636
FXUS64 KLIX 091329
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
729 AM CST TUE FEB 9 2010
UPDATE
SOUNDING DISCUSSION
THE ATMOSPHERE REMAINS MOIST BELOW 600 MB WITH A PRECIPITABLE
WATER VALUE OF 0.80 INCHES. THE RAIN HAS MOVED OUT OF THE CWA
HOWEVER A STRATUS DECK NEAR 3000 FEET REMAINS OVER THE AREA. AN
INVERSION IS PRESENT NEAR 850 MB ALONG WITH NORTHWEST WINDS NEAR
THE SURFACE AND WEST AND SOUTHWEST WINDS ALOFT...STRONG MID AND
UPPER LEVEL WINDS ARE PRESENT.
PREV DISCUSSION
/ISSUED 646 AM CST TUE FEB 9 2010/
UPDATE...
UPDATED THIS MORNING TO REMOVE MENTION OF RAIN FROM LAND AREAS.
SOME PATCHY VERY LIGHT DRIZZLE IS POSSIBLE IN SOME AREAS...BUT THE
CHANCE OF MEASURABLE RAIN IS 10 PERCENT OR LESS. ALSO UPDATED A
FEW OF THE HOURLY TEMPERATURE GRIDS EARLY THIS MORNING TO ACCOUNT
FOR THE SLIGHTLY SLOWER THAN EXPECTED COLDER AIR.
22/TD
AVIATION...
TRAILING EDGE OF RAIN HAS CLEARED ALL THE TERMINALS. EXPECT IFR TO
MVFR CEILINGS TO PERSIST THIS MORNING. MODELS INDICATE DRYING
SHOULD BE SIGNIFICANT ENOUGH TO BREAK UP CLOUD DECK EARLY
AFTERNOON AT KBTR AND KMSY...AND MID TO LATE AFTERNOON AT KMCB AND
KGPT.
PREV DISCUSSION... /ISSUED 508 AM CST TUE FEB 9 2010/
.FROZEN PRECIPITATION IS LIKELY OVER PORTIONS OF THE AREA LATE
THURSDAY INTO FRIDAY...
SHORT TERM...
COLD FRONT IS PUSHING THROUGH THE FORECAST AREA AND WILL CLEAR
THE EASTERN MISSISSIPPI COAST AND LOWER PLAQUEMINES PARISH BY MID
MORNING. LINGERING SLIGHT CHANCE TO CHANCE OF SHOWERS WILL QUICKLY
END THIS MORNING...THEN PARTLY TO MOSTLY SUNNY SKIES WILL RETURN
DURING THE AFTERNOON. STRONG COLD AIR ADVECTION WILL MAKE FOR A
RATHER COOL DAY WITH HIGHS WELL BELOW THE SEASONAL NORMS AT MOST
LOCATIONS. IT WILL BE RATHER BREEZY TOO...ESPECIALLY NEAR LAKE
PONTCHARTRAIN AND THE COAST. TEMPERATURES LATE THIS AFTERNOON AND
EARLY THIS EVENING WILL FALL THROUGH THE 40S WITH WIND CHILL
VALUES FALLING TO THE 30S. LATE TONIGHT...UNDER CLEAR SKIES A
LIGHT TO MODERATE FREEZE IS EXPECTED NORTH AND WEST OF LAKE
PONTCHARTRAIN INTO SOUTH MISSISSIPPI. LOWS ON THE SOUTH SHORE
SHOULD REMAIN JUST ABOVE FREEZING...HOWEVER...A BRIEF FREEZE IS
POSSIBLE IN SOME COLDER LOCATIONS AWAY FROM THE LAKE AND
COAST...ALONG WITH WIND CHILL READINGS IN THE 20S.
WEDNESDAY WILL START OUT SUNNY...THEN HIGH CLOUDS WILL INCREASE IN
THE AFTERNOON. IT WILL BE ANOTHER RATHER COOL DAY WITH HIGHS IN
THE UPPER 40S TO LOWER 50S WHICH IS 10 TO 15 DEGREES BELOW THE
SEASONAL NORMS. WEDNESDAY NIGHT WILL BE COLD AGAIN...BUT NOT
QUITE AS COLD AS TONIGHT DUE TO THE EXPECTED INCREASE IN CLOUD
COVER.
LONG TERM...
FROZEN PRECIPITATION IS STILL LIKELY WITH THE NEXT STORM SYSTEM
STARTING LATE THURSDAY...BUT ESPECIALLY THURSDAY NIGHT INTO EARLY
FRIDAY MORNING. THE EXPECTED PATTERN IS STILL THE SAME...COLD AIR
WILL BE IN PLACE THURSDAY MORNING...AND A POTENT SHORTWAVE TROUGH
WILL BE MOVING ACROSS THE TEXAS/MEXICAN BORDER AREA ON THURSDAY.
THIS WILL CAUSE SURFACE LOW PRESSURE TO DEVELOP IN THE NORTHWEST
GULF OF MEXICO THURSDAY AND THURSDAY NIGHT WITH THE LOW EXPECTED
TO TRACK EAST ACROSS THE NORTHERN GULF THURSDAY NIGHT THROUGH
FRIDAY EVENING. THE 00Z GFS HAS THE WEAKEST 500 MB SHORTWAVE
TROUGH AND ONE OF THE FARTHER SOUTH TRACKS OF THE SURFACE LOW. THE
00Z NAM APPEARS TO BE THE SLOWEST MODEL...AND THE ECMWF REMAINS
FAIRLY CONSISTENT WITH THE SURFACE LOW TRACK...BUT APPEARS TOO
HIGH WITH THE QPF ON THE NORTHERN FRINGE OF THE PRECIP SHIELD.
