Area Forecast Discussion
Issued by NWS Wilmington, NC

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS62 KILM 270414 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 1214 AM EDT WED APR 27 2016 .SYNOPSIS... WARM WEATHER IS EXPECTED THROUGH FRIDAY AHEAD OF AN APPROACHING COLD FRONT. WARM AND UNSTABLE AIR AHEAD OF THE FRONT WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS THURSDAY AND THURSDAY NIGHT WITH DRIER AND MILD CONDITIONS FRIDAY. HIGH PRESSURE WILL BUILD IN ON SATURDAY BRINGING A BIT OF A COOL DOWN. A RAINY START TO THE MONTH OF MAY IS LOOKING MORE LIKELY...AS A LOW PRESSURE SYSTEM IMPACTS THE AREA LATE SUNDAY THROUGH TUESDAY OF NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 928 PM TUESDAY...A CAPPED ATMOSPHERE REMAINS OVERHEAD OF NE SC AND SE NC...BUT CHANGES TO TAKE PLACE OVERNIGHT INCLUDE H9-H7 MOISTURE ADVECTION INTO EARLY WEDNESDAY AND DECREASING SUBSIDENCE ALOFT. VAPOR ANIMATIONS APPEAR TO SUPPORT BOTH OF THESE IMMINENT OCCURRENCES. WHILE NO POPS OR EVEN SIGNIFICANT CLOUD COVER ARE PLANNED FOR THE OVERNIGHT PERIOD...THE TRANSITION WILL SUPPORT MORE ACTIVE WEATHER LATER INTO WEDNESDAY. MOST RECENT KLTX VWP DATA SHOW 35 KT SW WIND AT 1 KFT RIGHT ON THE EXPECTED TIME FOLLOWING NIGHTFALL. THIS ELEMENT WILL MAINTAIN PERHAPS ENOUGH WIND NEAR THE SURFACE TO PREVENT FOG OR MIST FROM EVER GAINING A FOOTHOLD OVERNIGHT...WHILE AIDING MILDER MINIMUM TEMPERATURES THAN RECENT MORNINGS. 62-66 INLAND AND 66-69 AT THE COAST REMAINS THE TARGETED RANGE. SEA SURFACE TEMPERATURES ARE NEARING 70 DEGREES...AND THIS WILL INFLUENCE MINIMUMS DURING BLUSTERY NIGHT PERIODS OF ONSHORE WIND...SIMILAR TO TONIGHTS OVERNIGHT PERIOD. && .SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/... AS OF 315 PM TUESDAY...WARM AND HUMID CONDITIONS TO CONTINUE THIS PERIOD AS BERMUDA HIGH PRESSURE PERSISTS OFFSHORE. AT THE SAME TIME...A COLD FRONT WILL BE SLOWLY DROPPING SOUTH...AND THESE FEATURES COMBINES WILL CREATE INCREASING CHANCES FOR TSTMS. EXPANSIVE AREA OF HIGH PRESSURE OFFSHORE WILL CONTINUE TO RIDGE BACK INTO THE CAROLINAS WEDNESDAY AND THURSDAY...ONLY BECOMING SLOWLY DISPLACED BY A COLD FRONT THURSDAY NIGHT. RETURN FLOW AROUND THIS HIGH WILL DRIVE INCREASING WARMTH AND HUMIDITY...BUT THIS WILL COME WITH THE COST OF PROMOTING BETTER CONVECTION CHANCES EACH DAY. ON WEDNESDAY...HIGHS WILL SOAR INTO THE MID AND EVEN UPPER 80S AWAY FROM THE COAST...WHILE A SEA BREEZE WILL KEEP THE BEACH COMMUNITIES 5- 10 DEGREES COOLER. THE COMBINATION OF THESE WARM TEMPS AND DEWPOINT VALUES IN THE 60S WILL CREATE AMPLE INSTABILITY...FORECAST TO BE AROUND 1500 J/KG...AND AIR MASS TYPE PULSE CONVECTION IS POSSIBLE WEDNESDAY. THE SEA BREEZE AND PIEDMONT TROUGH WILL LIKELY SERVE AS THE INITIAL FOCUS FOR STORMS...BUT ANY BOUNDARIES COULD DRIVE STORMS ON WEDNESDAY. FORECAST SOUNDINGS REMAIN PRETTY DRY ABOVE 700 MB...SO DO NOT EXPECT WIDESPREAD OR STRONG STORMS...BUT AT LEAST SCATTERED COVERAGE IS LIKELY. MOST OF THIS ACTIVITY WILL WANE AFTER DARK AS IT IS PRIMARILY DIURNALLY FORCED...BUT A WARM NIGHT WILL REMAIN AS LOWS FALL ONLY INTO THE MID 60S. A SIMILAR DAY FORECAST FOR THURSDAY...BUT MORE WIDESPREAD CONVECTION IS FORECAST AS THE AFOREMENTIONED FRONT DROPS