801  
FXUS61 KLWX 190148  
AFDLWX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC  
848 PM EST THU JAN 18 2018  
   
SYNOPSIS
 
 
HIGH PRESSURE WILL BUILD SOUTH OF THE AREA THROUGH THE WEEKEND.  
A COLD FRONT WILL CROSS THE AREA EARLY NEXT WEEK.  
 

 
   
NEAR TERM /UNTIL 6 AM FRIDAY MORNING/
 
 
A 1031MB HIGH PRESSURE CENTER RESIDES OVER THE GULF COAST  
STATES THIS EVENING, EXTENDING ITS NORTHEASTERN FLANK OVER OUR  
REGION. THIS EXPANSIVE AREA OF HIGH PRESSURE IS RESPONSIBLE FOR  
CLEAR SKIES FOR MOST LOCATIONS RESIDING EAST OF THE MISSISSIPPI  
RIVER. WINDS HAVE BEEN SUBDUED FOR THE LAST FEW HOURS AND WILL  
CONTINUE TO TREND LIGHT TO CALM ACROSS THE MUCH OF THE AREA  
OVERNIGHT. COMBINE THIS WITH CLEAR SKIES, EXPECT PRIME  
RADIATIONAL COOLING CONDITIONS TONIGHT. WE'VE ALREADY SEEN SOME  
OF OUR FAVORED RADIATIONAL COOLING LOCATIONS DIP IN TO THE MID  
TO UPPER 20S EARLY THIS EVENING. WITH DEWPOINTS IN THE SINGLE  
DIGITS TO LOW TEENS ACROSS THE AREA, THIS LEAVES PLENTY OF ROOM  
FOR TEMPERATURES TO BOTTOM OUT IN THE MID TO UPPER TEENS FOR  
MOST, WITH LOCATIONS NEAR OUR CITY CENTERS HOLDING IN THE LOW TO  
MIDDLE 20S. ON GOING FORECAST IS IN GOOD SHAPE WITH NO MAJOR  
CHANGES NEEDED.  
 

 
   
SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/
 
 
WARM ADVECTION SHOULD BE UNDERWAY FRIDAY, WITH LITTLE TANGIBLE  
WEATHER. ASIDE FROM PERHAPS SOME HIGH CLOUDS, IT WILL LARGELY BE A  
TEMPERATURE FORECAST. READINGS SHOULD GET INTO THE 40S FRIDAY  
(WITHOUT THE WINDS) AND 50S SATURDAY. LOWS WILL DROP INTO THE 20S  
FRIDAY NIGHT AND NEAR FREEZING SATURDAY NIGHT.  
 
AS AN UPPER DISTURBANCE TRACKS ALONG THE GULF COAST SATURDAY-  
SATURDAY NIGHT, SOME MOISTURE COULD SPREAD NORTH WITH ISENTROPIC  
LIFT UP THE MOUNTAINS. AT THIS POINT, THERE IS LIGHT QPF (AT  
BEST)...SO POPS ARE SUBSEQUENTLY LOW (CHANCE). WILL NEED TO KEEP AN  
EYE ON TEMPERATURES THOUGH. BELIEVE THAT THERE WILL BE ENOUGH WARM  
ADVECTION TO PRECLUDE FREEZING RAIN, BUT A FEW GEFS ENSEMBLE MEMBERS  
DO HAVE SUBFREEZING AIR JUST EAST OF WHERE THE MEAGER POPS WILL BE.  
AND DETERMINISTIC OUTPUT ALSO DEPICT A CLOSE CALL. POPS ARE ONLY FOR  
THE WESTERN FRINGE ZONES, AND ARE ONLY 20-30%, BUT DID INTRODUCE  
RAIN OR FREEZING RAIN OVERNIGHT...JUST IN CASE.  
 

 
   
LONG TERM /SUNDAY THROUGH THURSDAY/
 
 
HIGH PRESSURE WILL BE NEAR THE SOUTH CAROLINA COAST SUNDAY, WITH A  
WARM FRONT LIFTING NORTHWARD TO OUR WEST. AN AREA OF LOW PRESSURE  
WILL DEVELOP ALONG THE TAIL-END OF THIS WARM FRONT OVER THE CENTRAL  
PLAINS. THE LOW IS EXPECTED TO MOVE TOWARD THE GREAT LAKES REGION  
SUNDAY NIGHT THROUGH MONDAY NIGHT. WITH THAT, THE WARM FRONT WILL  
BRING US A CHANCE FOR A RAIN SHOWERS ALONG THE MASON-DIXON REGION  
AND THE APPALACHIAN FRONT SUNDAY NIGHT AND MONDAY. THE INCREASED  
CHANCE FOR RAIN SHOWERS WILL BE MONDAY NIGHT WITH A COLD FRONT  
PASSAGE. TEMPERATURES WILL BE ABOVE NORMAL SUNDAY NIGHT THROUGH  
MONDAY NIGHT. HIGH TEMPERATURES COULD REACH THE 60S MONDAY AHEAD  
OF THE COLD FRONT.  
 
RAIN SHOWERS COULD LINGER ON TUESDAY ON THE BACK SIDE OF THE COLD  
FRONT. COLDER AND DRIER AIR WILL MOVE IN BEHIND THE FRONT AS WELL.  
TEMPERATURES WILL BE ABOUT 10 DEGREES COOLER THAN THE DAY BEFORE DUE  
TO FRONTAL PASSAGE.  
 
HIGH PRESSURE WILL REGAIN CONTROL OF THE REGION WITH THE CHILLY  
JANUARY AIR BUT PLENTY OF SUNSHINE WEDNESDAY THROUGH THURSDAY.  
 

 
   
AVIATION /01Z FRIDAY THROUGH TUESDAY/
 
 
VFR CONDITIONS WILL DOMINATE HEADING IN TO THE WEEKEND. LIGHT  
WINDS FORECAST OVERNIGHT IN TO FRIDAY, REMAINING AT 10 KNOTS OR  
LESS, RESIDING OUT OF THE WEST TO SOUTHWEST THROUGH SATURDAY  
NIGHT.  
 
VFR CONDITIONS CONTINUE SUNDAY THROUGH MIDDAY MONDAY. MVFR TO  
BRIEFLY IFR CONDITIONS POSSIBLE WITH RAIN SHOWERS LATE MONDAY  
AND MONDAY NIGHT.  
 

 
   
MARINE
 
 
WITH A RIDGE OF HIGH PRESSURE BUILDING OVER OUR REGION, LIGHT  
WINDS WILL PREVAIL OVERNIGHT WITH NO HEADLINES EXPECTED. WIND FLOW  
WILL BACK SOUTHWEST FRIDAY, AND WILL REMAIN THERE AT 10 KT OR  
LESS THROUGH MONDAY.  
 

 
   
LWX WATCHES/WARNINGS/ADVISORIES
 
 
DC...NONE.  
MD...NONE.  
VA...NONE.  
WV...NONE.  
MARINE...NONE.  
 

 
 

 
SYNOPSIS...HTS  
NEAR TERM...BKF  
SHORT TERM...HTS  
LONG TERM...KLW  
AVIATION...BKF/HTS/KLW  
MARINE...BKF/HTS/KLW  
 
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