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000
FXUS64 KJAN 162144
AFDJAN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
436 PM CDT THU MAY 16 2013

.DISCUSSION...UPPER LOW CURRENTLY CENTERED OVER NORTHWEST ARKANSAS
WILL PLAY A BIG PART IN THE WEATHER FOR PORTIONS OF THE REGION OVER
THE NEXT 36 HOURS OR SO. ALTHOUGH THIS LOW CENTER IS FAR TO OUR
NORTHWEST...THE SOUTHERN EXTENT OF THE FEATURE WILL SWEEP ACROSS OUR
AREA THROUGH LATE TOMORROW AS THE WHOLE SYSTEM TRACKS EAST. PLENTY
OF WARM...MOIST AND UNSTABLE AIR WILL BE DRAWN NORTH FROM THE GULF
INTO OUR FORECAST AREA AS THE SYSTEM MOVES ACROSS...HELPING TO
INCREASE VIGOROUS THUNDERSTORM POTENTIAL.

RIGHT NOW THE FAR SOUTHEAST FRINGE OF THE DISTURBANCE IS HELPING
KICK OFF SOME SHOWERS AND EMBEDDED WEAKER STORMS AFFECTING SE
MS...BUT THIS ACTIVITY WILL LIKELY MOVE EAST INTO ALABAMA BY EARLY
EVENING. THE BIGGER CONCERN IS OFF TO OUR WEST WHERE A POTENT
SUPERCELL IS MARCHING EAST SOUTHEAST THROUGH NORTHERN LOUISIANA.
THERE IS ENOUGH SHEAR AND INSTABILITY OUT THERE TO FUEL SEVERE
STORMS...AND THIS STORM HAS INDEED BEEN PRODUCING REPORTS OF HAIL
AND HIGH WINDS. THE ATMOSPHERE BECOMES LESS UNSTABLE AS YOU GO EAST
INTO NORTHEASTERN LA (OUR CWA) AND DRY AIR ABOVE THE GROUND IS MORE
ABUNDANT. THUS...THE CURRENT THINKING IS THAT THE CELL WILL WEAKEN
SOMEWHAT OR COMPLETELY FALL APART BEFORE GETTING INTO OUR REGION. WE
WILL BE WATCHING THE SITUATION CLOSELY...BUT AS OF NOW DO NOT REALLY
ANTICIPATE SEVERE WEATHER GETTING INTO OUR REGION THIS EVENING.

LATER TONIGHT THERE COULD DEFINITELY BE SOME MORE WIDESPREAD SHOWERS
AND EMBEDDED STORMS DEVELOPING IN THE NORTHERN PORTIONS OF OUR
FORECAST AREA AS THE SYSTEM NEARS. AS WITH STUFF FURTHER SOUTH THIS
EVENING...SOME OF THESE STORMS IN THE ARKLAMISS DELTA LATE COULD BE
A LITTLE POTENT WITH SOME GUSTY WINDS OR SMALL HAIL BUT ARE ALSO NOT
EXPECTED TO BE SEVERE. OTHERWISE TONIGHT WILL BE QUITE MILD WITH
LOWS WAY UP IN THE 60S. SOME FOG IS NOT INCONCEIVABLE IN SOUTHEAST
MS LATE TONIGHT...BUT IN GENERAL LOW CLOUDS SHOULD BE MORE OF THE
MODE COME SUNRISE.

TOMORROW THE UPPER LOW AXIS WILL BE SITUATED IN A WAY WHERE MOISTURE
SHOULD SPILL MORE EFFECTIVELY INTO THE REGION FROM THE SOUTH AND
SOUTHWEST. CAPPING WILL INCREASE AS THIS HAPPENS...BUT INSTABILITY
WILL BUILD AS WELL. ASIDE FROM NORTHEAST ZONES IN MS THIS CAPPING
WILL BE HARD TO OVERCOME WITHOUT A SOLID TRIGGER...BUT COLD POOL
BOUNDARIES FROM MORNING CONVECTION AROUND NORTHERN PORTIONS OF THE
AREA WILL LIKELY CREEP SOUTH TO PROVIDE SUCH IMPETUS LATER IN THE
AFTERNOON. CHANCES OF CONVECTION WILL BE LESS IN NE LA AND SW MS IN
COMPARISON TO NE MS...BUT CONDITIONAL CHANCES OF SEVERE WEATHER
MIGHT ACTUALLY BE GREATER IN THE SOUTHWEST DUE TO BETTER INSTABILITY
AND HIGHER NEGATIVE BUOYANCY POTENTIAL OF TSTORM DOWNDRAFTS. SHEAR
WILL BE MARGINAL FOR GETTING TRUE SUPERCELL FORMS...BUT A ROGUE
SUPERCELL (MUCH LIKE IS OCCURRING AT PRESENT IN NORTHERN LA) IS
DEFINITELY NOT OUT OF THE QUESTION. THAT KIND OF STORM IN OUR AREA
TOMORROW WOULD POSE A LARGE HAIL...DAMAGING WIND AND STRAY TORNADO
RISK. OTHERWISE...THE LARGER RISK WILL COME FROM THUNDERSTORM
CLUSTERS CAPABLE OF PRODUCING HIGH WINDS...LOCALLY HEAVY RAINFALL
AND EVEN SOME HAIL. THE HWO AND GRAPHICASTS CONCENTRATE ON THESE
RISKS FOR TOMORROW.

