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New Orleans Local Weather thread - ROLLTIDE - 01-05-2009 08:37 AM

000
FXUS64 KLIX 051303 AAA
AFDLIX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NEW ORLEANS LA
703 AM CST MON JAN 5 2009

.UPDATE...
AFTER MONITORING RADAR TRENDS AND REVIEWING 12Z SOUNDING
DATA...THOUGHT A FLASH FLOOD WATCH WOULD BE PRUDENT FOR TODAY
PRIMARILY FOR THE SOUTH SHORE PARISHES ONLY AT THIS TIME. THE
STORM THAT WAS OVER TERREBONNE PARISH EARLIER WAS PRODUCING RATES
OF 3 INCHES PER HOUR FOR A SHORT DURATION. PRECIPITATION
CALCULATOR AMOUNTS FROM A 324K LIFT AT SURFACE YIELDS 3.80 INCHES
WHICH MAY HAVE ALREADY VERIFIED IN TERREBONNE PARISH. MSAS SURFACE
DATA LOOP SHOWS THETA-E RIDGE VALUED AT 324K FEEDING INTO THIS
REGION FROM THE NEAR GULF WATERS. HAVE CONCERNS ABOUT THE SLOW DRIFT
OF THE RAIN AREA TOWARDS THE METRO AREAS WITH TRAIN ECHO TYPE
CHARACTERISTICS AND A COLUMN THAT WILL BE GETTING MOISTURE RICH IN
TIME AS THE SUB- TROPICAL JET BECOMES BETTER ORIENTED OVER THE
AREA. WILL INDICATE 2-4 INCH ACCUMULATIONS THROUGH THIS AFTERNOON
WHICH DOES EXCEED FLASH FLOOD GUIDANCE ACROSS THE LOWER PARISHES
DUE TO WET SATURDAY OUTCOME. UPDATE AND WATCH OUT MOMENTARILY.
24/RR


New Orleans Local Weather thread - ROLLTIDE - 01-05-2009 09:40 AM

Watching the big easy now for flooding
radar data provided by http://www.allisonhouse.com/
[Image: klix_br248.png]


New Orleans Local Weather thread - ROLLTIDE - 01-05-2009 11:10 PM

000
FXUS64 KLIX 060326
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
926 PM CST MON JAN 5 2009

.MARINE...
HAVE EXTENDED EXERCISE CAUTION HEADLINES OVER COASTAL WATERS
THROUGH 18Z TUESDAY. NEW 00Z NAM SHOWS PRESSURE GRADIENT NOT AS
STRONG AS PREVIOUSLY FORECAST ACROSS OUR AREA THROUGH 00Z
WEDNESDAY. MAY EVEN BE SOMEWHAT OF A LULL DURING THE AFTERNOON
TUESDAY AS FRONTAL BOUNDARY OOZES SLOWLY EASTWARD. EXPECT WE WILL
GET INTO SMALL CRAFT ADVISORY CONDITIONS ABOUT 24 HOURS FROM NOW.
NAM SOLUTION SHOWS STRONGEST WINDS WILL ACTUALLY HOLD OFF UNTIL
WEDNESDAY MORNING.

TIDAL LAKES WILL LIKELY BE BORDERLINE FOR EXERCISE CAUTION FOR A
FEW HOURS AROUND MIDDAY...BUT WILL GIVE MID SHIFT ANOTHER LOOK AT
IT AS WINDS ARE ONLY 10-12 KNOTS OVER THE LAKE RIGHT NOW. 35
&&

.PREV DISCUSSION... /ISSUED 332 PM CST MON JAN 5 2009/

SHORT TERM...
WEAK AREA OF LOW PRESSURE DEVELOPING ALONG THE CENTRAL LOUISIANA
COASTAL PLAIN. WEAK STATIONARY FRONT APPEARS TO BE DRIFTING NORTH
AND EXTENDS FROM THE LOW PRESSURE AREA EASTWARD INTO THE FLORIDA
PARISHES. TEMPERATURES HAVE RISEN TO THE MID 70S TO THE SOUTH OF
THE FRONT WHILE TO THE NORTH WIDELY SCATTERED SHOWERS AND THICK
LOW CLOUDS HAVE KEPT TEMPERATURES TO 60 DEGREES OR LESS. WITH
UPPER LEVEL TROUGH SO FAR TO THE WEST TONIGHT AND LOW LEVEL SOUTH
FLOW...EXPECT MORE FOG TO DEVELOP TONIGHT. SO A DENSE FOG ADVISORY
MAY BE NEEDED LATER TONIGHT FOR BOTH LAND AND MARINE AREAS.

