National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 162301
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
701 PM EDT SUN JUN 16 2013

.SYNOPSIS...
A COLD FRONT WILL MOVE SOUTH THROUGH THE REGION INTO MONDAY BRINGING
PERIODS OF SHOWERS AND THUNDERSTORMS TO THE AREA. THE FRONT WILL
STALL SOUTH OF THE REGION MONDAY NIGHT AWAITING YET ANOTHER COLD
FRONT TUESDAY. A WIDESPREAD SOAKING RAIN AND SCATTERED
THUNDERSTORMS ARE EXPECTED TUESDAY INTO WEDNESDAY BEFORE WEAK HIGH
PRESSURE BUILDS ACROSS THE AREA THURSDAY.

&&

.NEAR TERM /THROUGH MONDAY/...
-- Changed Discussion --
AS OF 658 PM EDT SUNDAY...

WIDESPREAD SHOWERS...WITH ISOLATED TO SCATTERED THUNDER AND SOME
WITH VERY HEAVY RAINFALL...CONTINUE TO MOVE INTO THE WESTERN
PORTION OF THE AREA AHEAD OF A WEAK UPPER LEVEL WAVE OVER CENTRAL
KY AT THIS TIME. WITH INSTABILITY BEGINNING TO SLOWLY
DIMINISH...ANY SEVERE THREAT IS VERY SMALL TO JUST ABOUT
GONE...AND BY 8PM SHOULD BE NON-EXISTENT. HOWEVER THE COVERAGE OF
SHOWERS WITH TEH SHORT WAVE MAY INCREASE IN THE WEST...AND WITH
SOME UPSLOPE HELPING TO ANCHOR NEW DEVELOPMENT IN A FEW
SPOTS...BIGGER CONCERN IS LOCALIZED HEAVY RAINFALL THROUGH AT
LEAST MIDNIGHT...WITH AN ISOLATED FLASH FLOOD THREAT IN THE WEST.
MOST HIGH RES MODELS STILL SUGGEST THE BULK OF CONVECTIVE ACTIVITY
WILL SHIFT MORE INTO SOUTHER PART OF THE AREA BY MIDNIGHT..AND
THEN DIMINISH MORE RAPIDLY. A FEW SHOWERS OR ISOLATED STORMS MAY
MAKE IT EAST OF THE BLUE RIDGE...MAINLY NORTH OF US 460 THIS
EVENING...AND POSSIBLY INTO PIEDMONT OF NC LATE TONIGHT...BUT
SHOULD BE MAINLY SHOWERS BY THEN.

MADE SLIGHT ADJUSTMENTS TO POPS TO MATCH CURRENT
COVERAGE...INCLUDING MENTION OF HEAVY RAINFALL IN FAR WEST...AND
REDUCED THUNDER TO CHANCE OR SLIGHT CHANCE REST OF THE NIGHT...BUT
WITH LIKELY TO CAGETORICAL POPS FAR WEST FOR A FEW MORE HOURS THIS
EVENING.

PREV DISCUSSION AS OF 340 PM EDT SUNDAY...

HIGH PRESSURE LOCATED IN THE WESTERN ATLANTIC THIS AFTERNOON
RESULTING IN SOUTHERLY FLOW TRANSPORTING MOISTURE BACK INTO THE MID
ATLANTIC REGION FOR THIS FATHERS DAY. DEW POINTS IN THE 60S HAVE
PUSH NORTH TO THE MASON-DIXON LINE THIS AFTERNOON. DESPITE THE CLOUD
COVER TEMPERATURES HAVE CLIMBED INTO THE MID 80S ACROSS SOUTHERN
PORTIONS OF CWA. THE COMBINATION OF A WEAK CAP ABOUT 700MB...AND
THUNDERSTORM DEBRIS CLOUDINESS HINDERING THUNDERSTORM DEVELOPMENT.
A COUPLE OF MID LEVEL SHORTWAVES TRACK EAST ACROSS THE REGION OVERNIGHT
INTO MONDAY. MEANWHILE SFC COLD FRONT DROPS SOUTHWARD ACROSS THE REGION
DURING THE PERIOD AS WAVES OF LOW PRESSURE ROLL EAST ALONG THE BOUNDARY.
SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP AHEAD AND ALONG THE
FRONT THIS AFTERNOON INTO MONDAY. AN ISOLATED STRONG TO SEVERE
MAY BE POSSIBLE ESPECIALLY ACROSS THE NORTH WITH BETTER DYNAMICS WITH
MAIN THREAT BEING DAMAGING WINDS. THE 12Z RNK WRFARW HAS THE GREATEST
COVERAGE OF CONVECTION THIS AFTERNOON ACROSS THE WESTERN MOUNTAINS THEN
SHIFT ACTIVITY EAST TONIGHT. THE GFS INDICATED SCATTERED CONVECTION
SPREADING EAST ACROSS THE REGION...THEN WORKS IN SOME DRIER AIR LATE
TONIGHT AND EARLY MONDAY. THE NAM WAS SIMILAR WITH CONVECTION THEN
PUNCH IN DRIER AIR ALONG THE EASTERN SLOPES OF THE BLUE RIDGE. HARD TO
TELL HOW MUCH DRIER AIR WORKS IN BEHIND THE SHORTWAVE OVERNIGHT...BUT
ELECTED TO TRIM POPS A LITTLE ACROSS THE NORTH. WITH CLOUD COVER AND
PRECIPITATION PLAYED LOW TEMPERATURES OVERNIGHT CLOSER TO WARMER ADJMAV
VALUES FROM THE UPPER 50S IN THE NORTHWEST MOUNTAINS TO NEAR 70 DEGREES
IN THE PIEDMONT. BLENDED THE ECMWF AND ADJMAVBC FOR HIGH TEMPERATURES ON
MONDAY RESULTING IN READINGS FROM THE MID 70S IN THE MOUNTAINS TO
THE MID 80S IN THE SOUTHEAST.
-- End Changed Discussion --

