST THAN THE ATCHAFALAYA
BASIN IF THE UPPER SYSTEM CUTS OFF AND STALLS OVER NORTH TEXAS AS
MODELS INDICATE. THIS SHOULD MEAN A PERIOD OF DAYS WITH ABOVE
NORMAL TEMEPERATURES AND NEAR NORMAL RAIN CHANCES MAINLY LIMITED
TO STEADY STATE SEA BREEZE CONVERGENCES. 24/RR

AVIATION...
SHOULD SEE MVFR TO IFR CIGS AND PATCHY FOG THROUGH DAYBREAK FOR MCB
AND NEAR GPT. ANY LOW CIGS AND FOG SHOULD LIFT SHORTLY AFTER SUNRISE
WITH DAYTIME HEATING. TWO MAIN VORTICTY LOBES MOVING AROUND THE
STACKED LOW OVER NE TX ARE SWINGING THROUGH LA THIS MORNING. THE
FIRST IS FOUND FROM VERMILION PARISH TO JUST WEST OF BTR. THIS
FEATURE WILL PROGRESS EAST TODAY BRINGING SH/TS TO THE BTR TERMINAL
THIS MORNING INTO THE NOON HOUR. THE SECOND IS LOCATED FROM GRAND
ISLE THROUGH THE LOWER PERL RIVER. AS THE MAIN CORE OF THE LOW
WABBLES EAST THESE LOBES WILL ALSO MOVE EAST BRINGING A GOOD CHANCE
OF SH/TS TO THE REMAINING TAF SITES...MCB MSY AND GPT. MAY TAKE SOME
HEATING TO HELP TRIGGER THINGS FARTHER FROM THE LOWS CORE. STRONGER
DYNAMIC FORCING CLOSER TO THE LOW SHOULD HELP TRIGGER TS TOWARD BTR
DURING THE MORNING HOURS. CAN`T FIND WHERE WIND SPEEDS ASSOCIATED
WITH ANY ONE TS WILL BE IN EXCESS OF 30KTS. 17/TE

MARINE...
MODELS CONTINUE TO INDICATE THAT WIND SPEEDS WILL BORDER ON CAUTION
CRITERIA FOR THE NEXT FEW DAYS AS A SURFACE LOW LINGERS NEAR THE
NORTHERN GULF COAST. WINDS EAST OF THE MISSISSIPPI RIVER HAVE BEEN
HOVERING RIGHT AROUND 15 KTS THIS MORNING. ISOLATED WATERSPOUTS WILL
CONTINUE TO BE POSSIBLE WITH SHOWERS AND THUNDERSTORMS DEVELOPING
OVER THE COASTAL WATERS THROUGH AT LEAST SAT. THE LOW SHOULD LIFT
OUT OF THE AREA AND WEAKEN FURTHER SUNDAY HELPING TO EASE WIND
SPEEDS AS THE PRESSURE GRADIENT RELAXES. A COLD FRONT WILL APPROACH
THE AREA TOWARD THE MIDDLE OF NEXT WEEK AND HEADLINES MAY BE
NECESSARY AT THAT TIME. 17/TE

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB 85 71 84 70 / 60 30 60 30
BTR 86 72 86 71 / 50 30 50 30
MSY 87 75 87 75 / 40 30 50 30
GPT 85 75 85 74 / 50 30 60 40

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&

$$


New Orleans Local Weather thread - dkmac - 09-18-2009 04:47 AM

From N.O. NWS:

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
406 AM CDT FRI SEP 18 2009

.SHORT TERM...
VERTICALLY STACKED OCCLUDED LOW PRESSURE SYSTEM THAT HAS BEEN IN
THE REGION FOR SEVERAL DAYS IS NOW SITUATED OVER NORTH LOUISIANA
WITH A SURFACE REFLECTION NEAR KIER /NATCHITOCHES LA/. A WEAK
TROUGH ARCHING FROM THE LOW ACROSS SOUTHWEST MISSISSIPPI...INTO
TERREBONNE PARISH AND CONTINUING OFFSHORE INTO THE WEST-CENTRAL
GULF OF MEXICO HAS BEEN SERVING AS A FOCUS FOR CONVECTION SINCE
LAST EVENING AND THROUGH THE NIGHT. RAINFALL RATES WERE RATHER
HIGH CLOSER TO MIDNIGHT BUT SINCE HAVE FALLEN TO MORE TYPICAL
LEVELS NEAR 1 INCH PER HOUR ACROSS TERREBONNE PARISH AND TAPERING
OFF AS ACTIVITY ADVANCES NORTHEAST TOWARDS THE NEW ORLEANS METRO
AREA. HAVE SOME CONCERNS WITH TRAINING BEHAVIOR THAT RADAR IS
DEPICTING AND SOME LOCALIZED FLOODING MAY BECOME AN ISSUE DURING
THE DAY. WILL INDICATE SUCH IN HAZARDOUS WEATHER OUTLOOK BUT WILL
NOT ISSUE ANY WATCH OR ADVISORY AT THIS TIME...THOUGH TRENDS WILL
BE CONTINUOUSLY MONITORED.