LONG TERM...
FULL LATITUDE 500 MB TROUGH DEVELOPS IN THE SOUTHERN ROCKIES
OVERNIGHT IN RESPONSE TO DIGGING JET COMING OUT OF THE PACIFIC
NORTHWEST. THIS WILL CAUSE SOUTHWEST JET EXTENDING FROM TEXAS BIG
BEND TO THE ARLATX TO STRENGTHEN OVER NIGHT AND INTO TUESDAY. LOW
AND MID LEVEL FLOW SHOULD RESPOND TO THIS SCENARIO AS LOUISIANA COMES
UNDER THE INFLUENCE OF THE RIGHT REAR QUADRANT OF A 130 KNOT 300
MB JET ON TUESDAY.

MEANWHILE A SLOW MOVING COLD FRONT WILL BE APPROACHING SOUTHEAST
LOUISIANA AND SOUTHERN MISSISSIPPI DURING THE DAY AND SHOULD PASS
THROUGH THE COUNTY WARNING AREA BY WEDNESDAY EVENING.

DUE TO THE SLOW MOVEMENT OF THE COLD FRONT AND STRONG UPPER LEVEL
DIVERGENCE ASSOCIATED WITH THE 300 MB JET...HAVE CONTINUED WITH
THREAT OF HEAVY RAIN ASSOCIATED WITH NUMEROUS THUNDERSTORMS.
NUMEROUS SHOWERS AND EMBEDDED THUNDERSTORMS WILL CONTINUE THROUGH
MOST OF TUESDAY EVENING UNTIL THE UPPER LEVEL TROUGH AND 300 MB
JET MOVES EAST OF THE LOWER MISSISSIPPI VALLEY. EXPECT 2 TO 3
INCHES OF RAINFALL ACROSS THE AREA MAINLY TUESDAY AND TUESDAY
EVENING. THIS IS JUST BELOW FLASH FLOOD GUIDANCE...SO HAVE ELECTED
NOT TO ISSUE A FLASH FLOOD WATCH AT THIS TIME...BUT HAVE LEFT THE
DOOR OPEN FOR ONE LATER TONIGHT.


