734  
FXUS62 KILM 261200  
AFDILM  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE WILMINGTON NC  
800 AM EDT WED APR 26 2017  
   
SYNOPSIS
 
 
HIGH PRESSURE OFFSHORE WILL BRING A WARMING AND DRYING TREND  
INTO THE WEEKEND. A WEAKENING AND LINGERING COLD FRONT WILL  
BRING A CHANCE OF SHOWERS OR A THUNDERSTORM LATE THURSDAY AND  
FRIDAY, WITH TEMPERATURES REMAINING WARM. A STRONGER FRONTAL  
SYSTEM WILL BRING A CHANCE OF RAIN EARLY NEXT WEEK. INLAND  
AREAS MAY SEE TEMPERATURES OF 90 DEGREES OR HIGHER FRIDAY  
AND SATURDAY AFTERNOON.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
AS OF 8 AM WEDNESDAY...STRANDS OF MIST AND FOG INLAND WILL BURN  
OFF FULLY BY 930 AM. MID-LEVEL DRYING WILL PRESS DOWN TO 6-7  
THOUSAND FEET TODAY, AND COMBINED WITH WESTERLY FLOW AT THIS  
LEVEL AND LATE APRIL SUNSHINE, A BREAKING UP OF MORNING CLOUDS  
IS EXPECTED. AFTERNOON HEATING AND LINGERING LOW-LEVEL MOISTURE  
THIS AFTERNOON WILL BRING DIURNAL CUMULUS OF LIMITED VERTICAL  
EXTENT, SUCH THAT PRECIPITATION IS NOT EXPECTED. THE SNAP BACK  
SHORT-WAVE RIDGE WILL HELP BOOST AFTERNOON TEMPERATURES FROM THE  
MIDDLE 80S WELL INLAND TO THE LOW 80S ALONG THE COASTAL  
INTERIOR AND UPPER 70S CLOSER TO THE COAST. INCREASING LOW LEVEL  
WINDS TONIGHT INTO EARLY THURSDAY WILL LIKELY PREVENT FOG AND  
MIST FROM DEVELOPING, AND RELATIVE HUMIDITY VALUES OVERNIGHT DO  
NOT APPEAR TO SUPPORT MUCH STRATUS EARLY THURSDAY.  
 

 
   
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/
 
 
AS OF 330 AM WEDNESDAY...LOW AMPLITUDE RIDGING ALOFT TO AFFECT  
THE FA THU, COMPLEMENTS TO THE NORTHEAST MOVING UPPER CLOSED  
LOW. THE ASSOCIATED RIDGE AXIS, OVERHEAD AT THE START OF THIS  
PERIOD, WILL SLIDE EAST AND OFF THE CAROLINA COASTS BY THU  
EVENING. AN EXPANSIVE AND RATHER AMPLIFIED UPPER TROF WILL  
BECOME ESTABLISHED ACROSS MUCH OF THE CONUS WITH IT'S TROF AXIS  
NEARLY MIMICKING THE CONTINENTAL DIVIDE. AT THE SFC, WEAK HIGH  
PRESSURE CENTERED WELL OFFSHORE FROM FLORIDA, WILL RIDGE BACK  
ACROSS THE SOUTHERN PORTIONS OF THE FA THU. AN EASTWARD MOVING  
AND WEAK FRONTAL BOUNDARY, WELL DISPLACED FROM IT'S PARENT SFC  
LOW NEAR HUDSON BAY, WILL APPROACH FROM THE WEST BEFORE  
STALLING ACROSS THE FAR WESTERN CAROLINAS AND VIRGINIA FRIDAY  
MORNING. MOISTURE ACCOMPANYING THE FRONT REMAINS LIMITED, AND  
WILL EVENTUALLY PUSH WELL AHEAD OF THE STALLED FRONT BY FRIDAY  
MORNING. JUST ENOUGH DYNAMICS AND WEAK INSTABILITY TO AID  
ISOLATED TO WIDELY SCATTERED SHOWERS LATE THU NIGHT THRU MIDDAY  
FRIDAY ALONG WITH A POSSIBLE RUMBLE OF THUNDER.  
 
UPPER LEVEL RIDGING WILL SPRING BACK UP ACROSS THE SOUTHEAST  
STATES AND THE ATLANTIC WATERS. 5H HEIGHTS RISE TO 590+ DAM.  
STRENGTHENING BERMUDA HIGH PRESSURE WILL RIDGE BACK TO THE WEST  
AND EXTEND INLAND IN THE VICINITY OF CAPE ROMAIN BY DAYBREAK  
SAT. SUBSIDENCE ALOFT, IE. NVA, WILL BECOME MORE DOMINANT LATE  
FRI AFTN AND NIGHT, ESSENTIALLY PUTTING A LID ON ANY CONVECTION  
THAT TRIES TO DEVELOP.  
 
