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New Orleans Local Weather thread - dkmac - 10-16-2008 05:55 AM

000
fxus64 klix 160957
afdlix

area forecast discussion
national weather service new orleans la
457 am cdt thu oct 16 2008

.short term...
Strong radiational cooling from mostly clear skies and calm winds
has caused boundary layer saturation and areas of fog early this
morning with dense fog reported at kmcb and kpql. Will continue to
monitor observations and may have to issue a dense fog advisory
for portions of the area if the fog persists and expands.

Another lingering issue is the higher than normal tides over lakes
maurepas and pontchartrain and the east facing gulf coast from bay
st. Louis to the mouth of the mississippi river...which are
running 1 to 2 feet above normal. Southeast winds over the marine
area have died down to 10 to 15 knots which will not add much if
any additional push of water before winds shift to northerly
with the cold front late tonight and friday. Will continue to
carry the coastal flood advisory for areas experiencing high tide
early this morning. Higher tide ranges means the water should drop
off more dramatically at the time of low tide later this morning
and afternoon...so the advisory may need to be canceled later this
morning.

Large scale pattern will feature a sagging jetstream with upper
level disturbances running through. This will help nudge a cold
front into southwest mississippi and central louisiana late this
afternoon. It appears the best lift from the front and upper
divergence will be north and west of the forecast area...so have
only gone with a 30 or higher pop from near baton rouge to mccomb
and areas northwest today. Not much instability is expected...so
will carry a chance of showers and only a slight chance of
thunderstorms.

Some better lift from the front and upper jet dynamics will
affect the far north and northwest zones tonight...then spread
southeast across most of the land areas on friday. Instability
will not have a chance to increase with the cold front sliding
through the forecast area... So will carry a decent chance of
showers...but only a slight chance of thunderstorms.

.long term...
The cold front will push through the remainder of the forecast
area friday night and the outer coastal waters saturday morning.
Much drier and somewhat cooler air...especially at night...will
overspread the area friday through the weekend. Temperatures will
be near to slightly below normal for several days as canadian high
pressure builds over the area. Surface will slide east early next
week...so temperatures and humidity will gradually rise...but it
will remain dry...and much more comfortable than the muggy last
several days.

&&

.aviation...
Saturated to nearly saturated surface conditions will result in
fog at the kmcb...kbtr...and kgpt early this morning with vlifr
conditions at times through 14z. After fog burns off...mainly vfr
weather is expected through early this evening. Cold front and
increasing low level moisture will result in ifr cigs late tonight
into friday morning.

.marine...
Southeast to south winds 10 to 15 knots ahead of cold front will
shift to northerly 10 to 15 knots friday...then increase to 20
knots or greater saturday morning as dry cool air moves over the
warm water.


New Orleans Local Weather thread - dkmac - 10-17-2008 05:23 AM

000
fxus64 klix 170950
afdlix

area forecast discussion
national weather service new orleans la
450 am cdt fri oct 17 2008

.short term...
Cold front has slowly moved through kmcb and kbtr over the last
one to two hours. Water vapor satellite imagery shows a deepening
shortwave trough over the central plains with the upper jetstream
getting suppressed south. A stream of mid/upper moisture from the
western gulf of mexico will continue to feed into both sides of
the slow moving frontal boundary today. Some rain and shower
activity is finally breaking out over southwest mississippi...and
am expecting an increase in activity through the day as weak pva
and upper divergence from the right entrance region of the upper
jet interact with plentiful moisture with precipitable water
values near 2 inches. Given the low coverage thus far...have gone
with a compromise pop number today...higher than the gfs mav and
lower than the nam met.

Tonight...the cold front will clear the coastal waters as a mid
level shortwave trough moves southeast across the southeast
states. Any lingering isolated showers or patchy light rain over
the mississippi coast and south of lake pontchartrain/coastal
southeast louisiana will end during the evening with clouds
decreasing and clearing out from northwest to southeast. Much
cooler air will surge into the area with lows in the 50s expected
over most areas except near the south shore of lake pontchartrain
and the immediate southeast louisiana coast.

Clear skies and dry/pleasant conditions will prevail on saturday
with even cooler lows expected saturday night.

.long term...
High pressure will dominate on sunday with clear skies and
pleasant temperatures. The influence of high pressure will hold
monday into tuesday with dry weather continuing.

During the middle of next week...the gfs and ecmwf both show a
large and deep stacked low pressure system developing over the mid
part of the country as some type of tropical disturbance or low
meanders over the western caribbean sea. The gfs tries to bring
low pressure out of the caribbean sea into the gulf of mexico
while the ecmwf keeps any low suppressed over the caribbean sea.
Too early to say how this will play out. Some slight tap of
tropical moisture may try to interact with the mid latitude
cyclone over the plains...so have a slight chance of showers
wednesday night and thursday.

&&

.aviation...
Ifr conditions will be the rule today for all sites as a slow moving
cold front brings ceilings down to around bkn-ovc004. Chances of
rain will be highest at mcb today where a tempo group should
suffice. Prob30 groups will cover the remaining terminals. A wind shift
to the northwest and north with a slight increase in wind speeds can
be expected after the front moves through.

$$

.marine...
A cold front will move through the coastal waters tonight. Winds and
seas will build behind the front due to a tight pressure gradient as
a high builds into the region. Small craft advisories may be
necessary by early saturday. The high will remain in place
through the first part of next week.

