859  
FXUS61 KLWX 220754  
AFDLWX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC  
354 AM EDT MON OCT 22 2018  
   
SYNOPSIS
 
 
HIGH PRESSURE WILL MOVE ACROSS THE AREA TODAY THEN PUSH OFFSHORE  
TONIGHT. A COLD FRONT, APPROACHING FROM THE GREAT LAKES, WILL  
CROSS THE REGION TUESDAY. A SECOND AREA OF HIGH PRESSURE WILL  
DEVELOP AND PERSIST THROUGH THE SECOND HALF OF THE WEEK. LOW  
PRESSURE MAY APPROACH THE AREA FROM THE SOUTHEASTERN U.S. OR  
TENNESSEE VALLEY BY NEXT WEEKEND.  
 

 
   
NEAR TERM /UNTIL 6 PM THIS EVENING/
 
 
CLEAR SKIES AND GREAT RADIATIONAL COOLING WILL LEAD TO SOME  
AREAS OF FROST AND OTHER AREAS OF FREEZING TEMPERATURES EARLY  
THIS MORNING. TEMPERATURES WILL BOTTOM OUT IN THE 30S AREAWIDE,  
EXCEPT WHERE THE GROWING SEASON HAS ALREADY ENDED...WHERE WE  
HAVE SOME PATCHES OF FROST. TEMPERATURES IN THESE AREAS WILL  
DROP INTO THE 20S.  
 
HIGH PRESSURE WILL SLIDE OFFSHORE THIS AFTERNOON. A MODERATING  
TREND IN TEMPERATURES ARE EXPECTED TO BEGIN THIS AFTERNOON.  
HIGH TEMPERATURES WILL REACH THE 50S, WITH PERHAPS SOME INCREASE  
IN MID- UPPER LEVEL CLOUD COVER.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/
 
 
HIGH PRESSURE TO THE EAST WILL HAVE A BIG INFLUENCE THIS  
EVENING AND OVERNIGHT WITH LOW TEMPERATURES DROPPING INTO THE  
40S.  
 
A COLD FRONT WILL DROP SOUTHEASTWARD THROUGH TUESDAY. THE  
ATMOSPHERE WILL BE TOO DRY TO PRODUCE ANY PRECIPITATION. MOSTLY  
CLEAR AND COOL TUESDAY NIGHT.  
 
BREEZY NORTHWEST WINDS WILL CONTINUE USHERING IN A REINFORCING  
SHOT OF COOL AIR WEDNESDAY INTO WEDNESDAY NIGHT AS HIGH  
PRESSURE BUILDS TOWARD THE MID-ATLANTIC FROM THE GREAT LAKES.  
 

 
   
LONG TERM /THURSDAY THROUGH SUNDAY/
 
 
ON THURSDAY, HIGH PRESSURE WILL CONTINUE TO BE IN PLACE OVER THE  
REGION AS A WEAK UPPER LEVEL RIDGE MOVE TO THE NORTH. SKIES WILL  
REMAIN MOSTLY CLEAR WITH WINDS CONTINUING OUT OF THE NORTH. DRY  
CONDITIONS EXPECTED WITH ONLY LIGHT WINDS. DAYTIME TEMPERATURES WILL  
CONTINUE TO BE BELOW AVERAGE IN THE UPPER 30S TO UPPER 40S.  
OVERNIGHT TEMPERATURES THURSDAY INTO FRIDAY, WILL BE CHILLY IN THE  
UPPER 20 AND INTO THE 30S.  
 
