Issued by NWS Springfield, MO
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000 FXUS63 KSGF 050547 AFDSGF AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 1147 PM CST TUE NOV 4 2008 ...UPDATE TO AVIATION... .DISCUSSION... CURRENTLY...ANOTHER PLEASANT DAY HAS BEEN OBSERVED ACROSS THE REGION. UNDER A MAINLY CLEAR SKY...TEMPERATURES HAVE RISEN INTO THE 70S AREA WIDE. SOUTHERLY WINDS HAVE BEEN GUSTY...ESPECIALLY OVER THE WESTERN HALF OF THE AREA. WITH LOW LEVEL RELATIVE HUMIDITY VALUES DIPPING 30 TO 40 PERCENT RANGE...AN ELEVATED FIRE DANGER CONTINUES. TONIGHT AND WEDNESDAY...ENERGETIC SYSTEM OVER THE INNER MOUNTAIN WEST WILL CONTINUE TO GET ORGANIZED AS IT PULLS INTO THE PLAINS STATES. STRONG LOW LEVEL WINDS WILL DEVELOP AHEAD OF THIS SYSTEM...LEADING TO LOW LEVEL WIND SHEAR CONCERNS FOR AVIATION... AND GUSTY WINDS DURING THE DAYTIME WEDNESDAY. GUSTS ABOVE 30 MPH WILL BE COMMON AND LATER SHIFTS WILL NEED TO CONSIDER A WIND ADVISORY FOR WEDNESDAY AFTERNOON NORTH AND WEST OF THE PLATEAU. WITH SOUTHEAST FLOW CONTINUING THROUGH THE OVERNIGHT AND NOT SWITCHING TO SOUTH OR SOUTHWESTERLY UNTIL THE DAYLIGHT HOURS OF WEDNESDAY...DEWPOINTS WILL REMAIN ON THE DRY SIDE IN THE 40S. ONCE THE WINDS SHIFT TO SOUTHWESTERLY AND CONVERGENCE ALONG THE SFC FRONT INCREASES...DEWPOINTS WILL INCREASE INTO THE 50S. WITH HIGHER LOW LEVEL RH VALUES EXPECTED TOMORROW...FIRE WEATHER DANGER WILL SUBSIDE A BIT...THOUGH THE WINDS WILL BE QUITE GUSTY. WARM TEMPS WILL CONTINUE AND RAINFALL WILL LIKELY HOLD OFF MOST...IF NOT ALL OF WEDNESDAY. THIS WILL QUICKLY CHANGE WEDNESDAY NIGHT. WEDNESDAY NIGHT AND THURSDAY...THE 12Z SUITE OF MODELS HAVE OFFERED LITTLE CHANGE TO THE EXPECTED SENSIBLE WEATHER. CONVECTION IS EXPECTED TO DEVELOP WITHIN A NARROW LOW LEVEL MOISTURE TONGUE ALONG AND AHEAD OF THE SFC COLD FRONT OVER CENTRAL/EASTERN NEB/KS/OK. DISCRETE CELLS WILL BE POSSIBLE AT ONSET...HOWEVER KINEMATIC FIELDS WILL QUICKLY BECOME ORIENTED SUCH THAT A STRONGLY FORCED SQUALL LINE WILL CONGEAL ALONG THE FRONT. THIS LINE SHOULD ENTER WESTERN ZONES DURING THE EVENING AND SPREAD EASTWARD WITH TIME...LIKELY MOVING OFF THE SFC FRONT AS THE LINE WILL HAVE A FORWARD PROGRESS OF AROUND 40KT. 0-6KM BULK WIND SHEAR WILL INCREASE RAPIDLY TO 60 TO 70KT...WITH A 50KT LOW LEVEL JET EXPECTED. TO SAY THE LEAST...THIS SYSTEM WILL BE ENERGIZED. STRONG KINEMATICS ASIDE THOUGH...MOISTURE AND INSTABILITY WILL NOT BE OVERLY IMPRESSIVE. MAX DEWPOINTS IN THE MID/UPPER 50S ARE CERTAINLY MORE THAN CAPABLE TO SUPPORT