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000
FXUS63 KLSX 081148
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
548 AM CST Sat Mar 8 2014

.UPDATE:
ISSUED AT 339 AM CST SAT MAR 8 2014

COLD FRONT MAKING ITS WAY ACROSS THE CWA THIS MORNING AT JUST A
SLIGHTLY SLOWER PACE THAT MODELS INDICATED. LOW CLOUDS GRADUALLY
FILLING IN BEHIND THE FRONT. PRECIPITATION HAS BEEN VERY LIMITED
AND LIGHT WITH BEST RADAR ECHOES MOVING INTO NORTHERN ILLINOIS.
PATCH OF RAIN MOVING INTO NE OKLAHOMA SEEMS TO SUPPORT THE MODELS
TREND OF DEVELOPING PRECIPITATION ACROSS THE SOUTHERN HALF OF THE
CWA FROM 18 - 00Z, THUS CURRENT FORECAST TRENDS LOOK GOOD.

JPK

.SHORT TERM:  (THROUGH LATE THIS AFTERNOON)
ISSUED AT 127 AM CST SAT MAR 8 2014

SURFACE COLD FRONT CONTINUES MOVING THROUGH THE CWA TODAY FOLLOWED
BY AN UPPER SHORTWAVE TONIGHT. LIGHT POST-FRONTAL PRECIP IS EXPECTED
TO CONTINUE THIS MORNING ACROSS NORTHEAST MO/WEST CENTRAL IL. LIFT
AHEAD OF THE UPPER SHORTWAVE IS EXPECTED TO SUPPORT A SECOND AREA
OF LIGHT PRECIP THIS AFTERNOON/EVENING, GENERALLY ALONG AND SOUTH
OF THE I-70 CORRIDOR.

KANOFSKY

.LONG TERM:  (TONIGHT THROUGH THURSDAY)
ISSUED AT 127 AM CST SAT MAR 8 2014

HIGH PRESSURE BUILDS IN BEHIND THE COLD FRONT TONIGHT AND TOMORROW,
EVENTUALLY SETTLING SOUTH OF THE CWA ON SUN. LOOK FOR SLIGHTLY
WINDIER CONDITIONS ON SUN AND MON DUE TO THE TIGHTENING PRESSURE
GRADIENT BETWEEN THE ELONGATED SURFACE RIDGE TO THE SOUTH AND A
SURFACE LOW MOVING ALONG THE US/CANADA BORDER TOWARDS THE GREAT
LAKES. BUFKIT PROFILES SHOW THAT STRONGER WINDS ALOFT WILL MIX DOWN
ON MON, CONTRIBUTING TO GUSTY WINDS. THE WARMEST DAYS DURING THE
EXTENDED PERIOD APPEAR TO BE ON MON (STEADY SOUTHWEST WINDS AND
GOOD MIXING) AND TUE (WARM FRONTAL PASSAGE AHEAD OF A POSSIBLE LOW
PRESSURE SYSTEM).

QUASIZONAL FLOW ALOFT PERSISTS THROUGH EARLY NEXT WEEK. MODELS
DEPICT A STRONG SHORTWAVE REACHING THE OR/CA COAST AROUND 12Z MON,
BUT SOLUTIONS DIVERGE THEREAFTER. THIS SYSTEM MIGHT PRODUCE
PRECIPITATION ACROSS THE LSX CWA DURING THE TU-TH TIME FRAME, BUT
CONFIDENCE REMAINS LOW AT THIS TIME DUE TO POOR RUN-TO-RUN
CONTINUITY AND DISAGREEMENTS BETWEEN MODELS.

KANOFSKY

&&

.SHORT TERM:  (THROUGH LATE THIS AFTERNOON)
ISSUED AT 127 AM CST SAT MAR 8 2014

SURFACE COLD FRONT CONTINUES MOVING THROUGH THE CWA TODAY FOLLOWED
BY AN UPPER SHORTWAVE TONIGHT. LIGHT POST-FRONTAL PRECIP IS EXPECTED
TO CONTINUE THIS MORNING ACROSS NORTHEAST MO/WEST CENTRAL IL. LIFT
AHEAD OF THE UPPER SHORTWAVE IS EXPECTED TO SUPPORT A SECOND AREA
OF LIGHT PRECIP THIS AFTERNOON/EVENING, GENERALLY ALONG AND SOUTH
OF THE I-70 CORRIDOR.

KANOFSKY

.LONG TERM:  (TONIGHT THROUGH THURSDAY)
ISSUED AT 127 AM CST SAT MAR 8 2014

HIGH PRESSURE BUILDS IN BEHIND THE COLD FRONT TONIGHT AND TOMORROW,
EVENTUALLY SETTLING SOUTH OF THE CWA ON SUN. LOOK FOR SLIGHTLY
WINDIER CONDITIONS ON SUN AND MON DUE TO THE TIGHTENING PRESSURE
GRADIENT BETWEEN THE ELONGATED SURFACE RIDGE TO THE SOUTH AND A
SURFACE LOW MOVING ALONG THE US/CANADA BORDER TOWARDS THE GREAT
LAKES. BUFKIT PROFILES SHOW THAT STRONGER WINDS ALOFT WILL MIX DOWN
ON MON, CONTRIBUTING TO GUSTY WINDS. THE WARMEST DAYS DURING THE
EXTENDED PERIOD APPEAR TO BE ON MON (STEADY SOUTHWEST WINDS AND
GOOD MIXING) AND TUE (WARM FRONTAL PASSAGE AHEAD OF A POSSIBLE LOW
PRESSURE SYSTEM).

QUASIZONAL FLOW ALOFT PERSISTS THROUGH EARLY NEXT WEEK. MODELS
DEPICT A STRONG SHORTWAVE REACHING THE OR/CA COAST AROUND 12Z MON,
BUT SOLUTIONS DIVERGE THEREAFTER. THIS SYSTEM MIGHT PRODUCE
PRECIPITATION ACROSS THE LSX CWA DURING THE TU-TH TIME FRAME, BUT
CONFIDENCE REMAINS LOW AT THIS TIME DUE TO POOR RUN-TO-RUN
CONTINUITY AND DISAGREEMENTS BETWEEN MODELS.

KANOFSKY

&&

.AVIATION:  (For the 12z TAFs through 12z Sunday Morning)
Issued at 536 AM CST Sat Mar 8 2014

COLD FRONT HAS CLEARED ALL TAF SITES. IFR CIGS PREVIAL FROM
COLUMBIA TO QUINCY AND EXTEND NORTHWEST INTO SOUTHEST IOWA. CLOUDS
WILL HOLD TODAY WITH A GRADUAL LIFTING TO MVFR CONDITIONS. MODELS
SUGGEST SOME FRONTOGENESIS AT 850 AFTER NOON RESULTING IN SOME
LIGHT RAIN ROUGHLY FROM COLUMBIA TO ST. LOUIS ON SOUTH. DRY AIR
FILTERS IN TONIGHT WITH COLUMBIA AND QUINCY CLEAR BY 06Z

Specifics for KSTL:
BIG QUESTION IS WHEN THE LOW CLOUDS WILL ARRIVE AND HOW LOW WILL
THEY BE. SATELLITE NOT MUCH HELP DUE TO ALL THE MID AND HIGH
CLOUDS. DECK HAS BEEN CONSISTENT BELOW 1000 FEET SO WILL GO WITH
900 ABOUT 13Z. SHOULD LIFT TO MVFR WITH SOME LIGHT RAIN THIS
AFTERNOON. GRADUAL CLEARING OVERNIGHT WITH VFR CONDITIONS AFTER
03Z.

JPK

&&

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

$$

WFO LSX