FURTHER SOUTH AND MID- LEVEL HEIGHTS DROP LEADING TO STEEPER LAPSE RATES. TEMPS ONCE AGAIN IN THE LOW/MID 80S WILL CREATE AMPLE INSTABILITY OF 1500-200 J/KG WHICH WILL FUEL STORMS ON THURSDAY. THE TYPICAL BOUNDARIES WILL AGAIN BE FAVORED DURING THE AFTN...BUT AS THE FRONT DROPS SLOWLY INTO THE AREA THURSDAY EVE AND NIGHT...CONVECTION COULD BECOME MORE WIDESPREAD AND LAST WELL AFTER DARK. SPC HAS THE AREA IN A MARGINAL RISK FOR THE SWODY3...BUT OTHER THAN LARGE CAPE VALUES THE OVERALL SEVERE PARAMETERS ARE LOW...AND ATTM DO NOT EXPECT MUCH SEVERE POTENTIAL...BUT AN ISOLATED WET MICROBURST IS POSSIBLE THANKS TO A SUBTLE INVERTED-V IN THE INCREASINGLY SATURATED ENVIRONMENT. COLD FRONT WILL BE MOVING OFFSHORE AT THE END OF THE PERIOD...BUT LOWS WILL AGAIN REMAIN WARM...FALLING ONLY INTO THE MID 60S...LOW 60S WELL NORTH. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 315 PM TUESDAY...THE MID LEVEL PATTERN WILL CONTINUE TO BE HIGHLY AMPLIFIED AND SLOW MOVING...NOT SURPRISING FOR LATE APRIL IN THE TRANSITION SEASON FROM SPRING TO SUMMER. LOW PRESSURE WILL BE LOCATED OVER THE SOUTHWEST WITH A ZONAL FLOW TO THE EAST. THE FLOW SLOWLY BECOMES SOUTHWEST ACROSS OUR AREA BY TUESDAY AS THE LOW OPENS UP AND MEANDERS EAST. AS FOR THE SURFACE FEATURES...HIGH PRESSURE BUILDING IN FROM THE NORTHEAST SHOULD KEEP FRIDAY AND SATURDAY DRY. BY SUNDAY HIGHER THETA-E AIR ARRIVES AND WITH MINIMAL FORCING...SEA BREEZE AND THE PIEDMONT TROUGH IT IS ENOUGH TO WARRANT SLIGHT CHANCE POPS. BETTER MID LEVEL FORCING ALONG WITH THE PREVIOUS ELEMENTS WARRANT HIGHER POPS MONDAY. SOME UNCERTAINTY FOR TUESDAY AS THE GFS IS MORE PROGRESSIVE IN CLEARING THING OUT WHILE THE ECMWF MOVES ANOTHER SYSTEM ACROSS. MAINTAINED SHOWERS IN THE FORECAST FOR NOW BUT THIS IS SUBJECT TO CHANGE. TEMPERATURES SHOULD BE ABOVE NORMAL MOST OF THE PERIOD. WARMEST FRIDAY BEFORE THE HIGH BUILDS IN AND THE MOISTURE RETURNS. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
AS OF 05Z...EXPECT A HIGH LIKELIHOOD OF VFR THROUGH THE 06Z TAF ISSUANCE PERIOD. CLEAR SKIES EARLY THIS MORNING WITH MID/HIGH TSTM DEBRIS CLOUDS DROPPING SE MAY SPREAD ACROSS THE TERMINALS DURING THE PRE-DAWN HOURS. STRATOCU 4-5K MAY ALSO BEGIN TO DEVELOP AS DAWN APPROACHES. ALL TAF SITES WILL SEE SW WINDS AT 5 TO 10 KT WITH OCNL GUSTS TO 15 KT IN RESPONSE TO A SW LLJ AT 30-35 KT AT 1100 TO 1400 FT AGL. APPEARS SITES WILL REMAIN JUST BELOW LLWS CRITERIA ATTM...BUT THIS MAY CHANGE AS SURFACE WINDS DECREASE SLIGHTLY TOWARD DAYBREAK WED...AND ALSO VEER TO THE SW-WSW AT 5 TO 10 KT. THE SEA BREEZE WILL AGAIN DEVELOP BY NOON AT THE IMMEDIATE COASTAL TERMINALS...REACHING ILM BY 18Z...OVERALL WINDS BACKING TO THE SSW AND GUSTING TO 20 KTS. ALONG AND WEST OF THE SEA BREEZE DURING THIS AFTERNOON...80+ DEGREE TEMPS AND DEWPOINTS IN THE 60S WILL CREATE AMPLE INSTABILITY FOR POSSIBLE AIR MASS PULSE CONVECTION. HOWEVER...IT REMAINS TOO ISOLATED TO MENTION IN KFLO/KLBT TAFS ATTM. PRECIPITATION CHANCES SHOULD DECREASE RAPIDLY AFTER SUNSET. EXTENDED OUTLOOK...ISOLATED CONVECTION POSSIBLE WED AFTERNOON AND EVENING. INCREASED CHANCES FOR SCATTERED CONVECTION THURSDAY INTO FRIDAY DUE TO A BACK-DOOR COLD FRONT DROPPING SOUTHWARD. OTHERWISE EXPECT VFR.