THE PRE-DAWN HOURS OF THU, AND FRI AND SAT WILL EACH FEATURE A  
SW LOW LEVEL JET. THE STRONGER JETS WILL OCCUR FRI AND SAT  
MORNINGS. THIS WILL AID IN KEEPING SW WINDS ACTIVE AT THE SFC  
AND IN TURN LIKELY PREVENTING ANY RADIATIONAL FOG DEVELOPMENT  
EACH NIGHT.  
 
AS FOR DAILY MAX AND MIN TEMPS FOR THE 2 DAYS, YOU MAY BE  
LOOKING AT THE WARMEST TEMPS OF THE SPRING SEASON SO FAR. MODEL  
MOS GUIDANCE SHOWS WIDESPREAD 80S BOTH DAYS WITH 90 DEGREE  
READINGS POSSIBLE INLAND LOCATIONS ON FRI. IN ESSENCE, WILL BE  
LOOKING AT MAX/MIN TEMPS RUNNING UP TO 15 DEGREES ABOVE CLIMO.  
 

 
   
LONG TERM /SATURDAY THROUGH TUESDAY/
 
 
AS OF 300 PM TUESDAY...SURFACE AND MID LEVEL RIDGING WILL BE  
THE DOMINANT FEATURES THROUGH THE WEEKEND. THE 5H RIDGE AXIS IS  
JUST OFFSHORE AND A SLOW BUT STEADY INCREASE IN MOISTURE AS FLOW  
ALOFT BECOMES MORE SOUTHWESTERLY OPENS UP THE POSSIBILITY OF  
SEA BREEZE/DIURNAL CONVECTION, ESPECIALLY SUN AFTERNOON AND  
EVENING. TEMPERATURES WILL BE ABOVE TO WELL ABOVE CLIMO WITH  
POTENTIAL FOR 90 DEGREE READINGS INLAND.  
 
NEXT SYSTEM WINDS UP OVER THE CENTRAL CONUS EARLY NEXT WEEK, LIFTING  
FROM THE PLAINS ON SUN TO THE GREAT LAKES ON MON. WARM ADVECTION  
AHEAD OF THE FRONT WILL MAINTAIN TEMPS ABOVE CLIMO THROUGH MON. COLD  
FRONT TRAILING THE LOW MOVES INTO THE AREA LATER MON PRECEDED BY  
CONVECTION. BEST DYNAMICS PASS WELL NORTH OF THE AREA BUT THERE WILL  
BE A NARROW BAND OF DEEPER MOISTURE ALONG WITH LOW LEVEL CONVERGENCE  
AND A STRENGTHENING LOW LEVEL JET. ALSO POTENTIAL FOR SOME PVA  
DEPENDING ON TIMING OF ANY SHORTWAVE ROTATING AROUND THE BASE OF THE  
TROUGH. SURFACE HIGH AND BROAD TROUGHING ALOFT TUE CONTRIBUTE TO  
DEEP WESTERLY FLOW, DRYING THE REGION OUT BUT WITH A COOLER AIR MASS  
BUILDING IN TEMPS WILL BE SLIGHTLY BELOW CLIMO AS THE PERIOD  
ENDS.  
 

 
   
AVIATION /12Z WEDNESDAY THROUGH SUNDAY/
 
 
AS OF 12Z...MVFR AND POCKETS OF IFR WILL OCCUR ACROSS THE REGION  
THRU 14Z, EITHER FROM CEILINGS 1K-2K FEET AND/OR BR/FG  
ESPECIALLY AREAS OUTSIDE THE VEIL OF SC/AC CLOUDINESS. AS THE  
STACKED LOW MOVES FURTHER AWAY TODAY, TEMPORARY UPPER LEVEL  
RIDGING AND SFC RIDGING FROM OFF THE SE ATLANTIC WILL BOTH  
AFFECT THE FA BY THIS AFTN THRU TONIGHT, ENDING THE CYCLONIC  
FLOW ASSOCIATED WITH THE RETREATING STACKED LOW OFF TO THE  
NORTHEAST. LIGHT NW-W FLOW THIS MORNING WILL BACK TO THE SW THIS  
AFTN THRU TONIGHT. COASTAL TERMINALS MAY SEE IT BACK TO THE S  
DUE TO A THE DEVELOPMENT OF AN AFTN/EVENING WEAK SEA BREEZE.  
A LOW LEVEL SW 20 TO 30 KT JET WILL DEVELOP AND AFFECT THE  
AREA TERMINALS BETWEEN 04Z THRU 12Z THU. THIS WILL KEEP WINDS  
ACTIVE AT THE SFC AND LIKELY PREVENT ANY WIDESPREAD FOG. IF THIS  
JET IS WEAKER THAN EXPECTED OR DOES NOT QUITE DEVELOP AS  
EXPECTED, FOG WOULD THEN BECOME AN ISSUE ESPECIALLY WITH GROUNDS  
STILL REMAINING NEARLY SATURATED FROM THE HEAVY RAINFALL EVENT  
OF THE PAST 2 DAYS.  
 
