Hardcore Weather
New Orleans Local Weather thread - Printable Version

+- Hardcore Weather (http://hardcoreweather.com)
+-- Forum: Weather (/forum-4.html)
+--- Forum: Local Weather (/forum-13.html)
+--- Thread: New Orleans Local Weather thread (/thread-4989.html)



New Orleans Local Weather thread - ROLLTIDE - 05-05-2009 02:58 AM

Spotter Training - Baton Rouge/Slidell area LINKY:http://www.srh.noaa.gov/lix/html/SkyWrnpg.htm


New Orleans/Baton Rouge National Weather Service Office
--------------------------------------------------------------------------------

SKYWARN is a voluntary program developed by the National Weather Service where volunteers serve as storm spotters for the National Weather Service and local emergency management programs. Keeping their eyes on the sky, volunteers serve as the eyes and ears for the whole community. Storm spotters come from all walks of life but they all have generally two things in common - an interest in the weather and an interest in serving their community. The goal of SKYWARN is to improve the warning program by delivering timely severe weather warnings.

SKYWARN is a loosely knit organization. Training in severe storm identification comes from the National Weather Service. Often, another organization, such as emergency management, law enforcement, fire departments or rescue squads, or amateur radio groups, is the backbone of the SKYWARN effort in a particular community.



The National Weather Service needs real time reports of hail size, wind damage, flash flooding, heavy rain, and tornado development, in order to effectively warn the public. Even as new technology allows the National Weather Service to issue warnings with more lead time, spotters will always be needed as links between radar indications of severe weather and ground truth information.

If you are interested in becoming a Severe Storm Spotter and want to receive SkyWarn training, contact your local parish/county emergency management office or contact our Warning Coordination Meteorologist, at the National Weather Service Office in Slidell at 985-649-0357.


New Orleans Local Weather thread - dkmac - 05-05-2009 05:11 AM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
441 AM CDT TUE MAY 5 2009

.SHORT TERM...
FORECAST PROBLEMS ARE TIMING AND PLACEMENT OF FAST MOVING SYSTEMS
AND ASSOCIATED CHANCES OF SHOWERS AND THUNDERSTORMS IN A VERY
PROGRESSIVE PATTERN OVER THE NEXT COUPLE DAYS. SHORTWAVE TROUGHS
WILL MOVE IN FROM THE WEST-NORTHWEST...AND THE MODELS HAVE ALREADY
BEEN STRUGGLING FROM THE INITIAL PERIOD RESOLVING THE SHOWERS AND
THUNDERSTORMS THAT BROKE OUT LAST EVENING OVER THE I-20 CORRIDOR
OF NORTH LOUISIANA. THIS WEAKENING ACTIVITY IS CURRENTLY MOVING
EAST-SOUTHEAST ACROSS CENTRAL MISSISSIPPI AND SHOULD REMAIN MOSTLY
NORTH OF THE FORECAST AREA EARLY THIS MORNING. MID/UPPER LEVEL
SHORTWAVES/PERTURBATIONS WILL BE WEAK TODAY...SO THE MAIN FOCUS
SHOULD BE RESIDUAL SURFACE BOUNDARIES OVER THE AREA. THESE STILL
APPEARS TO BE A WEAK LEFTOVER WEST TO EAST SURFACE FRONT NEAR THE
I-12/10 CORRIDOR AND PERHAPS A WEAK OUTFLOW BOUNDARY THAT RECENTLY
PASSED THROUGH MCCOMB. INSTABILITY...SHEAR...AND MOISTURE WILL BE
ADEQUATE FOR SCATTERED THUNDERSTORMS TO DEVELOP BY LATE MORNING OR
AFTERNOON...A FEW OF WHICH COULD BRIEFLY APPROACH STRONG TO
SEVERE LIMITS.

ON WEDNESDAY...THE NAM BRINGS A SUBSTANTIAL SHORTWAVE TROUGH
THROUGH THE FORECAST AREA IN THE WEST-NORTHWEST FLOW ALOFT WHILE
THE GFS IS WEAKER AND FARTHER NORTH. BASED ON SPC/HPC
DISCUSSIONS...WILL USE A BLEND OF THE NAM AND GFS WITH POPS MORE
IN LINE WITH THE WETTER MET MOS GUIDANCE. SPC HAS A SLIGHT RISK OF
SEVERE THUNDERSTORMS OVER ABOUT THE NORTHWEST THIRD OF THE
FORECAST AREA WHICH FITS WELL WITH THE INSTABILITY AND SHEAR
FORECASTS. THERE MAY EVEN BE A FEW SEVERE STORMS AS FAR SOUTH AS
METRO NEW ORLEANS AND THE MISSISSIPPI GULF COAST.

.LONG TERM...
THE ADVERTISED VERY WARM/HOT AND DRY PATTERN LOOKS TO TAKE HOLD
THURSDAY INTO THE WEEKEND AND EARLY NEXT WEEK AS THE MID LEVEL
FLOW GRADUALLY BECOMES MORE WESTERLY TAKING SHORTWAVES WELL NORTH
OF THE FORECAST AREA. THE GFS TRIES TO PUSH A FRONTAL BOUNDARY
SOUTH TOWARDS THE NORTHERN BOUNDARY OF THE FORECAST AREA OVER THE
WEEKEND AND BRINGS 20 TO 30 PERCENT POPS TO THE AREA ON SUNDAY.
WILL NOT JUMP ON THIS SOLUTION YET SINCE THE 12Z MONDAY GFS AND
CURRENT 00Z ECMWF RUN SHOW THE FRONT FARTHER NORTH.

22/TD

&&

.AVIATION...
LOW CLOUDS HAVE BEEN EXPANDING ACROSS THE AREA WHICH HAS LIMITED THE
FOG DEVELOPMENT. VIS MAY STILL DROP TO MVFR BUT SHOULDN/T BE MUCH
WORSE. ALL SITES SHOULD BECOME VFR MID MORNING WITH MID LEVEL CU AND
HIGH CIRRUS DECKS DEVELOPING THIS AFTERNOON. SOUTH WINDS WILL REMAIN
LIGHT THROUGH THE DAY AT LESS THAN 10 KTS. RAIN CHANCES WILL
INCREASE THIS AFTERNOON...MAINLY AT MCB AND BTR.

MEFFER

&&

.MARINE...
LITTLE CHANGE EXPECTED FOR WIND INTENSITY TODAY. BOUNDARY STALLED
ACROSS LA WILL MOVE NORTHWARD TODAY AS HIGH PRESSURE BUILDS INTO THE
GULF. SEAS WILL REMAIN IN THE 2 TO 4 FOOT RANGE TODAY AND BASICALLY
FOR THE REST OF THE WEEK AND INTO THE WEEKEND AS THE CURRENT SURFACE
PATTERN PERSISTS. THE ONLY CONCERN DURING THIS PERIOD WILL BE
TONIGHT FOR THE POTENTIAL OF EXERCISE CAUTION CONDITIONS OVER THE
COASTAL WATERS WEST OF THE MS RIVER. AN AREA OF LOW PRESSURE WILL
DEVELOP ACROSS OK AND TRACK EASTWARD THROUGH AR. THIS WILL TIGHTEN
THE PRESSURE GRADIENT AND COULD RESULT IN 15 TO 20KT WINDS. WILL
NEED TO CONTINUE TO MONITOR.


