Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 041958
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
358 PM EDT MON MAY 4 2015

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN CENTERED OVER THE COAST OF THE CAROLINAS
THROUGH MOST OF THIS WEEK. A BACK DOOR COLD FRONT WILL HEAD SOUTH
INTO THE REGION BY WEDNESDAY. AN AREA OF LOW PRESSURE IS EXPECTED TO
FORM OFF THE COAST OF FLORIDA BY THE MIDDLE OF THE WEEK...AND THEN
LATE THIS WEEK INTO THE WEEKEND...TRACK ONSHORE THROUGH THE
CAROLINAS.

&&

.NEAR TERM /THROUGH TUESDAY/...
AS OF 300 PM EDT MONDAY...

HIGH PRESSURE REMAINS SITUATED OFF THE COAST OF THE CAROLINAS. FLOW
AROUND ASSOCIATED RIDGE AXIS IS BRINGING WEAK ONSHORE FLOW IS
WESTWARD THROUGH THE GA/GC. THE FLOW THEN VEERS SOUTHWEST WITH THE
ATLANTIC MOISTURE REACHING THE SOUTHWEST PORTION OF THE FORECAST
AREA. THIS MOISTURE ALONG WITH DIFFERENTIAL HEATING AND OROGRAPHICAL
INFLUENCE IS HELPING TO GENERATE SOME ISOLATED SHOWERS ALONG THE
CREST OF THE BLUE RIDGE FROM ROUGHLY FLOYD VIRGINIA...SOUTHWEST INTO
THE NORTHERN MOUNTAINS OF NORTH CAROLINA. THIS TREND WILL CONTINUE
THE REMAINDER OF THE AFTERNOON...WITH THE ACTIVITY QUICKLY
DISSIPATING WITH THE APPROACH AND ARRIVAL OF SUNSET.

TONIGHT...THE CLOUD COVER ASSOCIATED WITH THE AFTERNOON CONVECTION
WILL LIKEWISE NOT SURVIVE TOO LONG INTO THE OVERNIGHT HOURS.
ANTICIPATE MOST AREAS TO BE MOSTLY CLEAR TO CLEAR BY MIDNIGHT. WITH
INCREASING SOUTHWESTERLY FLOW...ANTICIPATE HIGHER DEW POINT AIR TO
ADVECT INTO THE REGION TONIGHT AS COMPARED TO CONDITIONS REALIZED
THIS MORNING. LIKEWISE...THE FORECAST LOW TEMPERATURES WILL BE
MILDER THAN THOSE OF LAST NIGHT. A MIX OF LOW TO MID 50S ARE
EXPECTED ACROSS THE MOUNTAINS WITH MID TO UPPER 50S ACROSS THE
PIEDMONT.

ON TUESDAY...BOTH TEMPERATURES AND LOW LEVEL MOISTURE CONTENT WILL
BE GREATER THAN WHAT WAS EXPERIENCED TODAY. WE ARE EXPECTING ANOTHER
DAY OF AFTERNOON SHOWER DEVELOPMENT WITH INCREASED COVER THAN WHAT
WE ARE EXPERIENCING TODAY. COVERAGE IS EXPECTED TO BE SCATTERED
ACROSS THE MOUNTAINS...WITH ISOLATED THUNDERSTORMS A GREATER
POTENTIAL THAN TODAY. COVERAGE WILL BE ISOLATED JUST EAST OF THE
CREST OF THE RIDGE...EAST TO A LINE FROM ROUGHLY LYNCHBURG VA TO
YADKINVILLE NC. HIGH TEMPERATURES WILL BE A LITTLE WARMER THAN THOSE
OF TODAY. EXPECT MID 70S TO NEAR 80 ACROSS THE MOUNTAINS WITH LOW TO
MID 80S ACROSS THE PIEDMONT.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 330 PM EDT MONDAY...

