072
FXUS63 KLSX 170940
AFDLSX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAINT LOUIS MO
340 AM CST FRI JAN 17 2025
KEY MESSAGES
- TODAY WILL BE THE WARMEST SO FAR THIS MONTH WITH HIGHS IN THE 40S
AND 50S. TEMPERATURES WILL QUICKLY DROP ON SATURDAY WITH MUCH
COLDER WEATHER EXPECTED FOR THE FIRST HALF OF NEXT WEEK.
- WIDESPREAD LIGHT RAIN IS EXPECTED TONIGHT WITH THE HIGHEST
CHANCE (70-100%) IN SOUTHWEST ILLINOIS AND SOUTHEAST MISSOURI.
DRY WEATHER IS THEN EXPECTED THROUGH NEXT WEEK.
SHORT TERM
(THROUGH LATE SATURDAY AFTERNOON)
ISSUED AT 339 AM CST FRI JAN 17 2025
WE ARE STILL ON TRACK TO WARM BACK UP AGAIN TODAY WITH HIGH
TEMPERATURES THIS AFTERNOON EXPECTED TO BE 10 TO 20 DEGREE ABOVE
NORMAL. A SURFACE HIGH HAS ALREADY MOVED OFF TO THE EAST EARLY THIS
MORNING ALLOWING WINDS TO BEGIN TO PICK UP OUT OF THE SOUTH ACROSS
MISSOURI. THIS TREND WILL CONTINUE THROUGH THE DAY BRINGING WARMER
AIR INTO THE CWA. THERE WILL BE A DECENT AMOUNT OF SUNSHINE TO HELP
WITH THE WARM-UP BEFORE CLOUDS MOVE INTO THE AREA LATER TODAY. WENT
CLOSE TO CAM GUIDANCE INCLUDING THE HRRR WHICH HAS LOW TO MID 50S
ALONG AND WEST OF THE MS RIVER WITH 40S OVER SOUTH CENTRAL IL.
THE ROUND OF LIGHT RAIN IS STILL EXPECTED TO MOVE INTO THE CWA BY
LATE THIS AFTERNOON AND THIS EVENING AS THE NAM/GFS ARE SHOWING A
SHORTWAVE TROUGH SHEARING OUT ON THE FRONT SIDE OF A LONGWAVE TROUGH
THAT WILL BE DROPPING OUT OF CANADA. THERE WILL BE MODEST 850-700MB
FRONTOGENESIS WITH THIS TROUGH THAT WILL BE CONCENTRATED ACROSS THE
SOUTHEAST HALF OF THE CWA FROM LATE THIS AFTERNOON THROUGH TONIGHT.
HREF PROBABILITIES SUPPORT 70-100% POPS TONIGHT OVER THIS SAME AREA
WITH LPMM SHOWING 1/4-3/4" OF RAINFALL SOUTH OF I-44 IN MO AND I-70
IN IL. WHILE THERE COULD BE SOME SNOWFLAKES MIXED IN AS THE RAIN
ENDS, RAP/NAM FORECAST SOUNDINGS AND HREF PROBABILITIES STILL
INDICATE THAT THIS WILL BE A SHORT WINDOW AND ACCUMULATING SNOW IS
NOT EXPECTED.
THE COLD FRONT THAT IS CURRENTLY OVER THE NORTHERN PLAINS IS STILL
EXPECTED TO MOVE SOUTHEAST ACROSS THE CWA TONIGHT. STRONG CAA
BEHIND IT ON SATURDAY WILL CAUSE HIGH TEMPERATURES TO BE 20 TO 25
DEGREES COLDER THAN TODAY.
