224 FXUS63 KDMX 050445 AFDDMX Area Forecast Discussion National Weather Service Des Moines IA 1145 PM CDT Sat May 4 2019 .DISCUSSION.../Tonight through Saturday/ Issued at 326 PM CDT Sat May 4 2019 Tonight through Sunday...A weak disturbance passing through Iowa is currently over eastern Iowa. In the wake of this wave, a pocket of higher dewpoints near 50 degrees has produced a narrow band of slightly higher instability from northeast Iowa into north central Iowa. Per the NAMNest and NMM hi-res models, which have broken out showers, we indeed have some light showers popping up on radar. Instability and shear are weak so I am not anticipating thunder, or much in the way of rainfall for that matter. However, this mornings light showers were underdone with QPF so while the basin average rainfall will be negligible, local areas may receive several hundredths of an inch. With the loss of heating, any instability will wane. Overnight into Sunday...Another shortwave will trek out of Nebraska into west central Iowa while at the surface, a cold front and surface low will nose into northwest and west central Iowa. Ahead of this, modest theta-e advection and forcing will move into the northwest third of the state. Again weak instability will increase with the theta-e advection...enough for showers and a few thunderstorms to be possible though most of the convection should remain to our west. On Sunday the surface low pushes into northeast Iowa draping the frontal boundary across northern into southwest Iowa. Daytime heating will destabilize the area around the boundary and more widespread showers/storms will develop...especially west central into southwest Iowa. Shear will remain rather weak so while widespread strong are not anticipated, strong forcing in the area would suggest that at least a few storms could be strong with marginally severe hail wind possible mainly west central into southwest Iowa. By Sunday evening the focus will shift south into Missouri and Kansas. Monday and Monday night...While there will be some instability around Monday and light showers cannot be ruled out, the main focus for showers/storms will exist in Missouri, near the boundary. Monday night however, a shortwave will move across southern Iowa/northern Missouri interacting with the boundary and may act to push some of the instability across Missouri back up into southern and possibly central Iowa for additional showers/storms. With weak shear, not really looking at severe potential as that will reside with areas near the boundary. Tuesday will likely be another lull in between systems though a few showers near the Missouri border cannot be ruled out. Tuesday night through Wednesday night will be the interesting period as a deep upper trough lifts out of the intermountain west and across the Plains, finally lifting to the northeast on Thursday. A surface low will develop over the Plains with a frontal boundary extending into the Upper Midwest somewhere gradually lifting across the northwest and central portions of the state Wednesday. Heavy rainfall, and some potential for severe weather will exist on this day however model differences are too large to delineate an area. The system will lift out Thursday with lingering showers through the day before a cooler and drier regime sets in for the rest of the week into Saturday. && .AVIATION.../For the 06Z TAFS through 06Z Sunday night/ Issued at 1145 PM CDT Sat May 4 2019 Small area of showers/thunder over western Iowa weakening with time but may bring a few light showers east toward KDSM between 07 and 10z. Hires models show another area of redevelopment from KFOD to near KMCW and northeast from 07z through 15z. Cigs drop far north at KMCW by 15z to MVFR then return to VFR. A front sagging south will impact KFOD,KDSM,KALO,KOTM with scattered thunder from 18z around KFOD...to near 20-21z KALO/KDSM and near KOTM aft 02z. Cigs behind the boundary again drop to MVFR mainly aft 03z and will leave for next package to refine timing on lower cigs. /rev && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION...FAB AVIATION...REV