286  
FXUS61 KAKQ 192050  
AFDAKQ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE WAKEFIELD VA  
450 PM EDT FRI APR 19 2019  
   
SYNOPSIS
 
 
A STRONG COLD FRONT WILL CROSS THE AREA THIS EVENING INTO EARLY  
SATURDAY. AN UPPER LEVEL LOW WILL BE SLOW TO LIFT AWAY TO THE  
NORTHEAST OVER THE WEEKEND.  
 

 
   
NEAR TERM /UNTIL 6 AM SATURDAY MORNING/
 
 
AS OF 425 PM EDT FRIDAY...  
 
SIGNIFICANT WX EXPECTED ACRS THE CWA FM LATE THIS AFTN INTO  
EARLY SAT MORNING, AS NUMEROUS SHOWERS/TSTMS RIGHT IN ADVANCE OF  
A COLD FRONT AND WELL AHEAD OF A DIGGING UPPER TROUGH TO THE  
WEST, WILL PUSH ENE ACRS THE REGION. A POTENTIALLY VOLATILE  
COMBINATION OF WIND SHEAR AND INSTABILITY, ALONG WITH PWATS  
BETWEEN 1.5-1.7 INCHES, WILL RESULT IN THE POSSIBILITY OF STRONG  
OR SEVERE STORMS, ALONG WITH CONCERN FOR HEAVY RAIN/FLASH  
FLOODING.  
 
THE MAIN THREAT WITH ANY SEVERE STORMS WILL BE FOR DAMAGING WIND  
GUSTS, ESPECIALLY IN ANY BOWING LINE SEGMENTS THAT FORM. HOWEVER,  
MODEL FORECAST SOUNDINGS CONTINUE TO INDICATE 100 TO AS MUCH AS  
300 M2/S2 OF 0-1KM STORM RELATIVE HELICITY, WHICH WOULD SUPPORT  
A CONTINUED THREAT FOR EMBEDDED SUPERCELLULAR STRUCTURES AND  
ASSOCIATED TORNADO POTENTIAL WITHIN THE CONVECTIVE LINE. THE  
PCPN AND COLD FRONT WILL PUSH OFFSHORE DURING SAT MORNING, WITH  
AT LEAST PARTIAL CLEARING FM WEST TO EAST VERY LATE TONIGHT THRU  
SAT MORNING. LOWS TONIGHT MAINLY IN THE UPPER 50S TO LOWER 60S.  
 

 
   
SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/
 
 
AS OF 440 PM EDT FRIDAY...  
 
MOST OF THE REGION WILL BECOME AT LEAST PARTLY SUNNY DURING SAT,  
AS PCPN PUSHES OUT TO SEA AND UPPER LOW PRESSURE REMAINS WEST OF  
THE AREA. A FEW ISOLATED SHOWERS COULD MOVE INTO EXTRM WRN  
COUNTIES LATE IN THE DAY. HIGHS ON SAT WILL RANGE FM THE MID 60S  
TO LOWER 70S. UPPER LOW PRESSURE WILL THEN MOVE INTO AND ACRS  
THE REGION SAT NIGHT INTO EARLY MON MORNING. THIS WILL RESULT IN  
MORE CLOUDS ALONG WITH A SLGT CHC TO CHC POPS FOR SHOWERS. MORE  
SUNSHINE WILL RETURN TO ALL AREAS DURING MON, AS THE UPPER LOW  
MOVES AWAY TO THE NE.  
 
LOWS SAT NIGHT IN THE UPPER 40S TO MID 50S. HIGHS ON SUN IN THE  
60S. LOWS SUN NIGHT IN THE MID 40S TO LOWER 50S. HIGHS ON MON IN  
THE UPPER 60S TO MID 70S.  
 

 
   
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/
 
 
AS OF 330 PM EDT FRIDAY...  
 
THE EXTENDED PERIOD BEGINS WITH THE UPPER TROUGH THAT WILL  
IMPACT THE REGION THIS WEEKEND FINALLY EXITING THE AREA AND A  
STRONGER UPPER LEVEL RIDGE BUILDING IN AND ACROSS THE  
SOUTHEASTERN US. AS THE RIDGE BUILDS IN, EXPECT TO SEE A PERIOD  
OF WARMER WEATHER AND ALSO DRIER CONDITIONS ON TUESDAY.  
 