Tides are beginning to slowly recede today and no further increase
in water levels is expected. But tides will remain around a foot
above normal today in the tidal lakes. For this reason...the coastal
flood advisory has been canceled.


New Orleans Local Weather thread - dkmac - 10-18-2008 05:47 AM

000
fxus64 klix 180945
afdlix

area forecast discussion
national weather service new orleans la
445 am cdt sat oct 18 2008

.short term...
Cold front has cleared the coastal waters and cooler and drier air
has surged into the forecast area overnight. Ir and water vapor
imagery show clouds clearing the coast and the deep layer dry air
moving in as the mid/upper trough moves into the southeast states.
This makes the next couple days a temperature forecast since there
will be no cloud cover. Based on current and past mav mos
trends...will go right with or a degree lower for highs...and
generally a couple degrees lower tonight to blend with the lower
met guidance tonight. New orleans metro will see quite a range of
temperatures for lows with the winds off the 70s lake
pontchartrain waters. Areas near the mississippi river and on the
west bank will be as much as 5 or more degrees cooler than areas
near the immediate lakefront. Same goes for southeast louisiana
coastal areas where marine influences come into play. There will
be plenty of upper 40s over the cooler northern/inland areas the
next couple nights which will be the coolest of the season thus
far.

.long term...
Warmer and slightly more humid weather will return monday and
tuesday as surface high pressure shifts east and mid level high
pressure builds over the gulf coast region. It will remain dry.

Models diverge quite a bit amongst each other and from run to run
during the wednesday through next saturday time frame. This is
significant since there will be a deep stacked low pressure system
developing over the mid part of the country. The 00z gfs has made
a significant shift to the south and southeast thursday into
friday with the mid/upper low moving southeast into the lower ms
valley while the 00z ecmwf moves the low northeast towards the
great lakes saturday. Will go with a compromise solution for
now...but would not be surprised to see the gfs end up closer
given the position of other systems off the northwest and
northeast coasts. Have not made any significant changes except to
increase the chance of rain and convection slightly on wednesday
night and lowered temperatures closer to the latest mex during the
thursday and friday time frame.

&&

aviation...
Mvfr visibilities at kgpt should be temporary this morning...with
skc and p6sm expected at all sites by midmorning and for the
remainder of the forecast. Wind speeds will be in the 10 to 15 kt
range for the afternoon hours...but die off this evening at all but
kmsy. 35

&&

.marine...
Precipitation moving southward out of our coastal waters. Cold air
advection will keep winds in the exercise caution category over the
coastal waters through sunday morning. Could reach advisory criteria
for a short time...but confidence not high enough to go with an
advisory. Over the tidal lakes...winds should stay just below
headline criteria. Seas running 2 to 4 feet should come up another
foot or two...but stay below 7 feet.

High pressure moves in on sunday with winds and seas subsiding
somewhat for the first half of the work week. Next cold front
appears to be on thursday...with winds approaching advisory criteria
again on thursday night. 35


New Orleans Local Weather thread - ROLLTIDE - 10-19-2008 04:14 AM

NATIONAL WEATHER SERVICE NEW ORLEANS LA
339 AM CDT SUN OCT 19 2008

.SHORT TERM...
LARGE BROAD RIDGE OF SURFACE HIGH PRESSURE...EXTENDING FROM THE
CANADIAN ATLANTIC PROVINCES TO THE SOUTHERN PLAINS...WILL REMAIN
IN PLACE TODAY AS THE MID/UPPER LOW/TROUGH MOVES EAST OFF THE
EASTERN SEABOARD. DRY NORTHERLY FLOW WILL KEEP SKIES CLOUD FREE
AND THE COOL MORNING TEMPERATURES WILL WARM TO VERY PLEASANT
READINGS IN THE MID 70S THIS AFTERNOON WITH LOW HUMIDITY.

TONIGHT SHOULD BE THE COOLEST NIGHT OF THE NEXT 7 DAYS AS THE
SURFACE RIDGE SETTLES A BIT FARTHER SOUTH. MID LEVEL HIGH PRESSURE
WILL BE BUILDING IN FROM THE WEST TONIGHT AND MONDAY AS THE SURFACE
HIGH SLIDES EAST. THIS WILL ALLOW HIGH TEMPERATURES ON MONDAY TO
REBOUND BACK TO THE UPPER 70S UNDER SUNNY SKIES.

.LONG TERM...
HIGH PRESSURE WILL WEAKEN AT ALL LEVELS ON TUESDAY...BUT BENIGN
WEATHER WILL CONTINUE WITH SLIGHTLY WARMER TEMPERATURES EXPECTED.