SIMILAR TO PREVIOUS NIGHTS...SHOWER ACTIVITY AND CLOUD COVER WILL
DIMINISH TUESDAY EVENING WITH THE LOSS OF DAYTIME HEATING...MAKING
FOR MOSTLY CLEAR SKIES AFTER MIDNIGHT. MAY SEE A FEW POCKETS OF FOG
DEVELOP...MAINLY ACROSS AREAS WHERE SIGNIFICANT RAINFALL OCCURRED ON
TUESDAY AFTERNOON/EVENING. OVERNIGHT LOWS WILL FALL INTO THE LOW TO
MID 50S.

RAINFALL COVERAGE WILL BE MORE WIDESPREAD ON WEDNESDAY AS HIGH
PRESSURE MOVES ACROSS THE GREAT LAKES...PUSHING A COLD FRONT
SOUTHWARD ACROSS THE MID ATLANTIC. EXACT TIMING OF THE FRONTAL
PASSAGE THROUGH OUR AREA IS STILL IN QUESTION...BUT LATEST MODEL
GUIDANCE SUGGESTS THAT THE FRONT WILL PASS THROUGH DURING THE
AFTERNOON AND EVENING. CONVERGENCE AHEAD OF THE FRONT WILL OFFER
ENOUGH SUPPORT FOR SCATTERED SHOWERS...WITH A FEW THUNDERSTORMS
DURING LATE AFTERNOON INTO THE EVENING. A FEW STORMS MAY BECOME
STRONG...BUT BELIEVE SEVERE THUNDERSTORM ACTIVITY WILL BE ISOLATED
AT BEST. DEEPER MOISTURE WILL POOL AHEAD OF THE FRONT HOWEVER...
PUSHING PRECIPITABLE WATER VALUES TO 1.1 INCHES MOUNTAINS TO 1.4
INCHES PIEDMONT. AND WITH LIGHT STEERING WINDS EXPECTED...BELIEVE A
FEW SHOWERS/STORMS WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAIN.
EXPECT HIGHS TO RANGE FROM THE MID/UPPER 70S FOR THE MOUNTAINS...TO
THE MID 80S ACROSS THE SOUTHSIDE.

HIGH PRESSURE WILL BUILD INTO THE AREA WEDNESDAY NIGHT WITH THE
PASSAGE OF THE COLD FRONT...TURNING WINDS ACROSS OUR AREA EASTERLY
FOR THURSDAY. MUCH OF THE TIME...THE HIGH PRESSURE WEDGE AND
EASTERLY WINDSHIFT WOULD RESULT IN SIGNIFICANTLY COOLER TEMPERATURES
FOR THE MID ATLANTIC. HOWEVER...UPPER LEVEL RIDGING ACROSS THE EAST
WILL COUNTERACT THE EASTERLY FLOW...SHAVING OFF ONLY A FEW DEGREES
FOR THURSDAY AFTERNOON HIGHS COMPARED TO WEDNESDAY. HIGH PRESSURE
WILL PROVIDE MORE STABILITY HOWEVER...AND EXPECT ONLY SPOTTY SHOWER
ACTIVITY...WITH PERHAPS ONE OR TWO THUNDERSTORMS DURING THE EVENING.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 345 PM EDT MONDAY...

MODELS ARE COMING INTO BETTER AGREEMENT THAT A TROPICAL LOW RIDING
NORTH FROM THE CARIBBEAN WILL MOVE ONSHORE SOMEWHERE ALONG THE SOUTH
CAROLINA COAST THURSDAY EVENING. THE MAIN IMPACT FOR OUR AREA WOULD
BE AN INCREASE OF DEEPER MOISTURE HEADING THROUGH THE WEEKEND...
WHICH WOULD IN TURN SUPPORT LOCALLY HEAVY RAIN IN SOME OF THE
SHOWERS AND THUNDERSTORMS THAT DEVELOP EACH AFTERNOON AND EVENING
WITH DAYTIME HEATING. UPPER LEVEL WINDS WILL REMAIN LIGHT THROUGH
THE WEEKEND...INDICATING THAT ANY SHOWERS AND THUNDERSTORMS WILL BE
SLOW MOVING. AFTERNOON HIGHS WILL RANGE FROM THE MID 70S WEST TO THE
LOW 80S EAST EACH DAY...WHILE OVERNIGHT LOWS WILL BE IN THE UPPER
50S TO LOW 60S.

