Area Forecast Discussion
Issued by NWS Des Moines, IA
Issued by NWS Des Moines, IA
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243 FXUS63 KDMX 101131 AFDDMX Area Forecast Discussion National Weather Service Des Moines IA 631 AM CDT Mon Jun 10 2024 ...Updated for the 12z Aviation Discussion... .KEY MESSAGES... - Dry weather continues to day, with temperatures in the 70s - On and off showers and storms Tuesday, potentially strong to severe late afternoon to evening - Active weather remains possible at times in the mid to late week, with additional chances for strong to severe storms - Much warmer temperatures expected near the latter half of the work week, with values in the upper 80s to mid 90s && .DISCUSSION... Issued at 358 AM CDT Mon Jun 10 2024 Generally pleasant conditions remain into the start of the work week, as high pressure, currently centered over the Upper Midwest to Southern Canada, continues to descend into the region. Out of a few streaks of high clouds, clear skies can be seen per satellite imagery across most of Iowa, along with light north-northwest winds and fairly comfortable temperatures in the mid 50s to low 60s. Expecting continued dry and quiet weather today as the aforementioned high pressure slowly departs the region through the day. Light winds will remain, largely out of the northwest as weak low level cold air advection streams in the state. Outside of the potential for some cumulus development this afternoon, mostly sunny skies are expected, which will aid to increase temperatures into the mid to upper 70s. Into the evening, the flow pattern is expected to turn more southwesterly, remaining relatively light initially before increasing through Tuesday, along with cloud cover ahead of the next system moving into the area. This system, in the form of a surface low with a frontal boundary extending into Iowa, is expected to bring the next chance for rain into the area. With some moisture return and weak forcing over the region, still not expecting strong to severe storms with this front as it moves across the state. Model guidance seems to hold some disagreement regarding time of arrival, but generally points to around the mid morning time period and continuing into at least the early afternoon. While the NAM and GFS show more saturation within the low levels, the RAP depicts much drier conditions in the low levels which would indicate potential difficulty for precipitation to reach the ground initially, at least. Into the late afternoon to early evening period, some redevelopment of shower and storm activity per CAMS and HRRR guidance is suggested, mainly occurring along and east of I-35. Further environmental analysis shows increased moisture over the area, as well as more appreciable CAPE values around 1000-1500 J/Kg, bulk shear values around 40+ kts and mid-level lapse rates around 7C/km. These conditions would suggest the potential for a few strong to possibly severe storms within this setup, with hail and damaging winds the main threats. This is reflected per an SPC upgrade to a Marginal Risk over northeast Iowa Tuesday afternoon to evening. Winds otherwise will turn more breezy out of the southwest, with gusts up to 20-25 knots while highs reach into the low to mid 80s. The upper level northwest flow is expected to remain throughout the work week, with a thermal ridge further west continuing to build into the region. This will continue to bring much warmer temperatures in the region through the rest of the work week and into the weekend, with highs looking to generally reach into the upper 80s to mid 90s. Given this will be the first wave of hot weather in Iowa this season, please make sure to limit time out in the elements and stay hydrated as necessary. Within the larger scale northwest flow, still seeing the potential for continued periods of more active weather as additional waves track within this larger scale flow. Longer term guidance depicts a frontal boundary tracking across Iowa by Wednesday afternoon to evening, and again Thursday afternoon to evening, though differences are still quite apparent between model members on the evolution, track, and timing of these systems. Generally speaking, moderate CAPE and shear profiles are present over the region, with more appreciable moisture return and the aforementioned warmer temperatures allowing for favorable conditions to put potential strong to severe weather back on the table, along with more appreciable rainfall. Will need to continue to keep a close eye on this more active period, with more details expected to become better known in the coming days. By Friday, high pressure looks to pass through the region, allowing for a period of dry weather before more active weather returns once again into the weekend. Again, more details expected in the coming days. && .AVIATION /12Z TAFS THROUGH 12Z TUESDAY/... Issued at 631 AM CDT Mon Jun 10 2024 VFR conditions are expected throughout the period across all TAF sites. Winds are expected to be light out of the north- northeast, gradually shifting more southeasterly by late this afternoon to evening. Outside of possible cumulus development this afternoon, should see mostly clear skies before more widespread cloud cover arrives from west to east into Iowa after 03z tonight into Tuesday, ahead of possible light rain near the end of the period at KFOD. && .DMX WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Bury AVIATION...Bury