SUBTLE DIFFERENCES EXIST AMONGST THE MODELS WITH THE EVOLUTION OF
A CUT-OFF LOW OVER THE CENTRAL U.S. WEDNESDAY AND THURSDAY...THEN
A BIGGER SPREAD IN THE GUIDANCE IS NOTED FRIDAY AND SATURDAY. THE
00Z GFS AND ECMWF HAVE EFFECTIVELY SWAPPED SOLUTIONS FROM 24
HOURS AGO. THE ECMWF IS NOW FURTHEST SOUTH WITH THE DEEP MID/UPPER
LOW MEANDERING AND MOVING EAST FROM NEAR THE MISSOURI/ARKANSAS
BORDER TO TENNESSEE DURING THE THURSDAY NIGHT TO SATURDAY TIME
FRAME WHILE THE GFS MOVES THE UPPER SYSTEM ACROSS THE MISSOURI
VALLEY AND NORTH OF THE OHIO VALLEY. EITHER WAY...THIS SYSTEM IS
NOT LIKELY TO BRING WIDESPREAD RAINFALL TO THE FORECAST AREA SINCE
THE BETTER DYNAMICS AND FRONTAL CONVERGENCE WILL BE TO THE NORTH.
HAVE CONTINUED A CHANCE OF SHOWERS DURING THE LATE WEDNESDAY TO
THURSDAY NIGHT TIME FRAME AND DOWNPLAYED THE CHANCE OF
THUNDERSTORMS. TEMPERATURES WILL BE WARMEST ON WEDNESDAY...THEN
COOL DOWN WITH THE UPPER TROUGH AND COLD FRONTAL PASSAGE THURSDAY.
TEMPERATURES COULD BE QUITE A BIT COOLER THAN INDICATED FRIDAY AND
FRIDAY NIGHT IF THE MORE SOUTHERN ECMWF SOLUTION PANS OUT. 22

&&


New Orleans Local Weather thread - ROLLTIDE - 10-20-2008 06:52 AM

NATIONAL WEATHER SERVICE NEW ORLEANS LA
455 AM CDT MON OCT 20 2008

.SHORT TERM...
DRY HIGH PRESSURE WILL REMAIN IN CONTROL TODAY THROUGH TUESDAY
NIGHT. AFTER A COOL START...TEMPERATURES WILL WARM INTO THE MID TO
UPPER 70S WITH CONTINUED LOW HUMIDITY THIS AFTERNOON. MOSTLY CLEAR
SKIES TONIGHT WILL ALLOW TEMPERATURES TO FALL TO BELOW NORMAL
LEVELS AGAIN TONIGHT. SURFACE HIGH PRESSURE WILL BE SHIFTING EAST
ON TUESDAY...AND TEMPERATURES WILL BE NEAR TO SLIGHTLY ABOVE
NORMAL WITH SLIGHTLY NIGHER HUMIDITY.

.LONG TERM...
MAIN WEATHER FEATURE WILL BE A DEEPENING LOW PRESSURE SYSTEM OVER
THE CENTRAL PLAINS THAT WILL BECOME CUT-OFF WEDNESDAY INTO
THURSDAY. AT THE SAME TIME...DEEP MOISTURE WILL GET PULLED NORTH
FROM THE CARIBBEAN SEA AND YUCATAN PENINSULA AREA INTO THE
SOUTHEAST AND EAST CENTRAL GULF OF MEXICO. THE NATIONAL HURRICANE
CENTER IS WATCHING A BROAD AREA OF LOW PRESSURE OVER THE NORTHWEST
CARIBBEAN SEA WHICH WILL MOVE TOWARDS BELIZE AND THE YUCATAN
PENINSULA IN A DAY OR TWO. IT APPEARS THE GFS PULLS THE TROPICAL
MOISTURE TOO FAR NORTH TOO FAST TOWARDS THE CENTRAL GULF COAST...
SO WILL LOOK FOR INCREASED MOISTURE MOSTLY FROM FRONTAL LIFT...PVA
AND MID AND UPPER DIVERGENCE ASSOCIATED WITH THE UPPER LOW.
DESPITE LATITUDINAL DIFFERENCES AND SOME TIMING ISSUES WITH THE
MODELS...THE GFS MEX POP AND TEMPERATURES GUIDANCE LOOKS PRETTY
GOOD FOR THE MOST PART. LOOK FOR BEST CHANCE OF SHOWERS AND
ISOLATED THUNDERSTORMS STARTING MAINLY WEST WEDNESDAY NIGHT...THE
ENTIRE AREA THURSDAY...THEN SHIFTING EAST AND ENDING THURSDAY
NIGHT.

MODEL DIFFERENCES WITH THE MID/UPPER LOW LATE THURSDAY THROUGH
SATURDAY CONTINUE WITH THE LATEST 00Z GFS AND ECMWF RUNS HAVING
FLIP-FLOPPED ONCE AGAIN. THIS TIME...THE GFS IS BACK TO BEING
FARTHER SOUTH OVER THE OZARKS TO TENNESSEE VALLEY WHILE THE ECMWF
IS FARTHER NORTH. ALSO IN QUESTION IS THE STRENGTH OF ANOTHER
SHORTWAVE TROUGH DIVING SOUTH INTO THE SOUTHEAST U.S. IT APPEARS
THIS WILL TRENDS TEMPERATURES TO THE COOL SIDE OF CLIMO BY LATE
NEXT WEEKEND. 22

&&


New Orleans Local Weather thread - dkmac - 10-21-2008 06:11 AM

000
fxus64 klix 210837
afdlix

area forecast discussion
national weather service new orleans la
337 am cdt tue oct 21 2008

