Area Forecast Discussion
Issued by NWS St. Louis, MO

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
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 271952
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
252 PM CDT THU AUG 27 2015

.SHORT TERM:  (THROUGH LATE TONIGHT)
ISSUED AT 251 PM CDT THU AUG 27 2015

THUNDERSTORMS OVER NORTHWEST MISSOURI HAVE BEGUN TO DIMINISH AT
MIDDAY IN AREAL COVERAGE AS LOW LEVEL MOISTURE CONVERGENCE HAS
DIMINISHED IN RESPONSE TO LOW LEVEL JET BACKING.  BELIEVE THAT OUR
AREA WILL STAY DRY THROUGH MOST OF THE NIGHT WITH THE EXCEPTION OF
THE FAR NORTHWESTERN PART OF THE AREA LATE TONIGHT.  BY LATE TONIGHT
WEAK SHORTWAVE TROUGH NOW MOVING ACROSS CENTRAL HIGH PLAINS WILL
MOVE EAST SUPPLYING ASCENT THAT WILL EVENTUALLY MOVE INTO NORTHERN
MISSOURI AFTER MIDNIGHT.  THIS ASCENT IN ADDITION TO THE LEVEL JET
WHICH WILL VEER AGAIN AND WILL PROVIDE ADDITIONAL LOW LEVEL
CONVERGENCE UNDERNEATH THE ASCENT THAT WILL BE ENOUGH FOR
THUNDERSTORM DEVELOPMENT LATER THIS EVENING AND OVERNIGHT OVER IOWA
AND NORTHERN MISSOURI. SO WILL MAINTAIN A SLIGHT CHANCE OF
THUNDERSTORMS LATE TONIGHT OVER NORTHEAST MISSOURI.

A COMPROMISE OF MOS GUIDANCE LOOKS REASONABLE GIVEN THAT THEY ARE
CLOSE TO CURRENT DEWPOINTS WITH CLOUD COVER ALREADY MOVING OVER THE
AREA.

BRITT


.LONG TERM:  (TONIGHT THROUGH WEDNESDAY)
ISSUED AT 345 AM CDT THU AUG 27 2015

TONIGHT THE SURFACE RIDGE CONTINUES TO MOVE OFF TO THE EAST WITH LOW
LEVEL MOISTURE ON THE INCREASE AS NEXT SYSTEM APPROACHES FROM THE
NORTHWEST.  THERE IS A LOT OF DRY AIR TO OVERCOME SO THINK IT WILL
BE DRY WITH JUST AN INCREASE IN MID AND HIGH CLOUDS. LOWS WILL BE
IN THE UPPER 50S TO LOW 60S.

WITH COLD FRONT, UPPER LEVEL SHORTWAVE AND DECENT LOW LEVEL JET
APPROACHING THE REGION ON FRIDAY, WILL SEE PRECIPITATION CHANCES ON
THE INCREASE. BEST CHANCES WILL BE FRIDAY NIGHT THROUGH SATURDAY AS
COLD FRONT SLIDES THROUGH REGION, THOUGH DO NOT EXPECT WIDESPREAD
COVERAGE AS MOISTURE WILL BE LIMITED. HIGHS WILL BE IN THE LOW TO
MID 80S FRIDAY AND SATURDAY WITH OVERNIGHT LOWS IN THE 60S.

FRONT TO WEAKEN AS IT EXITS REGION, WASHING OUT TO OUR SOUTHEAST.
ALSO, SURFACE RIDGE BEHIND FRONT IS RATHER WEAK WITH UPPER LEVEL
RIDGE BUILDING INTO THE CENTRAL PLAINS THROUGH EARLY NEXT WEEK. SO
IT LEAVES OUR AREA IN LIMBO, WITH TEMPERATURES ACTUALLY A BIT WARMER
WITH FRONTAL PASSAGE THROUGH MID WEEK NEXT WEEK. ALSO, WITH WEAK
FLOW OVERHEAD AND WEAK SHORTWAVES SLIDING THROUGH REGION, COULD SEE
ISOLATED/SCATTERED ACTIVITY THROUGH THE REST OF THE FORECAST PERIOD.
FOR NOW WILL KEEP FORECAST DRY UNTIL EXTENDED MODELS GET A BETTER
GRASP ON THE PATTERN THAT WILL EVOLVE OVER REGION. ANOTHER FLY IN
OINTMENT IS WHAT WILL HAPPEN WITH "ERIKA" AS IT APPROACHES THE
SOUTHEASTERN US EARLY NEXT WEEK AND ITS AFFECTS ON THE WEATHER
PATTERN ACROSS OUR REGION.

BYRD

&&

.AVIATION:  (FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1218 PM CDT THU AUG 27 2015

EXPECT MAINLY DRY AND VFR CONDITIONS THROUGH THE TAF PERIOD AS
HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES CONTINUES TO
FEED DRY AIR INTO THE AREA. ONLY EXCEPTION WILL BE IN LOW LYING
AREA LATE TONIGHT INCLUDING KSUS AND KCPS WHERE THERE WILL BE IFR
FOG FORMATION.

SPECIFICS FOR KSTL: EXPECT DRY AND VFR CONDITIONS THROUGH THE TAF
PERIOD.

BRITT

&&

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

$$

WFO LSX



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