Severe Thunderstorm Warning 250, NWS Jackson, MS

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON MS
1047 AM CDT FRI JUN 4 2010

.UPDATE...LATEST SATELLITE IMAGERY/SURFACE ANALYSIS SHOWS A STACKED
LOW PRESSURE SYSTEM OVER SOUTHWEST LA...PROGGED BY THE LATEST MODEL
GUIDANCE TO GRADUALLY SHIFT INTO NORTH-CENTRAL LA BY LATE THIS
AFTERNOON. WIDESPREAD SHOWERS AND THUNDERSTORMS ACROSS THE EASTERN
PORTION OF THE LOW HAVE ENCOMPASSED ZONES SOUTH OF INTERSTATE
20...DRIVEN BY ABUNDANT MOISTURE ADVECTION AND LIFT UNDERNEATH 70KT
UPPER LEVEL JET NOSING INTO COASTAL MS. THE CONVECTIVE RISKS WITH
THESE STORMS HAVE NOT CHANGED SINCE THE EARLIER UPDATE AS HEAVY RAIN
AND GUSTY WINDS REMAIN POSSIBLE...AS WELL AS A BRIEF TORNADO ACROSS
FAR SOUTHEASTERN ZONES WHERE GUIDANCE SHOWS AN AXIS OF 125+M^2/S^2
0-1KM HELICITY MOVING ACROSS THE AREA THROUGH THIS AFTERNOON. ENOUGH
INSTABILITY TO PROMOTE VIGOROUS UPDRAFTS IS IN QUESTION DUE TO
ABUNDANT CLOUD COVER IN PLACE...AS WELL AS WARMING FROM THIS
MORNINGS CONVECTION. AS SUCH WILL CONTINUE MENTION OF A BRIEF
TORNADO IN THE HWO...FOCUSING MORE ON THE HEAVY RAIN POTENTIAL. WILL
HOLD OFF ON A FLASH FLOOD WATCH FOR NOW...BUT IF THE SITUATION
DEVELOPS INTO TRAINING SHOWERS AND THUNDERSTORMS...PRIMARILY ACROSS
SOUTHEASTERN ZONES...A FLASH FLOOD WATCH MAY BECOME NECESSARY FOR
THIS EVENING INTO SATURDAY.

CHANGES TO THE FORECAST WERE MINIMAL...JUST TWEAKED THE POPS TO
REFLECT LATEST THINKING AND INCLUDED POSSIBLE GUSTY WINDS ACROSS
SOUTHEASTERN ZONES. AFTERNOON HIGHS LOOKED A LITTLE HIGH AT A COUPLE
SPOTS WITH THE RAIN AND CLOUD COVER EXPECTED. UPDATED PRODUCTS
POSTED...UPDATED AVIATION DISCUSSION BELOW. /BK/