.discussion...
An upper trough moving into the northern rockies today is forecast
to dig southeast into the middle part of the country wednesday...
Carving out a large closed low over the central plains that will
eventually be our primary weather maker for the forecast period.
This closed low is forecast to move fairly slowly eastward across
the mississippi valley during the later half of the work week and
across the eastern conus into the weekend. Models due vary considerably
with the speed of this system with both the nam and ecmwf being
faster than the gfs...and the gfs suffering from poor run to run
continuity. As a result...confidence is rather low with the
timing of this system and the passage of its associated cold
front. At this time...we plan to move the cold front slowly east
across the forecast area thursday and thursday night. Models do
pick up on an inverted trough and perhaps even a surface low along
the trough moving north across the gulf of mexico just ahead of
this system. Moisture is forecast to increase and deepen ahead of
the approaching system with precipitable water increasing to
values in excess of 1.5 inches. Some decent lift will be possible
in association with an upper level jet in the late wednesday into
thursday time frame...but again differences exist with the various
models. Plan to go no higher than 50 percent pops...on thursday...
But it is possible that coverage could be greater. Will end pops
from west to east on friday.

Dry weather will return for the weekend as northwest flow prevails
from the weekend into the beginning of next week.

&&

.aviation...
Light winds will allow patchy ground fog to develop near some of the
taf sites. Vsby restrictions are not expected anywhere other than
mcb where a few hours of mvfr vsbys may be possible near daybreak.
Any fog should lift quickly after sunrise with winds picking back up
into the 5 to 10 kt range during the afternoon hours...before
calming again overnight with a return of the ground fog scenario.
Any significant cloud cover should hold off until after 18z
wednesday. 35

&&

.marine...
No marine issues through about the front 36 hours of the forecast.
After that...confidence is low in the particulars of the forecast.
Trending toward the slower gfs/ecmwf forecast on movement of upper
low and associated surface feature timing. These are 18-24 hours
slower than the nam. Models indicate an inverted trof over the gulf
of mexico on thursday. Low pressure is expected to form along the
front/trof and move north or northeast. Gfs solution would bring a
defined surface low northward through the area...while the ecmwf
takes it northeast through the florida peninsula. These differences
would have a significant effect on wind direction and speed. For
now...gfs solution has been employed...but confidence rather low on
details. Expect winds to reach exercise caution levels overnight
wednesday night...then move into the advisory category on thursday.
Expect headlines probably from wednesday night into saturday.
Mariners planning to be out on the gulf of mexico during that time
should stay abreast of the latest forecasts. 35


New Orleans Local Weather thread - dkmac - 10-22-2008 05:40 AM

000
FXUS64 KLIX 220850
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
350 AM CDT WED OCT 22 2008

.DISCUSSION...
DIGGING MID/UPPER LEVEL TROUGH MOVING INTO THE PLAINS WILL EVOLVE
INTO A CLOSED LOW OVER THE CENTRAL/SOUTHERN PLAINS TODAY THAT WILL
MOVE SLOWLY EASTWARD ACROSS THE MID MISSISSIPPI VALLEY THROUGH THE
END OF THE WORK WEEK AND INTO THE EASTERN CONUS OVER THE WEEKEND.
AS THIS FEATURE APPROACHES...MOISTURE WILL BE DRAWN NORTHWARD FROM
THE GULF AND WILL DEEPEN WITH TIME WITH PRECIPITABLE WATER VALUES
FORECAST TO INCREASE TO NEAR 1.75 INCHES TONIGHT INTO THURSDAY.
INSTABILITY WILL BE SOMEWHAT LIMITED...THEREFORE ONLY ISOLATED TO
SCATTERED THUNDERSTORMS WILL BE MIXED IN WITH THE NUMEROUS SHOWERS
EXPECTED THURSDAY INTO THURSDAY NIGHT. THE COLD FRONT ASSOCIATED
WITH THE SYSTEM WILL ADVANCE SLOWLY EAST ACROSS THE FORECAST AREA
THURSDAY WITH AN INVERTED TROUGH OVER THE GULF ALSO BRUSHING THE
AREA. DRIER AIR WILL FILTER INTO THE AREA BEGINNING ON FRIDAY WITH
LEFT SHOWERS ENDING FROM WEST TO EAST. DRY WEATHER WILL BE IN THE
OFFING OVER THE WEEKEND AND INTO NEXT WEEK WITH NORTHWEST FLOW
ALOFT PREVAILING AS THE AFOREMENTIONED SYSTEM MOVES EAST AND A
DEEP TROUGH DEVELOPS OVER THE EASTERN CONUS. SURFACE HIGH PRESSURE
BUILDING INTO THE GULF COAST REGION IN THE WAKE OF THE COLD FRONT
WILL BE REINFORCED EARLY NEXT WEEK.