DUE TO THE UNCERTAINTY...HAVE USED A BLEND OF THE GFS AND ECMWF
WITH THE MASS FIELDS AND QPF.
NOW THE TRICKY PART...THE FORECAST PRECIPITATION TYPE. MODEL
SOUNDINGS FOR MCCOMB MISSISSIPPI ARE STILL VERY SUPPORTIVE OF
MOSTLY SNOW...POSSIBLY STARTING OUT AS A MIX OF RAIN...SLEET...AND
SNOW THURSDAY AFTERNOON BUT LIKELY CHANGING TO ALL SNOW THURSDAY
EVENING. 850 MB TEMPERATURES FROM MOST MODELS ARE NEAR OR SLIGHTLY
ABOVE ZERO...AND THAT IS UNFAVORABLE FOR HEAVY SNOW...HOWEVER...A
PERIOD OF MODERATE SNOW IS POSSIBLE ACROSS SOUTHWEST MISSISSIPPI
AND POSSIBLY A SMALL PORTION OF THE UPPER FLORIDA PARISHES...NORTH
OF BATON ROUGE WITH SEVERAL INCHES OF SNOW ACCUMULATION POSSIBLE.
TO THE SOUTH...METRO BATON ROUGE...THE NORTHSHORE...AND AREAS OF
SOUTHEAST MISSISSIPPI JUST INLAND FROM THE COAST MAY EXPERIENCE A
RAIN AND SLEET MIX TO START DUE TO WET BULB EFFECT...THEN MODEL
SOUNDING TEMPERATURE PROFILES ARE MARGINAL BETWEEN SUPPORTING
ALL RAIN AND A MIX OF RAIN AND SNOW. HAVE KEPT THE MIXED PRECIP
WORDING FOR NOW. ON THE SOUTHSHORE...MOSTLY RAIN IS
EXPECTED...ALTHOUGH SOME SLEET IS POSSIBLE AT THE ONSET THURSDAY
AFTERNOON. PRECIPITATION SHOULD END IN THE WEST FRIDAY MORNING AND
IN EASTERN SECTIONS EARLY FRIDAY AFTERNOON.
NOTE...THERE ARE STILL UNCERTAINTIES ON THE TRACK AND TIMING OF
THIS POTENTIAL WINTER STORM SYSTEM...SO STAY TUNED TO THE LATEST
FORECASTS ON THIS SYSTEM. REFER TO THE LATEST HAZARDOUS WEATHER
OUTLOOK...WINTER WEATHER HAZARDS SECTION FOR ADDITIONAL
INFORMATION.
AFTER PRECIP ENDS ON FRIDAY...IT WILL REMAIN MOSTLY
CLOUDY...BREEZY AND COLD FOR PARADES IN THE EVENING. SATURDAY
WILL BE COOL BUT DRY FOR THE PARADES...THEN ANOTHER COLD FRONT WILL
BRING A SLIGHT CHANCE OF RAIN OR SHOWERS ON SUNDAY. THIS SYSTEM
DOES NOT LOOK TO HAVE MUCH MOISTURE TO WORK WITH...SO ANY RAINFALL
SHOULD BE LIGHT.
MONDAY AND NEXT TUESDAY...LUNDI GRAS AND MARDI GRAS...SURFACE
HIGH PRESSURE SHOULD CONTROL THE WEATHER AND BRING DRY CONDITIONS
WITH CONTINUED BELOW NORMAL TEMPERATURES.
22/TD
MARINE...
COLD FRONT PROGRESSING THROUGH AREA ON SCHEDULE. SEE NO REAL NEED
TO MESS WITH CURRENT STRUCTURE OF HEADLINES. EXPECT THAT LAKES
WILL TREND FROM ADVISORY TO EXERCISE CAUTION THIS EVENING...THEN
TO NO HEADLINE BY WEDNESDAY MORNING. ADVISORY OVER COASTAL WATERS
WILL LIKELY GO TO EXERCISE CAUTION WEDNESDAY MORNING...THEN TO NO
HEADLINE BY WEDNESDAY EVENING. ABOUT A 24 HOUR RESPITE UNTIL NEXT
LOW APPROACHES AREA THURSDAY NIGHT. GFS SOLUTION A LITTLE FURTHER
SOUTH TONIGHT...WITH WINDS A LITTLE LESS POWERFUL THAN EARLIER
ANTICIPATED FOR FRIDAY...BUT STILL WORTHY OF ADVISORY...FRIDAY AND
FRIDAY NIGHT. EXPECT A REINFORCING SHOT OF COLD AIR SUNDAY NIGHT
TO REINVIGORATE THE WINDS AS WELL. UPSHOT IS THAT ANY PERIODS OF
WINDS NOT REQUIRING HEADLINES OVER THE NEXT SEVERAL DAYS WILL BE
SHORT LIVED.
35
PRELIMINARY POINT TEMPS/POPS
MCB 47 27 49 31 / 10 0 0 10
BTR 49 29 51 33 / 10 0 0 20
ASD 51 29 51 32 / 10 0 0 10
MSY 51 33 49 36 / 10 0 0 20
GPT 56 29 51 31 / 10 0 0 10
PQL 56 28 51 30 / 10 0 0 10
LIX WATCHES/WARNINGS/ADVISORIES
LA...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR GMZ530.
SMALL CRAFT ADVISORY UNTIL 6 AM CST WEDNESDAY FOR GMZ550-555-570-
575.
MS...NONE.
GM... SMALL CRAFT ADVISORY UNTIL 6 AM CST WEDNESDAY FOR GMZ555-570-575.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page