Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 301954
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
354 PM EDT SAT MAY 30 2015

.SYNOPSIS...
HIGH PRESSURE OFFSHORE WILL MAINTAIN A VERY WARM AND HUMID AIR
MASS ACROSS THE REGION INTO SUNDAY. A COLD FRONT WILL APPROACH
FROM THE NORTHWEST LATE IN THE WEEKEND...BEFORE PUSHING SOUTH OF
THE AREA BY MONDAY...RESULTING IN MORE WIDESPREAD SHOWERS AND
THUNDERSTORMS LATER SUNDAY INTO MONDAY AFTERNOON. COOLER WEATHER
UNDER HIGH PRESSURE WILL BUILD IN BY THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /THROUGH SUNDAY/...
AS OF 250 PM EDT SATURDAY...

FOG WILL AGAIN FORM TONIGHT IN LOCATION THAT HAD RAIN SATURDAY
AFTERNOON AND EVENING. PATCHY DENSE FOG IS POSSIBLE NEAR AREA RIVERS
AND LAKES AS LONG AS THERE IS SOME PROLONGED CLEARING OVERNIGHT.

LOW PRESSURE WILL BE OVER THE OHIO VALLEY ON SUNDAY MORNING WITH A
COLD FRONT TRAILING FROM THE LOW INTO THE LOWER MISSISSIPPI VALLEY.
LOW LEVEL WINDS WILL BACK TO THE SOUTHEAST IN RESPONSE TO THIS
SYSTEM WHICH WILL ENHANCE CONVERGENCE ALONG THE BLUE RIDGE. EXPECT
THE HIGHEST PROBABILITY OF SHOWERS AND THUNDERSTORMS ALONG THE BLUE
RIDGE AND IN THE EXTREME WESTERN COUNTY WARNING AREA SUNDAY
AFTERNOON. ASIDE FROM DAYTIME HEATING AND INSTABILITY...NOT MUCH
OTHER LIFT OR SUPPORT FOR ANY ORGANIZED THUNDERSTORMS OR EXPANDED
COVERAGE THROUGH LATE SUNDAY.

NO CHANGE IN AIR MASS TONIGHT OR SUNDAY. MINIMUM AND MAXIMUM
TEMPERATURES WILL REMAIN 5 TO 10 DEGREES ABOVE NORMAL.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
AS OF 330 PM EDT SATURDAY

A COLD FRONT SITUATED NEAR THE OHIO RIVER AROUND SUNSET SUNDAY WILL
MAKE ONLY SLIGHT PROGRESS TOWARD OUR AREA THROUGH THE NIGHT. WITH
LOSS OF HEATING AND MINIMAL UPPER SUPPORT...HAVE LOWERED RAIN
CHANCES TO SLIGHT CHANCE WORDING BY DAWN MONDAY. WIDESPREAD CLOUD
COVER WILL HELP MAINTAIN OVERNIGHT TEMPERATURES IN THE LOW TO MID
60S AREAWIDE.

WEATHER FORECAST MODELS HAVE TRENDED SLOWER WITH THE APPROACH OF THE
COLD FRONT ON MONDAY...DELAYING ITS ARRIVAL INTO THE WESTERN HALF OF
OUR AREA UNTIL MONDAY NIGHT. REGARDLESS...STILL ANTICIPATE SCATTERED
SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE FORECAST AREA AS THE
SUPPORTING UPPER LEVEL TROUGH PASSES NORTH OF OUR AREA...WHILE
STRONG HEATING AHEAD OF THE FRONT WILL ADD INSTABILITY TO THE LOW
LEVELS. EXPECT TO SEE A FEW STRONG STORMS DURING THE AFTERNOON AND
EVENING...AS WELL AS THE POTENTIAL FOR LOCALLY HEAVY RAIN DUE TO
SLOW STORM MOVEMENT.

THE COLD FRONT WILL CONTINUE TO DRIFT EAST ACROSS OUR AREA ON
TUESDAY...ALTHOUGH THE TRULY DRIER AIR BEHIND THE FRONT WILL BE SLOW
TO ARRIVE. AS SUCH...WILL MAINTAIN A CHANCE OF SHOWERS AND
THUNDERSTORMS IN THE FORECAST...MORE SO ACROSS THE PIEDMONT WHERE
THE FRONT WILL BE SITUATED. HIGH PRESSURE WILL PASS FROM THE GREAT
LAKES TUESDAY NIGHT TOWARD NEW ENGLAND AND THE MID ATLANTIC...
HELPING TO PUSH THE FRONT FURTHER SOUTH AS THE HIGH WEDGES AGAINST
THE EASTERN FACE OF THE APPALACHIANS.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 330 PM EDT SATURDAY...

