FXUS64 KLCH 201203 AFDLCH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LAKE CHARLES LA 700 AM CDT SUN APR 20 2014 .DISCUSSION... FOR THE 20/12Z TAF ISSUANCE. && .AVIATION... AREAS OF FOG DEVELOPED ACROSS SOUTHEAST TEXAS AND SOUTHWEST LOUISIANA THIS MORNING WHERE RADIATIONAL COOLING AND LOW LEVEL MOISTURE WERE HIGH. GOES-E MVFR/IFR/LIFR PROBABILITY CHARTS SHOWED FOG CONCENTRATION MAINLY CONFINED IN THE TERMINAL AIRPORT AREAS OF BPT AND LCH EARLY THIS MORNING. BPT WAS THE CLEAR PROBLEM SPOT AS LIFR VISIBILITY/CLOUD CONDITIONS SEEN THERE BEFORE SUNRISE. EXPECT CONDITIONS TO IMPROVE SLOWLY THIS MORNING ACROSS SOUTHEAST TEXAS WHERE FOG WAS A BIT THICK. ELSEWHERE...ALL TAF SITES IN SOUTHWEST AND CENTRAL LOUISIANA SHOULD BE VFR BY 15Z. FOG EXPECTED TO RETURN AGAIN TONIGHT AS FORECAST CONDITIONS REMAIN SIMILAR. 06 && .DISCUSSION... LATEST WATER VAPOR SATELLITE IMAGERY/UPPER AIR ANALYSIS SHOWED A VIGOROUS UPPER LOW OFF THE COAST OF THE CAROLINAS...WITH AN UPSTREAM TROF EMERGING EAST O THE FOUR CORNERS INTO WEST TX. BETWEEN THESE TWO FEATURES...MID/UPPER RIDGING WAS NOTED ACROSS THE WRN GULF NORTHWARD INTO THE MID MS RIVER VALLEY. AT THE SFC...A RIDGE OF HIGH PRESSURE STRETCHED FROM ERN CANADA INTO THE NW GULF. DEEP LAYER RIDGING IS FCST TO CONTINUE TO PREVAIL TODAY...LEADING TO A GENERALLY MOSTLY SUNNY SKY AND LIGHT WINDS AS AFTERNOON TEMPERATURES CLIMB TO THE UPPER 70S TO LOWER 80S. HIGH CLOUDS WILL CONTINUE TO STREAM OVERHEAD AS MOISTURE ALOFT IS CARRIED IN BY THE SUBTROPICAL JET...BUT OTHERWISE JUST EXPECT SOME FAIR WEATHER CU BY LATE MORNING AND INTO THE AFTERNOON. OBS ACROSS SE TX/SW LA INDICATE AREAS OF FOG...SOME DENSE...HAVE DEVELOPED OVER THE GOLDEN TRIANGLE AND INTO SW LA VIA A COMBINATION OF ADVECTION/RADIATION PROCESSES. HAD INSERTED PATCHY FOG INTO THE GRIDS OVER SE TX FOR THE FIRST FEW HOURS OF THE MORNING...BUT IN THE PROCESS OF WRITING THIS AFD...THE FOG HAS WORSENED AND EXPANDED EASTWARD. AN ADVISORY WILL BE ISSUED SHORTLY. THE UPPER TROUGH TO THE WEST IS PROGGED TO LIFT OUT TO THE NORTHEAST TODAY...CROSSING THE MID MS RIVER VALLEY ON MONDAY. THE MEAN TROF AXIS...HOWEVER...WILL LAG A BIT BEHIND...NOT TRAVERSING THE REGION UNTIL LATE MONDAY INTO TUESDAY. CONTINUED WITH LOW END POPS MONDAY NIGHT INTO TUESDAY AS THE TROF NUDGES A WEAK FRONT INTO THE AREA. THE FRONT IS EXPECTED TO HANG UP NEAR THE COAST TUESDAY NIGHT...WITH LITTLE CHANGE EXPECTED TO TEMPERATURES OTHER THAN A BRIEF HALT TO THE MODERATING TREND. CONTINUED TO KEEP WEDNESDAY DRY...BUT THIS COULD CHANGE AS GLOBAL MODELS ARE STARTING TO INDICATE SOME RAINFALL POTENTIAL AS THE FRONT WASHES OUT AND LIFTS BACK NORTHWARD. GENERALLY ZONAL FLOW ALOFT IS PROGGED TO PREVAIL FOR THE REST OF THE WEEK AND INTO THE UPCOMING WEEKEND. NO BIG CHANGES MADE TO THIS PART OF THE FORECAST. 13 && .MARINE... LIGHT WINDS AND LOW SEAS ARE EXPECTED TO PERSIST AS HIGH PRESSURE BUILDS ACROSS THE AREA THROUGH THE REMAINDER OF EASTER WEEKEND INTO EARLY NEXT WEEK. A WEAK FRONT IS EXPECTED TO BRING A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS ON TUESDAY...WITH THE FRONT EXPECTED TO WASH OUT ALONG THE COAST. AN INCREASING PRESSURE GRADIENT WILL BRING AN INCREASED ONSHORE FLOW BY WEDNESDAY AND THURSDAY. 13 && .PRELIMINARY POINT TEMPS/POPS... KLCH 81 60 79 61 / 10 10 10 20 KBPT 81 60 79 62 / 10 10 10 20 KAEX 81 58 80 60 / 10 10 20 30 KLFT 81 59 80 61 / 10 10 10 20 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR CALCASIEU- WEST CAMERON. TX...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR HARDIN- JEFFERSON-ORANGE-SOUTHERN JASPER-SOUTHERN NEWTON. GM...NONE. && $$ PUBLIC/MARINE...13