898 FXUS63 KDMX 050830 AFDDMX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 330 AM CDT THU JUL 5 2012 .SHORT TERM /TODAY/... MAIN CONCERNS WILL BE THE HOT TEMPS AGAIN TODAY ALONG WITH CHANCES FOR SOME THUNDER THIS MORNING AND AGAIN ACROSS THE NORTH THIS AFTERNOON. MODELS IN GENERAL AGREEMENT WITH FRONT EXPECTED TO DROP TO JUST SOUTH OF THE IAMN BORDER BY LATE AFTERNOON. CURRENT POSITION OF FRONT FROM NEAR KFSD TO CENTRAL MN BUT BEGINNING TO MOVE SOUTH SLOWLY. TEMPS DROPPING SLOWLY OVERNIGHT WHICH IS PRETTY MUCH EXPECTED...AND DO EXPECT ANOTHER RATHER UNCOMFORTABLE DAY THURSDAY. SOME RESERVATIONS ABOUT HOW HIGH TEMPS WILL GET WITH CLOUDS AND CURRENT DEVELOPING ISOLATED THUNDERSTORMS OVER IOWA FROM THE THUNDERSTORM COMPLEX OVER NEBRASKA. CLOUDS AND WEAK WAVE FROM THE NEBRASKA COMPLEX BEING PUSHED EAST WITH THE H700 AND H500 FLOW. IT IS LIKELY THAT CLOUD COVER WILL DIMINISH SOMEWHAT THROUGH THE DAY...BUT STILL EXPECT THAT SOME FILTERED SUN MAY BE THE CASE ACROSS THE NORTH WITH MAINLY SUNNY SKIES IN THE SOUTH. HEADLINES WILL REMAIN THE SAME...BUT TEMPS/HEAT INDEX MAY NOT REACH AS HIGH ACROSS THE NORTH AS EARLIER FORECAST AND SOME ADJUSTMENTS IN HEADLINES MIGHT NEED TO BE MADE LATER THIS MORNING OVER THE NORTH. STILL THE PERSISTENT HEAT WARRANTS THE CONTINUATION OF THE WARNING OVER MOST OF THE AREA. WITH THE BOUNDARY DRAPED ACROSS THE NORTH...DEW POINTS WILL BEGIN TO POOL ALONG THE FRONT. HAVE RAISED THE DEW POINTS OVER NORTHERN IOWA TO THE MID 70S BY MID TO LATE AFTERNOON. THIS WILL PROBABLY MAKE UP FOR ANY DROP IN TEMPERATURE DUE TO ANY CLOUD COVER TODAY. SPC DAY1 OUTLOOK INCLUDES A SLIGHT RISK OF SEVERE WEATHER TO ABOUT HIGHWAY 20. HOWEVER LITTLE IN THE WAY OF BULK SHEAR EXISTS ALONG OR SOUTH OF THE SINKING BOUNDARY LATER THIS AFTERNOON. WITH THAT SAID...FEEL CHANCES FOR SEVERE WEATHER SHOULD REMAIN MAINLY NORTH OF THE BORDER THOUGH SOME STORMS MAY DEVELOP INTO NORTHERN IOWA BY MID TO LATE AFTERNOON WHERE INSTABILITY IS MAXIMIZED ALONG THE BOUNDARY. MAIN THREAT WOULD BE WIND WITH A SMALLER THREAT FOR HAIL DUE TO THE HIGH FREEZING LEVELS AND WARM CLOUD DEPTHS...UNLESS STORMS BECOME MORE ORGANIZED. H850 MOISTURE REMAINS QUITE HIGH OVER NORTHWEST IOWA AND SOUTHERN MN WITH DEW POINTS 15 TO 17C. STORMS THAT DO DEVELOP HAVE THE POTENTIAL FOR SOME HEAVY DOWNPOURS...BUT HYDRO CONCERNS REMAIN SOMEWHAT LIMITED WITH CURRENT RAINFALL DEFICIT. .LONG TERM /TONIGHT THROUGH WEDNESDAY/... RIDGE WILL REMAIN MAIN CONCERN FOR BEGINNING OF EXTENDED. HAVE LEFT PRECIPITATION CHANCES ACROSS THE NORTH FOR TONIGHT. NAM CURRENTLY THE MODEL WITH THE BEST HANDLE ON ONGOING PRECIPITATION AND HINTS AT A SUBTLE LINGERING BOUNDARY ACROSS THE NORTH FOR THE OVERNIGHT HOURS...AND WILL LIKELY BE THE FOCUS FOR SOME PRECIPITATION CHANCES...HOWEVER...BETTER CHANCES APPEAR TO BE FURTHER NORTH INTO MN. RIDGE REMAINS STRONG THROUGH THE END OF THE WEEK...WITH TEMPERATURES VERY WARM UNDER RIDGE. GOOD