Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 240542
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
142 AM EDT FRI APR 24 2015

.SYNOPSIS...
HIGH PRESSURE ENTERS THE OHIO VALLEY THIS EVENING ALLOWING WINDS
TO WEAKEN OVERNIGHT...WITH FREEZING TEMPERATURES EXPECTED FOR THE
MOUNTAINS BY FRIDAY MORNING. LOW PRESSURE WILL TRACK FROM THE
SOUTHERN AND CENTRAL PLAINS EAST TO OVER THE REGION BY SATURDAY
MAKING FOR A WET WEEKEND.

&&

.NEAR TERM /THROUGH TODAY/...
AS OF 300 PM EDT THURSDAY...

HIGH PRESSURE IN THE MID WEST AND A TROUGH ALONG THE MID ATLANTIC
COAST CREATED A TIGHT PRESSURE GRADIENT OVER THE AREA TODAY. THIS
PRESSURE GRADIENT CREATED WINDY AND GUSTY CONDITIONS OVER THE
REGION. HIGH PRESSURE TRACKS TO THE SOUTHERN OHIO VALLEY THIS
EVENING...ALLOWING WINDS TO CALM DOWN SOME OVERNIGHT. A SUBSIDENCE
INVERSION DEVELOPS AND LOWERS ACROSS THE AREA OVERNIGHT...KEEPING
THE STRONGER WINDS ALOFT. SURFACE WINDS WILL NOT COMPLETELY DECOUPLE
AND RADIATIONAL COOLING CONDITIONS ARE NOT IDEAL TO PRODUCE
WIDESPREAD FROST EAST OF THE BLUE RIDGE...DESPITE TEMPERATURES
DROPPING INTO THE LOWER TO MID 30S. ALSO...SINCE AFTERNOON DEW
POINTS ARE DOWN IN THE 10F-20F RANGE...ENOUGH MOISTURE TO FORM
PATCHY FROST IS HIGHLY UNLIKELY. WITH THIS IN MIND...NO FROST
ADVISORY WILL BE POSTED FOR COUNTIES EAST OF THE BLUE RIDGE.

TEMPERATURES ACROSS THE MOUNTAINS ARE EXPECTED TO DROP BELOW
FREEZING...UPPER 20S TO LOWER 30S. AGAIN...LACK OF MOISTURE AND
MIXING WILL DETER FROST FROM FORMING...HOWEVER FREEZING TEMPERATURES
CAN HURT SENSITIVE VEGETATION. IT IS ADVISED TO PROTECT SENSITIVE
VEGETATION BY MOVING IT TO A SHELTERED AREA IF POSSIBLE...OR PERHAPS
BY PLACING A PROTECTIVE COVER OVER THE VEGETATION. SUBSIDENCE
INVERSION SHOULD BREAK BY 9AM ALLOWING WINDS TO INCREASE TO 10-20
MPH. ALSO BY 9AM...TEMPERATURES WILL HAVE WARMED ABOVE FREEZING.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
AS OF 300 PM EDT THURSDAY...

EXPECT TO SEE INCREASING CLOUDS SWINGING ACROSS THE AREA FRIDAY
NIGHT AHEAD OF A WARM FRONT STRETCHING FROM MO/KS ESE INTO THE
SOUTHERN APPALACHIANS. SFC HIGH WILL BE MOVING FROM THE ERN GREAT
LAKES SOUTH TO OFF THE SC COAST FRIDAY EVENING...TO PA TO SE NC BY
SAT MORNING. MAY START TO SEE SOME LIGHT RAIN MOVING INTO THE MTNS
AFTER MIDNIGHT WITH GREATER PUSH INTO THE AREA SATURDAY MORNING.
BEST LIFT ARRIVES IN THE MORNING WITH A SECONDARY MAXIMUM OF LIFT
SHIFTING INTO THE MTNS SAT EVENING.

WILL SEE LIKELY TO CATEGORICAL POPS SATURDAY WITH OFF AND ON RAIN.
INSTABILITY WILL STAY LIMITED SOUTHWEST OF US BUT COULD PUSH INTO
THE MTNS OF WV/FAR SW VA AND NW NC TOWARD THE AFTERNOON...SO ADDED
SCT THUNDER PER DAY 3 SPC OUTLOOK.

THIS LOW WILL BE GAINING STRENGTH AS IT SHIFTS EAST TO THE OHIO
VALLEY SATURDAY EVENING...THEN MAINTAINING ITSELF AS IT HEADS OVER
AND EAST OF OUR AREA SAT NIGHT/EARLY SUNDAY. WILL SEE SOME DRY
SLOTTING AS THIS LOW EDGES IN WITH MAIN BULK OF RAIN AFFECTING THE
NRN CWA SAT NIGHT...THOUGH CANNOT RULE OUT ANYWHERE STAYING
COMPLETELY DRY.

THE MODELS ARE HANDLING THIS SOMEWHAT SIMILAR IN TAKING A SECONDARY
SFC LOW ACROSS THE CAROLINAS SUNDAY AS ANOTHER SHORTWAVE SWINGS
BY...AND THINK SUNDAY WILL STAY ON THE DAMP SIDE...BUT SATURDAY
LOOKS WETTER AT THIS POINT. BY SUNDAY NIGHT...AXIS OF TROUGH SHIFTS
EAST AS WE GET A NORTHERLY FLOW FEEDING DRIER AIR IN.

