074  
FXUS61 KAKQ 141206  
AFDAKQ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE WAKEFIELD VA  
706 AM EST THU DEC 14 2017  
   
SYNOPSIS
 
 
A PAIR OF LOW PRESSURE SYSTEMS WILL PASS TO THE NORTH OF THE  
AREA THROUGH FRIDAY. WEAK LOW PRESSURE DEVELOPS OFF THE COAST  
FRIDAY, THEN TRACKS NORTHEAST WHILE STAYING OFFSHORE FRIDAY  
NIGHT. HIGH PRESSURE RETURNS SATURDAY.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
SFC LOW PRESSURE TRACKING EASTWARD ALONG THE MASON-DIXON LINE  
WILL PUSH OFFSHORE BETWEEN 12-15Z. THIS FEATURE WILL DRAG A  
WEAK COLD FRONT THROUGH THE AREA BY MIDDAY, PUSHING OFFSHORE  
THIS AFTERNOON. TEMPS ARE ALREADY OFF TO A MILDER START COMPARED  
TO YESTERDAY MORNING WITH READINGS CURRENTLY IN THE 30S TO  
AROUND 40. WE WILL CONTINUE TO BUILD ON THIS TREND THROUGH THE  
AFTERNOON WITH WNW FLOW PROMOTING DECENT MIXING. HIGH TEMPS WILL  
REACH THE UPR 40S N TO THE MID 50S OVER FAR SE VA & NE NC UNDER  
A MOSTLY SUNNY SKY. HIGH PRESSURE CENTERS ITSELF OVER MD  
TONIGHT WITH INCREASING MID/HIGH CLOUDS. COLDER ONCE AGAIN WITH  
LOWS FROM THE LOW 20S N-W TO THE LOW 30S SE COAST.  
 

 
   
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/
 
 
HIGH PRESSURE GETS SQUEEZED TO THE NE FRIDAY MORNING AS LOW  
PRESSURE AND AN UPPER TROUGH PIVOT THROUGH THE GREAT LAKES.  
MEANWHILE, A WEAK WAVE OF LOW PRESSURE IS EXPECTED TO DEVELOP  
OFF THE NC OBX AROUND MIDDAY FRIDAY, THEN QUICKLY TRACK NE WELL  
OFF THE MID-ATLANTIC COAST FRIDAY NIGHT. THINGS WILL HAVE TO  
COME TOGETHER JUST RIGHT FOR PHASING BETWEEN THE GREAT LAKES  
TROUGH AND THE COASTAL LOW TO PRODUCE POSSIBLE -RA/-SN SHOWERS  
OVER THE EASTERN SHORE/NORTHERN NECK FRIDAY AFTN/EARLY EVE.  
RIGHT NOW AM CARRYING SLIGHT CHC POPS (~20%) FOR THESE AREAS AS  
00Z ECMWF/RGEM AND TO A LESSER DEGREE THAN 00Z NAM ARE LENDING  
SOME CREDENCE TO THIS SCENARIO. OTHERWISE, FRIDAY WILL BE DRY  
WITH A PARTLY TO MOSTLY CLOUDY SKY. HIGHS FROM THE UPR 30S NW TO  
NEAR 50 SE COAST.  
 
DRY AND CHILLY FRIDAY NIGHT BEHIND THE DEPARTING SYSTEM. LOWS  
IN THE 20S EXCEPT LWR 30S SE COAST.  
 
HIGHS PRESSURE BUILDS ACROSS THE SE STATES SAT / SAT NITE,  
PROMOTING DRY WX. HIGHS IN THE MID-UPR 40S. LOWS SAT NIGHT IN  
THE MID 20S TO MID 30S.  
 

 
   
LONG TERM /SUNDAY THROUGH WEDNESDAY/
 
 
MODEL TIMING AND MOISTURE DIFFERENCES MAKE FOR A LOW CONFIDENCE  
FORECAST EARLY NEXT WEEK (DUE TO A SPLIT FLOW). THE ONE FACTOR THAT  
DOES SEEM TO BE IN AGREEMENT IS THAT TEMPS REMAIN WARM ENUF ACROSS  
THE LOCAL AREA FOR ANY PCPN TO FALL AS LIQUID.  
 
A WARM FRONT IS PROGGED TO LIFT NORTH OF THE AREA SUNDAY WITH SVRL  
SRN STREAM S/W'S PROGGED TO LIFT NE FROM THE DEEP SOUTH THRU TUE.  
SLGHT CHC POPS ACROSS THE PIEDMONT SUN AFTRN. HIGHS IN THE UPR 40S-  
MID 50S.  
 
