047
FXUS64 KMEG 180523
AFDMEG
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
1123 PM CST TUE DEC 17 2024
..NEW AVIATION
UPDATE
ISSUED AT 1051 PM CST TUE DEC 17 2024
WARM AIR ADVECTION SHOWERS AND A FEW THUNDERSTORMS HAVE OCCURRED
FOR MUCH OF THE EVENING, FOCUSED TO THE NORTH OF A SLOWLY-
ADVANCING WARM FRONT. THE LATEST SURFACE ANALYSIS PLACES A 1018MB
LOW NORTH OF THE ARKLATEX WITH A WARM FRONT EXTENDING NORTHEAST
THROUGH CENTRAL ARKANSAS AND INTO WEST TENNESSEE ALONG THE I-40
CORRIDOR. THIS WARM FRONT WILL SLOWLY LIFT NORTH OVER THE NEXT
COUPLE OF HOURS AND SERVE AS THE FOCUS FOR MORE CONVECTION
OVERNIGHT.
A LOOSELY ORGANIZED LINE OF STORMS WILL FORM JUST AHEAD OF AN
ADVANCING COLD FRONT AND POSE A MARGINAL RISK FOR SEVERE
THUNDERSTORMS, MAINLY BETWEEN 3 AND 9 AM. THE THERMODYNAMIC
ENVIRONMENT APPEARS TO BE QUITE SIMILAR TO LAST EVENING, WITH
SLIGHTLY LESS INSTABILITY. WITH WELL CURVED HODOGRAPHS, ABOUT 700
J/KG OF MUCAPE, 30 TO 40 KNOTS OF BULK SHEAR, AND WEAK LOW LEVEL
LAPSE RATES, STORM MODE WILL BE MAINLY CONFINED TO MULTICELLS AND
A FEW BOWING STRUCTURES WITHIN THE ADVANCING LINE. LOW LEVEL
HELICITY FIELDS OF 200 M2/S2 OR SRH COULD SUPPORT A TORNADO WITH
ANY CELLS THAT FORM AHEAD OF THE LINE, ALBEIT A WEAK ONE. THE MAIN
THREAT STILL APPEARS TO BE HEAVY RAINFALL, WHICH COULD LEAD TO
INSTANCES OF FLASH FLOODING OR MINOR RIVER FLOODING.
THE CURRENT FORECAST IS ON TRACK AND THE FLASH FLOOD WATCH IS IN
GOOD SHAPE.
AC3
SYNOPSIS
ISSUED AT 314 PM CST TUE DEC 17 2024
A COLD FRONT WILL PUSH THROUGH THE MID-SOUTH WITH SHOWERS AND
THUNDERSTORMS THROUGH WEDNESDAY MORNING. A FEW SEVERE STORMS AND
LOCALLY HEAVY RAINFALL ARE POSSIBLE. DRIER AND GRADUALLY COLDER
AIR WILL PREVAIL FOR THE END OF THE WEEK INTO THE WEEKEND.
DISCUSSION
(THIS EVENING THROUGH NEXT MONDAY)
ISSUED AT 314 PM CST TUE DEC 17 2024
A WARM FRONT STRETCHED FROM EAST TN ACROSS EXTREME NORTH MS INTO THE
RED RIVER VALLEY AT 21Z. THE FRONT IS STARTING TO LIFT NORTH IN
RESPONSE TO A MID LEVEL TROUGH PUSHING INTO THE PLAINS. SOME
PATCHY FOG IS DEVELOPING NORTH OF THE FRONT AND THIS COULD OCCUR
THROUGHOUT THE NIGHT, ESPECIALLY ACROSS NE AR AND THE MO BOOTHEEL.
AS WARM AIR ADVECTION INCREASES, EXPECT SHOWERS TO CONTINUE TO
POP UP ACROSS THE AREA THIS EVENING.
AS THE MID LEVEL TROUGH APPROACHES TONIGHT, SURFACE LOW PRESSURE
WILL DEVELOP AND TRACK ACROSS SOUTHERN MO INTO WESTERN KY WHILE A
TRAILING COLD FRONT PUSHES INTO THE MID-SOUTH AFTER MIDNIGHT.
