Special Weather Statement, NWS Raleigh, NC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
300 PM EDT THU JUN 21 2012

.SYNOPSIS...
UPPER LEVEL HIGH PRESSURE OVER THE REGION WILL SLIDE OFF THE COAST
TONIGHT. A WEAK COLD FRONT WILL APPROACH THE AREA FROM THE NORTHWEST
ON FRIDAY... AND WILL ADVANCE SLOWLY SOUTHEASTWARD THROUGH THE AREA
SATURDAY AND SATURDAY NIGHT... STALLING OVER SOUTHEAST NORTH
CAROLINA SUNDAY BEFORE WEAKENING.

&&

.NEAR TERM /THROUGH FRIDAY/...
AS OF 300 PM THURSDAY...

TONIGHT:
THE MID/UPPER LEVEL HIGH PRESSURE...CURRENTLY CENTERED VA...WILL
PUSH EASTWARD OFFSHORE AND BECOME FLATTENED TONIGHT. AN UPPER LEVEL
LOW...CURRENTLY OVER GA...WILL APPROACH FROM THE AREA AS OUR NEXT
FRONTAL SYSTEM APPROACHES FROM THE WEST. VERY SLOW MOVING SHOWERS
AND THUNDERSTORMS HAVE DEVELOPED ACROSS THE AREA THIS AFTERNOON AND
WILL LIKELY STICK AROUND THROUGH SUNSET. ALTHOUGH CAPE VALUES ARE
AROUND 2000 J/KG WHERE SHOWERS ARE CURRENTLY OCCURRING...THE WIND
FIELDS ARE WEAK AND DEEP CONVECTION IS UNLIKELY. WINDS COULD GET
GUSTY WHERE THUNDERSTORMS ARE OCCURRING. SOME OF THE HIGH RES
CONVECTION ALLOWING MODELS SHOW ISOLATED SHOWERS LINGERING INTO THE
OVERNIGHT HOURS ACROSS EASTERN PORTIONS OF CENTRAL NC.
HOWEVER...CONFIDENCE IS LOW AND HAVE LEFT CHANCES OUT OF THE
FORECAST FOR TONIGHT. OVERNIGHT LOWS EXPECTED TO BE IN THE LOW
70S...WITH MID 70S ACROSS THE EXTREME NE AREAS.

FRIDAY:
THE AFOREMENTIONED UPPER LEVEL LOW/SHORTWAVE WILL CONTINUE TO SLOWLY
APPROACH THE AREA FROM THE SOUTHWEST...AND MOVE THROUGH SC AND NC
BETWEEN 12Z FRIDAY AND 00Z SATURDAY. BOTH THE FORECAST MODELS AND
HIGH RES CAM SHOW THE PRECIP DEVELOPING ALONG THE MOUNTAINS BETWEEN
12Z AND 18Z...AND MOVING THROUGH CENTRAL NC FRIDAY AFTERNOON AND
EVENING AS THE FRONT MOVING IN FROM THE NW REACHES THE AREA. HAVE
CHANCE FOR SHOWERS AND THUNDERSTORMS. EXPECT CONVECTION TO INCREASE
BY EARLY AFTERNOON ACROSS NORTHERN AND WESTERN PORTIONS OF THE AREA
THEN SPREAD EAST AND SOUTH ALONG A PRE-FRONTAL TROUGH. THE ACTUAL
SURFACE COLD FRONT IS EXPECTED TO BECOME DIFFUSE... WITH THE WIND
SHIFT ALONG THE THE ORIGINAL PRE-FRONTAL TROUGH SLOWLY TRANSLATING
EAST-SOUTHEASTWARD ACROSS THE AREA ON FRIDAY EVENING/NIGHT. FORECAST
VALUES OF MLCAPE FRIDAY AFTERNOON ARE IN THE 1200-1600 J/KG
RANGE...HOWEVER SHEAR VALUES CONTINUE TO BE AROUND 10 KTS OR
SO..THUS A FEW ISOLATED STORMS COULD BECOME SEVERE...WITH THE MAIN
THREAT FROM DAMAGING WINDS. EXPECT HIGHS FRIDAY IN THE LOW TO MID
90S.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 230 PM THURSDAY...

