Area Forecast Discussion
Issued by NWS Memphis, TN

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000
FXUS64 KMEG 130823
AFDMEG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
323 AM CDT SUN JUL 13 2014

.DISCUSSION...

AN UPPER LEVEL RIDGE OF HIGH PRESSURE WILL EXTEND ACROSS THE MID
SOUTH TODAY. THE RIDGE WILL REMAIN WEAKEST ACROSS NORTHEAST
MISSISSIPPI THIS AFTERNOON WHERE DEEPER MOISTURE AND STRONG
HEATING SHOULD LEAD TO ISOLATED AFTERNOON AND EARLY EVENING
SHOWERS AND THUNDERSTORMS. ELSEWHERE...COVERAGE SHOULD AGAIN
REMAIN TOO LOW TO INCLUDE MENTION IN THE FORECAST. TEMPERATURES
SHOULD NUDGE UP A DEGREE OR TWO HIGHER THAN YESTERDAY...BUT STILL
REMAIN BELOW LATEST GUIDANCE NUMBERS. THIS SHOULD BE A RESULT OF A
WEAKER THAN MODEL ADVERTISED UPPER RIDGE AND ANTECEDENT MOIST
GROUND CONDITIONS THAT STILL REMAIN IN MOST AREAS. THE
COMBINATION OF AFTERNOON HIGH TEMPERATURES IN THE LOWER TO MIDDLE
90S COMBINED WITH DEWPOINTS IN THE LOWER 70S WILL LIKELY PUSH HEAT
INDEX VALUES TO BETWEEN 100-104 DEGREES DURING PEAK HEATING.

THE UPPER RIDGE SHOULD BEGIN TO BREAK DOWN TONIGHT AS A LARGE
SCALE UPPER TROUGH CONTINUES TO DIG ACROSS THE NORTHERN PLAINS AND
GREAT LAKES REGION. THIS SHOULD PUSH A COLD FRONT NOW OVER THE CENTRAL
PLAINS INTO THE MIDDLE MISSISSIPPI VALLEY REGION SOUTHWARD TO A
POSITION NEAR OUR NORTHERN CWA BORDER BY LATE TONIGHT WHERE IT
SHOULD STALL OUT. SCATTERED SHOWERS AND THUNDERSTORMS WILL LIKELY
DEVELOP AHEAD OF THE FRONT TODAY ACROSS THE CENTRAL U.S. AND
ADVANCE SOUTHWARD INTO FAR NORTHERN SECTIONS OF THE MID SOUTH
AFTER MIDNIGHT TONIGHT.

MID LEVEL HEIGHTS WILL CONTINUE TO FALL ON MONDAY AS THE UPPER
TROUGH ADVANCES FURTHER SOUTH AND EAST. THIS COMBINED WITH DAYTIME
HEATING AND A VERY MOIST LOW LEVEL ATMOSPHERE SHOULD ALLOW THE
ATMOSPHERE TO BECOME MODERATE TO STRONGLY UNSTABLE BY MONDAY
AFTERNOON OVER MUCH OF THE MID SOUTH. SBCAPES GREATER THAN 2500
J/KG ALONG WITH LI/S OF -6C OR LESS SHOULD EXIST. NUMEROUS SHOWERS
AND THUNDERSTORMS WILL DEVELOP ALONG AND NORTH OF INTERSTATE
40...WITH SCATTERED COVERAGE ACROSS SOUTHERN SECTIONS. DEEP LAYER
SHEAR SHOULD INCREASE TO AROUND 30 KTS...WHICH WHEN COMBINED WITH
THE INSTABILITY...SHOULD ALLOW FOR STORMS TO ORGANIZE INTO
MULTICELL CLUSTERS OR LINE SEGMENTS WHICH COULD PRODUCE SOME
SEVERE WEATHER IN THE FORM OF DAMAGING WINDS AND LARGE HAIL.

BY MONDAY EVENING...A STRONGER SHORTWAVE EMBEDDED WITHIN THE
LARGER SCALE UPPER TROUGH SHOULD EJECT TOWARDS THE MID SOUTH AND
PUSH A SECONDARY STRONGER COLD FRONT SOUTHWARD INTO THE REGION.
SHOWERS AND THUNDERSTORMS SHOULD ORGANIZE ALONG THE FRONT BY
MONDAY EVENING ACROSS NORTHERN PORTIONS OF THE MID SOUTH AND SURGE
SOUTHWARD OVERNIGHT. THE POTENTIAL FOR SEVERE WEATHER SHOULD
CONTINUE MONDAY NIGHT AS STRONGER FORCING ALOFT AND CONTINUED
MOIST UNSTABLE CONDITIONS...STRENGTHENING SHEAR...AND STRONG
SURFACE CONVERGENCE ALONG THE FRONT SUPPORTS A DEVELOPING SQUALL-
LINE. THE THREAT FOR DAMAGING WINDS AND LARGE HAIL SHOULD
CONTINUE ALONG WITH AREAS OF LOCALIZED HEAVY RAINFALL.

