-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 251134
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
734 AM EDT SAT MAY 25 2013

.SYNOPSIS...
HIGH PRESSURE WILL CONTROL OUR WEATHER HEADING INTO THE WEEKEND.
EARLY NEXT WEEK A WARM FRONT LIFTS NORTH ACROSS US...REACHING THE
GREAT LAKES BY MIDWEEK. THIS WILL BRING A RETURN OF TEMPERATURES
AND WEATHER MORE TYPICAL OF SUMMER.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 400 AM EDT SATURDAY...

HIGH PRESSURE CONTINUES TO BUILD INTO THE REGION THIS MORNING.
SURFACE OBSERVATIONS INDICATE LIGHT WINDS EVERYWHERE EXCEPT THE
HIGHER RIDGES WHICH ARE ABOVE THE NIGHTTIME INVERSION...WHERE
STILL SEEING GUSTS IN THE 20 TO 25 MPH RANGE. OTHERWISE...LOOKING
AT CLEAR SKIES. STILL HAVE A FREEZE WARNING IN EFFECT FOR SEVERAL
OF OUR MOUNTAIN COUNTIES...HOWEVER IT APPEARS THAT FREEZING
TEMPERATURES WILL BE LOCALIZED AND CONFINED TO DEEPER VALLEYS
ACROSS THE WARNING AREA...AND THAT MOST LOCATIONS WILL REMAIN
ABOVE FREEZING. WITH PLENTY OF DRY AIR IN PLACE...TEMPERATURES
WILL SPIKE UPWARD QUICKLY AFTER SUNRISE.

WILL START THE DAY OFF WITH CLEAR SKIES...HOWEVER THIN HIGH CLOUDS
WILL BUILD IN FROM THE WEST DURING THE AFTERNOON AND EVENING.
WINDS WILL NOT BE AS STRONG TODAY COMPARED TO THOSE OF FRIDAY AS
THE PRESSURE GRADIENT IS FAR MORE RELAXED...BUT WE CAN STILL
EXPECT OCCASIONAL GUSTS TO 20 MPH FOR LATE MORNING AND THE
AFTERNOON...MORE SO ACROSS THE MOUNTAINS. WIND SPEEDS WILL
DIMINISH QUICKLY BY SUNSET. HIGHS FOR TODAY WILL BE A LITTLE
WARMER AS WELL...BUT STILL UNSEASONABLY COOL...WITH AFTERNOON
TEMPERATURES REACHING INTO THE LOW TO MID 60S ACROSS THE
MOUNTAINS...AND INTO THE LOW 70S ACROSS THE PIEDMONTS.

FOR SATURDAY NIGHT...THE ALLEGHANY HIGHLANDS AND PORTIONS OF
SOUTHEAST WEST VIRGINIA WILL EXPERIENCE MOSTLY CLEAR SKIES AND
LIGHT WINDS...WHILE THICKER CLOUD COVER WILL BE CONFINED FURTHER
SOUTH. WITH TEMPERATURES BOTTOMING OUT IN THE MID 30S TOWARD
SUNRISE SUNDAY MORNING ACROSS OUR NORTHWEST COUNTIES...BELIEVE
THERE IS A CHANCE OF PATCHY FROST ACROSS BATH...GREENBRIER AND
MONROE COUNTIES...ALTHOUGH LOCALIZED FROST MAY ALSO DEVELOP
ELSEWHERE ACROSS THE MOUNTAINS NORTH OF INTERSTATE 81.
OTHERWISE...EXPECT TO REMAIN PRECIPITATION FREE THROUGH THE NIGHT.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 530 AM EDT SATURDAY...

