227  
FXUS61 KAKQ 230833  
AFDAKQ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE WAKEFIELD VA  
433 AM EDT SUN APR 23 2017  
   
SYNOPSIS
 
 
A FRONTAL BOUNDARY BECOMES NEARLY STATIONARY ACROSS THE CAROLINAS  
TODAY. A STRONG LOW PRESSURE SYSTEM WILL CROSS THE REGION  
THROUGH MIDWEEK...AND BRING PERIODS OF MODERATE TO HEAVY  
RAINFALL TO THE REGION MONDAY AND TUESDAY.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
LATEST UPPER AIR ANALYSIS FEATURES A DEEPENING UPPER LEVEL LOW  
DIGGING FROM THE MID-MISSISSIPPI VALLEY INTO THE MID-SOUTH.  
THIS FEATURE WILL SLOWLY SLIDE E-SE INTO THE SOUTHEAST TODAY. AT  
THE SURFACE, QUASI-STATIONARY BOUNDARY EXTENDED FROM E SC BACK  
INTO THE DEEP SOUTH AT 07Z. THIS BOUNDARY WILL SLOWLY EDGE  
FARTHER SOUTH THROUGH THE DAY.  
 
REGIONAL RADAR MOSAIC SHOWING A WIDESPREAD LIGHT SHOWERS  
MOVING ACROSS THE AREA AT 08Z. THESE SHOWERS WILL CONTINUE TO  
PUSH E-SE ACROSS CENTRAL AND SOUTHERN VA INTO NC, AS A  
DAMPENING/WEAKENING UPPER SHORTWAVE DROPS ACROSS. EXPECT A BRIEF  
LULL IN AREAL COVERAGE OF SHOWERS AROUND SUNRISE THROUGH MID  
MORNING. AT THAT POINT, EXPECT SHOWERS TO REDEVELOP AS SURFACE  
LOW OVER E TN/N GA PUSHES ACROSS THE BOUNDARY TO THE SOUTH.  
RESULTANT DVPA/WEAK OVERRUNNING MOISTURE SHOULD PUSH IN OUR  
DIRECTION AND BRING ANOTHER ROUND OF SHOWERS TO THE CENTRAL AND  
SOUTHERN PORTIONS OF THE AREA FROM MID-MORNING INTO THE  
AFTERNOON, EVENTUALLY REACHING THE LOWER MD EASTERN SHORE THIS  
AFTERNOON INTO THE EVENING HOURS. POP SLOWLY INCREASES TO  
CATEGORICAL ALL ZONES BY THIS AFTERNOON. QPF TODAY 0.5-1" SW  
(I-85 CORRIDOR)...TO A QUARTER INCH OR LESS SOUTH OF I-64. LIGHT  
AMOUNTS FROM THERE NORTH THROUGH EARLY EVENING. HIGHS UPPER 50S  
TO LOW 60S COASTAL EAST...LOW TO MID 50S AS COOL AIR WEDGE SETS  
IN OVER THE PIEDMONT.  
 

 
   
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/
 
 
A CLOUDY AND WET PERIOD TO BEGIN THE WORK WEEK. PERIODS OF MDT  
TO HVY RAINFALL EXPECTED MONDAY NIGHT AND TUESDAY. QPF BTWN 1.5  
TO 3.5 INCHES (HIGHEST ACROSS THE SOUTHERN THIRD OF THE AREA).  
 
MODELS IN GENERAL AGREEMENT THAT AFOREMENTIONED UPR-LEVEL LOW  
CUTS OFF AS IT TRACKS SE ACROSS THE SOUTHEAST AND THE COASTAL  
CAROLINAS. SYSTEM THEN TAKES ON A NEG TILT MON NIGHT THAT  
SPAWNS A COASTAL LOW OFF THE SE COAST MONDAY. RESULTANT STRONG  
COASTAL FRONT WILL BE CONDUCIVE FOR HEAVY RAINFALL ACROSS THE  
SOUTHEAST CONUS, WHICH WILL EVENTUALLY MOVE IN OUR DIRECTION  
LATE MONDAY NIGHT AND TUESDAY.  
 
