Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

133
FXUS64 KLIX 202159
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
359 PM CST TUE JAN 20 2015

.SHORT TERM...

A VERY PROGRESSIVE ZONAL FLOW PATTERN WILL CONTINUE TO DOMINATE
THE GULF SOUTH THROUGH FRIDAY. A WEAK SHORTWAVE CURRENTLY MOVING
THROUGH THE REGION WILL QUICKLY PUSH TO THE EAST TONIGHT. IN THE
WAKE OF THIS FEATURE...EVEN DRIER AIR WILL MOVE IN BEHIND A WEAK
FRONTAL BOUNDARY. BEFORE THIS FRONT MOVES THROUGH...THE CLEAR
SKIES AND LIGHT WINDS ALONG WITH SLIGHTLY HIGHER DEWPOINTS COULD
ALLOW FOR SOME PATCHY FOG FORMATION DURING THE OVERNIGHT HOURS.
ONCE THE FRONT MOVES THROUGH LATE TONIGHT AND EARLY TOMORROW...WINDS
WILL SHIFT TO THE NORTH AND INCREASE IN SPEED TO AROUND 5 TO 10
KNOTS AS THE FRONT PUSHES OFFSHORE. THIS INCREASE IN
MIXING...COMBINED WITH THE EXPECTED DRY AIR ADVECTION WILL QUICKLY
CLEAR ANY FOG AND CLOUD COVER OVER THE AREA. OVERALL...MOSTLY CLEAR
SKIES AND LOW HUMIDITIES ARE EXPECTED THROUGH THE DAY. GIVEN THE
CLEAR AND DRY CONDITIONS...THERE WILL BE A FAIRLY LARGE DIURNAL
RANGE ON THE ORDER OF 25 DEGREES. OVERNIGHT LOWS IN THE LOWER TO
MIDDLE 40S WILL QUICKLY CLIMB INTO THE UPPER 60S AND POSSIBLY
LOWER 70S BY THE AFTERNOON HOURS.

HEADING INTO WEDNESDAY NIGHT...CONDITIONS WILL BEGIN TO TRANSITION
AS A MUCH STRONGER PACIFIC TROUGH PULLS OUT OF THE FOUR CORNERS.
AS THIS UPPER LEVEL TROUGH APPROACHES FROM THE EAST...A STRONG 120
KNOT JET STREAK WILL DEVELOP OVER THE REGION. AT THE SAME
TIME...PACIFIC BASED MOISTURE WILL BEGIN TO FEED INTO THE MID AND
UPPER LEVELS OF THE ATMOSPHERE. MOISTURE WILL CONTINUE TO FEED
INTO THE AREA THROUGH THE NIGHT...AND EXPECT TO SEE PRECIPITABLE
WATER VALUES CLOSE TO SEASONAL NORMS BY LATE WEDNESDAY NIGHT.
THERE WILL STILL BE A DRY LAYER IN PLACE BELOW 600 MB...BUT WITH
INCREASING OMEGA ASSOCIATED WITH THE JET STREAK AND INCREASING
DIFLUENCE ALOFT...SOME LIGHT SHOWER ACTIVITY COULD DEVELOP BY LATE
WEDNESDAY NIGHT.

