FXUS64 KMEG 151151
AFDMEG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEMPHIS TN
551 AM CST TUE DEC 15 2009

.UPDATE...

UPDATED FOR 12Z TAF DISCUSSION.

&&

.PREV DISCUSSION... /ISSUED 521 AM CST TUE DEC 15 2009/ 

DISCUSSION...10Z SURFACE ANALYSIS PLACES AN ARCTIC COLD FRONT
STRETCHING FROM NEW ENGLAND BACK THROUGH EASTERN TENNESSEE AND
NORTHERN ALABAMA/CENTRAL MISSISSIPPI. MEANWHILE...A 1037 MB RIDGE
OF HIGH PRESSURE WAS CENTERED ACROSS THE NORTHERN AND CENTRAL
PLAINS THIS MORNING. TEMPERATURES AS OF 4 AM CST RANGE FROM THE
UPPER 30S ACROSS EAST ARKANSAS AND NORTHWEST TENNESSEE TO THE
MIDDLE 40S TO AROUND 50 ACROSS NORTH MISSISSIPPI. TEMPERATURES AND
PRECIPITATION CHANCES THIS WEEKEND ARE THE MAIN CONCERNS IN THIS
MORNING/S FORECAST PACKAGE.

SHORT TERM...(TODAY THROUGH THURSDAY NIGHT)...AN ARCTIC COLD
FRONT STRETCHING FROM EAST TENNESSEE THROUGH CENTRAL/SOUTHERN
MISSISSIPPI WILL CONTINUE TO PUSH SOUTHEAST THROUGHOUT THE DAY.
310K SURFACE SHOWS SATURATION ALONG WITH WEAK ISENTROPIC ASCENT
ACROSS SOUTHERN/CENTRAL MISSISSIPPI INTO PORTIONS OF NORTH
MISSISSIPPI THIS MORNING. BASED ON REGIONAL WSR-88D RADAR TRENDS
OVER MISSISSIPPI/LOUISIANA OVER THE PAST FEW HOURS THINK ISOLATED
RAIN SHOWER ACTIVITY WILL ONLY REACH AS FAR NORTH AS THE SOUTHERN
TIER OF COUNTIES IN NORTH MISSISSIPPI THROUGH MID-MORNING BEFORE
DEPARTING THE AREA. POPS FROM PREVIOUS FORECAST PACKAGE WERE
REASONABLE AND ONLY MADE MINOR ADJUSTMENTS FOR CURRENT TRENDS.

TEMPERATURES TODAY WILL CONTINUE TO DROP BEHIND THE ARCTIC COLD
FRONT WITH HIGHS OCCURRING THIS MORNING. WRF/GFS SHORT TERM MODELS
AND SOUNDINGS INDICATE POST-FRONTAL LOW CLOUDS TRAPPED UNDER A
STRONG SUBSIDENCE INVERSION WILL BEGIN TO DISSIPATE BY THIS
AFTERNOON...LEADING TO MOSTLY SUNNY SKIES BY LATE THIS AFTERNOON. 
HIGH PRESSURE WILL MOVE TONIGHT INTO THE MISSISSIPPI VALLEY
BRINGING VERY COLD TEMPERATURES TONIGHT IN THE 20S TO THE FORECAST
AREA. PRECIPITATION FREE WEATHER WILL CONTINUE FOR THE MID SOUTH
THROUGH THE REMAINDER OF THE SHORT TERM FORECAST.

LONG TERM...(FRIDAY THROUGH MONDAY)...LONG RANGE MODEL RUN TO RUN
CONTINUITY CONTINUES TO PLAGUE THE LONG TERM FORECAST PRODUCING
LOW CONFIDENCE IN POPS FOR THE PERIOD. PREFERRED 00Z GFS/GFS
ENSEMBLE RUNS OVER THE ECMWF SOLUTION FOR THE LONG RANGE FORECAST
THIS MORNING AND KEPT REASONABLE CONTINUITY FROM YESTERDAY/S
AFTERNOON FORECAST PACKAGE. 00Z GFS INDICATES A COLD FRONT COMING
THROUGH THE MID SOUTH FRIDAY INTO SATURDAY AND KEPT 20 POPS GOING
FOR FRIDAY NIGHT THROUGH SATURDAY NIGHT. 00Z GFS MODEL SOUNDINGS
SUGGEST PRECIPITATION FRIDAY NIGHT AND SATURDAY NIGHT WOULD BE IN
THE FORM OF PERHAPS LIGHT SNOW OR FLURRIES AND LIGHT RAIN DURING
THE DAY SATURDAY GIVEN LOW PRECIPITABLE WATER VALUES. OTHERWISE...THE
REMAINDER OF THE LONG TERM FORECAST IS EXPECTED TO BE
PRECIPITATION FREE.

CJC

&&

.AVIATION...

12Z TAF CYCLE

MODEL SOUNDINGS CONTINUE TO DEPICT AMPLE LOW LEVEL MOISTURE
TRAPPED UNDER A 925 MB INVERSION. KEPT MVFR CIGS THROUGH 15Z AT
ALL SITES WITH THE EXCEPTION OF KTUP WHICH SHOULD STAY AT MVFR
THROUGH THE EARLY AFTERNOON HOURS. SKIES SHOULD SCATTER OUT AT ALL
SITES THROUGH THE LATTER HALF OF THE PERIOD. NORTHERLY WINDS WILL
ALSO INCREASE AND BECOME GUSTY THROUGH THE DAY BEFORE SLOWLY
TAPERING OFF TO A 6-10KT RANGE MAINLY AFTER 00Z.

CCD

&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  41  26  46  26 /  10   0   0   0 
MKL  42  22  43  22 /  10   0   0   0 
JBR  39  22  42  25 /   0   0   0   0 
TUP  48  29  48  27 /  10   0   0   0 

&&

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

$$