LOOK FOR MAINLY CLOUDY SKIES WITH PERIODS OF MDT TO LOCALLY HVY  
RAINFALL MON/TUE AS COPIOUS AMOUNTS OF DEEP ATLANTIC MOISTURE  
GETS ENTRAINED NORTH AND ROTATES AROUND THE SYSTEM. THUS,  
CONFIDENCE REMAINS HIGH ENOUGH TO GO WITH LIKELY TO CATEGORICAL  
POPS EACH PERIOD. KEPT HIGH POPS BUT LOW CHC THUNDER ALONG THE  
COAST.  
 
HIGHS MON IN THE MID 50S-MID 60S EXCEPT 65-70 SERN COASTAL  
AREAS. LOWS MON NITE IN THE UPR 40S-LWR 60S. HIGHS TUE IN THE  
LWR 60S-LWR 70S.  
 
HYDRO WISE, NO FLOOD HEADLINES ANTICIPATED ATTM WITH NUMEROUS BREAKS  
IN BETWEEN BOUTS OF RAIN EXPECTED. DO EXPECT SOME HEALTHY RISES IN  
LOCAL RIVER BY EARLY NEXT WEEK, ESPECIALLY IF THE HEAVY RAINFALL  
FALLS OVER THE HEADWATERS. GIVEN THE FORECASTED QPF AND AFTER COORD  
WITH THE RFC, EXPECT MINOR FLOODING AT LAWRENCEVILLE ON THE MEHERRIN  
RIVER BY TUE. AGAIN, THIS BASED ON QPF SO PLENTY OF TIME TO ADJUST  
IF NEEDED.  
 
RAIN TAPERS OFF FROM SOUTH TO NORTH TUESDAY NIGHT AS THE UPPER  
LOW PIVOTS OFFSHORE AND NE OF THE DELMARVA OVERNIGHT INTO  
WEDNESDAY MORNING. EARLY MORNING LOWS 55-60.  
 

 
   
LONG TERM /WEDNESDAY THROUGH SATURDAY/
 
 
LONG TERM PERIOD WILL FEATURE A TREND TOWARDS DRIER AND WARMER  
CONDITIONS. FOR TUE NIGHT, MID-LEVEL CUTOFF LOW AND ASSOCIATED  
SFC LOW START TO PROGRESS OFFSHORE, WITH SOME PCPN PSBL ON THE  
BACKSIDE OF THE SYSTM. POPS RANGE FROM 20-40%. WARMING TREND  
THEN COMMENCES FOR WED AS DEEP SWLY FLOW DEVELOPS ACROSS THE  
EASTERN SEABOARD, LASTING THROUGH THE END OF THE WEEK WITH TEMPS  
IN THE 70S WED REACHING THE 80S MOST AREAS THU AND FRI.  
 

 
   
AVIATION /09Z SUNDAY THROUGH THURSDAY/
 
 
AS OF 06Z...AN EAST TO WEST ORIENTED QUASI-STATIONARY FRONTAL  
BOUNDARY WAS ORIENTED TO THE SOUTH OF THE TERMINALS. NORTH OF  
THE FRONT, NORTH/NORTHEAST WINDS AND WIDESPREAD MVFR/IFR  
CEILINGS WERE PRESENT IN AND AROUND THE TAF SITES. THE FORECAST  
CALLS FOR SLOW IMPROVEMENT FOR NORTHERN PORTIONS OVERNIGHT INTO  
SUNDAY INCLUDING SBY/RIC WITH MVFR DETERIORATING TO IFR  
ELSEWHERE DURING THE AFTERNOON/EVENING SUNDAY 00Z TAF PERIOD.  
THE IFR WILL BE MAINLY DUE TO LOW CEILINGS BUT IFR VISIBILITY  
CAN BE EXPECTED DURING HEAVIER RAIN. CONFIDENCE IN DETAILS IS  
MODERATE WITH INDICATION THAT TEMPORARY IMPROVEMENT MAY OCCUR  
FROM TIME TO TIME. THIS WILL BE DIFFICULT TO PIN DOWN TIME AND  
LOCATION WISE.  
 
