Area Forecast Discussion
Issued by NWS Wilmington, NC

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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 260800 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 400 AM EDT SAT JUL 26 2014 .SYNOPSIS...
-- Changed Discussion --
HIGH PRESSURE WILL BUILD OVER THE REGION BRINGING HOT AND HUMID CONDITIONS OVER THE WEEKEND AND MONDAY. ANOTHER UNUSUALLY STRONG COLD FRONT MAY BRING STRONG TO SEVERE THUNDERSTORMS LATE MONDAY. COOLER AND DRIER WEATHER WILL RETURN ON TUESDAY AND LAST THROUGH MUCH OF NEXT WEEK.
-- End Changed Discussion --
&& .NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
AS OF 330 AM SATURDAY...BEWARE THE NW FLOW!...A BATTLE CRY THATS BEEN USED HERE WHEN FLOW ALOFT IS FROM THE NW AND VARIOUS MODEL GUIDANCE IS SAYING VERY LITTLE CHANCE FOR CONVECTION. IN FACT...VARIOUS MODEL MOS GUIDANCE KEEPS POPS EVEN BELOW ISOLATED CHANCE. WITH THAT SAID...ITS DIFFICULT TO BEGIN WITH TO INDICATE A POP-LESS FORECAST FOR THIS TIME OF THE YEAR. THE SEA BREEZE AND PIEDMONT TROF SHOULD PROVIDE ENOUGH FORCING TO ENABLE CONVECTION INITIATION THIS AFTERNOON. MODELS DO ILLUSTRATE MUCH NOISE IN THE MID-LEVELS WITH REFERENCE TO THE MOVEMENT OF S/W TROFS OR VORTS ACROSS THE FA THRU TONIGHT. IN ADDITION...THEY ALSO SHOW NVA AND SUBSIDENCE THAT ALSO PASSES OVERHEAD AT VARIOUS TIMES THROUGH TONIGHT. LOOKING AT SOUNDING DATA PARTICULARLY HOURLY NAMBUFR SOUNDINGS...AN IDENTIFIABLE WEAK TO MODEST TEMP INVERSION PROGGED TO OCCUR ALOFT...MAINLY BETWEEN 700 AND 600 MB. THIS WOULD PUT A DAMPER ON CONVECTION INITIATION. WITH ALL THIS SAID...WILL INDICATE ISOLATED POPS ACROSS PORTIONS OF THE FA THIS AFTERNOON AND EVENING. AS FOR TEMPS...MODEL MOS GUIDANCE INDICATES AROUND 90 FOR MAXES...INCLUDING THE BEACHES. GIVEN THE DOWNSLOPE TRAJECTORY IN THE WIND FIELD ALOFT...WILL GO A DEGREE OR 3 HIGHER THAN MODEL MOS GUIDANCE CONSENSUS. THIS MEANS WIDESPREAD 90 DEGREE READINGS TODAY...EXCEPT THE IMMEDIATE BEACHES WHERE MID-UPPER 80S TO PREVAIL. WILL REMAIN BELOW HEAT ADVISORY CONCERNS TODAY...BUT FOR THE NEXT 2 DAYS THIS WILL NOT BE THE CASE.
