000
FXUS61 KRNK 130346
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1146 PM EDT SUN MAY 12 2013

.SYNOPSIS...
HIGH PRESSURE WILL PROGRESS FROM THE MISSISSIPPI RIVER VALLEY TO
THE APPALACHIANS BY TUESDAY MORNING. WEDNESDAY INTO THURSDAY...THE
HIGH WILL SHIFT TO OFF THE ATLANTIC COAST...AND A WARM FRONT WILL
HEAD NORTH THROUGH THE TENNESSEE AND OHIO VALLEYS. A COLD FRONT
WILL APPROACH THE REGION ON FRIDAY...AND STALL NEAR THE MASON-
DIXON LINE OVER THE WEEKEND.

&&

.NEAR TERM /THROUGH MONDAY/...
AS OF 1140 PM EDT SUNDAY...

FREEZE/FROST HEADLINES TO REMAIN AS IS...ALTHOUGH THREAT OF FROST
WILL BE MARGINAL GIVEN THE SPREAD IN TEMPS VS DEWPOINTS. LATEST
NAM/CMC CONTINUE TO ADVERTISE SOME CLOUDINESS MAKING IT INTO THE
MOUNTAINS BEFORE DAWN...AND THIS MAY THROW A WRENCH INTO ANY FROST
FORMING AND ONLY A FEW AREAS GETTING TO FREEZING...WHICH MOST
FOLKS WITH SENSITIVE VEGETATION ARE HOPING FOR. TEMPERATURES IN
SOME AREAS THOUGH HAVE ALREADY DROPPED INTO THE MID TO UPPER 30S
OVER THE MOUNTAINS.

WINDS REMAIN UP AT ELEVATIONS ABOVE 2000 FEET. THIS WILL ALSO PLAY
A ROLE INTO HOW MUCH IF ANY FROST/FREEZE TAKES PLACE.


PREVIOUS VALID DISCUSSION...
WENT WITH FORECAST LOW TEMPERATURES A FEW DEGREES BELOW EITHER
THE MAV OR MET MOS GUIDANCE GIVEN THE DEW POINT TREND...FROM THE
UPPER 20S TO THE MID 30S IN THE MOUNTAINS...WITH MID 30S TO AROUND
40 IN THE PIEDMONT.

ON MONDAY...THE NOCTURNAL INVERSION WILL BREAK FAIRLY QUICKLY...SO
WE EXPECT A FAST WARM-UP ABOVE FREEZING BY MID-MORNING. DURING THE
DAY...WE EXPECT A GRADUAL INCREASE IN CLOUD COVER ASSOCIATED WITH A
WEAK SHORTWAVE TROUGH THAT WILL BE PROGRESSING THROUGH THE OHIO
VALLEY. GUIDANCE IS HINTING THAT SOME AFTERNOON SHOWERS MAY GRAZE
THE NORTHERN THIRD OF THE AREA. WILL HOLD OFF FOR NOW ON ANY MENTION
OF THIS.

ON MONDAY...HIGHS WILL RANGE FROM THE 50S IN THE MOUNTAINS...TO
LOWER 60S EAST OF THE BLUE RIDGE.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS OF 315 PM EDT SUNDAY...

SURFACE HIGH PRESSURE WILL BE CENTERED OVER THE FORECAST AREA BY
12Z/8AM TUESDAY. WHILE NOT MUCH CHANGE IN AIR MASS...CONDITIONS WILL
BE MORE FAVORABLE FOR RADIATIONAL COOLING...ESPECIALLY IN THE
VALLEYS. HAVE KEPT MINIMUM TEMPERATURES JUST BELOW GUIDANCE AND HAVE
MAINTAINED FROST FOR A LARGE SECTIONS OF THE FORECAST AREA. WILL
HIGHLIGHT THIS THREAT IN THE HAZARDOUS WEATHER OUTLOOK.

WARM FRONT CROSSES THROUGH THE OHIO VALLEY TUESDAY NIGHT AND
WEDNESDAY MORNING WITH SOME DECENT ISENTROPIC LIFT. ENOUGH
MOISTURE...LIFT AND WARM AIR ADVECTION FOR TO INCLUDE A SMALL
PROBABILITY OF PRECIPITATION IN THE NORTHERN COUNTY WARNING AREA.

