981
FXUS63 KLSX 260859
AFDLSX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAINT LOUIS MO
259 AM CST SUN JAN 26 2025
KEY MESSAGES
- IT WILL BE COOL TODAY, BUT MILD TEMPERATURES RETURN TOMORROW AND
LAST THROUGH MIDWEEK.
- PRECIPITATION CHANCES INCREASE TOWARD THE END OF THE WEEK, WITH
THIS MOST LIKELY TO FALL AS LIGHT RAIN.
SHORT TERM
(THROUGH LATE MONDAY AFTERNOON)
ISSUED AT 257 AM CST SUN JAN 26 2025
COOL HIGH PRESSURE IS SETTLING SOUTH OUT OF THE CENTRAL PLAINS TODAY
WITH COLD ADVECTION USHERING IN COOLER TEMPERATURES THAN WE SAW
YESTERDAY. IT'S CERTAINLY NOT A BRUTAL COLD BY RECENT STANDARDS, BUT
IT WILL BE NOTICEABLY COOLER THAN YESTERDAY BY ABOUT 10 TO 15
DEGREES. THERE WILL BE A FAIR AMOUNT OF HIGH LEVEL CLOUDS PUSHING
EAST ACROSS THE REGION TODAY AS HIGH LEVEL MOISTURE ASSOCIATED WITH
A WEAK SHORTWAVE TROUGH ALOFT TRACKS EAST THROUGH THE REGION. THESE
CLOUDS BEGIN TO CLEAR OVERNIGHT TONIGHT AS HIGH PRESSURE SETTLES
SOUTH OF THE REGION. WITH CLOUDS CLEARING AND AT LEAST A PERIOD OF
LIGHT OR CALM WINDS, WE'LL SEE BETTER RADIATIONAL COOLING CONDITIONS
TONIGHT THAN WE SAW THIS MORNING. THUS SETTING TONIGHT UP TO BE THE
COLDEST NIGHT OF THIS FORECAST. DEWPOINTS IN THE TEENS SUGGEST THAT
COLD SPOTS WILL LIKELY REACH THESE LEVELS WHILE THE WARMER URBAN
AREAS STAY IN THE 20S. WESTERLY WINDS BEGIN TO PICK UP FROM NORTH TO
SOUTH BY MORNING AS THE HIGH SETTLES SOUTHWARD AND WE FIND OURSELVES
TO ITS NORTH FOR MONDAY.
WITH THE HIGH SETTLING SOUTH TOWARD THE GULF COAST ON MONDAY, WEST
TO SOUTHWEST FLOW WILL DEVELOP OVER OUR REGION INITIATING A REBOUND
IN TEMPERATURES. SOUTHWEST FLOW OFF THE OZARKS WILL AID IN MIXING,
MAKING IT EASIER TO REACH THOSE WARMER TEMPERATURES AND LOWER
DEWPOINTS. WITH THE PRESSURE GRADIENT INCREASING THROUGH THE DAY AS
A COLD FRONT DROPS SOUTHWARD IN THE UPPER MIDWEST, WINDS WILL BECOME
NOTICEABLY BREEZY ESPECIALLY ACROSS THE NORTHERN PART OF OUR
FORECAST AREA. THE COMBINATION OF DRY CONDITIONS, BREEZY WINDS, AND
DRY DORMANT VEGETATION WILL LIKELY LEAD TO ELEVATED FIRE DANGER
CONDITIONS IN PARTS OF THE REGION. THE LOWEST HUMIDITY WILL BE IN
THE SOUTH WITH THE STRONGEST WINDS IN THE NORTH, BUT THERE IS LIKELY
TO BE ENOUGH OF AN OVERLAP ESPECIALLY IN THE MIDDLE TO REACH KEY
THRESHOLDS FOR ELEVATED FIRE DANGER. WHILE WE HAVE HAD SNOW ON THE
GROUND FOR AN EXTENDED PERIOD OF TIME, MUCH OF THIS HAS MELTED IN
RECENT DAYS, AND THERE ARE MANY POCKETS OF DRIER VEGETATION
ESPECIALLY WHERE THE SNOW HAS BEEN GONE FOR LONGER. THESE AREAS WILL
BE PRONE TO MORE RAPID FIRE SPREAD IF A FIRE WERE TO START.