THIS PERIOD WILL BE THE TRANSITION PERIOD FROM THE DEEP UPPER
LOW AND ASSOCIATED UNSEASONABLY COLD TEMPERATURES ACROSS THE
MID-ATLANTIC REGION TO A BONAFIDE SUMMERLIKE SUBTROPICAL RIDGE
BUILDING IN FROM THE CENTRAL U.S. BY MID-WEEK. 850MB TEMPS WILL
RISE FROM NEAR 0C EARLY SUNDAY ACROSS THE NE PART OF THE CWA TO
NEAR +20C IN THE SW PART OF THE CWA BY MID-WEEK. PREVIOUS RUNS OF
THE MODELS HAD BEEN ADVERTISING GOOD POTENTIAL FOR RIDGE RIDER...
MCS ACTIVITY AS THE BAROCLINIC ZONE LIFTED NORTH ACROSS THE REGION
MON-TUE WITH STRONG MID-LEVEL WAA ON THE BACK SIDE OF THE
DEPARTING UPPER LOW. HOWEVER...RECENT RUNS OF THE MODELS HAVE
BACKED OFF CONSIDERABLY ON THIS POTENTIAL. THERE IS STILL SOME
THREAT FOR AN MCS TO DEVELOP ACROSS IL/IN/OH/KY AREA LATE MON AND
MOVE SE THROUGH THE NW FLOW ALOFT. THE BEST TRACK FOR THIS...IF IT
OCCURS...APPEARS TO BE TOWARD FAR SW VA/E TN/NW NC. THE SFC AIR
MASS AT THIS POINT ACROSS THE RNK CWA REMAINS VERY DRY...SO IT IS
NO LIKELY THAT ANY SUCH MCS HAS A GREAT CHANCE OF SURVIVING VERY
FAR EASTWARD INTO THE CWA. BY TUE-WED...THE UPPER RIDGE CONTINUES
TO BUILD ACROSS THE REGION AND SHUNT ANY POTENTIAL FOR MCS
ACTIVITY MUCH FURTHER NORTH ACROSS OH/PA/NY...WHICH WOULD THEN
MOVE EAST AND NOT SOUTHEAST INTO THE UPPER HIGH. HOWEVER...AS A
BERMUDA SFC HIGH SETS UP WITH CONSIDERABLE INCREASE IN DEWPOINTS
AND MOISTURE INTO THE REGION FROM THE ATLANTIC...EXPECT A MARKED
INCREASE IN DIURNAL/AFTERNOON SHRA/TSRA ACTIVITY INDUCED BY
DIFFERENTIAL HEATING ALONG THE ALLEGHANYS ESPECIALLY. WITH ALL OF
THIS IN MIND...HAVE TAILORED POPS TO REFLECT SLIGHT CHC FOR
MCS/BAROCLINIC ZONE ACTIVITY LATE MON/EARLY TUE FROM SOUTH TO
NORTH...THEN TRENDED TOWARD ALMOST ENTIRELY DIURNAL MOUNTAIN
FOCUSED ACTIVITY TUE AFTERNOON AND WED AFTERNOON. AT THIS
POINT...TUE AFTERNOON APPEARS TO BRING THE BEST THREAT FOR
SHRA/TSRA ACTIVITY...AS BY WED...UPPER RIDGE ASSOCIATED SUBSIDENCE
WILL TEND TO SUPPRESS ACTIVITY SOMEWHAT. TEMPERATURES WILL WARM
NOTICEABLY THROUGH THE PERIOD...BEGINNING BELOW NORMAL SUN TO EVEN
ABOVE NORMAL BY WED. HAVE USED A ECMWF/GFS MOS MODEL
BLEND...ESPECIALLY DURING THE LATER PERIODS.

&&

.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 100 PM EDT FRIDAY...

THE UPPER TROUGH OFF THE NEW ENGLAND COAST WILL MOVE EAST ENOUGH TO
ALLOW FOR THE START OF RIDGING OVER THE AREA. HOWEVER...THE NORTHERN
EXTENT OF THE RIDGE WILL BE DAMPENED FLAT AND ZONAL ACROSS THE
REGION THANKS TO A SHORTWAVE TROUGH HEADING SOUTHEAST THROUGH THE
OHIO VALLEY. WE WILL START TO TREND MILDER...BUT SHOWERS AND STORMS
WILL BE IN THE FORECAST THANKS TO THE SHORTWAVE TROUGH FEATURE THROUGH
TUESDAY.

