463  
FXUS62 KILM 201735  
AFDILM  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE WILMINGTON NC  
135 PM EDT SAT APR 20 2019  
   
SYNOPSIS
 
 
LOW PRESSURE ALOFT OVER THE TENNESSEE VALLEY WILL SLOWLY CROSS  
THE MID-ATLANTIC STATES SUNDAY THEN MOVE OFFSHORE MONDAY. HIGH  
PRESSURE WILL BUILD OVER THE SOUTHEAST FROM THE WEST LATER TODAY  
THROUGH SUNDAY, SHIFTING OVERHEAD MONDAY. THE HIGH WILL LINGER  
THROUGH THE MIDDLE OF THE WEEK BEFORE SHIFTING OFFSHORE LATE IN  
THE WEEK AS THE NEXT SYSTEM APPROACHES FROM THE WEST.  
 

 
   
NEAR TERM /THROUGH SUNDAY/
 
 
AS OF 10 AM SATURDAY...SHORTWAVE AND ASSOCIATED MOISTURE  
ROTATING AROUND THE BASE OF THE 5H LOW, OVER THE TN VALLEY THIS  
MORNING, WILL LEAD TO SCATTERED SHOWERS THIS AFTERNOON. THE  
QUESTION IS WILL THESE SHOWERS MOVE INTO THE FORECAST AREA OR  
SKIRT THE AREA TO THE NORTHWEST. DID INTRODUCE A SLIGHT CHANCE  
POP FOR NORTHWEST CORNER OF THE FORECAST AREA WITH THE UPDATE  
BASED ON CURRENT SATELLITE/RADAR TRENDS. FURTHER EXPANSION OF  
SHOWER COVERAGE MAY BE REQUIRED WITH THE EARLY AFTERNOON UPDATE.  
OTHER THAN FIGURING OUT HOW CLOSE THE COLD POOL AND MOISTURE  
WILL BE TO THE AREA THE FORECAST IS PRETTY STRAIGHT FORWARD.  
STEEP LOW LEVEL LAPSE RATES AND INCREASE AFTERNOON CLOUD,  
ESPECIALLY INLAND, WILL LIMIT WARMING TODAY AND, COUPLED WITH  
COLD ADVECTION, WILL KEEP TEMPERATURES BELOW TO WELL BELOW  
CLIMO.  
 

 
   
SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/
 
 
AS OF 300 AM SATURDAY...THERMAL ADVECTION TURNS NEUTRAL  
SUNDAY NIGHT BUT AFTER THE COOL PRECEDING DAY LOW TEMPERATURES  
WILL END UP A FEW DEGREES BELOW CLIMATOLOGY. THIS HOLDS TRUE  
HEADING INTO MONDAY BUT SOLAR MODIFICATION OF THE AIRMASS WILL  
BRING AN AFTERNOON THAT IS A FEW DEGREES ABOVE CLIMO. THERE  
WILL BE SOME WEAK WARM ADVECTION MONDAY NIGHT BUT WITH THE HIGH  
CENTER SO CLOSE IT WILL NOT MIX TO THE SURFACE. SO ONCE AGAIN  
MONDAY NIGHT TEMPS RIGHT NEAR NORMAL.  
 

 
   
LONG TERM /TUESDAY THROUGH FRIDAY/
 
 
AS OF 300 AM SATURDAY...SURFACE HIGH PRESSURE THAT MOVES EAST  
ACROSS THE AREA TUESDAY INTO WEDNESDAY WILL BE WEAK AND POORLY  
DEFINED KEEPING WINDS VERY LOW AND WARM ADVECTION SOMEWHAT  
MINIMIZED. THE WARMING TREND ONGOING WILL BE MORE TIED TO SOLAR  
MODIFICATION OF THE AIRMASS. THURSDAY NO LONGER APPEAR TO OFFER  
THE CHANCE FOR BACKDOOR COLD FRONT RELATED SHOWERS AS THE  
BOUNDARY NOW STAYS MUCH FURTHER TO OUR NORTH. MOISTURE WILL BE  
INCREASING HOWEVER AS A SOUTHERN BRANCH FEATURE APPROACHES FROM  
THE WEST. THIS FEATURE WILL INTRODUCE RAIN CHANCES ON FRIDAY.  
 

