Area Forecast Discussion
Issued by NWS Jackson, MS

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FXUS64 KJAN 301538 AAA
AFDJAN

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON MS
1038 AM CDT SAT MAY 30 2015

.DISCUSSION...THE ONGOING FORECAST IS IN GOOD SHAPE OVERALL.  SOME
SHOWERS AND STORMS HAVE ALREADY BEGUN TO DEVELOP OVER THE FORECAST
AREA THIS MORNING.  MUCH OF THIS ACTIVITY IS PRIMARILY NORTH OF THE
INTERSTATE 20 CORRIDOR WHERE BETTER MOISTURE CONVERGENCE EXISTS
ALONG A WEAK BOUNDARY.  THIS IN TURN IS ASSOCIATED WITH A WAVE OF
ENERGY THAT`S LIFTING NORTHEAST OUT OF CENTRAL ARKANSAS TOWARD
SOUTHEAST MISSOURI.

AS LATE MORNING GIVES WAY TO THE AFTERNOON HOURS...DAYTIME HEATING
IN THIS MOIST AIRMASS WILL PROVIDE ADEQUATE INSTABILITY IN THIS
OVERALL TROUGHING PATTERN...TO SUPPORT A GOOD COVERING OF SCATTERED
SHOWERS AND STORMS ACROSS THE CWA THROUGHOUT THE AFTERNOON.  THE
COMPLEX OF SHOWERS AND STORMS OVER NORTHEAST TEXAS/NORTHWEST
LOUISIANA IS ASSOCIATED WITH ANOTHER DISTURBANCE ALOFT ROTATING
AROUND A BROAD UPPER TROUGH.  THERE IS SOME QUESTION WITH REGARD TO
IT MAKING IT INTO MY WESTERN ZONES...AS NEARLY ALL THE HIGH-RES
MODELS WEAKEN IT OVER NORTHERN LOUISIANA.  MY THINKING IS THIS IS
LIKELY DUE TO THE AIRMASS OVER NORTH CENTRAL AND NORTHEAST LOUISIANA
BEING "WORKED OVER" BY YESTERDAY AFTERNOON AND EVENING`S CONVECTION.
STILL...THE PROGRESSION OF THIS COMPLEX...OR AT LEAST ANY EASTWARD
PROPAGATING OUTFLOW BOUNDARY ASSOCIATED WITH IT...WILL CERTAINLY
CONTINUE TO BE MONITORED THROUGH THE AFTERNOON AS IT COULD
POTENTIALLY GET INTO MY LOUISIANA PARISHES LATER THIS AFTERNOON AND
EVENING IF IT INDEED HOLDS TOGETHER.

OVERALL SEVERE WEATHER PARAMETERS CURRENTLY LOOK LOW...SO I CAN`T
RULE OUT A FEW PULSE STRONG TO SEVERE STORMS THIS AFTERNOON.  DUE TO
THIS POTENTIAL BEING ON THE LOW-END OF THE SPECTRUM...I`LL NOT
MENTION  IT IN THE HWO.  THAT SAID...THE FEW STORMS THAT INDEED
REACH THAT STRONG TO SEVERE THRESHOLD WILL BE CAPABLE OF PRODUCING
40-60 MPH WIND GUSTS AND HAIL.  FREQUENT LIGHTNING AND A BRIEF HEAVY
DOWNPOUR WILL BE LIKELY WITH ALL OF TODAY`S STORMS.

THE BIGGEST CHANGE MADE TO TODAY`S FORECAST WILL BE TO HIGH
TEMPERATURES...WHERE THEY WERE INCREASED ACROSS THE BOARD BY A
COUPLE OF DEGREES.  THIS WAS PRIMARILY BASED UPON CURRENT HOURLY
TEMPERATURES RUNNING SOME 3-6 DEGREES ABOVE FORECASTED VALUES...EVEN
AT LOCALES WHERE CLOUD COVER WAS OBSERVED...AND PERSISTENCE OVER THE
PAST FEW AFTERNOONS.  THIS PUTS HIGHS THIS AFTERNOON TOPPING OUT IN
THE MID TO UPPER 80S.  THAT SAID...CLOUD COVER...CONVECTION...AND
ASSOCIATED OUTFLOW BOUNDARIES WILL BE THE GREAT EQUALIZERS IN
KEEPING TEMPERATURES IN CHECK. /19/

