943  
FXUS61 KAKQ 171947  
AFDAKQ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE WAKEFIELD VA  
347 PM EDT FRI AUG 17 2018  
   
SYNOPSIS
 
 
HIGH PRESSURE REMAIN OFF THE SOUTHEAST U.S. COAST THROUGH  
TONIGHT. A COLD FRONT MOVES SLOWLY INTO THE REGION OVER THE  
WEEKEND, BEFORE STALLING NEAR THE VIRGINIA AND NORTH CAROLINA  
BORDER EARLY NEXT WEEK.  
 

 
   
NEAR TERM /THROUGH SATURDAY/
 
 
AS OF 315 PM EDT FRIDAY...  
 
WIDESPREAD CUMULUS, A BIT MORE THAN YESTERDAY, AND A FEW  
SHOWERS/ISOLATED TSTMS HAVE DEVELOPED THIS AFTERNOON ACROSS  
PORTIONS OF THE AREA. COVERAGE SHOULD REMAIN SIMILAR TO WHAT IS  
BEING OBSERVED NOW, BUT DID BRING SLIGHT CHANCE POPS FURTHER  
EAST TO THE I-64/I-95 INTERCHANGE BASED ON RADAR TRENDS. CAM  
GUIDANCE HAS BEEN POOR IN REGARDS TO CONVECTIVE DEVELOPMENT, SO  
WILL HAVE TO KEEP A CLOSE EYE ON RADAR/VISIBLE TRENDS THROUGH  
EARLY EVENING FOR ANY NOTABLE CHANGES. OTHERWISE, EXPECT PARTLY  
CLOUDY SKIES INTO THE EVENING AND TEMPS FALLING INTO THE 80S.  
OVERNIGHT LOWS WILL BE IN THE LOW 70S WEST TO MID-UPPER 70S  
ALONG THE WATER.  
 
A FEW SHOWERS ARE POSSIBLE PRE-DAWN SATURDAY OVER THE EASTERN SHORE  
AS ADDITIONAL MOISTURE STREAMS IN FROM THE SOUTH OVER OPEN WATERS.  
THEN, A PRE-FRONTAL TROUGH APPROACHES MID-MORNING/EARLY AFTERNOON  
FROM THE WEST, LEADING TO SHOWER/TSTM DEVELOPMENT WEST-TO-  
EAST...WITH THE GREATEST COVERAGE EXPECTED AFTER NOONTIME,  
CONTINUING THROUGH EARLY SUNDAY MORNING. HIGH TEMPS SHOULD STILL  
REACH INTO THE LOW 90S AREAWIDE, EVEN WITH SKY COVER INCREASING FROM  
PARTLY TO MOSTLY CLOUDY.  
 

 
   
SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/
 
 
AS OF 315 PM EDT FRIDAY...  
 
FIRST WAVE OF MORE WIDESPREAD SHOWERS AND TSTMS WILL MOVE EAST  
OF THE AREA SATURDAY NIGHT. EXPECT AT LEAST SCATTERED SHOWERS TO  
LINGER ACROSS CENTRAL AND EASTERN SECTIONS OF THE AREA THROUGH  
SATURDAY NIGHT. WARM AND HUMID AGAIN, WITH LOWS IN THE LOW/MID  
70S.  
 
FRONTAL BOUNDARY SETTLES ACROSS THE AREA ON SUNDAY, WITH  
SCATTERED SHOWERS AND THUNDERSTORMS RE-DEVELOPING, ESPECIALLY  
DURING THE AFTERNOON/EVENING HOURS. AMOUNT OF CLOUDINESS ACROSS  
THE AREA WILL LIMIT MAX TEMPS. IN ADDITION, IF FLOW TURNS FROM  
THE NE SOON ENOUGH ACROSS THE LOWER MD EASTERN SHORE,  
TEMPERATURES COULD REMAIN IN THE UPPER 70S THERE. OTHERWISE,  
EXPECT MAX TEMPS TO BE A BIT COOLER ON SUNDAY, MAINLY IN THE  
MID/UPPER 80S.  
 
MONDAY LOOKS TO BE A COOLER DAY WITH HIGH TEMPS IN THE LOWER TO  
MID 80S, AS HIGH PRESSURE NOSES INTO NORTHERN PORTIONS OF THE  
AREA FROM THE NE. COULD WELL REMAIN IN THE UPPER 70S DELMARVA  
AREAS, SHOULD E/NE FLOW BE STRONG ENOUGH, AND SKIES REMAIN  
CLOUDY. OVERALL, MONDAY LOOKS TO BE A PARTLY TO MOSTLY CLOUDY  
DAY. SHOWERS AND TSTMS WILL AGAIN BE POSSIBLE, ESPECIALLY  
SOUTHERN THIRD OF THE REGION, WITH THE GREATEST COVERAGE DURING  
THE AFTERNOON HOURS. NAM APPEARS TOO PESSIMISTIC AT THIS TIME,  
AND HAVE GONE SOMEWHAT CLOSER TO GFS/ECMWF FOR POPS.  
 

 
   
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/
 
 
AS OF 330 PM EDT FRIDAY...  
 
AN UPPER LEVEL TROUGH WILL BE CENTERED OVER THE UPPER MIDWEST  
TUESDAY MORNING, WITH A BROAD UPPER RIDGE WELL OFFSHORE OF THE MID-  
ATLANTIC. THIS WILL PUT US IN MOIST SW FLOW ALOFT. AT THE SURFACE,  
LOW PRESSURE WILL BE CENTERED OVER ILLINOIS/MICHIGAN/WISCONSIN BY 12Z  
TUESDAY. AS THE AREA OF LOW PRESSURE MOVES EASTWARD ON TUESDAY, DEEP  
MOISTURE WILL SURGE INTO THE REGION AHEAD OF A TRAILING COLD FRONT  
(GFS FORECAST PW VALUES ARE BETWEEN 2-2.5" BY TUESDAY AFTERNOON).  
THUS, AM EXPECTING SCATTERED SHOWER/T-STORM DEVELOPMENT THROUGHOUT  
THE REGION DURING THE DAY ON TUESDAY, WITH COVERAGE PEAKING DURING  
THE AFTERNOON/EVENING HOURS. HAVE MAINTAINED CHANCE POPS THROUGHOUT  
THE CWA ON TUESDAY. THE LATEST 17/12Z GFS AND ECMWF ARE SLIGHTLY  
QUICKER WITH THE FROPA THAN YESTERDAY'S RUNS (CMC STILL A BIT  
SLOWER). THEREFORE, IT LOOKS LIKE THE BEST CHANCE FOR SHOWER/T-STORM  
DEVELOPMENT WED AFTERNOON-EVENING WILL BE ALONG AND AHEAD OF THE  
FRONT OVER SE VA/NE NC. HAVE POPS BETWEEN 20-50% (LOWEST NW/HIGHEST  
SE) ON WEDNESDAY. BOTH THE GFS AND ECMWF PUSH THE FRONT SOUTH OF THE  
CWA BY THURSDAY MORNING, BUT THE CMC STALLS IT OVER NE NC. WENT WITH  
A GFS/ECMWF SOLUTION FOR LATE NEXT WEEK, WITH MAINLY DRY (AND  
SLIGHTLY COOLER) WEATHER ON THURSDAY AND FRIDAY AS SFC HIGH PRESSURE  
REMAINS JUST NORTH OF THE REGION. CANNOT RULE OUT A STRAY SHOWER OR  
TWO ACROSS THE REGION (MOST LIKELY SOUTH OF I-64), BUT KEPT POPS AT  
OR BELOW 30% ON THU/FRI.  
 
AFTERNOON HIGH TEMPERATURES WILL BE IN THE MID TO UPPER 80S ON  
TUESDAY AND WEDNESDAY, WITH OVERNIGHT LOWS RANGING FROM AROUND 70  
DEGREES INLAND TO THE LOW-MID 70S IN COASTAL AREAS. SLIGHTLY COOLER  
(WITH LOWER DEW POINTS) BEHIND THE COLD FRONT ON THURSDAY AND  
FRIDAY, WITH HIGHS IN THE LOW-MID 80S.  
 

 
   
AVIATION /20Z FRIDAY THROUGH WEDNESDAY/
 
 
AS OF 150 PM EDT FRIDAY...  
 
BROAD REACH OF HIGH PRESSURE IS CENTERED OFF THE SOUTHEAST  
COAST AS OF 18Z. A SW WIND IS AVERAGING 10-12KT THIS AFTN WITH SCT  
CU BASES OF 4-6KFT. GUIDANCE CONTINUES TO BACK OFF ON THE  
POTENTIAL FOR LATE AFTN/EVENING SHOWERS/TSTMS WITH ONLY A 15-20%  
CHC FROM NEAR PHF SOUTH TO ECG AND <15% ELSEWHERE. PARTLY TO  
MOSTLY CLOUDY LATER TONIGHT WITH A SW WIND OF 5-8KT.  
 
A COLD FRONT WILL APPROACH FROM THE N SATURDAY WITH AN  
INCREASED CHC OF SHOWERS/TSTMS. THE FRONT WILL BE OVER THE  
REGION SUNDAY WITH THE CHC OF SHOWERS/TSTMS CONTINUING. THE  
FRONT DROPS S OF THE REGION MONDAY WITH A CHC OF SHOWERS/TSTMS  
MAINLY ACROSS SRN VA AND NE NC. UNSETTLED CONDITIONS POTENTIALLY  
CONTINUE INTO TUESDAY.  
 

 
   
MARINE
 
 
AS OF 330 PM EDT FRIDAY...  
 
NO HEADLINES NECESSARY WITH THIS FORECAST PACKAGE. SFC HIGH  
PRESSURE RESIDES OFFSHORE TONIGHT INTO SAT AS A TROUGH OF LOW  
PRESSURE REMAINS OVER THE MID ATLANTIC. SW WINDS UP TO ~15 KT  
OVER THE BAY AND 15-20 KT OVER COASTAL WTRS WITH 2-4 FT SEAS. A  
COLD FRONT THEN DROPS INTO THE AREA DURING THE DAY SUN LEADING  
TO UNSETTLED CONDITIONS WITH SW WINDS SHIFTING TO N/NE BY SUN  
NIGHT/MON. SUB-SCA CONDITIONS EXPECTED TO CONTINUE INTO EARLY  
NEXT WEEK.  
 

 
   
AKQ WATCHES/WARNINGS/ADVISORIES
 
 
MD...NONE.  
NC...NONE.  
VA...NONE.  
MARINE...NONE.  
 

 
 

 
SYNOPSIS...AJZ/BMS  
NEAR TERM...BMS  
SHORT TERM...AJZ/WRS  
LONG TERM...ERI  
AVIATION...BMS  
MARINE...MAS  
 
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