 
   
AVIATION /18Z SATURDAY THROUGH THURSDAY/
 
 
AS OF 18Z...UPPER LOW WILL MOVE SLOWLY NORTHEAST THROUGH THE  
FORECAST PERIOD. STEEP LAPSE RATES HAVE SPAWNED A LOT OF CU. ANY  
PRECIP WILL LIKELY BE NORTH OF OUR CWA, HOWEVER LBT COULD SEE A  
BRIEF SHOWER AROUND MAX HEATING. WINDS WILL BE PREDOMINATELY  
OFFSHORE. LIGHT WINDS TONIGHT AND SUNDAY.  
 
EXTENDED OUTLOOK...VFR CONDITIONS THRUOUT THE EXTENDED AS THE CENTER  
OF HIGH PRESSURE PARKS ACROSS THE EASTERN CAROLINAS.  
POTENTIAL FOR MVFR FROM MORNING FOG TUE AND WED MORNINGS.  
 

 
   
MARINE
 
 
AS OF 10 AM SATURDAY...STRONG SMALL CRAFT ADVISORY CONTINUES FOR  
ALL ZONES WITH POTENTIAL FOR GUSTS APPROACHING 30 KT THIS  
AFTERNOON. WINDS WILL GRADUALLY WEAKEN LATE TODAY INTO TONIGHT  
AS COLD ADVECTION ABATES AND GRADIENT RELAXES. ONLY MINIMAL  
CHANGES WITH MORNING UPDATE.  
 
WIND SPEEDS WILL DROP BELOW SCA THRESHOLDS TONIGHT AND  
CONTINUING THE DIMINISHING TREND ON SUN. SIGNIFICANT SEAS WILL  
BE SLOW TO SUBSIDE GIVEN THE SWELL GENERATED JUST OFFSHORE  
BLEEDING INTO THE LOCAL WATERS. SW TO WSW WIND DRIVEN WAVES WILL  
MESH ON TOP OF THIS SWELL. SCA THRESHOLD SEAS WILL PERSIST THRU  
TONIGHT AND POSSIBLY A GOOD PORTION OF SUN.  
 
ADVISORY FLAGS SHOULD BE ABLE TO BE DROPPED SUNDAY NIGHT AS HIGH  
PRESSURE BUILDING IN BRINGS LIGHT NW WINDS AND DECREASING SEAS.  
WITH THE HIGH BOTH POORLY DEFINED AND MOVING OVERHEAD MONDAY AND  
MONDAY NIGHT WINDS WILL BE CAPPED AT 10KT AND EXHIBIT SOME  
INCONSISTENCY IN DIRECTION.  
 
HIGH PRESSURE WILL BE FOUND OFF THE COAST THROUGH THE PERIOD.  
THIS WILL PROMOTE A GENERALLY SOUTHWESTERLY FLOW. THE HIGH WILL  
REMAIN WEAK AND KEEP WINDS AROUND JUST 10KT. SEAS WILL AVERAGE  
2-3 FEET.  
 

 
   
ILM WATCHES/WARNINGS/ADVISORIES
 
 
SC...NONE.  
NC...HIGH RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR NCZ106-  
108.  
HIGH RIP CURRENT RISK UNTIL 9 PM EDT THIS EVENING FOR NCZ110.  
BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR NCZ110.  
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EDT SUNDAY FOR AMZ250-252-254-  
256.  
 

 
 

 
SYNOPSIS...DCH  
NEAR TERM...III  
SHORT TERM...MBB  
LONG TERM...MBB  
AVIATION...DL  
MARINE...  
 
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