000 FXUS62 KILM 300657 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 257 AM EDT SAT AUG 30 2008 .SYNOPSIS... AREA BEACHES WILL SEE AN INCREASED THREAT OF RIP CURRENTS THIS UPCOMING WEEK AS SWELLS FROM HANNA ARRIVE. OTHERWISE...A WEAK TROUGH OF LOW PRESSURE WILL LINGER OVER THE EASTERN CAROLINAS THROUGH SATURDAY. A COLD FRONT WILL PUSH SOUTHEAST ACROSS THE REGION SUNDAY INTO EARLY MONDAY. HIGH PRESSURE WILL BUILD IN FROM THE NORTH MONDAY THROUGH THE MIDDLE OF NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 3 AM SATURDAY...WILL HAVE TO DEAL WITH SOME FOG THROUGH SUNRISE...POSSIBLY LOCALLY DENSE AT TIMES INLAND AREAS. THE FOG WILL BURN OFF AN HOUR OR SO AFTER SUNRISE...YIELDING PARTLY CLOUDY SKIES. A WEAK UPPER LOW...NOTED ON WATER VAPOR IMAGERY ACROSS SC WILL CONTINUE TO DIRECT A NARROW CHANNEL OF MOISTURE INTO THE CAROLINAS. THE UPPER LOW...ALONG WITH LIFT PROVIDED BY THE SEA BREEZE SHOULD BE ENOUGH TO SPARK SCATTERED SHRA/TSRA DURING THE DAY...PERSISTING INTO THE EVENING BEFORE DISSIPATING. THINK COVERAGE WILL BE LARGEST ACROSS THE LUMBERTON ZONE AREA. MAV/MET NUMBERS ARE VERY SIMILAR TO MAX TEMPS TODAY...AND SAW NO REASON TO STRAY TOO FAR. FOR MINS... FAVORED A BLEND TOWARD THE SLIGHTLY COOLER MAV NUMBERS. ALSO... POTENTIAL WILL EXIST FOR ADDITIONAL FOG LATE TONIGHT INTO EARLY SUNDAY MORNING. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 AM SATURDAY...THE BIG STORY WILL BE THE CHANGE IN AIR MASS AS THE FRONT WILL BE WELL TO THE SOUTH OF THE AREA SUNDAY MORNING...AT LEAST FROM THE WIND FIELDS. THE CHANGE WILL BE MORE GRADUAL FROM A MOISTURE AND TEMPERATURE STANDPOINT. ENOUGH MOISTURE LINGERS SUNDAY TO WARRANT CHANCE POPS WITH AN EAST TO NORTHEASTERLY FLOW AND SPEED CONVERGENCE THE MAIN FORCING MECHANISMS. THE GFS APPEARS A LITTLE TO AGGRESSIVE WITH THE POPS OR QPF FIELDS PROBABLY THE RESULT OF A VORT MAX THAT IS PRESENT OVER THE SAND HILLS FROM EARLY SATURDAY THROUGH SUNDAY. MONDAY IS A REPEAT OF SUNDAY ALTHOUGH THE POPS WILL BE MORE SUPPRESSED TO THE SOUTH AS VERY DRY MID LEVEL AIR SLOWLY CREEPS INTO THE NORTH CAROLINA COUNTIES DURING THE DAY. HIGH TEMPERATURES ALONG THE COAST WILL REMAIN VERY CLOSE TO ADJACENT WATER TEMPERATURES WHILE INLAND VALUES WILL HAVE THE OPPORTUNITY TO MODIFY A BIT. STILL LIKE THE COOLER MET NUMBERS THROUGHOUT. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 3 AM SATURDAY...LATEST GRIDDED MOS GUIDANCE HAS TRENDED A BIT COOLER AND DRIER SO NUDGED TEMPERATURES DOWN ACROSS THE BOARD SLIGHTLY...OTHERWISE NO CHANGES TO THE EXTENDED FORECAST THIS MORNING. THE LATTER PART OF THE EXTENDED DEPENDS HEAVILY ON THE EVOLUTION OF HANNA. THE LATEST OPERATIONAL GFS HAS SHIFTED DRAMATICALLY WITH THE NORTHERN TURN NOW OCCURRING ON THE EAST SIDE OF THE FLORIDA PENINSULA BRINGING IT UP THE COAST. I SUSPECT WE WILL SEE THIS BOUNCE BACK AND FORTH FOR THE NEXT SEVERAL DAYS. && .