Area Forecast Discussion
Issued by NWS Quad Cities, IA IL
Issued by NWS Quad Cities, IA IL
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296 FXUS63 KDVN 280013 AFDDVN Area Forecast Discussion National Weather Service Quad Cities IA IL 713 PM CDT Thu Jun 27 2024 .KEY MESSAGES... - Showers are possible tonight, especially west of the Mississippi River. There is a Slight Risk of severe storms west of a Cedar Rapids to Kahoka Missouri line with a Marginal Risk to the east mainly Friday night. There is also the risk of heavy rainfall Friday - Pleasant weather this weekend. - Active weather returns early next week Monday through Wednesday. - Moderate to Major flooding is expected on several area river. && .SHORT TERM /THROUGH FRIDAY NIGHT/... Issued at 202 PM CDT Thu Jun 27 2024 Surface high pressure is centered over the area early this afternoon. Dewpoints are comfortable in the upper 50s to lower 60s across the area at this time. Air temperatures at 2 PM range from 75 degrees at Dubuque to 81 degrees at Keokuk. There are currently scattered to broken stratocumulus deck across the area. Light precipitation is present on radar west of Interstate 35 but KFOD, KIFA, and KPRO are reporting light rain in central Iowa. Surface high pressure is forecast to move into the eastern Great Lakes tonight as winds at the surface turn to the south with slow moisture advection through the period. Models are showing dry air in the mid levels tonight making the timing of precipitation later despite returns on radar. A 20 to 30 knot low level jet develops this evening across western Iowa and then veers into eastern Iowa between 06 to 12 UTC and then along and east of the river after 12 UTC. CAMS and synoptic models show limited amounts of CAPE resulting in diminishing thunderstorms and showers. These continue through the morning before dissipating during the afternoon. Another, stronger disturbance will move across the area on Friday evening and night with some instability building across the area in the wake of a warm front that lifts into Wisconsin. Models show CAPE of 1000 to 1500 J/KG and 0 to 6 km shear of 30 to 40 knots. This is sufficient for severe thunderstorms to developing during the evening. Think that hail and damaging wind gusts will be the primary threat. Models also show 2.00 to 2.25 inches of precipitable water so heavy rain is also a threat. The Storm Prediction Center has a Slight or level 2 out of 5 Risk for severe storms along west of a line from Cedar Rapids to to Kahoka Missouri with a Marginal or level 1 out of 5 risk of severe storms to the east. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Issued at 202 PM CDT Thu Jun 27 2024 A progressive zonal flow is forecast to remain in place across the region through the long term. A storm system moving through the flow will bring chances of precipitation Monday through Thursday. Ridging will build northward in the wake of this storm system early next week and allow warm temperatures so surge northward for the middle of next week. Showers and storms will linger across far southeast Iowa, west central Illinois and northeast Missouri as cool front sinks across the remainder of the area during the morning hours on Saturday. High temperatures on Saturday in the 80s. High pressure is forecast slowly build into the region Saturday into Sunday at the surface and aloft. The weather will be pleasant with slowly falling dewpoints into Sunday. Low temperatures on Sunday morning will range from the upper 50s to lower 60s. High temperatures on Sunday will be below normal and in the 70s. Another storm system will approach the area later in the day on Monday and bring increasing chances of showers and storms through Wednesday. Current model runs show better instability and precipitable water values of 2.00 to 2.25 building into the area. Heavy rain will be the main threat. It is to early to determine the severe potential. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 705 PM CDT Thu Jun 27 2024 Scattered showers are possible tonight, especially near CID and DBQ. The lower atmosphere will take time to saturate with VFR ceilings likely to prevail through the overnight period. Then heading into Friday, coverage of showers and isolated storms will increase which may lead to periods of MVFR (mainly at CID and DBQ). The active weather will continue through the end of this TAF cycle with chances for scattered showers and storms into Friday night. Will hold off on mentioning thunder in the TAFs for now due to low confidence. && .HYDROLOGY... Issued at 202 PM CDT Thu Jun 27 2024 Change: The Mississippi River at Rock Island: A flood warning for MAJOR flood category is in effect until further notice. The river is expected to continue to rise to 18.0 ft on July 4th. However, additional rises thereafter are likely. Rainfall potential: Several storm systems may bring heavy rainfall to the Midwest, which may aggravate the flooding or delay any crests. There is additional showers and thunderstorms this Friday and Friday night, again early next week, and another system towards the end of next week. Stay tuned! Outlook... The overall weather pattern looks to remain quite active through Independence Day and potentially into the middle of July. The Madden- Julian Oscillation (MJO) which has been weak to non-existent for much of June is forecast to strengthen over the next 10 days and is forecast to move from phase 2 to phase 4 over the next two weeks. Phase 3 and 4 of the MJO climatologically correlates to above normal rainfall for the upper Midwest and Mid-Mississippi Valley. Indeed the Climate Prediction Center has a 40-50 percent probability of above normal rainfall July 4-10. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...None. IL...None. MO...None. && $$ SHORT TERM...Cousins LONG TERM...Cousins AVIATION...Uttech HYDROLOGY...Haase