Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000
FXUS61 KRNK 301513
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1113 AM EDT SAT AUG 30 2014

.SYNOPSIS...
A FRONT WILL MOVE NORTH AND DISSIPATE OVER THE MID ATLANTIC
REGION BY SUNDAY. A LOW PRESSURE SYSTEM WILL MOVE ACROSS THE GREAT
LAKES TONIGHT AND SUNDAY WITH A COLD FRONT TRAILING FROM THE UPPER
MISSISSIPPI VALLEY TO THE CENTRAL PLAINS BY SUNDAY NIGHT.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1100 AM EDT SATURDAY...

WEAK FRONT NOW LIES FROM NE WV SOUTHEAST INTO THE TIDEWATER. MSAS
ANALYSIS DEPICTED BEST THETA-E RIDGING OVER ERN KY INTO WV. SKIES
HAD CLEARED IN THE WEST WHILE THE EAST STAYED CLOUDY. SHOULD SEE
THINGS SCATTER OUT WITH THE SUN INCREASING THE EVAPORATION OF THE
LOW CLOUDS. THIS ALREADY BEING SEEN ON VIS SATELLITE EAST OF THE
BLUE RIDGE.

QUESTION THROUGH THE AFTERNOON WILL BE SHOWER CHANCES. NOT THAT
IMPRESSED WITH THE THREAT. APPEARS ALL THE BEST LIFT AND UPPER
SUPPORT WILL STAY ON THE WEST SIDE OF THE APPALACHIANS.
HOWEVER...THERE SHOULD BE AMPLE LOW LVL MOISTURE AND DIFFERENTIAL
HEATING TO SPARK ISOLATED SHOWERS AND STORMS. RIGHT NOW APPEARS
THIS WILL BE BEST CENTERED FROM THE WV MTNS EAST TO NORTH OF THE
ROANOKE RIVER. STILL ONLY ISOLATED COVERAGE. STICKY/HUMID WITH
HIGHS RANGING FROM THE LOWER TO MID 80S WEST TO AROUND 90
SOUTHEAST. THOSE OUTDOORS ON THIS HOLIDAY WEEKEND SHOULD DRINK PLENTY
OF WATER AND USE SUNSCREEN.

PREVIOUS VALID DISCUSSION...


UPPER RIDGE AXIS IS JUST OFF THE SOUTHEAST COAST BY TONIGHT. BROAD
SOUTHWEST FLOW FROM THE LOWER MISSISSIPPI VALLEY TO THE EASTERN GREAT
LAKES TONIGHT. THE SHORT WAVE COMING OUT OF THE NORTHERN GULF AND
THE BEST Q-V FORCING ALONG THE APPROACHING COLD FRONT WILL STILL BE
WEST OF THE FORECAST AREA BY SUNDAY MORNING. MID AND HIGH CLOUDS
WILL COVER THE WESTERN COUNTY WARNING AREA OVERNIGHT...THEN
INCREASING PROBABILITY OF PRECIPITATION IN THE FAR WEST. WITH THE
INCREASING CLOUDS AND SINCE THE FORECAST AREA WILL BE WELL WITHIN
THE WARM SECTOR TONIGHT...NOT MUCH DROP IN TEMPERATURES IS EXPECTED.
USED THE WARMER GUIDANCE FOR OVERNIGHT LOWS.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 310 AM EDT SATURDAY...

A STUBBORN UPPER LEVEL RIDGE WILL HUG THE SOUTHEASTERN COAST LONGER
THAN PREVIOUSLY EXPECTED. FROM A MODEL STAND POINT...THIS UPPER
RIDGE IS ALSO FARTHER INLAND...WHICH WILL LOWER THE CHANCE OF
SHOWERS AND THUNDERSTORMS AS THE SHORT WAVE TRACK IS PUSHED
WESTWARD. THE LATEST 00Z MODELS TRACKS A TROPICAL SHORT WAVE ON THE
OUTER RINGS OF THE RIDGE ACROSS EASTERN TENNESSEE AND CENTRAL
KENTUCKY SUNDAY MORNING...THEN OVER THE OHIO VALLEY IN THE
AFTERNOON. AS THIS SHORT WAVE MOVES OVER THE OHIO VALLEY IN THE
AFTERNOON...MID LEVEL CAPPING WEAKENS ALLOWING STORMS TO GENERATE
ALONG OUT FLOW BOUNDARIES AND IN MODEST INSTABILITIES. WITH THE
STRONGEST LOW LEVEL JET REMAINING OVER THE TENNESSEE AND OHIO
VALLEYS...DISORGANIZED PULSE-LIKE STORMS ARE EXPECTED OVER THE
MOUNTAINS IN THE AFTERNOON AND MAY DRIFT EAST OF THE BLUE RIDGE IN
THE EVENING...IF THE RIDGE DOES JOG TO THE SOUTHEAST. THERE WILL
ALSO BE A LEE TROUGH OVER THE PIEDMONT THAT MAY HELP FIRE STORMS
EAST OF THE BLUE RIDGE DURING THE LATE AFTERNOON AND EVENING HOURS.
CAN NOT RULE OUT THE CHANCE FOR A FEW STORMS TO BECOME SEVERE WHERE
THE CAP IS THE WEAKEST...MOUNTAIN EMPIRE TO THE BLUEFIELD RICHLANDS
AREA. SINCE THE MODELS HAVE MOVED ORGANIZED CONVECTION TO THE
WEST...LOWERED POPS ESPECIALLY IN THE EAST. SINCE THE CHANCES OF
SHOWERS IS LOWER AND SCATTERED IN NATURE...INCREASE TEMPERATURES
ACROSS THE MOUNTAINS INTO THE MID 80S AND U80S-L90S EAST OF THE BLUE
RIDGE.

ON MONDAY...MODELS ONCE AGAIN DRIFT UPPER LEVEL RIDGE TO THE
SOUTH...PLACING THE OUTER RINGS ACROSS THE FORECAST AREA. A WEAK
SHORT WAVE IS EXPECTED TO TRACK ALONG THE SOUTHERN APPALACHIANS
BRING A CHANCE FOR SHOWERS AND THUNDERSTORMS TO THE AREA MONDAY.
ONCE THIS SHORT WAVES TRACKS NORTH OF THE AREA...POSSIBLY BY EARLY
AFTERNOON...SURFACE HIGH PRESSURE WILL BUILD ACROSS THE REGION
MONDAY NIGHT. WITH THE AREA REMAINING IN A MUGGY AIR MASS...PATCHY
DENSE FOG IS LIKELY FOR MOUNTAIN VALLEYS. IF SHOWERS ARE PRIMARILY
DURING THE MORNING...MONDAY AFTERNOON TEMPERATURES WILL WARM INTO
THE MID 80S IN THE WEST TO U80S-L90S EAST OF THE BLUE RIDGE.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 330 PM FRIDAY...

FLAT UPPER RIDGE IS EXPECTED TO DOMINATE OUR MID-WEEK WEATHER
PATTERN ACROSS THE CENTRAL APPALACHIAN AND MID-ATLANTIC REGION. THIS
SHOULD MAINTAIN SUMMER-LIKE TEMPERATURES THROUGH THE ENTIRE PERIOD
WITH HIGHS NEAR 90F IN THE PIEDMONT AND MID-80S IN THE MOUNTAINS
ALONG WITH NIGHT-TIME LOWS IN THE 60S TO LOW 70S. COULD END UP BEING
ONE OF THE WARMEST WEEKS OF THE SUMMER EVEN AS THE SO-CALLED
METEOROLOGICAL SUMMER ENDS ON AUGUST 31. PRECIPITATION WILL ALSO
GENERALLY BE OF SUMMER-LIKE CHARACTER WITH DIURNALLY DRIVEN
CONVECTION PROVIDING THE BEST CHANCES FOR RAINFALL. WEDNESDAY
AFTERNOON LOOKS LIKE THE MOST PROMISING DAY FOR STORMS AS WEAK
FRONTAL BOUNDARY PUSHES ACROSS THE CWA. THURSDAY AND FRIDAY LIKELY
TO BE DRIER ALTHOUGH WIDELY SCATTERED SHOWERS STILL POSSIBLE.