New Orleans Local Weather thread - dkmac - 05-06-2009 04:35 AM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
458 AM CDT WED MAY 6 2009

.SHORT TERM...
WATER VAPOR IMAGERY...PROFILERS...AND RUC ANALYSIS SHOW A STRONG
250 MB JET THAT KEEPS PLOWING EAST-SOUTHEAST FROM THE CENTRAL
ROCKIES TO NORTH AND EAST TEXAS. TO THE NORTHEAST OF THIS
JETSTREAM IS A SHARP NEGATIVELY TILTED SHORTWAVE TROUGH THAT
EXTENDS FROM THE CENTRAL PLAINS INTO THE ARK-LA-TEX REGION. THE
MAIN HOT SPOT FOR STRONG CONVECTION HAS BEEN IN THE STRONGLY UPPER
DIVERGENT REGION FROM ARKANSAS TO PORTIONS OF THE TENNESSEE
VALLEY. SCATTERED SHOWERS AND A FEW THUNDERSTORMS HAVE BEEN MOVING
EAST ACROSS SOUTHEAST TEXAS WITH IR SATELLITE IMAGERY SHOWING
WARMING TOPS/GENERAL WEAKENING.

NONE OF THE MODELS HAVE A GREAT HANDLE ON THE QPF AT THE MOMENT
WHICH IS NO SURPRISE...BUT AM THINKING THE NAM MAY BE RESOLVING
THE CURRENT SCENARIO BETTER THAN THE GFS. WITH THAT IN MIND...WILL
KEEP THE PREVIOUS FORECAST POPS INTACT TODAY WHICH ARE 30 TO 40
PERCENT COMPARED TO THE GFS MAV 10 TO 20 PERCENT OUTPUT. THESE
HIGHER SHOWER AND THUNDERSTORM CHANCES ARE SUPPORTED BY STRONG PVA
AND AT LEAST A PERIOD OF UPPER DIVERGENCE ASSOCIATED WITH THE LEFT
EXIT REGION OF THE UPPER JET THAT WILL SLOWLY SHIFT EAST THROUGH
THE DAY. AS FAR AS SEVERITY...AM EXPECTING AT LEAST MODERATE
INSTABILITY DUE TO FAIRLY STRONG DAYTIME HEATING AND SURFACE
DEWPOINTS REMAINING UP NEAR 70. SHEAR WILL BE BEST THIS MORNING
THROUGH EARLY AFTERNOON OVER AREAS FROM BATON ROUGE TO MCCOMB AND
NORTHWEST. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER
SOUTHWEST/SOUTH CENTRAL MISSISSIPPI...BUT THERE WILL ALSO BE A
RISK OF A FEW SEVERE STORMS OVER SOME OF THE FLORIDA PARISHES AS
WELL. THE MAIN RISK WILL BE DAMAGING STRAIGHT LINE WINDS AND LARGE
HAIL WITH AN ISOLATED TORNADO POSSIBLE. STORMS WILL BE MOVING
PRETTY FAST...SO AM EXPECTING ANY HEAVY RAINFALL TO BE BRIEF.

THERE COULD BE SOME LEFTOVER...ISOLATED SHOWERS AND THUNDERSTORMS
THIS EVENING...AND POSSIBLY SOME ADDITIONAL ACTIVITY MOVING IN
OVERNIGHT FROM A SECONDARY IMPULSE IN THE WEST-NORTHWEST FLOW.

THURSDAY IS A LOW CONFIDENCE FORECAST AS FAR AS RAINFALL CHANCES.
THE 12Z MODEL RUNS FROM YESTERDAY PLAYED UP HIGHER POPS...BUT THE
00Z RUNS TODAY HAVE GONE BACK TO MOSTLY DRY. RATHER THAN FLIP-
FLOP...WILL HOLD ON TO SLIGHTLY HIGHER THAN GUIDANCE POPS SINCE
THERE COULD BE THE TAIL END OF ANOTHER WEAK DISTURBANCE IN THE
CONTINUED WEST-NORTHWEST FLOW ALOFT. MANY AREAS REMAIN QUITE
DRY...SO WILL NEED TO SEE SOME RAIN BEFORE A DRIER PATTERN SETS IN
DURING THE LONG TERM.

.LONG TERM...
A GENERALLY ZONAL FLOW PATTERN WILL TURN THE FLOW FROM WEST-
NORTHWEST TO MORE WESTERLY...SO THERE SHOULD NOT BE WORRIES ABOUT
ANYTHING COMING DOWN FROM THE NORTHWEST. THE MODELS ARE STILL
FAIRLY CONSISTENT SHOWING MID LEVEL HIGH PRESSURE OVER MEXICO AND
THE RIO GRANDE RIVER AREA BUILDING OVER THE WEEKEND AND SHIFTING
EAST TOWARDS THE GULF COAST DURING THE EARLY TO MID PART OF NEXT
WEEK. A STRONG SHORTWAVE TROUGH MOVING THROUGH THE UPPER
MISSISSIPPI VALLEY AND GREAT LAKES FOLLOWED BY WEAKER DISTURBANCES
OVER THE MID MISSISSIPPI AND OHIO VALLEYS FRIDAY NIGHT THROUGH
SUNDAY WILL CREATE BUILDING SURFACE HIGH PRESSURE WITH COOL AIR
THAT MAY PUSH A COLD FRONT DOWN INTO CENTRAL LOUISIANA AND SOUTH
MISSISSIPPI SATURDAY NIGHT INTO SUNDAY. HAVE BACKED OFF ON A DEEP
SOUTHWARD PUSH OF THIS FRONT AND ADJUSTED TEMPERATURES CLOSER TO
PERSISTENCE ON SUNDAY.

&&

.AVIATION...
RELATIVELY STRONG LLVL FLOW IS STREAMING ABUNDANT MOISTURE NORTHWARD
TOWARDS AREA OF LOW PRESSURE TO THE NORTH. ASSOCIATED LOW CLOUD HAS
DEVELOPED WITH CIGS IN THE MVFR RANGE. NO IMPROVEMENT IN CIGS
EXPECTED THROUGHOUT THE DAY. SHOWERS AND A FEW THUNDERSTORMS WILL BE
POSSIBLE TODAY AS A SHORTWAVE PROGRESSES EASTWARD OUT OF TEXAS
TOWARDS THE AREA. RAINFALL AMOUNTS SHOULD BE FAIRLY LIGHT AT LESS
THAN A TENTH OF AN INCH. CURRENT STEADY S TO SSW WINDS WILL INCREASE
TO 10 TO 15 KTS WITH GUSTS AROUND 20 KTS DURING THE DAY. OTHER THAN
WEAKENING WINDS AND SLIGHTLY LOWER POPS...NO CHANGE EXPECTED TONIGHT.

MEFFER
&&

.MARINE...
DEVELOPING SFC LOW OVER ARKANSAS IS RESULTING IN TIGHTENING OF THE
PRESSURE GRADIENT OVER THE AREA BETWEEN THAT FEATURE AND SURFACE
HIGH. WINDS HAVE BEEN BTW 15 AND 20 KTS IN THE COASTAL WATERS AND
SHOULD REMAIN THERE AT LEAST UNTIL NOON SO EXERCISE CAUTION WILL BE
IN EFFECT. THE QUESTION REMAINS FOR THE TIDAL LAKES. INITIAL
NOCTURNAL INCREASE TO OVER 15 KTS HAS RELAXED TO AROUND 10 KTS.
CONCERN IS THAT STRONGER WINDS SEEN AROUND 2KFT ON VWP WILL MIX DOWN
WITH THE LOSS OF THE INVERSION FROM DAYTIME HEATING. SO HAVE DECIDED
TO INCLUDE THE LAKES IN THE EXRCS CAUTION. THROUGH THE REST OF THE
WEEK AND INTO THE WEEKEND...STRONGER SFC RIDGE BUILD IN TO THE
EASTERN GULF. THUS...ONSHORE TO CONTINUE FOR THE REST OF THE PERIOD.
SERIES OF IMPULSE WILL PASS TO THE NORTH OF THE FORECAST AREA AND
SHOULD HAVE LITTLE IMPACT ON THE GULF WATERS.