KIMBLE
LONG TERM
(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 257 AM CST SUN JAN 26 2025
THE MAIN FEATURES IN THE LONG RANGE FORECAST ARE A BROAD AND
DEEPENING TROUGH OVER THE EASTERN US, A RIDGE OVER THE NORTHERN WEST
COAST OF NORTH AMERICA, AND A CUT OFF LOW OVER THE SOUTHWEST US. THE
NORTHWEST FLOW BETWEEN THE EASTERN RIDGE AND THE WESTERN TROUGH WILL
FEATURE SEVERAL EMBEDDED SHORTWAVE TROUGHS AND ASSOCIATED COLD
FRONTS WITH MOISTURE REMAINING SUPPRESSED TO THE SOUTH BY PERSISTENT
HIGH PRESSURE NEAR THE GULF COAST. WHEN THE CUT OFF LOW OVER THE
SOUTHWEST EVENTUALLY MOVES EAST, IT WILL FINALLY TAP SOME GULF
MOISTURE AND BRING OUR NEXT CHANCE OF PRECIPITATION, LIKELY IN THE
FORM OF RAIN.
THE FIRST SHORTWAVE TROUGH TO ROTATE AROUND THE BROADER EASTERN
TROUGH MOVES THROUGH THE GREAT LAKES MONDAY NIGHT, SENDING A FRONT
SOUTHWARD BEHIND IT. WHILE THIS DOES BRING SOME INITIALLY COOLER
TEMPERATURES INTO OUR REGION, THE FRONT WASHES OUT QUICKLY AND WARM
ADVECTION RETURNS AGAIN ON WESTERLY FLOW FAIRLY QUICKLY ON TUESDAY.
SO MOST OF US WILL BE EVEN WARMER TUESDAY THAN WE ARE ON MONDAY. WE
REMAIN DRY AS WELL, WITH GULF MOISTURE REMAINING BLOCKED TO THE
SOUTH. MODEL FORECASTS DEPICT DEWPOINTS RISING INTO THE UPPER 20S TO
LOW 30S DURING THE DAY TUESDAY, BUT THERE'S REASON TO THINK THIS MAY
BE TOO MUCH MOISTENING CONSIDERING THERE'S NO REAL MOIST ADVECTION
IN THE LOW LEVELS. IF DEWPOINTS ARE IN FACT LOWER, THEN WE'LL SEE
ANOTHER DAY OF LOW RELATIVE HUMIDITY, BUT LIGHTER WINDS MAY PREVENT
CONDITIONS REACHING ELEVATED FIRE DANGER THRESHOLDS AGAIN.
THE NEXT SHORTWAVE MOVES THROUGH THE GREAT LAKES TUESDAY INTO
WEDNESDAY, WITH THE ASSOCIATED COLD FRONT MOVING THROUGH OUR AREA ON
WEDNESDAY. THIS ONE WILL HAVE A BIT BETTER PUSH OF COOL AIR BEHIND
IT, BUT THE CORE OF THE COLD HEADS TO OUR EAST. WE'LL SEE MORE OF A
GRADIENT IN TEMPERATURES IN OUR AREA ON WEDNESDAY, WITH NORTHERN
AREAS COOLING BEHIND THE FRONT AND SOUTHERN AREAS STILL NEARLY AS
WARM AS TUESDAY. THE SURFACE HIGH ASSOCIATED WITH THIS AIR MASS
MOVES EAST QUICKLY ON THURSDAY, OPENING US BACK UP TO THE MILD
CONDITIONS AGAIN. WHILE THERE REMAINS SOME UNCERTAINTY ON
TEMPERATURES THURSDAY AND FRIDAY AS NOTED BY CONTINUED SOMEWHAT
LARGE INTERQUARTILE RANGES IN THE NBM, THE TREND HAS BEEN WARMER AS
IT'S BECOMING MORE LIKELY THAT WE ONLY GET A GLANCING SHOT OF COOLER
AIR BEHIND WEDNESDAY'S FRONT.