BRITT
LONG TERM
(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 339 AM CST FRI JAN 17 2025
THE COLD IS EXPECTED TO LAST THROUGH THE FIRST HALF OF THE NEXT WEEK
AS THE ENSEMBLE CLUSTER ANALYSIS ARE SHOWING THE THE LONGWAVE TROUGH
REMAINING OVER THE CENTRAL CONUS. TEMPERATURES WILL BE VERY COLD
UNDERNEATH THE TROUGH WITH 850MB TEMPERATURES BETWEEN -15 TO -25C
FROM SUNDAY INTO TUESDAY WHICH IS NEAR RECORD LOW VALUES FOR THIS
TIME OF YEAR. THIS MEANS THAT THE CWA WILL STAY BELOW FREEZING UNTIL
WEDNESDAY, WITH SOME SPOTS DROPPING NEAR OR BELOW ZERO ON SUNDAY AND
MONDAY NIGHT AS A SURFACE HIGH MOVES ACROSS THE AREA. CONFIDENCE IN
THE COLD IS FAIRLY HIGHS AS THE NBM IQR FROM SUNDAY TO TUESDAY AT
STL IS 3-7F. WILL NEED TO MONITOR THE POTENTIAL FOR A COLD WEATHER
ADVISORY AS LREF PROBABILITIES ARE SHOWING 30-70 PERCENT CHANCE OF AOB
-10F APPARENT TS EARLY ON MONDAY AND TUESDAY MORNINGS ALONG AND
NORTH OF I-70. WHILE THIS WILL BE A COLD AIRMASS, WE ARE NOT
EXPECTING TO BREAK RECORD LOWS WHICH ARE WELL BELOW ZERO.
TEMPERATURES WILL BEGIN TO MODERATE BY MID-LATE NEXT WEEK AS THE
TROUGH BEGINS TO MOVE OFF TO THE EAST AND THE LOW LEVEL FLOW TURNS
OUT OF THE SOUTHWEST.
NEXT WEEK LOOKS TO BE DRY AT THIS POINT AS THE LONGWAVE TROUGH WILL
DISPLACE THE SURFACE FRONT AND AVAILABLE MOISTURE WELL TO OUR SOUTH
ALONG WITH THE UPPER JET. BOTH THE NBM AND LREF ARE SHOWING THE
MAJORITY OF THEIR MODELS ARE DRY (PROBABILITIES AOB 15%) OVER OUR
AREA.
BRITT
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1045 PM CST THU JAN 16 2025
CALM CONDITIONS HAVE ALLOWED THE TEMPERATURE TO DROP TO NEAR THE
DEWPOINT ESPECIALLY IN THE ST LOUIS METRO AND EASTWARD. THERE
REMAINS THE POTENTIAL FOR FOG DEVELOPMENT IN FAVORED VALLEY
LOCATIONS TONIGHT, ALTHOUGH CONFIDENCE REMAINS TOO LOW TO INCLUDE
IN THE TAF AT THIS TIME. IF IT WERE TO OCCUR IT IS MOST LIKELY AT
SUS OR CPS. OTHERWISE VFR CONDITIONS ARE EXPECTED WITH WINDS
TURNING SOUTHERLY BY MORNING. INCREASING MOISTURE THROUGH THE DAY
FRIDAY WILL LEAD TO INCREASING CLOUDS AND SOME RAIN MOVING
THROUGH SOUTHERN PORTIONS OF THE AREA FRIDAY EVENING. WITH LOW
LEVEL MOISTURE BEING HIGH, WE MAY SEE BROADER VISIBILITY
REDUCTIONS FROM SNOW MELT AND RAIN FRIDAY EVENING BEFORE A COLD
FRONT MOVES IN FROM THE NORTHWEST THROUGH THE NIGHT. THIS FRONT
WILL SHIFT WINDS TO THE NORTHWEST AND BRING A COLDER AND DRIER AIR
MASS, ENDING ANY RAIN AND FOG FAIRLY ABRUPTLY AS IT ARRIVES.
KIMBLE
LSX WATCHES/WARNINGS/ADVISORIES
MO...NONE.
IL...NONE.
WFO LSX
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