011  
FXUS61 KAKQ 230534  
AFDAKQ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE WAKEFIELD VA  
134 AM EDT THU MAR 23 2017  
   
SYNOPSIS
 
 
CANADIAN HIGH PRESSURE BUILDS INTO THE MID ATLANTIC STATES  
THROUGH THURSDAY. A GRADUAL WARMING TREND BEGINS FRIDAY INTO  
THE UPCOMING WEEKEND. A MORE ACTIVE WEATHER PATTERN IS  
ANTICIPATED SUNDAY NIGHT INTO THE FIRST HALF OF NEXT WEEK.  
 

 
   
NEAR TERM /UNTIL 6 AM THIS MORNING/
 
 
WINDS CONTINUE TO DIMINISH LATE THIS EVENING UNDER A CLEAR SKY.  
EXPECTING WINDS TO BECOME CALM AWAY FROM THE WATER OVERNIGHT  
WHICH WILL SET THE STAGE FOR CHILLY READINGS. STILL  
ANTICIPATING LOWS OF 22-25F NORTH OF INTERSTATE 64 (INCLUDING  
INTERIOR MD LOWER EASTERN SHORE), 26-28F INLAND VA/NE NC, AND  
29-33 FAR SE VA/NE NC COASTAL AREAS.  
 

 
   
SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/
 
 
CANADIAN HIGH PRESSURE CONTINUES TO SETTLE OVER THE MID ATLANTIC  
REGION ON THU AND THEN SLOWLY SLIDES OFFSHORE THU NIGHT.  
SLIGHTLY COOLER WITH CONTINUED DRY CONDITIONS THU/THU NIGHT.  
HIGHS IN THE UPPER 40S TO AROUND 50F INLAND/LOW-MID 40S  
IMMEDIATE COAST AND MD/VA EASTERN SHORE. LOWS IN THE UPPER 20S  
TO 32F INLAND /LOW-MID 30S BEACHES.  
 
DRY WITH A GRADUAL WARMING TREND FRI THROUGH SAT AS HIGH  
PRESSURE SHIFTS WELL OFFSHORE, AND A WARM FRONT LIFTS NORTHWEST  
OF THE AREA... ALLOWING WARM AIR ADVECTION TO COMMENCE WITH  
WINDS BECOMING MORE S-SW. TEMPERATURES ARE EXPECTED TO REBOUND  
TO 60-65F MOST INLAND AREAS (MID 50S TO LOWER 60S BEACHES AND  
MD/VA EASTERN SHORE) DUE TO BREEZY SOUTHWEST WINDS GUSTING TO  
AROUND 20 MPH INLAND AND UP TO 25 MPH MD/VA EASTERN SHORE.  
OVERALL CONDITIONS WILL BE DRY AS MID-UPPER LEVEL RIDGING AND  
DECENT SUBSIDENCE ALOFT DOMINATES (I.E. BEST SHOWER CHANCES ARE  
WELL NORTH ALONG THE WARM FRONT). OTHERWISE, MID-HIGH CLOUDS  
SHOULD STREAM ACROSS THE REGION (ESPECIALLY NORTH) IN RELATIVELY  
FLAT, UPPER LEVEL FLOW THROUGH FRI NIGHT. LOWS AROUND 50F.  
 
