337  
FXUS61 KRNK 231511  
AFDRNK  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BLACKSBURG VA  
1111 AM EDT THU MAR 23 2017  
   
SYNOPSIS
 
 
HIGH PRESSURE WILL MOVE SOUTHEAST ACROSS OUR REGION TODAY AND SLIDE  
OFF THE COAST TONIGHT INTO FRIDAY. A WARMER SOUTHERLY FLOW WILL  
DEVELOP FRIDAY INTO THE WEEKEND AHEAD OF A SLOW MOVING COLD FRONT  
THAT WILL APPROACH THE REGION SUNDAY. A SERIES OF UPPER-LEVEL  
LOW PRESSURE AREAS WILL TRACK ACROSS THE CENTRAL AND SOUTHERN  
U.S. THROUGH NEXT WEEK KEEPING AN UNSETTLED WEATHER PATTERN IN  
PLACE.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
AS OF 1100 AM EDT THURSDAY...  
 
DRY AND COOL TODAY WITH PLENTY OF SUNSHINE. STRONG HIGH PRESSURE  
RESIDES FROM NY TO NC AND STARTING TO GET ON THE BACKSIDE OF THE  
HIGH, WHICH IS RESULTING IN INCREASED WINDS OVER THE MOUNTAINS  
OF WV INTO FAR SOUTHWEST VA, THOUGH GUSTS TO 25 MPH SEEMS  
HIGHEST FOR NOW. EXPECT THIN CIRRUS AT TIMES DUE TO UPPER  
NORTHWEST FLOW ALOFT.  
 
PREVIOUS DISCUSSION FROM EARLY MORNING...  
 
HIGH PRESSURE OVER WESTERN PENNSYLVANIA THIS MORNING WILL MOVE  
SOUTHEAST THIS AFTERNOON AND DRIFT EAST AND OFF THE MID-  
ATLANTIC COAST TONIGHT INTO FRIDAY. COOL EASTERLY FLOW WILL KEEP  
THE AREAS EAST OF THE BLUE RIDGE JUST AS COOL AS THE MOUNTAINS.  
HIGH TEMPERATURES THIS AFTERNOON WILL RANGE FROM THE MID 40  
ACROSS THE NORTHERN MOUNTAINS TO LOWER 50S IN THE PIEDMONT. THE  
FAR WESTERN MOUNTAINS MAY MAKE A RUN AT THE MID TO UPPER 50S.  
CLEAR TO PARTLY CLOUDY CONDITIONS ARE EXPECTED TONIGHT. A WARM  
FRONT WILL LIFT NORTHWARD INTO THE OHIO VALLEY LATE TONIGHT INTO  
FRIDAY MORNING. ANY SHOWERS ASSOCIATED WITH THE WARM ADVECTION  
AND WARM FRONT WILL REMAIN TO OUR NORTH. WITH DRY AIRMASS ACROSS  
OUR REGION, LEANED TOWARDS THE DRIER GFS/NAM SOLUTIONS OVER THE  
ECMWF WHICH CLIPS THE NORTHERN EDGE OF GREENBRIER AND BATH  
COUNTIES WITH SOME MOISTURE ABOUT 12Z FRIDAY. LOW TEMPERATURES  
WILL RANGE FROM THE MID 20S IN THE NORTHERN MOUNTAINS TO THE MID  
30S IN THE WESTERN MOUNTAINS.  
 

 
   
SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/
 
 
AS OF 400 AM EDT THURSDAY...  
 
A PATTERN TRANSITION WILL BE UNDERWAY AT THE BEGINNING OF THIS  
PERIOD TAKING US FROM THE PREDOMINANT NORTHWEST FLOW ALOFT WE  
HAVE BEEN IN FOR MUCH OF MARCH SO FAR TO A VERY ACTIVE,  
UNSETTLED ZONAL FLOW WITH NUMEROUS EMBEDDED SOUTHERN STREAM  
VIGOROUS UPPER-LEVEL LOWS. THIS PATTERN CHANGE WILL BRING  
FREQUENT RAIN CHANCES TO THE AREA, AND SOME THUNDERSTORMS AS  
WELL, ALONG WITH AN EXTENDED PERIOD OF UNSEASONABLY WARM  
TEMPERATURES. IN FACT, AFTER FRIDAY MORNING, WE MAY HAVE SEEN  
THE LAST OF ANY FREEZING TEMPERATURES AT MOST LOCATIONS IN THE  
RNK CWA FOR THE REST OF MARCH. LOOKING AT THE GLOBAL PICTURE,  
WE CAN SEE THE SUPPORT FOR THIS PATTERN AS A BROAD AREA OF LOW  
PRESSURE COVERING MUCH OF THE PACIFIC SENDS A STEADY STREAM OF  
DISTURBANCES EASTWARD INTO THE U.S. BY THE SAME TOKEN, THIS  
ZONAL FLOW WILL KEEP THE CANADIAN/ARCTIC AIR LOCKED UP NORTH AND  
INSTEAD SUPPLY THE U.S. WITH A STEADY STREAM OF PACIFIC-BASED  
AIR MASSES.  
 
