162 FXUS64 KLIX 141403 AFDLIX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW ORLEANS LA 903 AM CDT WED MAY 14 2014 .SOUNDING DISCUSSION... NO PROBLEMS WITH FLIGHT THIS MORNING. CONSIDERABLE RECOVERY OF MOISTURE SINCE 00Z WITH PRECIPITABLE WATER INCREASED TO 1.61 INCHES AND LIFTED INDEX UP FROM A STABLE +3 TO A VERY UNSTABLE -9.6. SHALLOW 2C SURFACE BASED INVERSION TO 1000MB...THEN MOIST ADIABATIC TO ANOTHER 2C INVERSION AT 476MB...THEN PSEUDO TO FIRST TROPOPAUSE AT 182MB WITH A TEMPATURE OF -62.1C. A SECOND TROP WAS DETECTED AT 102MB/-72.5C. MOISTURE PROFILE WAS NEAR SATURATION SURFACE TO 690 MB...THEN A RELATIVELY DRY LAYER TO 470MB...THEN SATURATED TO TROPOPAUSE. WIND PROFILE SHOWS DEEP SE FLOW SURFACE TO 800MB GENERALLY LESS THAN 20KT...S-SW 20-85KT ABOVE. PEAK WIND 246/85KT AT 44.2KFT. BALLOON BURST AT 7.06 MB/20.8 MILES UP NEAR PROGRESS ROAD 1 MILE NE OF THE POPLARVILLE/PEARL RIVER COUNTY AIRPORT. USING CHAP ON THIS MORNING'S SOUNDING LIFTING 347K FROM 950 MB YIELDS AT 80 PERCENT CHANCE OF THUNDERSTORMS TODAY. GUST POTENTIAL 32 KT...PEA HAIL POSSIBLE WITH A 71 VIL. EFFICIENT PRECIPITATION 3.39 INCHES INDICATED WITH POTENTIAL FOR 5.77 INCHES FOR TEMPERATURES BELOW 75F. HEAVY RAIN UNDERWAY IN NEW ORLEANS WHERE TEMPERATURE IS 74F...SO FLOODING RAIN POTENTIAL IS IN PLAY FOR TRAIN ECHO DYNAMICS. 24/RR && .PREV DISCUSSION... /ISSUED 358 AM CDT WED MAY 14 2014/ SYNOPSIS... SURFACE COLD FRONT NEARING NORTHWESTERN ZONES...BUT COOLER AIR STILL LAGGING A BIT BEHIND. ISOLATED SHOWERS BEGINNING TO POP UP OVER COASTAL AREAS OF SE LA AND ALSO OVER GULF WATERS EAST OF THE MS RIVER. TEMPS GENERALLY SITTING IN THE LOWER 70S WITH DEWPOINTS IN THE UPPER 60S AND LOWER 70S. DISCUSSION... COLD FRONT WILL SLOWLY MOVE THROUGH THE LOCAL AREA TODAY AS DEEP UPPER TROUGH SLIDES TOWARD THE MISSISSIPPI VALLEY. PLENTY OF MOISTURE WITH ADDED LIFT ALONG AND AHEAD OF THE FRONT SHOULD LEAD RESULT IN SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS THE REGION. BEST INSTABILITY AND FORCING LOOK TO BE NORTH AND EAST OF LOCAL AREA...SO RISK OF SEVERE WEATHER IS LOW...BUT A FEW ISOLATED STORMS COULD BECOME SEVERE THIS AFTERNOON WITH THE MAIN THUNDERSTORM THREATS BEING STRONG/DAMAGING WIND GUSTS AND FREQUENT LIGHTNING. RISK WILL BE HIGHEST ACROSS FAR NORTHEASTERN ZONES WHERE SPC CONTINUES TO INDICATE A SLIGHT RISK OF SEVERE WEATHER MAINLY FOR PIKE AND WALTHALL COUNTIES. STILL LOOKS LIKE A BROKEN SQUALL LINE WILL DEVELOP ALONG THE FRONT AT SOME POINT... THOUGH WHETHER THAT HAPPENS OVER THE LOCAL AREA OR EAST OF THE LOCAL AREA IS A BIT UNCERTAIN. BOTH NCEP WRF AND LATEST HRRR RUNS INDICATE SOME POTENTIAL THAT THE LINE WILL BEGIN TO SOLIDIFY OVER EASTERN ZONES...WITH THE NCEP WRF A BIT MORE AGGRESSIVE THAN THE HRRR. SHOULD ALSO MENTION THAT THERE IS AT LEAST SOME POTENTIAL FOR LOCALLY HEAVY RAINFALL