Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 270750 AAA
AFDRNK

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BLACKSBURG VA
350 AM EDT SAT JUN 27 2015

.SYNOPSIS...
A WARM FRONT WILL LIFT NORTH OF THE AREA BY THIS AFTERNOON AHEAD
OF A DEEP LOW PRESSURE SYSTEM THAT WILL SLIDE UP THE OHIO RIVER
VALLEY BY LATE IN THE DAY. THIS WILL BRING ADDITIONAL ROUNDS OF
SHOWERS AND STORMS TO THE REGION INTO THIS EVENING. A STRONG COLD
FRONT WILL MOVE ACROSS THE AREA TONIGHT...RESULTING IN GUSTY
NORTHWEST WINDS AND UNSEASONABLY COOL TEMPERATURES.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 240 AM EDT SATURDAY...

SWATH OF HEAVIER SHRA/TSRA JUST NORTH OF THE SURFACE WARM FRONT
AND ALONG THE LOW LEVEL THETA-E GRADIENT CONTINUES TO WORK OFF TO
THE NE AND SHOULD EXIT THE FAR NORTHERN COUNTIES AROUND SUNRISE.
THIS WILL BRING A BRIEF LULL IN CONVECTION EARLY THIS MORNING AS
THE WARM FRONT STARTS TO LIFT NORTH AHEAD OF THE UPSTREAM COLD
FRONT THAT WONT MAKE IT INTO THE MOUNTAINS UNTIL EARLY THIS
EVENING. THUS WILL GRADUALLY TRIM BACK POPS TO MOSTLY CHANCE TO
START THE MORNING PER THE LATEST HRRR BEFORE HEATING COMMENCES
AND STARTS TO RECHARGE THINGS AHEAD OF THE BOUNDARY THIS
AFTERNOON. LATEST GUIDANCE REMAINS CONSISTENT IN BRINGING ADDED
BANDS OF DEEPER CONVECTION INTO THE WEST BY AFTERNOON BEFORE
THINGS LIKELY CONSOLIDATE HEADING OFF THE BLUE RIDGE TOWARD MID
AFTERNOON IF NOT SOONER. HOWEVER BEST SUPPORT INCLUDING WINDS
ALOFT WILL PASS TO THE NORTH WITH OVERALL BEST SHEAR ENDING UP
ALONG THE WARM FRONT OVER NORTHERN VA. ALSO SIMILAR TO
FRIDAY...WILL INIT WITH LITTLE INSTABILITY PER HEAVY RAIN FROM
OVERNIGHT WHICH LOOKS TO LEAD TO SOMEWHAT WEAKER LAPSES/CAPES THIS
AFTERNOON AS SEEN VIA THE LATEST NAM SHOWING ONLY 1K J/KG VALUES
WEST AND PERHAPS 2K OUT EAST PENDING THE DEGREE OF HEATING BEFORE
THINGS REDEVELOP. THIS SUPPORTS THE BEST SEVERE THREAT OUT EAST
FOR MAINLY DAMAGING WINDS PER HEAVY PRECIP LOADING AS SEEING
LITTLE DRY AIR ALOFT OFF FORECAST SOUNDINGS.

OTRW SPEED OF BANDS/CLUSTERS SHOULD BE A BIT FASTER GIVEN THE
30-40 KT SW JET ALOFT. HOWEVER SINCE ALREADY HAVE A FLASH FLOOD
WATCH IN PLACE WILL CLIP OFF A FEW COUNTIES ACROSS THE SOUTH WHERE
RAINFALL HAS BEEN LESS AND ADD A COUPLE ALONG THE BLUE RIDGE UP
NORTH. ALSO PLAN TO EXTEND THE WATCH OUT UNTIL 6 PM TO COVER
HEAVY RAIN WITH THE FRONT AND MATCH UP WITH BORDERING OFFICES FOR
NOW. THEREFORE KEPT LIKELY/CAT POPS THIS AFTERNOON WITH ONLY A
SLOW EXODUS OF HEAVIER SHRA TO THE EAST AROUND 00Z WITH CHANCES
LINGERING WEST UNTIL FROPA THIS EVENING. HIGH TEMPS A BIT COOLER
GIVEN CLOUDS AROUND WITH MOSTLY 70S TO NEAR 80 WEST AND LOW/MID
80S EAST PROVIDED SOME SUN.

COLD FRONT PUNCHES TO THE EAST OVERNIGHT ALLOWING A GOOD DRY SLOT
TO WORK EAST AIDED BY 40 KTS AT 85H AND STRONG COOL ADVECTION
UNDER THE PASSING UPPER TROUGH. THIS SHOULD BRING AN END TO MOST
SHOWERS AFTER MIDNIGHT WITH ONLY SOME RESIDUAL UPSLOPE FLOW LIGHT
SHOWERS POSSIBLE NW THROUGH DAYBREAK. WINDS LOOK GUSTY GIVEN THE
ABRUPT 85H COOLING BUT BELOW ADVISORY LEVELS PER ONLY WEAK
SUBSIDENCE. TEMPS WILL CRASH BACK INTO THE 50S OVER THE WEST WHERE
WILL GET SOME CLEARING OUTSIDE OF THE UPSLOPE COUNTIES...WHILE
EXPECT LOWS CLOSER TO 60-65 OUT EAST WHERE THE 85H FRONT WONT
CROSS UNTIL LATE.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 315 AM EDT SATURDAY...