FRIDAY WILL BE THE TRANSITION DAY AS THE CURRENT AREA OF COLD,  
DRY HIGH PRESSURE MOVES EAST OFF THE COAST ALLOWING A RETURN  
SOUTHERLY FLOW OF WARM, MOIST AIR FROM THE GULF TO EVOLVE ACROSS  
THE REGION. TEMPERATURES WILL BE ON THE ORDER OF 10-15 DEGREES  
WARMER THAN WHAT WILL BE SEEN ON THURSDAY.  
 
ON SATURDAY, A SHORT WAVE RIDGE ACROSS THE EASTERN U.S. WILL  
EVOLVE IN ADVANCE OF THE FIRST DEEP UPPER LOW TO LIFT OUT OF THE  
SOUTHERN PLAINS. THUS, SATURDAY WILL BE A WARM DAY WITH  
INCREASING CLOUDS AND POSSIBLY SOME LATE DAY SHOWERS ADVANCING  
FROM THE TENNESSEE VALLEY INTO FAR SOUTHWEST VA OR SOUTHERN WV.  
THE UPPER LOW WILL THEN TAKE A MORE NORTHWARD TRACK INTO THE  
OHIO VALLEY AND WEAKEN AS IT ENCOUNTERS THE UPPER RIDGE ALONG  
THE EASTERN SEABOARD. NONETHELESS, SUFFICIENT FORCING,  
INSTABILITY, AND MOISTURE WILL EXIST AS THIS SYSTEM ROTATES WITH  
A NEGATIVE TILT INTO THE OHIO VALLEY, FOR A GOOD CHANCE OF  
SHOWERS ACROSS THE REGION SUNDAY. THEREFORE, HAVE ADVERTISED  
LIKELY TO CATEGORICAL POPS SUNDAY. TEMPERATURES SUNDAY WILL BE  
JUST A TAD COOLER THANKS TO CLOUD COVER AND PRECIPITATION, BUT  
WILL REMAIN UNSEASONABLY MILD.  
 
THE MAIN QUESTIONS DURING THE PERIOD WILL BE QPF FOR SUNDAY AND  
THUNDER CHANCES. WITH REGARD TO QPF, MODELS ARE IN FAIRLY GOOD  
AGREEMENT THAT WE SHOULD SEE 1/2 TO 3/4 INCH OF RAIN SUNDAY WITH  
THIS FIRST SYSTEM. INSTABILITY IS MEAGER AND DYNAMICS ARE  
WEAKENING. HAVE INCLUDED A SLIGHT CHANCE OF THUNDER IN THE FAR  
WESTERN AREAS WHERE ACTIVITY FROM THE TN VALLEY COULD ARRIVE  
BEFORE WEAKENING. SEVERE WEATHER DOES NOT APPEAR TO BE AN ISSUE  
WITH THIS FIRST SYSTEM.  
 

 
   
LONG TERM /MONDAY THROUGH WEDNESDAY/
 
 
AS OF 430 AM EDT THURSDAY...  
 
THE NEXT IN A SERIES OF UPPER-LEVEL LOW PRESSURE AREAS WILL MOVE  
FROM THE SOUTHERN PLAINS INTO THE TENNESSEE VALLEY/CENTRAL  
APPALACHIANS LATE MONDAY INTO TUESDAY. WHILE THIS SYSTEM WILL  
AGAIN BE WEAKENING AS IT MOVES TOWARD THE WESTERN ATLANTIC UPPER  
RIDGE, IT WILL HAVE SOMEWHAT BETTER DYNAMICS AND INSTABILITY TO  
WORK WITH THAN THE SUNDAY SYSTEM. THEREFORE, HAVE INCLUDED A  
SLIGHT CHANCE OF THUNDER FOR ALL AREAS TUESDAY AFTERNOON. THIS  
STILL DOES NOT LOOK LIKE A SEVERE WEATHER SYSTEM, BUT SLIGHTLY  
BETTER POTENTIAL FOR SUCH THAN THE SUNDAY SYSTEM. RAINFALL  
AMOUNTS AGAIN APPEAR TO BE IN THE 1/2 TO 3/4 INCH RANGE OVER ALL  
WITH THIS EVENT.  
 
