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New Orleans Local Weather thread - dkmac - 11-19-2008 07:19 AM

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fxus64 klix 191006
afdlix

area forecast discussion
national weather service new orleans la
406 am cst wed nov 19 2008

.discussion...
Latest upper air analysis showed a large trough off the east coast
providing a northwest flow from the central plains to east coast.
In addition...ridge was located over the rockies and a
disturbances over south central canada. Surface map showed a
1030mb high over the central gulf coast. The upper level
disturbance over south central canada will dive southeast and push
an associated surface boundary through the forecast area early
friday morning. This feature will maintain lower than normal temps
friday through sunday. Gfs continues to flip and ecmwf stays on
course...now both are in agreement and have a system moving east
across the northern tier next week and drag an axis across the
forecast area monday night...will insert a chance of rain for this
time. A dry forecast is expected for thanksgiving for now.

&&

.aviation...
/12z taf issuance/
strong surface ridging combined with deep northwest flow aloft
will allow for vfr conditions at all terminals through the
forecast period.

&&

winds and seas will continue to decrease today. Strong surface
ridging will build over the region today and remain in place
through thursday. Light winds and calm seas are expected with this
ridge. A series of fast moving fronts should then slip through on
the back of deep northwesterly flow aloft thursday night into
friday. Gradient flow will increase in the wake of these
fronts...as another cold dome of high pressure advects in over the
weekend. Small craft conditions will likely return friday and
persist through sunday.


New Orleans Local Weather thread - ROLLTIDE - 11-19-2008 05:27 PM

FXUS64 KLIX 192156
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
356 PM CST WED NOV 19 2008

.SHORT TERM...
HIGH PRESSURE OVER THE EASTERN UNITED STATES WAS MODERATING
STEADILY AND FLOW HAS BECOME MARITIME ORIENTED. LOWS SHOULD NOT BE
AS COLD AS PAST NIGHT BUT MAY HAVE SOME STEAM/RADIATIONAL FOG
CONSIDERATIONS IN LOW LYING AREAS AND DOWNWIND FROM WATER BODIES.
A MILD AND DRY THURSDAY BEFORE NEXT CANADIAN SURGE MOVES THROUGH
THURSDAY EVENING...BRINGING THE AREA BACK TO NEAR FREEZING MORNING
TEMPS AWAY FROM COASTAL INFLUENCES AND HIGHS IN THE UPPER 50S
FRIDAY ALONG WITH A COLD BREEZE.

.LONG TERM...
HIGH PRESSURE AREA MOVES TO THE EASTERN SEABOARD AND MODERATES
OVER THE WEEKEND WITH YET ANOTHER CANADIAN SURGE DROPPING INTO THE
CENTRAL UNITED STATES. THIS SYSTEM MAY SHUNT MORE EASTWARD AS THE
UPPER LOW SPLITS...POLAR FLOW OFF WEST COAST RIDGE IN THE NORTH...ZONAL
TO WEAKLY CYCLONIC FLOW IN THE SOUTHERN BRANCH. THIS MAY BE THE
BEST CHANCE OF PRECIPITATION BUT THE BEST LIFT DYNAMICS MAY BE
REMOVED TOO FAR NORTH TO YIELD MUCH ON MONDAY...ESPECIALLY AS THE
UPPER FLOW BECOMES CONFLUENT OVER THE FORECAST AREA. WILL MAINTAIN
CHANCE POPS FOR MONDAY BUT THUNDER MAY BE AT A PREMIUM.