EXTENDED OUTLOOK...VFR EXPECTED FROM THURSDAY AFTERNOON THROUGH  
SUNDAY. ISOLATED MVFR FROM SPOTTY SHOWERS THU NIGHT.  
 

 
   
MARINE
 
 
NEAR TERM /THROUGH TONIGHT/...  
AS OF 8 AM WEDNESDAY...LIGHT WINDS MUCH OF THE DAY WILL ALLOW  
SE SWELL TO REMAIN THE DOMINANT WAVE ENERGY ALTHOUGH ITS  
INTENSITY WILL WANE TODAY. BY LATE DAY AND OVERNIGHT, INCREASING  
SW WINDS WILL BRING MODERATE CHOPPINESS TO THE WATERS WITH 4-5  
SECOND WAVE PERIODS BECOMING MORE DOMINANT. NO SHOWERS OR TSTMS  
HOWEVER ARE EXPECTED THROUGH THE OVERNIGHT PERIOD, BUT EXPECT  
GUSTS TO 20 KT FROM THE INSHORE SEA BREEZE THIS AFTERNOON, AND  
THEN THROUGHOUT THE COASTAL WATERS TONIGHT AS THE PRESSURE  
GRADIENT TIGHTENS.  
 
AS OF 330 AM WEDNESDAY...THE SYSTEM MOVING INTO THE NORTHEAST  
WILL NO LONGER BE THE MAIN WIND-MAKING FEATURE TODAY. IN ITS  
WAKE THE HIGH OVER THE ATLANTIC WILL BRING A S TO SW FLOW. AN  
APPROACHING COLD FRONT WILL ALSO SLIGHTLY CONTRIBUTE. WITH THE  
COAST BETWEEN THE TWO WINDS WILL BE QUITE LIGHT. SEAS WILL  
SETTING INTO A GENERAL 2 TO 3 OR 4 FT RANGE. SOME LARGER WAVES  
OUTSIDE OF 20NM HAVE SWELL ENERGY FROM THE DEPARTING STORM AS  
EVIDENCED BY THE 10 SEC DOMINANT PERIOD.  
 
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...  
AS OF 330 AM WEDNESDAY...THURSDAY WILL FEATURE WEAK RIDGING FROM  
OFFSHORE HIGH PRESSURE EAST OF FLORIDA, EXTENDING INLAND JUST  
SOUTH OF THE AREA WATERS. THURSDAY WILL SEE SSW TO SW FLOW AT  
10 TO 15 KT WITH AN 8 TO 9 SECOND PERIOD ESE GROUND SWELL  
DOMINATING THE SIGNIFICANT SEAS. BY LATE FRIDAY THRU FRIDAY  
NIGHT, STRENGTHENING RIDGING SFC AND ALOFT, WILL AFFECT THE AREA  
WATERS. THE SFC PG WILL TIGHTEN-SOME, RESULTING WITH SW 10 TO 20  
KT WINDS. AN ESE GROUND SWELL WILL REMAIN PRESENT BUT INCREASING  
SHORT PERIOD WIND WAVES WILL EVENTUALLY DOMINATE THE SIGNIFICANT  
SEAS. IN ADDITION, A SW LOW LEVEL JET WILL AFFECT THE LOCAL  
WATERS DURING THE PRE-DAWN HRS OF THU, FRI AND SAT. THE  
STRONGEST LOW LEVEL JET WILL OCCUR FRI MORNING AND MAY JUST BE  
STRONG ENOUGH TO PRODUCE SCEC AND/OR SCA CONDITIONS. WILL  
MONITOR. THE AFTN/EVENING SEA BREEZE EACH DAY WILL ALSO PROVIDE  
ADDITIONAL CHOPPINESS TO THE OVERALL SEAS.  
 
LONG TERM /SATURDAY THROUGH SUNDAY/...  
AS OF 300 PM TUESDAY...HIGH PRESSURE WILL BE THE DOMINANT  
FEATURE THROUGH THE PERIOD WITH SOUTH TO SOUTHWEST FLOW IN  
PLACE. SPEEDS WILL BE ON THE LOW END OF THE 10 TO 15 KT RANGE  
EARLY IN THE PERIOD BUT INCREASE TO A SOLID 15 KT SUN AS  
GRADIENT BECOMES A LITTLE MORE DEFINED. SEAS MOSTLY 2 TO 3 FT  
EARLY IN THE PERIOD WILL EXPERIENCE AN UPWARD TREND LATE IN  
RESPONSE TO INCREASING SOUTHWEST FLOW.  
 

 
   
ILM WATCHES/WARNINGS/ADVISORIES
 
 
SC...NONE.  
NC...NONE.  
MARINE...NONE.  
 

 
 

 
 
SYNOPSIS...8  
NEAR TERM...8  
SHORT TERM...DCH  
LONG TERM...III  
AVIATION...DCH  
MARINE...MBB/DCH/MBB  
 
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