067  
FXUS61 KRNK 182301  
AFDRNK  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BLACKSBURG VA  
701 PM EDT SAT AUG 18 2018  
   
SYNOPSIS
 
 
A FRONTAL BOUNDARY WILL DRIFT SOUTH INTO THE REGION LATER  
TONIGHT INTO SUNDAY BEFORE STALLING, WHICH SHOULD KEEP PERIODS  
OF UNSETTLED WEATHER IN PLACE FOR THE REST OF THE WEEKEND.  
THE FRONT LIFTS BACK NORTH AS A WARM FRONT MONDAY AHEAD OF  
ANOTHER STRONGER COLD FRONT THAT SHOULD ARRIVE WITH MORE SHOWERS  
AND STORMS ON TUESDAY. HIGH PRESSURE WILL FOLLOW THE FRONT  
RESULTING IN COOLER AND DRIER WEATHER FOR THE MIDDLE OF NEXT  
WEEK.  

 
   
NEAR TERM /THROUGH SUNDAY/
 
 
AS OF 215 PM EDT SATURDAY...  
 
A WEAK COLD FRONT IS SLOWLY CROSSING OVER VIRGINIA, WHICH IS  
PROVIDING PREVALENT CLOUD COVER AND SHOWERS MOVING EASTWARD OVER  
THE BLUE RIDGE. THE 12Z RNK SOUNDING SHOWS A PRECIPITABLE WATER  
VALUE OF OVER 1.6 INCHES, SO THERE STILL REMAINS A THREAT OF  
LOCALIZED HEAVY RAIN. INSTABILITY CONTINUES TO BE WEAK OVERALL  
IN THE MODEL SOUNDINGS EXCEPT FOR EAST OF DANVILLE WHERE A HOLE  
IN CLOUD COVER DEPICTED IN VISIBLE SATELLITE ALLOWED SURFACE  
HEATING. A FEW THUNDERSTORMS HAVE JUST DEVELOPED IN THIS AREA  
AND WILL HEAD EASTWARD INTO CENTRAL VIRGINIA. THE SHOWER  
ACTIVITY SHOULD INCREASE OVER THE PIEDMONT THIS AFTERNOON, BUT  
THIS ACTIVITY WILL DECREASE SOMEWHAT OVER SOUTHEAST WEST  
VIRGINIA. POPS SHOULD REMAIN RATHER HIGH WITH HIGH TEMPERATURES  
REACHING THE 70S AND 80S.  
 
ANY CONVECTIVE ACTIVITY WILL GRADUALLY DIMINISH IN COVERAGE  
OVERNIGHT WITH POPS SLOWLY DECREASING TOWARD SUNDAY MORNING.  
SOME LOCALIZED PATCHY FOG IS POSSIBLE DUE TO THE WET GROUND AND  
LIGHT WINDS, BUT CONFIDENCE REMAINS HIGH THAT IT WILL BE A DAMP  
AND CLOUDY NIGHT WITH LOW TEMPERATURES IN THE LOWER 60S TO THE  
LOWER 70S. THE WEAK COLD FRONT SHOULD SAG SOUTHWARD TOWARD NORTH  
CAROLINA ON SUNDAY, WHICH WILL KEEP MOST OF THE AREA UNSETTLED.  
SHOWER AND THUNDERSTORM COVERAGE SHOULD INCREASE AGAIN BY THE  
AFTERNOON DUE TO THE PROXIMITY OF THE COLD FRONT THAT WILL  
EVENTUALLY STALL JUST SOUTH OF THE CWA. MORE BREAKS IN CLOUD  
COVER MAY ALLOW HIGH TEMPERATURES TO BE A FEW DEGREES HIGHER ON  
SUNDAY AS COMPARED TO SATURDAY.  
 

 
   
SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/
 
 
AS OF 300 PM EDT SATURDAY...  
 
THE SURFACE FRONTAL BOUNDARY WILL DRIFT SOUTH SUNDAY NIGHT INTO  
EARLY MONDAY. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL  
CONTINUE INTO SUNDAY EVENING, THEN TAPER OFF INTO THE  
OVERNIGHT. THE COMBINATION OF LIGHT WINDS AND LOW LEVEL HUMIDITY  
WILL RESULT IN PATCHY FOG LATE SUNDAY NIGHT INTO MONDAY MORNING.  
LOW TEMPERATURES SUNDAY NIGHT WILL RANGE FROM AROUND 60 DEGREES  
IN THE MOUNTAINS TO THE UPPER 60S IN THE PIEDMONT.  
 