&&


New Orleans Local Weather thread - ROLLTIDE - 11-20-2008 07:59 AM

NATIONAL WEATHER SERVICE NEW ORLEANS LA
349 AM CST THU NOV 20 2008

.DISCUSSION...
LATEST SURFACE ANALYSIS SHOWED A 1009MB LOW OVER EAST PORTIONS OF
THE GREAT LAKES REGION WITH A FRONTAL BOUNDARY EXTENDING SOUTHWEST
THROUGH THE OHIO VALLEY TO THE TEXAS PANHANDLE. A 1047MB HIGH WAS
NOTED OVER SOUTH CENTRAL CANADA AND MONTANA. WATER VAPOR IMAGERY
SHOWED SEVERAL DISTURBANCES FROM THE GREAT LAKES TO THE NORTHERN
PLAINS. SHORT RANGE MODELS HAVE SOMEWHAT PEGGED THE SHALLOWNESS OF
THIS AIRMASS OVER THE NORTH AND CENTRAL PLAINS THIS MORNING. GFS
AND NAM MODEL SOUNDING SHOW THE COLD AIR UNDERCUTTING THE WEST TO
NORTHWEST FLOW OVER THE EAST CONUS THROUGH THE WEEKEND. THE FRONT
SHOULD PUSH THE FORECAST AREA THIS EVENING THROUGH EARLY FRIDAY
MORNING. HAVE INCREASED CLOUD COVER GRID TONIGHT WITH THE
INITIALLY WITH WEST TO NORTHWEST FLOW OVER THE COLD AIR...BUT
DURATION OF CLOUDS SHOULD REMAIN BELOW 9 HOURS. BOUNDARY LAYER WINDS
AFTER THE FRONTAL PASSAGE WILL PUSH THE UP AGAINST WIND ADVISORY
CRITERIA SOUTH OF TIDAL LAKES FRIDAY...BUT SHOULD RELAX A LITTLE
AS THE HIGH SETS UP OVER THE TENNESSEE VALLEY BY FRIDAY NIGHT. THE
THICKNESS LAYERS ARE EXPECTED TO DECREASE...BUT NOT AS MUCH AS
LAST WEEK. WITH HIGH OVER TENNESSEE VALLEY...EAST FLOW MAY NOT GO
COMPLETELY GO CALM FOR INLAND AREA FRIDAY NIGHT. ERGO...WILL NOT
GO AS LOW NAM AND NGM NUMBERS OF BELOW 30F FOR FRIDAY NIGHT.
HOWEVER...A FREEZE IS POSSIBLE AGAIN FOR THE MISSISSIPPI
COAST...SOUTH MISSISSIPPI AND EAST CENTRAL LOUISIANA NORTH OF LAKE
PONTCHARTRAIN...BTR AREA WILL BE CLOSE AGAIN. GFS AND ECMWF ARE IN
AGREEMENT WITH A SHARP TROUGH DEVELOPING OVER UPPER AND MID
MISSISSIPPI VALLEY MONDAY AND AN AXIS ROTATING SOUTHEAST THROUGH
GULF COAST REGION MONDAY NIGHT. INSTABILITY REMAINS
MARGINALLY...SO WILL KEEP A SLIGHT CHANCE FOR THUNDERSTORMS AND A
CHANCE FOR SHOWERS MONDAY AND MONDAY. ANOTHER SYSTEM MAY BRING A
CHANCE OF RAIN ACROSS THE AREA AFTER THANKSGIVING.

&&

.AVIATION...
PATCHY FOG ACROSS THE AREA MAY LEAD TO BRIEF MVFR/IFR VISIBILITIES
THIS MORNING. VRBL WINDS WILL GRADUALLY BECOME WESTERLY AND THEN
N/NW TODAY AND THEN THIS EVENING AS A COLD FRONT SWEEPS THROUGH THE
REGION. WINDS BEHIND THE BOUNDARY WILL INCREASE TO OVER 10 KTS WITH
GUSTS APPROACHING 20 KTS...ESP AT MSY. EXPECT INCREASING LOW TO MID
LEVEL CLOUDS AT TERMINALS BEHIND THE FRONT. VFR CONDITIONS WILL
DOMINATE THROUGH THE PERIOD.


New Orleans Local Weather thread - dkmac - 11-21-2008 06:54 AM

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fxus64 klix 211137
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area forecast discussion
national weather service new orleans la
537 am cst fri nov 21 2008


.aviation...
Cold front is now well offshore and northerly winds behind this
boundary have increased significantly. Gpt and msy have
experienced the strongest winds thus far and should be the case
today with sustained winds 15 to 20 kts and gusts below 30 kts.
Mcb and btr will have winds about 5 kts less. Mid level cloud deck
has almost cleared out and should be gone within the next couple
hrs. Clear skies are expect for the next 24 hrs. Vfr conditions
will prevail through the period at all terminals.

