916
FXUS63 KLSX 281112
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE SAINT LOUIS MO
512 AM CST TUE JAN 28 2025
KEY MESSAGES
-TEMPERATURES IN THE UPPER 40S TO LOW 50S WILL CONTINUE THROUGH THE
END OF THE WORK WEEK.
-RAIN WILL MOVE INTO THE REGION THURSDAY MORNING AND LAST INTO
FRIDAY, BRINGING AT LEAST 0.5" OF RAIN TO MOST OF THE FORECAST
AREA WITH THE GROWING POTENTIAL FOR OVER AN 1 ACROSS SOUTHEAST
MISSOURI AND SOUTHWEST ILLINOIS.
SHORT TERM
(THROUGH LATE WEDNESDAY AFTERNOON)
ISSUED AT 233 AM CST TUE JAN 28 2025
THANKS TO A WARM DAY YESTERDAY AND ELEVATED SOUTHWESTERLY WINDS
OVERNIGHT, LOW TEMPERATURES THIS MORNING ARE EXPECTED TO BE THE
WARMEST SINCE MID-JANUARY AT COLUMBIA AND QUINCY, AND SINCE DECEMBER
2024 AT ST. LOUIS. THE WARM START, CLEAR SKY, AND ANOTHER DAY OF
SOUTHWEST WINDS WILL HELP TEMPERATURES INCREASE A FEW DEGREES FROM
YESTERDAY WITH HIGHS IN THE UPPER 40S TO LOW 50S ACROSS THE AREA.
OVERNIGHT A COLD FRONT WILL SLIDE EAST TO WEST ACROSS THE UPPER
MISSISSIPPI VALLEY, NEVER MAKING IT INTO THE FORECAST AREA, WHILE AT
THE SAME TIME A SURFACE HIGH WILL PUSH EASTWARD INTO THE MID-
MISSISSIPPI VALLEY. WEDNESDAY WILL PROVIDE ANOTHER SUNNY DAY WITH
ABOVE NORMAL TEMPERATURES SIMILAR TO TUESDAY.
DELIA
LONG TERM
(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 233 AM CST TUE JAN 28 2025
A CUT-OFF MID-LEVEL LOW WILL EXIT THE FOUR CORNERS REGION AND SLIDE
INTO THE MID-MISSISSIPPI VALLEY THURSDAY. THE SURFACE LOW DRIVING
THE LATE WEEK RAINFALL WILL STRENGTHEN IN RESPONSE TO THE
APPROACHING MID-LEVEL CUT-OFF LOW, AND PUSH EAST INTO THE MID-
MISSISSIPPI VALLEY. ONGOING WARM AIR ADVECTION AND A NORTHWARD
LIFTING WARM FRONT WILL HELP KICK OFF PRECIPITATION THURSDAY MORNING
ACROSS SOUTHEAST MISSOURI AND LEND A SHOWERY APPEARANCE TO THE RAIN.
PRECIPITATION WILL SPREAD NORTH AND EAST THROUGH THE DAY AND INTO
THE EVENING, FINALLY EXITING THE FORECAST AREA FRIDAY DURING THE DAY.
GUIDANCE CONTINUES TO HIGHLIGHT STRONG MOISTURE RETURN AHEAD OF THIS
SYSTEM AND THE NAEFS IS HIGHLIGHTING PRECIPITABLE WATER VALUES
LARGELY BETWEEN 1.00-1.25 INCHES, AN INCREASE FROM 24 HOURS AGO.
THIS INCREASE COULD BE ATTRIBUTED TO A NORTHWARD SHIFT IN THE TRACK
OF THE LOW, BRINGING MORE MOISTURE AND BETTER FORCING FOR
PRECIPITATION INTO THE FORECAST AREA. AS THE COLD FRONT ASSOCIATED
WITH THE SURFACE LOW MOVES THROUGH THE SOUTHERN FORECAST AREA
THURSDAY A STRONG LOW-LEVEL JET WILL RUN PARALLEL TO THE FRONT,
INCREASING LIFT ACROSS THIS AREA AND WITH THE POTENTIAL TO PRODUCE
TRAINING PRECIPITATION AND THEREFORE HIGHER QPF.