ACROSS EASTERN ZONES WHERE PW VALUES ARE FORECAST TO APPROACH 2 INCHES BY THIS AFTERNOON. THESE VALUES ARE SIMILAR TO WHAT WAS SEEN LAST WEEK AND RAINFALL RATES COULD EASILY TOP 2 INCHES PER HOUR IN SOME OF THE HEAVIER STORMS. THAT BEING SAID...WE COULD START TO SEE SOME PONDING ISSUES IN THE USUAL LOW LYING AND POOR DRAINAGE AREAS. RAIN CHANCES GRADUALLY TAPER OFF FROM WEST TO EAST TONIGHT AS THE UPPER TROUGH AXIS FINALLY SLIDES THROUGH THE LOCAL AREA AND STRONG COLD AIR ADVECTION TAKES HOLD OF THE AREA. LOWS TONIGHT FORECAST TO DROP INTO THE UPPER 40S NORTHWEST TO MID 50S SOUTHEAST...WHICH IS ROUGHLY 25 DEGREES LOWER THAN TEMPERATURES WILL BE THIS MORNING. COOL AND DRY HIGH PRESSURE CONTINUES TO BUILD INTO THE AREA DURING THE DAY TOMORROW AND WILL REMAIN IN PLACE FOR A DAY OR TWO...WITH TEMPERATURES REMAINING BELOW NORMAL THROUGH AT LEAST FRIDAY. THE STRONG COLD AIR ADVECTION WILL RESULT IN BREEZY CONDITIONS TONIGHT AND TOMORROW...ESPECIALLY ACROSS AREAS SOUTH OF THE TIDAL LAKES. DOESN/T LOOK LIKE WE/LL MEET WIND ADVISORY CRITERIA AT THIS TIME...BUT IT COULD GET CLOSE RIGHT ALONG THE SOUTH SHORE OF LAKE PONTCHARTRAIN. SHOULD ALSO MENTION THAT STRONG NORTHERLY WINDS OVER LAKE PONTCHARTRAIN COULD PUSH SOME WATER UP ONTO LAKESHORE DRIVE OUTSIDE OF LEVEE PROTECTION. FOR THAT REASON WILL BE ISSUING A COASTAL FLOOD ADVISORY FOR ORLEANS PARISH THAT WILL BE LIKELY BE IN EFFECT FROM 6PM THIS EVENING THROUGH NOON TOMORROW. GOOD NEWS IS THAT THE STRONGEST WINDS WILL COINCIDE WITH LOW TIDE...SO IMPACTS SHOULD BE MINIMAL. SLOW MODERATION OF THE AIR MASS BEGINS ON SATURDAY AS THE SURFACE HIGH SHIFTS EASTWARD AND AN ONSHORE COMPONENT TO THE WIND RETURNS. DESPITE INCREASE IN MOISTURE AND WARMING AFTERNOON TEMPERATURES... AMPLIFIED UPPER LEVEL RIDGING WILL TAKE HOLD OF THE AREA BY MONDAY AND SUBSIDENCE ALOFT SHOULD KEEP A LID ON CONVECTIVE POTENTIAL. SHOULD BE BACK TO WARM AND MUGGY BY MIDWEEK. AVIATION... EXPECT VFR TO MVFR CONDITIONS TO PREVAIL THROUGH THE FORECAST PERIOD. SHOWERS AND THUNDERSTORMS REMAIN VERY ISOLATED OVERNIGHT AND MAINLY ACROSS THE THE WESTERN PORTIONS OF THE FORECAST AREA POSSIBLY AFFECTING KBTR...KMCB AND KMSY. AS A RESULT...WILL MAINTAIN VICINITY SHOWERS THROUGH AT LEAST 15Z. THERE IS A CHANCE FOR SOME LIGHT PATCHY FOG TO DEVELOP NEAR DAYBREAK AT MCB AND HUM. A COLD FRONT WILL MOVE THROUGH THE AREA TODAY AND COVERAGE WILL INCREASE AT 15Z THROUGH 00Z THURSDAY. LOOKS FOR TEMP/PREVAILING TSRA GROUPS DURING THIS TIME AS THE CONVECTION TRACK FROM WEST TO EAST TODAY AND TAPERING AFTER 00Z THURSDAY. MARINE... SOUTHEAST FLOW HAS EASED IN ADVANCE OF A COLD FRONT. THE COLD FRONT WILL LIKELY TRACK ACROSS THE COASTAL WATERS FROM WEST TO EAST THIS AFTERNOON AND EVENING. STRONG OFFSHORE FLOW WILL DEVELOP IN THE WAKE OF THE AFOREMENTIONED COLD FRONT LATE THIS AFTERNOON AND CONTINUE