ACTIVITY COULD CONCEIVABLY WAIT UNTIL LATE IN THE AFTERNOON TO
REALLY BREAK OUT VIGOROUSLY IN MANY SPOTS OF THE REGION AND THUS
COULD GO WELL INTO THE EVENING HOURS. 850 MB THETA E ADVECTION
VECTORS POINTING EAST NORTHEAST INTO THE BACKSIDE OF THE SYSTEM
TOMORROW EVENING INTO TOMORROW NIGHT SUGGEST WE WILL REALLY HAVE TO
MONITOR POTENTIAL FOR HIGHLY CONCENTRATED...BUT VERY
HEAVY...RAINFALL. THIS WILL ESPECIALLY BE THE CASE OVERNIGHT UP NEAR
THE GOLDEN TRIANGLE AND ALONG THE HIGHWAY 45 CORRIDOR BETWEEN
COLUMBUS AND MERIDIAN.

BY SATURDAY THE UPPER LOW SHOULD REALLY BE QUITE EAST OF THE REGION
ALTHOUGH SOME SORT OF CONVECTIVELY-ENHANCED BOUNDARY MAY LINGER OVER
NORTHEAST PORTIONS OF THE CWA IN ITS WAKE. IF THAT DOES OCCUR THEN
THIS BOUNDARY COULD TRIGGER AT LEAST SOME ISOLATED STORMS IN
NORTHERN COUNTIES OF MS ZONES SATURDAY INTO SATURDAY EVENING.
OTHERWISE...ANTICIPATE VERY WARM CONDITIONS WITH HIGHS PERHAPS
GETTING CLOSE TO OR EVEN TOUCHING THE 90 DEGREE MARK IN A FEW
LOCATIONS. /BB/

&&

.PREV DISCUSSION... /ISSUED 403 AM CDT THU MAY 16 2013/

LONG TERM...MEX POPS WERE CUT AND THE FORECAST WAS LEFT DRY FOR
SUNDAY WHEN CAPPING AND UPPER RIDGING WILL BECOME MORE DOMINANT.
UPPER RIDGING WILL BEGIN TO EDGE TO THE EAST MONDAY BUT CAPPING WILL
CONTINUE ALONG WITH A RELATIVELY DRY AIR MASS.

MODEL DIFFERENCES BECOME MORE EVIDENT LATE IN THE EXTENDED PERIOD.
THE EURO PIVOTS A MORE AMPLIFIED UPPER TROUGH...AND ASSOCIATED
SURFACE BOUNDARY...INTO THE REGION TUESDAY EVENING INTO WEDNESDAY
WHILE THE GFS FLATTENS FLOW ALOFT AND KEEP THE SURFACE FORCING WELL
TO OUR W AND N. ALTHOUGH DISCREPANCIES EXIST REGARDING THE STRENGTH
OF FORCING THAT WILL DEVELOP BY WEDNESDAY...BOTH MODELS INDICATE AT
LEAST SLIGHTLY CYCLONIC SWLY FLOW ALOFT AND DECAYING CAPPING.
AFTERNOON HEATING WILL NECESSITATE AT LEAST ISOLATED CONVECTION IN
THIS ENVIRONMENT WITH DECENT CAPE/LAPSE RATES AND INCREASING
DEWPOINTS. MEX MOS...REFLECTING A LESS AMPLIFIED PATTERN...HAS COME
IN RELATIVELY DRY FOR WEDNESDAY ON THIS RUN. WILL ADD ISOLATED
CONVECTION TO THE FORECAST AREA FOR WEDNESDAY FOR NOW WITH SLIGHTLY
HIGHER POPS OVER NWRN ZONES DUE TO THE PROXIMITY TO REGIONS OF
POTENTIALLY BETTER FORCING.

TEMPERATURES WILL BE UNDERGO A GRADUAL WARMING TREND THIS WEEKEND
BUT WILL REMAIN SLIGHTLY BELOW NORMALS FOR THIS TIME OF YEAR. SOLID
UPPER RIDGING WILL BE RELATIVELY BRIEF AND DAMP SOIL CONDITIONS WILL
NOT PRODUCE MAXIMUM DAYTIME WARMING. CONFIDENCE IS LOW ON
TEMPERATURES FOR THE MID PART OF NEXT WEEK AS THE FRONTAL PASSAGE
ADVERTISED BY THE EURO WILL RESULT IN A SIGNIFICANTLY DIFFERENT
SOLUTION THAN IF THE AREA SITS IN PERSISTENT LOW LEVEL SLY FLOW OVER
THE NEXT WEEK OR SO. /03/

&&

.AVIATION...VFR CONDITIONS PREVAIL ACROSS ALL TAF SITES THIS
AFTERNOON. A FEW SHOWERS ARE CURRENTLY MOVING ACROSS THE AREA...BUT
EXPECT MAINLY VFR CONDITIONS TO CONTINUE THROUGH THE EVENING. THE
ONLY EXCEPTION WILL BE AT GLH WHERE SHOWERS AND THUNDERSTORMS ARE
POSSIBLE THIS EVENING. STRATUS WILL FORM OVER MUCH OF THE AREA EARLY
ON FRIDAY AND THIS WILL BRING WIDESPREAD MVFR/IFR CEILINGS FOR MOST
TAF SITES FROM 08-15Z. THE WINDS WILL GENERALLY BE OUT OF THE SOUTH
AT 5-10KTS BECOMING LIGHT OUT OF THE SOUTH OVERNIGHT./15/

&&

.PRELIMINARY POINT TEMPS/POPS...
JACKSON       67  83  69  89 /  29  43  25  10
MERIDIAN      65  82  65  88 /  20  52  35   9
VICKSBURG     68  84  68  89 /  40  27  19   8
HATTIESBURG   67  86  68  89 /  11  23  15   6
NATCHEZ       68  85  68  87 /  25  19  14   4
GREENVILLE    68  82  68  87 /  60  51  30  14
GREENWOOD     68  81  68  87 /  56  70  41  17

&&

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

$$

BB/15/03