ECMWF/CANADIAN HAVE WETTER SOLUTIONS BUT WITH TIMING DIFFERENCES  
WHILE THE GFS IS DRIER AND KEEPS THE DEEP MOISTURE SOUTH OF THE  
LOCAL AREA UNTIL LATE TUE. THUS, KEEPING SOME CONTINUITY WITH THE  
CURRENT FORECAST RESULTS IN KEEPING CHC POPS SUN NIGHT INTO TUE FOR  
NOW. (ALL LIQUID PCPN WITH NO HIGHER THAN 40 POP). DRY WED.  
 
LOWS SUN NITE IN THE UPR 30S NW TO MID 40S SE. HIGHS MON/TUE IN  
THE 50S. LOWS IN THE MID 30S NW TO LWR 40S SE. HIGHS WED IN THE  
UPR 40S-LWR 50S.  
 

 
   
AVIATION /12Z THURSDAY THROUGH MONDAY/
 
 
VFR CONDITIONS EXPECTED THROUGH THE 12Z/14 TAF FORECAST PERIOD.  
SW WINDS AOB 15 KT THIS MORNING BECOME NW THIS AFTERNOON AND  
NNE TONIGHT. VFR CONDITIONS CONTINUE INTO FRI AS HIGH PRESSURE  
DOMINATES. LOW PRESSURE OFF THE COAST MAY RESULT IN A FEW SNSHS  
AT SBY FRI EVE. HIGH PRESSURE RETURNS OVER THE WEEKEND.  
 

 
   
MARINE
 
 
STRONG SFC LOW PRESSURE MOVING OFF THE NJ COAST WITH PRESSURE  
FALLS ON THE ORDER OF 6MB/6HR CENTERED ACROSS THE NORTHERN  
COASTAL WATERS BUT SHIFTING OFF TO THE E. MAINTAINING THE SCA  
HEADLINES FOR WINDS MAINLY 20-25 KT WITH GUSTS TO 30 KT (A FEW  
GUSTS TO 35 KT HAVE BEEN OBSERVED FROM TIME TO TIME AT ELEVATED  
SENSORS BUT NOT ENOUGH TO WARRANT GALES).  
 
ONCE THE SYSTEM EXITS FARTHER OFFSHORE THIS AFTERNOON, HIGH  
PRESSURE WILL BEGIN TO PUSH ESE AND INTO THE LOCAL AREA FROM THE  
MIDWEST. THE HIGH WEAKENS A BIT WHILE DOING SO THIS AFTN AND  
EVENING AND THIS SHOULD ALLOW WNW WINDS TO DROP OFF LATER TODAY  
TO BELOW SCA THRESHOLDS BY LATER AFTN. ON FRIDAY, THE REGION  
WILL BE BETWEEN A FRONT TO THE SOUTH AND ANOTHER NORTHERN STREAM  
LOW PRESSURE SYSTEM. WINDS WILL BE GENERALLY LIGHT WITH SOME NE  
FLOW GRADUALLY TURNING TO THE SW AND THEN NW BY FRIDAY NIGHT.  
THERE DOES LOOK TO BE A REINFORCING SHOT OF COLDER AIR LATE FRI  
NIGHT INTO EARLY SAT AND THIS COULD LEAD TO MORE SCA CONDITIONS.  
HIGH PRESSURE RETURNS ON SUNDAY WITH THE FLOW TURNING BACK TO  
THE SW.  
 

 
   
TIDES/COASTAL FLOODING
 
 
A LOW WATER ADVISORY HAS BEEN ISSUED FOR THE LOWER BAY, JAMES &  
YORK RIVERS, AND PORTIONS OF THE COASTAL WATERS FOR THE MIDDAY  
LOW TIDE CYCLE. WATERS LEVELS WILL REACH -1.0 TO -1.5 FT MLLW.  
 

 
   
AKQ WATCHES/WARNINGS/ADVISORIES
 
 
MD...NONE.  
NC...NONE.  
VA...NONE.  
MARINE...LOW WATER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR ANZ632-  
634-636-638-652-654-656.  
SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR  
ANZ635>638-656-658.  
LOW WATER ADVISORY FROM NOON TODAY TO 6 PM EST THIS EVENING  
FOR ANZ637.  
SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR  
ANZ630>634-654.  
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ650-  
652.  
 

 
 

 
SYNOPSIS...JDM  
NEAR TERM...JDM  
SHORT TERM...JDM/MPR  
LONG TERM...MPR  
AVIATION...ALB/JDM  
MARINE...LKB  
TIDES/COASTAL FLOODING...  
 
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