A CLOSED UPPER LEVEL LOW ACROSS THE MID-MISSISSIPPI VALLEY WILL  
TRACK NORTHEAST AND REACH THE GREAT LAKES REGION BY MONDAY EVENING.  
THE LOW CENTER WILL CONTINUE TO ADVANCE NORTHEAST MONDAY NIGHT INTO  
TUESDAY NIGHT.  
 
ON MONDAY, LOW LEVEL SOUTHWEST FLOW WILL INCREASE ACROSS THE DEEP  
SOUTH, AND RESULT IN THE STALLED FRONT TO OUR SOUTH TO MOVE BACK  
ACROSS OUR AREA AS A WARM FRONT. THE PRECIPITATION CHANCES  
WILL INCREASE ACROSS OUR FORECAST AREA, WITH THE BEST OPPORTUNITY  
IN THE SOUTHWEST MOUNTAINS MONDAY AFTERNOON INTO MONDAY EVENING.  
HIGH TEMPERATURES MONDAY WILL VARY FROM THE LOWER 70S IN THE WEST TO  
THE MID 80S IN THE EAST. CLOUDY CONDITIONS WITH A FEW SHOWERS WILL  
CONTINUE MONDAY NIGHT. LOW TEMPERATURES MONDAY NIGHT WILL GENERALLY  
RANGE FROM THE LOWER 60S IN THE MOUNTAINS TO AROUND 70 DEGREES IN  
THE EAST.  
 
THE UPPER LOW'S ASSOCIATED COLD FRONT WILL APPROACH TUESDAY AND THEN  
CROSS THE AREA TUESDAY EVENING INTO TUESDAY NIGHT. NUMEROUS SHOWERS  
AND THUNDERSTORMS ARE EXPECTED TUESDAY AFTERNOON AND EVENING, THEN  
CONVECTION BEGINS TO WANE AFTER MIDNIGHT BEHIND THE PASSAGE OF THE  
FRONT. SOME OF THE THUNDERSTORMS COULD BE STRONG TO SEVERE WITH  
LOCALLY HEAVY RAINS. TUESDAY HIGH TEMPERATURES WILL BE COOLER WITH  
READINGS FROM AROUND 70 DEGREES IN THE WEST TO THE MID 80S IN THE  
EAST. LOW TEMPERATURES TUESDAY NIGHT WILL DROP TO THE UPPER 50S TO  
THE UPPER 60S.  
 

 
   
LONG TERM /WEDNESDAY THROUGH SATURDAY/
 
 
AS OF 300 PM EDT SATURDAY...  
 
A COLD FRONT WILL CONTINUE TO TRAVEL EAST WEDNESDAY, THEN A WAVE OF  
LOW PRESSURE ALONG THE BOUNDARY WILL CAUSE IT STALLED ALONG THE  
SOUTHEAST COAST WEDNESDAY NIGHT INTO THURSDAY. MEANWHILE, COOL  
CANADIAN HIGH PRESSURE WILL BUILD SOUTH ACROSS THE OHIO VALLEY AND  
THEN ACROSS THE MID ATLANTIC BY THURSDAY NIGHT. THE HIGH CENTER WILL  
SLIDE NORTHEAST INTO NEW ENGLAND FOR THE WEEKEND.  
 
ISOLATED TO SCATTERED DIURNAL SHOWERS AND THUNDERSTORMS WILL BE  
POSSIBLE WEDNESDAY. DRIER WEATHER IS EXPECTED THURSDAY INTO  
SATURDAY.  
 
THE ECMWF HAS TRENDED WEAKER WITH EVOLUTION OF THE SURFACE LOW  
YIELDING A SOLUTION MUCH CLOSER TO GFS. EASTERN U.S. HEIGHTS RISES  
EXPECTED AS THE COLD FRONT TO STALL NEAR THE SOUTHEASTERN AND GULF  
COASTS.  
 
COOLING TREND EXPECTED WEDNESDAY INTO THURSDAY, THEN TEMPERATURES  
MODERATE FOR THE WEEKEND.  
 

 
   
AVIATION /00Z SUNDAY THROUGH THURSDAY/
 
 
AS OF 700 PM EDT SATURDAY...  
 
