116
FXUS64 KJAN 051936
AFDJAN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
236 PM CDT MON MAY 5 2025
..NEW DISCUSSION
DISCUSSION
ISSUED AT 208 PM CDT MON MAY 5 2025
TOMORROW THROUGH THE WEEKEND...
THE MAIN THREAT WILL BE HEAVY RAIN AND FLASH FLOODING TOMORROW, WITH
CONTINUOUS BOUTS OF DIURNALLY DRIVEN RAIN EXPECTED THROUGH THE
REST OF THE WEEK.
AN END TO THE PERIOD OF GENERALLY DRIER DAYS IS ON THE HORIZON
BEGINNING TOMORROW WITH THE CLOSED LOW CURRENTLY LOCATED IN THE
OHIO RIVER VALLEY MIGRATING EASTWARD AND AN ADDITIONAL CLOSED LOW,
CURRENTLY OVER THE SOUTHERN PLAINS, BEGINS TO MOVE OUR WAY. THE
APPROACHING LOW (SITUATED ON THE WESTERN FLANK OF AN UPPER LEVEL
"OMEGA BLOCK") WILL ALLOW FOR ROBUST CONVEYANCE OF WARM AND MOIST
AIR OUT AHEAD OF IT, RAISING LOW LEVEL DEW POINTS AND TEMPERATURES
UP TO 10F; PROVIDING 2IN PWATS AND IVT INTO THE 99TH PERCENTILE
THROUGH WEDNESDAY. A WARM FRONT SEPARATING LOWER TO MID 60S F
DEWPOINTS FROM DEWPOINTS ABOVE 70 F WILL ATTEMPT TO MOVE NORTHWARD
FROM ITS POSITION ALONG THE GULF COAST BY TOMORROW AFTERNOON AS
SOUTHERLY WARM ADVECTION INCREASES: THIS WILL SERVE AS A PRIMARY
FOCUSING MECHANISM FOR OUR PRECIPITATION THROUGHOUT THE WEEK.
THIS TEMPERATURE/MOISTURE FLUX GENERATED BY THE POWERFUL UPPER
LEVEL DISTURBANCE WILL ALSO TRIGGERING WIDESPREAD SHOWERS AND
THUNDERSTORMS THROUGH LOUISIANA AND SPREADING EASTWARD THROUGHOUT
THE AFTERNOON INTO THE MORNING. SHOWER AND STORM ACTIVITY WILL
SERVE TO IMPEDE THE NORTHWARD PROGRESS OF THE FRONT AND WILL
LIKELY RESULT IN THE BOUNDARY BECOMING STALLED SOMEWHERE SOUTH OF
I-20. THUNDERSTORM COVERAGE WILL INCREASE THROUGHOUT THE DAY AND
INTO THE NIGHT, POTENTIALLY ORGANIZING INTO AN MCS BY SUNSET THAT
COULD MOVE EASTWARD ALONG THE BOUNDARY, FURTHER RESULTING IN A
STALL OF THE BOUNDARY. CURRENT GUIDANCE HAS CONTINUED TO TREND
TOWARDS A WELL DEFINED AREA OF HEAVY RAIN (4-8IN/12HRS) LOCATED IN
OUR SOUTHWESTERN QUADRANT (WEST OF I- 55 & SOUTH OF I-20) AND
THIS SOLUTION APPEARS REASONABLE: WITH REPLENISHED GULF HEAT AND
HUMIDITY BEING PUSHED INTO THE STALLED BOUNDARY, TRAINING AND
STORM REGENERATION COULD RESULT IN A NARROW CORRIDOR OF VERY
INTENSE (2+"/HR) RAINFALL RATES OVER A PROLONG PERIOD/MULTIPLE
WAVES OF STORMS.