TODAY...THE LOW PRESSURE AREA AND ADDED LIFT WILL BE CLOSEST
TO THE FORECAST AREA THAN ANY TIME IN ITS SLOW MOVING EXISTENCE.
MOISTURE CONTENT REMAINS HIGH AND A LOW CONVECTIVE TEMPERATURE
WOULD POINT TO LIKELY CHANCES OF RAINFALL TODAY. WILL MAINTAIN THE
60-70 PERCENT RAIN CHANCES FOR DAYTIME AND 30-40 PERCENT FOR THIS
EVENING. JUDGING RAIN CHANCES FOR FRIDAY NIGHT PREP FOOTBALL
LOCATIONS WILL BE TOUGH BUT MOST LOCATIONS WILL PROBABLY BE DRY
AND OTHERS WILL BE DEALING WITH ANVIL DEBRIS LIGHT PRECIP THAT
SHOULD DISSIPATE AS THE EVENING WEARS ON. THE LOW PRESSURE AREA
SHOULD FILL AND EJECT OUT OF REGION DURING THE DAY SATURDAY WITH A
DIMINISHED CHANCE OF RAINFALL FOR SATURDAY. TEMPERATURES SHOULD
MANAGE TO GET CLOSE TO NEAR NORMAL LEVELS TODAY AND SATURDAY BUT
MAY BE DRAWN BACK UPON DOING SO DUE TO RAIN COOLING. 24/RR

.LONG TERM...
MODELS APPEAR TO BE IN BETTER AGREEMENT TONIGHT IN EVOLVING
ANOTHER LARGE CUT-OFF LOW ALOFT INTO THE MIDDLE OF THE COUNTRY
NEXT WEEK. THIS PATTERN WILL PRESENT A COLD FRONT OF SOME
SIGNIFICANCE ON APPROACH TOWARDS THE FORECAST AREA THAT MAY JUST
GET TEASINGLY CLOSE. THE ECMWF SHOWS THIS NEXT FEATURE TO PROGESS
SOUTHWARD TOWARDS OUR FORECAST AREA TOWARDS THE END OF NEXT WEEK
WHILE THE GFS BOTTOMS OUT OVER THE CENTRAL PLAINS BEFORE LIFTING
OUT WITH POLAR JET. BOTH SCENARIOS PLACE OUR AREA UNDER A MOIST
LONG FETCHED SOUTHWEST FLOW GRADIENT THAT COULD BRING ANOTHER
ROUND OF WETTER THAN NORMAL CONDITIONS TO THE REGION FOR NEXT
WEEK. AT THIS TIME...LEANING TOWARDS THE GFS AND KEEP POPS LOW
SUNDAY THROUGH TUESDAY BEFORE INCREASING RAIN CHANCES WEDNESDAY
THROUGH FRIDAY. 24/RR

&&

.AVIATION...
ISOLATED SHOWERS WILL CONTINUE TO MOVE NORTHEAST ACROSS THE REGION
AFFECTING THE BTR AND MSY TERMINALS THIS MORNING. THE BAND OF
SHOWER AND TSTMS FROM NEAR MSY EXTENDING OFFSHORE SHOULD CONTINUE TO
REMAIN IN TACT TODAY CAUSING PROBLEMS FOR MSY. EXPECTING ANOTHER
ROUND OF MVFR TO IFR CIGS THIS MORNING WITH IFR VSBYS DUE TO FOG
AT MCB NEAR DAYBREAK. CIGS AND VSBYS SHOULD RETURN TO VFR
CONDITIONS SHORTLY AFTER SUNRISE. EXCEPT IN THE VICINITY OF
THUNDERSTORMS...WINDS SHOULD REMAIN 10 KTS OR LESS. A BETTER
CHANCE OF SHOWERS AND TSTM ACTIVITY SHOULD BE EXPERIENCED BY ALL
TERMINALS WITH THE HIGHEST PROBS FOR MSY AND GPT. WILL MENTION
TSRA AND BKN030CB IN TEMPO GROUPS TODAY.

&&

.MARINE...
SURFACE LOW WILL CONTINUE TO LINGER NEAR THE NORTHERN GULF COAST
THROUGH SATURDAY...RESULTING IN ONSHORE FLOW AND A GOOD CHANCE OF
SEEING SHOWERS AND TSTMS. ISOLATED WATERSPOUTS WILL CONTINUE TO BE
POSSIBLE WITH SOME OF THE BETTER DEVELOPED ACTIVITY. THE LOW
SHOULD LIFT OUT OF THE AREA AND WEAKEN FURTHER SUNDAY...HELPING TO
EASE WIND SPEEDS AS THE PRESSURE GRADIENT RELAXES. FOR THE
MAJORITY OF THE COASTAL WATERS...EXPECT LIGHT WINDS AND SEAS OF 2
FEET OR LESS THROUGH MOST OF THE EXTENDED PERIOD. THE EXCEPTION
WILL BE THE MISS SOUND AREA. WINDS ARE EXPECTED TO CONTINUE IN THE
10 TO 15 KNOT RANGE TODAY AND SATURDAY. SOME STRENTHENING OF THESE
WINDS WILL OCCUR SATURDAY AND SATURDAY NIGHT. EXPECTING SUSTAINED
SPEEDS TO STAY AROUND 15KT WITH SOME GUSTS UP TO 20KT DURING THIS
TIME FRAME.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB 88 70 88 70 / 70 40 40 20
BTR 89 72 89 72 / 70 30 30 20
MSY 89 74 88 75 / 60 30 30 20
GPT 87 78 87 75 / 60 30 30 20


New Orleans Local Weather thread - ROLLTIDE - 09-18-2009 05:42 PM

000
FXUS64 KLIX 182025
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
325 PM CDT FRI SEP 18 2009

.SHORT TERM...
THE MID LEVEL CUT OFF LOW THAT HAS MEANDERED ACROSS TEXAS AND THE
LOWER MISSISSIPPI VALLEY FOR THE LAST SEVERAL DAYS...ALONG WITH ITS
SURFACE COUNTERPART...WILL SLOWLY BEGIN TO MOVE OFF TO THE
NORTHEAST OVER THE WEEKEND. AMPLE MOISTURE WILL...HOWEVER...
CONTINUE TO LINGER OVER THE REGION RESULTING IN A CONTINUATION OF
DAILY SCATTERED CONVECTION. HOWEVER...THE CONVECTIVE COVERAGE IS
EXPECTED TO DECREASE SOMEWHAT BY THE END OF THE WEEKEND AND THE
BEGINNING OF THE UPCOMING WORK WEEK. 11

.LONG TERM...
MODELS ARE IN FAIRLY GOOD AGREEMENT WITH THE NEXT MID/UPPER LEVEL
TROUGH THAT WILL MOVE INTO THE CENTRAL CONUS EARLY IN THE WEEK
WITH A LOW CLOSING OFF OVER THE CENTRAL PLAINS. THIS SYSTEM WILL
MOVE LITTLE FOR MUCH OF NEXT WEEK AS IT BECOMES CUT OFF FROM THE
WESTERLIES TO THE NORTH. A COLD FRONT IS FORECAST TO APPROACH THE
REGION BY TUESDAY...BUT WILL BE SLOW TO MOVE EAST AS THE UPPER
LEVEL SYSTEM REMAINS WELL TO THE WEST OVER THE PLAINS. WITH
SUFFICIENT MOISTURE IN PLACE...ABOVE NORMAL RAIN CHANCES ARE
EXPECTED FOR MUCH OF THE WEEK WITH THE FRONTAL BOUNDARY IN THE
REGION GRADUALLY WEAKENING. THE CLOSED LOW IS FORECAST TO BEGIN
MOVING TO THE EAST LATE IN THE WEEK AND NEXT WEEKEND...BUT MODEL
SOLUTIONS DIFFER IN THE TIMING AND EVOLUTION OF THIS SCENARIO.
SOME LOCALLY HEAVY RAINFALL AMOUNTS WILL BE POSSIBLE NEXT WEEK. 11

&&

.AVIATION...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO AFFECT
THE AREA THROUGH THIS EVENING BEFORE DIMINISHING TONIGHT. VFR
CONDITIONS ARE GENERALLY EXPECTED TO PREVAIL DURING DAYLIGHT
HOURS...BUT BRIEF PERIODS OF MVFR OR IFR CONDITIONS WILL BE POSSIBLE
WITH ANY CONVECTIVE ACTIVITY. AMPLE LOW LEVEL MOISTURE WILL ONCE
AGAIN LEAD TO THE DEVELOPMENT OF LOWER CIGS AND SOME PATCHY FOG
OVERNIGHT TONIGHT AND LASTING THROUGH THE EARLY MORNING HOURS. THE
THICKEST FOG IS EXPECTED NEAR MCB WHERE A COUPLE HOURS OF IFR
CONDITIONS WILL BE POSSIBLE. OTHERWISE...A RETURN TO VFR CONDITIONS
IS EXPECTED AFTER SUNRISE AS DAYTIME HEATING KICKS IN. 95/DM

&&

.MARINE...
THE STUBBORN SURFACE LOW THAT HAS BEEN PLANTED OVER THE NORTHERN
GULF COAST REGION WILL CONTINUE TO LINGER IN THE AREA THROUGH
SATURDAY...RESULTING IN ONSHORE FLOW AND A GOOD CHANCE OF SHOWERS
AND THUNDERSTORMS. ISOLATED WATERSPOUTS WILL CONTINUE TO BE POSSIBLE
WITH SOME OF THE BETTER DEVELOPED ACTIVITY. THE LOW IS STILL
EXPECTED TO LIFT OUT OF THE AREA BEGINNING SUNDAY. AS THE LOW MOVES
OUT OF THE AREA...THE PRESSURE GRADIENT WILL RELAX...RESULTING IN
LIGHT WINDS AND NEAR CALM SEAS ACROSS THE MAJORITY OF THE COASTAL
WATERS THROUGH THE EXTENDED PERIOD. 95/DM

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB 71 87 70 88 / 40 50 30 40
BTR 73 88 72 89 / 30 50 20 40
MSY 75 88 75 89 / 30 50 20 40
GPT 76 87 75 88 / 30 50 20 40

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.


New Orleans Local Weather thread - dkmac - 09-19-2009 05:59 AM

From N.O. NWS:

Quote:AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
336 AM CDT SAT SEP 19 2009

.SHORT TERM...
PESKY CUT-OFF LOW ALOFT APPEARS TO BE LIFTING OUT OF REGION NOW
LOCATED OVER THE MID-MISSISSIPPI VALLEY. A WEAK SURFACE REFLECTION
LOW AROUND 1013MB WAS ORPHANED OVER THE ATCHAFALAYA BASIN AND
SHOULD BECOME ABSORBED BY A NON-DESCRIPT PRESSURE GRADIENT AT THE
SURFACE. WITH A LACK OF FOCUS AND FAR LESS DYNAMICS ALOFT TODAY WILL
BACK RAIN CHANCES TO 30 PERCENT EXCEPT FOR 40-50 PERCENT IN
HARRISON AND JACKSON COUNTIES MISSISSIPPI WHERE A TROUGH AXIS
EXTENDS FROM THE UPPER LOW NEAR MEMPHIS TO ABOUT THE MOBILE BAY
AREA. THIS AREA HAS A BIT MORE FOCUS AND A RICHER MOISTURE POOL TO
HELP MAINTAIN SOMEWHAT BETTER CHANCES OF CONVECTION TODAY.
OTHERWISE...NEAR NORMAL TEMPERATURES TODAY AND SUNDAY WITH MAINLY
DAYTIME THUNDERSTORMS DIMINISHING TO ISOLATED EVENING COVERAGE OF
PREDOMINANTLY SHOWERS. 24/RR