SHOWER AND THUNDERSTORM COVERAGE WILL REALLY RAMP UP AFTER MIDNIGHT
ACROSS NE AR AND THE MO BOOTHEEL AND SPREAD SLOWLY SOUTHEAST
OVERNIGHT INTO WEDNESDAY MORNING. THE LATEST CAMS ARE COMING IN A
LITTLE WETTER WITH FORECAST AMOUNTS OF 1-3 INCHES. LOCALLY HIGHER
AMOUNTS ARE POSSIBLE AS THE ORIENTATION OF THE COLD FRONT COULD LEAD
TO SOME TRAINING AND SATURATED GROUND WILL PROMOTE RUNOFF. A FLASH
FLOOD WATCH HAS BEEN ISSUED FOR MUCH OF THE NORTHERN HALF OF THE
MID-SOUTH FROM MIDNIGHT TONIGHT UNTIL NOON WEDNESDAY. THERE IS
ALSO A MARGINAL RISK OF SEVERE WEATHER ALONG THE I-40 CORRIDOR
LATER TONIGHT INTO WEDNESDAY MORNING AS MUCAPES CLIMB TO 500-1000
J/KG AHEAD OF THE FRONT. MARGINAL 0-6 KM BULK SHEAR VALUES AT
30-40 KTS COULD SUPPORT FEW SEVERE STORMS WITH DAMAGING WINDS AND
PERHAPS SOME LARGE HAIL. SURFACE BASED INSTABILITY WILL BE
MARGINAL WITH LESS THAN 250 J/KG. HOWEVER, SOME CAMS HAVE A LITTLE
MORE SB INSTABILITY SO CANNOT RULE OUT A QUICK SPIN UP THANKS TO
0-1KM HELICITY VALUES OF 200 M2/S2 AND SOMEWHAT SUPPORTIVE
HODOGRAPHS. TIMING FOR SEVERE WEATHER WILL RANGE FROM 2 AM TONIGHT
TO 10 AM WEDNESDAY.
SURFACE LOW PRESSURE WILL QUICKLY TRACK ACROSS KY DURING WEDNESDAY
MORNING AND THE COLD FRONT WILL EXIT NE MS BY NOON WITH SOME LEFT
OVER POST FRONTAL RAIN. COOL HIGH PRESSURE WILL BUILD IN DURING THE
AFTERNOON WITH SOME CLEARING. TEMPS WILL GRADUALLY COOL UNDER BRISK
NW WINDS. TEMPS WILL FALL INTO THE 30S WEDNESDAY NIGHT AND HIGHS ON
THURSDAY WILL RANGE FROM THE UPPER 40S TO MID 50S. A REINFORCING
COLD FRONT WILL SWEEP THROUGH THURSDAY NIGHT USHERING IN MUCH COOLER
AIR FOR THE END OF THE WEEK THROUGH THE WEEKEND WITH HIGHS IN THE
40S AND LOWS IN THE 20S.
A MORE ZONAL PATTERN DEVELOPS EARLY NEXT WEEK WITH SOMEWHAT MILDER
TEMPS RETURNING ALONG WITH PRECIP CHANCES BY TUESDAY.
AVIATION
(06Z TAFS)
ISSUED AT 1114 PM CST TUE DEC 17 2024
RAIN SHOWERS WILL CONTINUE TO MOVE ACROSS NORTHERN SECTIONS OF THE
MID-SOUTH FOR THE NEXT COUPLE OF HOURS. SHOWERS AND THUNDERSTORMS
WILL SWEEP ACROSS THE REGION AHEAD OF A COLD FRONT STARTING EARLY
WEDNESDAY MORNING AND CONTINUING THROUGH MUCH OF THE DAY. CEILINGS
WILL START OUT MAINLY AT MVFR BUT WILL LOWER TO IFR/LIFR AS THE
COLD FRONT APPROACHES. WINDS WILL BE FROM THE SOUTH AT 5 TO 10
KNOTS AHEAD OF THE FRONT. BEHIND THE FRONT, WINDS WILL BE NORTHWEST
AROUND 10 KNOTS.
MEG WATCHES/WARNINGS/ADVISORIES
AR...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR ARZ026>028-035-036-048-
049.
MO...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR MOZ113-115.
MS...NONE.
TN...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR TNZ001>004-019>022-
048>055-088>090.
PUBLIC FORECAST...SJM
AVIATION...ARS
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