MEANWHILE, LOW PRESSURE EXITS THE INTERMOUNTAIN WEST INTO THE  
CENTRAL PLAINS FRI INTO FRI NIGHT. AS THE LOW TRACKS INTO THE  
WRN MIDWEST ON SAT, A SECONDARY WARM FRONT IS EXPECTED TO LIFT  
THROUGH THE AREA. THIS WILL ALLOW FOR ADDITIONAL WARMING IN  
CONTINUED SOUTHWEST SFC WINDS AND A NOTICEABLE INFLUX OF  
MOISTURE AS DEWPOINTS INCREASE TO AROUND 50F. ALTHOUGH CLOUDS  
SHOULD CLEAR OUT ACROSS THE SE HALF OF THE AREA DURING THE DAY  
(AS IS TYPICAL WITH A WARM FRONTAL PASSAGE), AFTN CUMULUS  
DEVELOPMENT AND INCREASING CIRRUS FROM THE WEST WILL KEEP PARTLY  
SUNNY WORDING IN THE FORECAST. TAKING ALL OF THE ABOVE INTO  
ACCOUNT AS WELL AS IMPROVED DAYTIME HEATING WITH AN INCREASING  
SUN ANGLE, WENT WITH A BLEND OF WPC/MOSGUIDE FOR HIGHS ON SAT  
AND BUMPED UP THE EASTERN SHORE DUE TO THE SOUTHWEST WINDS  
PRESENT. EXPECT HIGHS IN THE MID 70S INLAND/LOW- MID 70S BEACHES).  
 

 
   
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/
 
 
MEDIUM RANGE OF THE FORECAST PERIOD CHARACTERIZED BY NEAR TO  
ABOVE NORMAL TEMPERATURES, COURTESY OF ARRIVING MID-LEVEL  
RIDGING ALOFT, AND SURFACE HIGH PRESSURE ORIENTED JUST OFF THE  
MID ATLANTIC/SOUTHEAST COAST. MAIN WEATHER FEATURES OF NOTE WILL  
BE A SERIES OF MID/UPPER LEVEL TROUGHS...BRINGING A FEW PERIODS  
OF SCATTERED LIGHT PRECIPITATION OVER THE WEEKEND/EARLY NEXT  
WEEK. THE FIRST OF THESE DISTURBANCES TRAVERSES ACROSS THE  
CENTRAL/SOUTHERN PLAINS ON SATURDAY, DAMPENING AS IT CROSSES  
E-NE INTO THE OHIO VALLEY AND GREAT LAKES ON SUNDAY AND INTO THE  
NORTHEAST ON MONDAY. THIS FEATURE WILL ALLOW FOR SOME ISOLATED  
TO SCATTERED SHOWERS SUNDAY AFTERNOON INTO EARLY ON MONDAY. QPF  
WILL BE LIMITED WITH THIS FEATURE. INSTABILITY AND WEAKENING  
DYNAMICS/FORCING REMAIN MAXIMIZED WELL OFF TO OUR N-NW, AND WILL  
THEREFORE MAINTAIN 40-60% POP OVER OUR WESTERN/NW TIER FOR SOME  
SCT TO NUMEROUS SHOWERS SUNDAY EVENING INTO MONDAY MORNING, WITH  
LESSER POPS FOR MORE ISOLATED SHOWERS ACROSS THE SE COASTAL  
PLAIN. MILD SOUTHERLY FLOW WILL KEEP TEMPS MILD, WITH FORECAST  
HIGHS IN THE UPPER 50S TO 60S NORTHERN NECK AND LOWER MD EASTERN  
SHORE...WITH UPPER 60S TO LOW 70S INLAND FOR THE WEEKEND INTO  
EARLY NEXT WEEK.  
 
