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000
FXUS64 KJAN 122030
AFDJAN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
330 PM CDT WED JUN 12 2013

...SEVERE STORMS LIKELY LATE THURSDAY AFTERNOON INTO THURSDAY
EVENING...

.DISCUSSION...THE MAIN FOCUS FOR THIS FORECAST WILL BE ON THE SEVERE
WEATHER RISK TOMORROW. THE OTHER ITEMS OF INTEREST IN THE FORECAST
WILL BE ANOTHER HOT/HUMID/STEAMY DAY TOMORROW FOLLOWED BY LESS
HOT/HUMID CONDITIONS FOR FRI-SAT.

HOT & HUMID CONDITIONS ACROSS THE CWA THIS AFTERNOON WITH TEMPS IN
THE LOWER/MID 90S AND HEAT INDICES 97-103 AS THE MID/UPPER LEVEL
HIGH CONTROLS THE WEATHER. A BIT OF RELIEF CAN BE EXPECTED TONIGHT
AS SKIES CLEAR AND TEMPS SLOWLY SETTING INTO THE 70S. STILL...LOWS
TONIGHT WILL BE ON THE WARM SIDE AS MORE OF A WESTERLY COMPONENT TO
THE LOW LEVEL FLOW DEVELOPS AND OUR REGION GETS SITUATED IN THE
THERMAL AXIS AHEAD OF A SFC FRONTAL BOUNDARY. DUE TO THIS...LOWS
WERE BUMPED UP FROM GFS GUID.

AN ACTIVE CONVECTIVE DAY IS SHAPING UP FOR LATE THU AFTERNOON INTO
THE EVENING OURS. BEFORE CONVECTION FIRES...CONDITIONS WILL BE
HOT/HUMID AND LIKELY THE MOST OPPRESSIVE DAY SO FAR THIS WEEK. THE
HOTTEST TEMPS OF THE WEEK ARE EXPECTED WITH HIGHS 94-96 DEGREES.
WHAT WILL MAKE IT WORSE WILL BE THE HUMIDITY. LOW LEVEL MOISTURE
WILL POOL JUST AHEAD OF A SOUTHWARD SAGGING SFC FRONT WHICH WILL
KEEP SFC DEWPTS 72-75 DEGREES (IF NOT A TAD HIGHER). THIS WILL ALLOW
HEAT INDEX VALUES TO MAKE A RUN AT 105 DEGREES. THIS WILL APPROACH
ADV CRITERIA...BUT DUE TO THE SHORT DURATION AND OTHER
FACTORS...WILL NOT ISSUE ANY ADV AT THIS TIME.

SOME FORECAST GUID CONTINUE TO INDICATE THE POTENTIAL FOR A NASTY
BOUT OF STORMS THU AFTN/EVE. NOT ALL MODEL DATA ACTUALLY DEVELOP
CONVECTION DUE TO THE VARIOUS CONVECTIVE SCHEMES EACH RUN AND THE
FACT THAT SOME OF OUR AREA WILL BE ON THE EDGE OF CONDITIONS THAT
COULD KEEP STORMS FROM FIRING AT ALL. STILL...ENOUGH INFORMATION
EXISTS FOR HIGHER CONFIDENCE AND TO LEAN MORE ON THE CONVECTIVE
ALLOWING MODELS WHICH BREAK OUT STORMS. AS DISCUSSED ABOVE...HIGH
HEAT/HUMIDITY WILL BE IN PLACE AND THIS COMBINATION LOOKS TO YIELD
SBCAPE OF 4000-5000 J/KG (MLCAPE 3000-3800) WHICH ARE IN THE EXTREME
RANGE. SFC LI`S LOOK TO RANGE FROM -8 TO -10C WITH THE LOWEST LI`S
LIKELY -10 TO -12C AND OCCURRING ABOVE 500MB. WITH SUCH LARGE(THICK)
CAPE PROFILES...INTENSE UPDRAFTS WILL BE POSSIBLE WHERE CAPPING CAN
BE REMOVED. EXPECTATIONS ARE SUCH THAT CONVERGENCE ALONG THE SFC
BOUNDARY AT PEAK HEAT WILL DO JUST THAT ALONG WITH AIDED ASCENT FROM
A S/WV ROUNDING THE RIDGE. RECENT TRENDS SUPPORT A BIT MORE VIGOROUS
S/WV AS MID LEVEL HEIGHT FALLS ARE NOW AROUND 20M.
ADDITIONALLY...MID LEVEL FLOW WILL BE 25-35 KTS WHICH WILL SUPPORT
ORGANIZED UPDRAFTS AND MULTICELL STORM CLUSTERS.
ADDITIONALLY...DCAPE VALUES WILL BE QUITE HIGH AND LIKELY IN THE
1200-1600 J/KG RANGE. THIS WILL SUPPORT STRONG DMG WIND
POTENTIAL...ESPECIALLY WHEN COMBINED WITH THE STRONG MID LEVEL FLOW
AND EXTREME INSTABILITY. THERE STILL REMAINS SOME NEGATIVE ELEMENTS
WHICH COULD KEEP CONVECTION IN CHECK OR MORE FOCUSED TO THE EAST OF
THE CWA. HOWEVER...MORE FAVORABLE ELEMENTS EXIST AND THUS WILL
CONTINUE TO ADVERTISE THE POTENTIAL FOR ROBUST STORMS/SEVERE WX.