&&

.AVIATION...MORNING CLOUDS ARE CLEARING AND EXPECT MOSTLY VFR
CONDITIONS TODAY OUTSIDE OF THUNDERSTORMS. SHOWERS AND STORMS MOVING
THROUGH THE DELTA NOW AND COULD AFFECT KGLH/KGWO THROUGH THE
MORNING. ADDITIONAL STORMS EXPECTED TODAY WHICH COULD LIMIT
RESTRICTIONS TO BRIEF MVFR AND IFR CATEGORIES. COVERAGE EXPECTED TO
BE SCATTERED TO NUMEROUS. /28/

&&

.PREV DISCUSSION... /ISSUED 442 AM CDT SAT MAY 30 2015/

DISCUSSION...THROUGH SUNDAY NIGHT...IT STILL LOOKS AS IF A SLOW
MOVING TROUGH SET TO PROGRESS THROUGH THE LOWER MS VALLEY THIS
WEEKEND WILL MAKE FOR INTERMITTENTLY STORMY CONDITIONS IN MOST
LOCATIONS...POSSIBLY EVEN AT NIGHT. A LOBE OF ENERGY ROTATING THROUGH
THE BROAD TROUGH AXIS IS INSTIGATING A FAIR AMOUNT OF SHOWERS AND
STORMS JUST TO OUR NORTHWEST AS I WRITE. SOME OF THIS ACTIVITY WILL
LIKELY BUILD SOUTHEAST INTO THE ARKLAMISS DELTA THROUGH THE MORNING
WHILE OTHER AREAS REMAIN LARGELY DRY UNTIL AT LEAST MIDDAY. LOCATIONS
IN EASTERN AND SOUTHEASTERN MS SHOULD REMAIN VOID OF MUCH
THUNDERSTORM ACTIVITY THE LONGEST...ALLOWING THEM TO HEAT UP CLOSE TO
90 DEGREES AND BUILD ASSOCIATED INSTABILITY. IT IS IN THESE AREAS
SOUTHEAST OF THE NATCHEZ TRACE WHERE STRONGER STORMS WITH GUSTY WINDS
AND SMALL HAIL ARE MORE LIKELY THIS AFTERNOON. BUT EVEN WITH THIS
EXPECTATION...WIND SHEAR AND INSTABILITY INGREDIENTS SHOULD REMAIN
INSUFFICIENT FOR MORE THAN A FEW ISOLATED LOW-END SEVERE STORMS WHILE
TAME DCAPE AND LAPSE RATES ARE NOT VERY CONDUCIVE FOR MICROBURSTS
EITHER.

GOING INTO TONIGHT A GOOD DEAL OF THUNDERSTORMS SHOULD DIMINISH IN
THE EVENING INITIALLY...BUT MODEL CONSENSUS SUGGESTS CONVERGENCE
NEAR AN INCOMING WEAK SURFACE FRONT WILL PROBABLY TRIGGER SCATTERED
SHOWERS AND STORMS ALONG AND NORTHWEST OF THE NATCHEZ TRACE LATER IN
THE EVENING AND INTO THE OVERNIGHT. SOME HEAVY DOWNPOURS COULD
RESULT FROM THIS OVERNIGHT ACTIVITY ALTHOUGH SEVERE POTENTIAL LOOKS
QUITE MEAGER.

INTO SUNDAY THE SLOWLY PROGRESSIVE NATURE OF THE TROUGH SHOULD TEND
TO FOCUS THE BULK OF SHOWERS AND THUNDERSTORMS SOUTHEAST OF THE
ARKLAMISS DELTA (ESPECIALLY IN THE AFTERNOON). POTENTIAL FOR
SIGNIFICANT DESTABILIZATION EVEN IN SOUTHEAST MS LOOKS MORE LIMITED
THAN TODAY CONSIDERING MORE WIDESPREAD NATURE OF CLOUD COVER AND
MORNING TO MIDDAY SHOWERS AND STORMS. ONCE AGAIN A SEVERE STORM OR
TWO CANNOT BE RULED OUT AT THIS POINT CONSIDERING THERE WILL BE A
BIT OF ATMOSPHERIC SHEAR BUT THERE IS NOT ENOUGH GOING FOR THE SETUP
TO INCLUDE MENTION IN THE HWO. SUNDAY NIGHT SHOWERS AND STORMS MAY
TEND TO GET SEQUESTERED INTO SOUTHEAST SECTIONS OF THE REGION
QUICKLY IN THE EVENING WITH POTENTIAL FOR LINGERING OVERNIGHT
ACTIVITY LOWER THAN WILL BE THE CASE LATE TONIGHT.

