National Weather Service Raw Text Product

737 
FXUS63 KLSX 032154
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
353 PM CST SUN FEB 3 2013

.SHORT TERM...
ISSUED AT 352 PM CST SUN FEB 3 2013
(TONIGHT)

SURFACE RIDGE MOVING INTO REGION LATE THIS AFTERNOON WITH WINDS 
DIMINISHING. HOWEVER...RIDGE WILL NOT REMAIN OVER AREA FOR VERY LONG 
AND SHOULD SLIDE OFF TO OUR EAST THIS EVENING ALLOWING SOUTHERLY 
WINDS TO RETURN TO THE REGION. ALL OF THIS IS AHEAD OF NEXT WEATHER 
SYSTEM. TEMPERATURES TO DROP OFF  INTO THE LOW 20S TO LOW 30S FAIRLY 
QUICKLY AFTER SUNSET DUE TO LIGHT WINDS...CLEAR SKIES AND SNOW COVER 
OVER PORTIONS OF THE AREA. THEN AS RIDGE MOVES OFF AND SOUTHERLY 
WINDS PICKUP ALONG WITH INCREASING MID AND HIGH CLOUDS... 
TEMPERATURES TO REMAIN STEADY OR SLOWLY RISE TOWARDS DAYBREAK. 

BYRD

&&

.LONG TERM...
ISSUED AT 352 PM CST SUN FEB 3 2013
(MONDAY-THURSDAY)

THE NEXT IN A SERIES OF FAST MOVING SHORTWAVES WILL BE PRESSING INTO 
THE AREA TOMORROW.  ALL OF THE 12Z RUNS ARE NOW DEPICTING THE 
DEEPEST MOISTURE RETURN TO BE A BIT SLOWER AND BE SHUNTED MORE E 
THAN N...ESSENTIALL CONFINING PRECIP TO S MO AND JUST CLIPPING FAR S 
SECTIONS OF THE CWA.  SINCE THIS IS THE FIRST MODEL SUITE TO DEPICT 
THIS TREND WILL BE HOLDING ONTO CHANCE POPS AS FAR N AS THE 
I-44/I-70 CORRIDOR FOR NOW.   

THERE WILL LIKELY BE A HUGE TEMPERATURE GRADIENT ACROSS THE AREA ON 
MONDAY...AS SURFACE LOW TRACKS FROM NE MO INTO SE IN BY LATE IN THE 
DAY.  EARLY ARRIVAL OF THE COLD AIR OVER N COUNTIES WILL MEAN AN 
MORNING HIGH IN THE 30S WITH TEMPS SLOWLY FALLING DURING THE DAY.  
MEANWHILE...BRIEF BUT FAIRLY STOUT SURGE OF WARM AIR IN ADVANCE OF 
THE LOW SHOULD MEAN A NICE WARMUP FOR S SECTIONS OF THE CWA.   
EXTENT OF THE WARMUP WILL BE GREATLY IMPACTED BY CLOUD COVER...BUT 
FOR NOW LOOKS LIKE LOWER 50S WILL BE ATTAINED BEFORE THE ARRIVAL OF 
THE COLD FRONT...AND COLD AIR...IN THE AFTERNOON.

12Z RUNS ARE NOT BACKING AWAY FROM THE TRANSITION TO A ZONAL FLOW 
PATTERN OVER THE MID MISSISSIPPI VALLEY BY MIDWEEK.  THIS WILL ALLOW 
RIDGE IN THE WAKE OF MONDAY'S SYSTEM TO WORK ACROSS THE AREA MONDAY 
NIGHT...WITH RETURN FLOW QUICKLY DEVELOPING BY TUESDAY.  THE GRADUAL 
N SHIFT OF THE WESTERLIES WILL MEAN THE NEXT DISTURBANCE IN THE 
SHORTWAVE PARADE WILL IMPACT UPPER MISSISSIPPI VALLEY AND UPPER 
LAKES REGION...WITH LITTLE IF ANY PRECIP THREAT IN OUR AREA.  
TEMPERATURES SHOULD BE FAIRLY MILD ON TUESDAY AS THE AMS MODERATES 
ACROSS AREA...AND NWD SHIFT IN THE TRACK OF THE SHORTWAVES WILL ALSO 
MEAN COOL AIR IN THE WAKE OF THE SYSTEM WILL ONLY MAKE A GLANCING 
BLOW IN OUR CWA ON TUESDAY NIGHT.  