&&

.AVIATION /20Z MONDAY THROUGH SATURDAY/...
AS OF 200 PM EDT MONDAY

VFR CIGS EXPECTED THROUGH THE TAF VALID PERIOD.

SATELLITE IMAGERY INDICATES CU FIELD ACROSS MUCH OF THE FORECAST
AREA HAVING DEVELOPED WITH DAYTIME HEATING...MORE PRONOUNCED
ACROSS THE MOUNTAINS. CEILING BASES REMAIN IN THE 5KFT TO 10KFT
RANGE THIS AFTERNOON...WITHIN A LAYER OF PERSISTENT MID-LEVEL.
A FEW CU HAVE MANAGED TO BREAK THROUGH THE MID LEVEL INVERSION
ALONG THE BLUE RIDGE SOUTH OF KROA...AND HAVE FORMED INTO SHOWERS.
WITH LIGHT WINDS AREAWIDE...SHOWER MOVEMENT WILL BE SLOW. EXPECT
LOCALIZED REDUCTIONS IN VISIBILITY INSIDE THE RAIN SHAFTS. EXPECT
THESE CONDITIONS TO PERSIST THROUGH AROUND SUNSET...WHEN THE LOSS
OF DAYTIME HEATING WILL CAUSE THE CU FIELD TO DISSIPATE.

MOSTLY CLEAR SKIES ARE EXPECTED FOR THE OVERNIGHT...WITH LOCALIZED
FOG DEVELOPMENT...PARTICULARLY IN THOSE FEW SPOTS WHERE
SIGNIFICANT RAINFALL OCCURS.

SIMILAR TO MONDAY...CU FIELD WILL REDEVELOP DURING LATE MORNING
ON TUESDAY...WITH A FEW SHOWERS DEVELOPING TOWARD THE END OF THE
TAF PERIOD.

MEDIUM TO HIGH CONFIDENCE IN CLOUD BASES THROUGH THE TAF VALID
PERIOD. HIGH CONFIDENCE IN VISIBILITIES. MEDIUM CONFIDENCE IN
WIND DIRECTION AND SPEED THROUGH THE TAF VALID PERIOD.

NOTE...THE VISIBILITY SENSOR AT THE ASOS AT KBLF CONTINUES TO BE
SPORADICALLY OUT OF SERVICE. REPAIRS MAY NOT BE POSSIBLE UNTIL THE
END OF MAY. WILL CONTINUE WITH AMD NOT SKED APPENDED TO BLF TAF.

EXTENDED AVIATION DISCUSSION...

SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO PERSIST ALONG
THE SOUTHERN BLUE RIDGE INTO TUESDAY EVENING...PRODUCING LOCALIZED
MVFR/IFR CONDITIONS WITHIN THE RAIN SHAFTS.

SHOWERS AND THUNDERSTORMS WILL BE MORE NUMEROUS ON WEDNESDAY AND
THURSDAY AS A BACK DOOR FRONT ENTERS THE REGION FROM THE NORTHEAST.

EXTENDED PERIODS OF SUB-VFR CIGS/VSBYS APPEAR UNLIKELY THIS WEEK...BUT
MORNING FOG WILL BECOME AN INCREASING ISSUE THROUGHOUT THE WEEK AT
THE USUAL SPOTS...KLYH/KDAN/KBCB/KLWB. WINDS OVERALL WILL BE ON
THE LIGHT SIDE THROUGH THE WEEK.

&&

.EQUIPMENT...
AS OF 200 AM EDT MONDAY...

THE VISIBILITY SENSOR AT THE BLUEFIELD...KBLF ASOS...IS
EXPERIENCING INTERMITTENT OUTAGES.

&&

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

&&

$$
SYNOPSIS...DS
NEAR TERM...DS
SHORT TERM...NF
LONG TERM...NF
AVIATION...DS
EQUIPMENT...PM



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