-- End Changed Discussion --
&& .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
-- Changed Discussion --
AS OF 3 AM SATURDAY...START OF NEXT WEEK WILL BE QUITE WARM WITH HIGHS ON BOTH SUN AND MON RUNNING WELL INTO THE 90S. MID LEVEL RIDGE WILL EXTEND EAST FROM THE SOUTHWESTERN CONUS SUN. FORECAST SOUNDINGS SHOW CAPPING AROUND 800 MB...A RESULT OF SUBSIDENCE ON THE PERIPHERY OF THE 5H RIDGE. CAPPING ALONG WITH DEEP WESTERLY FLOW WILL MAKE EVEN ISOLATED CONVECTION HARD TO COME BY. CANNOT RULE OUT AN ISOLATED SHORT LIVED SHOWER ALONG OR JUST BEHIND THE SEA BREEZE BUT NOTHING WORTH CARRYING A POP ABOVE 10%. 850 TEMPS IN THE 20C TO 22C RANGE AND LACK OF MUCH CLOUD COVER/CONVECTION WILL PUSH HIGHS INTO THE MID TO UPPER 90S AREA WIDE. DESPITE LIMITED CLOUD COVER SUN NIGHT LOWS WILL BE KEPT IN THE UPPER 70S TO AROUND 80 BY STRENGTHENING LOW LEVEL JET. STRONG COLD FRONT WILL CROSS THE AREA ON MON WITH IMPRESSIVE 5H TROUGH THE DRIVING FACTOR. BEST PRECIP CHANCES DURING THE PERIOD WILL BE ON MON...AHEAD OF THE COLD FRONT WHEN PRECIPITABLE WATER VALUES WILL BE AROUND 2 INCHES. MON IS ALSO SHAPING UP TO BE A HOT DAY WITH 850 TEMPS ONCE AGAIN IN THE LOWER 20C RANGE. HIGHS IN THE MID 90S COMBINED WITH DEWPOINTS IN THE LOW 70S WILL NOT ONLY PRODUCE HEAT INDEX VALUES AT OR ABOVE 105F...LIKELY WARRANTING A HEAT ADVISORY...BUT WILL SET THE STAGE FOR AFTERNOON CONVECTION. MID LEVEL COOLING COMBINED WITH STRONG LOW LEVEL CONVERGENCE ALONG THE FRONT AND VERY WARM LOW LEVELS IS LIKELY TO PRODUCE WIDESPREAD SHOWERS AND THUNDERSTORMS. WHILE IT APPEARS THE CORE OF THE UPPER LEVEL JET WILL REMAIN NORTH OF THE AREA STRONG TO SEVERE CONVECTION REMAINS A POSSIBILITY BASED ON THERMODYNAMIC PROFILES MON AFTERNOON/EVENING AND SPC HAS PLACED MUCH OF THE FORECAST AREA WITHIN A SLIGHT RISK AREA FOR DAY 3.
-- End Changed Discussion --
&& .LONG TERM /TUESDAY THROUGH FRIDAY/...
-- Changed Discussion --
AS OF 3 AM SATURDAY...NOTICEABLE AIR MASS CHANGE FROM MON AFTERNOON TO TUE AFTERNOON AS BOTH HEAT AND HUMIDITY WILL BE LACKING. PRECIPITABLE WATER VALUES DROP DOWN TO AROUND AN INCH TUE WHILE NORTHERLY FLOW USHERS COOLER AIR INTO THE REGION. TROUGH AXIS REMAINS JUST WEST OF THE AREA FOR THE PERIOD WITH GENERALLY DEEP WESTERLY FLOW KEEPING MID LEVELS DRY. GFS/ECMWF BOTH SHOW A SHORTWAVE CROSSING THE AREA TUE NIGHT INTO WED BUT DIFFER ON ITS STRENGTH AND IMPACT. WILL NOT BE ADDING ANY PRECIP CHANCES GIVEN THE UNFAVORABLE ENVIRONMENT AND DIFFICULTY IN ACCURATELY DEPICTING SUCH FEATURES IN THE EXTENDED PERIOD. FORECAST SOUNDINGS DO NOT SHOW MUCH OF AN INCREASE IN DEEP MOISTURE THROUGH THE PERIOD...PWATS BARELY EXCEED 1.25 INCHES DURING THE PERIOD...SO DIURNAL CONVECTION WILL BE SCARCE. CANNOT RULE OUT SOME ISOLATED STORMS ANY GIVEN AFTERNOON BUT DO NOT THINK A MENTIONABLE POP IS WARRANTED. BEST CHANCES WOULD BE NEAR THE COAST...ALONG OR JUST BEHIND THE SEA BREEZE BUT EVEN HERE COVERAGE ABOVE 20% IS UNLIKELY. TEMPERATURES WILL REMAIN BELOW CLIMO THROUGH THE PERIOD WITH POTENTIAL FOR SOME RADIATIONAL COOLING OVERNIGHT DURING THE MIDDLE OF THE WEEK.
-- End Changed Discussion --
&& .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/... AS OF 06Z...FEW LEFTOVER CONVECTIVE DEBRIS CLOUDS OTHERWISE RADIATIONAL COOLING WILL RULE THE AM HOURS. RESIDUAL LOW LEVEL MOISTURE WILL RESULT IN LOW STRATUS CLOUD DECKS...MAINLY AFFECTING THE INLAND TERMINALS. FOG WILL ALSO BECOME A HINDRANCE TO AVIATORS WITH GUIDANCE POINTING TOWARDS DENSE FOG ESPECIALLY ACROSS THE INLAND TERMS. BY 12Z AND AFTER A COUPLE HOURS OF INSOLATION...THE FOG SHOULD QUICKLY DISSIPATE. FOR SATURDAY MIDDAY THROUGH EARLY EVENING...2 SFC BASED FEATURES...SEA BREEZE AND THE PIEDMONT TROF... WILL BE THE DRIVING FORCE FOR POSSIBLE ISOLATED CONVECTION. HOWEVER...PROGGED SUBSIDENCE ALOFT WILL KEEP THUNDERSTORM ACTIVITY LIMITED IN AREAL COVERAGE AND IN STRENGTH. EXTENDED OUTLOOK...SHOWERS/TSTMS/TEMPO MVFR POSSIBLE SUNDAY AND MONDAY. OTHERWISE EXPECT VFR. && .MARINE...
