060
FXUS63 KSGF 122010
AFDSGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
310 PM CDT MON MAY 12 2008
DISCUSSION
QUITE WEATHER CONDITIONS PREVAILED ACROSS THE REGION TODAY BEFORE
WE HEAD INTO ANOTHER UNSETTLED WEATHER PATTERN THE REMAINDER OF
THE WEEK. A SOUTHERLY FLOW HAD ALREADY SET UP AS THE SURFACE RIDGE
SHIFTED EAST OF THE MISSISSIPPI RIVER.
THE ACTIVE PATTERN WILL UNFOLD AS AN UPPER TROUGH DIGS INTO THE
DESERT SOUTHWEST OVER THE NEXT 24 HOURS. A MINOR SHORTWAVE WILL
EJECT NORTHEAST FROM THIS SYSTEM INTO THE PLAINS ON TUESDAY WHILE
A FAIRLY STRONG COLD FRONT TAKES SHAPE MOVES INTO EASTERN KANSAS
BY LATE TUESDAY AFTERNOON.
THE LOW LEVEL JET ALREADY GOING OVER THE PLAINS WILL ONLY
STRENGTHEN OVERNIGHT RESULTING INTO INCREASING MOISTURE TRANSPORT
AND WARM AIR ADVECTION ABOVE THE BOUNDARY LAYER. EXPECT TO SEE
ELEVATED CONVECTION TO DEVELOP TUESDAY MORNING ON TH NOSE OF THIS
LOW LEVEL JET AND THE EDGE OF THE DEVELOPING MID LEVEL CAP. IT
APPEARS ELEVATED CONVECTION COULD DEVELOP ACROSS SOUTHERN MISSOURI
TUESDAY MORNING BUT ESPECIALLY OVER CENTRAL MISSOURI. EXPECT
ELEVATED CONVECTION TO SHIFT OFF TO THE EAST DURING THE AFTERNOON.
A FEW OF THESE STORMS COULD PRODUCE MARGINALLY SEVERE HAIL.
MEANWHILE THE AIRMASS WILL DESTABILIZE FARTHER WEST ACROSS EASTERN
KANSAS AND FAR SOUTHWEST MISSOURI. SOME QUESTION REMAINS ON THE
EXTENT OF LOW LEVEL MOISTURE ADVECTION BUT SURFACE DEWPOINTS IN
THE MIDDLE 60S SEEM REASONABLE ALONG THE KANSAS MISSOURI BORDER BY
MID AFTERNOON. ALSO SHEAR PARAMETERS WILL BECOME MORE FAVORABLE AS
A STRONG MID AND UPPER LEVEL JET STREAK INTO THE SOUTHERN PLAINS.
EXISTING CAPPING INVERSION SHOULD BREAK MID TO LATE AFTERNOON WITH
THE INFLUENCE OF THE UPPER JET AND LOW LEVEL MASS CONVERGENCE
ALONG THE SURFACE COLD FRONT. PROGGED SOUNDINGS INDICATE THAT
CELLS WILL QUICKLY BECOME SUPER CELLS OVER SOUTHEAST KANSAS LATE
TUESDAY AFTERNOON. LACK OF DEFINED SURFACE LOW MAY INHIBIT
PRONOUNCED LOW LEVEL BACKING OF THE WINDS BUT LOW LEVEL HELICITIES
WILL STILL BE SUFFICIENT FOR TORNADIC DEVELOPMENT. ANY INCREASE IN
SURFACE DEWPOINTS AND LOW LEVEL WIND SHEAR WOULD INCREASE THE RISK
FOR TORNADOES. SOUNDINGS ALSO SUPPORTIVE OF LARGE HAIL AND
DAMAGING WINDS. THE RISK OF SEVERE WEATHER WILL BE GREATEST WEST
OF HIGHWAY 65 FROM LATE AFTERNOON INTO THE EVENING. THE STORMS
WILL LIKELY TRANSITION TO A SQUALL LINE OR LINE SEGMENTS DURING THE
NIGHT AND GRADUALLY WEAKEN.
THE FRONT WILL SAG THROUGH THE AREA AND STALL OVER OKLAHOMA AND
ARKANSAS WEDNESDAY AS THE PRIMARY UPPER LOW BEGINS TO MIGRATE OUT
OF THE SOUTHWEST U.S. DEVELOPING ISENTROPIC ASCENT AND WARM AIR
ADVECTION OVER THIS BOUNDARY WILL SUPPORT ELEVATED CONVECTION LATER
WEDNESDAY NIGHT INTO THURSDAY. THE PRIMARY RISK FROM THESE STORMS
APPEARS TO BE LARGE HAIL AND HEAVY RAINFALL. IF THE WARM FRONT
MOVES FARTHER NORTH INTO SOUTHERN MISSOURI THEN ALL MODES OF
SEVERE WEATHER WOULD BE POSSIBLE...BUT IT APPEARS THE FRONT WILL
REMAIN TO THE SOUTH.
THE REGION WILL COME UNDER THE INFLUENCE OF A NORTHWESTERLY FLOW
ALOFT AS WE HEAD INTO THE WEEKEND. THIS WILL KEEP TEMPERATURES
NEAR TO BELOW NORMAL. SYSTEMS RIDING THROUGH THIS FLOW COULD BRING
A CHANCE OF SHOWERS BUT TIMING AND STRENGTH OF THESE SYSTEMS IS
VERY DIFFICULT TO DETERMINE AT THIS TIME.
FOSTER
AVIATION
GUSTY SOUTHERLY WINDS WILL CONTINUE TONIGHT AS A COLD FRONT DROPS
INTO THE PLAINS. MID LEVEL CLOUD COVER WILL LIKELY DEVELOP
OVERNIGHT. LOW LEVEL WIND SHEAR MAY ALSO DEVELOP. THE CHANCE OF
SHOWERS AND THUNDERSTORMS WILL DEVELOP TUESDAY. THE COVERAGE AND
INTENSITY OF THE STORMS WILL INCREASE LATER IN THE DAY AS THE COLD
FRONT MOVES EAST INTO THE AREA.
FOSTER
SGF WATCHES/WARNINGS/ADVISORIES
MO...NONE.
KS...NONE.
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