&&

.PREV DISCUSSION... /ISSUED 415 AM CDT FRI JUN 4 2010/

SHORT TERM...TODAY THROUGH SATURDAY NIGHT...SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY AND SATURDAY OVER MUCH
OF THE AREA AS WE REMAIN UNDER THE INFLUENCE OF THE UPPER LEVEL LOW.
WATER VAPOR IMAGERY/RUC ANALYSIS SHOWS THE CIRCULATION AROUND THE
LOW SPINNING OVER THE NORTHEAST TEXAS COAST. A SHORTWAVE ROTATING
AROUND THE EAST SIDE OF THE LOW WAS NOTED MOVING NORTH OVER OUR CWA
AND PRODUCING A BAND OF LIGHT RAIN ALONG THE HIGHWAY 82 CORRIDOR.
THIS BAND OF RAIN IS EXPECTED TO BE JUST NORTH OF OUR CWA BY
DAYBREAK. WEAK SUBSIDENCE AND DRYING NOTED ON WATER VAPOR IMAGERY IN
THE WAKE OF THIS SHORTWAVE SHOULD LIMIT RAIN CHANCES EARLY THIS
MORNING BUT A SWIFT RECOVERY IS PROGGED. THE GFS CONTINUES TO BE
STRONGEST WITH THE NEARLY STACKED LOW BUT MODELS AGREE THAT 850MB
FLOW WILL INCREASE THIS MORNING OVER THE SOUTHEAST HALF OF OUR AREA
AND BRING IN +340K THETAE AIR THAT WILL INCREASE PWS ABOVE TWO
INCHES. THIS WILL COMBINE THE THE LEFT EXIT REGION OF AN UPPER LEVEL
JET STREAK AND DAYTIME HEATING TO BEGIN REDEVELOP OF SHOWERS AND
THUNDERSTORMS THAT SHOULD SPREAD ACROSS MUCH OF OUR AREA. LOCALLY
HEAVY RAIN WILL LIKELY ACCOMPANY ANY STORM BUT A FEW STRONG STORMS
WITH WIND GUSTS TO 30-40MPH WILL ALSO BE POSSIBLE. MODELS SHOW A
DECENT INCREASE IN LOW LEVEL HELICITY OVER OUR SOUTHEAST AS WELL
TODAY WHERE A BRIEF TORNADO CANNOT BE RULED OUT. THE BEST
COMBINATION OF INSTABILITY AND LOW-MID LEVEL WINDS WILL BE LOCATED
PRIMARILY SOUTH OF I-20 AND WL CONTINUE MENTION THIS AREA IN THE
HWO. THE LOSS OF DAYTIME HEATING WILL LEAD TO A NOTED DECREASE IN
CONVECTION THIS EVENING BUT MODELS NOW AGREE THAT THE CLOSED LOW
WILL MOVE SLOWLY TO THE NORTHEAST TODAY AND MOVE OVER OUR SOUTHWEST
ZONES TONIGHT. THIS WILL RESULT IN A CONTINUED CHANCE OF CONVECTION
THROUGH THE NIGHT. MODELS ARE IN FAIR AGREEMENT THAT THE LOW WILL
CONTINUE TO TRACK SLOWLY TO THE NORTHEAST ACROSS OUR CWA SATURDAY
WHILE WEAKENING INTO AN OPEN TROUGH BY SATURDAY EVENING. OUR VERY
MOIST AIRMASS WILL AGAIN DESTABILIZE WITH DAYTIME HEATING RESULT IN
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORM DEVELOPMENT OVER OUR
CWA. AGAIN THE GREATEST COVERAGE IS EXPECTED TO OCCUR OVER THE
SOUTHEAST HALF OF THE CWA. A FEW STRONG STORMS WITH WIND GUSTS TO 40
MPH WILL BE POSSIBLE BUT THE MAIN RISK WILL REMAIN LOCALLY HEAVY
RAINFALL. THE RAINFALL AMOUNTS HAVE BEEN STACKING UP IN OUR SOUTH
LATELY AND AFTER TODAY'S AMOUNTS A FLASH FLOOD WATCH MAY NEED TO BE
CONSIDERED FOR SATURDAY. THE UPPER LEVEL TROUGH AXIS IS EXPECTED TO
SHIFT EAST OF OUR CWA BY SUNDAY MORNING. ALTHOUGH CONVECTION WILL
DECREASE AGAIN SATURDAY EVENING AFTER SUNSET...PRECIPITATION CHANCES
WILL BE TAPERED OFF FROM THE NORTHWEST SATURDAY NIGHT AS THE TROUGH
SHIFTS EAST. GUIDANCE TEMPS WERE CLOSE THROUGH THE SHORT TERM AND
MAV GUIDANCE WAS GENERALLY ACCEPTED. GUIDANCE POPS WERE RAISED IN
THE SOUTH TODAY AND SATURDAY TO CATEGORICAL CHANCES. /22/

