941 FXUS63 KEAX 020952 AFDMCI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 255 AM CST TUE MAR 2 2004 .DISCUSSION MAIN CONCERN IS THE TIMING OF THE NEXT THREAT OF PRECIPITATION AND THE THREAT OF A MAJOR PRECIPITATION THREAT ON THURSDAY. LATEST MOISTURE IMAGERY INDICATES A STRONG UPPER LEVEL LOW DIVING SOUTH SOUTHEAST ALONG THE CALIFORNIA COAST. MODELS SIMILIAR IN DROPPING THE SYSTEM INTO THE DESERT SOUTHWEST SOUTHWEST BY 12Z WEDNESDAY WITH A SERIES OF WEAK SHORTWAVES EJECTING NORTHEAST ACROSS THE CENTRAL PLAINS WEDNESDAY THROUGH WEDNESDAY NIGHT. MEANWHILE...A SURFACE FRONT BECOMES STATIONARY ALONG THE RED RIVER VALLEY BY WEDNESDAY MORNING. PREFER SLIGHTLY FASTER AVN WITH THE INITIATION OF WEAK WARM ADVECTION PATTERN NORTH OF THIS BOUNDARY. WEAK ISENTROPIC LIFT GENERALLY FOUND ON THE 290-295K ISENTROPIC SURFACES AND CONFINED TO AREAS ALONG AND SOUTH OF THE I-70 CORRIDOR AFTER MIDNIGHT. ISENTROPIC LIFT ALONG THESE SURFACES CONTINUES THROUGHOUT THE DAY MAINLY ACROSS THE SOUTHERN 2/3RDS OF THE CWA...ALBEIT NOT TOO STRONG. AMOUNTS OF PRECIPITATION SHOULD BE QUITE LIGHT. HAVE SOME CONCERN THAT NORTHERN BRANCH SHORTWAVE PASSING TO THE NORTH MAY CONCENTRATE ISENTROPIC LIFT MAINLY ACROSS THE SOUTHERN ZONES WEDNESDAY NIGHT AND WILL CONCENTRATE HIGHEST POPS ACROSS THAT AREA. PREFER ETA WITH THIS SCENARIO AS BELIEVE AVN A LITTLE TOO BULLISH WITH DEPICTION OF STRONG QPF IN SOUTHWEST MISSOURI. HOWEVER...BY LATE WEDNESDAY NIGHT...ISENTROPIC LIFT IN COMBINATION WITH ELEVATED INSTABILITY DEPICTED BY ETA...SUGGEST POTENTIAL FOR THUNDERSTORMS FOR THE SOUTHERN PORTION OF THE CWA. MAIN CONERN IS THURSDAY WHEN STRONG UPPER SYSTEM LIFTS NORTHEAST OUT OF THE DESERT SOUTHWEST INTO THE CENTRAL AND SOUTHERN PLAINS. A LITTLE TOO SOON ON PARTICULARS ON EXACT TRACK...BUT BOTH ETA/GFS TRACK STRONG UPPER LOW INTO THE CWA THURSDAY AFTERNOON AND THURSDAY EVENING WITH COPIOUS H8 MOISTURE. BASED ON TRACK OF UPPER LEVEL LOW...PREFER SURFACE LOW TRACK OF GFS WITH THE SURFACE LOW FROM EXTREME SOUTHEAST KANSAS LATE THURSDAY AFTERNOON...AND THEN INTO EXTREME NORTHEAST MISSOURI BY MIDNIGHT THURSDAY NIGHT. THE COMBINATION OF STRONG QG FORCING...STRONG WARM AIR ADVECTION NORTH OF THE WARM FRONT...AND HIGH PRECIPITABLE WATER AMOUNTS OF 1 TO 1.5 INCHES MAY LEAD TO A POTENTIAL HYDRO PROBLEM. AT THIS TIME...FEEL BEST THREAT IS ROUGHLY ALONG AND SOUTH OF INTERSTATE 70. WILL ISSUE AN ESF FOR AREAS ALONG AND SOUTH OF INTERSTATE 70. AREA COULD EASILY RECEIVE 1 TO 2 INCHES IN 12 HOURS WITH WOULD EXCEED HEADWATER GUIDANCE. AREA MAY NEED TO BE EXPANDED BASED ON LATER DATA. IN THE SHORT TERM...COLD AIR ADVECTION STRATOCU ASSOCIATED WITH DEPARTING STORM SYSTEM WILL SLOWLY EDGE NORTHEAST TODAY...ONLY TO GIVE WAY TO INCRREASING HIGH CLOUDS. DB && .PREVIOUS DISCUSSION... 