Area Forecast Discussion
Issued by NWS Jackson, MS

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000
FXUS64 KJAN 061551 AAA
AFDJAN

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON MS
1051 AM CDT MON JUL 6 2015

.UPDATE...
MORNING 12Z REGIONAL RAOBS INDICATE STEEP 0-3KM LAPSE RATES AND GOOD
VERTICAL TOTALS APPROACHING 27-30 DEG C. WITH SFC MOISTURE/THETA-E
SLOWLY CREEPING BACK IN...DEWPOINTS GETTING INTO THE LOW 70S AND H3
UPPER JET/DIFFLUENCE MOVING IN FROM THE W...MODIFIED 12Z KJAN
SOUNDING INDICATES FAVORABLE MICROBURST ENVIRONMENT AND SOME
POTENTIAL THIS AFTERNOON FOR A FEW STRONG/SEVERE STORMS...MAINLY E
OF A LINE FROM NATCHEZ TO GRENADA. WITH BEST VERTICAL TOTALS PER
KLCH/KLIX SOUNDINGS AND HI-RES ARW/NMM AND HRRR INDICATING
DEVELOPMENT IN E/NE LA AND MOVING NE...ADJUSTED HWO/GRAPHICS TO
REFLECT THIS. TIMING LOOKS MAINLY IN THE MID AFTERNOON FOR
DEVELOPMENT BUT LEFT SOME POPS A FEW HOURS AFTER 00Z TO ACCOUNT FOR
LINGERING STORMS. ADJUSTED POPS/QPF WESTWARD DUE TO HI-RES GUIDANCE
TRENDS. ADJUSTED SKY GRIDS TO ACCOUNT FOR CONVECTION IN REGION
PREVIOUSLY MENTIONED THIS AFTERNOON. HIGHS LOOK GOOD OVERALL IN THE
LOW 90S. REST OF THE FORECAST IS ON TRACK. /DC/

&&

.AVIATION...MAIN ISSUE IN THE SHORT TERM IS IFR CIGS AT KGLH AND
KGWO. THESE SHOULD LIFT OVER THE NEXT FEW HOURS. OTHERWISE...WILL
HAVE TO WATCH FOR SHRA/TSRA DEVELOPMENT THIS AFTERNOON. CURRENT
THINKING IS THAT ACTIVITY WILL BE SCATTERED ENOUGH TO NOT INCLUDE IN
THE TAFS. WILL NEED TO MONITOR SITES FOR LOCAL IMPACTS THIS
AFTERNOON. /SW/

&&

.PREV DISCUSSION... /ISSUED 451 AM CDT MON JUL 6 2015/

DISCUSSION...

TODAY THROUGH TUESDAY NIGHT...IT HAS BEEN A MUCH QUIETER NIGHT THAN
PREVIOUSLY ACROSS THE ARKLAMISS REGION. CURRENT SATELLITE AND
ANALYSIS SHOWS DRIER AIR MOVING SOUTH INTO THE REGION WHICH IS
REFLECTED BY THE MID 60 DEWPOINTS BEING OBSERVED. THIS IS ABOUT 1-3
DEGREES DRIER THAN THIS TIME YESTERDAY MORNING. SFC ANALYSIS ALSO
SHOWS THAT THE SFC HIGH PRESSURE IS RESIDING OVER THE REGION...AND
LIKELY HAVING SOME CONTROL OVER OUR WEATHER.