.LONG TERM...
MODELS HAVE BEEN REALLY STRUGGLING WITH MAINTAINING ANY SENSE OF
RUN-TO-RUN CONSISTENCY WITH REGARDS TO NEXT CUT-OFF LOW EVOLUTION.
THE GFS NOW SHOWS A STRONG RETROGRESSION OF THE CUT-OFF LOW NOW
WEST OF THE CONTINENTAL DIVIDE AND STRONGER HIGH PRESSURE RIDGE
BUILDING OVER THE MIDDLE OF THE COUNTRY AND DEEP TROUGHING ALONG
THE EAST COAST. IF THIS SCENARIO PLAYS OUT THEN ANY SURFACE FRONT
WILL CERTAINLY STRUGGLE TO MAKE IT INTO AREA FROM THE WEST.
TELECONNECTIONS WOULD FAVOR A BETTER CHANCE OF A BACK DOOR FRONT
SETTLING INTO AREA FROM THE NORTHEAST IF EAST COAST TROUGH
CONTINUES TO AMPLIFY AS MODELS SUGGEST. THIS PATTERN IS ANOMALOUS
FOR MID SEPTEMBER SO CONFIDENCE IS NOT SO HIGH ON MODEL SOLUTIONS.
A GOOD COMPROMISE WOULD BE THE HOLD ONTO 30 PERCENT POPS EACH DAY
MAINLY DRIVEN BY GULF AND LAKE BREEZES AS CLIMATOLOGY WOULD
SUGGEST AND AWAIT BETTER MODEL CONSISTENCY BEFORE PLACING
CONFIDENCE ON ANY FRONTAL PASSAGES NEXT WEEK. TEMPERATURES SHOULD
BE NEAR TO A FEW DEGREES ABOVE NORMAL FOR THE WEEK. 24/RR

&&

.AVIATION...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL MAINLY AFFECT THE
EASTERN HALF OF THE AREA TODAY. VFR CONDITIONS ARE GENERALLY
EXPECTED TO PREVAIL DURING DAYLIGHT HOURS...BUT BRIEF PERIODS OF
MVFR OR IFR CONDITIONS WILL BE POSSIBLE WITH ANY CONVECTIVE
ACTIVITY. AMPLE LOW LEVEL MOISTURE WILL ONCE AGAIN LEAD TO THE
DEVELOPMENT OF LOWER CIGS AND SOME PATCHY FOG FOR A TIME DURING THE
EARLY MORNING HOURS. THE THICKEST FOG IS EXPECTED NEAR MCB WHERE A
COUPLE HOURS OF IFR CONDITIONS WILL BE POSSIBLE. OTHERWISE...A
RETURN TO VFR CONDITIONS IS EXPECTED AFTER SUNRISE. 17/TE

&&

.MARINE...
THE WEAK SURFACE LOW THAT HAS BEEN PLANTED OVER THE NORTHERN GULF
COAST REGION WILL FURTHER WEAKEN AND LIFT NORTHWARD TODAY. THIS
SHOULD KEEP MOST ACTIVITY OVER THE WATERS EAST OF THE MISS RIVER.
ISOLATED WATERSPOUTS WILL CONTINUE TO BE POSSIBLE WITH SOME OF THE
BETTER DEVELOPED ACTIVITY. LIGHT WINDS ~10KTS SHOULD CONTINUE
THROUGH MID WEEK. 17/TE

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB 87 70 87 70 / 30 20 30 20
BTR 89 72 89 72 / 30 10 30 20
MSY 89 75 89 75 / 30 10 30 20
GPT 89 75 88 75 / 40 20 30 20



New Orleans Local Weather thread - ROLLTIDE - 09-19-2009 02:30 PM

000
FXUS64 KLIX 191903
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
203 PM CDT SAT SEP 19 2009

.AVIATION...
ONLY ISOLATED SHOWERS ALONG THE MS COAST WERE BEING DETECTED BY
RADAR. OTHERWISE VFR CONDITIONS ARE THE RULE WITH SCT CLOUDS
AROUND 3 THOUSAND FEET AND UNRESTRICTED VISIBILITIES. LOW CLOUDS
SHOULD DISSIPATE AFTER DARK. OVERNIGHT...THERE IS A RISK OF
ISOLATED COASTAL SHOWERS. OTHERWISE LIGHT PATCHY FOG IS POSSIBLE
IN INTERIOR SECTIONS ESPECIALLY NEAR DAY BREAK HOWEVER...HEAVY DENSE
FOG COULD FORM NEAR KMCB OVERNIGHT AND PERIST UNTIL MID MORNING.

&&

.PREV DISCUSSION... /ISSUED 848 AM CDT SAT SEP 19 2009/

UPDATE...
SOUNDING DISCUSSION...

THE ATMOSPHERE REMAINS RELATIVELY MOIST MAINLY IN THE LOWER LEVELS
WHILE DRY AIR MOVES IN ALOFT...THE PRECIPITABLE WATER VALUE IS
1.95 INCHES. A LINE OF SHOWERS CONTINUE TO MOVE ACROSS THE
MISSISSIPPI GULF COAST THIS MORNING BUT NOT MUCH OTHER CONVECTION
ELSEWHERE. A SURFACE INVERSION IS PRESENT ALONG WITH LIGHT
SOUTHWEST WINDS UP TO 550 MB AND WESTERLY WINDS ALOFT.