WITH UPPER TROUGH AND RAIN TEMPS THIS PERIOD SHOULD STAY BELOW
NORMAL...ESPECIALLY DURING THE DAY SATURDAY...WITH HIGHS RANGING
FROM THE UPPER 40S HIGHLANDS...TO LOWER TO MID 50S SOUTH...AND
POSSIBLY AROUND 60 SW VA OUTSIDE THE MODEST WEDGE...WITH POSSIBLE
BREAKS IN THE OVC.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 230 PM EDT THURSDAY...

MODELS MAKING A SHIFT TO OUR SOUTH WITH THE NEXT WEATHER MAKE FOR
MID WEEK. STILL WILL NOT COMPLETELY GO DRY AS THIS IS ONE RUN...AND
WILL HAVE TO WAIT AS THE PACIFIC ENERGY PUSHES THE SYSTEM ONSHORE
OUT WEST TO SEE IF THIS SETS UP FURTHER SOUTH THAN PREVIOUSLY
FORECASTED. SPLIT FLOW WILL ALSO KEEP CONFIDENCE IN FORECAST BEYOND
THE SHORT TERM LOW. WILL ALLOW FOR DRY WEATHER MONDAY INTO TUESDAY
WITH INCREASING CLOUDS TUESDAY THEN CHANCE OF RAIN TUESDAY NIGHT
THROUGH THURSDAY. STILL OVERALL LOOKING COOLER THAN NORMAL THROUGH
THE EXTENDED.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 130 AM EDT FRIDAY...

SURFACE HIGH PRESSURE CONTINUES TO BUILD IN FROM THE WEST THROUGH
THE REMAINDER OF THE NIGHT...WITH VERY DRY AIR ASSOCIATED WITH
THE AIRMASS SUPPORTING VFR CONDITIONS. THE PRESSURE GRADIENT
THROUGH THE NIGHT WILL REMAIN TIGHT ENOUGH TO SUPPORT GUSTY
RIDGETOP WINDS...HOWEVER SUSTAINED WINDS AT TAF SITES WILL BE
10KTS OR LESS...WITH OCCASIONAL GUSTS IN THE 15KT TO 20KT RANGE
FOR KROA/KBCB/KBLF/KLWB.

THE HIGH PRESSURE CENTER DOES NOT PASS DIRECTLY OVER THE AREA...
THEREFORE ONCE THE INVERSION BREAKS FRIDAY MORNING (AROUND
14Z)...THE WINDS WILL INCREASE TO 10-15KTS WITH A FEW GUSTS IN THE
18-22KT RANGE. DRY AIR ASSOCIATED WITH THE HIGH WILL ALLOW FOR
CONTINUED VFR CONDITIONS THROUGH THE END OF THE 24/06Z TAF
PERIOD...ALTHOUGH HIGH CLOUDS WILL BE ON THE INCREASE BY SUNSET.

HIGH CONFIDENCE IN VFR CIGS/VSBYS THROUGH THE TAF VALID PERIOD.
MEDIUM TO HIGH CONFIDENCE IN WIND SPEED/DIRECTION THROUGH THE TAF
VALID PERIOD.

EXTENDED AVIATION DISCUSSION...

BY SATURDAY...MOISTURE APPEARS DEEP ENOUGH TO ALLOW FOR PERIODS
OF RAIN AND MVFR...WITH BEST FORCING ACROSS THE CAROLINAS. COMPLEX
LOW PRESSURE TO THE WEST WILL THEN PUSH THROUGH THE REGION
SATURDAY NIGHT INTO SUNDAY...BEFORE EXITING OFFSHORE SUNDAY NIGHT.
THIS WILL LIKELY KEEP SUB-VFR CONDITIONS IN LOW CLOUDS AND
LINGERING RAINFALL INTO SUNDAY NIGHT. FLYING CONDITIONS SHOULD
START TO IMPROVE SOME BY MONDAY AS THE LOW PULLS FARTHER OFFSHORE
AND WEAK HIGH PRESSURE BUILDS IN FROM THE NORTHWEST. HOWEVER
CONTINUED CYCLONIC FLOW LIKELY TO KEEP MORE MVFR CIGS OVER THE
MOUNTAINS WITH IMPROVEMENT TO VFR ACROSS THE EAST ON MONDAY.

&&

.EQUIPMENT...
AS OF 330 PM EDT THURSDAY...

SEVERAL EQUIPMENT ISSUES TO REPORT. THE WYTHEVILLE NOAA WEATHER
RADIO BROADCAST WILL BE UNAVAILABLE INTO FRIDAY. A TECHNICIAN WILL
BE OUT THERE TOMORROW TO WORK ON IT.

THE DEWPOINT AT RICHLANDS VA IN TAZEWELL COUNTY VIRGINIA IS
REPORTING ERRONEOUS DEWPOINTS...SO IGNORE.

THE TEMPERATURES AND DEWPOINTS REPORTED FROM THE VIRGINIA TECH
AIRPORT WILL BE INTERMITTENT. THE FAA HAS BEEN NOTIFIED ABOUT THIS
PROBLEM.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR VAZ007-009>020-
     022>024.
NC...FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR NCZ001-002-018.
WV...FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR WVZ042>044-507-
     508.

&&

$$
SYNOPSIS...NF/WP
NEAR TERM...RCS
SHORT TERM...WP
LONG TERM...WP
AVIATION...NF/PM
EQUIPMENT...


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