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000
FXUS64 KJAN 131554 AAA
AFDJAN

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON MS
1054 AM CDT THU JUN 13 2013

.UPDATE...WARM AND HUMID CONDITIONS PREVAIL THIS MORNING ACROSS
THE ARKLAMISS. TEMPS THIS AFTERNOON WILL CLIMB INTO THE LOW TO MID
90S ACROSS MOST LOCATIONS...WITH HEAT INDEX VALUES APPROACHING 105
DEGREES FOR SOME LOCATIONS. SHOWERS AND THUNDERSTORMS LOOK TO DEVELOP
LATER THIS AFTERNOON AS A WEAK FRONT PUSHES THROUGH THE REGION. SOME
SEVERE STORMS ARE POSSIBLE AS AMPLE INSTABILITY WILL BE IN PLACE. THE
PRIMARY RISK WITH THESE STORMS WILL 60-70 MPH WIND GUSTS...HAIL...AND
FREQUENT LIGHTNING. THE ONLY ADJUSTMENT TO THE CURRENT FORECAST WAS
TO SLIGHTLY LOWER TEMPS FOR A FEW LOCATIONS. /27/


&&

.AVIATION...VFR CONDITIONS WILL CONTINUE TO PREVAIL LATE THIS
MORNING INTO AT LEAST THE FIRST HALF OF THE AFTERNOON.  CONVECTION
IS EXPECTED TO DEVELOP NORTH OF THE AREA AND SPREAD SOUTH THROUGH
THE LATE AFTERNOON AND EVENING HOURS AS A COLD FRONT DROPS SOUTH
THROUGH THE REGION.  THESE STORMS COULD BE SEVERE AND CAPABLE OF
PRODUCING DAMAGING WINDS AND HAIL.  MVFR TO LIFR CEILINGS AND/OR
VISIBILITIES WILL BE LIKELY AT SITES THAT OBSERVE CONVECTION DURING
THIS TIME.  WINDS BEHIND THE FRONT WILL BECOME NORTHERLY LATE
TONIGHT INTO FRIDAY. /19/


&&

.PREV DISCUSSION... /ISSUED 344 AM CDT THU JUN 13 2013/

SHORT TERM...TODAY THROUGH FRIDAY NIGHT...THE PRIMARY CONCERN FOR
THIS PERIOD WILL BE THE SEVERE WEATHER RISK FOR THIS AFTERNOON INTO
THIS EVENING. THE SECONDARY CONCERN WILL BE ANOTHER HOT/MUGGY DAY
FOLLOWED BY LESS HUMID CONDITIONS FOR FRIDAY. THIS FOLLOWED BY POPS
AND TEMPS.

LATEST SATELLITE SHOWS A RIDGE AXIS IN ALL LEVELS OF THE ATMOSPHERE
BRINGING MUGGY CONDITIONS ACROSS THE REGION FOR EARLY THIS MORNING.
A SHORT WAVE WAS PUSHING SOUTHEAST ACROSS THE MID MISSISSIPPI VALLEY WHICH
WILL AFFECT OUR REGIONAL WEATHER LATER TODAY. ON THE SURFACE THE REGION
WAS UNDER THE INFLUENCE OF HIGH PRESSURE CENTERED OVER THE CENTRAL
GULF.

AN ACTIVE STORMY DAY IS SHAPING UP FOR LATE THIS AFTERNOON INTO
THE EVENING HOURS. BEFORE CONVECTION FIRES...CONDITIONS WILL BE
WARM/HUMID AND LIKELY THE MOST WARMEST DAY SO FAR THIS WEEK. THE
HOTTEST TEMPS OF THE WEEK ARE EXPECTED WITH HIGHS 94-96 DEGREES
WITH DEWPOINTS IN THE LOWER TO MID 70S...WHICH WILL MAKE IT QUITE
HUMID. THIS WILL BRING HEAT INDEXES TOWARD 105 DEGREES. THIS WILL
APPROACH HEAT ADVISORY CRITERIA...BUT DUE TO THE SHORT DURATION AND
OTHER FACTORS...WILL NOT ISSUE ANY ADV AT THIS TIME. AREA SOUNDINGS
SHOWS THAT THE REGION WILL BE QUITE CAP FROM THE MORNING UNTIL
AROUND MID AFTERNOON WITH 700 MB TEMPS OF 10-13C. BUT THE CAP IS
EXPECTED TO WEAKENED FROM NORTH TO SOUTH FROM MID AFTERNOON THROUGH
THE EVENING.