WEDNESDAY THROUGH FRIDAY THE UPPER RIDGE STRENGTHENS AND
TEMPERATURES CONTINUE THEIR UPWARD TREND. BY FRIDAY...HIGHS IN THE
UPPER 80S TO AROUND 90 WILL BE COMMON EAST OF THE BLUE RIDGE...WITH
LOW TO MID 80S IN THE MOUNTAINS. THE HIGHEST PEAKS WILL BE IN THE
UPPER 70S.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
AS OF 730 AM EDT SATURDAY...

VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE TAF VALID PERIOD.
OTHER THAN SOME PASSING CI...MAINLY ACROSS THE SW HALF OF THE
FORECAST AREA...SKC SHOULD PREVAIL FOR THE MOST PART. NO FOG NOTED
AT ANY OF THE RNK TAF SITES THIS MORNING...ALTHOUGH JUST ON THE
OTHER SIDE OF THE ALLEGHANYS...NEAR 0SM VSBY IN FOG FOR MANY WV
SITES. FEEL THIS WILL STAY ON THAT SIDE OF THE MOUNTAINS THIS
MORNING. WILL NEED TO WATCH THIS MORE CAREFULLY SUN MORNING GIVEN
SLOWLY INCREASING MOISTURE AND NEAR 0F T/TD SPREAD EARLY SUN AT
LWB. OTHERWISE...VFR VSBYS EXPECTED THROUGH TAF VALID PERIOD.
WINDS WILL BE GUSTY AGAIN TODAY...BUT NOT QUITE AS STRONG AS
FRI...AS A TIGHT GRADIENT REMAINS IN PLACE BETWEEN THE DEPARTING
LOW TO THE NE AND THE SFC HIGH SPREADING INTO THE OH VALLEY. AFT
14Z...EXPECT WNW-NW WINDS 12-15KTS WITH GUSTS 20-25KTS AT MOST TAF
SITES...SLIGHTLY LESS FOR LWB. WINDS WILL DIMINISH VERY QUICKLY
AFTER SUNSET AND SHOULD BECOME CALM AT LWB/BCB/LYH/DAN SHORTLY
THEREAFTER.

HIGH CONFIDENCE IN VFR CIGS THROUGH TAF VALID PERIOD.
HIGH CONFIDENCE IN VFR VSBYS THROUGH TAF VALID PERIOD...EXPECT
MEDIUM CONFIDENCE LWB AFT 06Z SUN.
HIGH CONFIDENCE IN WIND SPD/DIR THROUGH TAF VALID PERIOD.

EXTENDED AVIATION DISCUSSION...MOISTURE INCREASES AGAIN NEXT
WEEK AS THE SFC HIGH MOVES EAST AND THE UPPER RIDGE STRENGTHENS
OVER THE MISSISSIPPI VALLEY. WILL BE GETTING TO MORE HUMID WEATHER
AGAIN WITH SCT THUNDERSTORM THREAT BY TUESDAY AND FOG ISSUES AT
NIGHT IN THE VALLEYS AND ESPECIALLY IN ANY AREAS THAT RECEIVE
RAINFALL LATE THE DAY BEFORE.
-- End Changed Discussion --

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...FREEZE WARNING UNTIL 8 AM EDT THIS MORNING FOR VAZ007-018>020.
     FROST ADVISORY FROM 2 AM TO 8 AM EDT SUNDAY FOR VAZ020.
NC...NONE.
WV...FREEZE WARNING UNTIL 8 AM EDT THIS MORNING FOR WVZ042>045.
     FROST ADVISORY FROM 2 AM TO 8 AM EDT SUNDAY FOR WVZ044-045.

&&

$$
SYNOPSIS...NF
NEAR TERM...NF
SHORT TERM...RAB
LONG TERM...DS
AVIATION...NF/RAB