609  
FXUS61 KLWX 230213 AAA  
AFDLWX  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC  
913 PM EST WED NOV 22 2017  
   
SYNOPSIS
 
 
HIGH PRESSURE WILL BUILD OVER THE AREA OVERNIGHT AND HOLD  
THROUGH FRIDAY. ANOTHER COLD FRONT WILL APPROACH OVERNIGHT  
FRIDAY INTO SATURDAY BEFORE PASSING THROUGH SATURDAY NIGHT. HIGH  
PRESSURE RETURNS FOR SUNDAY AND MONDAY.  
 

 
   
NEAR TERM /THROUGH THURSDAY/
 
 
WINDS WILL CONTINUE TO DIMINISH TONIGHT AS HIGH PRESSURE BUILDS  
FROM THE WEST. STRATOCUMULUS OVER THE MTNS ARE EXPECTED TO  
GRADUALLY DISSIPATE OVERNIGHT. OTHERWISE, CLEAR AND COLD  
TONIGHT WITH LOWS IN THE 20S IN MOST PLACES EXCEPT LOW 30S IN  
SOUTHERN MD AND CITY CENTERS.  
 

 
   
SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/
 
 
HIGH PRESSURE WILL CONTINUE TO BUILD OVERHEAD FOR THANKSGIVING  
DAY AND THANKSGIVING NIGHT, RESULTING IN BELOW NORMAL  
TEMPERATURES AND DRY CONDITIONS. HIGH PRESSURE WILL SHIFT  
EASTWARD OFF THE DELMARVA PENINSULA FRIDAY, ALLOWING WINDS TO  
TURN MORE SOUTHERLY, WHICH WILL HELP TEMPERATURES RETURN TO MORE  
SEASONABLE LEVELS WITH HIGHS IN THE LOW-MID 50S AND LOW  
TEMPERATURES FRIDAY NIGHT IN THE MID-UPPER 30S FOR MOST.  
 

 
   
LONG TERM /SATURDAY THROUGH WEDNESDAY/
 
 
A COLD FRONT WILL APPROACH FROM THE WEST ON SATURDAY, WITH  
AN UPPER TROUGH OVER THE EASTERN CONUS. SLIGHT RAIN CHANCES  
WILL BE POSSIBLE SATURDAY ACROSS THE WESTERN AND NORTHERN  
PORTIONS OF THE CWA AS THE PRIMARY ENERGY WILL REMAIN TO THE  
NORTH. AT THE SAME TIME A COASTAL LOW PRESSURE SYSTEM WILL BE  
MOVING NORTHEAST AWAY FROM THE CAROLINA COAST. AT THIS TIME,  
LITTLE TO NO IMPACT IS FORECAST FOR OUR AREA, HOWEVER SHOULD  
THIS LOW MOVE A FURTHER NORTHWESTWARD, SOUTHEASTERN PORTIONS OF  
THE REGION COULD SEE SOME RAIN SHOWERS. BEHIND THE FRONTAL  
PASSING, SNOW SHOWERS WILL BE POSSIBLE ALONG THE TYPICAL HIGHER  
TERRAIN LOCATIONS, WITH LITTLE TO NO ACCUMULATION EXPECTED.  
 
SURFACE HIGH PRESSURE BUILDS ON SUNDAY AS AN UPPER TROUGH AXIS  
MOVES EAST OF OUR CWA. CHILLY, BREEZY, AND MOSTLY DRY  
CONDITIONS WILL PREVAIL AS ANY REMAINING UPSLOPE SNOW SHOWERS  
WILL WANE. SUNDAY WILL HIGHLIGHT COLDER THAN AVERAGE  
TEMPERATURES, WITH MOST LOCATIONS NOT GETTING OUT OF THE 40S,  
AND OVERNIGHT LOWS SUNDAY NIGHT SIMILAR TO TONIGHT. MONDAY WILL  
SEE HIGH PRESSURE MOVE EASTWARD FROM THE OHIO VALLEY, MIGRATING  
OFF THE COAST LATE MONDAY. WITH THE UPPER LEVEL TROUGH JUST  
EXITING THE REGION, TEMPERATURES WILL BE SLIGHTLY WARMER MONDAY,  
YET STILL BELOW AVERAGE FOR LATE NOVEMBER. DRY CONDITIONS  
EXPECTED.  
 
SOUTHWEST FLOW RETURNS ON TUESDAY THANKS TO THE MIGRATION OF  
THE HIGH TO OUR EAST, RETURNING TEMPERATURES TO MID-UPPER 50S,  
AND BREACHING THE 60 DEGREE MARK ON WEDNESDAY. MODELS ARE IN A  
BIT OF A DISAGREEMENT WITH AN APPROACHING COLD FRONT WEDNESDAY,  
SO WILL CONTINUE TO MONITOR THIS SITUATION OVER THE NEXT COUPLE  
OF DAYS TO IRON OUT THE DETAILS AND TIMING.  
 

 
   
AVIATION /02Z THURSDAY THROUGH MONDAY/
 
 
VFR CONDITIONS WILL PREVAIL ACROSS ALL THE TERMINALS FOR  
THANKSGIVING DAY AND FRIDAY AS HIGH PRESSURE BUILDS OVERHEAD.  
 
MAINLY VFR CONDITIONS EXPECTED SATURDAY, WITH PRECIPITATION  
POSSIBLE LATER THAT DAY AS A COLD FRONT APPROACHES THE AREA.  
POTENTIAL EXISTS FOR PERIODS OF MVFR CONDITIONS SATURDAY  
AFTERNOON AND EVENING. DRIER/VFR CONDITIONS EXPECTED SUNDAY  
INTO MONDAY OVER THE TERMINALS.  
 

 
   
MARINE
 
 
A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE COASTAL WATERS  
TONIGHT AS GUSTY NORTHWESTERLY WINDS WILL START TO SUBSIDE  
TOWARD THURSDAY MORNING. NO HEADLINES EXPECTED THEREAFTER  
THROUGH FRIDAY NIGHT AS HIGH PRESSURE BUILDS IN OVERHEAD.  
 
WINDS ARE EXPECTED TO STAY BELOW THRESHOLD ON SATURDAY  
INTO SATURDAY NIGHT AS COLD FRONT MOVES THROUGH THE AREA. WINDS  
WILL INCREASE ON SUNDAY INTO SUNDAY NIGHT, THEREFORE SMALL  
CRAFT ADVISORIES WILL BE POSSIBLE. WINDS WILL DECREASE BELOW  
SCA THRESHOLD ON MONDAY.  
 

 
   
LWX WATCHES/WARNINGS/ADVISORIES
 
 
DC...NONE.  
MD...NONE.  
VA...NONE.  
WV...NONE.  
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST THURSDAY FOR ANZ531>534-  
537-539>541-543.  
SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR ANZ530-  
535-536-538-542.  
 

 
 

 
UPDATE...LFR  
PRODUCTS...BKF/IMR  
 
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