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000
FXUS63 KLSX 171141
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
641 AM CDT FRI MAY 17 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 313 AM CDT FRI MAY 17 2013

THE MAIN FEATURE OF INTEREST TODAY IS THE UPPER LOW WHICH PROFILER
AND WATER VAPOR SUGGEST IS CURRENTLY LOCATED ACROSS EXTREME SRN MO
NEAR WEST PLAINS. THE MODELS ARE IN RELATIVELY GOOD AGREEMENT
TRACKING THE LOW E/NEWD TODAY WITH THE MORE SRN POSITION OF THE
LOCAL WRF AND RUC PREFERRED. THIS TRACK WOULD TAKE THE LOW ACROSS
THE EASTERN OZARKS THIS MORNING AND INTO SRN IL THIS AFTENOON. THE
BIGGEST UNCERTAINTY WITH THIS SYSTEM IS THE N/NW EXTENT OF
PRECIPITATION AND COVERAGE. CLOUD TOPS HAVE BEEN COOLING THE LAST
FEW HOURS IS ASSOCIATION WITH AN INCREASING AMOUNT OF SHOWERS. THE
EXPLICIT GUIDANCE GENERALLY DEPICTS SCATTERED COVERAGE
DIMINISHING WITH NORTHWARD EXTENT. THIS SEEMS REASONABLE AND HAS
BEEN GENERALLY ACCEPTED WITH THE HIGHEST POPS ACROSS SE MO INTO
SRN IL. THE THREAT OF CONVECTION SHOULD INCREASE LATER THIS
MORNING IS ASSOCIATION WITH HEATING AND DESTABILIZATION. THE UPPER
LOW SHOULD BE IN SRN IL BY EARLY EVENING...DEPARTING TO THE EAST
NORTHEAST. ANY PRECIPITATION IN THE WAKE OF THE LOW SHOULD BE
STRONGLY TIED TO HEATING...DISSIPATING DURING THE EVENING.

GLASS

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 313 AM CDT FRI MAY 17 2013

SATURDAY LOOKS LARGELY DRY AS A RIDGE ALOFT BUILDS INTO THE AREA
IN ASSOCIATION WITH OVERALL UPSTREAM AMPLIFICATION. LOW LEVEL WAA
WILL INCREASE AND THIS COMBINED WITH LESS CLOUD COVER WILL RESULT
IN WARMER TEMPERATURES. THE CHANCE OF SHOWERS AND THUNDERSTORMS
WILL RE-ENTER THE PICTURE ON SAT NIGHT IN RESPONSE TO LOW LEVEL
WAA/MCON VIA A SWLY LLJ...BRINGING THE POTENTIAL FOR ELEVATED
ACTIVITY TO THE NORTH OF A SLOWLY LIFTING WARM FRONT. THE HIGHEST
PROBABILIT AT THIS TIME APPEARS TO BE ACROSS NRN MO INT CENTRAL
IL. THERE COULD BE ONGOING/RESIDUAL ELEVATED ACTIVITY NORTH OF THE
WARM FRONT ACROSS NE MO/WEST CENTRAL IL ON SUNDAY MORNING.
OTHERWISE INCREASING SOUTHERLY FLOW AND WAA SHOULD RESULT IN
CONTINUED WARMER TEMPERATURES WITH SOME LOCATIONS PUSHING 90
DEGREES.

A VERY ACTIVE PERIOD WILL BEGIN TO UNFOLD LATE SUNDAY AFTERNOON
AND CONTINUE THROUGH AT LEAST TUESDAY NIGHT AS RATHER DEEP AND
BROAD UPPER TROF/UPPER LOW MOVES SLOWLY EAST AND A SERIES OF SHORT
WAVES EJECT E/NEWD. A MOIST AND VERY UNSTABLE AIR MASS WILL BE IN
PLACE AND THIS COMBINED WITH FAVORABLE DEEP LAYER SHEAR WILL
SUPPORT MULTIPLE SEVERE WEATHER EPISODES OVER A 3 DAY PERIOD
MIGRATING WEST TO EAST ACROSS THE CWA WITH THE MOST ACTIVE PERIOD
FROM MONDAY THROUGH TUESDAY NIGHT.

GLASS

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 621 AM CDT FRI MAY 17 2013

FEW CHANGES WERE MADE TO PREV FORECAST WHICH APPEARS TO BE ON
TRACK. EXPECT CHANCE OF PRECIP TO INCREASE LATE THIS MORNING AND
INTO MID AFTERNOON...MAINLY FOR SUS/CPS. WINDS WILL BE SELY AND
AOB 6 KTS. EXPECT FG/ST TO DEVELOP TONIGHT WITH AMPLE MOISTURE
AND WEAK FLOW. ATTM...EXPECT WORST CONDITIONS AT COU AND
SUS/CPS.

SPECIFICS FOR KSTL...EXPECT MVFR CLOUDS TO AFFECT TERMINAL LATER
THIS MORNING AND INTO THE AFTERNOON. PRECIP CHANCES WILL INCREASE
THRU THE MORNING WITH BEST CHANCES EARLY THIS AFTERNOON. WINDS ARE
EXPECTED TO REMAIN SELY AOB 6 KTS.

TILLY

&&

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

$$

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