SHOWERS AND ISOLATED STORMS HAVE DIMINISHED ACROSS THE REGION  
EARLY THIS EVENING WITH MOST NOW LINGERING ACROSS FAR SOUTHERN  
SECTIONS WITH THE PASSING WAVE AND UPSTREAM IN WEST VA NEAR THE  
ACTUAL SURFACE FRONT. SHORT TERM MODELS CONTINUE TO SHOW MUCH OF  
THIS COVERAGE ALSO FADING WITH LOSS OF HEATING, BUT APPEARS  
THAT A SHOWER OR STORM COULD MAKE IT INTO KBLF, AND PERHAPS  
KDAN WHERE LEAVING IN A VICINITY MENTION THROUGH LATE THIS  
EVENING. OTHERWISE LOOKING AT MAINLY VFR TO START ALTHOUGH CANT  
RULE OUT SOME PASSING MVFR CIGS BELOW A MID DECK CANOPY JUST  
AHEAD OF THE FRONT OVER THE NEXT FEW HOURS.  
 
LOW CLOUDS AND PATCHY FOG WILL LIKELY SPREAD OVER THE AREA  
LATER TONIGHT, ESPECIALLY AROUND KBLF GIVEN WEAK UPSLOPE AND  
PERHAPS KBCB/KLWB. ALTHOUGH THE GROUND WILL BE WET FROM RECENT  
RAINFALL, CLOUDY SKIES MAY KEEP THE FOG FROM GETTING DENSE SO  
FOG COVERAGE REMAINS LOW CONFIDENCE AT THIS POINT. HOWEVER GIVEN  
CURRENT TRENDS AND POTENTIAL FOR SOME BREAKS TO DEVELOP, DID  
ADD IN A BRIEF PERIOD OF TEMPO IFR AT KLWB/KBCB, AND OUT EAST  
IN SPOTS WHERE SOME STRATUS ALSO LOOKS POSSIBLE IN THE WAKE OF  
THE EARLIER HEAVY RAIN.  
 
BY SUNDAY MORNING, CONDITIONS SHOULD IMPROVE TO VFR AT  
KROA/KLYH/KDAN, BUT IT WILL TAKE SEVERAL HOURS MORE FOR  
KBLF/KLWB/KBCB TO FOLLOW SUIT. WITH THE COLD FRONT SAGGING  
TOWARD NORTH CAROLINA, ITS CLOSE PROXIMITY WILL TRIGGER MORE  
SHOWERS AND THUNDERSTORMS DURING THE AFTERNOON. MVFR/IFR  
CONDITIONS MAY OCCUR IN THE STRONGER ACTIVITY ESPCLY ACROSS THE  
MOUNTAINS WHERE INCLUDING A VCTS/VCSH MENTION FOR SUNDAY  
AFTERNOON PER LATEST MODEL CONSENSUS. SHOWERS MAY SPREAD EAST  
LATER IN THE DAY BUT TOO IFFY TO INCLUDE IN THE FORECAST AT  
KLYH/KDAN FOR NOW.  
 
EXTENDED DISCUSSION...  
 
ON MONDAY, THE STALLED FRONTAL BOUNDARY SHOULD START TO LIFT  
BACK NORTH OUT OF NORTH CAROLINA. THUS, MORE CHANCES OF SHOWERS  
AND THUNDERSTORMS WILL CONTINUE IN THE AFTERNOON ESPCLY SOUTHERN  
AND WESTERN SECTIONS. ADDITIONALLY, THE WET GROUND MAY ALLOW  
SOME MVFR/IFR CEILINGS AND FOG DURING MONDAY NIGHT, ESPECIALLY  
IN THE MOUNTAINS. THE FRONTAL BOUNDARY WILL MOVE NORTHWARD AS A  
WARM FRONT BY TUESDAY AND KEEP CONDITIONS UNSETTLED WITH  
POTENTIAL FOR MORE ORGANIZED CONVECTION LATER TUESDAY AHEAD OF  
THE NEXT STRONGER COLD FRONT. BY WEDNESDAY, THIS COLD FRONT WILL  
PUSH THROUGH THE MID ATLANTIC, AND HIGH PRESSURE SHOULD BUILD  
OVERHEAD BY THURSDAY. GOOD FLYING WEATHER WILL RETURN ONCE THE  
COOLER AND DRIER AIR MASS ASSOCIATED WITH THIS AREA OF HIGH  
PRESSURE ARRIVES.  
 

 
   
RNK WATCHES/WARNINGS/ADVISORIES
 
 
VA...NONE.  
NC...NONE.  
WV...NONE.  
 

 
 

 
SYNOPSIS...PW/JH  
NEAR TERM...PW  
SHORT TERM...KK  
LONG TERM...KK  
AVIATION...JH/PW  
 
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