Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 251229
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
729 AM CDT SAT JUL 25 2015

.SHORT TERM:  (THROUGH LATE THIS AFTERNOON)
ISSUED AT 515 AM CDT SAT JUL 25 2015

INITIAL CONVECTIVE COMPLEX IS ROLLING THROUGH MID MISSOURI AT
THIS TIME AND DROPPING SOUTH-SOUTHEAST. THIS CONVECTION IS
BEGINNING TO WEAKEN AS IT ENCOUNTERS A MORE STABLE AIRMASS
PRODUCED BY YESTERDAY EVENINGS CONVECTION OVER SOUTHERN MISSOURI.
MEANWHILE...A SECOND COMPLEX HAS WORKED INTO NORTHWEST MISSOURI
OVERNIGHT FROM N KS AND E NE. EXPECT THIS COMPLEX TO FOLLOW A
SIMILAR TREND AS THE FIRST COMPLEX...NAMELY TRACKING SOUTHEAST
WITH TIME AND GRADUALLY DIMINISHING AS IT PROPAGATES AWAY FROM LOW
LEVEL JET AND ENCOUNTERS A SOMEWHAT MORE STABLE AIRMASS.

SO BASED ON ABOVE THINKING...WE ARE ANTICIPATING THAT PRECIP
TREND FOR THE MORNING HOURS WILL BE FOR THE MOST WIDESPREAD
CONVECTION OVER NORTHERN SECTIONS OF THE CWA EARLY ON, WITH
STORMS PROPAGATING SOUTHEAST ACROSS THE FA WITH A GRADUAL DECREASE
OF INTENSITY AND COVERAGE WITH TIME.

LOTS OF UNCERTAINTY ABOUT LOCATION OF STORM REDEVELOPMENT THIS
AFTERNOON. AMS SHOULD BE PLENTY UNSTABLE AND THERE SHOULD BE ONE
OR MORE OLD OUTFLOW BOUNDARIES PRODUCED FROM THIS MORNINGS
CONVECTION, BUT FORECAST SOUNDINGS DO INDICATE A BIT OF CIN
ACROSS THE AREA. HAVE LEFT LOW CHANCE POPS IN ACROSS MOST OF THE
CWA, WITH THE HIGHEST POPS OVER NORTHERN SECTIONS OF THE FA WHERE
MODELS ARE HINTING AT SURFACE BOUNDARY DURING MAX HEATING.

HAVE NOT MADE ANY CHANGES TO HEAT ADVISORY AT THIS POINT.
OBVIOUSLY, THERE IS CONCERN THAT CONVECTION MAY LIMIT HEATING, AND
CURRENTLY SATELLITE PICS INDICATE LOTS OF THICK MID AND HIGH LEVEL
CLOUDS UPSTREAM. HOWEVER ITS STILL VERY EARLY IN THE DAY, AND LOTS
OF TIME FOR CLOUDS TO THIN IN TIME FOR AFTERNOON HEATING.

TRUETT

.LONG TERM:  (TONIGHT THROUGH FRIDAY)
ISSUED AT 515 AM CDT SAT JUL 25 2015

00Z RUNS ARE IN FAIRLY GOOD AGREEMENT THAT A FAIRLY ROBUST
SHORTWAVE WILL BE OVERTOPPING THE UPPER LEVEL RIDGE AND PUSHING
INTO THE MID MISSOURI VALLEY OVERNIGHT TONIGHT. RESULTANT FORCING
OF THE VERY UNSTABLE AND MOIST AIRMASS BY LOW LEVEL JET SHOULD
FUEL ANOTHER ROUND OF CONVECTION...WITH INITIAL DEVELOPMENT OVER
E NE/SW IA THAT SHOULD THEN GROW UPSCALE INTO AN MCS THAT WILL
TRACK SOUTHEAST AND INTO THE LSX CWA. SOLUTIONS DO VARY ON TRACK
OF THIS COMPLEX, BUT THINK GIVEN THE TENDENCIES OF NWP OUTPUT OVER
THE LAST WEEK OR SO BELIEVE THAT THE SOUTHERN SOLUTION OFFERED BY
WPC GUIDANCE MAY BE A VERY GOOD FIRST GUESS.

