Area Forecast Discussion
Issued by NWS Memphis, TN

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FXUS64 KMEG 261149 AAA
AFDMEG

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MEMPHIS TN
649 AM CDT TUE MAY 26 2015

.UPDATE...
UPDATED FOR 12Z AVIATION DISCUSSION BELOW.

&&

.PREV DISCUSSION... /ISSUED 426 AM CDT TUE MAY 26 2015/

DISCUSSION...WATER VAPOR SATELLITE/WSR-88D VAD WIND PROFILES
INDICATE A MESOSCALE CONVECTIVE SYSTEM /MCS/ OVER THE COASTAL
PLAIN OF TEXAS...LOUISIANA AND SOUTHERN MISSISSIPPI. THIS MCS HAS
BEEN WEAKENING AND IS SHOWING SIGNS OF TRANSITIONING INTO A
MESOSCALE CONVECTIVE VORTEX AS BETTER FORCING IS GRADUALLY MOVING
AWAY FROM THE LOWER MISSISSIPPI VALLEY. CONVECTIVE ACTIVITY
OVERNIGHT HAS BEEN UNIMPRESSIVE ACROSS THE MID SOUTH WITH NO
THUNDER BEING REPORTED AND A CONTINUED WEAKENING TREND. TEMPERATURES
AS OF 4 AM CDT ARE IN THE LOWER TO MIDDLE 70S AT MOST LOCATIONS
EXCEPT FOR MIDDLE TO UPPER 60S ALONG THE TENNESSEE RIVER.

SHOWERS ASSOCIATED WITH LAST NIGHT/S MCS OVER LOCATIONS EAST OF
THE MISSISSIPPI RIVER WILL CONTINUE TO PUSH THROUGH THE AREA THIS
MORNING. SHORT TERM MODELS HAD DIFFICULTY HANDLING THE OVERNIGHT
CONVECTIVE ACTIVITY AND SUBSEQUENTLY REDUCED RAIN CHANCES TODAY
AS UPPER LEVEL SUPPORT WEAKENS ACROSS THE MID SOUTH. A POTENTIAL
STILL EXISTS FOR SHOWERS AND THUNDERSTORMS TO RE-DEVELOP THIS
AFTERNOON COINCIDENT WITH CONVECTIVE TEMPERATURES BEING REACHED IF
THE ATMOSPHERE CAN RECOVER FROM THE STABILIZING EFFECTS OF THE
OVERNIGHT ACTIVITY. THE THREAT FOR WIDESPREAD HEAVY RAINFALL AND
SUBSEQUENT FLASH FLOODING HAS DIMINISHED. CONSEQUENTLY...DECIDED
TO CANCEL FLASH FLOOD WATCH AS THE HEAVY RAINFALL THREAT WILL BE
LOCALIZED AT BEST. A CONDITIONAL THREAT MAY STILL EXIST FOR A
STRONG TO PERHAPS ISOLATED SEVERE THUNDERSTORM WITH DAMAGING WINDS
AND LOCALIZED HEAVY RAINFALL POSSIBLE AS PRECIPITABLE WATER VALUES
STILL ARE APPROACHING 2 INCHES.

MODELS INDICATE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL PERSIST
ACROSS THE MID SOUTH THIS WEEK AS A SERIES OF MID LEVEL SHORTWAVES
MOVE ACROSS THE LOWER MISSISSIPPI VALLEY. CHANCE POPS SEEM
REASONABLE THROUGH THE PERIOD AS FORCING WILL BE DEPENDENT ON
DAYTIME INSTABILITY AS OVERALL FORCING FROM SHORTWAVE TROUGHS WILL
REMAIN SUBTLE AT BEST. ALSO...A CONDITIONAL THREAT MAY STILL
EXIST FOR A FEW STRONG TO PERHAPS ISOLATED SEVERE THUNDERSTORMS
DURING THIS TIME FRAME WITH DAMAGING WINDS AND LOCALIZED HEAVY
RAINFALL POSSIBLE AS THREATS.

LONG TERM MODELS INDICATE AN UPPER LEVEL TROUGH AND ASSOCIATED
COLD FRONT WILL MOVE THROUGH THE LOWER MISSISSIPPI VALLEY FOR THE
LATTER HALF OF THE UPCOMING WEEKEND INTO EARLY NEXT
WEEK...PROVIDING A BETTER FOCUS FOR SHOWER AND THUNDERSTORM
DEVELOPMENT. HIGH TEMPERATURES THIS WEEK WILL BE MAINLY IN THE
80S WITH LOWS IN THE 60S TO LOWER 70S.

CJC

&&

.AVIATION...
12Z TAFS

SHRA SHOULD EXIT MKL/TUP AREAS THROUGH 15Z. MVFR CIGS WILL LIKELY
PREVAIL IN THE WAKE OF THE SHOWERS...UNTIL DAYTIME HEATING
EFFECTIVELY RAISES CLOUD BASES OR SCATTERS OUT THE LOWER LAYERS.

HUMID AIRMASS REMAINS TONIGHT...WITH A SOUTHERLY LOW LEVEL JET
OVERLYING A MOIST LOW LEVEL INVERSION. WITH LIMITED TSRA/SHRA
OVER THE SOUTHERN PLAINS...MID/HIGH CLOUDS MAY BE MORE LIMITED
THAN IN PREVIOUS DAYS. THIS MAY ALLOW FOR STRONGER RADIATIONAL
COOLING AND GREATER IFR POTENTIAL TOWARD 27/12Z.

PWB

&&

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

$$


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