FXUS64 KSHV 080254 AAA
AFDSHV
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SHREVEPORT LA
855 PM CST MON DEC 7 2009
UPDATED FOR AVIATION DISCUSSION.
.DISCUSSION...
01Z SFC ANALYSIS SHOWING A STATIONARY BOUNDARY ACROSS SE LA INTO
THE NORTHERN GULF AND INTO SOUTHERN TEXAS. IN THE WAKE OF THIS
BOUNDARY...A WEAK SFC TROUGH WAS OBSERVED FROM NW AR INTO SE OK AND
CENTRAL TX. DESPITE THE COOL AIR MASS IN PLACE...ISENTROPIC LIFT
WAS BEGINNING TO GENERATE SCATTERED TO NUMEROUS SHOWERS ACROSS THE
REGION AND EVEN HAD A LIGHTNING STRIKE DURING THE PAST HOUR SW OF
LUFKIN TEXAS.
NAM THETA SFCS SUPPORT THIS LIFT CONTINUING THROUGH THE NIGHT IN
ADVANCE OF 40KT LOW LEVEL JET DEVELOPING ACROSS CENTRAL AND
NORTHEAST TEXAS OVERNIGHT. LAPSE RATES ARE KIND OF MARGINAL BUT
CANNOT RULE OUT AN ISOLATED THUNDERSTORM DURING THE NIGHT AS WELL.
IN ADDITION TO THE RAIN...ADDED MENTION OF PATCHY FOG ACROSS THE
REGION TONIGHT IN AND AWAY FROM PRECIPITATION.
MADE SOME SIGNIFICANT CHANGES TONIGHT CONCERNING OVERNIGHT MIN
TEMPERATURES. OBSERVED MINS WERE ALREADY BELOW OVERNIGHT FCST MIN
TEMPS AND THUS HAD TO ACCOUNT FOR THIS. THERE IS QUITE A BIT OF
DISCREPANCY CONCERNING THE BOUNDARY TO OUR SOUTH AND JUST HOW FAR
NORTH IT WILL RETURN NORTHWARD DURING THE DAY TUESDAY. GFS IS MUCH
FURTHER NORTH AND THUS MUCH WARMER THAN 18Z NAM GUIDANCE. TRIED TO
SHOW BLEND THE TWO PROGS WHICH WILL ACCOUNT FOR THE BOUNDARY
PULLING UP STATIONARY JUST SOUTH OF THE I-20 CORRIDOR BUT WOULD
NOT BE SURPRISED TO SEE IT COME NORTH OF MLU.
COMPLETE UPDATED FCST PACKAGE HAS ALREADY BEEN SENT.
13
&&
.AVIATION...
POOR FLIGHT CONDITIONS WILL PERSIST THROUGHOUT MUCH OF THE TAF
PERIOD...AS CURRENT LIFR CIGS/REDUCED VSBYS ALONG AND S OF THE I-20
CORRIDOR OF E TX/N LA...GRADUALLY SPREADS NNW AFFECTING THE SW
AR/EXTREME NE TX TERMINALS. MEANWHILE...STRONG OVERRUNNING WILL
CONTINUE ATOP A STATIONARY FRONTAL BNDRY EXTENDING FROM JUST
OFFSHORE THE TX COASTAL BEND...NE ACROSS THE EXTREME NW GULF ALONG
THE SCNTRL LA COAST INTO EXTREME SE LA. THIS HAS RESULTED IN LARGE
AREAS OF SHRA DEVELOPING FROM SE TX INTO SRN/CNTRL LA...AND SURGING
N INTO NE TX AND THE SRN SECTIONS OF NCNTRL LA ATTM. THUS...BELIEVE
THAT THE SHRA WILL BECOME MORE WIDESPREAD ACROSS OUR REGION BETWEEN
03-06Z...ESPECIALLY AS THE STATIONARY FRONT TO THE S BEGINS TO BACK
N AS A WARM FRONT AFTER 06Z...EXTENDING FROM EXTREME SE TX INTO
NCNTRL/NE LA BY TUESDAY AFTERNOON. WE MAY ACTUALLY SEE 2 ROUNDS OF
SIGNIFICANT RAINFALL...THE FIRST THIS EVENING POSSIBLY DIMINISHING
SOME AROUND 12Z...WITH A SECOND ROUND DEVELOPING IN VC OF THE WARM
FRONT BY MIDMORNING...BECOMING WIDESPREAD AROUND MIDDAY. BEST
CHANCES OF EMBEDDED THUNDER WILL RESIDE CLOSEST TO THE WARM
FRONT...NAMELY AFFECTING THE LFK/MLU TERMINALS. WILL MAINTAIN
THUNDER IN THE MLU TAF WITH THE 06Z ISSUANCE...BUT WILL FOREGO
MENTION ELSEWHERE AND ALLOW LATER SHIFTS TO MONITOR. SHOULD THE
FIRST ROUND OF RAIN DIMINISH SIGNIFICANTLY BEFORE ROUND TWO ARRIVE
TUESDAY MORNING...WILL LIKELY SEE A PERIOD OF VLIFR CIGS AND DENSE
FG DEVELOP ACROSS E TX/N LA...WITH CONDITIONS IMPROVING SLIGHTLY
ONCE THE SHRA AND EMBEDDED THUNDER ARRIVES AGAIN. WHILE ROUND TWO IS
EXPECTED TO DIMINISH FROM W TO E TUESDAY AFTERNOON...IFR CIGS AND
POSSIBLY SOME -DZ MAY PERSIST THROUGH THE EVENING...BEFORE A COLD
FRONT SWEEPS THROUGH THE REGION TUESDAY NIGHT...WITH CIGS/VSBYS
IMPROVING MARKEDLY BY 12Z WEDNESDAY. WINDS WILL REMAIN ENE 5-10KTS N
OF THE WARM FRONT TONIGHT...BEFORE BECOMING SSW 5-10KTS AREAWIDE
TUESDAY. /15/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 43 62 41 51 28 / 90 70 50 0 0
MLU 44 66 46 56 29 / 90 70 70 0 0
DEQ 41 52 33 42 22 / 70 50 30 0 0
TXK 42 53 38 47 25 / 80 60 40 0 0
ELD 41 57 40 52 26 / 90 70 60 0 0
TYR 43 55 38 49 26 / 80 70 30 0 0
GGG 43 58 39 50 25 / 80 60 40 0 0
LFK 49 66 47 56 31 / 90 70 30 0 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
13/15