PREV DISCUSSION... /ISSUED 336 AM CDT SAT SEP 19 2009/

SHORT TERM...
PESKY CUT-OFF LOW ALOFT APPEARS TO BE LIFTING OUT OF REGION NOW
LOCATED OVER THE MID-MISSISSIPPI VALLEY. A WEAK SURFACE REFLECTION
LOW AROUND 1013MB WAS ORPHANED OVER THE ATCHAFALAYA BASIN AND
SHOULD BECOME ABSORBED BY A NON-DESCRIPT PRESSURE GRADIENT AT THE
SURFACE. WITH A LACK OF FOCUS AND FAR LESS DYNAMICS ALOFT TODAY WILL
BACK RAIN CHANCES TO 30 PERCENT EXCEPT FOR 40-50 PERCENT IN
HARRISON AND JACKSON COUNTIES MISSISSIPPI WHERE A TROUGH AXIS
EXTENDS FROM THE UPPER LOW NEAR MEMPHIS TO ABOUT THE MOBILE BAY
AREA. THIS AREA HAS A BIT MORE FOCUS AND A RICHER MOISTURE POOL TO
HELP MAINTAIN SOMEWHAT BETTER CHANCES OF CONVECTION TODAY.
OTHERWISE...NEAR NORMAL TEMPERATURES TODAY AND SUNDAY WITH MAINLY
DAYTIME THUNDERSTORMS DIMINISHING TO ISOLATED EVENING COVERAGE OF
PREDOMINANTLY SHOWERS. 24/RR

LONG TERM...
MODELS HAVE BEEN REALLY STRUGGLING WITH MAINTAINING ANY SENSE OF
RUN-TO-RUN CONSISTENCY WITH REGARDS TO NEXT CUT-OFF LOW EVOLUTION.
THE GFS NOW SHOWS A STRONG RETROGRESSION OF THE CUT-OFF LOW NOW
WEST OF THE CONTINENTAL DIVIDE AND STRONGER HIGH PRESSURE RIDGE
BUILDING OVER THE MIDDLE OF THE COUNTRY AND DEEP TROUGHING ALONG
THE EAST COAST. IF THIS SCENARIO PLAYS OUT THEN ANY SURFACE FRONT
WILL CERTAINLY STRUGGLE TO MAKE IT INTO AREA FROM THE WEST.
TELECONNECTIONS WOULD FAVOR A BETTER CHANCE OF A BACK DOOR FRONT
SETTLING INTO AREA FROM THE NORTHEAST IF EAST COAST TROUGH
CONTINUES TO AMPLIFY AS MODELS SUGGEST. THIS PATTERN IS ANOMALOUS
FOR MID SEPTEMBER SO CONFIDENCE IS NOT SO HIGH ON MODEL SOLUTIONS.
A GOOD COMPROMISE WOULD BE THE HOLD ONTO 30 PERCENT POPS EACH DAY
MAINLY DRIVEN BY GULF AND LAKE BREEZES AS CLIMATOLOGY WOULD
SUGGEST AND AWAIT BETTER MODEL CONSISTENCY BEFORE PLACING
CONFIDENCE ON ANY FRONTAL PASSAGES NEXT WEEK. TEMPERATURES SHOULD
BE NEAR TO A FEW DEGREES ABOVE NORMAL FOR THE WEEK. 24/RR

AVIATION...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL MAINLY AFFECT THE
EASTERN HALF OF THE AREA TODAY. VFR CONDITIONS ARE GENERALLY
EXPECTED TO PREVAIL DURING DAYLIGHT HOURS...BUT BRIEF PERIODS OF
MVFR OR IFR CONDITIONS WILL BE POSSIBLE WITH ANY CONVECTIVE
ACTIVITY. AMPLE LOW LEVEL MOISTURE WILL ONCE AGAIN LEAD TO THE
DEVELOPMENT OF LOWER CIGS AND SOME PATCHY FOG FOR A TIME DURING THE
EARLY MORNING HOURS. THE THICKEST FOG IS EXPECTED NEAR MCB WHERE A
COUPLE HOURS OF IFR CONDITIONS WILL BE POSSIBLE. OTHERWISE...A
RETURN TO VFR CONDITIONS IS EXPECTED AFTER SUNRISE. 17/TE

MARINE...
THE WEAK SURFACE LOW THAT HAS BEEN PLANTED OVER THE NORTHERN GULF
COAST REGION WILL FURTHER WEAKEN AND LIFT NORTHWARD TODAY. THIS
SHOULD KEEP MOST ACTIVITY OVER THE WATERS EAST OF THE MISS RIVER.
ISOLATED WATERSPOUTS WILL CONTINUE TO BE POSSIBLE WITH SOME OF THE
BETTER DEVELOPED ACTIVITY. LIGHT WINDS ~10KTS SHOULD CONTINUE
THROUGH MID WEEK. 17/TE

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB 87 71 87 71 / 30 20 30 20
BTR 89 72 89 72 / 30 10 30 20
MSY 89 74 89 75 / 30 10 30 20
GPT 89 76 88 75 / 40 20 30 20

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.


New Orleans Local Weather thread - dkmac - 09-20-2009 05:24 AM

From N.O. NWS:

Quote:AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
416 AM CDT SUN SEP 20 2009