New Orleans Local Weather thread - dkmac - 05-07-2009 04:46 AM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
456 AM CDT THU MAY 7 2009

.SHORT TERM...

SATELLITE IMAGERY SHOWS UPPER TROUGH WELL EAST OF OUR AREA MOVING
TOWARDS THE EASTERN SEABOARD. IN THE WAKE OF THIS TROUGH...A
SUBTLE 850-700 MB CONVERGENCE BOUNDARY WITH DEEPER MOISTURE
EXTENDS FROM THE NORTH HALF OF LOUISIANA ACROSS CENTRAL AND
SOUTHWEST MISSISSIPPI. WATER VAPOR IMAGERY STILL SHOWS A VERY
PROGRESSIVE PATTERN AND ANOTHER SHORTWAVE TROUGH EMERGING OVER THE
CENTRAL HIGH PLAINS AND TEXAS/OKLAHOMA PANHANDLE REGION. SOME OF
THIS ENERGY SHOULD MOVE EAST-SOUTHEAST ACROSS THE LOWER
MISSISSIPPI VALLEY LATER TODAY DURING PEAK HEATING. SOME OF THE
DEEPER MOISTURE TO OUR NORTH SHOULD MOVE INTO MORE OF THE
NORTH/NORTHWEST PORTION OF THE FORECAST AREA THIS AFTERNOON IN
BROADLY DIFFLUENT MID/UPPER LEVEL FLOW. ALTHOUGH THE MODELS HAVE
BEEN OVERDOING THE POPS/QPF THE LAST COUPLE DAYS...THERE SHOULD BE
SUFFICIENT COMBINATION OF FACTORS INCLUDING BETTER SURFACE HEATING
TODAY TO INCLUDE A BETTER CHANCE OF SHOWERS AND THUNDERSTORMS OVER
SOUTHWEST MISSISSIPPI AND BORDERING AREAS OF EAST CENTRAL/
SOUTHEAST LOUISIANA BY THIS AFTERNOON. THE NORTHERN PORTIONS OF
THIS AREA IS IN A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY. THE
MAIN THREAT APPEARS TO BE DAMAGING WINDS SINCE WARMER TEMPERATURES
ALOFT SHOULD LESSEN THE HAIL THREAT.

A MORE ZONAL...STRAIGHT WEST TO EAST...UPPER FLOW PATTERN IS
EXPECTED TO SHIT THE TRACK OF UPPER DISTURBANCES WELL NORTH OF OUR
AREA ON FRIDAY. THE OPPORTUNITY FOR EVEN SPOTTY RAIN SHUTS DOWN ON
FRIDAY AS DRIER AIR WORKS IN ABOVE THE SURFACE...SO EXPECT PLENTY
OF SUNSHINE AND VERY WARM TO HOT TEMPERATURES.

.LONG TERM...

THE ZONAL FLOW PATTERN FROM FRIDAY CONTINUES INTO THE WEEKEND WITH
WEATHER SYSTEMS AND RAINFALL REMAINING UP IN THE MID SOUTH REGION.
LOCAL WEATHER WILL REMAIN VERY WARM...MOSTLY SUNNY AND DRY. AN
APPROACHING FRONTAL BOUNDARY WILL BE SAGGING SLOWLY SOUTH INTO
NORTHERN LOUISIANA AND CENTRAL MISSISSIPPI.

THE MID LEVEL FLOW WILL AMPLIFY SLIGHTLY AGAIN LATE SUNDAY INTO
TUESDAY WITH A NORTHWEST FLOW COMPONENT EXPECTED OVER THE LOWER
MISSISSIPPI VALLEY INTO THE TENNESSEE VALLEY. THIS MAY CAUSE THE
SURFACE FRONT TO SAG OR BACK DOOR INTO THE FORECAST AREA MONDAY OR
MONDAY NIGHT. A POOLING OF HIGHER MOISTURE ALONG THE FRONT
COMBINED WITH INSTABILITY FROM DAYTIME HEATING...AND POSSIBLY A
WEAK DISTURBANCE OR TWO ALOFT SHOULD BRING A SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS BACK INTO THE PICTURE.

IT APPEARS A MID LEVEL RIDGE SHOULD BUILD OVER OR NEAR THE CENTRAL
GULF COAST REGION WEDNESDAY INTO LATE NEXT WEEK WHICH WOULD ARGUE
FOR A VERY WARM AND MOSTLY DRY FORECAST.

22/TD
&&

.AVIATION...
...PRELIMINARY 12Z AVIATION DISCUSSION...

A MIX OF MVFR AND VFR CONDITIONS WILL PERSIST THROUGH THE MORNING
HOURS. BKN015 WILL MAINLY OCCUR AT MCB AND BTR AND WILL GRADUALLY
LIFT THROUGH THE MORNING. SCT-BKN050 SHOULD BE MAINLY SEEN AT MSY
AND GPT. SOME LIGHT BR CONDITIONS MAY ALSO BE SEEN FOR A SHORT TIME
AROUND MCB. VCTS WILL ALSO OCCUR MAINLY DURING THE AFTERNOON FOR MCB
AND COULD IMPACT BTR. EXPECT ALL CONVECTION TO WEAKEN AND DECAY AT
SUNSET. FOG MAY BE MORE OF AN ISSUE TONIGHT WHERE RAIN OCCURS.

&&

.MARINE...
DEEP SOUTHERLY FLOW IN THE LOW LEVELS...ON THE WESTERN PERIPHERY OF
A SURFACE RIDGE PARKED OVER FLORIDA WILL REMAIN IN CONTROL THROUGH
THE WEEKEND AND INTO EARLY NEXT WEEK. A SLOW MOVING FRONT WILL MOVE
TOWARD THE GULF COAST TUESDAY. THE FRONT IS NOT EXPECTED TO MOVE
THROUGH THE COASTAL WATERS ATTM BUT MAY GET CLOSE ENOUGH TO PRODUCE
SOME SH/TS.


New Orleans Local Weather thread - dkmac - 05-08-2009 05:58 AM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
502 AM CDT FRI MAY 8 2009

.SHORT TERM...
DRY AND VERY WARM AIR WILL REINFORCE OVER THE AREA TODAY...AND
THIS DRYING IS ALREADY EVIDENT IN THE SURGE OF LOW PRECIPITABLE
WATER OBSERVED COMING IN FROM THE SOUTH. SOME OF THE DRY AIR HAS
ALSO WORKED DOWN TO THE SURFACE WITH DEWPOINTS DOWN A COUPLE
DEGREES FROM 24 HOURS AGO. THIS HAS ALLOWED TEMPERATURES TO FALL
INTO THE LOWER 70S OVER MOST OF THE AREA WHICH IS A LITTLE MORE
REASONABLE THAN THE UNSEASONABLY WARM MID 70S LOWS THE LAST COUPLE
MORNINGS. THIS RELATIVE COOLNESS WILL NOT LAST LONG ONCE LOW
CLOUDS BURN OFF THIS MORNING. HIGH TEMPERATURES SHOULD BE ABOUT A
DEGREE HIGHER THAN YESTERDAY WHICH MEANS MOST AREAS WILL SEE UPPER
80S TO AROUND 90. THE EXCEPTION WILL BE NEAR THE COAST WHERE 80
DEGREE WATER SHOULD HOLD HIGHS DOWN IN THE 80 TO 85 DEGREE RANGE.

