Area Forecast Discussion
Issued by NWS St. Louis, MO

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000
FXUS63 KLSX 252239
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
539 PM CDT TUE AUG 25 2015

.SHORT TERM:  (THROUGH LATE TONIGHT)
ISSUED AT 329 PM CDT TUE AUG 25 2015

UNSEASONABLY COOL CONDITIONS WILL CONTINUE TONIGHT AS THE LARGE
SURFACE RIDGE EXTENDING FROM THE EASTERN DAKOTAS SOUTH SOUTHEAST
THROUGH WESTERN MO MOVES VERY SLOWLY EASTWARD.  GOOD RADIATIONAL
COOLING IS EXPECTED TONIGHT NEAR THE AXIS OF THE SURFACE RIDGE DUE
TO A CLEAR SKY...LIGHT NORTHWEST SURFACE WIND...AND SURFACE DEW
POINTS ONLY IN THE UPPER 40S TO LOWER 50S.  LOWS TONIGHT WILL BE
SIMILAR TO THE PREVIOUS NIGHT AND ABOUT 10 TO 15 DEGREES BELOW
NORMAL FOR LATE AUGUST.  THERE MAY BE SOME RIVER VALLEY FOG LATE
TONIGHT DUE TO THE COOL AIR OVER THE WARMER RIVER WATER.

GKS

.LONG TERM:  (WEDNESDAY THROUGH NEXT TUESDAY)
ISSUED AT 329 PM CDT TUE AUG 25 2015

FORECAST TRENDS IN THE LONG TERM WILL ESSENTIALLY REMAIN
UNCHANGED FOR THIS PACKAGE, WITH THE LATEST GUIDANCE CONTINUING TO
INDICATE CANADIAN RIDGE MAINTAINING ITS GRIP ON THE REGION THROUGH
WEDNESDAY EVENING BEFORE IT EXITS AND GRADUALLY BUILDS INTO THE
EASTERN CONUS FOR THE LAST HALF OF THE WEEK. WITH LITTLE CHANGE IN
THE LOW LEVEL THERMAL PROFILE WEDNESDAYS TEMPS SHOULD BE SIMILAR
TO THOSE OF TODAY...WITH A MODEST MODERATION THEN OCCURRING ON
DAYTIME HIGHS THURSDAY-FRIDAY. FOR OVERNIGHT LOWS DON`T THINK THAT
WEDNESDAY NIGHT WILL BE QUITE A COOL AS TONIGHT...BUT WITH
SOUTHEAST PORTION OF RIDGE STILL NOSED INTO SE MO HAVE TRIED TO
EMPHASIZE A FEW SHELTERED AREAS IN THE E OZARKS DIPPING TO AROUND
THE 50 DEGREE MARK. OVERNIGHT LOWS SHOULD BE A CAT OR TWO WARMER
FOR THURSDAY NIGHT DUE TO INCREASED MIXING ALONG WITH THE ARRIVAL
OF SOME CLOUDS OVER OUR NW COUNTIES...BUT LOWS IN THE M-U 50S WILL
LIKELY LINGER FOR ONE MORE NIGHT OVER THE SOUTHEAST HALF OF THE
CWA.

LATEST SOLUTIONS ARE STILL BRINGING A WEAK DISTURBANCE OUT OF THE
SOUTHWEST U.S. AND INTO THE PLAINS ON THURSDAY...WITH THIS SYSTEM
THEN MIGRATING INTO THE MISSISSIPPI VALLEY FRIDAY-SATURDAY.  MODELS
HAVE WOBBLED A BIT WITH TIMING AND LOCATION OF THIS FEATURE...BUT
GIVEN THE RATHER NEBULOUS NATURE OF THIS SYSTEM I THINK THAT THE RUN-
TO-RUN AND MODEL-TO-MODEL CONSISTENCY HAS BEEN SURPRISINGLY GOOD SO
FORECAST WILL CONTINUE TO SPREAD THUNDERSTORM THREAT ACROSS THE
REGION IN THE FRIDAY-SATURDAY TIME FRAME.

FORECAST SPECIFICS BECOME QUITE MUDDLED BY THE START OF NEXT WEEK.
THERE IS GENERAL CONSENSUS THAT RIDGE OVER THE ROCKIES WILL BUILD
INTO THE CENTRAL CONUS..BUT THERE ARE ALSO SOME HINTS THAT A WEAK
SHEAR AXIS WILL DEVELOP FROM THE LOWER OHIO VALLEY INTO THE WESTERN
GULF WITH SOME SUGGESTIONS THAT SURFACE BOUNDARY ASSOCIATED WITH
LATE WEEK SYSTEM BECOMING STATIONARY OVER THE AREA.  AT THIS POINT
WILL GO WITH MODEL CONSENSUS FOR SENSIBLE WEATHER TRENDS...WITH
TEMPS HEADING BACK TOWARDS LATE SUMMER LEVELS AND POPS BELOW CLIMO.

TRUETT

&&

.AVIATION:  (FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 535 PM CDT TUE AUG 25 2015

NORTHWEST FLOW ALOFT WITH A LARGE HIGH PRESSURE SYSTEM AT THE
SURFACE WILL CREATE CONTINUED VFR WEATHER. LIGHT NORTH TO
NORTHWEST WIND FOR WEDNESDAY.

SPECIFICS FOR KSTL: CONTINUED VFR WITH A CLEAR SKY AND A NORTH TO
NORTHWEST WIND FOR WEDNESDAY. AS THE SURFACE HIGH PRESSURE SYSTEM
SLIDES EAST THE WIND WILL BECOME MORE EASTERLY TOWARD THE END OF
THE FORECAST PERILD.

JPK

&&

.PRELIMINARY POINT TEMPS/POPS:
SAINT LOUIS     57  80  60  81 /   0   0   0   0
QUINCY          51  78  55  79 /   0   0   0   0
COLUMBIA        54  80  56  81 /   0   0   0   0
JEFFERSON CITY  52  80  56  81 /   0   0   0   0
SALEM           54  78  56  79 /   0   0   0   0
FARMINGTON      52  77  54  78 /   0   0   0   0

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX



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