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS OF 255 PM EDT SUNDAY...

WILL FOLLOW CLOSER TO THE 00Z ECMWF AS IT HAS LESS CONVECTIVE
FEEDBACK AND TOO STRONG A VORT CENTERS...ALTHOUGH CANNOT RULE OUT
SOME CLUSTERS OF CONVECTION TO OUR WEST. GOING INTO MONDAY NIGHT A
SHORTWAVE PUSHES FROM MIDDLE KY/TN ESE INTO OUR REGION BY 12Z
TUESDAY. THIS IS ACTUALLY WITH A PREFRONTAL SFC TROUGH AND MAIN LIFT
GOES BY TO THE SOUTH WITH NEXT VORT INDUCED WAVE ARRIVING INTO THE
WEST BY MID MORNING TUESDAY. MONDAY NIGHT KEPT HIGHER POPS ACROSS
THE SOUTHWEST WHERE BETTER LOW LVL CONVERGENCE OCCURS. WILL STILL
BLEND IN OTHER MODELS TUESDAY GIVEN UNCERTAINTY ON FRONTAL
PASSAGE...BUT WE LOOK TO AT LAST SEE LIKELY POPS CWA WIDE...ALTHOUGH
THE 12Z ECMWF NOW COMING IN HAS PUSHED EVEN FURTHER SOUTH THE DEEPER
MOISTURE AND FRONT WHERE HEAVIEST RAIN WILL FALL FROM TN INTO NC.

SVR THREAT SEEMS MARGINAL GIVEN HOW MUCH CLOUD COVER IS
EXPECTED...LEADING TO POOR LOW LVL LAPSE RATES...AND DYNAMICS ALOFT
APPEAR LACKING.

TRICKY FORECAST WILL CONTINUE TUE NIGHT-WED AS IT DEALS WITH HOW FAR
SOUTH THE FRONT GOES AND WHERE THE BEST PRECIP CHANCES LIE. WILL
TRANSITION MORE TO STRATIFORM TUE NIGHT/EARLY WED GIVEN FRONT TO THE
SOUTH AND OVERRUNNING. WILL GO WITH LOWER POPS FOR NOW BUT IF THE
MODELS BECOME CONSISTENT ON A FURTHER NORTH LOCATION OF THE FRONT
COULD SEE HIGHER POPS TUE NIGHT-WED. FOR WHAT ITS WORTH THIS PERIOD
LOOKS MORE CLOUDY AND DAMP. WENT WITH HIGHS COOLER THAN MOS THINKING
THE PRECIP WILL HOLD TEMPS DOWN. WITH SFC HIGH MOVING NORTH OF US
WEDNESDAY...AND WIND FROM THE NE SHOULD KEEP US COOL.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 1245 PM EDT SUNDAY...