HIGH PRESSURE WILL REMAIN WEDGED AGAINST THE APPALACHIANS THROUGH
THE LATER HALF OF THE COMING WORKWEEK...MAINTAINING AN EAST TO
SOUTHEASTERLY WIND FLOW ACROSS OUR AREA. WITH AN UPPER LEVEL LOW
SPINNING ACROSS THE LOWER MISSISSIPPI VALLEY...AND LIGHT
SOUTHWESTERLY FLOW ALOFT PUSHING ALONG THE CENTRAL APPALACHIAN
CHAIN...DO NOT SEE THE COLD FRONT SINKING VERY FAR AWAY FROM OUR
AREA...PERHAPS STALLING ACROSS CENTRAL NORTH CAROLINA. AS SUCH...
WILL MAINTAIN A CHANCE FOR SHOWERS AND THUNDERSTORMS EACH DAY ACROSS
OUR AREA...WILL BETTER RAIN CHANCES ACROSS THE MOUNTAINS WEST OF
INTERSTATE 77...AS WELL AS OVER THE NORTH CAROLINA PIEDMONT.
INSTABILITY WILL BE MORE ON THE MARGINAL SIDE...SO BELIEVE THE
POTENTIAL FOR ANY STRONG THUNDERSTORMS WILL BE LOW...BUT WITH PLENTY
OF DEEP MOISTURE FLOWING NORTH ALONG THE APPALACHIAN CHAIN...WILL
HAVE WATCH FOR AREAS OF LOCALLY HEAVY RAIN EACH AFTERNOON AND
EVENING. EXPECT TEMPERATURES TO BE NEAR NORMAL FOR EARLY JUNE
AREAWIDE.

&&

.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
AS OF 125 PM EDT SATURDAY...

NWS RADAR SHOWED ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
WERE DEVELOP AT THE START OF THE 18Z TAF PERIOD WEST OF A LINE
FROM BUENA VISTA VIRGINIA TO ROANOKE TO TAZEWELL VIRGINIA. KLWB
HAS THE HIGHEST PROBABILITY OF HAVE THUNDERSTORMS BEFORE 00Z
TODAY BUT MAY ALSO NEED TO ADD TSRA OR VCTS IN FOR THE KROA AND
KBCB TAFS DEPENDING ON SHORT TERM RADAR TRENDS.

ONCE THE SUN SET THE COVERAGE OF SHOWERS AND THUNDERSTORMS WILL
DIMINISH. EXPECT PATCHY MVFR FOG OVERNIGHT. AIRPORT THAT GET RAIN
THIS AFTERNOON ALSO HAVE A BETTER CHANCE OF HAVING FOG AFTER
MIDNIGHT. SIMILAR TO SATURDAY MORNING FOG WILL BE SHALLOW AND WILL
DISSIPATE BY 14Z/10AM SUNDAY.

COLD FRONT WILL TRAIL ACROSS THE OHIO VALLEY ON SUNDAY. THIS WILL
TURN SURFACE AND LOW LEVEL WINDS TO THE SOUTHEAST. NO OTHER UPPER
SUPPORT FOR SHOWERS AND THUNDERSTORMS SUNDAY. ONCE AGAIN STORMS
WILL DEVELOP BETWEEN 16Z-18Z/NOON-2PM BUT PROBABILITY IS NOT HIGH
ENOUGH IN THAT TIME FRAME TO INCLUDE IN THE TAFS.

EXTENDED DISCUSSION...

THE SLOWLY APPROACHING FRONT WILL RESULT IN DEVELOPMENT OF MORE
WIDESPREAD CONVECTION INITIALLY ALONG THE BLUE RIDGE SUNDAY
AFTERNOON AND ACROSS MUCH OF THE WEST LATE IN THE DAY AS THE FRONT
APPROACHES. SOME OF THE CONVECTION MAY SPREAD EAST OF THE BLUE
RIDGE LATER IN THE AFTERNOON SO POTENTIAL FOR A LITTLE MORE IN THE
WAY OF PERIODIC SUB-VFR SUNDAY AFTERNOON/EVENING ESPCLY OVER THE
MOUNTAIN LOCATIONS.

THIS BOUNDARY SHOULD FINALLY SINK SOUTH INTO THE REGION BY MONDAY
RESULTING IN WIDESPREAD CONVECTION ESPCLY BLUE RIDGE EAST...WITH
ADDITIONAL ROUNDS OF SHRA/TSRA INTO AT LEAST MONDAY NIGHT BEFORE
THE BOUNDARY SINKS TO THE SOUTH. THIS SHOULD MAKE FOR MORE
FREQUENT PERIODS OF SUB-VFR FROM SUNDAY NIGHT INTO TUESDAY WITH
LOWER CIGS/VSBY REDUCTIONS DUE TO SHOWERS/STORMS DURING THE
DAY...AND IN FOG OVERNIGHT INTO THE EARLY MORNING HOURS EACH DAY.
LOWER MVFR/IFR CIGS ARE LIKELY BEHIND THE FRONT INTO THURSDAY WITH
EASTERLY FLOW AND WEDGING IN PLACE RESULTING IN MVFR CEILINGS.

&&

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

&&

$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...NF
LONG TERM...NF
AVIATION...AMS/JH/WERT



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