A STRONG ZONAL FLOW PATTERN ACROSS THE MIDDLE SECTION OF THE CONUS
WITH A STRONG TEMPERATURE GRADIENT WILL BE ENHANCED TONIGHT AND
SATURDAY AS A STRONG SHORTWAVE TROUGH AND ASSOCIATED SURFACE LOW
MOVE ACROSS THE UPPER MISSISSIPPI VALLEY AND GREAT LAKES. THIS
WILL PUSH A EAST-NORTHEAST TO WEST-SOUTHWEST ORIENTED COLD FRONT
BACK SOUTH TOWARDS THE DEEP SOUTH...POSSIBLY REACHING CENTRAL
LOUISIANA AND INLAND SOUTH OR SOUTH CENTRAL MISSISSIPPI LATE
SATURDAY. THIS WILL AID IN COMPRESSIONAL HEATING WITH TEMPERATURES
CONTINUING TO WARM UNDER MOSTLY SUNNY SKIES.

.LONG TERM...
A CONTINUED TRAIN OF UPPER SHORTWAVES WILL START TO BUCKLE THE
JET WITH THE GFS SHOWING A DEEPENING TROUGH OVER THE NORTHEAST TO
MID ATLANTIC STATES MONDAY INTO TUESDAY. THE FRONTAL BOUNDARY WILL
LINGER JUST NORTH OF THE FORECAST AREA SUNDAY...THEN GET A PUSH
INTO OR POSSIBLY THROUGH THE FORECAST AREA MONDAY INTO TUESDAY.
THE ECMWF SHOWS A MUCH FLATTER UPPER PATTERN AND IS NOT AS
AGGRESSIVE WITH THE FRONT...SHOWING A MORE BACK DOOR SAGGING OF
THE FRONTAL BOUNDARY INTO THE AREA. WILL GO WITH A COMPROMISE
SOLUTION WHICH IS A BIT WARMER AND SLIGHTLY DRIER THAN THE MEX
GUIDANCE ON MONDAY THEN NEAR MEX POPS THE REMAINDER OF THE WEEK.
WILL HAVE A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS IN THE FAR
NORTH SUNDAY AND MOST OF THE AREA MAINLY DAYTIME MONDAY THROUGH
LATE NEXT WEEK. RIGHT NOW THE BEST CHANCE OF RAIN...ONLY 30
PERCENT...IS ON MONDAY. THE BIG MODEL CHANGE FROM A COUPLE DAYS
AGO IS THE ABSENCE OF A UPPER RIDGE/HIGH OVER OR NEAR THE GULF
COAST REGION LATER NEXT WEEK. IN FACT...A DEEP SHORTWAVE TROUGH
WILL BE MOVING ACROSS THE NORTHERN TIER OF STATES DURING THE
WEEK WITH SOME PHASING OR BREAKING OFF OF MID/UPPER TROUGHING
EXPECTED OVER THE GULF COAST REGION LATE IN THE WEEK. HAVE LOWERED
HIGH TEMPERATURES SLIGHTLY AND THEY MAY NEEDED TO BE LOWERED A
COUPLE DEGREES LATE IN THE WEEK IF MODEL TRENDS CONTINUE.

22/TD
&&

.AVIATION...
KLIX SOUNDING CONTINUES TO INDICATE MOISTURE MAINLY CONFINED TO THE
LOWEST FEW THOUSAND FEET. AS A RESULT...NIGHT TIME LOW LEVEL MVFR
CEILINGS ARE BEING WITNESSED AND DURING THE DAY ONLY SCATTERED TO
BROKEN CUMULUS BETWEEN 3K AND 4K FEET ARE BEING OBSERVED. WINDS
SHOULD CONTINUE TO BE LIGHT.

&&

.MARINE...
DEEP SOUTHERLY FLOW IN THE LOW LEVELS...ON THE WESTERN PERIPHERY OF
A SURFACE RIDGE PARKED OVER FLORIDA WILL REMAIN IN CONTROL THROUGH
THE WEEKEND AND INTO EARLY NEXT WEEK. A SLOW MOVING WEAK COLD FRONT
WILL MOVE TOWARD THE GULF COAST TUESDAY. THE FRONT IS NOT EXPECTED
TO MOVE THROUGH THE COASTAL WATERS BUT MAY GET CLOSE ENOUGH TO
PRODUCE SOME WIDELY SCATTERED SHOWERS OR THUNDERSTORMS.


New Orleans Local Weather thread - dkmac - 05-09-2009 05:00 AM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
411 AM CDT SAT MAY 9 2009

.SHORT TERM...
A NEARLY ZONAL FLOW PATTERN WILL PREVAIL ACROSS MOST OF THE CONUS
THROUGH THE WEEKEND WITH UPPER LEVEL RIDGING ACROSS THE GULF OF
MEXICO AND THE GULF COAST REGION PROVIDING FOR A CONTINUATION OF
THE STRING OF DAYS WITH ABOVE NORMAL TEMPERATURES. DRY WEATHER
WILL BE IN THE OFFING TODAY WITH SIGNIFICANT MOISTURE CONFINED TO
THE LOWEST LEVELS OF THE ATMOSPHERE. AN UPPER TROUGH MOVING FROM
THE UPPER MISSISSIPPI VALLEY AND ACROSS THE GREAT LAKES TODAY AND
TONIGHT WILL PUSH INTO NEW ENGLAND ON SUNDAY. THIS FEATURE WILL
PUSH A FRONTAL BOUNDARY SOUTH TO NEAR THE FORECAST AREA SUNDAY
INTO MONDAY. DURING THIS TIME FRAME...MOISTURE WILL INCREASE AND
DEEPEN ACROSS THE AREA WITH PRECIPITABLE WATER VALUES FORECAST TO
CLIMB INTO THE 1.5 TO 1.7 INCH RANGE. IN ADDITION...IT APPEARS
THAT A COUPLE OF WEAK SHORT WAVES WILL MOVE ACROSS THE LOWER
MISSISSIPPI VALLEY DURING THIS PERIOD. AS A RESULT...CHANCE POPS
ARE IN ORDER FOR SUNDAY AND MONDAY AND POSSIBLY EVEN TUESDAY. SPC
HAS OUTLOOKED SECTIONS OF THE FORECAST AREA FOR A SLIGHT RISK OF
SEVERE THUNDERSTORMS BOTH SUNDAY AND MONDAY AS THE AFOREMENTIONED
FRONTAL BOUNDARY SAGS SOUTH INTO THE AREA. THE RETURN OF
SUFFICIENT MOISTURE ALONG WITH CONSIDERABLE INSTABILITY EACH DAY
AS AFTERNOON HIGH TEMPERATURES CLIMB INTO THE MID AND UPPER 80S
INDICATE THAT AN ISOLATED THREAT OF STRONG TO SEVERE THUNDERSTORMS
WILL EXIST. 11


.LONG TERM...
ANOTHER FRONTAL BOUNDARY MAY PUSH INTO THE FORECAST AREA ON
THURSDAY AS AN UPPER LEVEL TROUGH TRACKS ACROSS THE NORTHERN TIER
OF STATES WITH CHANCE POPS ONCE AGAIN IN THE OFFING. IT A APPEARS
THAT THE RETURN OF UPPER LEVEL RIDGING FOR THE END OF NEXT WEEK
AND NEXT WEEKEND WILL LIMIT CONVECTION ONCE AGAIN. 11

&&

.AVIATION...
KLIX SOUNDING CONTINUES TO INDICATE MOISTURE MAINLY CONFINED TO THE
LOWEST FEW THOUSAND FEET. AS A RESULT...NIGHT TIME LOW LEVEL MVFR
CEILINGS ARE OCCURRING THIS MORNING WHILE DURING THE DAY ONLY
SCATTERED TO BROKEN CUMULUS BETWEEN 3K AND 4K FEET WILL BE OBSERVED.
SOME LIGHT FOG SHOULD DEVELOP AS WINDS CONTINUE TO WEAKEN THROUGH
SUNRISE AND SHOULD BE MORE PREVALENT AT MCB AND BTR. 17