FOR THE MIDDLE OF NEXT WEEK...ATTENTION TURNS TO A PAIR OF  
SHORTWAVES. A SECOND SOUTHERN STREAM DISTURBANCE IS EXPECTED TO  
TRACK EAST/NORTHEASTWARD FROM THE CA COAST...ACROSS THE PLAINS  
AND MID-SOUTH LATE SAT TO EARLY MONDAY. THIS SYSTEM WILL  
CONTINUE TO WEAKEN AS IT PUSHES ACROSS THE EASTERN THIRD OF THE  
CONUS MONDAY THROUGH EARLY TUESDAY. MEANWHILE, A NORTHERN STREAM  
SYSTEM WILL DROP FROM THE PAC NW TOWARD THE NORTHERN PLAINS  
EARLY MONDAY, EVENTUALLY REACHING THE GREAT LAKES BY THE MIDDLE  
OF NEXT WEEK. MODELS ARE STILL SPLIT ON THE EVOLUTION OF THESE  
SYSTEMS. THE 12Z/22 ECMWF AND 00Z EC ENSEMBLES REMAINS QUICKER  
TO DAMPEN THESE FEATURES WITH THE GFS/GEFS A BIT STRONGER/MORE  
AMPLIFIED. TAKING A MIDDLE OF THE ROAD APPROACH REMAINS THE  
PREFERENCE AT THIS POINT, WITH THE RESULTANT BLENDED SOLUTION  
ALLOWING FOR CONTINUED MILD WEATHER MON TO WED WITH AT LEAST A  
SMALL CHANCE FOR SHOWERS ON TUESDAY AND TUESDAY NIGHT. SHORTWAVE  
RIDGING REBUILDS BEHIND THIS SYSTEM FOR WEDNESDAY. HIGHS REMAIN  
MILD THROUGH THE PERIOD, WITH 50S AND 60S OVER THE NORTHERN  
NECK OF VA INTO MD, WITH HIGHS WELL INTO THE 60S TO MID 70S  
INLAND. EARLY MORNING LOWS MAINLY IN THE 40S TO LOW 50S SOUTHERN  
SECTIONS.  
 

 
   
AVIATION /06Z THURSDAY THROUGH MONDAY/
 
 
HIGH PRESSURE/FAIR WEATHER PREVAILS OVER THE REGION THIS  
MORNING. A FEW HIGH CLOUDS AT OR ABOVE 25K FEET AGL ARE  
STREAMING OVER THE REGION, WITH LITTLE AVIATION IMPACT. SURFACE  
WINDS GENERALLY NORTH TO NORTHEAST AT OR BELOW 10 KNOTS. SKC  
CONDITIONS EXPECTED TODAY AS HIGH PRESSURE SETTLES OVER THE  
REGION. WINDS BECOME SOUTH TO SOUTHEAST THIS AFTERNOON,  
REMAINING AT OR BELOW 10 KNOTS.  
 
OUTLOOK...HIGH PRESSURE/FAIR WEATHER PREVAILS THROUGH SATURDAY.  
A STORM SYSTEM APPROACHES FROM THE WEST ON SUNDAY, WITH A GOOD  
CHANCE OF SHOWERS LATE SUNDAY THROUGH MONDAY.  
 

 
   
MARINE
 
 
7 PM UPDATE...  
ALL GALE WARNINGS WERE ALLOWED TO EXPIRE AT 7 PM. SCA EXPIRED IN  
THE EASTERN VIRGINIA RIVERS EXCEPT THE LOWER JAMES. OTHERWISE  
SCA WILL BE IN EFFECT THROUGH EARLY THURSDAY MORNING EXCEPT  
CONTINUING IN THE COASTAL WATERS SOUTH OF CAPE CHARLES DUE TO  
SEAS THROUGH MIDDAY.  
 
PREVIOUS DISCUSSION...  
LATEST OBS REFLECT STRONG SURGE OF NORTHERLY WINDS ONGOING  
ACROSS THE WATERS THIS AFTERNOON. WINDS AVERAGING NORTH AT  
25-30 KT WITH GUSTS TO 30-35 KT OVER THE BAY AND COASTAL WATERS  
INTO THE MOUTH OF THE JAMES RIVER.  
 