&&

.AVIATION...
LOOKING AT VFR CONDITIONS THROUGH 00Z...WITH THE EXCEPTION OF SOME
ISOLATED MVFR TO IFR VISIBILITIES IN FOG THIS MORNING...MOST NOTABLY
AT KMCB. THE INVERSION SHOULD BREAK BY 14Z...WITH A RETURN TO VFR
CONDITIONS FOR ALL OF THE TERMINALS. AS INVERTED TROF OVER THE GULF
APPROACHES...MID AND HIGH LEVEL CLOUDS WILL FILTER IN THROUGH THE
DAY...GRADUALLY LOWERING THROUGH THE AFTERNOON. MVFR CEILINGS AND
VISIBILITIES WILL ADVANCE FROM THE SOUTH AFTER SUNSET...REACHING THE
INTERSTATE 10 AND 12 CORRIDORS AROUND 02Z...WITH THE POTENTIAL FOR
SOME LIGHT RAIN. NO THUNDER ANTICIPATED THROUGH 06Z THURSDAY. 35

&&

.MARINE...
A STRONG AREA OF LOW PRESSURE OVER THE CENTRAL PLAINS IS ALLOWING
FOR STRONGER GRADIENT FLOW FROM THE SOUTHEAST TO TAKE HOLD. THE
GRADIENT SHOULD CONTINUE TO TIGHTEN TONIGHT...AS ANOTHER AREA OF LOW
PRESSURE FORMS IN THE CENTRAL GULF OF MEXICO. THIS WILL GRADUALLY
ALLOW CONDITIONS TO MOVE INTO THE EXERCISE CAUTION CATEGORY LATE
THIS AFTERNOON OR EVENING. WILL LEAVE OUT HEADLINE FOR NOW...AS IT
IS MOST LIKELY TO OCCUR DURING SECOND PERIOD.

A SQUEEZE PLAY BETWEEN THE LOW IN THE GULF...A WEAK RIDGE OVER THE
COASTAL WATERS...AND THE LOW IN THE PLAINS WILL RESULT IN SMALL
CRAFT ADVISORY WINDS AND SEAS STARTING LATE TONIGHT...AND CONTINUING
INTO FRIDAY. EVENING SHIFT HOISTED THE ADVISORY DUE TO THE HIGH
CONFIDENCE FACTOR THAT THEY HAD IN THE EVENT OCCURRING. ADVISORY WILL
BEGIN IN THE EASTERN WATERS TONIGHT...AND BE OVER ALL THE COASTAL
WATERS FOR THURSDAY NIGHT AND FRIDAY...DUE TO THE COMBINATION OF THE
LOW...AND THE PASSAGE OF THE SURFACE FRONT. SEAS WILL BECOME RATHER
ROUGH BY THURSDAY NIGHT WITH WAVES IN EXCESS OF 10 FEET POSSIBLE
OVER THE EASTERN OUTER WATERS. WINDS AND WAVES WILL GRADUALLY RELAX
FRIDAY NIGHT INTO SATURDAY AS HIGH PRESSURE TAKES HOLD. 35

&&

Hazardous Weather Outlook

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF COASTAL WATERS
OF SOUTHEAST LOUISIANA AND SOUTH MISSISSIPPI...SOUTHEAST
LOUISIANA AND SOUTHERN MISSISSIPPI.

.DAY ONE...TODAY AND TONIGHT

A SMALL CRAFT ADVISORY WILL GO INTO EFFECT TONIGHT FOR THE GULF
COASTAL WATERS EAST OF THE MISSISSIPPI RIVER AND OUT 60 NM AS WINDS
INCREASE TO NEAR 20 KNOTS AND SEAS BUILD UP TO 7 FEET.

OTHERWISE...NO HAZARDOUS WEATHER IS EXPECTED THROUGH TONIGHT.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THUNDERSTORMS...
ISOLATED TO SCATTERED THUNDERSTORMS WILL BE POSSIBLE THURSDAY AND
THURSDAY NIGHT A A COLD FRONT MOVES SLOWLY EAST ACROSS THE AREA. A
FEW STRONG STORMS WILL BE POSSIBLE...HOWEVER...SEVERE THUNDERSTORMS
ARE NOT ANTICIPATED.

MARINE...
SMALL CRAFT ADVISORY CONDITIONS WILL PREVAIL ACROSS THE GULF COASTAL
WATERS EAST OF THE MISSISSIPPI RIVER THURSDAY AND FRIDAY...AND WEST
OF THE MISSISSIPPI RIVER THURSDAY NIGHT AND FRIDAY. WINDS OF 20 TO
25 KNOTS AND SEAS OF 7 TO 10 FEET CAN BE EXPECTED DURING THE PERIOD.


