Area Forecast Discussion
Issued by NWS Jackson, MS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS64 KJAN 221538 AAA
AFDJAN

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON MS
1038 AM CDT TUE JUL 22 2014

.DISCUSSION...COLD CORE LOW WILL CONTINUE TO RETROGRADE INTO THE
ARKLAMISS FROM THE EAST THROUGH THE COURSE OF THE DAY.  DEEPER
MOISTURE FILTERING IN FROM THE EAST COMBINED WITH DAYTIME HEATING
LOOKS TO YIELD CAPE VALUES AROUND 2000 J/KG THIS AFTERNOON WHICH IS
ADEQUATE TO SUPPORT A DECENT COVERAGE OF CONVECTION THROUGH THE
AFTERNOON HOURS...PARTICULARLY OVER AREAS ALONG AND EAST OF THE
NATCHEZ TRACE PARKWAY WERE AN AXIS OF BETTER LOW LEVEL MOISTURE
CONVERGENCE LOOKS TO EXIST.  PRECIPITABLE H2O VALUES CLIMBING BACK
UP TO THE 1.75-2.00 INCH RANGE WILL SUPPORT THE POTENTIAL FOR SOME
LOCALIZED HEAVY RAINFALL.

MODEST MID-LEVEL FLOW ON THE ORDER OF 30-35 KNOTS AND ADVERTISED 30
KNOTS 0-6KM BULK SHEAR COULD AID IN SOME HEALTHY CORES THIS AFTERNOON
THAT`LL BE CAPABLE OF PRODUCING SOME GUSTY WINDS. THE LASTEST BATCH
OF HIGH-RES MODELS SEEM TO BE PICKING UP ON THIS TREND AS THEIR
CONVECTIVE OUTPUT IS A BIT MORE ROBUST THAN PREVIOUS RUNS. THIS
ACTIVITY IS EXPECTED TO GRADUALLY SUBSIDE IN BOTH INTENSITY AND
COVERAGE AS DAYTIME HEATING IS LOST THIS EVENING.

THE ONLY NOTABLE CHANGES TO THE FORECAST FOR TODAY...ASIDE FROM THE
TYPICAL HOURLY TRENDS...IS TO INCREASE POPS IN AREAS MAINLY ALONG
AND EAST OF THE NATCHEZ TRACE PARKWAY.  OTHERWISE...REMAINING
ELEMENTS OF THE CURRENT FORECAST LOOK GOOD FOR TODAY. /19/

&&

.AVIATION...CONVECTION WILL INCREASE FROM THE EAST THIS AFTERNOOON...
BUT NO MORE THAN VICINITY EXPECTED AT TAF SITES. SOME MVFR CEILINGS
WILL BE POSSIBLE BETWEEN GTR AND MEI EARLY THIS AFTERNOON...OTHERWISE
VFR CONDITIONS WILL PREVAIL INTO THE EVENING AS CONVECTION WINDS
DOWN. THEREAFTER...MVFR CEILINGS IN THE EAST AND MVFR VISIBILITIES
EVERYWHERE WILL BE THE RULE UNTIL AROUND 14Z. /26/

&&

.PREV DISCUSSION... /ISSUED 529 AM CDT TUE JUL 22 2014/

SHORT TERM...THE PRIMARY WEATHER FEATURE AFFECTING THE ARKLAMISS
WILL BE A CLOSED COLD CORE LOW MIGRATING WESTWARD FROM AL INTO MS.
THERE IS A WEAK SURFACE REFLECTION THAT WILL AID IN LOW LEVEL
MOISTURE CONVERGENCE OVER EASTERN MS LATER THIS MORNING AND
AFTERNOON AS DEEPER MOISTURE SURGES WESTWARD TOWARD THE INTERSTATE
55 CORRIDOR AND COMBINES WITH DAYTIME HEATING. HRRR GUIDANCE
INDICATES CAPE VALUES PEAKING IN THE 2000-3000 J/KG RANGE AND
PRECIPITABLE WATER APPROACHING TWO INCHES - AND THIS WILL SUPPORT
THUNDERSTORM INITIATION ALONG THE LL MOISTURE CONVERGENCE AXIS
STRETCHING NORTH OF THE LOW CENTER. HIGH-RES MODEL OUTPUT VARIES IN
COVERAGE BUT THERE MAY BE SUFFICIENT EASTERLY MID LEVEL FLOW TO
SUPPORT MULTI-CELL STORM CLUSTERS ALONG ANY BOUNDARIES WITH STORMS
CAPABLE OF PRODUCING SOME STRONG WIND GUSTS. THE MOVEMENT OF STORMS
IN THIS FLOW PATTERN WOULD INCREASE RAINFALL COVERAGE AND HAVE
RAISED POPS SOME FOR TODAY.