FRIDAY INTO SATURDAY, THE UPPER LEVEL RIDGE TO THE NORTH WILL  
START TO BREAK DOWN AS A UPPER LEVEL TROUGH BUILDS INTO THE  
TENNESSEE RIVER VALLEY AND THE SMOKEY MOUNTAINS. A BROAD UPPER  
LEVEL TROUGH WILL BE POSITIONED OVER EASTERN CANADA AND NORTHERN  
MAINE. THE UPPER LEVEL TROUGH OVER TENNESSEE AND KENTUCKY IS  
FORECAST TO BROADEN AND EXPAND FURTHER SOUTHWARD INTO  
MISSISSIPPI AND ALABAMA. THIS WILL LEAD TO A TAPPING OF THE WARM  
AND MOIST AIR FROM THE GULF MEXICO. THE MODELS ARE POINTING TO  
A LOW PRESSURE SYSTEM FORMING OVER THE GULF OF MEXICO ON  
THURSDAY AND MOVING EAST TO NORTHEASTWARD TOWARD FLORIDA AND  
GEORGIA EARLY ON FRIDAY. THIS LOW PRESSURE SYSTEM IS EXPECTED TO  
GET CAUGHT UP ON THE EAST SIDE OF THE UPPER LEVEL TROUGH AND  
MOVE NORTHWARD ALONG THE EASTERN SEA BOARD. BOTH THE 00Z GFS AND  
EURO AGREE THAT A COASTAL STORM WILL FORM AND MOVE NORTHWARD  
ALONG THE EAST COAST. THE GFS TAKES THE UPPER LEVEL TROUGH AND  
KICKS IT EASTWARD FORCING THE COASTAL STORM FURTHER OFF THE  
COAST WHILE THE EURO KEEP THE TROUGH FURTHER INLAND OVER  
ARKANSAS AND TENNESSEE. THE EURO IS WETTER AND FASTER THAN THE  
GFS. THE EURO BRINGS THE COASTAL STORM NORTHWARD AND MOVES  
PRECIPITATION INTO OUR REGION BY 18Z (2PM) ON FRIDAY. THE GFS  
BRINGS THE OUTER BANDS OF PRECIPITATION INTO THE REGION AROUND  
6Z (2AM) SATURDAY MORNING AND REMAINS FURTHER OFF THE COAST  
LEADING TO LESSER RAIN EVENT. BOTH MODELS AGREE THAT SOME  
SEMBLANCES OF PRECIPITATION WILL LIKELY OCCUR ON SATURDAY WITH  
THERE BEING A CHANCE FOR PRECIPITATION STARTING SOMETIME LATE  
FRIDAY AFTERNOON INTO EVENING. THE 1000 TO 500MB THICKNESSES  
SEEM TO INDICATE THAT THIS WEATHER EVENT SHOULD BE MAINLY A RAIN  
EVENT WITH SOME SNOW POTENTIAL LATE SATURDAY INTO SUNDAY FOR  
THE HIGHER ELEVATION AREAS. A SLIGHT WARM UP WILL OCCUR FRIDAY  
INTO SATURDAY AS WINDS BECOME MORE SOUTHERLY.  
 
SUNDAY, THE COASTAL STORM WILL SHIFT FURTHER NORTHEASTWARD OUT OF  
OUR AREA. SOME LINGERINGS RAIN AND SNOW SHOWERS OVER THE HIGHER  
ELEVATIONS WILL BE POSSIBLE ON SUNDAY. THE GFS TRIES TO BRING A  
SECONDARY COLD FRONT SUNDAY AFTERNOON WHILE THE EURO TRIES TO KEEP  
THIS BOUNDARY MAINLY DRY. WINDS WILL DEPEND ON THE POSITION OF THE  
COASTAL LOW BUT THEY SHOULD BE MAINLY OUT OF THE EAST TO SOUTHEAST.  
 

 
   
AVIATION /08Z MONDAY THROUGH FRIDAY/
 
 
VFR CONDITIONS EXPECTED FOR THE NEXT FEW DAYS AS HIGH PRESSURE  
PASSES OVERHEAD AND A DRY COLD FRONT CROSSES THE TERMINALS  
TUESDAY.  
 
A SOUTHERLY FLOW WILL DEVELOP TODAY INTO TONIGHT WITH HIGH  
PRESSURE PUSHING TO THE EAST.  
 
WINDS WILL TURN WEST AGAIN ON TUESDAY AS A COLD FRONT CROSSES  
THE TERMINALS. HOWEVER, MOISTURE IS SHALLOW. WHILE THERE SHOULD  
BE A PERIOD OF CEILINGS LATE TUESDAY, THOSE CIGS SHOULD STILL BE  
VFR.  
 
