000
FXUS63 KEAX 200927
AFDEAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
427 AM CDT SAT MAR 20 2010
.DISCUSSION...
VIGOROUS WINTER STORM ONGOING ACROSS PORTIONS OF THE PLAINS AND
MIDWEST EARLY THIS MORNING. LATEST RADAR TRENDS DEPICTING WAA PRECIP
SHIELD ACROSS THE FORECAST AREA STEADILY MOVING EAST WITH TIME. COLD
AIR HAS BEEN A BIT SLOW TO ADVECT ACROSS THE ENTIRE CWA BUT APPEARS
AREAS ALONG AND NORTH OF A MACON TO BUTLER LINE HAS NOW TRANSITIONED
TO ALL SNOW. AHEAD OF THIS LINE...THE TRANSITION AREA HAS PRODUCED A
DECENT DOSE OF RAIN...FREEZING RAIN AND SLEET AS IT PROPAGATED ACROSS
THE FORECAST AREA. WITH COLD AIR STEADILY PROGRESSING SOUTHWARD
NOW...APPEARS MOST LOCATIONS SHOULD BE COLD ENOUGH FOR SNOW BY
SUNRISE. HOWEVER...BIGGEST CONCERN IS WHETHER THERE WILL BE MUCH SNOW
AROUND BY THE MORNING HOURS.
ISENTROPIC ASCENT...WHICH IS MOST PROMINENT ON THE 290K SFC...SHIFTS
EAST WITH NEUTRAL LIFT DEVELOPING BY THE MORNING HOURS WITH THE NORTHERN AND
WESTERN PORTIONS OF THE CWA UNDER ISENTROPIC DOWNGLIDE. LATEST RADAR
TRENDS SUPPORT THIS IDEA WITH DECREASING ACTIVITY ACROSS NORTHWESTERN
MISSOURI AND NORTHEASTERN KANSAS AS THE MORE CONCENTRATED AREA OF
PRECIPITATION SHIFTS EAST. BELIEVE HIGHEST POPS THROUGH THE MORNING
HOURS WILL REMAIN ACROSS THE EASTERN PORTIONS OF THE CWA BEFORE THIS
AREA SHIFT EAST.
NEW AREA OF PRECIPITATION HAS RECENTLY BLOSSOMED ACROSS CENTRAL
OKLAHOMA AND THIS WILL BE THE NEXT ROUND TO AFFECT THE AREA LATER
TODAY. VIGOROUS 100+ KT H25 JET WILL BEGIN ROUNDING THE BASE OF
DEEPENING UPPER TROUGH TODAY AS IT SHIFTS INTO THE SOUTHERN PLAINS.
AS THIS OCCURS...PRECIPITATION WILL LIKELY BECOME MORE WIDESPREAD
FROM CENTRAL OKLAHOMA NORTHWARD INTO CENTRAL MISSOURI...LIKELY
SOMEWHERE ALONG AND SOUTH OF A KANSAS CITY TO KIRKSVILLE
LINE...ALTHOUGH EXACT POSITION IS STILL UNCERTAIN. AS THE SYSTEM
STRENGTHENS...DYNAMICAL LIFT ALONG WITH INCREASING ISENTROPIC ASCENT
SHOULD LEAD TO ENHANCED PRECIPITATION BY THE MID TO LATE AFTERNOON
HOURS...INTO THE EVENING. THIS PRECIP SWATH IS EXPECTED TO DEVELOP
INTO THE MAIN DEFORMATION BAND DURING THIS TIME FRAME BRINGING
ANOTHER DOSE OF SNOWFALL TO THE AREA. CURRENT THINKING IS THIS ROUND
WILL ALIGN ACROSS THE SOUTHERN CWA...MAINLY SOUTH OF THE MISSOURI
RIVER...ALTHOUGH MAIN SNOW SWATH MAY EXTENT FURTHER NORTH ACROSS
PORTIONS OF CENTRAL MISSOURI..TOWARDS THE MACON AND MOBERLY AREA.
SYSTEM BECOMES BETTER ORGANIZED BY OVERNIGHT TONIGHT AND INTO THE
EARLY MORNING HOURS AS SURGE OF RICH THETA E AIR MASS IS INGESTED
INTO THE SYSTEM. THIS SHOULD LEAD TO A DECENT TROWAL FEATURE
DEVELOPING BY SUNDAY MORNING. AS THIS OCCURS...DEFORMATION BAND IS
EXPECTED TO GRADUALLY WEAKEN AND ANY PRECIP MAY EVEN TRANSITION TO A
MIX OF RAIN/SNOW/SLEET DURING THE DAY SUNDAY AS WARM AIR NOSES INTO
THE ATMOSPHERIC COLUMN. PRECIP IS EXPECTED TO WIND DOWN BY SUNDAY
AFTERNOON AS THE SYSTEM DEPARTS TO THE EAST.
AS FAR AS HEADLINES GO...WILL CANCEL THE ADVISORY FOR THE FAR
NORTHWEST CORNER OF MISSOURI AS SNOWFALL HAS LIGHTENED OR ENDED
ACROSS MOST AREAS. ALSO...ADDED HOWARD AND COOPER COUNTIES INTO THE
ADVISORY WITH SNOW EXPECTED TO INCREASE THROUGH THE DAY ACROSS THOSE
AREAS. OTHERWISE...REGROUPED THE COUNTIES A BIT FOR BETTER TIMING.
DEROCHE
&&
.AVIATION...
FOR THE 06Z TAFS...TIMING OF BACK EDGE OF BAND OF HEAVY SNOW
CURRENTLY IN SOUTH CENTRAL KANSAS...WOULD SUGGEST VSBYS AND CIGS
SHOULD START TO IMPROVE AT THE KANSAS CITY TERMINALS BETWEEN 09 AND
11Z. KSTJ IMPROVEMENT MAY BE A LITTLE SOONER SINCE THIS HEAVY BAND
IS ALSO SHIFTING TO THE SOUTHEAST. KSTJ WILL BE RESIDING ON THE
NORTHERN FRINGES OF THE SNOW ON SATURDAY...SO WILL GO WITH HIGHER
VSBYS AND CIGS AT THAT SITE. KANSAS CITY TERMINALS MAY SEE ANOTHER
ROUND OF BETTER LIFT BY MIDDAY WITH SOME MID LEVEL WAA...SO WILL
TEMPO IN ANOTHER GROUP OF MORE MODERATE SNOW DURING THIS TIME FRAME.
PC
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...WINTER WEATHER ADVISORY UNTIL 1 PM CDT SUNDAY FOR MOZ025-031>033-
038>040-046.
WINTER STORM WARNING UNTIL 1 PM CDT SUNDAY FOR MOZ043>045-053-
054.
WINTER WEATHER ADVISORY UNTIL 7 PM CDT THIS EVENING FOR
MOZ003>006-012-013-020.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT SUNDAY FOR MOZ007-008-
014>017-021>024-028>030-037.
KS...WINTER STORM WARNING UNTIL 1 PM CDT SUNDAY FOR KSZ057-060.
WINTER WEATHER ADVISORY UNTIL 7 PM CDT THIS EVENING FOR KSZ025-
102.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT SUNDAY FOR KSZ103>105.
&&
$$