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/... MADE SOME SMALL CHANGES TO THE PREVIOUS SET OF TAFS...MAINLY BEEFING UP FOG FORMATION FOR KLBT/KFLO. DEBRIS CLOUDS FROM STORMS EARLIER ARE RIDING NORTH KEEPING MOST OF THE CWA CLOUD FREE. THIS WILL SET UP ANOTHER GOOD RADIATION NIGHT. WINDS AT THE BOUNDARY LAYER WILL BE LIGHT...SO NO HINDER TO FOG FORMATION. IT`S A GOOD BET ALL TERMINALS WILL SEE SOME FOG...WITH THE LOWEST VSBYS AT KFLO/KLBT. LOOK FOR STATIONS TO RISE TO VFR FROM 13-14Z...WITH CU BUILDING ALONG THE SEA BREEZE BOUNDARY. SHOULD BE ENOUGH MOISTURE AND INSTABILITY TO KICK OFF ISOLATED/SCATTERED CONVECTION ALONG THE RESULTANT. LIGHT WINDS THROUGH THE EARLY MORNING HOURS...BECOMING MAINLY SOUTHEAST BY MIDDAY SATURDAY. OUTLOOK THROUGH WEDNESDAY...ISOLATED/SCATTERED THUNDERSTORMS THROUGH SUNDAY...MAINLY AFTERNOON AND EARLY EVENING HOURS. HIGH PRESSURE BUILDS IN MONDAY THROUGH WEDNESDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 3 AM SATURDAY...A WEAK PRESSURE GRADIENT WILL PREVAIL ACROSS THE COASTAL WATERS TODAY LEADING TO LIGHT FLOW. SEAS WILL BE NO MORE THAN 2-3 FT...PRIMARILY COMPRISED OF AN EASTERLY SWELL. THE LATEST WAVEWATCH III OUTPUT INDICATES SWELLS FROM HANNA SHOWING UP IN EARNEST DURING THE SHORT TERM PERIOD. OTHERWISE...SPEEDS AROUND 10 KT...ENHANCED SLIGHTLY BY THE SEA BREEZE CIRCULATION DURING THE DAY. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 AM SATURDAY...REFLECTING THE PUBLIC SECTION...THE DEEP EAST TO NORTHEASTERLY FLOW WILL BE THE MAIN FOCUS FOR THE COASTAL WATERS WITH THE SWELL GENERATED FROM HANNAH THE WILD-CARD. STRONG HIGH PRESSURE BUILDING IN WILL GENERATE WINDS FROM THE NE OF 15-20 KNOTS WITH THE RANGES POSSIBLY INCREASING TO 20-25 KNOTS LATE MONDAY. THE EVENTUAL STRENGTH OF HANNA WILL MODULATE THE LONG PERIOD SWELL AFFECTING THE WATERS. THE GFS APPEARS TO HAVE A DECENT HANDLE ON INITIALIZING THE CYCLONE AND THEREFOR CANT ARGUE WITH THE MAGNITUDE AND TIMING OF THE WAVEWATCH GUIDANCE. THIS BRINGS IN THE SIGNIFICANT SWELL LATE SUNDAY AND INCREASING IT THROUGHOUT MONDAY. LONG TERM /TUESDAY THROUGH WEDNESDAY/... AS OF 3 AM SATURDAY...NO CHANGES TO THE EXTENDED COASTAL WATERS FORECAST THIS MORNING. THE NE FLOW IS EXPECTED TO CONTINUE ALONG WITH THE SWELLS FROM HANNA. && .RIP CURRENTS...LATEST WAVEWATCH OUTPUT FROM THE NAH VERSION SHOWS SWELLS FROM HANNA ARRIVING SUNDAY NIGHT...AND BUILDING THROUGH MONDAY. GIVEN THE TAIL END OF A HOLIDAY WEEKEND WITH MANY PEOPLE EXPECTED TO BE AT THE BEACHES MONDAY THIS COULD BE A POTENTIALLY HAZARDOUS EVENT SETTING UP ALONG THE COAST. FURTHER COMPOUNDING THE PROBLEM IS THAT THERE WILL LIKELY BE SOME TIDAL MODULATIONS IN RIP CURRENT INTENSITY GIVEN THE TIDAL CYCLE WILL BE NEAR THE END OF THE NEW MOON. ULTIMATELY THE DEGREE OF THE RIP CURRENT THREAT WILL DEPEND ON HOW STRONG HANNA AND SUBSEQUENTLY HOW LARGE THE SWELLS WILL BE THAT AFFECT THE COAST. PLAN TO HIGHLIGHT THIS THREAT IN THE HAZARDOUS WEATHER OUTLOOK FOR THE UPCOMING WEEK. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...SRP NEAR TERM...SRP SHORT TERM...SHK LONG TERM...SHK AVIATION...DL/SRP RIP CURRENTS...SRP