Meffer

&&

.prev discussion... /issued 357 am cst fri nov 21 2008/

discussion...
Latest surface analysis showed a cold front from south georgia to
extreme north central gulf of mexico to texas coastal waters.
North winds of 15 knots with gusts up to 25 knots were noted
across louisiana and central and south mississippi this morning. A
1039mb high was located over the central plains with a ridge axis
southwest to west texas. Upper air analysis showed the main trough
east of hudson and northwest flow over the plains and mississippi
valley. The embedded short waves...responsible for driving the
frontal boundary through the area...were generally over ohio
valley and mid mississippi valley. 1000 to 700mb thickness values
off of gfs are not as low as last week. Gfs initialized values
around 2980m at 00z before the frontal passage. Gfs shows a drop
near 2900m tonight...not as low as last week...but starting point
is much lower. Surface map revealed teens and single digit
dewpoint across northern arkansas and missouri and 20s across
north louisiana and mississippi this morning. Gfs and nam shows
north winds driving this dry air south today. The surface high
expected to slide east over the tennessee valley by saturday
morning. Circulation around the high and pressure gradient of 4mb
across the forecast area will likely prevent winds from becoming
completely calm saturday morning across northern and inland zones.
Dry air will allow air to cool...but light east flow will somewhat
disrupt radiational cooling. North zones will likely experience a
another light freeze and the light freeze may occur in and around
btr. Ergo...will go with a freeze watch for the baton rouge metro
area on saturday morning. Thickness value will rebound and day
time will warm about 6 degrees each day saturday and sunday. Both
gfs and ecmwf continue to show a deepening trough over the
mississippi valley and great lakes monday and driving an axis
through the area monday and monday night...gfs is slightly faster
with clearing precip by tuesday. A slow dry warming trend is
expected as an upper level ridge moves east over the mississippi
valley going into thanksgiving day.

Marine...
The cold front has just about reached the outer waters of the
northern gulf. Wind speeds have been steadily increasing now at
around 20 kts with gusts up to 25 kts. Seas have been responding as
well nearing 4 feet at outer locations. Conditions will continue to
worsen throughout the next several hours and then ease later this
afternoon as the surface pressure gradient weakens. The surface
ridge behind the cold front will progress eastward into the se u.s.
Through the weekend and result in winds becoming more easterly.
Winds will likely remain elevated through this period and may need
small craft exercise caution headline.

Meffer

fire weather...
Very dry air is moving into the region this morning behind a cold
front. Dewpoints in central and northern mississippi have dropped
into the high teens. While some air mass modification will
occur...could see mid 20 td/s in southern ms. With highs expected to
be in the mid to lower 50s...rh/s will decrease to near 25 pct along
the northern and eastern fringe of the cwa. Northerly winds around
15 kts this morning

meffer


New Orleans Local Weather thread - dkmac - 11-22-2008 07:23 AM

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fxus64 klix 221132
afdlix

area forecast discussion
national weather service new orleans la
532 am cst sat nov 22 2008


.aviation...
Light ene winds continuing at sites at just under 10 kts. Biggest
influence on weather will still be surface high pressure ridge
located northeast of the area. As this high slowly shifts
eastward...ne winds will gradually become more easterly around 10
kts. Low to mid level clouds are expected to move into the area
later this afternoon and should see mvfr cigs. Vfr conditions
should dominate through mid afternoon and intermittent mvfr for
the rest of the period. Light winds expected overnight.

Meffer
&&

.prev discussion... /issued 358 am cst sat nov 22 2008/

discussion...