CONFIDENCE IS HIGH (70+%) THAT MOST OF THE FORECAST AREA WILL SEE AT
LEAST 0.5" OF RAIN, WHILE PORTIONS OF SOUTHEAST MISSOURI AND
SOUTHERN ILLINOIS ARE LIKELY (80-90%) TO SEE OVER AN INCH OF RAIN
WITH THIS SYSTEM. ENSEMBLE GUIDANCE INDICATES A 65% CHANCE OF OVER 2
INCHES OF RAIN WITHIN THE STRONGEST PORTION OF THIS SYSTEM. WHILE
00/01Z GUIDANCE CURRENTLY KEEPS THIS AREA OF HIGHEST QPF TO THE
SOUTH OF THE CWA, IT ILLUSTRATES THE POTENTIAL WITHIN THIS SYSTEM.
ANOTHER NORTHWARD SHIFT IN THE SYSTEM COULD BRING THESE
PROBABILITIES OF 2 INCHES OF RAINFALL WITHIN REACH. THE ONE CAVEAT
WITH THESE GENERALIZED QPF AMOUNTS IS THAT THE RAIN COULD HAVE A
CONVECTIVE COMPONENT (20% CHANCE) TO IT THURSDAY THROUGH THURSDAY
NIGHT GIVEN THE MINOR INSTABILITY CONTINUING TO BE PRODUCED IN THE
GLOBAL ENSEMBLE SYSTEMS (AROUND 100 J/KG OF MUCAPE). WHERE
THUNDERSTORMS OCCUR, UNEVEN PRECIPITATION AMOUNTS ARE POSSIBLE WITH
SOME AREAS RECEIVING LESS PRECIPITATION THAN FORECAST.
WHERE PRECIPITATION EXCEEDS 1 INCH, STREAMS AND RIVERS ARE EXPECTED
TO RESPOND AND COULD RESULT IN RISES TO NEAR MINOR FLOOD STAGE.
CURRENTLY HEFS DATA HIGHLIGHTS THE BLACK RIVER AT ANNAPOLIS AND THE
MERAMEC RIVER AT STEELVILLE WITH THE BEST CHANCE FOR THESE IMPACTS.
HOWEVER, IT WILL DEPEND ON WHICH BASINS SEE THE MOST AMOUNT OF RAIN
AS TO WHERE IMPACTS WILL BE FELT.
THE WEAKENING MID-LEVEL LOW, NOW AN OPEN TROUGH, WILL EXIT THE MID-
MISSISSIPPI VALLEY FRIDAY INTO SATURDAY AND LEAVE ZONAL MID-LEVEL
FLOW IN ITS WAKE. AT THE SURFACE HIGH PRESSURE WILL SCOOT ACROSS THE
REGION THROUGH THE WEEKEND. STRONG SOUTHWESTERLY LOW-LEVEL FLOW WILL
REESTABLISH BY SUNDAY, BRINGING 925 MB TEMPERATURES TO NEAR 10
DEGREES C. THIS WILL RESULT IN HIGH TEMPERATURES IN THE 50S TO NEAR
60 DEGREES F! CONFIDENCE IS GROWING IN THESE BALMY SUNDAY
TEMPERATURES WITH THE 25TH PERCENTILE NEAR TO ABOVE 50 DEGREES F
ACROSS THE FORECAST AREA. HEADING INTO THE FIRST HALF OF THE WORK
WEEK THE MID-LEVEL FLOW PATTERN WILL TRANSITION FROM ZONAL TO MORE
AMPLIFIED, INCREASING THE POTENTIAL FOR MORE ACTIVE WEATHER BEYOND
THE CURRENT SEVEN DAY FORECAST.
DELIA
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 509 AM CST TUE JAN 28 2025
DRY AND VFR FLIGHT CONDITIONS WILL CONTINUE THROUGH THE REMAINDER
OF THE TAF PERIOD. SOUTHWESTERLY WINDS WILL BECOME GUSTY AT MOST
SITES THIS AFTERNOON AND LAST INTO THE EVENING HOURS BEFORE
DIMINISHING. GUIDANCE HAS INDICATED THAT LLWS MAY BECOME A CONCERN
OVERNIGHT BUT SPEEDS AT THE TOP OF THE 2,000 FT LAYER AREN'T HIGH
ENOUGH YET TO WARRANT MENTION.
DELIA
LSX WATCHES/WARNINGS/ADVISORIES
MO...NONE.
IL...NONE.
WFO LSX
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