New Orleans Local Weather thread - ROLLTIDE - 10-22-2008 11:48 AM

NATIONAL WEATHER SERVICE NEW ORLEANS LA
350 AM CDT WED OCT 22 2008

.DISCUSSION...
DIGGING MID/UPPER LEVEL TROUGH MOVING INTO THE PLAINS WILL EVOLVE
INTO A CLOSED LOW OVER THE CENTRAL/SOUTHERN PLAINS TODAY THAT WILL
MOVE SLOWLY EASTWARD ACROSS THE MID MISSISSIPPI VALLEY THROUGH THE
END OF THE WORK WEEK AND INTO THE EASTERN CONUS OVER THE WEEKEND.
AS THIS FEATURE APPROACHES...MOISTURE WILL BE DRAWN NORTHWARD FROM
THE GULF AND WILL DEEPEN WITH TIME WITH PRECIPITABLE WATER VALUES
FORECAST TO INCREASE TO NEAR 1.75 INCHES TONIGHT INTO THURSDAY.
INSTABILITY WILL BE SOMEWHAT LIMITED...THEREFORE ONLY ISOLATED TO
SCATTERED THUNDERSTORMS WILL BE MIXED IN WITH THE NUMEROUS SHOWERS
EXPECTED THURSDAY INTO THURSDAY NIGHT. THE COLD FRONT ASSOCIATED
WITH THE SYSTEM WILL ADVANCE SLOWLY EAST ACROSS THE FORECAST AREA
THURSDAY WITH AN INVERTED TROUGH OVER THE GULF ALSO BRUSHING THE
AREA. DRIER AIR WILL FILTER INTO THE AREA BEGINNING ON FRIDAY WITH
LEFT SHOWERS ENDING FROM WEST TO EAST. DRY WEATHER WILL BE IN THE
OFFING OVER THE WEEKEND AND INTO NEXT WEEK WITH NORTHWEST FLOW
ALOFT PREVAILING AS THE AFOREMENTIONED SYSTEM MOVES EAST AND A
DEEP TROUGH DEVELOPS OVER THE EASTERN CONUS. SURFACE HIGH PRESSURE
BUILDING INTO THE GULF COAST REGION IN THE WAKE OF THE COLD FRONT
WILL BE REINFORCED EARLY NEXT WEEK.


New Orleans Local Weather thread - ROLLTIDE - 10-23-2008 12:05 AM

NATIONAL WEATHER SERVICE NEW ORLEANS LA
1030 PM CDT WED OCT 22 2008

.UPDATE...
NO CHANGES MADE TO FORECAST PACKAGE AT THIS TIME AS WEATHER
SITUATION APPEARS TO BE MATERIALIZING AS EXPECTED. LARGE
UPPER LEVEL DIVERGENCE PATTERN OVER TEXAS AND WESTERN LOUISIANA TO
TRANSLATE EASTWARD AS LARGE LOW PRESSURE SYSTEM OVER KANSAS MOVES
EAST. RAINFALL COVERAGE HAS BEEN BETTER THAN LATELY THIS EVENING
AND SHOULD CONINUE TO INCREASE THROUGH THURSDAY. ONE OR TWO
LIGHTNING STRIKES NOTED NEAR BOGALUSA IN THE PAST HOUR ALONG WARM
FRONTAL ZONE MOVING NORTH. WEATHER GRIDS INTRODUCE THUNDER AT 06Z
AND THIS LOOKS REASONABLE AS COLUMN CONTINUES TO DESTABILIZE. 00Z
UPPER AIR CHARTS SHOW STRONG BLOCKING HIGH OVER THE GREAT LAKES
AND ALONG THE SPLINE OF THE APPALACHIANS THAT WILL LIKELY RETARD
EASTERLY MOTION OF THE LOW FOR A WHILE LONGER. MEANWHILE...LOW
LEVEL JET NOTED TO BE INCREASING IN INTENSITY OVER OUR FORECAST
AREA...BASED ON SURFACE OBSERVATIONS AND KLIX WSR-88D VAD WIND
PROFILES.

&&

.AVIATION...
/06Z TAFS/
EXPECT MVFR CEILINGS AND VISIBILITIES TO DEVELOP BETWEEN 09-12Z AS
AN AREA OF DEEP UPPER LEVEL LIFT SUPPORTS THE FORMATION OF CLOUDS
AND SHOWERS ACROSS THE REGION. THESE PREVAILING MVFR CONDITIONS MAY BE
PUNCTUATED BY A FEW THUNDERSTORMS AND BRIEF PERIODS OF IFR CEILINGS
AND VISIBILITIES...ESPECIALLY AFTER 18Z...AS A COLD FRONT MOVES
THROUGH THE AREA. INSTABILITY APPEARS FAIRLY LIMITED...BUT EXPECT A
HIGH ENOUGH CHANCE FOR CONVECTION TO GO WITH A TEMPO GROUP FOR THE
THUNDERSTORM ACTIVITY. WINDS WILL INCREASE TOMORROW AS WELL...AS A
LOW IN THE GULF TAKES SHAPE. KMSY WILL BE MOST IMPACTED BY THESE
STRONGER WINDS IN EXCESS OF 12 KNOTS...ESPECIALLY AFTER 18Z.

&&


New Orleans Local Weather thread - dkmac - 10-23-2008 06:51 AM

000
FXUS64 KLIX 231022 CCA
AFDLIX

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE NEW ORLEANS LA
510 AM CDT THU OCT 23 2008

.SYNOPSIS...
STATIONARY DEEP CYCLONE...VERY WELL DEFINED ON WATER VAPOR
IMAGERY OVER THE CENTRAL PLAINS...IS CUT-OFF FROM THE WESTERLIES
WHICH EXTEND WELL TO THE NORTH. THE CORE OF STRONGEST WINDS IN THE
UPPER LEVELS HAS BEEN SHIFTING FROM THE WESTERN QUADRANT TO THE
SOUTHEAST QUADRANT OVER THE LAST SEVERAL HOURS BASED ON RUC
ANALYSIS AND SATELLITE TRENDS. ADDITIONAL DISTURBANCES WERE NOTED
IN THE SUBTROPICAL STREAM ACROSS THE WESTERN AND CENTRAL GULF
COAST REGION. THE FAIRLY STRONG COLD FRONT...NOTED BY A 10 DEGREE
DROP IN TEMPERATURES AND DEWPOINTS...EXTENDED FROM JUST WEST OF
NATCHEZ TO JUST WEST OF LAFAYETTE TO THE EXTREME NORTHWEST GULF OF
MEXICO AT 4 AM. A BROAD AREA OF LOW PRESSURE IS ANALYZED OVER THE
CENTRAL GULF OF MEXICO.