Early this morning there was surface high pressure centered over
the tennessee valley with a stacked low over the northern plains
states. Temps across southern mississippi and east-central
louisiana were in the lower 30s and a light freeze is expected
across this area. As the high pressure shifts to the east through
the weekend...onshore flow will develop across the lower
mississippi valley. This should bring milder temps and increasing
moisture. By monday morning an upper-level trough will be pushing
into the mississippi valley with an associated cold front pushing
into arkansas and east texas. Showers should be moving into
louisiana...with a slight chance for thunderstorms during the day
monday. The better dynamics should remain to the north...thus
the severe weather threat is low. The front is expected to push
through most of the pcwa monday evening. High pressure will settle
into the area for the middle part of the week. Toward the end of
next week and the end of the forecast period there is some
discrepancy between the models and model runs. The 00z gfs shows a
surface low pushing from the plains states toward the north-
central gulf coast and dramatically weakening...whereas older runs
do not weaken the low as much. The ecmwf shows the low remaining
stronger and moving toward the tennessee valley with a cold front
pushing through our pcwa over the weekend. For now will will lean
more toward the earlier gfs solution. 25


marine...
Decided to go ahead and let the small craft advisory in the outer
waters finish out at 12z since seas and winds are very close to
minimum criteria. Small craft will need to use caution along coastal
waters as easterly winds will be in the 15 to 20 kt range today.
Lake areas aren/t expected to be quite as windy. Similar conditions
again on sunday as high pressure continues to keep easterly flow
across the area. Changes will come early next week as a cold front
will sweep through the area monday night. Initially showers and then
isolated thunderstorms will proceed this boundary as se winds bring
in a substantial increase in gulf moisture. Small craft advisory
conditions look like they will return...at least in the outer
coastal waters as brisk north winds increase behind the front. High
pressure will build in behind the front lasting through much of the
week.

Meffer


New Orleans Local Weather thread - dkmac - 11-23-2008 07:42 AM

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area forecast discussion
national weather service new orleans la
623 am cst sun nov 23 2008

.aviation /12z tafs/...
Vfr conditions are expected during the day today with ceilings
generally remaining at or above 8000ft. Btr and mcb may see some
showers move into the area in advance of the cold front late
sunday night/early monday morning. 25

&&

.prev discussion... /issued 428 am cst sun nov 23 2008/

short term...
Southeast winds yesterday afternoon quite an increase in moisture
to the region. Surface dewpoints have reached into the 40s and
water vapor imagery is show a pacific moisture fetch in the mid
levels. Mid level cloud deck may break some today...but should
maintain mostly cloudy skies as high clouds move across the area.
Lack of insolation from cloudcover should keep temps from getting
too high...so decided to go on the lower side of guidance.
Otherwise...few weather changes expected today aside from
dewpoints rising into the upper 50/s as southeast winds persist.

Long term...
Next upper trough expected to impact the region is currently
track over the northern rockies. This system will progress ese
across the conus through early this week...sending a cold front
through. This front should be more pacific in nature compared to
previous front. Rainfall proceeding this boundary is expected on
monday. Nam and gfs bufr forecast soundings indicating that the
column will continue to moisten reaching around 1.5 inches by mid
day monday. Instability looks to be on the marginal side with li/s
barely negative and little pos buoy energy over the cwa.
So...severe potential appears to be minimal if any. Initially
rainfall should be all showers beginning late sunday night mainly
west of baton rouge. Showers will increase in coverage and
intensity through the day on monday. Isolated thunderstorms will
also be possible...but likely only in the afternoon. Total
rainfall amounts look to be around one half an inch for the day.
Models in fair agreement on rainfall with nam as the outlier
having a later initiation. The front will push through monday
evening around 00z and clear out all precip.

Surface high pressure will build in behind the front on tuesday
and wednesday. Temperatures will only drop to a few degrees below
normal. Considerable drying is expected for through mid week but
the return of onshore flow by thurs afternoon should bring
abundant moisture back to the region.

The next system into this coming weekend will bring the next
chance for rainfall. Pattern shows a surface low developing and
tracking across central louisiana. Will have to monitor for the
potential of fall severe weather setup as instability and shear
look to be conducive for strong storms. Confidence isn/t very high
attm due to possible model changes between now and then.