SOUTHERLY FLOW...AND WAA INCREASES ESPECIALLY ACROSS THE WEST. HAVE KEPT TEMPERATURES NEAR GOING TEMPS...AND HAVE BUMPED UP A BIT. HOWEVER...MODELS ARE HINTING AT DEW POINTS A BIT COOLER...IN THE 60S TO NEAR 70. COULD SEE SOME DECENT DEW POINTS ALONG AND NEAR THE FRONTAL BOUNDARY ACROSS THE NORTH...AND HAVE KEPT DEW POINTS A BIT HIGHER THERE...BUT HAVE GENERALLY TRENDED DEW POINTS DOWN. HOWEVER...HEAT INDEX VALUES WILL BE 100 TO 110 DEGREES ACROSS THE CWA FOR THURSDAY AND FRIDAY BEFORE FRONT PUSHES THROUGH. THEREFORE EXCESSIVE HEAT WARNING REMAINS IN PLACE. PREVIOUSLY MENTIONED FRONTAL BOUNDARY WILL BE TRICKY FOR THE EXTENDED FORECAST...DEPENDING ON LOCATION. CURRENTLY...MODELS KEEP THE BOUNDARY FURTHER NORTH ACROSS THE NORTHERN PLAINS...BUT MORE AGGRESSIVE GFS SOLUTION CONTINUES TO PUSH BOUNDARY SOUTH ACROSS CWA FOR SATURDAY. IF FRONT IS A BIT FURTHER SOUTH NEAR THE MN/IA BOARDER...WILL SEE INCREASED CHANCES FOR PRECIPITATION THROUGH THE END OF THE WORK WEEK...AND COOLER TEMPERATURES NEAR THE FRONT AND WITH CLOUD COVER. HOWEVER...HAVE KEPT FORECAST TRENDING TOWARDS THE ECMWF SOLUTION...WHICH KEEPS FRONTAL PLACEMENT WELL INTO MN THROUGH THE REMAINDER OF THE WEEK. DO NOT HAVE ENOUGH CONFIDENCE TO INCLUDE POP CHANCES UNTIL LATE FRIDAY...AND EVEN THEN MAY BE TOO SOON. BEST CHANCES FOR PRECIPITATION LOOK TO BE SUNDAY WITH OTHER MODELS IN LINE WITH ECMWF SOLUTION TO PULLING FRONT SOUTH SUNDAY. BEHIND BOUNDARY...TEMPERATURES WILL COOL NICELY...WITH HIGHS BACK NEAR NORMAL FOR THE REMAINDER OF THE PERIOD. WITH FRONT CONTINUING TO PUSH SOUTH...WILL KEEP NORTHWESTERLY FLOW OVER CENTRAL IOWA FOR THE REMAINDER OF THE PERIOD. AGAIN...THIS WILL HELP KEEP TEMPERATURES NEAR NORMAL. IN ADDITION...COULD SEE CHANCES FOR PRECIPITATION WITH SHORT WAVES PUSHING THROUGH THE FLOW. HOWEVER...MODELS DO NOT HAVE A GOOD HANDEL ON THESE SYSTEMS...AND TIMING IS INCONSISTENT. HAVE THEREFORE OPTED FOR A DRY REMAINDER OF THE FORECAST...ESPECIALLY WITH LIMITED MOISTURE RETURN IN NW FLOW. && .AVIATION...05/06Z VFR CONDITIONS WILL PERSIST THROUGH THE TAF PERIOD. CONVECTION FROM CENTRAL NEBRASKA WILL CONTINUE TO SPREAD SOME HIGH THIN CLOUDS INTO KFOD AND KMCW OVERNIGHT INTO THE DAY ON THURSDAY...OTHERWISE REMAINING SITES SHOULD STAY MAINLY CLEAR EXCEPT FOR A FEW DIURNAL CU THURSDAY AFTERNOON. SOUTH/SOUTHWESTERLY WINDS WILL BE GENERALLY LIGHT THROUGH THE ENTIRE TAF PERIOD. && .DMX WATCHES/WARNINGS/ADVISORIES... EXCESSIVE HEAT WARNING UNTIL 7 AM CDT SATURDAY FOR ADAIR-ADAMS- APPANOOSE-AUDUBON-BLACK HAWK-BOONE-BREMER-BUTLER-CALHOUN-CARROLL- CASS-CERRO GORDO-CLARKE-CRAWFORD-DALLAS-DAVIS-DECATUR-EMMET- FRANKLIN-GREENE-GRUNDY-GUTHRIE-HAMILTON-HANCOCK-HARDIN-HUMBOLDT- JASPER-KOSSUTH-LUCAS-MADISON-MAHASKA-MARION-MARSHALL-MONROE-PALO ALTO-POCAHONTAS-POLK-POWESHIEK-RINGGOLD-SAC-STORY-TAMA-TAYLOR- UNION-WAPELLO-WARREN-WAYNE-WEBSTER-WINNEBAGO-WORTH-WRIGHT. && $$ SHORT TERM...REV LONG TERM...AWB AVIATION...DEITSCH