THERE IS A GREAT DEAL OF UNCERTAINTY FROM WEDNESDAY THROUGH  
FRIDAY HOWEVER AS SEVERAL SHORTWAVE TROUGHS TRY TO BREAK DOWN  
THE SE RIDGE AND PUSH A SURFACE FRONT THROUGH THE AREA. THE  
MODELS ARE SHOWING LITTLE CONSISTENCY BETWEEN THEMSELVES AND  
LITTLE RUN TO RUN CONSISTENCY EITHER. THE 00Z ECMWF WAS QUICKER  
TO PUSH THE SURFACE FRONT SOUTH OF THE AREA AS IT WAS MORE  
PROGRESSIVE WITH THE UPPER LEVEL SHORTWAVE TROUGH AND HAD THE  
SURFACE FRONT SOUTH OF THE REGION BY THURSDAY BEFORE LIFTING IT  
BACK NORTH ON FRIDAY. THE 12Z GFS ON THE OTHER HAND WAS SLOWER  
TO MOVE THE FRONT THROUGH WAITING UNTIL THURSDAY NIGHT TO PUSH  
THE FRONT THROUGH AS A STRONGER NORTHERN STREAM TROUGH  
APPROACHES ON FRIDAY. THEN THE 12Z ECMWF COMPLETELY CHANGED  
THINGS BY BEING SO SLOW THAT IS NEVER HAS THE FRONT REACH THE  
AREA AND AMPLIFIES THE UPPER TROUGH OVER TEXAS AND HOLDS THE  
FRONT NORTHWEST OF THE AREA INTO FRIDAY NIGHT. SO CONFIDENCE IN  
THE OVER PATTERN IS LOW. FOR NOW, HAVE ADDED A GENERALLY LOW  
CHANCE OF SHOWERS INTO THE FORECAST FROM WEDNESDAY INTO FRIDAY  
AND IT WILL ALL BE DEPENDENT ON THE POSITION OF THE FRONT.  
 
FOR TEMPERATURES, HAVE GONE A TOUCH WARMER ON TUESDAY INTO  
WEDNESDAY WITH READINGS IN THE UPPER 70S TO THE LOWER 80S. BUT A  
TOUCH COOLER ON THURSDAY AND FRIDAY WITH READINGS IN THE MID  
70S. BUT IF THE FRONT DOES STAY TO THE NORTH, READINGS COULD BE  
A LITTLE WARMER TOWARD THE TAIL END OF NEXT WEEK. OVERNIGHT LOWS  
SHOULD STAY ON THE MILDER SIDE IN THE 50S ACROSS THE REGION.  
 

 
   
AVIATION /21Z FRIDAY THROUGH WEDNESDAY/
 
 
AS OF 350 PM EDT FRIDAY...  
 
SYNOPTIC SOUTHERLY WINDS AT 10-20 KNOTS WITH GUSTS TO AROUND 30  
KNOTS WILL CONTINUE INTO THIS EVENING AT THE TAF SITES, OUTSIDE  
OF SHOWERS/TSTMS IN ADVANCE OF A COLD FRONT. OTHERWISE, MULTIPLE  
ROUNDS OF SHOWERS/TSTMS WILL PREVAIL ACRS THE REGION FM LATE  
THIS AFTN INTO EARLY SAT MORNING, WITH LOCALIZED RESTRICTIONS  
TO MVFR (IFR?), AS THE FRONTAL BOUNDARY PUSHES INTO AND ACRS THE  
AREA. THE PCPN AND COLD FRONT WILL PUSH OFFSHORE DURING SAT  
MORNING, WITH VFR CONDITIONS RETURNING FOR THE REMAINDER OF SAT.  
 
OUTLOOK: UPPER LOW WILL BE SLOW TO MOVE INTO AND ACRS THE REGION  
SAT EVENING INTO EARLY MON MORNING. THIS WILL RESULT IN MORE  
CLOUDS (STILL MAINLY VFR CIGS), ESPLY OVER RIC/SBY/PHF, ALONG  
WITH THE SLGT OR SML CHC FOR SHOWERS.  
 