.SHORT TERM...
ANOTHER NIGHT OF LIGHT TROPICAL SHOWERS ALIGNED ON WEAK
CONVERGENCE FEATURES MAINLY EAST OF THE CHANDELEUR ISLANDS AND
STREAMING INTO JACKSON COUNTY AND POINTS EAST. ANOTHER BROKEN LINE
OF LIGHT SHOWERS EXTENDS ALONG A WEAK INVERTED TROUGH AXIS ACROSS
CENTRAL LOUISIANA. MUCH OF THE FORECAST AREA LIES IN A RELATIVE
DRY SLOT BETWEEN THESE TWO FEATURES. MODELS HAVE BEEN CONSISTENT
IN SHOWING HIGH RAIN CHANCES LATELY THAT HAVE NOT REALLY LIVED TO
BILLING AND TODAY APPEARS SIMILAR. ASIDE FROM WEAK TRANSITORY WIND
CONVERGENCE FEATURES THERE IS REALLY NO STRONG SYNOPTIC SCALE
LOW LEVEL FOCUS. MODEL SOUNDINGS LOOK RELATIVELY DRY AND NOT
SUPPORTIVE OF LARGE AREAS OF RAINFALL TODAY YET GFS AND NAM SHOW
AN OMEGA AND UPPER DIVERGENCE ABOVE 500 MB FEATURE MOVING THROUGH
THE AREA THIS AFTERNOON. HAVE OPTED TO UNDERCUT MODEL RAIN CHANCES TO
30 PERCENT FOR MUCH OF THE AREA TODAY EXCEPT A GRADIENT INTO 50
PERCENT ACROSS HARRISON AND JACKSON COUNTIES WHERE BETTER MOISTURE
CONVERGENCE IS PLACED MAINLY INTO THE MOBILE BAY AREA. A STREAM OF
DEEP LAYERED MOISTURE MOVING OUT OF MEXICO INTO EAST TEXAS SHOULD
REMAIN FOCUSED TO THE WEST AND NORTHWEST OF THE IMMEDIATE FORECAST
AREA.

MODELS CONTINUE TO STRUGGLE WITH RUN-TO-RUN AND CONSENSUS CONSISTENCY
IN HANDLING EVOLUTION OF UPPER LEVEL FLOW PATTERN...NAMELY IN
BREAKING A LARGE CUT-OFF LOW FROM THE NORTHERN BRANCH INTO THE MID
LATITUDES. THERE APPEARS TO BE MORE CONSENSUS TOWARDS A SURFACE
FRONT NOT PROGRESSING EAST OF THE ATCHAFALAYA BASIN IN THE
UPCOMING WEEK...AT LEAST NOT BY WEDNESDAY. WILL MAINTAIN A
FORECAST THAT IS CLOSER TO PERSISTENCE AND CLIMATOLOGY WHICH IS
LOWER DAILY RAIN CHANCES THAN NUMERICAL GUIDANCE IS REFLECTING BUT
STILL A CHANCE EACH DAY. 24/RR

.LONG TERM...
MUCH UNCERTAINTY WEDNESDAY AND BEYOND HIGHLY DEPENDENT ON EVENTUAL
EVOLUTION AND MEANDERINGS OF THE CUT-OFF LOW OVER THE CENTRAL
PLAINS. IF THE SYSTEM DOES LIFT IN TIME PER ECMWF...THEN A WEAK
SURFACE REFLECTION TROUGH MAY EVENTUALLY DRAG INTO THE FORECAST
AREA LATER IN THE WEEK. IF THE SYSTEM RETROGRADES WEST PER THE GFS
THEN PERSISTENT TROPICAL MARITIME AIRMASS REMAINS IN PLACE WITH
MESOSCALE GULF BREEZE BOUNDARIES BEING THE PRIMARY FOCUS FOR DAILY
RAIN CHANCES. WILL BE LEANING CLOSER TO THE PERSISTENCE SOLUTION
UNTIL SOME SIGNS OF HIGHER CONFIDENCE APPEAR IN THE NEXT COUPLE
OF DAYS MODEL RUNS. OF GROWING CONCERN WILL BE A SCENARIO WHEREBY
A WEAK BOUNDARY BECOMES QUASI-STATIONARY OVER THE FORECAST AREA IN
TIME TO GENERATE A HIGH RAINFALL...ECHO TRAINING AND FLOOD THREAT
IN THE WEDNESDAY TO FRIDAY TIME FRAME. THIS WILL HAVE TO BE
MONITORED IN COMING DAYS. 24/RR

&&

.AVIATION...
ANY CEILINGS SHOULD REMAIN AT BKN030 TODAY. PROBLEM AREAS WILL BE
THIS MORNING ON LOWERED CEILINGS AND VIS FOR A TIME AROUND SUNRISE.
MCB SHOULD BE THE WORST SITE GOING TO AROUND 1/4SM FOR AN HOUR OR
TWO AROUND SUNRISE. OTHER SITES WILL SEE SOME REDUCTION BUT SHOULD
REMAIN IN THE UPPER IFR AND MVFR CRITERIA. CONDITIONS WILL IMPROVE
TO VFR AT ALL LOCATIONS AFTER SUNRISE. SOME SHOWER ACTIVITY WILL BE
CLOSER TO MSY AND GPT TODAY AND TONIGHT AND MCB SHOULD FALL IN VIS
TO 1/2SM AGAIN LATE TONIGHT/EARLY MORNING.

&&

.MARINE...
AS THE UPPER LEVEL DISTURBANCE CONTINUES TO LIFT OUT INTO THE TN
VALLEY...A WEAK SURFACE TROUGH WAS LEFT BEHIND OVER LA AND MS. THIS
TROUGH SHOULD GRADUALLY WEAKEN AS BROAD HIGH PRESSURE SETTLES INTO
THE REGION BY EARLY NEXT WEEK.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB 86 71 85 71 / 30 20 30 20
BTR 89 74 88 73 / 30 20 30 20
MSY 89 76 89 76 / 30 20 30 20
GPT 88 77 88 77 / 30 20 30 20



New Orleans Local Weather thread - ROLLTIDE - 09-20-2009 04:23 PM

FXUS64 KLIX 202020
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
320 PM CDT SUN SEP 20 2009

.DISCUSSION...
ALTHOUGH THERE WAS A LITTLE MORE CONVECTIVE ACTIVITY TODAY THAN
YESTERDAY...THE RADAR WAS FAIRLY QUIET AGAIN TODAY. IT APPEARS
THAT SOME DRY AIR AND WARM TEMPERATURES IN THE MID LEVELS WERE ACTING
TO SUPPRESS DEVELOPMENT. MONDAY MAY BE A BIT MORE ACTIVE AS THE
FORECAST SOUNDINGS INDICATE AN INCREASINGLY MOIST ATMOSPHERIC PROFILE
WITH PRECIPITABLE WATERS VALUES APPROACHING TWO INCHES OR BETTER
ONCE AGAIN. HOWEVER...AS HAS BEEN THE CASE THE LAST FEW
DAYS...GUIDANCE POPS APPEAR SOMEWHAT GENEROUS. THE PLAN IS TO KEEP
POPS IN THE CHANCE CATEGORY MONDAY.