WHILE HEAVY RAIN AND FLASH FLOODING ARE THE HIGHEST CONFIDENCE
THREATS FOR THE TUESDAY-WEDNESDAY TIMEFRAME, THERE DOES EXIST A
POTENTIAL FOR SEVERE THUNDERSTORMS THROUGH THE SOUTHWESTERN PORTIONS
OF THE CWA TOMORROW. THE ATMOSPHERIC PROFILE SHOULD ALLOW FOR
HELICITY VALUES IN THE LOWEST 3 KM TO EXCEED 200 M^2/S^2 WITH SOME
OPPORTUNITY FOR VALUES ABOVE 400 M^2/S^2 SHOULD MESOSCALE UPSCALE
GROWTH OCCUR. CAPE VALUES REMAIN FAIRLY SUBDUED FOR EARLY MAY,
HOWEVER; GIVEN OUR FRONTALLY INDUCED MECHANICAL LIFTING THERE
SHOULD BE PLENTY OF LIFT THAT WILL NOT BE OVERLY RELIANT ON
THERMODYNAMIC INSTABILITY. WHILE THE COLUMN WILL BE GENERALLY
SATURATED, OCCASIONAL DRY AIR INTRUSION THROUGH THE MID LEVELS
COULD ADD A BIT OF EVAPORATIVE COOLING AND LOCALIZED ENHANCEMENT
OF CONVECTIVELY DRIVEN DOWN DRAFT WINDS. UPPER-LEVEL DIFLUENCE IS
ALSO FAIRLY STRONG. ALL THIS TOGETHER IN OUR SOUTHWESTERN ZONES
HAS PROVIDED US AMPLE REASONING TO SIGNAL A MARGINAL SEVERE THREAT
ACROSS THOSE AREAS. PRIMARY HAZARDS WILL BE DAMAGING WIND AND
HAIL PERHAPS UP TO QUARTER SIZE, BUT BUT A TORNADO OR TWO CAN'T BE
RULED OUT. ONCE A SAMPLING OF THE WEATHER PATTERN TAKES PLACE
TOMORROW AND DEPENDING ON HOW THESE DYNAMICS SHIFT THERE REMAINS A
POSSIBILITY OF GENERATING ANOTHER MARGINAL SEVERE THREAT FOR
WEDNESDAY, CONFIDENCE REMAINS LOW AT THIS POINT THAT ANOTHER
GRAPHIC WILL BE NEEDED.
WEDNESDAY NIGHT THROUGH THE WEEKEND...
THE FRONT IS EXPECTED STALL OUT THROUGH THE AREA AND WAVER NORTH TO
SOUTH THROUGHOUT THE REMAINDER OF THE PERIOD. MOISTURE LEVELS
WILL REMAIN ELEVATED THROUGH THE WEEKEND AND IN CONJUNCTION WITH
A FEW WEAK UPPER LEVEL IMPULSES TRANSITING OVER THE AFOREMENTIONED
FRONT OUR RAIN CHANCES WILL REMAIN ABOVE 25% EACH DAY THROUGH
SATURDAY MORNING. RAIN RATES AND STORM COVERAGE WITH THIS
ACTIVITY LOOK TO BE FAR MORE MANAGEABLE FOR THE REST OF THE
WEEK WITH MOST AREAS RECEIVING LESS THAN AN ADDITION INCH LATE
FRIDAY THROUGH THE WEEKEND. SHOWER/THUNDERSTORM COVERAGE WILL BE
PRIMARILY DIURNALLY DRIVEN, REACHING A CRESCENDO OF WIDESPREAD
SHOWERS AND EMBEDDED THUNDERSTORMS BY MID-AFTERNOON, WINDING DOWN
TO SCATTERED SHOWERS WITH AN ISOLATED THUNDERSTORM OR TWO BY LATE
EVENING.
THIS WEEKEND COUNTIES/PARISHES ALONG AND WEST OF THE MISSISSIPPI
RIVER, COULD SEE A BREAK IN THE RAIN BUT EXPECT A LINGERING SHOWER
OR TWO. LONG TERM GUIDANCE INDICATES IT MAY BE A WEEK OR MORE
BEFORE WE SEE A BREAK IN THIS PATTERN AND ISOLATED TO SCATTERED DIURNAL
RAIN CHANCES ARE LIKELY THROUGH THE REMAINDER OF THE FORECAST
PERIOD./OAJ/86/
AVIATION
(18Z TAFS)
ISSUED AT 1229 PM CDT MON MAY 5 2025
VFR CONDITIONS WILL PREVAIL ACROSS ALL SITES THROUGH 16Z WHEN
CEILINGS WILL LOWER TO MVFR FOR HEZ AS STRATUS BUILDS IN FROM THE
SOUTHWEST. WINDS WILL REMAIN LIGHT THROUGH THE PERIOD. /86/
PRELIMINARY POINT TEMPS/POPS
JACKSON 58 79 63 79 / 10 60 100 80
MERIDIAN 54 79 60 77 / 0 30 90 90
VICKSBURG 58 77 64 80 / 10 80 100 70
HATTIESBURG 58 81 66 81 / 10 50 90 90
NATCHEZ 60 77 67 78 / 20 90 90 70
GREENVILLE 58 78 63 76 / 10 60 100 60
GREENWOOD 57 79 62 78 / 0 40 100 70
JAN WATCHES/WARNINGS/ADVISORIES
MS...FLOOD WATCH FROM TUESDAY AFTERNOON THROUGH THURSDAY EVENING FOR
MSZ040>043-047>066-072>074.
LA...FLOOD WATCH FROM TUESDAY AFTERNOON THROUGH THURSDAY EVENING FOR
LAZ007>009-015-016-023>026.
AR...FLOOD WATCH FROM TUESDAY AFTERNOON THROUGH THURSDAY EVENING FOR
ARZ074-075.
OAJ/OAJ/LP
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