New Orleans Local Weather thread - ROLLTIDE - 01-05-2009 11:12 PM

Hazardous Weather Outlook

000FLUS44 KLIX 052346HWOLIXHAZARDOUS WEATHER OUTLOOKNATIONAL WEATHER SERVICE NEW ORLEANS LA546 PM CST MON JAN 5 2009GMZ530-550-555-570-575-LAZ034>040-046>050-056>070-MSZ068>071-077-080>082-061300-LAKE PONTCHARTRAIN AND LAKE MAUREPAS-COASTAL WATERS FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVERTO LOWER ATCHAFALAYA RIVER LA OUT 20 NM-COASTAL WATERS FROM PASCAGOULA MS TO THE SOUTHWEST PASS OF THEMISSISSIPPI RIVER OUT 20 NM-COASTAL WATERS FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVERTO LOWER ATCHAFALAYA RIVER LA FROM 20 TO 60 NM-COASTAL WATERS FROM PASCAGOULA MS TO THE SOUTHWEST PASS OF THEMISSISSIPPI RIVER FROM 20 TO 60 NM-POINTE COUPEE-WEST FELICIANA-EAST FELICIANA-ST. HELENA-TANGIPAHOA-WASHINGTON-ST. TAMMANY-IBERVILLE-WEST BATON ROUGE-EAST BATON ROUGE-ASCENSION-LIVINGSTON-ASSUMPTION-ST. JAMES-ST. JOHN THE BAPTIST-UPPER LAFOURCHE-ST. CHARLES-UPPER JEFFERSON-ORLEANS-UPPER PLAQUEMINES-UPPER ST. BERNARD-UPPER TERREBONNE-LOWER TERREBONNE-LOWER LAFOURCHE-LOWER JEFFERSON-LOWER PLAQUEMINES-LOWER ST. BERNARD-WILKINSON-AMITE-PIKE-WALTHALL-PEARL RIVER-HAN****-HARRISON-JACKSON-546 PM CST MON JAN 5 2009THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF COASTAL WATERSOF SOUTHEAST LOUISIANA AND SOUTH MISSISSIPPI...SOUTHEASTLOUISIANA AND SOUTHERN MISSISSIPPI..DAY ONE...TONIGHTISOLATED THUNDERSTORMS ARE POSSIBLE LATER THIS EVENING. ANINCREASE IN COVERAGE AND INTENSITY IS LIKELY AFTER MIDNIGHT. ASTRONG UPPER LEVEL TROUGH AND AN APPROACHING COLD FRONTMAY YIELD STRONG THUNDERSTORMS WITH WIND GUSTS UP TO 40 MILES ANHOUR. THE GREATEST THREAT AREA IS NORTH OF INTERSTATES 10 AND 12AND TO THE WEST OF INTERSTATE 55...MAINLY EAST CENTRAL LOUISIANAINCLUDING THE BATON ROUGE METRO AREA AND EXTREME SOUTHWEST MISSISSIPPI.ELSEWHERE AND ESPECIALLY NEAR THE COAST AND TIDAL LAKES...SEA FOGCOULD FORM THIS EVENING. THE FOG COULD BECOME MORE WIDESPREADOVERNIGHT. MOTORISTS SHOULD PROCEED WITH CAUTION DURING THEEVENING AND NIGHT TIME HOURS..DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAYTHERE IS A SLIGHT CHANCE OF SEVERE THUNDERSTORMS TUESDAY AS ASTRONG UPPER LEVEL TROUGH ADVANCES EAST ACROSS THE LOWER MISSISSIPPIVALLEY TUESDAY AFTERNOON AND TUESDAY NIGHT. THE PRIMARY THREATWILL BE DAMAGING WINDS AND VERY HEAVY RAINFALL.SMALL CRAFT ADVISORIES WILL LIKELY BE POSTED FOR STRONGSOUTHWEST WINDS TUESDAY IN ADVANCE OF A COLD FRONT. AFTER THEFRONTAL PASSAGE...STRONG WEST TO NORTHWEST WINDS WILL CONTINUESMALL CRAFT ADVISORIES ON THE COASTAL WATERS TUESDAY NIGHT THROUGHWEDNESDAY. SEAS WILL BE BUILDING 8 TO 10 FEET WELL OFFSHORETUESDAY NIGHT AND WEDNESDAY.WEATHER HAZARDS ARE NOT EXPECTED THURSDAY AND FRIDAY.THUNDERSTORMS ARE EXPECTED SATURDAY IN ADVANCE OF THE NEXT STRONGCOLD FRONT..SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT.HOWEVER...STORM SPOTTER AND EMERGENCY MANAGEMENT ACTIVATION MAYBE REQUIRED ON TUESDAY.


New Orleans Local Weather thread - dkmac - 01-06-2009 06:52 AM

000
fxus64 klix 061003
afdlix

area forecast discussion
national weather service new orleans la
403 am cst tue jan 6 2009

.short term...
Forecast area remains bisected by stationary frontolytic boundary
that undulates between kmcb and kbtr this morning. Balmy
conditions with mid 60s dewpoints reside to the east of the
boundary with lower 50s dewpoints to the west. Spc maintains a
slight risk of severe storms in the warm sector today but marine
layer influences may dampen things a bit. A few conditions do bear
watching...namely the development of a very strong low level jet
this afternoon along with large scale lift provided by 150+ kt jet
streak that slides east in time...placing the forecast area fairly
close to right rear quadrant dynamics while the upper level trough
continues to amplify. Will hit severe risk in hwo but had a lower
confidence to hit it hard in the zone forecast. Local chap output
also shows strong but sub-severe on all point location model
soundings probably in deference to precipitation loading. With
temperatures warming to near record highs in compressional heating
a few storms may have the ability to approach severe...especially
when coupled with high speed sheer later today though directional
sheer may be limited. Near and west of boundary...temperatures
will be tricky and highly dependent on proximity to frontal
zone...which may nudge northwest briefly before attaining cold
frontogenesis and forword progression once the upper level support
arrives from the west.