A QUIETER MIDWEEK PERIOD APPEARS IN ORDER AS THE NEXT UPPER-  
LEVEL SYSTEM DEEPENS AND SLOWS AS IT MOVES INTO TEXAS AND AN  
UPPER RIDGE AMPLIFIES ACROSS THE EASTERN U.S. A WEAK AREA OF  
HIGH PRESSURE FROM THE GREAT LAKES FILTERS INTO THE AREA FOR  
MIDWEEK. BY FRIDAY, THIS AFOREMENTIONED SYSTEM WILL MOVE INTO  
THE MID-ATLANTIC REGION AS YET ANOTHER UPPER-LEVEL LOW PRESSURE  
AREA MOVES FROM THE SOUTHWEST U.S. INTO TEXAS.  
 
TEMPERATURES WILL REMAIN UNSEASONABLY MILD THROUGH THE PERIOD  
WITH NO SIGNIFICANT INTRUSIONS OF CANADIAN AIR. A SLIGHT COOLING  
WILL BE NOTED MIDWEEK, BUT TEMPERATURES WILL STILL BE LEFT ABOVE  
NORMAL. LOOK FOR MAXIMUM TEMPERATURES MUCH OF THE WEEK IN THE  
60S WEST TO THE 70S EAST, WITH LOWS MAINLY IN THE 40S AND 50S.  
 

 
   
AVIATION /15Z THURSDAY THROUGH MONDAY/
 
 
AS OF 720 AM EDT THURSDAY...  
 
VFR CONDITIONS WILL CONTINUE THROUGH THE TAF VALID PERIOD AS A  
LARGE AREA OF CANADIAN HIGH PRESSURE DRIFTS ACROSS THE REGION,  
THEN MOVES OFF THE EAST COAST FRIDAY. MID-LEVEL WARM ADVECTION  
WILL RESULT IN AN INCREASE IN MID/HIGH CLOUDS AFTER 06Z, OTHERWISE  
JUST LOOKING FOR SCT CIRRUS THROUGH THE DAY TODAY. VISIBILITY  
WILL BE VFR THROUGH THE PERIOD WITH NO FOG DEVELOPMENT. WINDS  
WILL VEER AROUND FROM THE NORTHEAST TO THE SOUTHEAST THROUGH THE  
PERIOD AT SPEEDS OF 4-7KTS, GENERALLY LESS AFTER 00Z.  
 
HIGH CONFIDENCE IN CEILINGS AND VISIBILITIES THROUGH THE TAF  
VALID PERIOD.  
MEDIUM TO HIGH CONFIDENCE IN WIND SPEED/DIRECTION THROUGH THE  
TAF VALID PERIOD.  
 
EXTENDED AVIATION DISCUSSION...  
 
GOOD FLYING WEATHER IS EXPECTED TO LINGER INTO FRIDAY NIGHT BEFORE  
MOISTURE STARTS TO INCREASE OVER THE WEEKEND AHEAD OF AN UPPER-  
LEVEL LOW PRESSURE AREA MOVING NORTHEAST FROM THE SOUTHERN  
PLAINS. PRECIPITATION IS NOT EXPECTED UNTIL SUNDAY WHEN SUB-  
VFR CONDITIONS BECOME MORE OF A POSSIBILITY. OTHERWISE LOOKING  
AT OVERALL VFR TO START THE WEEKEND WITH MOST LOWER CIGS  
REMAINING WEST OF THE AREA UNTIL LATER SUNDAY AT THIS POINT.  
PERIODS OF UNSETTLED WEATHER WILL CONTINUE INTO THE FIRST HALF  
OF NEXT WEEK AS A SERIES OF UPPER-LEVEL LOWS TRACK FROM WEST TO  
EAST ACROSS THE U.S.  
 

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

 
 

 
SYNOPSIS...KK  
NEAR TERM...KK/RCS/WP  
SHORT TERM...RAB  
LONG TERM...PM/RAB  
AVIATION...KK/RAB  
 
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