THE CUT OFF LOW OVER THE SOUTHWEST WILL EVENTUALLY HEAD EAST,
ALTHOUGH WE CONTINUE TO SEE VARIANCE IN GUIDANCE ON HOW QUICKLY THIS
PROGRESSION OCCURS. THIS IS FAIRLY TYPICAL WITH CUT OFF LOWS AS THE
SUBTLE WOBBLING OVER SEVERAL DAYS CAN AFFECT HOW EASILY THE LOW GETS
CAUGHT BACK INTO THE BROADER JET STREAM FLOW. WITH SURFACE HIGH
PRESSURE SPENDING THE FIRST HALF OF THE WEEK NEAR THE CENTRAL GULF
COAST, AN EASTERLY FLOW WILL GRADUALLY BUILD UP MOISTURE OVER TEXAS
AHEAD OF THE ARRIVAL OF THE SOUTHWEST UPPER LOW. SO WHEN IT DOES
FINALLY EMERGE FROM THE SOUTHWEST DESERTS, IT WILL LATCH ON TO
BETTER MOISTURE IN THE PLAINS AND BRING WIDESPREAD PRECIPITATION AS
IT TREKS NEAR THE REGION. FOR MUCH OF OUR AREA THIS WILL BE THE
FIRST MEASURABLE PRECIPITATION IN 3 WEEKS (SINCE JAN 10).
WHILE THERE IS VARIATION ON WHEN THE LOW FINALLY ARRIVES, IT'S
BEGINNING TO LOOK AS IF A FIRST INITIAL SHORTWAVE MOVES EAST ON
THURSDAY WITH THE CORE OF THE UPPER LOW TAKING UNTIL FRIDAY OR
SATURDAY TO FINALLY MOVE THROUGH OUR REGION. THE FIRST WAVE BRINGS
WITH IT THE BULK OF THE WARM/MOIST ADVECTION AND THUS THE MOST
SIGNIFICANT OF THE PRECIPITATION THURSDAY NIGHT INTO FRIDAY. IT'S
UNCLEAR HOW MUCH OF THIS WILL FALL IN OUR AREA AS THE BEST FORCING
WITH THE LOW LEVEL WARM FRONT MAY STAY TO OUR SOUTH. WRAP AROUND
MOISTURE INTO THE UPPER LOW WILL CONTINUE LIGHTER PRECIPITATION
UNTIL IT FINALLY EXITS TO THE EAST. WITH THE TREND TOWARD WARMER
TEMPERATURES (OR AT LEAST LESS COLD TEMPERATURES) IN ADVANCE OF THIS
SYSTEM, CONFIDENCE IS GROWING THAT THIS WILL BE ALL OR PRIMARILY
RAIN FOR OUR AREA. EVEN THE NBM 25TH PERCENTILE (THE LOWER END)
KEEPS TEMPERATURES LARGELY ABOVE FREEZING AS PRECIPITATION BEGINS,
LIMITING THE POTENTIAL FOR FREEZING RAIN AT THE ONSET. THERE WILL
LIKELY BE AN AREA OF SNOW TO THE NORTH OF THE TRACK OF THE UPPER LOW
WHERE GREATER COLD AIR EXISTS TO GET PULLED INTO THE SYSTEM, BUT
THIS IS LIKELY TO REMAIN TO THE NORTHWEST OF OUR FORECAST AREA. ONLY
UP TO 20 PERCENT OF 00Z ENSEMBLE MEMBERS PRODUCE SNOWFALL IN THE
NORTHERN PART OF OUR AREA, COMPARED TO 40 PERCENT JUST 24 HOURS AGO.
KIMBLE
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1031 PM CST SAT JAN 25 2025
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD AS NORTHWEST
WINDS AND HIGH CLOUD COVER PERSIST.
JAJA
LSX WATCHES/WARNINGS/ADVISORIES
MO...NONE.
IL...NONE.
WFO LSX
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