THE ATMOSPHERE WILL BECOME FURTHER SATURATED THROUGHOUT THE DAY ON
THURSDAY...AND UPPER LEVEL LIFT WILL INCREASE DUE TO THE
COMBINATION OF JET DYNAMICS...DIFLUENT FLOW...AND INCREASING
POSITIVE VORTICITY ADVECTION. AS A RESULT...OVERCAST CONDITIONS
AND INCREASING COVERAGE OF SHOWERS IS EXPECTED. ADDITIONALLY...A
SURFACE LOW WILL BEGIN TO FORM OVER THE WESTERN GULF OF MEXICO IN
A REGION OF ENHANCED BAROCLINICITY AND FAVORABLE LIFT. AS THIS LOW
DEEPENS...THE PRESSURE GRADIENT OVER THE AREA AND RESULTANT WIND
FIELD WILL INCREASE. EXPECT TO SEE A SUSTAINED NORTHEAST WIND OF
15 MPH OR GREATER THROUGH THE DAY. THIS NORTHEAST FLOW WILL ALSO
DRAG DOWN A SHALLOW LAYER OF COOLER AND MORE STABLE AIR IN THE
LOWEST LEVELS OF THE ATMOSPHERE. AT THE SAME TIME... STRONG WARM
FRONTAL PROCESSES AND RESULTANT ISENTROPIC FORCING OVER THE COOLER
AND MORE STABLE SURFACE BASED AIRMASS WILL DEVELOP IN THE
MIDLEVELS. EXPECT TO SEE A SHIELD OF LIGHT TO MODERATE RAINFALL
OVERSPREAD MOST OF THE FORECAST THURSDAY EVENING AND PERSIST INTO
EARLY FRIDAY AS THE SURFACE LOW TRACKS THROUGH THE REGION. HAVE
WENT WITH CATEGORICAL POPS FOR THIS TIME FRAME DUE TO THE HIGH
CONFIDENCE THAT THIS RAINFALL WILL OCCUR. TEMPERATURES WILL BE
SIGNIFICANTLY COOLER ON THURSDAY DUE TO THE COMBINATION OF COLD
AIR ADVECTING IN FROM THE NORTHEAST AND INCREASED CLOUD COVER.
HIGHS WILL STRUGGLE TO REACH INTO THE MIDDLE 50S.
FORTUNATELY...TEMPERATURES ARE ONLY EXPECTED TO COOL ABOUT 10
DEGREES FROM THE DAYTIME HIGHS THURSDAY NIGHT...WITH READINGS
GENERALLY IN THE 40S.

HEADING INTO FRIDAY...THE SURFACE LOW WILL PULL TO THE EAST OF THE
AREA...AND ISENTROPIC FORCING WILL WANE. AS A RESULT...EXPECT TO
SEE THE BROAD SHIELD OF RAINFALL PUSH TO THE EAST...BUT SHOWERS
WILL LINGER THROUGH THE DAY AS THE PARENT UPPER LEVEL TROUGH AXIS
AND A COLD FRONT SWEEP THROUGH THE FORECAST AREA. AS THE COLD POOL
ASSOCIATED WITH THE UPPER LEVEL LOW TRACKS THROUGH THE AREA FRIDAY
INTO FRIDAY NIGHT...TEMPERATURES WILL BE A GOOD 15 DEGREES BELOW
NORMAL. HIGHS WILL STRUGGLE TO RISE INTO THE UPPER 40S FRIDAY
AFTERNOON...AND OVERNIGHT LOWS WILL DROP INTO THE MIDDLE 30S
FRIDAY NIGHT. FORTUNATELY...IT LOOKS LIKE THE COLDEST AIR
ASSOCIATED WITH THE UPPER LEVEL LOW WILL MOVE IN AFTER THE
MOISTURE HAS SHIFTED TO THE EAST OF THE REGION. THUS...ONLY LIQUID
PRECIPITATION IS EXPECTED OVER THE FORECAST AREA FRIDAY EVENING

.LONG TERM...