LOW LEVEL RETURN FLOW FORECAST TO DEVELOP ON WEDNESDAY AS BROAD 
SHORTWAVE PUSHES INTO THE PLAINS.  MEDIUM RANGE SOLUTIONS ARE 
MAINTAINING FAIRLY GOOD CONTINUITY ON MOVEMENT OF THIS SYSTEM INTO 
OUR AREA...AND WILL MAINTAIN CHANCE POPS OVER THE NW PART OF OUR CWA 
ON WEDNESDAY NIGHT...WITH THE RAIN THREAT EXPANDING OVER THE 
REMAINDER OF THE AREA ON THURSDAY.  POPS SHOULD BE RAMPING UP TO 
HIGH CHANCE AND LOW LIKELY CATEGORIES OVER THE SOUTHEAST HALF OF THE 
CWA ON THURSDAY AS THERE SHOULD BE A FAIRLY SUBSTANTIAL MOISTURE 
INCREASE INTO THIS PART OF THE CWA BY THIS TIME.

WED-THU TEMPS SHOULD REMAIN ABOVE AVERAGE...WITH HIGHS IN THE MID 
40S TO MID 50S.   

(FRIDAY-SUNDAY)
MODELS HAVE SLOWED E PROGRESSION OF STRONG UPPER SYSTEM THAT IS 
PROGGED TO PUSH FROM THE WEST COAST INTO THE PLAINS DURING THIS 
TIME.   DUE TO THIS HAVE SLOWED THE ONSET OF PRECIP INTO OUR AREA ON 
SATURDAY...HOWEVER ONCE SYSTEM DOES MAKE IT INTO THE CENTRAL U.S. 
PRECIP THREAT SHOULD BE FAIRLY HIGH.  FOR NOW HAVE HIGH CHANCE POPS 
FOR THE ENTIRE AREA SATURDAY NIGHT AND SUNDAY.

TEMPS WILL DIP JUST A BIT FRIDAY DUE TO THE COOL ADVECTION IN THE 
WAKE OF THURSDAY'S SHORTWAVE...BUT SHOULD JUMP BACK INTO THE UPPER 
40S AND 50S DURING THE WEEKEND.  THIS MAY NOT BE WARM ENOUGH...BUT 
DIDN'T WANT TO GO TOO WARM AT THIS POINT DUE TO EXPECTED CLOUD COVER 
AND WHAT SHOULD BE FAIRLY WIDESPREAD PRECIP.

TRUETT

&&

.AVIATION...
ISSUED AT 1210 PM CST SUN FEB 3 2013

CLOUDS HAVE MOVED OUT OF TAF SITES...SO MAIN ISSUE IN THE SHORT
TERM IS THE GUSTY NORTHWEST WINDS. SURFACE RIDGE IS QUICKLY
BUILDING IN...SO WINDS TO DIMINISH...BECOMING LIGHT AND VARIABLE
BY LATE THIS AFTERNOON...THEN VEER TO THE SOUTH AND PICKUP A BIT AS
RIDGE MOVES OFF TO OUR EAST BY MID EVENING. ALL OF THIS IS AHEAD
OF NEXT WEATHER SYSTEM THAT WILL SLIDE THROUGH AFTER 12Z
MONDAY...EXITING TAF SITES BY 18Z MONDAY. WINDS TO VEER TO THE
SOUTHWEST THEN WEST TO NORTHWEST BEHIND THE COLD FRONT AND PICKUP
TO AROUND 15KTS. AS FOR CLOUDS...JUST EXPECT MID AND HIGH
CLOUDS...THOUGH SOME MVFR SC POSSIBLE...ESPECIALLY OVER KUIN...AS
IT WILL BE CLOSER TO SURFACE LOW.

SPECIFICS FOR KSTL...CLOUDS HAVE MOVED OUT OF METRO AREA...SO MAIN
ISSUE IN THE SHORT TERM IS THE GUSTY NORTHWEST WINDS. SURFACE
RIDGE IS QUICKLY BUILDING IN...SO WINDS TO DIMINISH...BECOMING
LIGHT AND VARIABLE BY 23Z...THEN VEER TO THE SOUTH AND PICKUP A BIT
AS RIDGE MOVES OFF TO OUR EAST BY 03Z MONDAY. ALL OF THIS IS
AHEAD OF NEXT WEATHER SYSTEM THAT WILL SLIDE THROUGH KSTL BY 17Z 
MONDAY. WINDS TO VEER TO THE SOUTHWEST THEN WEST TO NORTHWEST
BEHIND THE COLD FRONT AND PICKUP TO AROUND 15KTS. AS FOR
CLOUDS...JUST EXPECT MID AND HIGH CLOUDS.

BYRD

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX