FXUS64 KSHV 292117
AFDSHV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
317 PM CST SUN NOV 29 2009
.DISCUSSION...
BKN LINE OF CONVECTION GRADUALLY BECMG BETTER ORGANISED...OUT
AHEAD OF COLD FRONT STILL JUST OUTSIDE CWA. CONVECTION BECOMING
MORE WIDESPREAD THIS EVENING...AND INCREASE ACROSS LA PORTIONS OF
AREA BY OR AFTER MIDNIGHT. UNDEASONALLY BALMY DEWPOINTS IN LOWER
TO MID 60S...SPREADING INTO AREA AND MAY SEE INCREASE IN
CONVECTIVE RAINFALL RATES. COLD FRONT TO PUSH THRU CWA BY LATE SUNDAY
NIGHT...WITH SOME POSTFRONTAL RAIN EXPECTED...AS IS SEEN CURRENTLY
ACROSS MUCH OF EASTERN OK. UPER LVL TROF...SEEN ON SATELLITE
MOVING INTO NORTHERN KS...WILL BRING AN END TO PCPN FROM THE NORTH
AND MOSTLY CLEAR SKIES. HOWEVER...CLOSED UPPER LOW SLIDING INTO NW
MEXICO...WILL MOVE INTO THE BIG BEND TX AREA TUE AFTN. BASING
TRACK OF LOW WITH ECMWF...WHICH IS MORE CONSISTENT WITH SLOWER NAM
GUIDANCE...WHICH IS MORE REASONABLE CONSIDERING HOW CLOSED THIS
LOW PRESSURE IS...WELL SEPARATED FROM MAIN UPPER JET...MOVING INTO
GREAT LAKES REGION. A HEAVY CIRRUS CANOPY WILL SPREAD ACROSS AREA
LATE MONDAY...THUS ANY CLEARING SKIES...MAINLY NORTHERN CWA...WILL
BE BRIEF. ALTHOUGH MODEL UNCERTAINTLY DICTATE WHETHER OVERRUNNING
RAIN FIELDS ADVANCE FROM THE WEST...OR BUILD NORTHWARD FROM THE COAST...
LEANING ON A MORE NORTHWARD MOVEMENT...WITH AREAS NEAR LA/TX
COASTS RECEIEVING GREATEST AMOUNT OF RAINFALL. SOME INITIAL
CONCERNS FOR LIGHT SNOW...OR RAIN SNOW MIX...PUT ON HOLD WITH
LATEST MODEL GUIDANCE...WHILE KEEPING HEAVY SNOWFALL OVER SOUTHERN
HIGH PLAINS...NOT IN GOOD ENOUGH MODEL AGREEMENT OVER RED RIVER
VALLEY REGION TO INCLUDE IN FCST YET.
AS THIS UPPER LOW MOVES NEARLY OVERHEAD ACROSS AREA...TAPER OFF
POPS WED NIGHT...AND PLACE NEAR FREEZING TEMPS ACROSS CWA THU
NIGHT AS A 1030 MB HIGH SHIFTS INTO AREA...WITH DECENT RADIATION
COOLING EXPECTED. SFC LOW MAY DEVELOP OVER PANHANDLE REGION OVER
THE WEEKEND...MODERATING TEMPS AND PROVIDING AT LEAST A LOW CHANCE
OF RAIN. HINTS OF POLAR COLD AIRMASS...IN FORM OF 1050 MB
HIGH...FILTERING SOUTH OF EXTREME WESTERN CANADA...WHICH MAY
PROVIDE EVEN COLDER TEMPS TO THE AREA...AFTER END OF EXTENDED FCST PERIOD./VII/
&&
.AVIATION...
SHOWERS AND THUNDERSTORMS BREAKING OUT ACROSS THE WESTERN AND
NORTHWEST PORTIONS OF THE AREA ATTM JUST AHEAD OF THE FRONT LOCATED
FROM CENTRAL ARKANSAS TO THE DFW METRO AREA. EXPECT VSBYS TO DROP
IN THE HEAVIER SHOWERS AND CIGS TO FALL TO IFR NEAR THE FRONT.
WINDS WILL SHIFT TO THE NORTHWEST BEHIND THE FRONT AND GUST TO NEAR
20 IN SOME LOCATIONS. FRONT SHOULD PASS THROUGH TYR AND TXK AROUND
03Z...SHV AROUND 06Z...MLU AND LFK AROUND 10Z. IFR CIGS AND SHRA
ACTIVITY WILL LAG BEHIND THE FRONT THROUGH MOST OF THE TAF PERIOD
WITH A CHANCE TO BREAK OUT AT THE END OF THIS CYCLE. /04/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 53 60 42 56 47 / 90 20 10 50 70
MLU 53 60 42 56 49 / 90 30 10 50 70
DEQ 44 54 37 57 44 / 80 10 0 30 60
TXK 46 56 39 57 45 / 80 10 0 30 60
ELD 50 58 38 57 46 / 90 20 0 30 60
TYR 47 55 42 55 46 / 70 10 10 60 70
GGG 49 58 42 55 46 / 70 10 10 60 70
LFK 57 61 44 52 48 / 80 40 30 60 70
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