EXPECT CONVECTIVE ACTIVITY TO WANE AFTER SUNSET THIS EVENING. THE
CLOSED LOW WILL CONTINUE ITS WESTWARD MIGRATION OVERNIGHT AND BETTER
MOISTURE CONVERGENCE SHOULD SET UP FARTHER WEST WEDNESDAY...AND HAVE
SHIFTED POPS SLIGHTLY IN THAT DIRECTION - A LITTLE MORE THAN MOS
GUIDANCE SUGGESTS. THE THERMODYNAMIC AND WIND PROFILES SHOULD BE
SIMILAR WEDNESDAY AND A FEW STRONG STORMS WOULD BE A POSSIBILITY
ONCE AGAIN. IT LOOKS LIKE NORTHERN STREAM SHORTWAVE ENERGY
APPROACHING THE AREA LATE WEDNESDAY NIGHT IS A LITTLE SLOWER IN THE
MODEL GUIDANCE...AND THE GREATER INFLUENCE ON ARKLAMISS WEATHER MAY
HOLD OFF UNTIL THURSDAY. HAVE RAISED POPS ABOVE GUIDANCE TO MAINTAIN
SOME CONTINUITY...ESPECIALLY WITH THE POSSIBILITY OF CONVECTIVE COLD
POOLS THAT COULD HELP TO SEND SHOWER/TSTM ACTIVITY A LITTLE FARTHER
SOUTH THAN EXPECTED INTO NRN PORTIONS OF THE AREA. /EC/

LONG TERM...THURSDAY TO TUESDAY. SO FAR...NO BIG PATTERN CHANGE FOR
THE REGION. WITH THE LARGE AREA OF HIGH PRESSURE PLANTED OVER THE
ROCKIES...THE ARKLAMISS WILL CONTINUE TO GET FRONTS AND WEAK
DISTURBANCES EVERY FEW DAYS. THE MOS CONTINUES TO BOUNCE AROUND WITH
THE TEMPERATURES. PERHAPS LEANING MORE TOWARD CLIMATOLOGY FOR THIS
TIME OF YEAR...THE TEMPS IN THE EXTENDED ARE BACK INTO THE UPPER
90S/MID 70S EARLY NEXT WEEK WHICH WOULD SUGGEST POSSIBLE INCREASE IN
HEAT STRESS. HOWEVER...WITH THE CURRENT PATTERN TEMPERATURES ARE
LIKELY TO BE AT OR BELOW NORMAL THROUGH THE EXTENDED. STUCK WITH
GUIDANCE GENERALLY FOR POPS AND TEMPS.

BY THURSDAY...IT LOOKS LIKE THE LATEST STALLED FRONT WILL BE
REPLACED WITH AN APPROACHING COLD FRONT. THIS BOUNDARY IS LIKELY TO
STALL ALONG THE COAST OVER THE WEEKEND...BEFORE THE NEXT FRONT MOVES
INTO THE REGION AROUND MONDAY. EACH SYSTEM SEEMS TO BE LACKING MUCH
UPPER LEVEL SUPPORT AND THE MAIN SURFACE LOW WITH EACH SYSTEM IS
ALSO DISTANT. HOWEVER...THE MODELS ARE BRINGING IN PLENTY OF VERY
MOIST AND UNSTABLE AIR FROM THE GULF. THERE IS A CHANCE OF RAIN
ACROSS THE AREA NEARLY EVERY DAY. WITH THE BEST DYNAMICS ASSOCIATED
WITH THE SYSTEMS STAYING TO THE NORTH AND THE WESTERN RIDGE WAVERING
FURTHER EAST SOME DAYS...MUCH OF THE THUNDERSTORM ACTIVITY WILL MISS
THE WESTERN ZONES...BASICALLY AREAS EAST OF INTERSTATE 55 THROUGH
THE PERIOD. OF COURSE THERE COULD BE SOME ISOLATED TO SCATTERED
THUNDERSTORMS...BUT POPS RIGHT NOW ARE LOW. BETWEEN EACH FRONT WILL
BE A DAY OR TWO OF MOSTLY CLEAR SKIES AND MILD CONDITIONS. NOT
ANTICIPATING A PATTERN SHIFT THIS FORECAST PERIOD.

&&

.PRELIMINARY POINT TEMPS/POPS...
JACKSON       90  71  91  71 /  46  32  34  22
MERIDIAN      88  69  91  69 /  60  39  28  23
VICKSBURG     90  70  92  71 /  20  20  34  22
HATTIESBURG   90  70  92  71 /  60  25  26  21
NATCHEZ       89  70  90  71 /  21  15  38  20
GREENVILLE    92  72  93  73 /  16  12  24  27
GREENWOOD     91  71  91  72 /  25  21  29  27

&&

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

$$

19/26





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.