AS THIS PACIFIC BASED TROUGH SLIDES TO THE EAST ON SATURDAY...THE
OVERALL UPPER LEVEL PATTERN WILL SHIFT FROM A ZONAL FLOW REGIME TO
A MORE AMPLIFIED PATTERN. EXPECT TO SEE A PERSISTENT TROUGH FORM
OVER THE EASTERN HALF OF THE COUNTRY AND REMAIN IN PLACE THROUGH
EARLY NEXT WEEK. STRONG DRY AIR ADVECTION AND INCREASING
SUBSIDENCE ALOFT WILL BRING CLEAR SKIES TO THE FORECAST AREA FOR
THE WEEKEND. TEMPERATURES WILL REMAIN BELOW NORMAL ON SATURDAY AS
THE COLD POOL ALOFT LINGERS OVER THE REGION...AND WITH CLEAR AND
DRY CONDITIONS IN PLACE...OVERNIGHT LOWS WILL COOL BACK INTO THE
30S FOR SATURDAY NIGHT. SOME MODERATION IN TEMPERATURES IS
EXPECTED ON SUNDAY...BUT HIGHS WILL ONLY RISE BACK TO MORE NORMAL
LEVELS FOR LATE JANUARY IN THE LOWER 60S.

A VIGOROUS CLIPPER SYSTEM WILL DIVE DOWN FROM THE CANADIAN PLAINS
AND INTO THE GREAT LAKES STATES SUNDAY NIGHT AND SWING THROUGH THE
MID-ATLANTIC ON MONDAY. A STRONG REINFORCING COLD FRONT WILL SWEEP
THROUGH THE FORECAST AREA SUNDAY NIGHT...BRINGING COOLER
CONDITIONS TO THE REGION FOR MONDAY AND TUESDAY. HIGHS WILL ONLY
RISE INTO THE MIDDLE TO UPPER 50S EACH DAY...AND OVERNIGHT LOWS
WILL COOL INTO THE 30S OVER MOST OF THE REGION. THE REGION WILL
REMAIN MOISTURE STARVED...SO ONLY A FEW PASSING HIGH CLOUDS ARE
EXPECTED AS THE CLIPPER SYSTEM SLIDES THROUGH.

&&

.AVIATION...

VFR CONDITIONS WILL DOMINATE THE PERIOD AT ALL TERMINALS. A PERIOD
OF AROUND 6 HOURS OF PATCHY LIGHT TO OCCASIONALLY MODERATE FOG WILL
BE POSSIBLE AFTER MIDNIGHT THROUGH AROUND SUNRISE. WINDS WILL REMAIN
RELATIVELY LIGHT.

MEFFER

&&

.MARINE...

THE NEXT SIGNIFICANT SYSTEM TO IMPACT THE COASTAL WATERS WILL BE A
STRONG GULF LOW MOVING THROUGH THE REGION ON THURSDAY AND FRIDAY.
INCREASING NORTHEAST FLOW IS EXPECTED TO DEVELOP TOMORROW AND
SHOULD PUSH INTO SMALL CRAFT ADVISORY RANGE AS THE LOW MOVES
THROUGH THE NORTHERN GULF OF MEXICO ON THURSDAY AND FRIDAY. WINDS
WILL FURTHER INCREASE FRIDAY NIGHT AND SATURDAY AS THE LOW PULLS
TO THE EAST AND A VERY DRY AND COLD AIRMASS MOVES INTO THE REGION.
EXPECT TO SEE NORTHWEST FLOW OF 20 TO 25 KNOTS AND SEAS OF 7 TO 9
FEET DURING THIS PERIOD. A BRIEF BREAK IN THE ADVISORY CONDITIONS
WILL DEVELOP SATURDAY NIGHT AND SUNDAY...BUT A REINFORCING FRONT
SUNDAY NIGHT WILL PUSH WINDS BACK INTO ADVISORY RANGE ON MONDAY.

&&

.DECISION SUPPORT...

DSS CODE...GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT.

DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN  = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE   = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
         VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
         WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
         TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED    = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK SVR
         AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
         SIGNIFICANCE.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  44  66  44  53 /   0   0  30  70
BTR  47  68  45  54 /   0   0  40  80
ASD  45  67  45  55 /   0   0  30  60
MSY  48  66  48  57 /   0   0  30  70
GPT  46  67  47  56 /   0   0  20  50
PQL  43  67  46  57 /   0   0  20  50

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&

$$

32





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.