MODELS THIS PERIOD KEEPING A BROAD TROUGH INTO THE EAST BUT EDGING
EAST BY FRIDAY AS HIGH PRESSURE EXPANDS FROM TEXAS TO JUST WEST OF
US. SFC HIGH PRESSURE STAYS JUST NORTHEAST OF US AND KEEPS OUR
REGION IN THE LIGHT EAST TO SOUTH FLOW AS A FRONTAL BOUNDARY STALLS
AND WEAKENS SOUTH OF US MIDWEEK. THIS WILL SET UP A PATTERN OF
INVERTED TROUGHINESS ACROSS THE MTNS THRU FRIDAY WHERE BEST THREAT
OF SHOWERS EXISTS AND PERHAPS SOME THUNDERSTORMS AS WELL. NO CLEAR
DEFINITIVE SHORTWAVE BUT WILL SEE SOME WEAK ONES HELP TRIGGER
CONVECTION. AT THIS TIME KEPT POPS LOW CHANCE IN THE WEST TO SLIGHT
CHANCE ACROSS THE MIDDLE OF THE CWA/BLUE RIDGE AND LITTLE TO NONE IN
THE EAST. TEMPS WARM BACK ABOVE NORMAL BY THE WEEKEND AS THE UPPER
RIDGE BUILDS NORTHEAST...AND STILL SEEING POTENTIAL FOR CONVECTION
PUSHING SOUTHEAST INTO THE AREA DURING THIS TIME BUT OVERALL FLOW
KEEPS MOST NORTH OF US ALONG A FRONT DRAPED FROM THE MIDWEST INTO
THE GREAT LAKES. SO ASIDE FROM MAINLY DIURNAL CONVECTION IT SHOULD
BE DRY.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 205 PM EDT SATURDAY...

MVFR SHOWERS AND THUNDERSTORMS WILL DEVELOP AND INCREASE IN
COVERAGE IN THE WEST THIS AFTERNOON AND SPREAD SOUTHEAST TOWARD
DAN IN THE 00Z-02Z TIME FRAME. LWB IS THE TAF SITE WITH BEST
CHANCE FOR A THUNDERSTORM THIS AFTERNOON INTO TONIGHT. HOWEVER
THERE IS THE POTENTIAL FOR THUNDERSTORMS AT THE OTHER TAF
LOCATIONS LATE THIS AFTERNOON INTO TONIGHT.

MID-LEVEL CLOUDS AND GROUND FOG FROM MOIST GROUND WILL BE THE
CONCERN AFTER 06Z...WITH MVFR CIGS ADVERTISED FOR BLF/LWB.
OTHERWISE...CIGS EXPECTED TO BE MID/HIGH VARIETY THROUGH THE
DAYTIME WITH SCT VFR CU. INTRODUCED MVFR CIGS BCB/BLF/LWB WITH
TSRA ACTIVITY.

MVFR SCT-BKN CLOUDS WITH PATCHY FOG MAY LINGER AT BCB/LWB
OVERNIGHT INTO MONDAY MORNING WITH MOIST GROUND AND NEAR CALM
WINDS AND LITTLE AIR MASS CHANGE. SOUTHWEST WINDS AROUND 10-12KTS
WITH GUSTS TO 25KT THIS AFTERNOON DECREASE THIS EVENING INTO
TONIGHT...EXCEPT IN/NEAR THUNDERSTORM ACTIVITY.

MEDIUM TO HIGH CONFIDENCE IN CIGS THROUGH TAF VALID PERIOD.
MEDIUM TO HIGH CONFIDENCE IN VSBYS THROUGH TAF VALID PERIOD.
HIGH CONFIDENCE IN WIND SPD/DIR THROUGH TAF VALID PERIOD.

EXTENDED AVIATION DISCUSSION...ANY BREAK FROM THE INCLEMENT
CONDITIONS WILL BE BRIEF...WITH MORE MVFR SHRA/TSRA LIKELY
MONDAY THROUGH TUESDAY AS WAVES OF LOW PRESSURE RIDE ALONG A
STALLED FRONTAL BOUNDARY SOUTH OF THE CWA.

BLF ASOS REMAINS UNAVAILABLE BECAUSE OF A POWER OUTAGE. WILL
CONTINUE AMD NOT SKED...BUT CONDITIONS LATER TODAY MAY WARRANT A
NIL TAF FOR BLF.

&&

.EQUIPMENT...
-- Changed Discussion --
ASOS OBSERVATION FROM BLUEFIELD (BLF) APPEARS TO BE AVAILABLE ONCE
AGAIN...HOWEVER DUE TO A NWS GATEWAY COMMUNICATIONS ISSUE THAT IS
NEW THIS EVENING...MOST NWS OFFICES ARE NOT INGESTING CURRENT ASOS
AND AWOS OBSERVATIONS AT THE MOMENT...NOR ARE WE INGESTING ANY
LIGHTNINF DATA. A BACK LOG MAY START TO FLOW SHORTLY AS THE
PROBLEM IS BEING WORKED AT THE NATIONAL LEVEL.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...KK/RAB
NEAR TERM...KK/SK
SHORT TERM...WP
LONG TERM...WP
AVIATION...KK/RAB
EQUIPMENT...RAB/SK