LONG TERM...SUNDAY THROUGH NEXT FRIDAY...
BY SUNDAY...THE MID/UPPER-LEVEL LOW WILL HAVE TRANSITIONED TO AN
OPEN WAVE WHILE BECOMING ABSORBED INTO A BROAD DEEP-LAYER TROUGH
OVER THE NORTHEAST CONUS. A MID/UPPER-LEVEL TRAILING TROUGH AXIS
WILL HAVE PUSHED SOUTH OF THE CWA WHILE A RIDGE AXIS EXTENDS
EASTWARD TOWARD THE ARKLAMISS REGION. MODEL CONSENSUS IS FOR A
SURFACE COLD FRONT ASSOCIATED WITH THE NORTHEAST CONUS TROUGH TO
BECOME INCREASINGLY SHALLOW AND DIFFUSE WHILE DRIFTING SOUTHWARD
ACROSS PORTIONS OF THE ARKLAMISS REGION SUNDAY AFTERNOON INTO SUNDAY
NIGHT. THE FRONT IS THEN EXPECTED TO HAVE RETREATED NORTHEAST OF THE
AREA BY MONDAY EVENING. THE OVERALL EVOLUTION OF THE FRONT IS
UNCERTAIN...AS ITS MOTION WILL BE STRONGLY MODULATED BY MESOSCALE
EFFECTS AFTER HAVING OUTRUN ITS LARGE-SCALE SYNOPTIC SUPPORT.
CONVECTION WILL PLAY A SUBSTANTIAL ROLE IN THE EVENTUAL POSITION OF
THE FRONT. FOR PRECIP CHANCES ON SUNDAY...FORECAST FOLLOWS A BLEND
OF THE MEX AND MEN GUIDANCE...WHICH BEST REPRESENTS A MULTI-MODEL
CONSENSUS AND SUGGESTS ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS. THE GREATEST CONVECTIVE COVERAGE ON SUNDAY WILL BE
DURING THE AFTERNOON AND EVENING HOURS AND ACROSS THE NORTHEASTERN
TWO-THIRDS OF THE CWA...WHICH WILL BE CLOSER TO THE THE FRONT. THE
MID-LEVEL HEIGHT GRADIENT ACROSS THE EASTERN PERIPHERY OF THE
AFOREMENTIONED RIDGE WILL SUPPORT NORTHERLY H5 FLOW AT 15 TO
20 KT...WHICH COULD PROMOTE CONVECTIVE ORGANIZATION ON SUNDAY.

MODEL CONSENSUS IS FOR THE FRONT TO GRADUALLY RETREAT NORTHEAST OF
THE CWA THROUGHOUT MUCH OF THE EARLY TO MID WEEK TIME FRAME NEXT
WEEK. THIS WILL OCCUR AS RIDGE OF HIGH PRESSURE BECOMES ESTABLISHED
OVER MUCH OF THE SOUTHERN CONUS AND NORTHERN GULF OF MEXICO. WITH
AMPLE DEEP-LAYER MOISTURE PRESENT...LIMITED CAPPING...AND AMPLE
INSOLATION...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE EACH AFTERNOON AND EVENING. THE GREATER CONVECTIVE COVERAGE
IS EXPECTED ACROSS THE NORTHEAST WHICH WILL BE CLOSER TO THE
FRONT...AND ACROSS THE SOUTHEAST NEAR ANY SEA BREEZE CONVERGENCE ZONES
MOVING NORTHWARD FROM THE GULF COAST. MID/UPPER-LEVEL FLOW WILL HAVE
DECREASED FOR MUCH OF NEXT WEEK AS THE RIDGE AXIS BECOMES POSITIONED
OVER THE ARKLAMISS REGION. THIS WILL REDUCE THE POTENTIAL FOR
CONVECTIVE ORGANIZATION.

NWP MODELS INDICATE THAT A WEAK MID/UPPER-LEVEL LOW WILL SPIN UP
ALONG THE AFOREMENTIONED TRAILING TROUGH AXIS OVER THE COAST OF
NORTHEAST MEXICO LATE SUNDAY. THIS FEATURE WILL THEN BE STEERED
NORTHWARD WITHIN A WEAKNESS IN THE SOUTHERN CONUS RIDGE. MODELS
DISAGREE WITH REGARD TO THE EVENTUAL TRACK OF THIS FEATURE LATER THIS
WEEK. HOWEVER...THE GFS AND ECMWF INDICATE WEAK ASCENT IN THE
SOUTHEASTERN SEMICIRCLE OF THE CYCLONIC CIRCULATION BRUSHING THE
FORECAST AREA FOR THURSDAY INTO FRIDAY. THIS WILL MAINTAIN CHANCES
FOR CONVECTION INTO LATE NEXT WEEK...WITH THE POTENTIAL FOR MORE
ORGANIZED CONVECTION IF THE LOW TRACKS FURTHER TO THE EAST.