A BETTER CHANCE FOR CONVECTION APPEARS TO BE IN THE OFFING
BEGINNING ON TUESDAY. OVERALL...MODELS HAVE COME INTO BETTER
AGREEMENT WITH THE UPPER TROUGH THAT WILL DIG INTO THE PLAINS
EARLY IN THE PERIOD WITH A CUT OFF LOW DEVELOPING OVER THE CENTRAL
PLAINS. THERE ARE STILL SOME DIFFERENCES WITH THE EVOLUTION OF
THE FEATURE...BUT OVERALL THE MODELS ARE IN FAIRLY GOOD AGREEMENT
WITH THIS THROUGH MID WEEK. AS THIS OCCURS...A COLD FRONT IS
FORECAST TO APPROACH THE LOWER MISSISSIPPI VALLEY FROM THE WEST.
THIS BOUNDARY WILL MOST LIKELY STALL OUT WEST OF THE FORECAST AREA...
HOWEVER ITS PROXIMITY MAY ENHANCE CONVECTION CHANCES...ESPECIALLY
OVER WESTERN AND NORTHERN SECTIONS OF THE FORECAST AREA. AS A
RESULT... HIGH END CHANCE POPS WILL BE INCLUDED IN THE FORECAST
THROUGH THE MID AND EVEN INTO THE LATTER PART OF THE WORK WEEK AS
THIS BOUNDARY GRADUALLY WEAKENS SOMEWHERE IN THE VICINITY OF THE
LOWER MISSISSIPPI VALLEY.

THE CUT OFF LOW IN THE PLAINS IS FORECAST BY MOST MODELS TO MEANDER
OVER THE CENTRAL PLAINS OR THE FRONT RANGE REGION WITH THE GFS
STILL FORECASTING THE FEATURE TO RETROGRADE TO THE FOUR CORNERS
AREA. LATE IN THE FORECAST PERIOD...END OF THE WORK WEEK AND INTO
NEXT WEEKEND...THE MODELS OFFER VARIOUS SOLUTIONS WITH THIS CUT
OFF LOW OPENING UP AND BEING EJECTED TO THE EAST AND PUSHING A
COLD FRONT ACROSS THE LOWER MISSISSIPPI VALLEY AND CENTRAL GULF
COAST REGION. ALTHOUGH THERE IS STILL CONSIDERABLE UNCERTAINTY
WITH THE EVOLUTION AND TIMING OF THIS EJECTION AND THE PASSAGE OF
THE ASSOCIATED COLD FRONT...AT THIS TIME A FRONTAL PASSAGE WILL BE
SHOWN MOVING INTO THE AREA LATE IN THE WEEKEND. RAIN CHANCES WILL
BE MAINTAINED THROUGH THE WEEKEND TIME FRAME. 11

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL THROUGH EVENING. ISOLATED SHOWERS AND
TSTMS THRU 01UTC MAY PRODUCE IFR CONDITIONS FOR SHORT PERIODS OF
TIME. DURING OVERNIGHT HOURS MVFR VIS EXPECTED BETWEEN 10 AND 14UTC
AT MOST LOCATIONS WITH VIS IN 3 TO 5 MI RANGE. MCB AREA EXPECTED TO
EXPERIENCE SHORT PERIODS OF IFR OR LIFR CONDITIONS AGAIN AROUND
SUNRISE MON. VFR CONDITIONS FORECAST MONDAY WITH SLIGHT INCREASE IN
SHOWERS AND TSTM ACTIVITY. 21

&&

.MARINE...
WEAK GRADIENT SHOULD SUPPORTS LIGHT SE TO S FLOW INTO MONDAY. AS
LARGE UPPER LOW DEVELOPS OVER THE CENTRAL PLAINS IN THE TUE TO THU
TIME FRAME...ASSOCIATED FRONTAL BOUNDARY EXPECTED MOVE INTO WESTERN
AND CENTRAL LA...THEN STALL BY AS UPPER LOW REMAINS STATIONARY OR
RETROGRADES WESTWARD. SURFACE PRESSURE GRADIENT EXPECTED TO REMAIN
WEAK IN ADVANCE OF THE FRONT...SO WINDS LESS THAN 15 KNOTS EXPECTED.
COMBINATION OF FRONTAL BOUNDARY AND LOWER PRESSURES IN THE S GULF OF
WESTERN CARIBBEAN PROMOTES BACKING WINDS INTO MID WEEK...WITH WINDS
BECOMING LIGHT E TO NE OVER MARINE AREA IN THE MID TO LATE WEEK TIME
FRAME. 21

&&


.PRELIMINARY POINT TEMPS/POPS...
MCB 70 87 71 86 / 20 40 20 50
BTR 73 88 73 87 / 20 40 20 50
MSY 75 89 75 88 / 20 40 20 40
GPT 75 88 75 88 / 20 40 20 40

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
MS...NONE.
GM...NONE.
&&

$$

11/21


New Orleans Local Weather thread - dkmac - 09-21-2009 05:53 AM

From N.O. NWS:
Quote:AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
438 AM CDT MON SEP 21 2009