&&

.MARINE...
STRONGER WINDS HAVE FORMED AGAIN THIS MORNING MAINLY BETWEEN THE
BARRIER ISLANDS AND MAINLAND. CAUTION HEADLINES WILL ONLY BE NEEDED
IN THE NEAR SHORE WATERS. A WEAK DISTURBANCE WILL MOVE AROUND THE
PERIPHERY OF THE HIGH TO THE EAST AND BRING DEEPER MOISTURE BACK TO
THE AREA THE DISTURBANCE ALONE WILL BE ENOUGH TO DEVELOP SOME SH/TS
OVER THE COASTAL WATERS SAT NIGHT INTO SUNDAY. A WEAK SLOWLY MOVING
TROUGH WILL STALL AND WEAKEN NEAR THE COAST MONDAY AND A FEW TS
COULD DEVELOP NEAR SHORE. LARGE SCALE RIDGING WILL COMMENCE ONCE
AGAIN OVER THE AREA FOR THE REMAINDER OF THE WEEK. 17


New Orleans Local Weather thread - dkmac - 05-10-2009 05:07 AM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
344 AM CDT SUN MAY 10 2009

.SHORT TERM...
WEAK TROUGH CONTINUES TO SLOWLY MAKE ITS WAY SOUTHWARD TOWARD THE
AREA. DEEP MOISTURE IS CURRENTLY MOVING ASHORE TO THE WEST OVER
SE TX. THIS IS EVIDENT BY THE MARINE TCU AND SHOWERS ALREADY
DEVELOPING OVER THAT WAY. THIS SAME AREA OF MOISTURE WILL HELP
GIVE A SLIGHTLY BETTER CHANCE OF RAIN TO THE BTR AREA TODAY. AN OUTFLOW
BOUNDARY FROM EARLIER CONVECTION TO THE NORTH WILL LAY SOMEWHERE
NEAR MCB AND MAY ALSO GIVE A SLIGHTLY BETTER CHANCE OF RAIN SO
THESE TWO LOCATIONS WERE LEFT WITH HIGHER CHANCE POP NUMBERS THAN
ALL OTHER SITES.

SUPRESSION AHEAD OF THE TROUGH TO THE NORTH WILL HELP HEAT THINGS
UP TODAY. MOISTURE IS VERY THIN OVER THE REMAINING SE HALF OF THE
AREA WHICH WILL ALLOW FOR ONLY A CU FIELD TO DEVELOP. MOISTURE
DEPTH CONTINUES TO CLIMB OVER THE NEXT COUPLE OF DAYS. DEEPER MOISTURE MIXED
WITH THE TROUGH AND DAYTIME HEAING SHOULD GIVE AT LEAST A CHANCE
OF SH/TS OVER THE NORTH TIER OF COUNTIES/PARISHES FOR MONDAY AND TUESDAY.

.LONG TERM...
THE TROUGH AXIS WILL SETTLE NEAR THE GULF COAST AT PASCAGOULA.
FROM THERE...THE TROUGH SHOULD TURN BACK TO THE NW. THIS WILL BE
THE BEST LOCATIONS FOR GETTING WET WED. AFTERWARDS SOME MODERATE
LACK IN CONFIDENCE STARTS AS EASTERLIES BRING A CHANCE OF TS TO
THE WEST SIDE OF THE RIDGE THROUGH SUNDAY. THEN...AND THIS IS TRUE
FOR EVERY MODEL SUITE...SOLUTIONS DRAW A STRONG LATE SEASON COLD
FRONT DIVING SOUTH FROM CANADA AS AN UNUSUALLY STRONG EASTERLY
WAVE MOVE WEST THROUGH THE GULF. SINCE ALL MODEL SOLUTIONS HAVE
SOME TYPE OF SCENARIO LIKE THIS AT ABOUT THE SAME TIMING...IT HELPS
BOOST CONFIDENCE A LITTLE...BUT WOULD LIKE TO SEE A RUN TO RUN
HOLD FOR ABOUT 2 TO 3 DAYS BEFORE STARTING TO INTRODUCE AN
EVENT(SEVERE WX) LIKE THIS.

&&

.AVIATION...
MAINLY VFR CONDITIONS ARE EXPECTED TO PREVAIL AT THE EACH OF THE TAF
SITES THROUGH 12Z MONDAY...ALTHOUGH OCCASIONAL MVFR CEILINGS AND
VISIBILITIES MAY BE OBSERVED DURING THE LATE NIGHT AND EARLY MORNING
HOURS. ISOLATED CONVECTION MAY AFFECT KMCB AND KBTR THIS AFTERNOON
AND TONIGHT AS A FRONTAL BOUNDARY SAGS SOUTH TOWARD THE AREA. 11

&&

.MARINE...
GENERALLY LIGHT ONSHORE FLOW WILL CONTINUE TODAY AND TONIGHT IN
ADVANCE OF A WEAK FRONTAL BOUNDARY THAT WILL SAG SOUTH TOWARD THE
MISSISSIPPI AND SOUTHEAST LOUISIANA COASTS MONDAY AND MONDAY NIGHT.
THIS BOUNDARY WILL BECOME DIFFUSE OR MOVE BACK NORTH TUESDAY WITH A
SURFACE RIDGE AND GENERALLY LIGHT ONSHORE FLOW PREVAILING ACROSS THE
CENTRAL GULF COAST REGION WEDNESDAY AND THURSDAY. 11


New Orleans Local Weather thread - dkmac - 05-11-2009 05:46 AM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
417 AM CDT MON MAY 11 2009

.SHORT TERM...
TROUGH BOUNDARY WILL SLIP A LITTLE FARTHER SOUTH TODAY AND THIS
TIME WE SHOULD SEE SOME ACTIVITY VISIT. SPC HAS TAKEN THE AREA OUT
OF SLIGHT RISK FOR TODAY BUT THERE IS SOME CONCERN ABOUT THIS.
SOUNDING PROFILES INDICATE STRONGER DRYING AT 700MB. TS THAT ARE
CAPABLE OF DEVELOPING WILL PUNCH THROUGH THIS DRY LAYER CAUSING A
LOT OF NEGATIVE BUOYANCY TO THE TS CORE. THIS WASN`T THE CASE
YESTERDAY AND BY TUESDAY THIS LAYER MOISTENS A BIT. SO WILL KEEP
THE WORDING OF SLIGHT RISK OF SEVERE FOR TODAY ESPECIALLY DURING
THE AFTERNOON. WEATHER HAZARDS WILL BE MAINLY DAMAGING STAIGHT
LINE WINDS. SOME HAIL WILL BE POSSIBLE AS WELL BUT THIS DOESN`T
LOOK TO BE THE STRONGEST FEATURE. TUE...THE BOUNDARY RETREATS
SLIGHTLY AND SHOULD BE LOCATED FROM PQL TO MONROE. THIS IS WHERE
THE TS SHOULD ALSO BE LOCATED. THE TROUGH THEN BEGINS TO WEAKEN
FURTHER AND BECOMES UNIDENTIFIABLE BY WED. WITH NO REAL FOCUS FOR
TS ACTIVITY...NO POP GRADIENT CAN BE DRAWN. MOISTURE SCATTERS OUT
AND A FEW SH/TS WILL DOT THE REGION. THU LOOKS TO BE SIMILAR WITH
DEEPER MOISTURE ADDED SO SEVERAL MORE TS CLUSTERS WILL BE FOUND.

