FXUS64 KSHV 141741
AFDSHV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
1141 AM CST MON DEC 14 2009
.DISCUSSION...
QUITE A FEW CHANGES NEEDED TO THE FORECAST THIS MORNING...AS CONVECTION
HAS BLOSSOMED AND BECOME WIDESPREAD ACROSS THE EXTREME SRN SECTIONS OF
THE FORECAST AREA...IN THE LFQ OF A WEAK SHORTWAVE/MID LEVEL SPEED MAX
TRAVERSING NE ACROSS THE EXTREME NW GULF THIS MORNING. RAINFALL RATES
HAVE BEEN FAIRLY IMPRESSIVE...AVERAGING 1-1.5"/HR...WHILE IT TRAINS
OVER THE SAME AREAS IN THE BROADLY UNIDIRECTIONAL FLOW JUST ABOVE THE
SFC. QUITE A FEW EMBEDDED ELEVATED STORMS HAVE ADDED TO THE RAIN
RATES AS WELL...ASSOCIATED WITH STEEP LAPSE RATES OBSERVED ABOVE 750MB
PER THE 12Z KSHV/KLCH RAOBS. LOW LEVEL MOISTURE IS ALSO QUITE A BIT
DEEPER AS WELL...WITH IT DEEPENING FURTHER AS THE WARM FRONT
ASSOCIATED WITH A SFC LOW JUST NE OF RKP...EXTENDS ALONG THE SE TX
COAST...INTO EXTREME SW LA TO JUST S OF I-10 ACROSS LAKE
PONTCHARTRAIN...CONTINUES TO SLOWLY LIFT NNW INTO CNTRL LA/MS THROUGH
THE AFTERNOON. HAVE ADDED HEAVY RAINFALL MENTION TO THE SRN SECTIONS
OF DEEP E TX/NCNTRL LA N OF THE FRONT...BUT WILL HOLD OFF FOR NOW ON A
FFA GIVEN VERY LIMITED AREAL COVERAGE. HOWEVER...ONE MAY BE NEEDED
OVERNIGHT AS ADDITIONAL REDEVELOPMENT OCCURS ALONG/AHEAD OF A SE
SURGING COLD FRONT THAT WILL MOVE THROUGH THE REGION.
THIS COLD FRONT HAS REACHED A FYV...TO MLC...TO GYI AND SWW LINE AS OF
17Z...WITH IT EXPECTED TO REACH MCCURTAIN COUNTY BETWEEN 18-19Z...AND
ALONG THE I-30 CORRIDOR BY 21Z. THE LOW CLOUDS ARE QUICKLY DIMINISHING
FROM W TO E ACROSS EXTREME NE TX...WITH THE WRLY WINDS ALLOW TEMPS TO
REACH THE FORECAST MAXES ALREADY. HAVE RAISED TEMPS SEVERAL
DEGREES...AS COMPRESSIONAL HEATING ALONG THE FRONTAL SFC WILL AID IN
ADDITIONAL WARMING. HOWEVER...NOT SURE IF LOW CLOUDS WILL COMPLETELY
CLEAR BEFORE THE FRONT ARRIVES...WHICH WILL HOLD TEMPS IN CHECK BEFORE
THE FROPA. GREATEST CONFIDENCE IS FOR AREAS OF NE TX N OF I-20...WITH
ADDITIONAL ISENTROPIC FORCING EXPECTED ALONG THE FRONT BY LATE
AFTERNOON. FOR THE TIME BEING...CONVECTION OVER TOLEDO BEND COUNTRY
AND CNTRL LA HAS CUT OFF THE SRLY INFLOW/ISENTROPIC FORCING
RESPONSIBLE FOR THE SHRA EARLIER THIS MORNING...AND THIS MAY BE THE
CASE THIS AFTERNOON UNTIL ADDITIONAL FORCING ARRIVES LATER TONIGHT AS
THE SHORTWAVE DIGGING SE THROUGH NRN BAJA MOVES INTO NRN MX...SETTING
UP A BROADLY DIFFLUENT UPPER FLOW REGIME IN VC OF THE WARM FRONT OVER
CNTRL LA/MS. THUS...GIVEN LOW CONFIDENCE...WILL LEAVE CURRENT SLIGHT
CHANCE/CHANCE POPS TAPERED FARTHER N TOWARDS THE I-20 CORRIDOR FOR THE
AFTERNOON.
ZONE UPDATE ALREADY OUT...GRIDS WILL BE AVAILABLE SHORTLY.
15
&&
.AVIATION...
MOST SITES THIS MORNING HAVE BEEN SEEING IFR TO MVFR CIGS. A FEW
LOCATIONS ARE SEEING BRIEF BREAKS TO GIVE PERIODS OF VFR. PATCHY
MVFR FOG IS STILL SEEN AT SOME SITES...BUT THESE SHOULD CONTINUE TO
IMPROVE THIS MORNING. SCATTERED SHOWERS WILL CONTINUE TO INCREASE IN
COVERAGE PRIMARILY FOR SOUTHERN AND EASTERN SITES. THIS COULD BRING
PERIODS OF LIGHT RAIN...WHICH MAY BRING REDUCTIONS TO FLIGHT
CATEGORIES AT TIMES. CIGS ARE EXPECTED TO LIFT TO MAINLY MVFR AND
VFR DURING THE AFTERNOON AND EARLY EVENING. THIS WILL ESPECIALLY BE
TRUE FOR SOME EAST TEXAS SITES AND TXK. CIGS FOR REMAINING SITES
MAY AGAIN FALL BELOW MVFR BY LATE EVENING AND INTO THE OVERNIGHT
HOURS. WINDS THIS MORNING ARE GENERALLY OUT OF THE SOUTH BELOW 10
KTS. A COLD FRONT IS EXPECTED TO PASS THROUGH THE REGION THIS
AFTERNOON INTO THIS EVENING. THIS WILL ALLOW WINDS TO SWITCH AROUND
TO THE NORTH TO NORTHWEST FOR TONIGHT AND INTO TUESDAY...WITH WIND
SPEEDS INCREASING TO 5-10 KTS WITH POSSIBLE HIGHER GUSTS. /22/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 66 46 51 32 55 / 20 30 20 0 0
MLU 65 49 50 32 55 / 40 40 20 0 0
DEQ 58 38 49 24 56 / 10 10 10 0 0
TXK 63 41 50 28 55 / 10 10 10 0 0
ELD 64 44 50 30 55 / 20 30 10 0 0
TYR 66 42 50 32 57 / 20 30 10 0 0
GGG 66 44 51 32 56 / 20 30 20 0 0
LFK 62 49 53 35 58 / 50 50 40 0 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
15/22