 
   
MARINE
 
 
AS OF 350 PM EDT FRIDAY...  
 
DEEP LOW PRESSURE WILL TRACK NNE OVER THE PIEDMONT LATE THIS  
AFTN AND EVENING WITH AN INTENSIFYING LLJ OVER THE MID-ATLANTIC  
COAST. A S WIND WILL INCREASE TO 20-25KT THROUGH THIS AFTN, WITH  
OCCASIONAL GUSTS TO ~35KT AS SHOWERS/TSTMS TRACK NNE ALONG THE  
WRN SHORE OF THE BAY. A S WIND WILL INCREASE TO 25-30KT THIS  
EVENING WITH THE POTENTIAL FOR 35-40KT GUSTS (AND POTENTIALLY  
STRONGER WITH CONVECTION LATER THIS EVENING, WHICH CAN BE  
HANDLED WITH SMWS). THE GALE WARNING HAS BEEN ADDED TO THE BAY,  
LOWER JAMES, AND NRN OCEAN AS OBSERVED GUSTS TO ~35KT HAVE  
INCREASED OVER THE PAST 1-2HRS. WAVES TO BUILD TO 4-5 FT ON THE  
CHESAPEAKE BAY, SEAS TO 7-10 FT (BY LATE TODAY INTO TONIGHT).  
WINDS ARE EXPECTED TO DIMINISH OVERNIGHT TONIGHT POST  
CONVECTION.  
 
LOW PRESSURE WILL BE SLOW TO EXIT THE REGION DURING THE  
WEEKEND. WILL MAINTAIN A S WIND 15-20 KT SATURDAY FOR MOST  
MARINE AREAS (AOB 15 KT ON THE RIVERS), BECOMING SW FOR SATURDAY  
NIGHT, SUNDAY WITH FURTHER LOWERING OF SPEEDS EXPECTED.  
 

 
   
TIDES/COASTAL FLOODING
 
 
AS OF 350 PM EDT FRIDAY...  
 
LATEST GUIDANCE DEPICTS POTENTIAL MINOR TIDAL FLOODING FOR THE  
BAY-SIDE OF THE LOWER MD ERN SHORE WHERE TIDAL DEPARTURES ARE  
EXPECTED TO AVERAGE 1.0-1.5FT MLLW. ADDITIONAL MINOR FLOODING  
IS POSSIBLE ALONG THE ALBEMARLE SOUND WITH A STRONG S WIND. A  
COASTAL FLOOD ADVISORY HAS BEEN ISSUED FOR THE MD ERN SHORE FROM  
MIDNIGHT TO 7 AM SATURDAY, AND A COASTAL FLOOD STATEMENT HAS  
BEEN ISSUED THROUGH 8 AM SATURDAY.  
 

 
   
AKQ WATCHES/WARNINGS/ADVISORIES
 
 
MD...FLASH FLOOD WATCH UNTIL 4 AM EDT SATURDAY FOR MDZ021>025.  
COASTAL FLOOD ADVISORY FROM MIDNIGHT TONIGHT TO 7 AM EDT  
SATURDAY FOR MDZ021>023.  
NC...FLASH FLOOD WATCH UNTIL 4 AM EDT SATURDAY FOR NCZ012>017-  
030>032-102.  
VA...FLASH FLOOD WATCH UNTIL 4 AM EDT SATURDAY FOR VAZ048-060>062-  
064>069-075>090-092-093-095>100-509>525.  
MARINE...GALE WARNING UNTIL 6 AM EDT SATURDAY FOR ANZ650-652-654-656-  
658.  
SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR ANZ635>637.  
GALE WARNING UNTIL 4 AM EDT SATURDAY FOR ANZ630>634-638.  
 

 
 

 
SYNOPSIS...TMG  
NEAR TERM...TMG  
SHORT TERM...TMG  
LONG TERM...ESS  
AVIATION...TMG  
MARINE...AJZ  
TIDES/COASTAL FLOODING...AKQ  
 
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