-- Changed Discussion --
NEAR TERM /THROUGH TONIGHT/... AS OF 330 AM SATURDAY...THE OLD STALLED OUT FRONTAL BOUNDARY ACROSS PORTIONS OF THE LOCAL WATERS TODAY WILL FINALLY DISSIPATE AS IT BECOMES ABSORBED WITHIN THE SYNOPTIC FLOW. THE PIEDMONT TROF ACROSS THE CENTRAL CAROLINAS IS PROGGED TO BECOME STRONGER THRU TONIGHT. RIDGING FROM THE OFFSHORE ATLANTIC HIGH WILL EXTEND WESTWARD JUST SOUTH OF THE AREA WATERS. THE SFC PRESSURE PATTERN AND GRADIENT BETWEEN THESE 2 FEATURES WILL PRODUCE A TIGHTENING SFC PG THAT YIELDS ATLEAST 15 KT FOR SPEEDS LATER TODAY AND TONIGHT. A SFC PRESSURE PATTERN THAT WILL TRANSITION TO A SW FLOW THIS AFTERNOON AND TONIGHT. SIGNIFICANT SEAS INITIALLY WILL BE DOMINATED BY A 2 FOOT ESE GROUND SWELL. LATER THIS AFTERNOON AND NIGHT...LOCALLY PRODUCED WIND WAVES WILL INCREASE IN SIZE AND COVERAGE AND LIKELY BECOME THE MORE DOMINATE OF THE 2. DOMINATE PERIODS AROUND 7 SECONDS. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 AM SATURDAY...INCREASING SOUTHERLY FLOW AHEAD OF STRONG COLD FRONT WILL LIKELY RESULT IN HEADLINES FOR ALL ZONES LATER SUN NIGHT AND MON. NATURE OF THE HEADLINES IS AS OF YET UNDETERMINED. IT MAY END UP THAT SCEC IS NEEDED SUN NIGHT AND THEN SCA MON AND PART OF MON NIGHT. SOUTHWEST FLOW 15 TO 20 KT SUN WILL INCREASE TO A SOLID 20 KT SUN NIGHT AND MON. COMBINATION OF PROLONGED SOUTHWEST FLOW AND INCREASE IN SPEEDS BUILDS SEAS FROM 3 TO 4 FT AT THE START OF THE PERIOD TO 4 TO 6 FT ON MON. OFFSHORE FLOW DEVELOPS IN THE WAKE OF THE FRONT LATER MON NIGHT WITH SPEEDS DROPPING TO 10 KT OR LESS BY TUE MORNING. OFFSHORE COMPONENT AND DECREASE IN SPEEDS LATE MON NIGHT WILL RESULT IN SEAS FALLING TO 3 TO 4 FT BY THE END OF THE PERIOD. LONG TERM /TUESDAY THROUGH WEDNESDAY/... AS OF 3 AM SATURDAY...HIGH PRESSURE WILL BE SLOW TO BUILD IN BEHIND THE DEPARTING COLD FRONT TUE INTO WED...LEAVING A WEAK AND ILL DEFINED GRADIENT OVER THE WATERS DURING THE FIRST HALF OF THE PERIOD. WINDS WILL BE VARIABLE WITH SPEEDS UNDER 10 KT TUE INTO WED. INFLUENCE OF SURFACE HIGH OVER THE MIDWEST BECOMES MORE PRONOUNCED ON WED WITH 10 TO 15 KT NORTHEAST FLOW DEVELOPING BY AFTERNOON. SEAS WILL TREND DOWN TUE AND TUE NIGHT BEFORE INCREASING SLIGHTLY ON WED INTO WED NIGHT AS WIND FIELD BECOMES MORE DEFINED.
-- End Changed Discussion --
&& .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...DCH SHORT TERM...III LONG TERM...III AVIATION...DCH

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