WITH REGARD TO THE POTENTIAL FOR STRONG TO SEVERE STORMS THROUGH THE
PERIOD...HIGH TEMPERATURES IN THE LOWER TO MIDDLE 90S COMBINED WITH
AFTERNOON DEWPOINTS IN THE UPPER 60S TO LOWER 70S WILL SUPPORT
SBCAPE VALUES OF 2500-3500 J/KG EACH AFTERNOON. THIS INSTABILITY WILL
RESULT IN ROBUST CONVECTIVE UPDRAFTS. THE WARM BOUNDARY LAYER
TEMPERATURES WILL SUPPORT STEEP LOW-LEVEL LAPSE RATES AND ENHANCE
DCAPE VALUES ALONG WITH THE POTENTIAL FOR WET MICROBURSTS...BUT WILL
LIKELY ENHANCE MELTING OF ANY HAIL STONES. ISOLATED STRONG TO
SEVERE THUNDERSTORMS WILL BE A POSSIBILITY DURING THE AFTERNOON AND
EVENING HOURS THROUGH THE PERIOD. THE GREATEST CHANCE FOR STRONG TO
SEVERE STORMS WILL BE ON SUNDAY WHEN DEEP-LAYER SHEAR WILL BE
SOMEWHAT STRONGER AS MID-LEVEL NORTHERLY FLOW INCREASES. ALSO...WITH
PWAT VALUES OF 1.8 TO 2.0 INCHES...WHICH WILL BE 130 TO 150 PERCENT
OF NORMAL VALUES...LOCALLY HEAVY RAINFALL IS EXPECTED WITH ANY
CONVECTION. MENTION OF THE POTENTIAL FOR STRONG TO SEVERE STORMS AND
HEAVY RAINFALL IS BEING WITHHELD FROM THE HAZARDOUS WEATHER OUTLOOK
AT THIS TIME DUE TO THE LARGE DEGREE OF UNCERTAINTY WITH REGARD TO
THE OVERALL DAILY CONVECTIVE EVOLUTION AND LOCATIONS OF ANY
BOUNDARIES TO FOCUS CONVECTION.

AS FOR FORECAST TEMPERATURES...AFTERNOON H85 TEMPS ARE EXPECTED TO
REACH UP TO 21C RANGE THROUGHOUT THE PERIOD...WHICH COULD SUPPORT
MAXIMUM SURFACE TEMPS OF 96F TO 97F GIVEN FULL MIXING TO H85...AS
SUGGESTED BY MEX GUIDANCE. HOWEVER...AFTERNOON CONVECTION AND
ASSOCIATED CLOUDINESS ARE EXPECTED TO LIMIT INSOLATION AND AMOUNT OF
MIXING...AND THUS FORECAST HIGH TEMPERATURES THROUGH THE PERIOD WERE
TRENDED DOWNWARD FROM MEX GUIDANCE BY A COUPLE DEGREES TOWARD MEN
GUIDANCE...ESPECIALLY WITH THE MEX BEING TOWARD THE UPPER EXTREME OF
ENSEMBLE MOS GUIDANCE. /COHEN/