THE COLD FRONT AND ASSOCIATED NUMEROUS SHOWERS AND THUNDERSTORMS SHOULD
CONTINUE ADVANCING SOUTHWARD ACROSS THE REMAINDER OF THE FORECAST
AREA...SOUTH OF INTERSTATE 40...ON TUESDAY. A FEW STRONG TO SEVERE
STORMS CANNOT BE RULED OUT TUESDAY AFTERNOON IN THE SOUTH...BUT
UNCERTAINTY REGARDING OVERALL INSTABILITY REMAINS DUE TO EXPECTED
ONGOING STORMS FROM MONDAY NIGHT. COOL AND DRY HIGH PRESSURE WILL
BUILD INTO NORTHERN AREAS TUESDAY MORNING AND SPREAD SOUTH ACROSS
THE REMAINDER OF THE AREA BY TUESDAY NIGHT. HIGH PRESSURE SHOULD
KEEP CONDITIONS DRY AND COOL ON WEDNESDAY AREAWIDE WITH HIGH
TEMPERATURES RANGING FROM THE UPPER 70S TO LOWER 80S ALONG WITH
MUCH LOWER HUMIDITY LEVELS.

THE EARLY WEEK COLD FRONT SHOULD STALL OUT IN THE VICINITY OF THE
INTERSTATE 20 CORRIDOR IN SOUTH CENTRAL MISSISSIPPI THROUGH MID
WEEK. ANOTHER UPPER LEVEL SHORTWAVE SHOULD DIG ACROSS THE PLAINS
STATES WEDNESDAY NIGHT INTO THURSDAY. THIS SYSTEM SHOULD HELP TO
LIFT THE STALLED FRONT BACK TO THE NORTH AS A WARM FRONT.
ELEVATED SHOWERS AND THUNDERSTORMS SHOULD REFORM NORTH OF THE
FRONT LATE WEDNESDAY NIGHT AND CONTINUE INTO THURSDAY ACROSS
SOUTHERN PORTIONS OF THE MID SOUTH. THE SHORTWAVE SHOULD MOVE
SLOWLY ACROSS THE MID SOUTH FRIDAY THROUGH SATURDAY AS THE WARM
FRONT CONTINUES TO LIFT NORTH ACROSS THE AREA. IN ADDITION...LATEST
MODEL GUIDANCE SUGGESTS THAT A WEAK SURFACE WAVE OF LOW PRESSURE
SHOULD LIFT NORTHEAST ALONG THE FRONT ACROSS OUR AREA FRIDAY AND
FRIDAY NIGHT. THIS ALL POINTS TO INCREASING CHANCES FOR SHOWERS
AND THUNDERSTORMS ACROSS THE ENTIRE MID SOUTH FOR THE END OF THIS
WEEK INTO THE FIRST PART OF NEXT WEEKEND. THERE MAY EVEN BE SOME
POTENTIAL FOR HEAVY RAINFALL DURING THIS TIME PERIOD. HIGH
TEMPERATURES SHOULD BE HELD BELOW SEASONAL AVERAGES WITH ENHANCED
CLOUD COVER AND RAINFALL...WITH LOW TEMPERATURES NEAR NORMAL.

THE SHORTWAVE SHOULD MOVE EAST BY NEXT SUNDAY BUT WITH LINGERING
MOISTURE...ISOLATED SHOWERS AND THUNDERSTORMS SHOULD CONTINUE.
TEMPERATURES SHOULD WARM BACK TO NEAR NORMAL LEVELS BY THE END OF
NEXT WEEKEND.

JLH

&&

.AVIATION...

06Z TAFS

FEW CHANGES ANTICIPATED FOR THE 06Z TAFS. VFR WILL PREVAIL THROUGH
THE NEXT 24 HOURS...EXCEPT WHERE BRIEF MVFR VSBY FORMS AT MKL/TUP
EARLY THIS MORNING.

PWB

&&

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

$$






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