.LONG TERM...
FRIDAY IS PROMISING DEEPER MOISTURE YET SO RAIN CHANCES LOOK TO
CLIMB SLIGHTLY HIGHER EACH DAY FROM MID WEEK. SAT AND SUN IS WHERE
THINGS ARE BEGINNING TO LOOK PROBLEMATIC. LOOKING AT SOME
MESOSCALE VARIABLES WITH THE ROS MODEL...A C-BRZ FORMS SAT AND
EASILY DEVELOPS SH/TS ALONG IT. ATTM CAN`T TELL HOW FAR EAST THE
C-BRZ WILL DEVELOP ALONG THE COAST. SAT WILL ALSO INTRODUCE A
STRONG LATE SEASON COLD FRONT TO THE DEEP SOUTH. THIS FRONT IS
ADVERTISED TO MOVE THROUGH OUR AREA SUN. A STRONG FRONT DURING
THIS TIME OF YEAR ONLY SPELLS ONE THING...SEVERE WEATHER.
OBVIOUSLY WE WILL HAVE TO WORK OUT PARAMETERS SUCH AS TIMING AND
PLACEMENT BUT ALL GLOBAL MODEL SUITES ARE TRYING TO INTRODUCE SOME
FORM OF BAROCLINIC SYSTEM WHETHER THAT BE IN THE FORM OF A
PROGRESSIVE TROUGH OR A CUT OFF UPPER LOW OVER THE NORTHERN GULF.
THE GFS WANTS TO PLOW THE FRONT THROUGH THE GULF BY MON. THIS
DOESN`T SEEM TO BE A REASONABLE SOLUTION. FRONTS NORMALLY HAVE A
HARD TIME MAKING THEIR WAY THROUGH THE GULF THIS TIME OF
YEAR...EVEN STRONG ONES. THINKING IS THAT IT WILL STALL SOMEWHERE
OVER THE NORTHERN GULF KEEPING RAIN CHANCES ALIVE OVER THE COASTAL
WATERS MON AND TUE OF NEXT WEEK.

&&

.AVIATION...
FOR 12Z ISSUANCE...MAINLY VFR CONDITIONS ARE EXPECTED TO PREVAIL AT
EACH OF THE TAF SITES THROUGH 12Z TUESDAY...ALTHOUGH OCCASIONAL MVFR
CEILINGS AND VISIBILITIES MAY BE OBSERVED DURING THE LATE NIGHT AND
EARLY MORNING HOURS. ISOLATED TO SCATTERED CONVECTION MAY AFFECT THE
TERMINALS THIS AFTERNOON AND TONIGHT AS A FRONTAL BOUNDARY SAGS
SOUTH INTO THE AREA...ESPECIALLY AT KMCB...KBTR AND KGPT. 11

&&

.MARINE...
GENERALLY LIGHT ONSHORE FLOW WILL CONTINUE TODAY IN ADVANCE OF A
WEAK FRONTAL BOUNDARY THAT WILL SAG SOUTH TOWARD THE MISSISSIPPI AND
SOUTHEAST LOUISIANA COASTS LATER TODAY AND TONIGHT. THIS BOUNDARY
WILL BECOME DIFFUSE TUESDAY WITH A SURFACE RIDGE AND LIGHT TO
OCCASIONALLY MODERATE ONSHORE FLOW PREVAILING ACROSS THE CENTRAL
GULF COAST REGION LATE TUESDAY THROUGH FRIDAY. 11


New Orleans Local Weather thread - dkmac - 05-12-2009 04:10 AM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
324 AM CDT TUE MAY 12 2009

.SHORT TERM...

WEST-NORTHWEST FLOW ALOFT ON THE EASTERN PERIPHERY OF AN UPPER
LEVEL RIDGE OVER THE SOUTHERN PLAINS WILL CONTINUE TO BRING A
SERIES OF WEAK UPPER LEVEL IMPULSE INTO THE REGION. AT THE SAME
TIME...A WEAK STATIONARY FRONT CURRENTLY OVER THE AREA WILL
CONTINUE TO SERVE AS A LOW LEVEL FOCUS FOR CONVECTIVE DEVELOPMENT.
MODEL SOUNDINGS SHOW A HIGHLY UNSTABLE ENVIRONMENT IN PLACE
TODAY...WITH STEEP LAPSE RATES...HIGH CAPE VALUES RUNNING IN THE
2000 TO 2500 J/KG RANGE AND LIFTED INDICES IN THE -4 TO -6 RANGE.
THIS STRONG INSTABILITY COMBINED WITH LOW LEVEL CONVERGENCE ALONG
THE BOUNDARY...AND SOME ENHANCED UPPER LEVEL SUPPORT WILL ALLOW
SCATTERED CONVECTION TO DEVELOP THIS AFTERNOON. THE CONVECTION
WILL BE MOST NOTICEABLE OVER THE NORTHERN HALF OF THE FORECAST
AREA...WITH LESS RAINFALL OVER COASTAL LOCATIONS. THE CONVECTION
WILL BE DIURNAL IN NATURE...AND EXPECT MOST OF THE CONVECTIVE
ACTIVITY TO END IN THE EVENING HOURS.

GOING INTO TOMORROW...IT LOOKS LIKE A BIT MORE STABLE AIRMASS WILL
BE IN PLACE. THE UPPER LEVEL RIDGE OVER THE SOUTHERN PLAINS WILL
BECOME CENTERED OVER THE GULF SOUTH...ALLOWING FOR SOME STRONG MID
AND UPPER LEVEL SUBSIDENCE. ALTHOUGH LOW LEVEL INSTABILITY WILL BE
IN PLACE...EXPECT DRIER AIR ALOFT TO PRODUCE A FAIRLY STRONG MID-
LEVEL CAP. AS A RESULT...HAVE GONE WITH A FAIRLY DRY FORECAST FOR
TOMORROW...WITH SOME ISOLATED POPS POSSIBLE OVER NORTHERN AND
EASTERN...WHERE THE CAP MAY BE A BIT WEAKER. TEMPERATURES WILL
ALSO BE WARMER...AS LESS CLOUD COVER AND STRONGER SOLAR INSOLATION
IS EXPECTED.

HEADING INTO THURSDAY...CONDITIONS WILL ONCE AGAIN BECOME MORE
FAVORABLE FOR CONVECTIVE ACTIVITY...AS THE UPPER LEVEL RIDGE PULLS
TO THE EAST...ALLOWING FOR DEEP SOUTHERLY FLOW OFF THE GULF TO
TAKE ONCE AGAIN TAKE HOLD. WITH MORE MOISTURE IN THE MID-
LEVELS...THE OVERALL CAP WILL BE MUCH WEAKER ON THURSDAY.
HOWEVER...THE UPPER LEVEL SUPPORT WILL BE MUCH LOWER THAN
TODAY...RESULTING IN LESS OVERALL CONVECTIVE COVERAGE. HAVE GONE
WITH A GENERAL LOW END CHANCE POP FOR THURSDAY TO REFLECT THE
WEAKENED CAP AND WEAKER DYNAMIC FORCING ALOFT. TEMPERATURES WILL
REMAIN ABOVE NORMAL...AS THE INFLUENCE OF THE UPPER LEVEL RIDGE IS
STILL FELT.

.LONG TERM...

HEADING INTO THE WEEKEND...THE MEDIUM RANGE MODELS ARE IN
EXCELLENT AGREEMENT ON THE OVERALL PATTERN. BOTH MODELS SHOW THE
UPPER LEVEL RIDGE OVER FLORIDA WEAKENING FRIDAY INTO SATURDAY. AT
THE SAME TIME...A STRONG TROUGH OVER THE ROCKIES WILL BEGIN TO
PULL TO THE EAST. THIS STRONG TROUGH WILL FORCE A FRONTAL BOUNDARY
TOWARD THE AREA THROUGH THE WEEKEND...WITH FRONTAL PASSAGE
EXPECTED SUNDAY NIGHT INTO MONDAY.