&&

.AVIATION...AREAS OF IFR STRATUS WERE LIFTING STEADILY ACROSS MAINLY
THE SRN 2/3 OF THE CWFA AT MID MORNING. THE OVERNIGHT BAND OF LIGHT
SHOWERS ALONG THE HIGHWAY 82 CORRIDOR HAS STALLED JUST N OF OUR AREA
WHILE SEVERAL BANDS OF HEAVIER RAINS MOVE IN FROM THE SW. SHRA/TSRA
WILL INCREASE IN COVERAGE AGAIN FROM S TO N THROUGH THE DAY AS THE
CUTOFF VERTICALLY STACKED LOW CENTER IN SWRN LA BEGINS TO OPEN UP
AND GET STRETCHED TOWARD THE ENE. MVFR CLOUD LAYERS SHOULD PREVAIL
MOST AREAS THROUGH TONIGHT WITH POCKETS OF IFR CONDITIONS. AS THE
AIR MASS STABILIZES LATER TONIGHT...ISOLATED SHOWERS AND STORMS WILL
REMAIN POSSIBLE TONIGHT AS A CENTER OF LOW PRESSURE CROSSES SRN MS.
MVFR CEILINGS ARE EXPECTED TO PREVAIL BEFORE 08Z TONIGHT BEFORE
LOWERING TO WIDESPREAD IFR/LIFR THROUGH 14Z SATURDAY. /40/

&&

.PRELIMINARY POINT TEMPS/POPS...
JACKSON       84  71  87  73 /  70  36  63  18
MERIDIAN      85  71  88  71 /  51  49  70  29
VICKSBURG     84  72  89  74 /  85  31  47  16
HATTIESBURG   85  74  88  75 /  86  45  77  29
NATCHEZ       84  71  88  74 /  90  36  62  17
GREENVILLE    87  71  88  74 /  56  20  28   7
GREENWOOD     87  71  87  73 /  37  20  35  16

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&

BK

<!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>

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE JACKSON MS
1248 PM CDT FRI JUN 4 2010

MSZ062>064-072-041830-
MARION MS-LINCOLN MS-LAWRENCE MS-JEFFERSON DAVIS MS-
1248 PM CDT FRI JUN 4 2010

A LINE OF STRONG THUNDERSTORMS CAPABLE OF PRODUCING 40 TO 50 MPH
WINDS WAS LOCATED FROM JAYESS TO 11 MILES SOUTHWEST OF KOKOMO AT 1248
PM CDT...MOVING EAST AT 20 MPH.

VERY HEAVY RAIN ALONG WITH CONTINUOUS CLOUD TO GROUND LIGHTNING ARE
ALSO POSSIBLE WITH THESE STORMS.

PEOPLE IN SOUTHWESTERN JEFFERSON DAVIS...SOUTHERN LAWRENCE...
SOUTHEASTERN LINCOLN AND WESTERN MARION COUNTIES SHOULD MONITOR THESE
STORMS CLOSELY.

JA

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE JACKSON MS
118 PM CDT FRI JUN 4 2010

MSZ026>029-032-033-038-039-046-041915-
KEMPER MS-GRENADA MS-WEBSTER MS-CARROLL MS-MONTGOMERY MS-OKTIBBEHA
MS-CHOCTAW MS-NOXUBEE MS-WINSTON MS-
118 PM CDT FRI JUN 4 2010

...LINE OF STRONG THUNDERSTORMS PUSHING NORTHEAST TOWARD THE GOLDEN
TRIANGLE...

A LINE OF STRONG THUNDERSTORMS CAPABLE OF PRODUCING WINDS TO 45 MPH
AND POSSIBLY SOME PEA SIZE HAIL WAS LOCATED FROM 6 MILES WEST OF
MALMAISON TO DE KALB AT 116 PM CDT...MOVING NORTHEAST AT 20 MPH.

VERY HEAVY RAIN ALONG WITH FREQUENT CLOUD TO GROUND LIGHTNING
STRIKES ARE ALSO POSSIBLE WITH THESE STORMS.

HIGH WINDS CAN BRING DOWN TREES AND LARGE LIMBS RESULTING IN SERIOUS
INJURY OR PROPERTY DAMAGE. EXERCISE EXTREME CAUTION WHEN OUTDOORS
DURING SUCH STRONG WINDS...AND BE ESPECIALLY AWARE OF OLDER TREES.

PEOPLE IN WINSTON...NOXUBEE...CHOCTAW...OKTIBBEHA...MONTGOMERY...
CARROLL...WEBSTER...GRENADA AND KEMPER COUNTIES SHOULD MONITOR THESE
STORMS CLOSELY.

BYB

<!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>

<!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>

<!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>

<!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>