&&

.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
AS OF 730 AM EDT SATURDAY...

BROAD AREA OF STRATUS HAD SPREAD WEST ACROSS THE REGION. THE
WESTERN EDGE WAS CLOSE TO KLWB AND KBLF...WITH A SMALL WHOLE THAT
JUST CLOSED RIGHT OVER THE KROA AIRPORT. KBLF AND KLWB SHUD
WILL MAINTAIN VFR CLOUDS.

FOR KBCB/KROA/KDAN AND KLYH IMPROVEMENT IN CEILINGS WILL BE SLOW
THIS MORNING AS A WEAK FRONT LIFTS NORTH THROUGH THE AREA. ONLY
MEDIUM CONFIDENCE AS TO WHEN CEILINGS WILL FINALLY GET BACK TO
VFR. THE THREAT OF SHOWERS AND THUNDERSTORMS THROUGH THE TAF
PERIOD REMAINS LOW ENOUGH TO KEEP OUT OF THE FORECAST FOR NOW.

EXPECT CLOUD COVER TO BE TOO EXTENSIVE TONIGHT FOR FOG
FORMATION...ESPECIALLY IN THE MOUNTAINS. MODELS SUGGESTED THAT LOW
CLOUDS...WITH IFR CEILINGS...MAY REFORM IN THE PIEDMONT. THIS
WOULD MOST LIKELY IMPACT KLYH AND KDAN VERY LATE IN THE TAF
FORECAST PERIOD. CONFIDENCE TOO LOW AT THIS TIME TO INCLUDE IN
THE FORECAST.

EXTENDED DISCUSSION...

ANY ISOLATED OR SCATTERED SHOWERS AND STORMS WILL BE MAINLY
ALONG AND NORTH OF A KHSP-KFVX LINE THIS EVENING...JUST SOUTH OF
THE AGAIN STALLED FRONTAL BOUNDARY.

LATE TONIGHT THROUGH SUNDAY EVENING AN AREA OF LOW PRESSURE WILL
HEAD EASTWARD THROUGH THE GREAT LAKES REGION TOWARD NEW ENGLAND.
ITS ASSOCIATED COLD FRONT WILL SWEEP THROUGH THE REGION BRINGING A
GENEROUS COVERAGE OF SHOWERS AND SOME STORMS. SUB-VFR CONDITIONS
ARE EXPECTED TO ACCOMPANY THE SYSTEM AND PRECIPITATION.

ANOTHER COLD FRONT IS EXPECTED TO PRODUCE SIMILAR CONDITIONS TUESDAY
INTO WEDNESDAY. HOWEVER...MODEL GUIDANCE FOR THIS ONE OFFERS
PRECIPITATION IN A MORE SCATTERED DISTRIBUTION. AS SUCH...THE
MAGNITUDE OF SUB-VFR CONDITIONS MAY BE LESS.

&&

.EQUIPMENT...
AS OF 730 AM EDT FRIDAY ...

THE VISIBILITY SENSOR AT KDAN...DANVILLE REGIONAL AIRPORT...WILL
BE OUT OF SERVICE UNTIL FURTHER NOTICE. A PART HAS BEEN BACK-ORDERED.

&&

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

&&

$$
SYNOPSIS...AMS
NEAR TERM...AMS/WP
SHORT TERM...RCS
LONG TERM...PC
AVIATION...AMS/JH
EQUIPMENT...AMS



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