FOCUSING ON FRIDAY AND SATURDAY...IT APPEARS THAT A WEAK UPPER
LEVEL VORT LOBE WILL KICK OUT OF SOUTH TEXAS AND PULL INTO THE
LOWER MISSISSIPPI VALLEY ON FRIDAY. WITH AMPLE INSTABILITY IN
PLACE...THE ENHANCED OMEGA VALUES ASSOCIATED WITH THIS VORT LOBE
WILL ALLOW FOR GREATER CONVECTIVE DEVELOPMENT ON FRIDAY. WITH THIS
IN MIND...HAVE BUMPED UP POPS TO HIGH END CHANCE...ESPECIALLY FOR
NORTHERN AND WESTERN ZONES...WITH CHANCE POPS ELSEWHERE. THE
BIGGEST CHANGE IN THINKING TAKES PLACE IN THE OVERNIGHT HOURS. AS
THE INITIAL VORT LOBE PULLS BY...CONTINUED POSITIVE VORTICITY
ADVECTION WILL TAKE HOLD IN ADVANCE OF THE DEEPENING TROUGH OVER
THE ROCKIES. THIS PVA WILL KEEP ISOLATED POPS IN FRIDAY
NIGHT...WITH CHANCE POPS ONCE AGAIN RETURNING FOR SATURDAY.
HOWEVER...THE OVERALL FORCING WILL STILL BE LESS THAN ON FRIDAY
WHEN THE VORT MAX PULLED BY...AND EXPECT LESS OVERALL CONVECTIVE
ACTIVITY. WITH THIS IN MIND...HAVE WENT WITH LOW END CHANCE POPS
FOR SATURDAY. TEMPERATURES WILL REMAIN WARM...BUT SHOULD BE A BIT
COOLER ON FRIDAY DUE TO EXPECTED INCREASE IN CLOUD COVER AND
THUNDERSTORM ACTIVITY.

THE UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT WILL BEGIN TO
PULL INTO THE LOWER MISSISSIPPI VALLEY SATURDAY NIGHT INTO SUNDAY.
MODEL SOUNDINGS SHOW A SHARP INCREASE IN INSTABILITY ON
SUNDAY...AS LAPSE RATES INCREASE AND CAPE VALUES SHOOT UP INTO THE
2000 TO 3000 J/KG RANGE. THE STRONGEST INSTABILITY WILL NEAREST TO
THE FRONT AND UPPER LEVEL TROUGH AXIS...AND HAVE PUT IN HIGHER
POPS FOR NORTHERN AND WESTERN ZONES TO REFLECT THIS.
HOWEVER...STRONG MID-UPPER LEVEL OMEGA VALUES ACROSS THE REGION
WILL SUPPORT SOLID CHANCE POPS ACROSS THE CWA FOR SUNDAY. THESE
HIGHER POPS WILL PERSIST INTO SUNDAY NIGHT AS THE FRONTAL BOUNDARY
AND TROUGH AXIS SLOWLY PULL THROUGH THE REGION. WITH THE EXPECTED
RAINFALL...OVERALL TEMPERATURES WILL BE SOMEWHAT CLOSER TO NORMAL
SUNDAY. BY MONDAY...THE FRONT SHOULD BE TRANSITING THROUGH THE
CWA. EXPECT CONTINUED CHANCE POPS DUE TO STRONG LOW LEVEL
CONVERGENCE ALONG THE FRONT AND AMPLE LIFT ALOFT. HOWEVER...THE
BEST INSTABILITY WILL SHIFT TO THE COASTAL PORTIONS OF THE
CWA...AS THE FRONT BEGINS TO SHIFT INTO THE NORTHERN GULF. IN
FACT...BY MONDAY NIGHT...EXPECT LOWER HUMIDITIES AND MORE STABLE
AIR TO BEGIN TAKING HOLD OF NORTHERN AND WESTERN ZONES. WITH A
MUCH DRIER AIRMASS ADVECTING IN...EXPECT COOLER OVERNIGHT LOWS
MONDAY NIGHT...ESPECIALLY OVER INLAND AREAS. TUESDAY WILL BE
WARM AND DRY...WITH LOWER HUMIDITIES...AS A STRONG SURFACE RIDGE
BUILDS IN FROM THE NORTH...AND AN UPPER LEVEL RIDGE BEGINS TO
STRENGTHEN OVER THE SOUTHERN PLAINS.

&&

.AVIATION...
FOR 12Z ISSUANCE...CONSIDERABLE VARIABILITY WILL EXIST AMONG THE TAF
SITES DURING THE EARLY MORNING HOURS TODAY WITH CONDITIONS MAINLY IN
THE VFR TO MVFR RANGE...HOWEVER IFR CEILINGS WILL BE POSSIBLE AT
TIMES AT KBTR AND KMCB THROUGH 14Z. A SHOWER OR THUNDERSTORM IS ALSO
POSSIBLE EARLY THIS MORNING AT KGPT. IN GENERAL...VFR CONDITIONS
WILL PREVAIL FOR THE BALANCE OF THE DAY WITH SCATTERED MAINLY
AFTERNOON CONVECTION POSSIBLY AFFECTING EACH OF THE TAFS SITES.
MVFR CEILINGS AND VISIBILITIES WILL BE POSSIBLE AGAIN LATE TONIGHT
AND EARLY WEDNESDAY MORNING. 11

&&

.MARINE...
THE WEAK FRONTAL BOUNDARY DRAPED NEAR THE MISSISSIPPI COAST AND
EXTENDING WESTWARD INTO SOUTHEAST LOUISIANA WILL BECOME DIFFUSE AND
MOVE NORTHWARD TODAY. GENERALLY LIGHT ONSHORE FLOW WILL PREVAIL OR
DEVELOP BY THIS AFTERNOON. IN THE WAKE OF THIS BOUNDARY...A SURFACE
RIDGE WILL BUILD ACROSS THE GULF COAST AND WILL PREVAIL THROUGH THE
END OF THE WEEK. LIGHT TO OCCASIONALLY MODMODERATE ONSHORE FLOW IS
EXPECTED ACROSS THE CENTRAL GULF COAST REGION THROUGH SATURDAY. 11


New Orleans Local Weather thread - dkmac - 05-13-2009 05:37 AM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
357 AM CDT WED MAY 13 2009

.SHORT TERM...

ALTHOUGH AN UPPER LEVEL RIDGE WILL BE TRANSITING THROUGH THE
REGION TODAY...IT APPEARS THAT NORTHERN AND EASTERN ZONES WILL SEE
AT LEAST A CHANCE FOR SOME SCATTERED CONVECTIVE DEVELOPMENT.
OVERALL...THE RIDGE AXIS WILL LEAD TO SOME DRIER AIR WORKING INTO
THE MID-LEVELS...WHICH AS THE LATEST MODEL SOUNDINGS SUGGEST WILL
LEAD TO A WEAK MID-LEVEL CAP. THIS MID-LEVEL CAP WILL BE STRONGEST
NEAR THE LOUISIANA AND COAST AND THE ATCHAFALAYA BASIN...WITH VERY
LITTLE CAPPING SUGGESTED TOWARD THE MISSISSIPPI COAST. IN
ADDITION...ONGOING SHOWER DEVELOPMENT LATE TONIGHT ALONG THE
MISSISSIPPI COAST AND IN THE FLORIDA PARISHES...SUPPORTS THE
THINKING THAT THERE WILL BE GREATER INSTABILITY IN THIS REGION
TODAY. WITH THIS IN MIND...HAVE GONE WITH SLIGHT CHANCE POPS FOR
SOUTHERN AND WESTERN ZONES...AND LOW END CHANCE POPS FOR EASTERN
AND NORTHERN ZONES. TEMPERATURES WILL BE SIMILAR TO
YESTERDAY...WITH HIGH REACHING INTO THE MIDDLE TO UPPER 80S. THE
CONVECTIVE ACTIVITY WILL BE DIURNAL IN NATURE...WITH LITTLE
ACTIVITY EXPECTED TONIGHT. SIMILAR CONDITIONS ARE EXPECTED FOR
THURSDAY...BUT THERE SHOULD BE A BIT MORE INSTABILITY...WITH CAPE
VALUES CLIMBING FROM AROUND 1000 J/KG TO AROUND 2000 J/KG. THIS IS MAINLY
DUE TO THE MID-LEVEL CAP ERODING...AND THE UPPER LEVEL RIDGE AXIS
SLIDING TO THE EAST. DEEPER MOISTURE WILL ADVECT IN...THUS ALLOWING
FOR GREATER CONVECTIVE COVERAGE IN THE AFTERNOON HOURS. HAVE GONE
WITH LOW END CHANCE POPS FOR ALL ZONES. TEMPERATURES WILL REMAIN
ABOVE NORMAL.