AS FOR SOME SPECIFICS...CONFIDENCE IS HIGHER THAN NORMAL ON TIMING
AND GENERAL LOCATION THANKS TO CAPPING AND LOW LEVEL FORCING
LOCATION. STORM(CONVECTIVE) INITIATION LOOKS TO OCCUR AROUND 4-5PM
NEAR OR JUST TO THE NORTH OF OUR CWA. STORMS SHOULD BECOME SEVERE
RAPIDLY AND EVOLVE GENERALLY S/SE INTO THE EVENING. THE AREA OF
GREATEST IMPACT REMAINS THE SAME AND WE WILL CONTINUE TO HIGHLIGHT
THAT AREA IN THE GRAPHICS. STILL...AREAS JUST ON THE OUTSIDE/FRINGE
OF THAT SHADING...COULD SEE SOME STRONG/SVR STORMS AS WELL. WE WILL
REFINE THE OUTLOOK FURTHER AS MORE NEAR TERM HI-RES DATA BECOMES
AVAILABLE. EXPECTATIONS ARE FOR A HIGHER END WIND EVENT WITH
DAMAGING WINDS OF 60-70 MPH BEING THE MAIN THREAT. INITIALLY...LARGE
HAIL WILL BE POSSIBLE...THEN TRANSITION TO MORE OF A GENERALLY OR
SMALL HAIL THREAT. LASTLY...FREQUENT LIGHTING WILL BE POSSIBLE.

CONFIDENCE HAS ALSO INCREASED FOR THE FRI-SAT PERIOD AND IT HAVING
LESS PRECIP POTENTIAL ALONG WITH LESS HOT/HUMID CONDITIONS. THIS
GOOD NEWS COMES JUST IN TIME FORE THE WEEKEND AS WELL. 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. IN TURN...HIGH TEMPS ON SAT WILL ALSO BE HELD IN CHECK A BIT
AND TOP OUT IN THE LOWER 90S. /CME/

&&

.AVIATION...VFR CONDITIONS WILL CONTINUE TO PREVAIL THIS AFTERNOON
THROUGH AT LEAST THURSDAY MORNING.  SOUTHWESTERLY WINDS WILL SUBSIDE
A BIT IN MOST LOCATIONS...GENERALLY RANGING FROM 0-5 KNOTS
OVERNIGHT.  PATCHY FOG WILL BE POSSIBLE AT SOME SITES AROUND DAY
BREAK THURSDAY. /19/

&&

.PRELIMINARY POINT TEMPS/POPS...
JACKSON       73  95  71  91 /   0   8  56   5
MERIDIAN      70  95  70  91 /   1  11  61   3
VICKSBURG     72  96  69  92 /   0   4  43  11
HATTIESBURG   72  96  72  94 /   5   5  41   7
NATCHEZ       73  94  70  92 /   0   4  30  10
GREENVILLE    74  96  69  89 /   0  30  28  11
GREENWOOD     74  96  67  88 /   0  56  35   3

&&

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

$$

CME/19