CONVECTION...HOWEVER IT WILL LIMIT MLCAPE TO 1000 J/KG DURING THE LATE AFTERNOON/EVENING...LESSENING WITH TIME HEADING INTO THE OVERNIGHT. THE PRIMARY SEVERE WEATHER RISK WILL BE DAMAGING WINDS...THOUGH LOW LEVEL WIND SHEAR WILL CERTAINLY POSE A RISK OF A FEW EMBEDDED TORNADOES. THE GREATEST RISK OF SEVERE STORMS WILL BE ALONG/WEST OF THE HIGHWAY 65 CORRIDOR WHERE THE SYSTEM WILL INTERACT WITH THE BETTER INSTABILITY DURING THE EVENING HOURS. WITH TIME... INSTABILITY WILL WANE AND THIS WILL RESULT IN A GRADUAL DECREASE IN THE RISK FOR SEVERE WEATHER AS THE LINE MOVES INTO THE EASTERN HALF OF THE AREA DURING THE OVERNIGHT HOURS. THE LINE SHOULD SURVIVE THROUGH THE AREA...HOWEVER IT IS POSSIBLE THAT THE EXCESSIVE SHEAR MAY COMPROMISE THE AREAL EXTENT OF THE CONVECTION. THIS SYSTEM WILL REMAIN PROGRESSIVE AND SHOULD EXIT STAGE EAST DURING THE DAYLIGHT HOURS OF THURSDAY MORNING. CAA REGIME WILL SET UP DURING THE DAY THURSDAY AND TEMPERATURES WILL BEGIN TO FEEL A BIT MORE LIKE EARLY NOVEMBER. FRIDAY AND SATURDAY...THE PARENT UPPER LOW WILL SLOWLY MOVE THROUGH THE UPPER MIDWEST INTO THE GREAT LAKES. CYCLONIC FLOW WILL MAINTAIN PERIODIC BOUTS OF CLOUD COVERAGE AND MAYBE A FEW SPRINKLES ACROSS CENTRAL MISSOURI. 925/850MB TEMPS WILL FALL TO NEAR 0C AND CONDITIONS WILL BE MUCH COOLER THAN THE PAST SEVERAL DAYS. HIGHS WILL BE IN THE 40S/50S AND LOWS IN THE 30S. SUNDAY ONWARD...THE UPPER PATTERN WILL REMAIN ENERGIZED AND ANOTHER DISTURBANCE IS SLATED TO AFFECT THE REGION EARLY NEXT WEEK. FIVE WAVE CHARTS ARE SUPPORTIVE OF DIGGING ENERGY IN THE NATIONS MIDSECTION...AND WILL NEED TO WATCH A FEATURE THAT WILL DIVE INTO THE DESERT SOUTHWEST AND THEN LIFT NORTHEASTWARD THROUGH THE SOUTHERN PLAINS AND LOW MS RIVER VALLEY REGION. THE GFS/ECMWF ARE INDICATING A MORE WINTER-ESQUE STORM TRACK...CONDUCIVE FOR A COLD RAIN RATHER THAN SEVERE WEATHER. TEMPS FROM SUNDAY ONWARD WILL BE BELOW TO WELL BELOW AVERAGE. GAGAN && .AVIATION... FOR THE 0600 UTC KSGF/KJLN TAFS...STRONG LOW PRESSURE OVER THE CENTRAL PLAINS WILL CONTINUE TO PRODUCE STRONG LOW LEVEL WINDS AND WILL KEEP THE MENTION OF LOW LEVEL WIND SHEAR IN BOTH TAFS THROUGH MID MORNING. STRONG SFC WIND GUSTS WILL INCREASE AS MIXING INCREASE THE DEPTH OF THE MIXED LAYER ON WED WITH GUSTS OVER 30KTS POSSIBLE. THE APPROACHING FRONT WILL BEGIN TO PRODUCE LOWER VFR OR MVFR CEILINGS BY LATE WED EVENING OVER SOUTHEAST KS AND PARTS OF WESTERN MISSOURI WITH INCREASING CHANCES FOR THUNDERSTORMS. DSA && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$