.SHORT TERM...
CYCLONE OVER CENTRAL PLAINS WILL ONLY NUDGE SLIGHTLY EAST LATER
TODAY. HOWEVER...MID/UPPER DIVERGENCE ASSOCIATED WITH WIND MAXES
ROTATING AROUND SOUTHEAST QUADRANT OF LOW WILL SHIFT EAST ACROSS
THE LOWER MISSISSIPPI VALLEY TODAY AS THE COLD FRONT SLOWLY
PUSHES INTO THE FORECAST AREA. BROAD AREA OF LOW PRESSURE OVER THE
CENTRAL GULF OF MEXICO WILL STRENGTHEN SLIGHTLY AS THE COOLER AIR
MEETS UP WITH THE MORE TROPICAL AIRMASS. RADAR TRENDS SUGGEST MOST
CONCENTRATED AREAS OF RAIN AND CONVECTION EARLY THIS MORNING WILL
BE WEST AND NORTH OF BATON ROUGE AND NEAR THE SOUTH CENTRAL/
SOUTHEAST LOUISIANA COAST. THESE MORE CONCENTRATED AREAS OF
RAIN...SHOWERS...AND ISOLATED THUNDERSTORMS WILL BE HARD TO
PREDICT THROUGH THE DAY...SO WILL CONTINUE TO BROAD BRUSH A 70
PERCENT CHANCE OF SHOWERS TODAY. INSTABILITY WILL REMAIN LIMITED
DUE TO CLOUD COVER SOUTHEAST OF THE FRONT...AND COOLER AIR BEHIND
THE FRONT...SO WILL KEEP ONLY A SLIGHT CHANCE OF THUNDERSTORMS
MIXED IN WITH THE RAIN AND SHOWERS TODAY.

THE LOW OVER THE PLAINS WILL GRADUALLY ACCELERATE EAST INTO THE
MISSOURI VALLEY LATE TONIGHT AND THE MID MISSISSIPPI VALLEY BY
LATE FRIDAY. THIS WILL PUSH THE COLD FRONT THEN DRIER AIR THROUGH
THE REMAINDER OF THE FORECAST AREA TONIGHT AND FRIDAY MORNING. LOW
PRESSURE ALONG THE BAROCLINIC ZONE OVER THE NORTHEAST GULF WILL
MOVE ACROSS THE FLORIDA PANHANDLE ON FRIDAY. TEMPERATURES WILL
DROP BACK TO BELOW NORMAL LEVELS WITH LOWER HUMIDITY EXPECTED
FRIDAY AND FRIDAY NIGHT.

.LONG TERM...
A WEAK DISTURBANCE WILL MOVE THROUGH THE FORECAST AREA SATURDAY
AFTERNOON AND EVENING WITH NO ASSOCIATED WEATHER. DRY SURFACE HIGH
PRESSURE WILL PREVAIL OVER THE WEEKEND WITH BELOW NORMAL LOWS...AND
NEAR NORMAL HIGH TEMPERATURES ON SATURDAY WARMING TO ABOVE NORMAL
ON SUNDAY.

AN ARCTIC AIRMASS WILL BE PLUNGING SOUTH INTO THE NORTHERN AND
CENTRAL PLAINS STATES ON SUNDAY AS A DEEP UPPER TROUGH SETS UP
OVER THE EASTERN CONUS MONDAY INTO TUESDAY. A STRONG REINFORCING
COLD FRONT WILL MOVE THROUGH THE FORECAST AREA LATE SUNDAY NIGHT
INTO MONDAY. THERE COULD BE A FEW SPRINKLES OF RAIN WITH THIS
FRONT...BUT WILL NOT CARRY MENTION OF MEASURABLE RAIN. THIS COLD
FRONT WILL USHER EVEN COOLER AIR THAN THE LAST FRONT...AND WOULD
NOT BE SURPRISED TO SEE SOME LOWS DOWN AROUND 40 DEGREES IN THE
COLDER LOCATIONS BY MONDAY NIGHT/TUESDAY MORNING AND POSSIBLY
AGAIN TUESDAY NIGHT/WEDNESDAY MORNING. TEMPERATURES WILL BE BELOW
NORMAL MONDAY THROUGH WEDNESDAY AND POSSIBLY INTO NEXT THURSDAY.
22

