Area Forecast Discussion
Issued by NWS Jackson, MS

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FXUS64 KJAN 020851
AFDJAN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
351 AM CDT THU APR 2 2015

.SHORT TERM...TODAY THROUGH FRIDAY NIGHT...WATER VAPOR IMAGERY THIS
MORNING IS SHOWING A SHORTWAVE OVER SE TX MOVING NE TOWARD THE AREA
WITH A RATHER EXTENSIVE PLUME OF MOISTURE OVERSPREADING THE AREA.
WARM ADVECTION FROM THIS WAVE IS MOST CONCENTRATED ABOVE 305K THETA
AND SOME LIGHT SHOWERS HAVE ALREADY BEEN SHOWING UP ON RADAR OVER SW
SECTIONS. MAJORITY OF THIS HAS NOT BEEN REACHING THE GROUND WITH
WARM/DRY INVERSION LAYER BELOW.

AS THE WAVE MOVES EAST/NORTHEAST...EXPECT LIGHT SHOWER ACTIVITY TO
CONTINUE THIS MORNING SERVING TO TEMPORARILY WASH AWAY THE LOW LEVEL
INVERSION...TAPERING OFF FROM THE SW THIS AFTERNOON. VEERING LOW
LEVEL WINDS AS THE WAVE PASSES WILL ALLOW THE LOW LEVEL INVERSION TO
QUICKLY REESTABLISH ITSELF OVERNIGHT.

MEANWHILE...NEAR ZONAL MID LEVEL FLOW WITH 120 KNOT H3 JET WILL
QUICKLY PUSH A RATHER POTENT WAVE OUT OF THE ROCKIES AND INTO THE
PLAINS BY DAYS END. SURFACE LOW PRESSURE WILL QUICKLY DEVELOP OVER
OK OVERNIGHT AND RACE INTO THE MID MS VALLEY FRIDAY MORNING DRAGGING
A FRONT BEHIND.

THE AIRMASS OVER THE FORECAST AREA LOOKS TO BE REMAIN CAPPED THROUGH
THE MAJORITY OF THE DAY FRIDAY. HOWEVER...DO EXPECT IT TO BREAK DOWN
IN THE NEIGHBORHOOD OF THE APPROACHING BOUNDARY AS MOISTURE
CONVERGENCE AND FRONTAL FORCING SHOULD BE SUFFICIENT TO ERODE THE
WARM LAYER AND ALLOW FOR CONVECTIVE DEVELOPMENT BY LATE AFTERNOON.
SEVERE POTENTIAL STILL LOOKS BEST OVER N MS WHERE DEEP LAYER SHEAR
WILL EXCEED 50 KNOTS...7-7.5 C/KM H7-H5 LAPSE RATES/25-30 VERTICAL
TOTALS...AND DIURNALLY OPTIMIZED SBCAPES AROUND 2000 J/KG WILL
EXIST. SEVERE MODE STILL LOOKS PREDOMINANTLY DAMAGING WINDS AND HAIL
AS LIMITED LOW LEVEL SHEAR WILL NOT BE SO FAVORABLE FOR TORNADOES.

CONVECTIVE LINE WILL MOVE SOUTHEAST ACROSS THE REMAINDER OF THE AREA
DURING THE EVENING AND CONTINUING INTO THE FAR SOUTH OVERNIGHT.
SEVERE THREAT WILL DIMINISH THE FURTHER SOUTHEAST IT GETS WITH TIME
DUE TO THE LOSS OF DAYTIME HEATING./26/

.LONG TERM...SATURDAY THROUGH THURSDAY...COOLER THAN NORMAL
TEMPERATURES ARE EXPECTED FOR THE WEEKEND BUT A RETURN TO WARMER THAN
NORMAL TEMPERATURES WILL ACCOMPANY THE START OF THE WORK WEEK AND
CONTINUE THROUGH THE END OF THE LONG TERM PERIOD.