Liked the gfs idea of drying things rather abruptly from west to
east prior to 12z wednesday so tried to reflect a sharp probability
gradient overnight after midnight tonight. /24

.long term...
Pattern transitions from deep troughing aloft to a more zonal then
southwesterly...somewhat anticyclonic...flow from thursday onward.
At the surface...the next canadian airmass appears to move through
the area saturday evening with sunday and monday being a couple of cool
days...possibly with some overrunning precipitation moving into
the area monday. /24

&&

.aviation...
Visibilities much better this morning compared to yesterday except at
gpt which has been at 1/4sm for several hours. An area of showers
between msy and btr will continue to track northeastward. Rain
coverage is expected to increase throughout the day with a line of
thunderstorms pushing through this afternoon. A few storms could be
strong with heavy rainfall...gusty winds and frequent lightning.
Clearing behind the cold front likely wont occur until late in the
period. S/sw winds will increase today and gradually veer to
northwest. /meffer

&&

.marine...
Sfc trough currently over texas panhandle will track sewd across tx
and then shift nwwd through arkansas. Ongoing southerly winds around
15kts will continue today and likely approach 20kts as gradient
tightens from approaching trough. Thus small craft exercise caution
was continued through 00z for all coastal waters and added the tidal
lakes. Strong thunderstorms will be possible along and ahead of a
cold front that will move through this evening. Heavy rainfall and
gusty winds can be expected with the stronger storms. Sw winds will
then increase to 20 to 25 kts behind the front. Have issued small
craft advisory for all coastal waters from 00z tonight through 00z
thurs. Seas will likely build to 6 to 8 feet. Sfc high pressure will
quickly move into the area wed night and winds should drop off
quickly after sunset. Light winds will persist through the remainder
of the week. Onshore flow will return friday afternoon. Another cold
front will approach the area late this weekend. Uncertainty exists
on whether this front will stall or just push through. /meffer


New Orleans Local Weather thread - ROLLTIDE - 01-06-2009 08:09 AM

FXUS64 KLIX 061003
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
403 AM CST TUE JAN 6 2009

.SHORT TERM...
FORECAST AREA REMAINS BISECTED BY STATIONARY FRONTOLYTIC BOUNDARY
THAT UNDULATES BETWEEN KMCB AND KBTR THIS MORNING. BALMY
CONDITIONS WITH MID 60S DEWPOINTS RESIDE TO THE EAST OF THE
BOUNDARY WITH LOWER 50S DEWPOINTS TO THE WEST. SPC MAINTAINS A
SLIGHT RISK OF SEVERE STORMS IN THE WARM SECTOR TODAY BUT MARINE
LAYER INFLUENCES MAY DAMPEN THINGS A BIT. A FEW CONDITIONS DO BEAR
WATCHING...NAMELY THE DEVELOPMENT OF A VERY STRONG LOW LEVEL JET
THIS AFTERNOON ALONG WITH LARGE SCALE LIFT PROVIDED BY 150+ KT JET
STREAK THAT SLIDES EAST IN TIME...PLACING THE FORECAST AREA FAIRLY
CLOSE TO RIGHT REAR QUADRANT DYNAMICS WHILE THE UPPER LEVEL TROUGH
CONTINUES TO AMPLIFY. WILL HIT SEVERE RISK IN HWO BUT HAD A LOWER
CONFIDENCE TO HIT IT HARD IN THE ZONE FORECAST. LOCAL CHAP OUTPUT
ALSO SHOWS STRONG BUT SUB-SEVERE ON ALL POINT LOCATION MODEL
SOUNDINGS PROBABLY IN DEFERENCE TO PRECIPITATION LOADING. WITH
TEMPERATURES WARMING TO NEAR RECORD HIGHS IN COMPRESSIONAL HEATING
A FEW STORMS MAY HAVE THE ABILITY TO APPROACH SEVERE...ESPECIALLY
WHEN COUPLED WITH HIGH SPEED SHEER LATER TODAY THOUGH DIRECTIONAL
SHEER MAY BE LIMITED. NEAR AND WEST OF BOUNDARY...TEMPERATURES
WILL BE TRICKY AND HIGHLY DEPENDENT ON PROXIMITY TO FRONTAL
ZONE...WHICH MAY NUDGE NORTHWEST BRIEFLY BEFORE ATTAINING COLD
FRONTOGENESIS AND FORWORD PROGRESSION ONCE THE UPPER LEVEL SUPPORT
ARRIVES FROM THE WEST.