BY FRIDAY...CONDITIONS WILL BECOME MUCH MORE UNSETTLED ACROSS THE
REGION. IN THE MID AND UPPER LEVELS...THE RIDGE AXIS WILL BE
PARKED OVER FLORIDA...ALLOWING FOR DEEP SOUTHERLY FLOW OFF THE
GULF TO CONTINUE. ALOFT...IT APPEARS THAT A WEAK UPPER LEVEL VORT
LOBE WILL SWING THROUGH THE REGION. ENHANCED UPPER LEVEL LIFT IN
THE VICINITY OF THIS VORT LOBE WILL ALLOW FOR GREATER CONVECTIVE
DEVELOPMENT FRIDAY AFTERNOON INTO FRIDAY EVENING. MODEL SOUNDINGS
SHOW DECENT LAPSE RATES AND HIGH CAPE VALUES IN THE 2000-3000 J/KG
RANGE FRIDAY AFTERNOON. WITH LITTLE TO STOP CONVECTION FROM
FORMING...EXPECT HIGH END CHANCE POPS FOR INLAND ZONES...WITH LOW
END CHANCE POPS CLOSER TO THE COAST. THROUGHOUT THE SHORT TERM
PERIOD...MODEL SOUNDINGS INDICATE THAT LAPSE RATES WILL SUPPORT
THE DEVELOPMENT ISOLATED SEVERE THUNDERSTORMS. THESE STORMS COULD
PRODUCE HAIL AND WET MICROBURSTS.

.LONG TERM...

HEADING INTO THE WEEKEND...THE UPPER LEVEL RIDGE OVER THE GULF AND
EASTERN SEABOARD WILL BREAK DOWN A BIT...ALLOWING AN UPPER LEVEL
TROUGH TO DIG INTO THE PLAINS STATES. BOTH THE GFS AND ECMWF
DEPICT THIS SCENARIO...SO OVERALL CONFIDENCE IS HIGH. AS THE TROUGH
DEEPENS...AN AREA OF LOW PRESSURE WILL FORM OVER THE MID- SOUTH
AND QUICKLY LIFT TOWARD THE NORTHEAST. AS THE LOW FORMS...COLDER
AND DRIER AIR OVER THE UPPER PLAINS WILL BE DRAWN SOUTHWARD
RESULTING IN THE FORMATION OF A COLD FRONT. IN ADVANCE OF THE
SYSTEM ON SATURDAY...CONDITIONS WILL BE SOMEWHAT SIMILAR TO FRIDAY
WITH DEEP MOISTURE FLOWING IN FROM THE GULF AND LITTLE IN THE WAY
OF CONVECTIVE INHIBITION TO STOP DIURNALLY FORCED CONVECTION TO
DEVELOP. ALOFT...A BROAD AREA OF LIFT WILL DEVELOP OVER THE
REGION...AS STRONG POSITIVE VORTICITY ADVECTION TAKES HOLD. THIS
BROAD AREA OF ENHANCED LIFT COMBINED WITH HIGH CAPE VALUES WILL
ALLOW FOR CHANCE POPS OVER INLAND ZONES WITH LOWER POPS NEAR THE
COAST WHERE INSTABILITY IS A BIT LESS DUE TO THE COOLER GULF
WATERS.

THE UPPER LEVEL TROUGH AXIS WILL SWEEP THROUGH ON SUNDAY...ABOUT
THE SAME TIME AS THE SURFACE FRONT SLIDES THROUGH. STRONG FORCING
ALONG THE FRONT COMBINED WITH DEEP LIFT THROUGHOUT THE ATMOSPHERIC
COLUMN WILL SUPPORT CONVECTIVE DEVELOPMENT THROUGHOUT THE DAY
SUNDAY AND INTO SUNDAY EVENING. HAVE WENT WITH HIGH END CHANCE
POPS FOR ALL ZONES ON SUNDAY. WITH THE AMOUNT OF CONVECTION
EXPECTED...TEMPERATURES WILL BE QUITE A BIT COOLER WITH HIGHS
FALLING BACK TO MORE NORMAL LEVELS FOR THIS TIME OF YEAR.

GOING INTO EARLY NEXT WEEK...THE MODELS DIVERGE A BIT...WITH THE
GFS A BIT FASTER THAN THE ECMWF ON THE FRONT CLEARING THE AREA.
HAVE WENT WITH A BLEND OF THE MODELS...WITH GREATER WEIGHT TOWARD
THE GFS. KEEP SOME POPS IN SUNDAY NIGHT...BUT GO WITH A DRY
FORECAST FOR MONDAY...AS STRONG DRY AIR ADVECTION AND SUBSIDENCE
IN THE WAKE OF THE TROUGH AXIS SHOULD DOMINATE. WITH A MUCH DRIER
AIRMASS IN PLACE...EXPECT A LARGER DIURNAL RANGE IN TEMPERATURES
EARLY NEXT WEEK. DAYTIME HIGHS WILL STILL WARM INTO THE LOWER TO
MIDDLE 80S...BUT OVERNIGHT LOWS...ESPECIALLY OVER INLAND ZONES
SHOULD DIP INTO THE MIDDLE TO UPPER 50S. STRONG RIDGING AT THE
SURFACE AND ALOFT WILL BUILD IN ON TUESDAY...AND REMAIN IN PLACE
THROUGH WEDNESDAY. THIS DEEP RIDGING WILL KEEP CONDITIONS
DRY...AND ALLOW A RETURN TO TEMPERATURES NEAR 90 DEGREES BY
WEDNESDAY.

&&

.AVIATION...
FOR 12Z ISSUANCE...MVFR CEILINGS AND VISIBILITIES WILL IMPACT THE
TAF SITES EARLY THIS MORNING BEFORE IMPROVING TO VFR CONDITIONS FOR
THE REMAINDER OF THE DAY. ISOLATED TO SCATTERED CONVECTION WILL
PRIMARILY THREATEN DURING THE THE AFTERNOON HOURS...WITH THE BEST
CHANCES AT KMCB AND KGPT. AGAIN LATE TONIGHT AND EARLY THURSDAY
MORNING MVFR CEILINGS AND VISIBILITIES WILL BE POSSIBLE...ESPECIALLY
AT KMCB AND KBTR. 11

&&

.MARINE...
A SURFACE RIDGE WILL DOMINATE THE CENTRAL GULF COAST REGION THROUGH
THE END OF THE WEEK WITH GENERALLY LIGHT TO OCCASIONALLY MODERATE ONSHORE
FLOW PREVAILING. A COLD FRONT IS EXPECTED TO ENTER THE COASTAL
WATERS SUNDAY OR SUNDAY NIGHT. 11