320 PM... GETTING RID OF ONE SYSTEM AND GEARING UP FOR THE NEXT. DEEP UPPER LOW CENTERED OVER CENTRAL IA WILL TRACK NORTHEAST TONIGHT WITH LOW LEVEL GRADIENT WEAKENING. THIS WILL RESULT IN DECREASING WINDS LATER THIS EVENING. FROM NOW TILL MID EVENING THE WINDS WILL REMAIN RATHER STRONG AND GUSTY. LOW CLOUDS A BIT TRICKY TONIGHT AND TUESDAY. WRAP AROUND CLOUDS ASSOCIATED WITH 850 MB COLD POOL WILL LIFT NORTHEAST THIS EVENING. HOWEVER...A LOWER DECK TO THE NORTH IS FORECAST BY THE RUC AND ETA 925MB CONDENSATION PRESSURE DEFICIT PROGS TO SURGE SOUTH AT THE SAME TIME THE STRATOCU IS LIFTING NORTHEAST. NET EFFECT...MAY SEE SOME CLEARING FROM THE WEST LATER THIS EVENING SOUTH OF HIGHWAY 36 BUT LOWER DECK FORECAST TO DROP SOUTH AFTER MIDNIGHT...REACHING THE MO RIVER BY 12Z TUE. LOW CLOUDS SHOULD BURN OFF/SHIFT EAST BY TUESDAY AFTERNOON. ETA/MAV MAX TEMPERATURES LOOK REASONABLE. ALTHOUGH NEXT STORM SYSTEM WILL BE OVER NORTHERN MEXICO TUESDAY/TUESDAY NIGHT...STRONG WARM AIR ADVECTION PATTERN EXPECTED TO MOVE INTO EASTERN KS/NORTHERN MO AS SOUTHWESTERLY FLOW ALOFT TRANSPORTS INCREASING MID/UPPER LEVEL MOISTURE INTO THE CENTRAL U.S. HAVE MAINTAINED LOW CHANCE POPS FOR LATE TUESDAY NIGHT OVER FAR SOUTHWEST COUNTIES AS WEAK VORTICITY LOBE SHEARS NORTHEAST. ALTHOUGH THERE ARE SOME DIFFERENCES BETWEEN MODELS ON WEDNESDAY THEY ARE IN AGREEMENT THAT THERE WILL BE AN INCREASING THREAT FOR RAIN IN STRENGTHENING WARM AIR ADVECTION ZONE WELL NORTH OF THE SURFACE WARM FRONT. HAVE BUMPED UP POPS OVER THE SOUTHERN HALF OF THE CWA. HAVE ALSO TIGHTENED THE DIURNAL TEMPERATURE SWING AS CLOUDS/RAIN KEEP READINGS WITHIN A 5-10 DEGREE RANGE. MJ A SOGGY FINISH TO THE WORK-WEEK IS FORECAST...AS MEDIUM RANGE MODELS CONTINUE TO PROG THE EJECTION OF A DESERT SOUTHWEST SHORTWAVE INTO THE SOUTHERN PLAINS AND CENTRAL MISSISSIPPI VALLEY REGIONS. EXPECT SIGNIFICANT PRECIPITATION ACROSS THE REGION THURSDAY AFTERNOON AND NIGHT...AS THE NEGATIVELY TILTED SHORTWAVE AND ASSOCIATED SURFACE FRONT TRACK ACROSS NORTHERN AND CENTRAL MISSOURI. CONVECTION IS ALSO LIKELY IN THE SOUTHERN THIRD OF THE CWA ON THURSDAY...AIDED BY MODERATE LOW-LEVEL MOISTURE CONVERGENCE. THERMAL PROFILES WITH THIS SHORTWAVE APPEAR WARM ENOUGH FOR RAIN FOR THE MOST PART...WITH THE EXCEPTION OF A LOW CHANCE FOR A RAIN/SNOW MIX IN EXTREME NORTHERN MISSOURI ON THURSDAY NIGHT TOWARD THE END OF THE EVENT. HAVE GENERALLY STAYED CLOSE TO GUIDANCE TEMPS...ALTHOUGH THURSDAY NIGHT LOWS MAY NEED TO BE INCREASED IF IT CONTINUES TO APPEAR THAT CLOUD COVER AND DEW POINTS MAY PREVENT TEMPS FROM FALLING OVERNIGHT. LS && .EAX WATCHES/WARNINGS/ADVISORIES... .MO...NONE. .KS...NONE. $$ WFO EAX