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

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904
FXUS64 KLIX 210143
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
843 PM CDT MON APR 20 2015

...SOUNDING DISCUSSION...

PRECIPITABLE WATER VALUES ARE BACK DOWN UNDER AN INCH AND BELOW
NORMAL THIS EVENING. THE LOWER PW HAS PROVIDED FOR A REALLY
COMFORTABLE DAY ACROSS THE CENTRAL GULF COAST STATES. A TEMPERATURE
INVERSION WAS LOCATED BETWEEN 3000 TO 4200 FEET. WINDS WERE FROM
THE NORTHEAST IN THE LOW LEVELS...THEN PRIMARILY FROM THE EAST IN
THE MIDDLE AND UPPER LEVELS. A PEAK WIND SPEED OF 136 KNOTS WAS AT
40300 FEET.

00Z BALLOON INFO: THE BALLOON ASCENDED FOR 107 MINUTES TO A
HEIGHT OF 21.4 MILES ABOVE THE GROUND BURSTING JUST WEST OF GULF
SHORES MS 108 MILES DOWNRANGE FROM THE OFFICE.

ANSORGE

&&

.PREV DISCUSSION... /ISSUED 406 PM CDT MON APR 20 2015/

SYNOPSIS...
LATEST SURFACE ANALYSIS SHOWED A COLD FRONT FROM OHIO TO FLORIDA
PANHANDLE TO NORTHWEST GULF. SURFACE DEWPOINT READINGS WERE IN THE
40S ACROSS MOST OF WEST LOUISIANA AND NORTHERN TWO-THIRDS OF
MISSISSIPPI. RIDGE OF HIGH PRESSURE WAS LOCATED FROM SOUTHWEST
KANSAS TO NORTH CENTRAL TEXAS. UPPER AIR ANALYSIS SHOWED A LARGE
CYCLONIC OVER MINNESOTA WITH WEST TO NORTHWEST FLOW OVER PLAINS
AND MISSISSIPPI VALLEY. ISOTACH ANALYSIS SHOWED THE SOUTHERN
STREAM FROM BAJA CALIFORNIA TO NORTH CENTRAL GULF.

SHORT TERM...
DRY AIR AND HIGH PRESSURE WILL SETTLE IN TONIGHT THROUGH TUESDAY
NIGHT. THESE FEATURES ALONG TO NEAR CALM WINDS WILL ALLOW GOOD
RADIATIONAL COOLING TONIGHT AND TUESDAY EVENING. WITH DEWPOINTS
BOTTOMING OUT NEAR 50F ACROSS NORTHWEST FORECAST AREA...CANT RULE
A 49F AT MCB AND NORTH OF BTR TUESDAY MORNING. THE MAIN TROUGH
WILL SHIFT EAST LEAVING A WESTERLY FLOW OVER THE FORECAST AREA AND
LOWER MISSISSIPPI VALLEY EARLY WEDNESDAY. SURF HIGH WILL SLIDE
GEORGIA AND RETURN FLOW WILL BRING IN 60S DEWPOINT BY 18Z
WEDNESDAY. RIDGE OVER THE ROCKIES WILL SLIDE EAST AND CREATE A
WEST NORTHWEST FLOW OVER SOUTHERN PLAINS AND LOWER MISSISSIPPI
VALLEY WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT. IN EMBEDDED
DISTURBANCE WILL DIVE DOWN ON THE FRONT SIDE OF THE RIDGE AND
TRIGGER CONVECTION OVER SOUTHERN PLAINS WEDNESDAY AFTERNOON. THIS
CONVECTION MAY HOLD TOGETHER WITH THE ACTIVE JET STREAM AND
INSTABILITY IN PLAY. ISOLATED STRONG STORMS MAY CLIP THE NORTH AND
EAST AREAS OF FORECAST AREAS...POSSIBLY PARTS OF EAST CENTRAL
LOUISIANA NORTH OF LAKE PONTCHARTRAIN...EXTREME SOUTH CENTRAL
MISSISSIPPI AND COASTAL MISSISSIPPI LATE WEDNESDAY AFTERNOON AND
WEDNESDAY EVENING. ALBEIT IS SLIGHT...HAIL AND DAMAGING WINDS ARE
THE MAIN THREATS. COOLER 5H TEMPS AROUND -16C WILL REMAIN NORTH
AND HAIL THREAT WILL DIMINISH FARTHER SOUTH INTO OUR FORECAST
AREA.

WITH NO REAL PUSH AT THE SURFACE...LOW LEVEL INSTABILITY
WILL REMAIN IN PLAY ON THURSDAY AND A CHANCE OF CONVECTION WILL
REMAIN ACROSS THE AREA. UPPER LEVEL RIDGE WILL CONTINUE TO SLIDE
EAST AND ALLOW DAYTIME SURF TEMPS TO WARM THURSDAY THROUGH
SATURDAY. RIDGE WILL SLIDE EAST AS A SHORT WAVE MOVE EAST ACROSS
THE CENTRAL PLAINS FRIDAY THROUGH SATURDAY. DRY AIR ENTRAINMENT
SOUTH OF THE WAVE WILL TIGHTEN THE MOISTURE AXIS ACROSS THE AREA
SATURDAY AND SATURDAY NIGHT...THUS MAINTAINING A CHANCE OF
CONVECTION. AS THE WAVE PUSHES EAST...DRY AIR WILL PRESS THE
MOISTURE AXIS SOUTH SUNDAY AND PROVIDE A SLIGHT BREAK ON SUNDAY.
ANOTHER WAVE WILL DIVE SOUTH OVER THE PLAINS BRINGING A SHOT OF
COOL AIR NEXT WEEK. 18

AVIATION...
VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE PERIOD WITH GENERALLY
ONLY HIGH CLOUDS. WINDS EXPECTED TO SHIFT FROM NORTHWEST THIS
AFTERNOON TO EASTERLY BY TUESDAY MORNING WITH SPEEDS GENERALLY 10
KNOTS OR LESS. MAIN EXCEPTIONS WILL BE THOSE TERMINALS ON THE
IMMEDIATE SOUTH SHORE OF LAKE PONTCHARTRAIN. 95/DM


MARINE...
NORTHWEST WINDS OF 10 TO 15 KNOTS WILL INCREASE TO EXERCISE
CAUTION RANGE THIS EVENING AND OVERNIGHT WITH WINDS UP TO 15 TO 20
KNOTS AND WAVE HEIGHTS GETTING UP TO AROUND 3-5 FEET OVER THE
OPEN WATERS. WINDS WILL QUICKLY RETURN TO AN ONSHORE EARLY
WEDNESDAY MORNING AS HIGH PRESSURE PASSES TO THE EAST OF THE
AREA. WINDS WILL REMAIN AROUND 10 KNOTS DURING THE MIDDLE OF THE
WEEK...BUT COULD RAMP UP TO ABOUT 15 KNOTS AT THE END OF THE WEEK
AS ANOTHER FRONT APPROACHES. WAVE HEIGHTS AT THAT TIME COULD GET
UP TO 4-5 FEET OVER THE OPEN WATERS. 18

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

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 TONIGHT RISK SVR
         AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
         SIGNIFICANCE

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  49  77  54  83 /   0   0   0  40
BTR  53  79  58  85 /   0   0  10  30
ASD  52  77  58  82 /   0   0  10  30
MSY  60  76  65  83 /   0   0  10  30
GPT  54  76  61  81 /   0   0  10  30
PQL  53  77  55  82 /   0   0  10  20

&&

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

$$



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