IT WAS MENTIONED ABOVE THAT THE HWO WILL BE KEPT CLEAR OF SEVERE
THUNDERSTORM THREATS...BUT HEAVY RAIN THREATS WERE ALSO CONSIDERED
FOR INCLUSION AND DEEMED LACKING AS WELL. IT IS QUITE PLAUSIBLE
THROUGH THE WEEKEND A FEW ISOLATED SPOTS COULD PICK UP 2 TO 3 INCHES
OF RAINFALL BUT IT WILL LIKELY NOT COME IN A VERY SHORT SPAN OF
TIME. THIS EXPECTATION...IN CONSIDERATION WITH THE FACT OF THE
GROUND NOT BEING OVERLY SATURATED IN MOST AREAS...MAKES ME THINK
FLOODING PROBLEMS WILL BE GENERALLY AVOIDED. /BB/

MONDAY THROUGH FRIDAY...THE LONG RANGE FORECAST CONTINUES TO BE IN
FLUX AS MODEL GUIDANCE TRENDS TOWARD A MORE PROGRESSIVE SOLUTION
RESULTING IN A DRIER AND WARMER STRETCH OF WEATHER...A BIG CHANGE
FROM THE RECENT CONSENSUS FOR A MEANDERING CUT-OFF LOW THAT WAS
EXPECTED TO BRING RAINY WEATHER TO THE ARKLAMISS REGION.

TO START THE WORK WEEK...AN OPEN WAVE WILL CONTINUE TO SLOWLY PUSH
SOUTHEAST ACROSS THE LOWER MS VALLY REGION WITH MOISTURE CONVERGENCE
SETTING UP AHEAD OF THE TROUGH AXIS OVER ERN/SRN MS MONDAY AFTN.
ALTHOUGH SHEAR IS EXPECTED TO BE WEAK...THERE COULD BE SUBSTANTIAL
INSTABILITY SUPPORTIVE OF STRONG TO PERHAPS SEVERE STORMS DURING PEAK
HEATING. THEREAFTER...THE THREAT FOR HEAVY RAINFALL AND SEVERE
WEATHER WILL DROP OFF SIGNIFICANTLY FOR MID WEEK. THE GEFS DOES HAVE
SEVERAL MEMBERS CUTTING OFF SHORTWAVE ENERGY IN THE VICINITY OF THE
CENTRAL GULF COAST...BUT ITS MEAN LOW POSITION IS CONSIDERABLY
FARTHER EAST SUGGESTING THAT ASSOCIATED WARM ADVECTION AND LARGE
SCALE FORCING/PRECIP WILL FOCUS EAST OF THE FORECAST AREA. SO HAVE
CONTINUED THE TREND OF REDUCING POPS AND CONFINING THEM MORE TO
SOUTHEAST OF THE NATCHEZ TRACE.

BY THE END OF THE WEEK...THERE ARE SOME INDICATIONS THAT EASTERLY
FLOW NORTH OF A CLOSED LOW IN THE VICINITY OF SRN GA/FL WILL HELP
TO ADVECT DEEPER MOISTURE FAR ENOUGH WEST TO INCREASE POPS OVER
CNTRL/ERN MS. OTHERWISE...IT IS WORTH NOTING THAT WE HAVE INCREASED
HIGH TEMPERATURES A LITTLE FOR NEXT WEEK BASED ON LATEST TRENDS. /EC/

&&

.PRELIMINARY POINT TEMPS/POPS...
JACKSON       87  67  83  65 /  70  49  66  39
MERIDIAN      87  66  85  65 /  57  40  64  46
VICKSBURG     86  68  83  65 /  71  56  56  32
HATTIESBURG   89  67  86  67 /  50  40  60  44
NATCHEZ       85  68  82  66 /  67  53  59  37
GREENVILLE    86  68  81  64 /  61  51  42  22
GREENWOOD     85  67  82  64 /  66  55  48  27

&&

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

$$

19/28


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