Area Forecast Discussion
Issued by NWS St. Louis, MO

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KLSX 252052
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
352 PM CDT SAT JUL 25 2015

.SHORT TERM: (TONIGHT AND SUNDAY)
ISSUED AT 348 PM CDT SAT JUL 25 2015

WILL ISSUE A FLASH FLOOD WATCH TONIGHT FOR MUCH OF NORTHEAST
MISSOURI AND WEST CENTRAL ILLINOIS AS I EXPECT A MCS TO MOVE ACROSS
THE AREA LATER THIS EVENING INTO THE OVERNIGHT HOURS.  NAM AND GFS
MASS FIELDS SEEM TO SUPPORT THE IDEA OF STRONG MOISTURE CONVERGENCE
DEVELOPING DURING THE EVENING OVER NORTHERN MISSOURI WHICH WILL
LIKELY SUPPORT THE DEVELOPMENT OF A MCS.  PROPOPATION VECTORS FAVOR
THIS MCS MOVING ACROSS NORTHERN MISSOURI BEFORE TURNING
SOUTHEASTWARD NEAR THE MISSISSIPPI RIVER LATE TONIGHT.  THIS IS
SUPPORTED BY 12Z NMM-WRF CAM. PWATS ARE VERY HIGH WITH VALUES
OVER 2.0 INCHES CONTINUING TO SUGGEST THAT RAINFALL WILL BE
POTENTIALLY HEAVY. HAVE GONE WITH A FLASH FLOOD WATCH FOR THIS
REASONING.

THE MCS WILL BE DECAYING ON SUNDAY MORNING...BUT WILL STILL INCLUDE
LIKELY POPS ON SUNDAY MORNING OVER PART OF THE AREA AS IT MOVES
SOUTHEAST.  LIKE TODAY...THE CLOUDS AND MORNING RAIN MAY TEMPER THE
RECOVERY IN TEMPERATURES WHICH WILL HAVE AN IMPACT IN WHETHER WE
WILL BE ABLE TO REACH HEAT INDEX CRITERIA.  FEEL THAT THE ONLY AREA
THAT I AM CONFIDENT IN ENOUGH AT THE MOMENT THAT WE WILL REACH
CRITERIA IS OVER CENTRAL MISSOURI. THERE WILL ALSO BE SOME POTENTIAL
FOR ADDITIONAL SCATTERED THUNDERSTORMS AT THE ATMOSPHERE BECOMES
UNCAPPED AND UNSTABLE DURING THE AFTERNOON.

BRITT

.LONG TERM:  (SUNDAY THROUGH NEXT SATURDAY)
ISSUED AT 348 PM CDT SAT JUL 25 2015

(SUNDAY NIGHT THROUGH TUESDAY)

THIS WILL BE A WARM PERIOD AS THE SURFACE FRONT REMAINS WELL TO THE
NORTH AND HIGH TEMPERATURES CLIMB INTO THE LOW-MID 90S.  THE
DEWPOINTS WILL BE WELL INTO THE 70S ALLOWING HEAT INDICES TO CLIMB
ABOVE 100 EACH DAY. WILL LIKELY NEED TO EXTEND AND EXPAND THE HEAT
ADVISORY DURING THIS PERIOD. RAIN CHANCES DO NOT LOOK AS HIGH AS AN
UPPER HIGH BUILDS OVER THE AREA.

(WEDNESDAY THROUGH SATURDAY)

ECMWF AND GFS ARE IN RELATIVELY GOOD AGREEMENT THAT A COLD FRONT
WILL MOVE THROUGH THE AREA ON WEDNESDAY AS THE UPPER PATTERN BEGINS
TO AMPLIFY OVER THE COUNTRY.  WILL CARRY A CHANCE OF SHOWERS AND
THUNDERSTORMS WITH THE PASSAGE OF THE COLD FRONT ON WEDNESDAY, BUT
THEN GO DRY AS NORTHWESTERLY UPPER FLOW SETS UP AS LARGE HIGH SETS
UP OVER THE WESTERN CONUS AND TROUGH DIGS IN THE EAST.  WARMEST DAY
WILL BE AHEAD OF THE FRONT ON WEDNESDAY, BUT THEN THEY WILL FALL
BACK SLIGHTLY BELOW NORMAL FOR THE REST OF THE PERIOD.

BRITT

&&

.AVIATION:  (FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1245 PM CDT SAT JUL 25 2015

WINDS HAVE BEEN HARD TO PIN DOWN DUE TO LEFT OVER AIRMASS FROM
MORNING CONVECTION. BUT SHOULD SEE SITES ALONG I70 CORRIDOR BECOME
SOUTHEAST TO SOUTH WHILE KUIN TO REMAIN NORTH OF A WEAK FRONTAL
BOUNDARY WITH WEST WINDS. THEN BY THIS EVENING WINDS TO BE LIGHT
AND VARIABLE MOST LOCATIONS. BEST CHANCES OF STORMS TO AFFECT TAF
SITES WILL BE IN THE OVERNIGHT HOURS, AFTER 06Z-09Z SUNDAY
TIMEFRAME. FOR NOW JUST HAVE VICINITY THUNDERSTORM MENTION IN.
THEN HAVE BREAK IN ACTIVITY AFTER MID MORNING ON SUNDAY WITH
SOUTHERLY WINDS.

SPECIFICS FOR KSTL:
WINDS HAVE BEEN HARD TO PIN DOWN DUE TO LEFT OVER AIRMASS FROM
MORNING CONVECTION. BUT SHOULD SEE SOUTHEAST WINDS IN METRO AREA
THROUGH THIS AFTERNOON. THEN BY THIS EVENING WINDS TO BE LIGHT
AND VARIABLE. BEST CHANCES OF STORMS TO AFFECT METRO AREA WILL BE
IN THE OVERNIGHT HOURS, AFTER 09Z SUNDAY. FOR NOW JUST HAVE
VICINITY THUNDERSTORM MENTION IN. THEN HAVE BREAK IN ACTIVITY
AFTER 16Z SUNDAY WITH SOUTHERLY WINDS.

BYRD

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...HEAT ADVISORY UNTIL 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.

     FLASH FLOOD WATCH FROM 10 PM CDT THIS EVENING THROUGH SUNDAY
     MORNING FOR AUDRAIN MO-BOONE MO-CALLAWAY MO-KNOX MO-LEWIS
     MO-LINCOLN MO-MARION MO-MONROE MO-MONTGOMERY MO-PIKE MO-
     RALLS MO-SHELBY MO.

     HEAT ADVISORY FROM NOON TO 9 PM CDT SUNDAY FOR BOONE MO-CALLAWAY
     MO-COLE MO-MONITEAU MO-OSAGE MO.

IL...FLASH FLOOD WATCH FROM 10 PM CDT THIS EVENING THROUGH SUNDAY
     MORNING FOR ADAMS IL-BROWN IL-PIKE IL.

&&

$$

WFO LSX


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.