-- End Changed Discussion --
&& .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 928 PM TUESDAY...WIND-SPEEDS ARE SHOWING AN INCREASE AS THE NOCTURNAL SW JET GEARS UP. IN THAT SSTS HAVE WARMED OVER THE LAST SEVERAL DAYS...ADDED MIXING TO THE SEA SURFACE SHOULD SUPPORT GUSTS TO 20 KT OVERNIGHT. SEA-HEIGHTS HOWEVER SHOULD HOLD AROUND 3 FEET IN A MIX OF LONG PERIOD EAST WAVES EVERY 10 SECONDS AND MODERATE SW SHORT-CRESTED WIND-WAVES. NO SIGNIFICANT CHANGES AT THIS TIME...THE PREVIOUS DISCUSSION FOLLOWS. E WAVE 2-3 FT EVERY 9 SECONDS WERE FANNING ASHORE. THIS WILL REMAIN NEARLY UNCHANGED OVERNIGHT PERHAPS BECOMING DOMINANT AT 10-11 SECOND INTERVALS. NO TSTMS OR RESTRICTIONS TO VSBY EXPECTED ON THE 0-20 NM WATERS. LIGHT TO MODERATE SW CHOP WILL PREVAIL OVERNIGHT. NO CHANGES TO THE MARINE FORECAST...ALTHOUGH WILL NEED TO REASSESS IF 20 KT GUSTS SHOULD BE INCLUDED FOR THE ENTIRETY OF THE OVERNIGHT PERIOD AS THE LOW LEVEL WIND JET INCREASES. MILDER SSTS WILL PROMOTE THE HIGHER WIND. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 315 PM TUESDAY...LARGE HIGH PRESSURE OFFSHORE WILL BE THE DOMINANT INFLUENCE ON THE WATERS THIS PERIOD AS IT DRIFTS VERY SLOWLY TO THE EAST. THIS WILL DRIVE PERSISTENT SW WINDS OF AROUND 15 KTS...INCREASING TO 20 KTS AT TIMES THROUGH THURSDAY NIGHT...AS A COLD FRONT APPROACHING FROM THE NORTH PINCHES THE GRADIENT. THIS FRONT WILL BE ALONG OR JUST NORTH OF THE NORTHERN EDGE OF THE WATERS THURSDAY NIGHT WITH THE ASSOCIATED WIND SHIFT TO THE NW EXPECTED BEYOND THE SHORT TERM. SEAS WILL BE 3-4 FT MUCH OF THE PERIOD WITH A 9-10 SEC SE SWELL AND 5 SEC SW WIND WAVE PRODUCING THE SPECTRUM. LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 315 PM TUESDAY...OVERALL SOMEWHAT MANAGEABLE CONDITIONS FOR THE MARINE COMMUNITY FOR THE EXTENDED ALTHOUGH NOT IDEAL. A BRIEF WESTERLY FLOW WILL BE IN PLACE INITIALLY WITH LIGHT AND VARIABLE WINDS LATER FRIDAY INTO SATURDAY MORNING. A BETTER DEFINED NORTHEAST FLOW DEVELOPS LATER SATURDAY IN A 10-15 KNOT RANGE. BY LATER SUNDAY AN ONSHORE FLOW WILL DEVELOP. THE HIGHEST WIND SPEEDS SHOULD OCCUR EARLY FRIDAY AROUND 15 KNOTS. THE SEAS WILL BE MANAGEABLE THROUGHOUT WITH THE LIGHT WIND FIELDS. EXPECT A MOSTLY 2-4 FOOT RANGE WITH IF ANYTHING EVEN LOWER VALUES. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...SHK NEAR TERM...JDW SHORT TERM...JDW LONG TERM...SHK AVIATION...DCH/MRR

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.