FOR FRIDAY NIGHT: THE SURFACE PREFRONTAL TROUGH IS EXPECTED TO
STRETCH THROUGH CENTRAL NC FRIDAY NIGHT... AND EITHER THIS FEATURE
OR AN OUTFLOW BOUNDARY FROM EARLIER CONVECTION TO OUR NW MAY SERVE
AS A FOCUS TO SUSTAIN ISOLATED STORMS IN CENTRAL NC THROUGH THE
EVENING... AS A WEAK MID LEVEL SHORTWAVE TROUGH PASSES OVER THE
AREA. PRECIP WATER VALUES ARE LIKELY TO REMAIN HIGH... APPROACHING
150% OF NORMAL WELL INTO THE NIGHT... WITH PERSISTENT ELEVATED LOW
LEVEL MOISTURE TRANSPORT INTO CENTRAL/ERN NC. THE NAM RETAINS
MARGINAL TO MODERATE INSTABILITY MAINLY S/E OF GSO WITH PROJECTED
OVERNIGHT MLCAPE OF 800-1500 J/KG... AND 0-6 KM SHEAR OF 15-20 KTS
THAT WOULD SEEM TO SUPPORT AT LEAST ISOLATED STORMS ONGOING THROUGH
THE NIGHT. WITH LIGHT SURFACE WINDS AND CONVECTIVE DEBRIS CLOUDS
INHIBITING RADIATIONAL COOLING... EXPECT WARM LOWS AROUND 70 TO THE
LOWER 70S.

FOR SATURDAY/SATURDAY NIGHT: THE MID LEVEL TROUGH AXIS PROGRESSES
SLOWLY EASTWARD SATURDAY... MOVING THROUGH THE NORTHEAST STATES
WHILE STILL EXTENDING THROUGH EASTERN NC. THE MODELS SUGGEST THAT
THE COOL FRONT WILL EFFECTIVELY JUMP INTO THE PREFRONTAL TROUGH OVER
THE EASTERN PORTION OF THE FORECAST AREA AS THE SURFACE HIGH CENTER
CROSSES LAKE ERIE TO WRN PA... BRINGING SLIGHTLY DRIER AND MORE
STABLE AIR INTO THE TRIAD REGION. BUT THE COLUMN ALONG AND SOUTHEAST
OF THE FRONT WILL REMAIN MOIST AND MODERATELY UNSTABLE WITH MLCAPE
OF 1500-2400 J/KG AND IMPROVING DEEP LAYER SHEAR TO 25-30 KTS.
EXPECTED SCATTERED STORMS TO BLOSSOM PARTICULARLY ALONG AND EAST OF
HIGHWAY 1 BY EARLY AFTERNOON... CONTINUING WELL INTO THE EVENING
BEFORE SLIDING TO THE FAR SOUTHERN AND SOUTHEASTERN FORECAST AREA
AND DECREASING IN COVERAGE. FORECAST SOUNDINGS SHOW DRYING AND
STABILIZING AIR ALOFT ACROSS THE AREA SATURDAY NIGHT SO DEEP
CONVECTION SHOULD WANE SATURDAY NIGHT... BUT WEAK LOW LEVEL WINDS
AND POTENTIAL POOLING OF HIGH PW AIR IN THE SOUTHERN CWA MAY RESULT
IN PERSISTENT SLOW-MOVING SHOWERS... AND THESE COULD MAINTAIN
SCATTERED COVERAGE THROUGH THE NIGHT IF THE NAM'S PROMINENT LOW
LEVEL THETA-E RIDGE NOSING INTO SOUTH CENTRAL NC FROM THE SW COMES
TO FRUITION. REGARDLESS WE ARE LIKELY TO SEE CONVECTIVE DEBRIS
CLOUDINESS TRACKING FROM UPSTREAM MCS ACTIVITY OVER THE MIDWEST INTO
OUR REGION. HIGHS 88-92 AND LOWS 67-72.