Meffer

marine... The seas have diminished over the outer waters...so the
exercise caution has been dropped. Winds are expected to pick up
again to 15 to 20 knots ahead of the frontal passage sunday night
and again monday night/tuesday morning after frontal passage.
Currently it looks like the conditions will remain just below
small craft advisory criteria behind the cold front. 25


New Orleans Local Weather thread - dkmac - 11-24-2008 07:34 AM

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fxus64 klix 241204
afdlix

area forecast discussion
national weather service new orleans la
604 am cst mon nov 24 2008

.aviation...

Mvfr conditions are expected to develop as showers move into the
area today ahead of the cold frontal passage this afternoon/evening.
The best chances for thunderstorms will be during the afternoon
hours. Clearing is expected tonight with light winds at
mcb...btr...gpt. Winds may stay up around 10 knots off the lake at
msy. 25


&&

.prev discussion... /issued 409 am cst mon nov 24 2008/

short term...
Strong dynamic cold front will move through the region today.
Strong ts should errupt across arkansas into kentucky while a distinct
line of sh/ts will begin to develop from the gulf into the upper
tx coast leading into the area of severe ts over ark. The weaker
line of sh/ts should evolve through the morning as some strong mid
and upper support begins to swing down into the area by late
morning. There will still be the possibility of an isolated strong
or severe ts for most areas but the best areas for a severe ts to
occur will be found is from baton rouge to gulfport. This is where
an abundance of deep moisture and heating will be advected
inland...not from sunlight but from the gulf. This should help
things get goind over the southern half of the area this morning.
Elsewhere there will still be room for an isolated strong or
severe but areas north of the line will nee some heating to get a
primed atmos. Areas well north of ours will have plenty of dynamic
lift and will need little heating to get things started. Will
mention the area of best chance of seeing any strong or severe ts
but will simply go with sligth risk for all locations.

Strong caa and daa will be met with a quick return flow within
about 36 hours sending us through a roller coaster ride of temps.
The next front will move in by the end of the week. A sfc low is
expected to develop along the southern end causing the system to
slow somewhat before kicking out sat morning.

Long term...
Some fast moving clipper type systems look to move through the
central part of the country by the start of next week with no real
affect on our weather until mid week.

Marine...
Generally moderate onshore flow will continue until frontal passage
monday evening. A small craft advisory is likely to be required in
the gulf coastal waters as winds rise to 20 to 25 knots...and may be
required in lakes pontchartrain and maurepas as winds approach 20
knots. Winds should subside and begin to become onshore again
midweek...with in increase in winds on friday ahead of the next
frontal system. 25


New Orleans Local Weather thread - dkmac - 11-25-2008 07:52 AM

000
fxus64 klix 251230
afdlix

area forecast discussion
national weather service new orleans la
630 am cst tue nov 25 2008

.aviation /12z tafs/...
Vfr conditions will prevail today at msy...btr...gpt...mcb behind
the cold frontal passage. Winds northerly winds will diminish today
across the terminals. Some light fog is possible around mcb
wednesday morning. 25

.prev discussion... /issued 327 am cst tue nov 25 2008/

short term...
Dry cool air settling across the area this morning. This will have
a temporary stay as warm moist air over the southern gulf makes
its way back along the tx coast and into the la parishes by wed
causing temps to quickly rebound. This will all be in advance of
the next canadian cold front bringing some cold air for the
weekend.

Long term...
A large thermal gradient will set up near shore of the la
coastline by sat causing a sfc low to develop along the old
frontal boundary. This will help throw a lot of moisture back
across the front to the north keeping a deep blanket of clouds and
some rain chances across the area for the weekend. Sunlight
blocked by the cloudiness will help keep temps fairly stable and
cold over the area making it feel like winter in the deep south
into monday morning.

Marine...
Sca conditions to persist through noon today. Advisories are
expected to drop by afternoon as winds fall back to around 15
knots. The next marine weather issues will come with the next cold
front over the weekend.


New Orleans Local Weather thread - ROLLTIDE - 11-25-2008 03:30 PM

000
FXUS64 KLIX 251622 AAA
AFDLIX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1022 AM CST TUE NOV 25 2008

.AVIATION.../18Z TAFS/
HIGH PRESSURE WILL MAINTAIN CLEAR SKIES AND UNRESTRICTED
VISIBILITIES THROUGH 18Z WEDNESDAY. THE EXCEPTION MAY BE A BRIEF
PERIOD OF LIGHT BR/HZ AT KMCB AROUND 12Z. NORTH TO NORTHEAST
WINDS HAVE DIMINISHED...AND WILL NOW STAY GENERALLY LESS THAN 10
KNOTS THROUGH THE PERIOD.