MAINLY VFR WED AND WED NIGHT IN A NORTHWEST FLOW.  
 
ON THURSDAY, HIGH PRESSURE WILL CONTINUE TO BE IN PLACE OVER THE  
REGION. WINDS WILL BE OUT OF THE NORTH. SKIES WILL BE MOSTLY CLEAR  
WITH VFR CONDITIONS EXPECTED.  
 
FRIDAY, WINDS WILL SLOWLY BECOME SOUTHERLY BUT REMAIN LIGHT. SKIES  
WILL BE MOSTLY CLEAR TO START THE DAY BUT CLOUD COVER WILL INCREASE  
INTO THE AFTERNOON PERIODS. RAIN WILL POTENTIAL LATE FRIDAY  
AFTERNOON INTO EVENING FOR CENTRAL VIRGINIA. VFR CONDITIONS EXPECTED.  
 

 
   
MARINE
 
 
WINDS WILL GRADUALLY DIMINISH EARLY TODAY AND BECOME LIGHT THIS  
AFTERNOON.  
 
IN THE WAKE OF THE DEPARTING HIGH, GUIDANCE ATTEMPTING TO MIX  
SOME 20 KT GUSTS DUE TO SOUTHERLY CHANNELING IN THE MAIN CHANNEL  
OF THE BAY. A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR TONIGHT.  
 
BETTER MIXING/OPPORTUNITY FOR SMALL CRAFT ADVISORY CONDITIONS  
COMES LATE TUESDAY IN THE WAKE OF A PASSING COLD FRONT. GUSTY  
NW WINDS OF 20 TO 30 KNOTS ARE LIKELY THROUGH WEDNESDAY BEHIND  
THIS FRONT.  
 
LIGHT WINDS OUT OF THE NORTH WITH MOSTLY CLEAR SKIES ON THURSDAY.  
 
ON FRIDAY, WINDS WILL BE SOUTHERLY WITH INCREASING CLOUDS. RAIN WILL  
BE POSSIBLE LATE FRIDAY AFTERNOON INTO EVENING FOR THE SOUTHERN  
CHESAPEAKE BAY AREAS.  
 

 
   
TIDES/COASTAL FLOODING
 
 
WATER LEVELS SHOULD BEGIN TO GRADUALLY RECOVER TO NEAR  
ASTRONOMICAL NORMS BY TUESDAY. WATER WILL SLOSH BACK UP THE BAY  
WHEN WINDS GO LIGHT TODAY. WHILE THIS IS NOT EXPECTED TO CAUSE  
ANY FLOODING ISSUES, ANOMALIES COULD OSCILLATE TO NEAR OR A  
LITTLE ABOVE ASTRO NORMS QUICKER THAN CURRENTLY FORECAST.  
 

 
   
LWX WATCHES/WARNINGS/ADVISORIES
 
 
DC...FROST ADVISORY UNTIL 10 AM EDT THIS MORNING FOR DCZ001.  
MD...FREEZE WARNING UNTIL 10 AM EDT THIS MORNING FOR MDZ003-004-503.  
FROST ADVISORY UNTIL 10 AM EDT THIS MORNING FOR MDZ005-006-011-  
013-014-016>018-504>508.  
VA...FREEZE WARNING UNTIL 10 AM EDT THIS MORNING FOR VAZ025-036>040-  
050>052-055-056-501-502-505>508.  
FROST ADVISORY UNTIL 10 AM EDT THIS MORNING FOR VAZ053-054-057.  
WV...NONE.  
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT EARLY THIS MORNING FOR  
ANZ532>534-537-540-541-543.  
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EDT  
TUESDAY FOR ANZ531>534-537-539>543.  
 

 
 

 
SYNOPSIS...KLW  
NEAR TERM...KLW  
SHORT TERM...KLW  
LONG TERM...JMG  
AVIATION...KLW/JMG  
MARINE...KLW/JMG  
TIDES/COASTAL FLOODING...KLW  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab VA Page
The Nexlab MD Page
The Nexlab WV Page Main Text Page