MODEL CONSENSUS HAS THE COLD FRONT SOUTH OF OUR CWA BY SUNRISE
SATURDAY BUT POST FRONTAL PRECIPITATION LOOKS TO LINGER OVER THE
HIGHWAY 84 CORRIDOR THROUGH MID MORNING. THE REMAINDER OF THE AREA
WILL START THE LONG TERM PERIOD DRY. A 1030MB HIGH CENTERED OVER THE
OZARKS WILL SHIFT EAST TO THE TENNESSEE VALLEY BY SATURDAY EVENING
HELPING TO BRING A COOLER AND MUCH DRIER AIRMASS TO OUR CWA. PWS
WILL BE KNOCKED DOWN FROM GREATER THAN AN INCH AND A HALF AHEAD OF
THE COLD FRONT FRIDAY TO AROUND A QUARTER OF AN INCH BY NOON
SATURDAY. THE CAA IN THE WAKE OF THE FRONT WILL HOLD AFTERNOON HIGHS
IN THE 60S SATURDAY AND MORNING LOWS IN THE 40S SUNDAY. THE SURFACE
HIGH WILL SHIFT EAST TO THE MID ATLANTIC SEABOARD BY SUNDAY MORNING
RESULTING IN WEAK RETURN FLOW AHEAD OF AN APPROACHING SHORTWAVE.
THIS SOUTHERN STREAM SHORTWAVE IS EXPECTED TO BE MOVING ACROSS THE
SOUTHERN PLAINS SUNDAY MORNING. IT SHOULD TAKE MOST OF SUNDAY
MORNING TO MOISTEN OUR AIRMASS TO ALLOW FOR RAIN TO FALL OVER THE
WESTERN ZONES BY NOON AND THEN SPREAD EAST ACROSS THE REMAINDER OF
OUR CWA SUNDAY AFTERNOON. THE RAIN WILL CONTINUE SUNDAY NIGHT AS THE
SHORTWAVE SHIFTS EAST ACROSS THE REGION. BY MONDAY MORNING LOWER 60
DEGREE DEW POINTS AND INCH AND A HALF PWS WILL BE BACK OVER OUR CWA.
MONDAY THROUGH TUESDAY CONVECTION WILL BE MOSTLY DIURNALLY DRIVEN.
TUESDAY NIGHT THOUGH A NEARLY STATIONARY FRONTAL BOUNDARY WILL DRIFT
INTO THE NORTHERN PORTIONS OF OUR CWA AND SERVE TO FOCUS CONVECTION.
AS BROAD TROUGHING ALOFT REMAINS OVER THE WESTERN CONUS THE
RESULTING SOUTHWEST FLOW ALOFT LOOKS TO BRING SEVERAL SHORTWAVES
THAT WILL COMBINE WITH THE BOUNDARY...ABUNDANT MOISTURE AND DAYTIME
HEATING FOR PERIODS OF HEAVY RAIN WEDNESDAY AND THURSDAY. MODEL RUN
ACCUMULATIONS OF THE GFS AND ECMWF SHOW SEVERAL INCHES OF RAIN
DURING THIS PERIOD AND MAINLY NORTH OF INTERSTATE 20. /22/


&&

.AVIATION...MVFR CIGS/VSBYS THIS MORNING WILL GIVE WAVE TO VFR CIGS
BY 18Z. SCATTERED SHOWERS MAY TEMPORARILY REDUCE VSBYS TO MVFR
THROUGH THE PERIOD...BUT THEY WILL BE BRIEF. WINDS WILL BE QUITE
GUSTY THIS AFTERNOON AS 15-20 KNOTS SUSTAINED AND GUSTS OF 25-35
KNOTS WILL BE COMMON...ESPECIALLY NEAR GLH./26/


&&

.PRELIMINARY POINT TEMPS/POPS...
JACKSON       83  65  83  48 /  24  10  35  72
MERIDIAN      81  61  82  46 /  20  14  23  64
VICKSBURG     83  66  81  47 /  23  11  43  71
HATTIESBURG   83  63  83  56 /  18   8  20  44
NATCHEZ       84  67  83  48 /  19  10  33  62
GREENVILLE    80  65  77  44 /  27  18  64  48
GREENWOOD     81  66  79  44 /  33  20  58  60

&&

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

$$



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