&&

.MARINE.../UPDATE/
WINDS AND SEAS HAVE FALLEN BELOW SMALL CRAFT CRITERIA...BUT HAVE
KEPT /SMALL CRAFT EXERCISE CAUTION/ STATEMENT FOR OUTER WATERS
THROUGH NOON. HIGH PRESSURE WILL CONTINUE TO BUILD AND BECOME
CENTERED OVER THE CENTRAL GULF COAST REGION THIS EVENING WHICH
WILL RESULT IN A CONTINUED EASING OF WINDS AND SEAS THIS AFTERNOON
AND TONIGHT. 22

&&

PREV DISCUSSION... /ISSUED 327 AM CST TUE NOV 25 2008/

SHORT TERM...
DRY COOL AIR SETTLING ACROSS THE AREA THIS MORNING. THIS WILL HAVE
A TEMPORARY STAY AS WARM MOIST AIR OVER THE SOUTHERN GULF MAKES
ITS WAY BACK ALONG THE TX COAST AND INTO THE LA PARISHES BY WED
CAUSING TEMPS TO QUICKLY REBOUND. THIS WILL ALL BE IN ADVANCE OF
THE NEXT CANADIAN COLD FRONT BRINGING SOME COLD AIR FOR THE
WEEKEND.

LONG TERM...
A LARGE THERMAL GRADIENT WILL SET UP NEAR SHORE OF THE LA
COASTLINE BY SAT CAUSING A SFC LOW TO DEVELOP ALONG THE OLD
FRONTAL BOUNDARY. THIS WILL HELP THROW A LOT OF MOISTURE BACK
ACROSS THE FRONT TO THE NORTH KEEPING A DEEP BLANKET OF CLOUDS AND
SOME RAIN CHANCES ACROSS THE AREA FOR THE WEEKEND. SUNLIGHT
BLOCKED BY THE CLOUDINESS WILL HELP KEEP TEMPS FAIRLY STABLE AND
COLD OVER THE AREA MAKING IT FEEL LIKE WINTER IN THE DEEP SOUTH
INTO MONDAY MORNING.

MARINE...
SCA CONDITIONS TO PERSIST THROUGH NOON TODAY. ADVISORIES ARE
EXPECTED TO DROP BY AFTERNOON AS WINDS FALL BACK TO AROUND 15
KNOTS. THE NEXT MARINE WEATHER ISSUES WILL COME WITH THE NEXT COLD
FRONT OVER THE WEEKEND.


New Orleans Local Weather thread - dkmac - 11-26-2008 06:12 AM

000
fxus64 klix 261013
afdlix

area forecast discussion
national weather service new orleans la
413 am cst wed nov 26 2008

.short term...
Short term uncertainty will be on fog for tonight. Will leave grid
sections free of fog development at this time but this may need to
be updated depending on how much moisture is able to return to the
area today. Clouds will also begin to increase along with rain
chances over the next 36 hours.

A slow moving cold front will then enter the area during the day
friday. Timing on this front is up for debate since the cold air
behind it will be moving like malassess. Also a sfc low will be
forming along the boudary as it moves into the area. Will try to
move the front through by late friday night into sat morning.
Cloudy weather will put a lid on any strong heating sat
keeping things cool all day. Sunday and monday we should see some
clearing for a short time before clouds begin to flow back into
the area as a strong sfc low develops along the old boundary over
the western gulf and moves ne. Weather clears up by mid week after
the low exits.

&&

.aviation...
Some light fog will be possible for a short duration this morning
at a few terminals but vis should stay above 2sm. Fog may become
more of a problem thu morning depending on cloud cover and
moisture return. Ceilings will begin to lower by thu as well but
vfr should still exist through the day.

&&

.marine...
No flags.