Area Forecast Discussion
Issued by NWS Memphis, TN

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FXUS64 KMEG 210528
AFDMEG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
1228 AM CDT MON APR 21 2014

.UPDATE...
UPDATED FOR 06Z AVIATION DISCUSSION.

&&

.PREV DISCUSSION... /ISSUED 937 PM CDT SUN APR 20 2014/

UPDATE...EVENING UPDATE.

AS OF 9PM...TEMPERATURES ARE GENERALLY IN THE 60S UNDER MOSTLY CLEAR
SKIES WITH A LIGHT SOUTHERLY WIND. TEMPERATURES WILL CONTINUE TO
FALL INTO THE LOWER 50S PREDOMINANTLY EAST OF THE MISSISSIPPI
RIVER...WITH MID TO UPPER 50S EXPECTED WEST OF THE RIVER DUE TO
INCREASING CLOUD COVER AHEAD OF AN APPROACHING LONGWAVE TROUGH.

LATEST GOES-R WATER VAPOR IMAGERY SHOWS A POSITIVELY TILTED LONGWAVE
TROUGH DIGGING ACROSS OKLAHOMA AND KANSAS...RESULTING IN NUMEROUS
SHOWERS AND THUNDERSTORMS THIS EVENING. THIS SYSTEM WILL CONTINUE
TO SLOWLY PROGRESS EASTWARD OVERNIGHT AND ARRIVE IN THE LOWER
MISSISSIPPI VALLEY BY EARLY TOMORROW AFTERNOON. RAIN CHANCES WILL
MOST LIKELY HOLD OFF UNTIL LATE TOMORROW MORNING FOR NORTHEAST
ARKANSAS...AND SPREAD ACROSS THE REST OF THE MID-SOUTH BY LATE
AFTERNOON INTO THE EVENING HOURS.

FORECAST IS IN GOOD SHAPE AND NO CHANGES ARE NEEDED.

AC3

&&

.PREV DISCUSSION... /ISSUED 247 PM CDT SUN APR 20 2014/

DISCUSSION...SURFACE ANALYSIS PLACES A RIDGE OF HIGH PRESSURE
STRETCHING FROM NEW ENGLAND BACK THROUGH THE LOWER MISSISSIPPI
VALLEY THIS AFTERNOON. VISIBLE/WATER VAPOR SATELLITE TRENDS
INDICATE SHORTWAVE TROUGH EMBEDDED WITHIN SOUTHWEST FLOW ALOFT
MOVING ACROSS THE CENTRAL AND SOUTHERN PLAINS WITH SHORTWAVE
RIDGING STILL IN PLACE ACROSS THE LOWER MISSISSIPPI. THIS IS
RESULTING IN SOME CIRRUS MOVING ACROSS THE MID SOUTH AND PRODUCING
MOSTLY SUNNY SKIES. AS OF 2 PM CDT...TEMPERATURES ACROSS THE FORECAST
AREA ARE IN THE UPPER 70S TO AROUND 80 DEGREES. SHOWER AND
THUNDERSTORM POTENTIAL MAINLY MONDAY INTO TUESDAY AND AGAIN FOR
LATE THIS WEEK INTO THE UPCOMING WEEKEND ARE THE PRIMARY
CHALLENGES IN THIS AFTERNOON/S FORECAST.

SHORT TERM...(TONIGHT THROUGH WEDNESDAY)...SURFACE AND UPPER
LEVEL RIDGING WILL GRADUALLY BEGIN TO WEAKEN LATER TONIGHT AS THE
UPPER LEVEL RIDGE AXIS TRANSITIONS EAST AND A POSITIVELY TILTED
UPPER LEVEL TROUGH AXIS MOVES ACROSS THE LOWER MISSISSIPPI VALLEY.
LATEST 12Z WRF/GFS MODELS INDICATE A MAJORITY OF THE QPF ARRIVING
MAINLY MONDAY NIGHT. HAVE BACKED OFF ON POPS LATE TONIGHT ACROSS PORTIONS
OF EAST/NORTHEAST ARKANSAS AS LATEST SHORT TERM MODEL SOUNDINGS
INDICATE A CAPPING INVERSION AND SOMEWHAT DRY AIR ALOFT WILL HAVE
TO BE OVERCOME INITIALLY ACROSS THE AREA. CHANCES FOR SHOWERS AND
THUNDERSTORMS WILL BE BEST ACROSS AREAS ALONG AND WEST OF THE
MISSISSIPPI RIVER ON MONDAY. SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO SPREAD ACROSS THE ENTIRE FORECAST AREA MONDAY NIGHT
AND GRADUALLY TAPER OFF TO AREAS SOUTH OF I-40 ON TUESDAY. HIGH
PRESSURE WILL BUILD TUESDAY NIGHT INTO WEDNESDAY ACROSS THE MID
SOUTH. TEMPERATURES THROUGH THE PERIOD WILL PREDOMINANTLY BE IN
THE 70S WITH LOWS IN THE 50S AND 60S THROUGH MONDAY NIGHT AND
40S/50S TUESDAY NIGHT.

LONG TERM...(THURSDAY THROUGH SUNDAY)...12Z GFS/ECMWF LONG TERM
MODELS INDICATE A RIDGE OF HIGH PRESSURE WILL GRADUALLY BREAK DOWN
ACROSS THE MID SOUTH ON THURSDAY AS A WEAKENING COLD FRONT DROPS INTO THE
LOWER MISSISSIPPI VALLEY AND BECOMES NEARLY QUASI-STATIONARY AS IT
BECOMES NEARLY PARALLEL TO UPPER LEVEL FLOW ALOFT. THIS PATTERN
WOULD SUPPORT THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS EACH DAY INTO
THE UPCOMING WEEKEND IF THESE MODEL TRENDS PERSIST IN SUBSEQUENT
FORECASTS. WILL KEEP RAIN CHANCES ON THE LOW END FOR THE TIME
BEING UNTIL TIMING OF UPPER LEVEL SHORTWAVES CAN BE BETTER
DETERMINED IN LATER MODEL RUNS.

CJC

&&

.AVIATION...
06Z TAF CYCLE

VFR CONDITIONS ARE EXPECTED MOST OF NEXT 24 HOURS. SOME SHOWERS AND
THUNDERSTORMS MAY PRODUCE MVFR CONDITIONS IN SOME LOCATIONS.  TIMING
OF PRECIPITATION IS STILL UNCERTAIN. CONVECTION WILL BE SCATTERED
IN NATURE WITH THE BEST TIME FRAME OF THUNDERSTORMS IN TAFS. FOR
MEM IT WOULD EARLY EVENING.

TLSJR

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$







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