NATIONAL WRF MODELS SHOWS THAT AN OUTFLOW BOUNDARY ALONG WITH A WEAK
FRONT WILL MAKE ITS WAY SOUTH ACROSS THE REGION. IT SHOWS SOME
SEVERE STORMS PRESSING SOUTH SOUTH ACROSS THE REGION WITH SOME
OF THE STORMS PUSHING SOUTHEAST ACROSS THE EAST HALF...WHILE SOME OF
THE SEVERE STORMS PRESSING SOUTHWEST OVER THE WEST HALF OF THE
REGION IN AN OUTFLOW BOUNDARY. IT WILL RUN INTO AN UNSTABLE AIRMASS AS IT
BRINGS IN A NASTY LINE OF STORMS ACROSS THE REGION DURING THE LATE
AFTERNOON TO EVENING HOURS. ITS LOOKS LIKE THE STORMS SHOULD BEGIN
NORTH OF THE CWA AT AROUND 4-5 PM AND HEAD SOUTH THROUGH THE REGION
BY 10 PM THIS EVENING. THE STORMS SHOULD BECOME SEVERE RAPIDLY AS
THEY PUSH INTO THE CWA THROUGH THE EVENING. THE AREA OF IMPACT HAS
CHANGED...EXPECT THE WHOLE REGION TO HAVE SOME POSSIBLE SEVERE RISK.
INITIALLY...LARGE HAIL WILL BE POSSIBLE...THEN TRANSITION TO
MORE OF A GENERALLY OR SMALL HAIL THREAT. LASTLY...FREQUENT LIGHTING
WILL BE POSSIBLE. LOOKING AT SOME OF THE INSTABILITY FACTORS. MODEL
SOUNDINGS SHOWS THAT THE EL LEVELS WILL BE DEEP AROUND
45-50KFT...WHICH SPELL TOPS AT 50KFT PLUS. 0-6 KM SHEAR AS WELL AS A
BELT OF MID TO UPPER LEVEL WINDS WILL BE AROUND 30-35 KNOTS FOR SOME
ORGANIZED SEVERE STORM POTENTIAL AND MULTI STORM CLUSTERS. SBCAPES
WILL BE >5000 J/KG...ML CAPE >4000...LIFT INDEXES AROUND
-10...SIGNIFICANT SEVERE POTENTIAL 60-80 KFT...DCAPES AROUND 2000.
THE PRIMARY RISK WILL BE 60-70 MPH GUSTY WINDS...HAIL AND FREQUENT
LIGHTNING. THUS WILL CONTINUE TO ADVERTISE THE POTENTIAL FOR ROBUST
STORMS/SEVERE WX. AS FAR AS POPS ARE CONCERN KEPT CURRENT FORECAST
POPS FOR THE PERIOD...SINCE MAV POPS WERE RATHER DRY AND NAM POPS
WERE A LITTLE LOW. FOR TEMPS WENT WITH CURRENT FORECAST FOR TODAY AND
MAV GUIDANCE FOR TONIGHT. HIGHS WILL BE IN THE MIDDLE 90S...AND LOWS
IN THE MIDDLE 60S TO LOWER 70S FOR TONIGHT.

FOR FRIDAY INTO FRIDAY NIGHT...EXPECT LESS WARM/HUMID CONDITIONS IN
THE WAKE OF THE WEAK FRONT. IN THE WAKE OF THE EXPECTED ROUND OF
STORMS...DRIER AND SLIGHTLY COOLER AIR WILL FILTER INTO THE AREA.
TEMPS WILL RANGE FROM THE UPPER 80S N TO LOWER 90S S. SFC DEWPTS
WILL FALL INTO THE 60S AND KEEP HUMIDITY WAY DOWN. THIS WILL ALSO
RESULT IN A COOL NIGHT FRI WITH LOWS IN THE LOWER/MID 60S.
WENT CLOSE TO MAV GUIDANCE ON POPS AND TEMPS. /17/

LONG TERM...SATURDAY THROUGH THURSDAY...WARM AND DRY CONDITIONS
WILL CONTINUE FOR THE BEGINNING OF THE PERIOD AS THE ARKLAMISS
REGION WILL BE ENTRENCHED UNDERNEATH A 592DM RIDGE. THIS WILL MAKE
FOR TEMPERATURES IN THE MID 90S AND VERY LIMITED RAIN CHANCES.
HOWEVER...THE PATTERN WILL BEGIN TO CHANGE BY LATER SUNDAY AND
CONTINUING THROUGH THE REMAINDER OF THE WEEK. THE UPPER RIDGE WILL
BREAK DOWN AS A PROGRESSIVE SHORTWAVE TROUGH MOVES ACROSS THE GREAT
LAKES REGION. THIS WILL BRING A WEAK COOL FRONT TOWARD OUR REGION
FOR TUESDAY. MODELS SHOW THIS FRONT STALLING ACROSS THE NORTHERN
SECTIONS OF THE CWA. SEVERAL DISTURBANCES WILL MOVE ALONG THIS FRONT
THROUGH THE END OF THE PERIOD...LEADING TO A CHANCE FOR SHOWERS AND
THUNDERSTORMS EACH DAY.  WITH THE BREAKDOWN OF THE UPPER RIDGE...AND
THE INCREASED CHANCES FOR RAIN...TEMPERATURES SHOULD BE SLIGHTLY
COOLER/CLOSER TO BUT STILL A LITTLE ABOVE SEASONAL NORMALS/ IN THE
90-93 DEGREE RANGE. /28/

&&


.PRELIMINARY POINT TEMPS/POPS...
JACKSON       95  71  91  65 /   8  56   5   8
MERIDIAN      95  69  91  61 /  11  61   4   9
VICKSBURG     95  69  92  62 /   4  43   5   8
HATTIESBURG   96  74  94  65 /   5  41   7   3
NATCHEZ       94  72  92  66 /   4  30  11   5
GREENVILLE    96  70  89  65 /  30  28   4   6
GREENWOOD     96  68  88  62 /  56  35   3   8

&&

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

&&

$$

27/19/17/28