GUSTY NW WINDS TO CONTINUE INTO SUNDAY UNDER A LINGERING GRADIENT
BETWEEN THE UPPER LOW PASSING ACROSS NEW ENGLAND AND WEAK HIGH
PRESSURE BUILDING IN FROM THE WEST. SHOULD AGAIN SEE SOME GUSTS TO
40-45 MPH MOUNTAINS MAINLY EARLY BEFORE SPEEDS DIMINISH SOME IN
THE AFTERNOON. DOWNSLOPE DRYING AND SUBSIDENCE SHOULD LEAD TO
CLEARING SKIES IN ALL BUT THE UPSLOPE AREAS WHERE WILL NEED TO
KEEP A LOW END POP FOR ISOLATED SHOWERS NW INTO SUNDAY EVENING
BEFORE THINGS DRY OUT.

TEMPERATURES WILL CONTINUE TO TREND COOLER INTO SUNDAY. HIGHS ON
SUNDAY WILL RANGE FROM AROUND 70 TO THE LOWER 70S ACROSS THE
MOUNTAINS TO THE UPPER 70S TO AROUND 80 ACROSS THE PIEDMONT.

DRY AND COOL HIGH PRESSURE WILL SETTLE OVER THE REGION ON SUNDAY
NIGHT. EXPECT NO PRECIPITATION WITH BELOW NORMAL TEMPERATURES. LOWS
WILL RANGE FROM THE LOW TO MID 50S ACROSS THE MOUNTAINS AND
PERHAPS A FEW 40S DEEPER VALLEYS...WITH UPPER 50S ACROSS THE
PIEDMONT. WHILE NO RECORD LOW TEMPERATURES ARE FORECAST...A FEW
LOCATIONS WILL FALL TO READINGS WITHIN FIVE DEGREES OF RECORD
LOWS. SEE THE CLIMATE SECTION OF THIS DISCUSSION FOR DETAILS.

ON MONDAY...THE CENTER OF THE SURFACE HIGH PRESSURE WILL PROGRESS
EASTWARD IN ADVANCE OF OUR NEXT GREAT LAKES SHORTWAVE TROUGH. EXPECT
A RETURN OF A SOUTHERLY COMPONENT OF THE LOW LEVEL WINDS AND
INCREASING DEW POINTS AND TEMPERATURES. WHILE NO PRECIPITATION IS
FORECAST FOR THE MORNING...SOME ISOLATED SHOWERS MAY DEVELOP ACROSS
THE FAR SW DURING THE AFTERNOON. HIGH TEMPERATURES WILL AVERAGE 5
TO 7 DEGREES MILDER THAN THOSE OF SUNDAY. ANTICIPATE UPPER 70S TO
AROUND 80 IN THE MOUNTAINS AND LOW TO MID 80S ACROSS THE PIEDMONT.

ON MONDAY NIGHT...THE TROUGH AXIS OF THE GREAT LAKES SYSTEM WILL
START PROGRESSING THROUGH THE OHIO VALLEY. LOOK FOR SHOWERS AND
STORMS TO EXPAND IN COVERAGE ACROSS THE WESTERN PARTS OF THE AREA.
STILL LITTLE OR NO COVERAGE IS ANTICIPATED FOR AREAS EAST OF THE
CREST OF THE BLUE RIDGE. LOW TEMPERATURES WILL RANGE FROM THE UPPER
50S TO AROUND 60 ACROSS THE MOUNTAINS TO THE LOWER 60S ACROSS THE
PIEDMONT.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 320 PM EDT FRIDAY...

THIS PORTION OF THE FORECAST PERIOD IS EXPECTED TO BE ONE WITH
SCATTERED SHOWERS AND STORMS ACROSS THE AREA EACH DAY AND NIGHT. THE
AXIS OF A SHORTWAVE TROUGH WILL MOVE THROUGH THE REGION BY MIDDAY
TUESDAY. THE COLD FRONT ASSOCIATED WITH THIS SYSTEM IS EXPECTED TO
STALL OVER...OR JUST SOUTH OF THE AREA...AND TAKE ON A NW-SE
ORIENTATION. THROUGH FRIDAY...LITTLE MOVEMENT OF THIS FRONT IS
EXPECTED. THE COMBINATION OF DAYTIME HEATING...AND THE POTENTIAL FOR
ADDITIONAL WAVES OF ENERGY MOVING SOUTHEAST ALONG THIS FEATURE WILL
BE THE SOURCE OF THE FORECAST SCATTERED SHOWERS AND SOME STORMS.
HIGH TEMPERATURES DURING THIS PORTION OF THE FORECAST WILL RANGE
FROM THE UPPER 70S TO AROUND 80 ACROSS THE MOUNTAINS AND MID TO
UPPER 80S ACROSS THE PIEDMONT. LOW TEMPERATURES WILL MAINLY BE IN
THE LOWER 60S ACROSS THE MOUNTAINS AND UPPER 60S ACROSS THE PIEDMONT.