NORTHEAST WINDS WILL PREVAIL DURING THE PERIOD. THESE WINDS  
WILL OCCASIONALLY GUST TO AROUND 20 TO 25 KNOTS SOUTHEAST  
PORTIONS AT ORF AND ECG.  
 
OUTLOOK...A WELL ORGANIZED LOW PRESSURE SYSTEM WILL LINGER JUST OFF  
THE CAROLINA COAST FROM SUNDAY NIGHT INTO EARLY THIS COMING WEEK.  
UNSETTLED WEATHER CONTINUES INTO TUESDAY WITH WIDESPREAD  
RAINFALL FALLING HEAVILY AT TIMES W/DEGRADED AVIATION  
CONDITIONS. CURRENT FORECASTS HAVE THE LOW MOVING OFF TO THE  
NORTHEAST WEDNESDAY WITH A HIGH PRESSURE RIDGE BUILDING INTO THE  
SOUTHEAST STATES FROM THE ATLANTIC. WEDNESDAY THROUGH FRIDAY  
ARE EXPECTED TO BE DRY AND MAINLY VFR.  
 

 
   
MARINE
 
 
NORTHEAST FLOW PREVAILS OVER THE MARINE AREA, BETWEEN HIGH PRESSURE  
BUILDING INTO THE NORTHEAST AND LOW PRESSURE OVER THE SOUTHEAST.  
SPEEDS ARE GENERALLY 15-20 KNOTS, WITH MARGINAL SCA CONDITIONS IN  
THE BAY. WAVES GENERALLY 2-3 FEET AND SEAS 3-6 FEET (HIGHEST  
SOUTHERN COASTAL WATERS). HIGH PRESSURE BUILDS IN FROM THE NORTHWEST  
TODAY AS LOW PRESSURE REMAINS OVER THE SOUTHEAST. GRADIENT WINDS  
RELAX LATER THIS MORNING INTO THE AFTERNOON, RESULTING IN A BRIEF  
LULL IN SCA CONDITIONS. LONGER REPRIEVE EXPECTED IN THE UPPER BAY,  
SO HAVE OPTED TO DROP THE HEADLINES MID MORNING. IN THE SOUTHERN  
BAY, MARGINAL SCA CONDITIONS EXPECTED TODAY WITH OCCASIONAL GUSTS TO  
20-23 KNOTS. GUSTS OF 20-25 KNOTS ALSO EXPECTED IN THE SOUND AND  
SOUTHERN COASTAL WATERS TODAY. SEAS AVERAGE 4-6 FEET. HIGH PRESSURE  
SLIDES OFFSHORE TONIGHT AS LOW PRESSURE SLIDES TOWARD THE SOUTHEAST  
COAST. THE RESULT WILL BE AN UPTICK IN NORTHEAST WINDS TONIGHT, WITH  
SPEEDS OF 15-25 KNOTS. GUSTS UP TO 30 KNOTS IN THE COASTAL WATERS.  
SEAS INCREASE TO 5-8 FEET. AM CONCERNED GUIDANCE IS NOT HANDLING THE  
NORTHEAST FLOW AND LONG PERIOD SWELL THE BEST, SO HAVE OPTED TO GO  
ABOVE GUIDANCE ON WAVE HEIGHTS. THERE IS THE POTENTIAL FOR HIGH SURF  
CONDITIONS AS WELL, BUT THERE REMAINS SOME UNCERTAINTY SO HAVE HELD  
OFF ON HIGH SURF HEADLINES. SCA HEADLINES RETURN FOR THE RIVERS LATE  
TONIGHT. LOW PRESSURE SLIDES OFF THE SOUTHEAST COAST MONDAY AND  
DEEPENS. STRONGEST GRADIENT WINDS BEGIN TO EXPAND NORTHWARD MONDAY,  
WITH SPEEDS OF 15-25 KNOTS EXPECTED FROM THE MOUTH OF THE BAY  
NORTHWARD. A BRIEF LULL IS POSSIBLE FOR THE SOUND MONDAY. SEAS  
REMAIN 5-8 FEET, BUT SUBSIDE TO 4-6 FEET IN THE SOUTHERN COASTAL  
WATERS. WAVES 3-6 FEET (HIGHEST IN THE MOUTH OF THE BAY).  
 