.SHORT TERM...
A BROAD MID/UPPER TROUGH COVERS THE NATIONS MID SECTION. WITHIN
THIS TROUGH...ONE MAJOR SHORTWAVE TROUGH IS MOVING NORTHEAST
ACROSS THE MID/UPPER MISSISSIPPI VALLEY WHILE ANOTHER
STRENGTHENING SYSTEM DROPS INTO THE NORTHERN/CENTRAL ROCKIES. THE
SUBTROPICAL JET STREAM EXTENDS FROM NORTHWEST MEXICO TO CENTRAL
TEXAS THEN INTO A VERY DIFFLUENT FLOW PATTERN OVER THE LOWER
MISSISSIPPI AND TENNESSEE VALLEY REGION. AN UPPER SHORTWAVE TROUGH
IS EMBEDDED IN THE JET OVER NORTHEAST TEXAS. WEAK PVA OVER THE
FORECAST AREA AND WEAK SEABREEZE AND LAKE BREEZE BOUNDARIES SHOULD
ASSIST IN THE DEVELOPMENT OF ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS TODAY. SEVERE THUNDERSTORMS ARE NOT EXPECTED.

TONIGHT AND TUESDAY...THE POTENT SHORTWAVE TROUGH OVER THE ROCKIES
EARLY TODAY WILL FORM INTO A CUT-OFF LOW OVER THE CENTRAL HIGH
PLAINS TONIGHT AND TUESDAY...THEN POSSIBLY RETROGRADE A BIT BACK
TO THE WEST TUESDAY NIGHT. THIS SYSTEM WILL DRIVE A COLD FRONT
THROUGH THE ARKLATEX REGION ON TUESDAY. THIS FRONT WILL THEN STALL
JUST NORTHWEST OF THE FORECAST AREA TUESDAY NIGHT. THE CHANCE OF
SHOWERS AND THUNDERSTORMS WILL INCREASE SLIGHTLY OVER ABOUT THE
NORTHWEST THIRD OF THE AREA ON TUESDAY WITH A CONTINUED CHANCE
ACROSS THE AREA TUESDAY NIGHT. THERE COULD BE A FEW STRONG TO
MARGINALLY SEVERE THUNDERSTORMS OVER THE FAR WESTERN PORTION OF
THE AREA NEAR THE ATCHAFALAYA RIVER TUESDAY AFTERNOON OR EVENING.

.LONG TERM...
HAVE FAVORED THE ECMWF OVER THE GFS MOST OF THE EXTENDED PERIODS.
THE MID/UPPER LOW WILL CIRCLE AROUND THE NEBRASKA/KANSAS/EASTERN
COLORADO REGION WEDNESDAY THROUGH FRIDAY BEFORE WEAKENING/OPENING
UP INTO A WAVE AND MOVING EAST ACROSS THE UPPER/MID MISSISSIPPI
VALLEY SATURDAY. AT THE SURFACE...THERE WILL BE BRIDGING OF
NORTHEAST THEN EAST WINDS OVER OUR AREA IN ADVANCE OF THE STALLED
FRONT TO OUR NORTH AND WEST WEDNESDAY THROUGH FRIDAY. THE BETTER
CHANCES OF SHOWERS AND THUNDERSTORMS WILL BE OVER THE NORTHWEST
HALF OF THE AREA WEDNESDAY THROUGH FRIDAY...THEN A WEAK COLD FRONT
SHOULD DRIVE MORE OF THE FOCUS FOR PRECIPITATION CLOSER TO THE
COAST OVER THE WEEKEND. SOME PERIODS OF HEAVIER RAIN COULD OCCUR
OVER PORTIONS OF SOUTHWEST MISSISSIPPI AND EAST CENTRAL
LOUISIANA...BUT THE HEAVIEST RAIN SHOULD REMAIN NORTHWEST/NORTH OF
THE AREA.

22/TD
&&

.AVIATION...
DURING MORNING HOURS MVFR VIS EXPECTED BETWEEN 10 AND 14UTC AT
MOST LOCATIONS WITH VIS IN 3 TO 5 MI RANGE. MCB AREA EXPECTED TO
EXPERIENCE SHORT PERIODS OF IFR OR LIFR CONDITIONS. VFR CONDITIONS
FORECAST TODAY WITH SLIGHT INCREASE IN SHOWERS AND TSTM ACTIVITY.
SOME LIGHT FOG CONDITIONS ONCE AGAIN TONIGHT WITH THE EXCEPTION OF
THOSE TERMINALS THAT FALL UNDER CEILINGS.

&&

.MARINE...
WEAK GRADIENT SHOULD SUPPORTS LIGHT SE TO S FLOW THROUGH TODAY. AS
LARGE UPPER LOW DEVELOPS OVER THE CENTRAL PLAINS IN THE TUE TO THU
TIME FRAME...ASSOCIATED FRONTAL BOUNDARY EXPECTED MOVE INTO WESTERN
AND CENTRAL LA...THEN STALL BY AS UPPER LOW REMAINS STATIONARY OR
RETROGRADES WESTWARD. SURFACE PRESSURE GRADIENT EXPECTED TO REMAIN
WEAK IN ADVANCE OF THE FRONT...SO WINDS LESS THAN 15 KNOTS EXPECTED.
COMBINATION OF FRONTAL BOUNDARY AND LOWER PRESSURES IN THE S GULF OF
WESTERN CARIBBEAN PROMOTES BACKING WINDS INTO MID WEEK...WITH WINDS
BECOMING LIGHT E TO NE OVER MARINE AREA IN THE MID TO LATE WEEK TIME
FRAME.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB 87 71 88 70 / 40 20 50 30
BTR 88 73 89 72 / 40 20 50 30
MSY 89 76 89 77 / 40 20 40 30
GPT 88 75 89 74 / 40 20 40 30