HEAVY RAIN APPEARS TO BE A GOOD BET ONCE AGAIN TONIGHT AND
POSSIBLY INTO EARLY SUNDAY SINCE PWATS ARE STILL PROGGED TO BE
AROUND 2 INCHES...AND THE ONLY REASON FOR NOT GOING OUT WITH A
WATCH AT THIS POINT WAS DUE TO UNCERTAINLY OF THE TRACK OF THE
COMPLEX. HOWEVER...DID INCLUDE A MENTION OF HEAVY RAIN IN
FORECASTS FOR THOSE AREAS IN THE CWA ROUGHLY ALONG AND NORTH OF
I70 IN MISSOURI.

OVERNIGHT COMPLEX...OR ITS REMNANTS...SHOULD ROLL ACROSS THE CWA
ON SUNDAY MORNING...WITH ADDITIONAL REDEVELOPMENT POSSIBLE IN THE
AFTERNOON AS AMS RECOVERS AND BECOMES UNSTABLE ONCE AGAIN.

HEAT HEADLINES MAY BE NECESSARY TOMORROW DEPENDING AGAIN ON
TIMING OF CONVECTION AND CLOUD TRENDS...AND IT MAY BE THAT THIS
WILL HAVE TO BE A LAST MINUTE CALL FOR TONIGHTS MID SHIFT.
HOWEVER...CRITICAL HEAT INDEX VALUES APPEAR LIKELY HEADING INTO
THE START OF THE WORK WEEK AS UPPER RIDGE INTENSIFIES OVER THE
AREA. WHILE AMS WONT BE TOTALLY CAPPED...THIS INTENSIFICATION OF
THE UPPER RIDGE SHOULD SHIFT THE RING OF FIRE CONVECTION "TRACK"
BIT FURTHER TO OUR NORTH AND EAST...AND PLACE OUR FA IN THE HEART
OF THE WARMER...AND VERY HUMID...AIR.

TONIGHTS MEDIUM RANGE SOLUTIONS ARE STILL INDICATING A FLATTENING
OF THE RIDGE BY THE MIDDLE OF NEXT WEEK WHICH SHOULD ALLOW A COLD
FRONT TO PUSH ACROSS THE AREA. A CHANCE OF STORMS WILL ACCOMPANY
THE COLD FRONT ACROSS THE REGION, BUT COOLER...LESS HUMID...AND
DRIER AIR IS FORECAST ACROSS THE MID-MISSISSIPPI VALLEY BY NEXT
THURSDAY AND FRIDAY.

TRUETT

&&

.AVIATION:  (FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 649 AM CDT SAT JUL 25 2015

SH/TS AFFECTING THE TAF SITES EARLY THIS MORNING SHOULD DIMINISH
THIS MORNING BUT ADDITIONAL STORMS WILL REDEVELOP IN THE HEAT OF
THE AFTERNOON ESPECIALLY NEAR ANY OUTFLOW BOUNDARIES LEFT OVER
FROM THE MORNING CONVECTION. YET ANOTHER THUNDERSTORM COMPLEX IS
EXPECTED TO FORM UPSTREAM OVERNIGHT AND REACH THE TAF SITES AFTER
26/06Z BUT CONFIDENCE IN THE TIMING IS LOW ATTM.

KANOFSKY

&&

.PRELIMINARY POINT TEMPS/POPS:
SAINT LOUIS     92  76  91  76 /  40  50  60  30
QUINCY          89  73  89  72 /  60  60  50  40
COLUMBIA        92  74  91  74 /  60  60  40  20
JEFFERSON CITY  93  75  91  75 /  50  60  40  20
SALEM           89  73  90  73 /  30  40  60  40
FARMINGTON      89  72  90  73 /  30  40  50  30

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...HEAT ADVISORY FROM NOON TODAY TO 7 PM CDT THIS EVENING FOR BOONE
     MO-CALLAWAY MO-COLE MO-CRAWFORD MO-FRANKLIN MO-GASCONADE MO-
     IRON MO-MONITEAU MO-MONTGOMERY MO-OSAGE MO-REYNOLDS MO-
     WARREN MO-WASHINGTON MO.

IL...NONE.
&&

$$

WFO LSX



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