000 FXUS62 KILM 241137 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 637 AM EST SAT JAN 24 2015 .SYNOPSIS... LOW PRESSURE WILL CONTINUE TO INTENSIFY AS IT MOVES RAPIDLY NORTH OF THE AREA THIS MORNING. COLDER AND DRIER AIR WILL SWEEP IN BEHIND THE LOW AS IT MOVES UP THE COAST. DRY HIGH PRESSURE WILL BUILD ACROSS THE AREA TONIGHT THROUGH SUNDAY. AN ARCTIC FRONT WILL PUSH ACROSS THE AREA EARLY MONDAY...BRINGING COLDER TEMPERATURES TO THE AREA FOR MUCH OF THE UPCOMING WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 600 AM SATURDAY...LOW PRESSURE WAS IN THE PROCESS OF CONSOLIDATING AND INTENSIFYING ALONG THE CAROLINA COAST. ITS ASSOCIATED WARM FRONT HAD BEGUN TO EDGE BACK TOWARD THE COAST AND WITH THAT...THE WARM AND MORE HUMID AIR WILL LIFT OFFSHORE AND AWAY FROM THE AREA...REPLACED BY MUCH COLDER AIR WHICH COVERED MOST OF THE FORECAST AREA THIS MORNING. THE LAST OF THE WARM SECTOR HUGGING THE COAST WILL QUICKLY RETREAT THROUGH 13-14Z. THE VERY SMALL RISK FOR SEVERE WEATHER ON THE COAST WILL END AS THE WARM SECTOR GETS SHUNTED OFFSHORE. MODELS SHOW SOME ELEVATED INSTABILITY AROUND 850 MB VERY EARLY IN THE PERIOD WITH DEEPER INSTABILITY REMAINING OFFSHORE. MODELS ARE ALSO SHOWING VERY STRONG BULK SHEAR VALUES...AS HIGH AS 50-60 KT THROUGH ABOUT 12Z. A SSW LOW LEVEL JET OF 50-60 KT WILL BE AS LOW AS 1500 FT EARLY THIS MORNING. THUS...EVEN SHALLOW CONVECTION WILL BE CAPABLE OF BRINGING STRONG WIND GUSTS...IN EXCESS OF 40 MPH. GIVEN THE HELICITY VALUES ACROSS THE FORECAST AREA...STILL CAN NOT RULE OUT A VERY BRIEF SPIN-UP OR DAMAGING WIND GUST...BUT THE LACK OF SURFACE BASED INSTABILITY DOES GREATLY REDUCE THE RISK FOR ANYTHING MORE THAN A LONE OR VERY ISOLATED SEVERE THUNDERSTORM/TORNADO. THE NON-ZERO RISK FOR SEVERE WEATHER WILL CONTINUE ALONG THE COAST THROUGH 11-14Z. THE GRADIENT WIND ALONE WILL CONTINUE TO GUST UP TO 25 TO 35 MPH IN THE WARM SECTOR THROUGH AROUND SUNRISE. A TIGHTENING PRESSURE GRADIENT AND INCREASED MIXING ON THE BACK SIDE OF INTENSE LOW PRESSURE MOVING UP THE MID ATLANTIC COAST THIS AFTERNOON WILL MAKE FOR A BRISK AFTERNOON THROUGHOUT WITH WINDS GUSTING TO 25-35 MPH. THE CORRIDOR OF 60+ DEWPOINTS WAS GETTING SHUNTED EASTWARD...IN LINE WITH THE STRONGEST LOW LEVEL JET. THESE VERY HIGH DEWPOINTS GIVEN THE TIME OF YEAR AND NEAR RECORD PRECIPITABLE WATER VALUES WILL BE SHIFTING OFFSHORE THROUGH 14Z. THE RISK FOR PERSISTENT SHOWERS... SOME HEAVY...WILL ALSO BE ENDING THROUGH THE FIRST PART OF THIS MORNING. A STRONG MID-LEVEL SHORTWAVE WILL PIVOT ACROSS THE FORECAST AREA LATE THIS MORNING AND EARLY