TODAY SHOULD BE MUCH DRIER AIR THAN THE PREVIOUS FEW DAYS AS THE
UPPER TROUGH THAT HAD BEEN INFLUENCING OUR WEATHER AND STORM
DEVELOPMENT OVER THE WEEKEND HAS PUSHED OFF TO THE EAST. WHILE DURING
THAT TIME MODELS(PARTICULARLY THE HI-RES SUITE) HAD NOT BEEN
DEPICTING THE EXPECTED WEATHER SCENARIO THE BEST...THEY WERE A LOT
WETTER/MORE ACTIVE THAN WHAT IS BEING SHOWN FOR TODAY. THIS LENDS
SOME CONFIDENCE THAT COVERAGE TODAY SHOULD BE A BIT LOWER. IN
FACT...ALL HI-RES GUIDANCE AND THE SSEO INDICATE THE BEST LOCATION
FOR ANY STORM DEVELOPMENT WOULD BE ACROSS EASTERN MISSISSIPPI...
PARTICULARLY ACROSS THE GOLDEN TRIANGLE REGION. THEREFORE...HAVE GONE
WITH LOWER POPS THAN PREVIOUSLY FORECAST BUT MORE CONFINED TO THE
EASTERN/NORTHEASTERN PORTION OF THE CWA. THIS ACTIVITY SHOULD WAIT
UNTIL AFTERNOON TO DEVELOP AS CURRENT DRY AIR SHOULD BE REPLACED BY A
BIT MOISTER AIR AS DEPICTED BY AN INCREASE IN THETA-E VALUES AND PW
VALUES(EXCEEDING 1.5 INCHES BY AFTERNOON). IN TERMS OF SEVERE
POTENTIAL...WHILE COVERAGE SHOULD NOT BE GREAT TODAY THERE DOES
REMAIN SOME LIMITED POTENTIAL FOR A STRONG TO SEVERE STORM GIVEN
VERTICAL TOTALS AROUND 27-29C AND CAPE NEARING 3000 J/KG AMONG OTHER
PARAMETERS. HAVE KEPT THE LIMITED RISK IN THE HWO/GRAPHICS BUT WILL
SHRINK THE AREA TO BETTER FIT WHERE STORMS MAY ACTUALLY OCCUR.
OUTSIDE OF THIS AREA...THERE IS A BIT MORE OF A CONDITIONAL RISK AS
PARAMETERS STILL LOOK GOOD FOR A STRONG STORM BUT CONFIDENCE IN
SEEING ANY CONVECTION IS LOWER.

AFTER TODAY RAIN CHANCES START TO DECREASE AS THE UPPER RIDGE BEGINS
TO BUILD OVER THE REGION. THIS WILL KEEP A STALLED FRONT AND
ASSOCIATED RAIN NORTH OF THE REGION. HOWEVER...TEMPERATURES WILL
BEGIN TO GET WARMER. HIGHS BOTH TODAY AND TUESDAY WILL BE IN THE 90S
WITH OVERNIGHT LOWS IN THE 70S. /JC/

WEDNESDAY THROUGH SUNDAY...

INCREASING HEAT AND SMALL RAIN CHANCES WILL BEST DESCRIBE THE LONG
RANGE FORECAST. NWP GUIDANCE CONSENSUS IS FOR THE SUBTROPICAL
RIDGE TO EXPAND WESTWARD AND INTENSIFY OVER THE ARKLAMISS REGION AS
WE GO FROM MID TO LATE WEEK AND THROUGH THE WEEKEND. FOR
WEDNESDAY...HAVE STUCK WITH THE LOW GUIDANCE POPS GIVEN RELATIVE
LACK OF DEEP LAYER MOISTURE (PRECIPITABLE WATER NEAR/LESS THAN 1.5
INCHES FOR MUCH OF THE AREA)/ WELL-MIXED RELATIVELY DRY BOUNDARY
LAYER LAYER AND ANTICYCLONIC FLOW WHICH WILL LIMIT MOISTURE
CONVERGENCE. WITH THAT SAID...MID LEVEL TEMPERATURES WILL BE COOL
FOR A SOLID RIDGE IN MID JULY (H500 TEMPS ~ -8 DEG C) AND COMBINED
WITH INCREASING LOW LEVEL HEAT SHOULD RESULT RESULT IN STEEP LAPSE
RATES...SO STORMS THAT MANAGE TO DEVELOP WOULD HAVE A CHANCE TO
BECOME STRONG/SEVERE.

MOISTURE AND CONVECTIVE COVERAGE COULD INCREASE SLIGHTLY BEYOND
WEDNESDAY...BUT EXPECT THE SAME GENERAL PATTERN TO KEEP TSTM
COVERAGE LIMITED. WITH HIGH TEMPERATURES STARTING TO REACH THE MID
90S...IT LOOKS LIKE HEAT INDICES IN THE 100-105 F RANGE WILL BE MORE
COMMON...ESPECIALLY OVER THE DELTA REGION. THE HEAT IS EXPECTED TO
PEAK THIS WEEKEND AND POSSIBLY PERSIST INTO EARLY NEXT WEEK. /EC/

&&

.PRELIMINARY POINT TEMPS/POPS...
JACKSON       91  72  92  73 /  22  16   8   8
MERIDIAN      90  70  91  70 /  30  16   5   3
VICKSBURG     91  72  92  73 /  18  12   7   8
HATTIESBURG   93  73  92  73 /  21  16   6  10
NATCHEZ       89  74  91  74 /  16  12   9   9
GREENVILLE    90  74  92  74 /  21  12   3   8
GREENWOOD     88  70  90  73 /  22  16   6   6

&&

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

$$

DC/SW/JC/EC


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