WILL BE ALLOWING GALE HEADLINE TO EXPIRE OVER THE CHES BAY NORTH  
OF LITTLE CREEK, STEPPING BACK TO SCA THROUGH TONIGHT. WILL  
MAINTAIN A GALE FOR THE MOUTH OF CHESAPEAKE BAY AND THE COASTAL  
WATERS THROUGH 23Z (7PM EDT) FOR WINDS GENERALLY 25-30 KT WITH  
GUSTS TO AROUND 35-40 KT. LAPS/MSAS SHOWING STRONG 3-HR PRESSURE  
RISES ON THE ORDER OF 2-4 MB OVER THE WATERS WITH DECENT FLOW  
ALOFT MIXING DOWN 30-35 KT WIND GUSTS OVER THE WATERS THIS  
AFTERNOON. LOW PRESSURE SLIDES FARTHER OFF THE COASTAL CAROLINAS  
THROUGH TONIGHT AS STRONG ~1040MB CANADIAN HIGH PRESSURE BUILDS  
FROM THE GREAT LAKES INTO THE OHIO VALLEY. PRESSURE GRADIENT  
WILL SLACKEN AS THE HIGH BUILDS OVERHEAD OVERNIGHT. SCA OVER THE  
RIVERS DROP THIS EVENING, AND OVER THE BAY EARLY THU MORNING.  
EXISTING GALES OVER THE COASTAL WATERS AND MOUTH OF THE BAY AND  
THE CURRITUCK SOUND SHOULD BE ABLE TO BE DROPPED ON TIME EARLY  
THIS EVENING, WITH A PERIOD OF SCA NEEDED THROUGH THE NIGHT  
BEFORE DROPPING BELOW SCA THRESHOLDS THU MORNING/EARLY AFTN OVER  
SOUTHERN WATERS. SEAS OF AROUND 5-8 FT ATTM (HIGHEST SOUTHERN  
COASTAL WATERS) SLOWLY SUBSIDE TONIGHT WITH WAVES OF 4-5 FEET.  
 
HIGH PRESSURE SETTLES OVER THE WATERS THURSDAY MORNING WITH  
WINDS BECOMING NORTH TO NORTHEAST AT OR BELOW 15 KNOTS. SEAS  
GRADUALLY SUBSIDE FROM NORTH TO SOUTH THURSDAY MORNING, FINALLY  
DROPPING BELOW 5 FT THRESHOLD IN THE SOUTHERN COASTAL WATERS BY  
EARLY THURSDAY AFTERNOON.  
 
HIGH PRESSURE SLIDES OFFSHORE THURSDAY NIGHT WITH FLOW BECOMING  
SOUTHWEST FRIDAY AND LINGERING THROUGH SATURDAY. SPEEDS INCREASE  
TO 15-20 KNOTS FRIDAY AFTERNOON AS A STORM SYSTEM DEVELOPS OVER  
THE MIDWEST. THE NEXT FRONT CROSSES THE WATERS EARLY NEXT WEEK,  
WITH RELATIVELY BENIGN MARINE CONDITIONS EXPECTED OVER THE  
WEEKEND IN LIGHT RETURN FLOW, COURTESY OF HIGH PRESSURE ANCHORED  
OVER THE WESTERN ATLANTIC. SEAS REMAIN 2-3 FT, WAVES 1-2 FT.  
 

 
   
EQUIPMENT
 
 
RADAR KDOX REMAINS INOPERABLE DUE TO A BAD SPECTRUM FILTER.  
MAINTENANCE IS EXPECTED TO BEGIN OVERNIGHT WITH AN ESTIMATED  
(THOUGH POSSIBLY UNSTABLE) RETURN TO SERVICE IS NOW FRIDAY,  
MARCH 24TH.  
 

 
   
AKQ WATCHES/WARNINGS/ADVISORIES
 
 
MD...NONE.  
NC...NONE.  
VA...NONE.  
MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EDT THIS MORNING FOR  
ANZ630>634-650-652-654.  
SMALL CRAFT ADVISORY UNTIL 4 AM EDT EARLY THIS MORNING FOR  
ANZ638.  
SMALL CRAFT ADVISORY UNTIL 1 PM EDT THIS AFTERNOON FOR ANZ656-  
658.  
 

 
 

 
SYNOPSIS...BMD  
NEAR TERM...BMD/JDM  
SHORT TERM...BMD  
LONG TERM...MAM  
AVIATION...SAM/LSA  
MARINE...MAM/LSA  
EQUIPMENT...  
 
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