LOW PRESSURE SLOWLY LIFTS ALONG THE SOUTHEAST COAST TUESDAY AND  
OFFSHORE THE MID-ATLANTIC COAST TUESDAY NIGHT. ONSHORE FLOW AND SCA  
CONDITIONS PERSIST. SEAS BUILD UPWARDS OF 6-9 FEET TUESDAY. FLOW  
BECOMES NORTHERLY TUESDAY NIGHT AS SPEEDS DIMINISH AT OR BELOW 15  
KNOTS AS THE LOW LIFTS OVER THE WATERS. SEAS SUBSIDE TO 4-6 FEET  
LATE TUESDAY NIGHT. WAVES 1-2 FEET. THE LOW WEAKENS AND LIFTS AWAY  
FROM THE REGION WEDNESDAY AS SUB-SCA CONDITIONS RETURN. SEAS  
FORECAST TO DROP BELOW 5 FEET LATE WEDNESDAY. THE NEXT FRONT  
APPROACHES THE WATERS FRIDAY.  
 

 
   
TIDES/COASTAL FLOODING
 
 
TIDAL DEPARTURES ARE AVERAGING 1 TO 1.5 FEET EARLY THIS MORNING  
THANKS TO PERSISTENT ONSHORE FLOW. TIDAL DEPARTURES WILL BUILD  
TODAY THROUGH MIDWEEK AS ONSHORE FLOW PREVAILS AHEAD OF AN  
APPROACHING AREA OF LOW PRESSURE. MAJORITY OF THE TIDAL  
LOCATIONS IN THE BAY AND ATLANTIC COAST WILL REACH ACTION STAGE  
TODAY AND TONIGHT, BUT NO MINOR FLOODING IS ANTICIPATED AT THIS  
TIME. HOWEVER, TIDAL DEPARTURES INCREASE TO 1.5 TO 2 FEET  
MONDAY. MINOR COASTAL FLOODING IS EXPECTED DURING HIGH TIDE  
MONDAY NIGHT AND AGAIN ON TUESDAY, ESPECIALLY IN THE LOWER  
CHESAPEAKE BAY AND ATLANTIC WATERS. DEPENDING ON THE EXACT TRACK  
OF THE LOW, HIGH END MINOR TO LOW END MODERATE COASTAL FLOODING  
IS POSSIBLE TUESDAY NIGHT. DEPARTURES SUBSIDE WEDNESDAY AS LOW  
PRESSURE LIFTS ALONG THE NORTHEAST COAST AND FLOW BECOMES  
OFFSHORE.  
 

 
   
AKQ WATCHES/WARNINGS/ADVISORIES
 
 
MD...NONE.  
NC...NONE.  
VA...NONE.  
MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT EDT  
MONDAY NIGHT FOR ANZ635>637.  
SMALL CRAFT ADVISORY UNTIL 6 AM EDT TUESDAY FOR ANZ632-634-650-  
652-654-656-658.  
SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ633.  
SMALL CRAFT ADVISORY UNTIL 10 AM EDT THIS MORNING FOR ANZ630-  
631.  
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EDT  
MONDAY NIGHT FOR ANZ638.  
 

 
 

 
SYNOPSIS...MAM  
NEAR TERM...MAM  
SHORT TERM...MPR/MAM  
LONG TERM...MAS  
AVIATION...MAM/LSA  
MARINE...SAM  
TIDES/COASTAL FLOODING...SAM  
 
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