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000
FXUS64 KOHX 140517
AFDOHX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
1217 AM CDT FRI MAR 14 2014

.UPDATE...FOR 06Z AVIATION FORECASTS.

&&

.AVIATION...
VFR CONDITIONS EXPECTED DURING THIS 24 HOUR PERIOD. LIGHT SOUTH
BREEZES DEVELOPED THIS EVENING AFTER SFC RIDGE MOVED EAST OF THE
REGION. THESE WINDS WILL CONTINUE THE REST OF THE NIGHT...THEN
BECOME SW AND INCREASE TO 15 TO 25 KTS BY MID MORNING FRIDAY AS
GRADIENTS TIGHTEN DUE TO TROUGH MOVING THOUGH THE OH VALLEY. AREA
OF HIGH CLOUDS OVER SWRN U.S. PROGGED TO SWEEP INTO MIDDLE TN
DURING THE DAY ON FRIDAY.

&&

.PREV DISCUSSION... /ISSUED 915 PM CDT THU MAR 13 2014/

UPDATE...

QUITE A TEMPERATURE RANGE ACROSS THE FORECAST AREA THIS EVENING
FROM MID 40S ALONG THE TENNESSEE RIVER TO UPPER 20S JUST WEST OF
THE PLATEAU. TEMPS EXPECTED TO BOTTOM OUT THIS EVENING BEFORE
REMAINING STEADY OR SLOWLY RISING OVERNIGHT AS SOUTHERLY WINDS
INCREASE AT THE SURFACE AND ALOFT. HAVE LOWERED MIN TEMPS AND
ADJUSTED HOURLY TEMPS TO REFLECT THIS REASONING. OTHERWISE...MINOR
CHANGES MADE TO SKY COVER AND OTHER GRIDS BASED ON LATEST OBS.
UPDATED PRODUCTS OUT SHORTLY.

SHAMBURGER

PREV DISCUSSION... /ISSUED 817 PM CDT THU MAR 13 2014/

UPDATE...FOR 00Z AVIATION FORECAST.

AVIATION...
VFR CONDITIONS EXPECTED ACROSS THE REGION FOR THIS 24 HOUR PERIOD.
SFC RIDGE HAS MOVED EAST AND ALLOWED SOUTHERLY WINDS TO BEGIN.
SPEEDS WILL STAY LOW OVERNIGHT BUT INCREASE TO 15 TO 25 KNOTS BY
MIDMORNING FRIDAY IN RESPONSE TO TROF THAT WILL BE MOVING INTO THE
OH VALLEY.

PREV DISCUSSION... /ISSUED 315 PM CDT THU MAR 13 2014/

DISCUSSION...
FOR TONIGHT...CLEAR SKIES SHOULD PREVAIL. AIRMASS IS QUITE DRY SO
ONE WOULD EXPECT GOOD RADIATIONAL COOLING. BUT...LOW LEVEL WIND
FLOW TO INCREASE OVERNIGHT AND WILL ACT TO KEEP CONDITIONS STIRRED
UP. THUS...WILL ONLY UNDERCUT THE MAV 38F FOR BNA BY 1 DEGREE.

OTW...SFC LOW CURRENTLY LOCATED OVER SOUTHERN CANADA WITH A TRAILING
COLD FRONT SOUTHWARD THROUGH THE PLAINS. MEANWHILE...A SFC HIGH
RESIDES OVER THE TX COAST. BOTH OF THESE FEATURES WILL MOVE EASTWARD
AND STRENGTHEN BY FRIDAY. THOUGH THE SOUTHERN END OF THE COLD FRONT
WILL WEAKEN...THE PRESSURE GRADIENT BETWEEN BOTH FEATURES WILL
TIGHTEN DURING THE DAY. RIGHT NOW...EXPECTED WIND SPEEDS LOOK TO BE
A LITTLE BELOW ADVISORY LEVELS. DEGREE OF SUBSIDENCE...COMBINED WITH
RELATIVELY UNIMPRESSIVE LOWER LEVEL SPEEDS...DOES NOT LOOK TO
SUPPORT ADVISORY CONDITIONS AT THIS POINT IN TIME.

FRIDAY NIGHT INTO SATURDAY...CLOUDS WILL BE ON THE INCREASE AS A
STORM SYSTEM BEGINS TO DEVELOP OVER TX. THIS TX STORM WILL BE AIDED
IN DEVELOPMENT BY A STRONG SHORTWAVE WHICH WILL DROP QUICKLY TO THE
SOUTHEAST ALONG THE LEE OF THE ROCKIES. AS THE INGREDIENTS COME
TOGETHER...CYCLOGENESIS IS EXPECTED AS THE SFC LOW MOVES EASTWARD
ACROSS THE DEEP SOUTH. AIRMASS TO THE NORTH FEEDING INTO THE SYSTEM
IS NOT THAT COLD AND THUS...ALL RAIN IS EXPECTED. RAINFALL AMOUNTS
OF A GOOD HALF TO THREE QUARTERS OF AN INCH WILL BE POSSIBLE SAT NT
INTO SUNDAY AS THE LOWER LEVEL OVERRUNNING AND FORCING DYNAMICS
PREVAIL. IN FACT...MOISTURE OVERRIDE PARAMETERS ARE IN PLACE ACROSS
SOUTHWESTERN ZONES FOR SATURDAY NIGHT AND THUS...CATEGORICAL POPS
WILL BE NEEDED.

ON SUNDAY NIGHT...THE UPPER LEVEL ENERGY MIGHT BECOME MORE OF A
DIRECT PLAYER. BUT...THOUGH THE GFS CLOSES THE LOW OFF...IT TAKES A
TRACK WELL TO THE SOUTH OF TN. THUS...RAINFALL CHANCES WILL BE ON
THE LOW SIDE. UPON LOOKING AT THE CLOSED LOW...IT LOOKS POTENTIALLY
WINTRY AT FIRST GLANCE. HOWEVER...THE POSITIONING OF THE SFC LOW
RELATIVE TO THE UPPER LOW IS NOT SUITABLE FOR SUPER COLD CORE
DEVELOPMENT. AND THUS...THIS LOOKS TO BE MOSTLY A COLD RAIN
EVENT...EVEN IN THE DEFORMATION ZONE TO THE NORTH OF THE CLOSE
LOW. STILL THOUGH...WILL UNDERCUT TEMPS AND FUTURE RUNS WILL NEED TO
BE MONITORED IN THE EVENT THAT MORE IN THE WAY OF SUB FREEZING 850
MB TEMPS WERE TO EMERGE IN CONJUNCTION WITH THE UPPER LOW ITSELF.
I WILL INCLUDE A CHANCE OF RAIN AND SNOW FOR NORTHERN AREAS ON THE
BACK EDGE OF THE SYSTEM ON SUNDAY NIGHT.

FOR THE REMAINDER OF THE EXTENDED...GFS AND EURO SOLUTIONS FAIL TO
MATCH UP BUT BOTH LEAN TOWARD A FEW QUICK MOVING SHOWER PRODUCING
SYSTEMS. THUS...WILL INCLUDE LOWER RAIN CHANCES TUES NT THROUGH
THURSDAY. TEMPS WILL BE CLOSE TO SEASONAL.

&&

.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$
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