LIKED THE GFS IDEA OF DRYING THINGS RATHER ABRUPTLY FROM WEST TO
EAST PRIOR TO 12Z WEDNESDAY SO TRIED TO REFLECT A SHARP PROBABILITY
GRADIENT OVERNIGHT AFTER MIDNIGHT TONIGHT. /24

.LONG TERM...
PATTERN TRANSITIONS FROM DEEP TROUGHING ALOFT TO A MORE ZONAL THEN
SOUTHWESTERLY...SOMEWHAT ANTICYCLONIC...FLOW FROM THURSDAY ONWARD.
AT THE SURFACE...THE NEXT CANADIAN AIRMASS APPEARS TO MOVE THROUGH
THE AREA SATURDAY EVENING WITH SUNDAY AND MONDAY BEING A COUPLE OF COOL
DAYS...POSSIBLY WITH SOME OVERRUNNING PRECIPITATION MOVING INTO
THE AREA MONDAY. /24

&&


New Orleans Local Weather thread - dkmac - 01-06-2009 09:38 AM

hazardous weather outlook
national weather service new orleans la
612 am cst tue jan 6 2009

gmz530-550-555-570-575-laz034>040-046>050-056>070-msz068>071-077-
080>082-061800-
lake pontchartrain and lake maurepas-
coastal waters from the southwest pass of the mississippi river
to lower atchafalaya river la out 20 nm-
coastal waters from pascagoula ms to the southwest pass of the
mississippi river out 20 nm-
coastal waters from the southwest pass of the mississippi river
to lower atchafalaya river la from 20 to 60 nm-
coastal waters from pascagoula ms to the southwest pass of the
mississippi river from 20 to 60 nm-pointe coupee-west feliciana-
east feliciana-st. Helena-tangipahoa-washington-st. Tammany-
iberville-west baton rouge-east baton rouge-ascension-livingston-
assumption-st. James-st. John the baptist-upper lafourche-
st. Charles-upper jefferson-orleans-upper plaquemines-
upper st. Bernard-upper terrebonne-lower terrebonne-
lower lafourche-lower jefferson-lower plaquemines-
lower st. Bernard-wilkinson-amite-pike-walthall-pearl river-
han****-harrison-jackson-
612 am cst tue jan 6 2009

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

thunderstorms...
There is a slight risk of severe thundestorms today as a strong
upper storm system approaches the region and activates a
stationary frontal boundary situated over the outlook area. The
greatest risk will likely be damaging winds from the strongest
storms. An isolated tornado can not be ruled out. Storms today
will also produce frequent lightning and brief heavy rainfall.

Winds...
A strong low level jet is expected to develop during the day with
southwest winds becoming strong and gusty this afternoon before
shifting west this evening. A small craft advisory is in effect
this afternoon for the coastal waters due to developing strong
southwest winds.

.days two through seven...wednesday through monday

strong west to northwest winds are expected wednesday. Due to very
dry and extremely strong winds aloft...localized high gusts in
clear air may occur near the surface. There could be a brief
period between noon and sunset when a gust or two may be in the 40
to 50 mph range.

A small craft advisory will be in effect wednesday for the coastal
waters.

No weather hazards are expected thursday through monday.