THIS AFTERNOON. THERE IS A SLIGHT CHANCE OF A SHOWER IN ASSOCIATION WITH THIS FEATURE. THE COLUMN WILL DRY SUBSTANTIALLY IN THE WAKE OF THIS FEATURE...FIRST IN THE MID LEVELS. WILL SHOW POPS FALLING BELOW THRESHOLD MIDDAY/EARLY AFTERNOON INLAND AND EARLY/MID AFTERNOON COAST. SKIES WILL SHOW A CLEARING TREND INLAND MID TO LATE AFTERNOON AND BY EVE AT THE COAST. TONIGHT...PRECIPITABLE WATER VALUES WILL BE DROPPING BELOW 0.25 INCHES...SO AN INCREDIBLE RANGE IN LESS THAN 24 HOURS. A MUCH WEAKER MID-LEVEL TROUGH WILL MOVE ACROSS THE FORECAST AREA LATE TONIGHT. GIVEN THE VERY DRY COLUMN AND INCREASING SUBSIDENCE...WILL BE HARD PRESSED TO SEE EVEN PATCHY CLOUDS WITH THIS DISTURBANCE. HIGHS TODAY WILL BE ACHIEVED THROUGH DAYBREAK ALONG AND E OF THE WARM FRONT WHERE SOME AREAS WILL BE IN THE MID AND UPPER 60S. W OF THE WARM FRONT...TEMPS WILL STRUGGLE TO RISE OUT OF THE 40S AS DRY AND COLD AIR ADVECTION DEVELOP. THIS WILL MAKE FOR AN INTERESTING TEMP CURVE. TEMPS ALONG THE COAST WILL BE FALLING THROUGH THE MORNING BEFORE LEVELING OFF THIS AFTERNOON. DAYTIME HIGHS WILL BE IN THE LOWER TO MID 50S INLAND...UP TO UPPER 50S AND LOWER 60S MORE COASTAL AREAS. AFTERNOON TEMPS WILL BE MAINLY IN THE LOWER TO MID 50S THROUGHOUT. LOWS TONIGHT WILL BE NEAR TO JUST ABOVE FREEZING BY SUN MORNING IN A DRY AND COLD ADVECTION PATTERN. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 300 AM SATURDAY...SUNDAY OFFERS UP SUNSHINE AND SEASONABLE TEMPERATURES AS THE LOCAL PRESSURE PATTERN IS RATHER WEAK AHEAD OF A SLIGHTLY OCCLUDED CLIPPER APPROACHING FROM THE NORTHWEST. CLOUDS INCREASE FROM NW TO SE SUNDAY NIGHT...PERHAPS RAPIDLY...AS THIS SYSTEM APPROACHES. IT DOES NOT APPEAR TO BENEFIT FROM ANY GULF OR ATLANTIC MOISTURE...BUT WILL STILL BRING ISO TO SCT SHOWERS FROM THE STRENGTH OF THE DYNAMICS ALOFT. THE MID LVL TROUGH AXIS IS THROUGH BY 18Z MONDAY BUT SINCE THE SYSTEM IS OCCLUDED THERE MAY BE ENOUGH WRAP AROUND MOISTURE TO NECESSITATE THE LOW POPS FOR THE REMAINDER OF MONDAY...AGAIN STRESSING THAT COVERAGE AND QPF WILL BOTH BE QUITE LOW. THOUGH TECHNICALLY OFFERING A SEASONABLE HIGH TEMPERATURE MONDAY MAY FEATURE FALLING TEMPS IN THE AFTERNOON. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 315 PM FRIDAY...DEEP LOW PRESSURE SYSTEM OVER THE CAROLINAS EARLY MONDAY WILL CARRY AN ARCTIC FRONT EAST ACROSS AND FARTHER AWAY FROM THE AREA THROUGH THE DAY. THE ASSOCIATED UPPER LEVEL TROUGH WILL CROSS THE COAST EARLY MON AFTN WITH A POTENT SHORTWAVE RIDING RIGHT OVER CAPE FEAR. THIS SHOULD SQUEEZE OUT ANY RESIDUAL MOISTURE LEAVING A LOW END CHC OF PCP