&&

.AVIATION...
EXPECT MVFR CEILINGS AND VISIBILITIES TO DEVELOP OVER THE NEXT FEW
HOURS AS BOUNDARY...AND AREA OF SIGNIFICANT PRECIPITATION APPROACH
THE TERMINALS. THESE PREVAILING MVFR CONDITIONS MAY BE PUNCTUATED BY
ISOLATED THUNDERSTORMS AND BRIEF PERIODS OF IFR CEILINGS AND
VISIBILITIES...ESPECIALLY AFTER 18Z...AS A COLD FRONT MOVES THROUGH
THE AREA. INSTABILITY APPEARS FAIRLY LIMITED...BUT EXPECT A HIGH
ENOUGH CHANCE FOR CONVECTION TO GO WITH A TEMPO GROUP FOR THE
THUNDERSTORM ACTIVITY. ANY SIGNIFICANT IMPROVEMENT IN TERMINAL
CONDITIONS MOST LIKELY WILL NOT OCCUR BEFORE 06Z FRIDAY...PROBABLY
CLOSER TO THE 12Z-15Z RANGE FOR KMSY AND KGPT. 35

&&

.MARINE...
FORECAST GOING PRETTY MUCH ACCORDING TO PLAN...WITH EASTERN COASTAL
WATERS NEAR...OR IN ADVISORY CRITERIA. WESTERN AREAS...BEING A
LITTLE FURTHER FROM THE SURFACE LOW...HAVE A LITTLE LESS
GRADIENT...AND WILL CARRY EXERCISE CAUTION IN THAT AREA UNTIL THE
SMALL CRAFT ADVISORY KICKS IN AT MIDDAY. TIDAL LAKES LOOK TO STAY
JUST BELOW HEADLINE CRITERIA THROUGH THE DAY TODAY. MAY NEED AN
EXERCISE CAUTION HEADLINE THERE FOR THE OVERNIGHT HOURS...BUT
FORECAST SURFACE PRESSURE GRADIENT DOESN`T APPEAR STRONG ENOUGH TO
JUSTIFY AN ADVISORY. WITH EASTERLY WINDS NEAR 20 KNOTS OVER THE
COASTAL WATERS EAST OF THE MOUTH OF THE MISSISSIPPI FOR THE NEXT 12
TO 24 HOURS...COULD SEE ENHANCED TIDES EARLY TOMORROW MORNING...BUT
THIS SHOULD ONLY OCCUR FOR ONE TIDE CYCLE...AS WINDS SHOULD BE
OFFSHORE FOR THE HIGH TIDE CYCLE SATURDAY MORNING.

WINDS AND SEAS SHOULD ABATE STARTING LATE FRIDAY AFTERNOON...AND
SHOULD NOT HAVE ANY HEADLINES NECESSARY FOR SATURDAY AND SUNDAY.
REINFORCING SHOT OF COOL AND DRY AIR WILL LIKELY NECESSITATE SMALL
CRAFT ADVISORIES AGAIN ON MONDAY. 35

&&


Hazardous Weather Outlook

614 AM CDT THU OCT 23 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF COASTAL WATERS
OF SOUTHEAST LOUISIANA AND SOUTH MISSISSIPPI...SOUTHEAST
LOUISIANA AND SOUTHERN MISSISSIPPI.

.DAY ONE...TODAY AND TONIGHT

ISOLATED THUNDERSTORMS ARE EXPECTED TODAY AND TONIGHT. THE MAIN
THREAT FROM ANY THUNDERSTORMS TODAY WILL BE OCCASIONAL LIGHTNING
STRIKES AND LOCALLY HEAVY RAINFALL AMOUNTS OF 1 TO 2 INCHES IN A
SHORT PERIOD OF TIME. ONE OR TWO STORMS COULD BECOME STRONG AND
PRODUCE STRONG GUSTY WINDS...AND POSSIBLY AN ISOLATED WATERSPOUT
OVER THE GULF COASTAL WATERS.

CONDITIONS WILL REMAIN HAZARDOUS FOR SMALL CRAFT TODAY AND
TONIGHT ACROSS THE COASTAL WATERS OUT TO 60 NAUTICAL MILES. A
STRONG COLD FRONT AND A DEVELOPING LOW PRESSURE AREA WILL CREATE
WINDS OF 20 KNOTS OR GREATER AND SEAS OF 7 FEET OR HIGHER.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

CONDITIONS WILL REMAIN HAZARDOUS FOR SMALL CRAFT FRIDAY AS LOW
PRESSURE MOVES ACROSS THE NORTHEAST GULF OF MEXICO AND FLORIDA
PANHANDLE.

NO HAZARDOUS WEATHER IS EXPECTED SATURDAY AND SUNDAY.

ANOTHER STRONG COLD FRONT IS EXPECTED TO MOVE ACROSS THE CENTRAL
GULF COAST REGION LATE SUNDAY NIGHT AND MONDAY. THIS WILL CREATE
HAZARDOUS CONDITIONS FOR SMALL CRAFT AGAIN ON MONDAY AND MONDAY
NIGHT. UNSEASONABLY COLD TEMPERATURES ARE EXPECTED EARLY TUESDAY
MORNING AND AGAIN EARLY WEDNESDAY MORNING WITH LOWS IN COLDER
NORTHERN LOCATIONS EXPECTED TO REACH THE UPPER 30S TO AROUND 40
DEGREES.