&&

.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
AS OF 1240 AM EDT SATURDAY...

CLUSTERS OF DEEP CONVECTION REMAIN OVER THE REGION TONIGHT ALONG
AND NORTH OF A SLOW MOVING WARM FRONT THAT IS EXPECTED TO LIFT NE
OF THE REGION BY SATURDAY MORNING. THIS WILL CONTINUE TO PRODUCE
GUSTY SHRA/TSRA AT TIMES IN MOST LOCATIONS OVERNIGHT WITH PERIODS
OF MVFR TO IFR CIGS AND VSBYS PENDING EXACTLY WHERE THE HEAVIER
SHOWERS MOVE ACROSS. THUS WILL INIT WITH OVERALL MVFR CONDITIONS
PER CURRENT OBS AND INCLUDE TEMPO GROUPS FOR LOWER VSBYS/CIGS
WHERE APPEARS STRONGER CELLS MAY CROSS THROUGH MORNING. SOUTH
WINDS ALSO GUSTY ACROSS THE WEST IN/NEAR CONVECTION AND ALONG THE
FRONTAL PASSAGE. ELSEWHERE WILL SEE MORE OF AN EASTERLY COMPONENT
THAT WILL SWING MORE TO THE SOUTH EARLY SATURDAY.

PRIMARY CONCERN SATURDAY IS STRONG FRONTAL PASSAGE WHICH IS
FORECAST BY ALL MODELS TO OCCUR DURING THE LATE AFTERNOON AND
EVENING WITH 40-50KT WESTERLY WINDS 3KFT AGL DEVELOPING BEHIND THE
FRONT SATURDAY NIGHT. ANTICIPATING BKN LINE OF SHOWERS/TSTMS TO
ACCOMPANY THE FRONT SATURDAY AFTERNOON...FOLLOWED BY PARTIAL
CLEARING SATURDAY NIGHT WITH GUSTY WESTERLY WINDS. GIVEN
UNCERTAINTY WITH TIMING OF WHEN BANDS MIGHT CROSS WILL LEAVE IN AN
OVERALL VICINITY MENTION SATURDAY AFTERNOON AFTER MORNING SHRA
EXIT FOR NOW.

EXPECT MAINLY VFR CONDITIONS SUNDAY INTO MONDAY...HIGH PRESSURE
SPREADING ACROSS THE FORECAST AREA. NEXT COLD FRONT IS FORECAST TO
ARRIVE WITH POTENTIAL FOR SHOWERS MONDAY EVENING/OVERNIGHT.
TIMING OF SHOWERS WITH THIS FRONT A BIT UNCERTAIN BUT COULD SEE
PERIODS OF MVFR MONDAY NIGHT AND MAINLY ALONG THE WESTERN SLOPES
TUESDAY...OTHERWISE VFR ACROSS THE EAST. ANOTHER DISTURBANCE
SLIDING IN FROM THE NW MAY BRING THE NEXT ROUND OF SUB-VFR
CONDITIONS ESPCLY ACROSS THE MOUNTAINS ON WEDNESDAY.

&&

.CLIMATE...
AS OF 300 PM EDT FRIDAY...

JUNE 29TH RECORD LOWS

BLACKSBURG...42 IN 1974
BLUEFIELD....52 IN 1970
DANVILLE.....54 IN 1968
LEWISBURG....49 IN 1981
LYNCHBURG....51 IN 1970
ROANOKE......44 IN 1919

&&

.EQUIPMENT...
THE NOAA WEATHER RADIO IN LYNCHBURG...BROADCASTING ON A FREQUENCY
OF 162.550 MHZ...IS OPERATING ON THE SECONDARY TRANSMITTER.
TECHNICIANS CONTINUE TO WORK ON THE ISSUE AND HAVE ADVISED THAT
BOTH TRANSMITTERS WONT BE FULLY OPERATIONAL UNTIL AT LEAST SUNDAY.

THE NOAA WEATHER RADIO IN HINTON WV...BROADCASTING ON A FREQUENCY
OF 162.425 MHZ...IS OFF THE AIR DUE TO A TELCO PROBLEM. THIRD
PARTY TECHNICIANS ARE CURRENTLY WORKING ON THE COMMUNICATION
ISSUE.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR VAZ007-009>015-
     018>020-022>024-034-035.
NC...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR NCZ001.
WV...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR WVZ042>044-507-
     508.

&&

$$
SYNOPSIS...JH/NF
NEAR TERM...JH
SHORT TERM...DS/JH
LONG TERM...DS/WP
AVIATION...JH/PM
CLIMATE...
EQUIPMENT...PM


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