FOR SUNDAY/SUNDAY NIGHT: THE MID LEVEL VORTEX STEADILY DEEPENS OVER
JAMES BAY WITH STRENGTHENING TROUGHING OVER EASTERN CANADA AND THE
ST LAWRENCE VALLEY / NORTHEAST... WHILE STRONG AND AMPLIFIED RIDGING
BUILDS THROUGH THE PLAINS. THE QUICKLY WEAKENING SURFACE FRONT
SHOULD REMAIN HUNG UP THROUGH CENTRAL NC THROUGH SUNDAY NIGHT... AS
A MID LEVEL PERTURBATION DROPS INTO THE BASE OF THE MEAN TROUGH OVER
EASTERN NOAM. FORECAST SOUNDINGS DEPICT SUFFICIENTLY STABLE/DRY MID
LEVEL AIR OVER CENTRAL NC TO LIMIT DEEP CONVECTION... AND DEPENDING
ON THE TIMING AND DEGREE OF UPSTREAM CONVECTIVE COMPLEXES OVER THE
MIDWEST AND THEIR LIKELY PATH FOLLOWING THE THERMAL WIND TOWARD
NC... A SHIELD OF MID AND HIGH CLOUDS MAY FURTHER CUT DOWN IN THE
POTENTIAL FOR INSTABILITY. BASED ON THE PRESENCE OF THE LINGERING
SURFACE TROUGH AND RESIDUAL LOW LEVEL MOISTURE FOSTERING LOW
LEVEL-ROOTED PARCEL BUOYANCY WITH HEATING... WILL RETAIN A MENTION
OF ISOLATED STORMS MAINLY IN THE SOUTHERN CWA STARTING SUNDAY
AFTERNOON. A SUBSTANTIAL COLD FRONT WILL DROP THROUGH MI TOWARD THE
OHIO VALLEY AS THE LONGWAVE TROUGH DEEPENS... AND THIS MAY SERVE TO
RE-ESTABLISH A LEE TROUGH OVER THE NW PIEDMONT SUNDAY NIGHT. WITH
THE RISK OF MORE ORGANIZED CONVECTION MORE LIKELY TO OCCUR TO OUR
NORTH SUNDAY NIGHT (WHERE DYNAMIC FORCING FOR ASCENT IS BETTER)...
WILL LEAVE IT DRY OVER CENTRAL NC FOR NOW. SEASONABLE HIGHS 87-91.
WARM LOWS IN THE LOW-MID 70S WITH PARTLY CLOUDY SKIES. -GIH

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 235 PM THURSDAY...

THE PRIMARY FEATURES OF NOTE DURING THIS TIME PERIOD WILL BE THE
DEEPENING MID LEVEL VORTEX OVER THE ST LAWRENCE VALLEY... AND THE
FATE OF SURFACE LOW PRESSURE STRENGTHENING OVER THE GULF EARLY IN
THE PERIOD.

REGARDING THE SOUTHEAST CANADA VORTEX AND EASTERN NOAM LONGWAVE
TROUGH... MODELS ARE IN GOOD AGREEMENT ON THE LOW CENTER WOBBLING
OVER SRN ONTARIO AND THE ADJACENT EASTERN GREAT LAKES WITH THE
TROUGH ITSELF AMPLIFYING STEADILY DOWN THE EASTERN SEABOARD. THE
INCOMING COLD FRONT -- THE LEADING EDGE OF A COOL CANADIAN AIR MASS
-- IS POISED TO PUSH SOUTHEAST INTO NC BY TUESDAY... BUT THE DEGREE
OF SOUTHEASTWARD PROGRESSION WILL GREATLY DEPEND ON OUR SECOND
FEATURE OF CONCERN... THE GULF LOW. THE GFS/ECMWF HAVE VARIED WIDELY
IN RECENT RUNS WITH THE TRACK... STRENGTH... AND EVEN SIMPLY THE
PRESENCE OF THE LOW... SO CONFIDENCE IN ITS BEHAVIOR THROUGH THE
BEGINNING AND MIDDLE OF NEXT WEEK IS QUITE LOW. THE LATEST GFS TAKES
THE LOW ACROSS FL SUNDAY NIGHT THEN TRACKS IT NORTHEASTWARD OFF THE
SOUTHEAST COAST BEFORE DRAWING IT NORTHWARD INTO THE LARGER VORTEX
BY WEDNESDAY... AND THIS ALLOWS THE COLD FRONT TO DROP SOUTHEAST
THROUGH CENTRAL NC. IN CONTRAST... THE 00Z ECMWF KEEPS THE LOW OVER
THE CENTRAL AND NORTHEAST GULF THROUGH WEDNESDAY WHILE INTENSIFYING
IT... BEFORE TAKING IT ACROSS NORTHEAST FL... WHICH ALL RESULTS IN
THE COLD FRONT PUSHING INTO NC THEN STALLING OVER THE AREA TUESDAY
THROUGH THURSDAY. GIVEN THE MODEL DISPARITY AND LOW CONFIDENCE IN
THE DETAILS... WILL FAVOR A SOLUTION FEATURING A WEAKER AND LESS
PROMINENT LOW... WITH SCATTERED STORMS MONDAY INTO MONDAY NIGHT
ATTENDING FRONTAL PASSAGE... FOLLOWED BY NO GREATER THAN ISOLATED
AFTERNOON STORMS TUESDAY THROUGH THURSDAY. WITH THE TROUGH DEEPENING
OVER THE EAST AND THICKNESSES LIKELY TO DIP TO NEAR OR BELOW
NORMAL... WILL TREND TEMPS DOWN TO MORE SEASONABLE READINGS... WITH
HIGHS AROUND 90 MONDAY SLIPPING TO THE LOWER-MID 80S TUESDAY THROUGH
THURSDAY. -GIH

&&

 .AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 148 PM THURSDAY...

24-HR TAF PERIOD:
SHOWERS HAVE STARTED TO DEVELOP ACROSS CENTRAL NC. MOST OF THESE
SHOWERS ARE RELATIVELY SHALLOW...HOWEVER A FEW NEAR KRWI HAVE TOPS
NEAR 20 KFT. SO FAR NO LIGHTNING HAS BEEN DETECTED BUT SHOULD A
THUNDERSTORM PASS OVER ANY OF THE TERMINALS...WINDS GUSTING TO 20
KTS OR MORE WITH SUB VFR VISIBILITIES ARE POSSIBLE. FOR NOW HAVE
INCLUDED VCSH AT ALL TERMINALS FOR THIS EVENING...WITH VCTS AT KRWI.
SKIES SHOULD REMAIN SCATTERED TO BROKEN AT ALL TERMINALS WITH BASES
AROUND 5 KFT. OTHERWISE...EXPECT MAINLY VFR CONDITIONS WITH LIGHT
AND VARIABLE WINDS TONIGHT... WITH POSSIBLE BRIEF MVFR CONDITIONS
AROUND SUNRISE WHERE PRECIPITATION HAS OCCURRED. HOWEVER...GIVEN
CONFIDENCE IS NOT HIGH...WILL NOT INCLUDE ANY MENTION IN THE TAFS AT
THIS TIME.

LOOKING AHEAD:
CHANCES FOR CONVECTION WILL INCREASE FRIDAY AFTERNOON INTO FRIDAY
NIGHT AS A FRONTAL ZONE PROGRESSES TOWARD THE CAROLINAS FROM THE
NORTHWEST...HOWEVER...VFR CONDITIONS ARE EXPECTED TO PREVAIL OUTSIDE
OF ANY SHOWERS/STORMS. SOME UNCERTAINTY IN THE FORECAST PERSISTS
THIS WEEKEND THROUGH EARLY NEXT WEEK. AT THIS TIME...VFR CONDITIONS
ARE EXPECTED TO DOMINATE... OUTSIDE OF THE POTENTIAL FOR SOME EARLY
MORNING FOG AND THE POTENTIAL FOR SHOWERS AND STORMS.

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

SYNOPSIS...HARTFIELD
NEAR TERM...KC
SHORT TERM...HARTFIELD
LONG TERM...HARTFIELD
AVIATION...KC/BSD

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>