New Orleans Local Weather thread - dkmac - 01-07-2009 07:03 AM

000
fxus64 klix 070914
afdlix

area forecast discussion
national weather service new orleans la
314 am cst wed jan 7 2009

.short term...
Surface cold front has moved well east of the forecast area with
the upper level sharp trough axis currently advancing from east
texas. A large high valued vorticity lobe is expected to move in
conjunction with this trough feature to provide a period of
gustiness this morning before falling off significantly after
noon. Indications of this feature are appearing with 3 hour
pressure changes of -3 to -4 mb over texas and west louisiana at
08z in response to sharp height falls aloft. Otherwise...
Temperatures should warm into the lower 60s today...40s tonight
and around 70 thursday with no rain chances. /24

.long term...
Westerly winds expected to bring a moderating temperature trend as
flow becomes zonal aloft. Will maintain zero rain chances friday
and show 20-30 percent friday night as clipper system pushes cold
front through area early saturday. Gfs is hitting on arctic
airmass poised in canadian rockies that is expected to move into
central part of the country middle of next week to bring a threat
of freezing temperatures into the deep south next wednesday night.
/24

&&

.aviation...
Cold front has completely push through the area with all showers
well offshore. Clear skies for the entire period. Westerly winds are
expected to remain light at less than 10 kts throughout the day.
Near calm conditions are possible overnight. Vfr will prevail
through the period at all terminals. /meffer

&&

.marine...
The cold front has pushed through the coastal waters with just a few
lingering showers in the outer coastals. Sw winds of 15 to 20 knots
can be expected today. These winds will gradually subside through
the day and surface high pressure moves into the region. Seas have
been running around 8 feet in the outer waters. Scy will drop off in
the tidal lakes and near shore coastals by 18z as winds decrease
earlier than outer. A lag in the drop in seas is also expected in
the outer coastal waters and thus kept the scy through 00z thurs.
Light winds with little wave action through the rest of the week. A
cold front will push through the area this weekend. /meffer


New Orleans Local Weather thread - ROLLTIDE - 01-07-2009 10:06 PM

NATIONAL WEATHER SERVICE NEW ORLEANS LA
336 PM CST WED JAN 7 2009

.DISCUSSION...
TRANQUIL WEATHER WILL PREVAIL THROUGH THE END OF THE WORK WEEK AS
THE EASTERN CONUS UPPER TROUGH SHIFTS EAST INTO THE ATLANTIC AND A
MORE ZONAL FLOW PATTERN EVOLVES OVER THE SOUTHERN UNTIED STATES.
AT THE SURFACE...HIGH PRESSURE WILL GRADUALLY SLIDE EAST ALLOWING
SOUTHERLY FLOW TO DEVELOP OVER THE FORECAST AREA BY FRIDAY WITH
TEMPERATURES MODERATING IN RESPONSE. THE NEXT SIGNIFICANT WEATHER
FOR THE AREA WILL COME SATURDAY IN THE FORM OF SCATTERED SHOWERS
AS A MID/UPPER TROUGH MOVES FROM THE CENTRAL TO THE EASTERN CONUS
OVER THE WEEKEND PUSHING A COLD FRONT ACROSS THE FORECAST AREA
SATURDAY AFTERNOON. COLDER AIR IN THE WAKE OF THIS FRONT WILL DROP
TEMPERATURES DOWN TO BELOW NORMAL READINGS FOR THE LAST HALF OF
THE WEEKEND AND INTO NEXT WEEK. A DEEP UPPER TROUGH IS FORECAST TO
BE CARVED OUT OVER THE EASTERN CONUS EARLY NEXT WEEK WHICH WILL
ALLOW REINFORCING SHOTS OF COLD AIR TO FILTER INTO THE SOUTHERN
STATES. THE GFS SOLUTION IS SIGNIFICANTLY COLDER THAN THAT OF THE
ECMWF BY THE MIDDLE OF NEXT WEEK OF THE EASTERN U.S.