IN THE FORECAST THROUGH THE AFTN. BY EVENING PLENTY OF COLD AIR WILL WORK ITS WAY INTO THE AREA IN DEEP N-NW FLOW AS WE TAP INTO AN ARCTIC AIR MASS. LOOKS LIKE 850 TEMPS WILL RUN BELOW 0C FROM MON EVE UNTIL THURS MORNING. THE COLDEST TEMPS WILL COME ON TUES AS 850 TEMPS REACH AS LOW AS -7 C. THIS SHOULD KEEP TEMPS IN THE 40S MOST PLACES BOTH TUES AND WED WITH OVERNIGHT LOWS BELOW FREEZING. A COUPLE OF SHORTWAVES WILL MOVE THROUGH THE DEEP TROUGH LOCATED OVER THE EASTERN SEA BOARD KEEPING POTENTIAL FOR SOME CLOUDS THROUGH TUES BEFORE THE AIR MASS DRIES OUT COMPLETELY IN REINFORCING PUSH OF COLD AND DRY AIR. PCP WATER VALUES DROP DOWN FROM CLOSE TO A HALF INCH ON MON DOWN TO NEAR A TENTH OF AN INCH FOR WED AS RIDGE OF HIGH PRESSURE MOVES OVER THE CAROLINAS FROM THE SURFACE UP THROUGH THE UPPER LEVELS. HIGH PRESSURE OVERHEAD ON THURS WILL ALLOW AIR MASS TO MODIFY BRIEFLY AND WARM SLIGHTLY BACK TOWARD NORMAL TEMPS IN THE 50S BUT ANOTHER COLD FRONT WILL MOVE THROUGH ON FRIDAY KNOCKING TEMPS BACK DOWN AGAIN.THIS FRONT LOOKS LIKE IT WILL BE LACKING MOISTURE AND SHOULD SEE MORE IN THE WAY OF CLOUDS THAN PCP. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... AS OF 12Z...CIGS AOB 600-700 FEET WITH TEMPO MVFR/IFR VSBYS IN LIGHT RAIN WILL LIKELY CONTINUE AT KFLO/KLBT THROUGH 16-17Z. THERE COULD BE TEMPO PERIODS OF MVFR CIGS BUT CONFIDENCE IS LOW. THERE IS GOOD CONFIDENCE MVFR CIGS/VFR VSBYS WILL OCCUR BY 17Z AS RAIN ENDS. WINDS WILL BE WNW-NW AROUND 10 KT...BECOMING GUSTY TO AROUND 20 KT TOWARDS 16Z. VFR EXPECTED THIS AFTERNOON. COASTAL TERMINALS WILL HAVE HIGHLY VARIABLE FLIGHT CONDITIONS UNTIL FROPA 13Z AT KCRE/KMYR AND AROUND 14Z AT KILM. GENERALLY MVFR CIGS/MVFR VSBYS IN SHOWERS EXPECTED AHEAD OF THE FRONT WITH GUSTY SW WINDS TO 25-35KT. TEMPO IFR IS LIKELY IN SHOWERS BEFORE FROPA. POST FRONTAL CIGS 400-600 FEET LIKELY WITH MVFR/IFR VSBYS UNTIL SHOWERS TAPER OFF 15-16Z. MVFR EXPECTED 16-17Z WITH VFR IN THE MID-AFTERNOON. WINDS WILL BECOME WNW-NW AROUND 10 KT...BECOMING GUSTY TO AROUND 25 KT TOWARDS 17Z. VFR EXPECTED THROUGH THE REMAINDER OF THE TAF VALID PERIOD. EXTENDED OUTLOOK...VFR ON SUN. SLIGHT CHANCE OF RAIN MON AS A COLD FRONT MOVES ACROSS THE CAROLINAS. VFR AND GUSTY NORTH WINDS TUE/WED. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 600 AM SATURDAY...WILL INITIALIZE WITH A GALE WARNING. ONCE THE GALE WARNING IS LOWERED LATER THIS MORNING...EXPECT SMALL CRAFT ADVISORY CONDITIONS WILL PERSIST INTO TONIGHT. THE STRONGEST WINDS WILL BE THIS MORNING...FROM THE SSW AND SW AT SUSTAINED SPEEDS OF UP TO 35 KT. AS LOW PRESSURE PULLS N OF THE AREA THIS MORNING AND QUICKLY INTENSIFIES...WINDS WILL VEER TO W. THE PRESSURE PATTERN WILL BE SLOW TO RELAX...BUT WIND SPEEDS SHOULD BE DECREASING... ESPECIALLY TONIGHT. THE STRONG AND PERSISTENT WINDS AND PERSISTENT AND SOMETIMES INTENSE CONVECTION HAS BUILT SEAS UP TO 11 TO 15 FT THIS MORNING. AS AN OFFSHORE FLOW DEVELOPS...SEAS WILL BE SUBSIDING...MOST QUICKLY ACROSS THE NEARSHORE WATERS. SEAS MAY NOT DROP BELOW 6 FT ACROSS PORTIONS OF THE OUTER WATERS UNTIL AFTER MIDNIGHT. ANOTHER CONCERN FOR MARINERS WILL BE THE ABNORMALLY LOW WATER LEVELS EXPECTED TO DEVELOP IN THE STRONG OFFSHORE FLOW AND IN THE WAKE OF INTENSE LOW PRESSURE TO OUR N. WATER LEVELS WILL LIKELY DROP TO BETWEEN MINUS 1 AND MINUS 2 FT MLLW AROUND THE TIME OF LOW TIDE LATE THIS AFTERNOON. IF THE WATER LEVEL DROPS BELOW MINUS 2 FT MLLW... THEN A LOW WATER ADVISORY WILL BE ISSUED. WE WILL ADDRESS THIS WITH AT LEAST A MARINE WEATHER STATEMENT LATER THIS MORNING. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 300 AM SATURDAY...CONDITIONS CONTINUE TO IMPROVE SUNDAY FOLLOWING RATHER ACTIVE NEAR TERM WEATHER AS THE CYCLONIC FLOW ASSOC WITH BIG STORM IN NEW ENGLAND FINALLY MOVES OFFSHORE AND OUT OF OUR AREA. WHAT REMAINS IS LIGHTER FLOW THAT BACKS IN DIRECTION AS THE DAY WEARS ON IN RESPONSE TO A SYSTEM APPROACHING FROM THE NORTHWEST. BY SUNDAY NIGHT FLOW WILL TURN TO SW AND PICK UP BUT NOT QUITE TO CAUTIONARY LEVELS. MULTI-CENTERED LOW PRESSURE MOVES ACROSS EARLY MONDAY WITH A W TO NW COOL SURGE THEREAFTER. LATEST GUIDANCE A LITTLE LESS AGGRESSIVE WITH THE ENSUING WINDS AND SEAS AND AN ADVISORY PROBABLY NOT GOING TO MATERIALIZE EVEN THOUGH SOME GUSTS TO 25KT APPEAR POSSIBLE GIVEN THE WELL-ALIGNED LOW LEVEL FLOW. LONG TERM /MONDAY THROUGH WEDNESDAY/... AS OF 315 PM FRIDAY...COLD FRONT WILL MOVE THROUGH THE WATERS EARLY MONDAY WITH A DEEP COLD NW TO N FLOW SETTING UP THROUGH MID WEEK. SHOULD SEE GUSTY NW WINDS ON MONDAY UP TO 15 TO 20 KTS. SEAS AROUND 3 TO 5 FT WILL KICK SEAS UP BRIEFLY BUT THE OFF SHORE COMPONENT TO THE FLOW WILL KEEP GREATEST SEAS OFF SHORE. WINDS AND SEAS SHOULD DIMINISH SOME THROUGH TUES AS WINDS VEER MORE TO THE NORTH AND GRADIENT SLACKENS...BUT A SECONDARY PUSH OF COLD AND DRY AIR WILL COME TUES NIGHT WITH HIGH PRESSURE BUILDING IN THROUGH WED. THE TIGHTENED GRADIENT WILL KEEP WINDS UP TO 15 TO 20 KTS AGAIN TUES NIGHT INTO WED WITH SEAS APPROACHING SCA THRESHOLDS. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...GALE WARNING UNTIL NOON EST TODAY FOR AMZ250-252-254-256.
Posted on: Sat, 24 Jan 2015 11:54:58 +0000