THROUGH THURSDAY. AFTER THE FRONTAL PASSAGE...STRONG COLD AIR ADVECTION WILL CAUSE THICKNESS LAYER 1000-700MB TO DECREASE AROUND 50M OVER UPPER 70S WATER TEMPS. AS A RESULT...BOUNDARY LAYER WINDS OF 20 TO 25 KNOTS WILL MIXED DOWN TO THE WARM SEA SURFACE LATE THIS AFTERNOON THROUGH THURSDAY EVENING. THEREFORE...A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR ALL COASTAL WATERS 6PM TODAY THROUGH 6PM THURSDAY. THE WINDS WILL GRADUALLY DIMINISH ON FRIDAY. DECISION SUPPORT... DSS CODE...BLUE. DEPLOYED...NONE. ACTIVATION...NONE. ACTIVITIES...SLURRY SUPPORT MONITORING RIVER FLOODING 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 75 47 71 45 / 70 20 10 0 BTR 75 50 74 49 / 60 20 10 0 ASD 80 52 73 49 / 60 30 10 0 MSY 80 56 73 56 / 60 20 10 0 GPT 80 54 74 51 / 70 30 10 0 PQL 82 55 74 46 / 70 40 10 0 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...COASTAL FLOOD ADVISORY FROM 6 PM WEDNESDAY TO NOON THURSDAY FOR THE FOLLOWING ZONES: AND ORLEANS. GM...SMALL CRAFT ADVISORY FROM 6 PM WEDNESDAY TO 6 PM THURSDAY FOR THE FOLLOWING ZONES: BRETON SOUND...CHANDELEUR SOUND...COASTAL WATERS FROM BOOTHVILLE LA TO THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER OUT 20 NM...COASTAL WATERS FROM PASCAGOULA MS TO STAKE ISLAND LA FROM 20 TO 60 NM...COASTAL WATERS FROM PASCAGOULA MS TO STAKE ISLAND LA OUT 20 NM...COASTAL WATERS FROM PORT FOURCHON TO LOWER ATCHAFALAYA RIVER FROM 20 TO 60 NM...COASTAL WATERS FROM PORT FOURCHON TO LOWER ATCHAFALAYA RIVER OUT 20 NM...COASTAL WATERS FROM STAKE ISLAND LA TO THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER FROM 20 TO 60 NM...COASTAL WATERS FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER TO PORT FOURCHON FROM 20 TO 60 NM...COASTAL WATERS FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER TO PORT FOURCHON OUT 20 NM...LAKE BORGNE...LAKE PONTCHARTRAIN AND LAKE MAUREPAS...AND MISSISSIPPI SOUND. MS...NONE. GM...SMALL CRAFT ADVISORY FROM 6 PM WEDNESDAY TO 6 PM THURSDAY FOR THE FOLLOWING ZONES: BRETON SOUND...CHANDELEUR SOUND...COASTAL WATERS FROM BOOTHVILLE LA TO THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER OUT 20 NM...COASTAL WATERS FROM PASCAGOULA MS TO STAKE ISLAND LA FROM 20 TO 60 NM...COASTAL WATERS FROM PASCAGOULA MS TO STAKE ISLAND LA OUT 20 NM...COASTAL WATERS FROM PORT FOURCHON TO LOWER ATCHAFALAYA RIVER FROM 20 TO 60 NM...COASTAL WATERS FROM PORT FOURCHON TO LOWER ATCHAFALAYA RIVER OUT 20 NM...COASTAL WATERS FROM STAKE ISLAND LA TO THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER FROM 20 TO 60 NM...COASTAL WATERS FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER TO PORT FOURCHON FROM 20 TO 60 NM...COASTAL WATERS FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER TO PORT FOURCHON OUT 20 NM...LAKE BORGNE...LAKE PONTCHARTRAIN AND LAKE MAUREPAS...AND MISSISSIPPI SOUND. && $$