&&

.AVIATION...
A BROAD RIDGE OF HIGH PRESSURE WILL BUILD INTO THE AREA TONIGHT.
VFR CONDITIONS ARE EXPECTED AT ALL TERMINALS AS STRONG SUBSIDENCE
AND DRY AIR ALLOW FOR CLEAR SKIES. 32

&&

.MARINE...
SURFACE RIDGING WILL BECOME CENTERED OVER THE COASTAL WATERS
TONIGHT...ALLOWING FOR WESTERLY FLOW OF 10 TO 15 KNOTS. WINDS WILL
INCREASE INTO EXERCISE CAUTION RANGE TOMORROW...AS THE PRESSURE
GRADIENT TIGHTENS UP A BIT DUE TO A LOW PASSING NORTH OF THE
REGION. HOWEVER...WINDS WILL QUICKLY DIE OFF BY TOMORROW
EVENING...AS THE GRADIENT WEAKENS. SMALL CRAFT CONDITIONS MAY
REDEVELOP GOING INTO SATURDAY NIGHT IN THE WAKE OF ANOTHER FRONTAL
PASSAGE. HOWEVER...THESE CONDITIONS WILL BE SHORT LIVED...AS
SURFACE RIDGING BUILDS IN ON


New Orleans Local Weather thread - dkmac - 01-08-2009 06:47 AM

000
fxus64 klix 081048
afdlix

area forecast discussion
national weather service new orleans la
448 am cst thu jan 8 2009

.short term...
Mid/upper trough over eastern north america will shift east today
through friday with a return to zonal flow and much higher heights
aloft/thicknesses expected along the gulf coast. Temperatures this
morning will be starting out quite a bit higher than earlier
forecast...and southwest winds early on will become west to
northwest during the day as a weak west-east trough of low
pressure moves into the forecast area this afternoon. These
conditions combined with plentiful sunshine should cause
temperatures to warm about 8 or 9 degrees warmer than
yesterday...and have gone a few degrees above the mav guidance at
most locations for highs today...and a degree or two above
guidance tonight and friday. Humidity will be increasing as south
winds increase on friday which will also bring a slight increase
in cloud cover friday afternoon.

A positively tilted trough...a result of some phasing of
shortwaves moving out of the northern plains and souther
rockies...will push a cold front into northern and western
sections of mississippi and louisiana late friday night. Have
maintained 20 to 30 percent rain chances after midnight friday
night.

.long term...
The mid/upper shortwave trough will move through the forecast
area saturday and saturday night with the cold front pushing
through most of the forecast area saturday morning and the
east/southeastern portions early saturday afternoon. The gfs looks
a bit fast...so have blended with the slower nam/ecmwf solutions.
Qpf amounts look to be in the .20 to .40 inch range...and since
confidence in timing is pretty good...have raised the pop to the
50 to 60 percent range for saturday. Surface high pressure and dry
and cool air will move into the area saturday night into sunday
as the main shortwave trough moves towards the atlantic coast. Low
temperatures will drop into the 30s early sunday morning...but
should remain above freezing.

A series of shortwave troughs are forecast to move south out of
canada into the mississippi valley monday into early tuesday with a
reinforcing shot of arctic air expected to invade much of the
central and eastern conus. There will be little moisture in our
area...so no precipitation is expected monday and tuesday...however
temperatures are expected to remain below normal with near
freezing lows possible over the colder locations monday through
wednesday mornings. The next chance of rain will be around
thursday as a modest increase in gulf moisture and frontal lift
ahead of additional shortwaves come into play. 22

&&

.aviation...
Surface high pressure is currently centered over the gulf of mexico.
Pressure gradient has remained high enough to keep sw winds elevated
overnight. Winds will gradually become more west and then nw through
the day. Vrb to calm winds expected overnight. Few to sct high
clouds will continue across the area. Vfr conditions will prevail
through the period.

Meffer
&&

.marine...
Sw winds of 15 to 20 kts in the inner and outer coastals east of the
miss are expected to continue into the afternoon...so added small
craft exercise caution headline thru 21z. Sfc ridge will become
center over the are this aftn/eve and should result in decrease in
winds later today. Onshore flow to return thurs as high pressure
shifts eastward. Southeast winds and seas begin increasing as press
gradient tightens in response to approaching cold front. Will need
to watch for sw winds ahead of the front for scy conditions. Slight
discrepancy in timing of this boundary...but should move through
the coastal waters saturday afternoon. Small craft conditions are
possible behind the front as brisk nw winds will accompany the
boundary but should be a relatively short event. Light winds and low
seas sun eve through mon.