BY LATE WEDNESDAY MUCH WARMER AIR MASS WILL COVER THE REGION. 850 MB
TEMPERATURES RECOVER INTO THE +14 TO +18 RANGE. CLOUDS IN THE
MORNING ON MAY LIMIT THE AMOUNT OF HEATING FOR THE DAY BUT HIGHS
WILL STILL BE MUCH WARMER THAN TUESDAY.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 110 PM EDT SUNDAY...

ZONAL PATTERN ALOFT AND BROAD SOUTHWEST TO WEST SURFACE AND LOW
LEVEL WINDS WILL KEEP STATIONARY FROM PENNSYLVANIA TO MISSOURI
THROUGH THIS PART OF THE FORECAST PERIOD. WITH THE MAIN FOCUS FOR
PRECIPITATION TO THE NORTH OF THE FORECAST AREA...NOT MUCH TO
TRIGGER SHOWERS AND THUNDERSTORMS.

MODELS STILL BRING SHORT WAVE COMING THROUGH THE SOUTHERN STREAM
INTO THE REGION ON FRIDAY. HAVE THIS DAY WITH A SLIGHTLY HIGHER
PROBABILITY OF PRECIPITATION. OTHERWISE JUST EXPECT TYPICAL
OROGRAPHICALLY INDUCED AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS.

TEMPERATURES WILL BE NEAR NORMAL TO ABOVE NORMAL THROUGH THE PERIOD.
NO REASON TO STRAY FAR FROM CURRENT GUIDANCE.

&&

.AVIATION /04Z MONDAY THROUGH FRIDAY/...
AS OF 728 PM EDT SUNDAY...

AFTER SUNSET...THE SURFACE GUSTS WILL END WITH NORTHWEST WINDS
SUSTAINED STILL AROUND 4 TO 8 KTS ACROSS THE MOUNTAINS...WITH CALM
OR LIGHT NORTHWEST WINDS EAST OF THE CREST OF THE BLUE RIDGE.
PATCHY FROST WILL BE POSSIBLE TONIGHT IN SOME OF THE
HIGHER...SHELTERED VALLEYS. ANY CLOUDS GENERATED BY HEATING WILL
DISSIPATE RAPIDLY TONIGHT.

VFR CONDITIONS WILL CONTINUE MONDAY MORNING...AND NORTHWEST
SURFACE GUSTS WILL RETURN TO AROUND THE 20 KT RANGE.

HIGH PRESSURE WILL HELP MAINTAIN MAINLY VFR CONDITIONS THROUGH AT
LEAST WEDNESDAY.

THE NEXT CHANCE FOR SHOWERS AND STORMS AND WIDESPREAD SUB VFR
CONDITIONS IS NOT EXPECTED UNTIL THE END OF THE
WEEK...THURSDAY/FRIDAY TIME FRAME AS FIRST A WARM FRONT LIFTS
THROUGH THE REGION...AND THEN A COLD FRONT APPROACHES FROM THE
WEST.

&&

.CLIMATE...
LOW TEMPERATURES MONDAY AND TUESDAY MORNING WILL FLIRT WITH RECORD
LOW TEMPERATURES AT ALL CLIMATE LOCATIONS WITH THE BEST CHANCE FOR
BREAKING ANY RECORDS BEING TUESDAY MORNING. THE FOLLOWING ARE THE
CURRENT RECORD LOW TEMPERATURES FOR MAY 13 AND MAY 14 ALONG WITH
THE YEAR OF THAT RECORD.

MAY 13                MAY 14
ROA...35...1917       ROA...37...1996
LYH...35...1969       LYH...33...1997
RNK...26...1969       RNK...31...1996
DAN...38...1960       DAN...38...2007
BLF...33...1996       BLF...33...1996

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...FROST ADVISORY UNTIL 9 AM EDT MONDAY FOR VAZ007-009-010-
     012>015-018-023-024.
     FREEZE WARNING UNTIL 9 AM EDT MONDAY FOR VAZ011-019-020.
NC...FROST ADVISORY UNTIL 9 AM EDT MONDAY FOR NCZ001-002.
     FREEZE WARNING UNTIL 9 AM EDT MONDAY FOR NCZ018.
WV...FREEZE WARNING UNTIL 9 AM EDT MONDAY FOR WVZ042>045.

&&

$$
SYNOPSIS...
NEAR TERM...DS/WP
SHORT TERM...AMS
LONG TERM...AMS
AVIATION...DS/KM
CLIMATE...CF