Area Forecast Discussion
Issued by NWS Quad Cities, IA IL
Issued by NWS Quad Cities, IA IL
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315 FXUS63 KDVN 142332 AFDDVN Area Forecast Discussion National Weather Service Quad Cities IA IL 632 PM CDT Sat Sep 14 2024 .KEY MESSAGES... - Continued above normal temperatures with with potential for above normal temperatures into the first third of October. - The best chances for any measurable rain look to be next weekend when a cold front moves through the Midwest. The timing of that front may depend upon when and if Helene forms. - There is a signal suggesting the potential for below normal precipitation into the first third of October. && .SHORT TERM /THROUGH TONIGHT/... Issued at 225 PM CDT Sat Sep 14 2024 Isolated showers/sprinkles or even a thunderstorm may develop during peak heating this afternoon that will dissipate with sunset. Satellite does show developing cumulus mainly south of I-80 and concentrated around the Mississippi River. Trends with the HRRR/RAP have been pointing to this area for possible diurnal convection late this afternoon. Areal coverage of any convection that develops this afternoon would be around 10 percent so a majority of the area will remain dry but somewhat humid. Sprinkles or isolated showers may develop late tonight west of the Mississippi in an area of weak convergence over the western third of the area. Again, coverage on any precipitation would be 10 percent at best. On Sunday another warm and somewhat humid day will be in store for the area. Some sprinkles or isolated showers may or may not occur west of the Mississippi during the morning. Another round of sprinkles or isolated showers are expected to develop during peak heating for areas mainly west of the Mississippi in the afternoon. A rogue thunderstorm cannot be ruled out. && .LONG TERM /SUNDAY THROUGH SATURDAY/... Issued at 225 PM CDT Sat Sep 14 2024 Sunday night through Thursday Assessment...medium to high confidence on continued dry conditions. High confidence on above normal temperatures. The model consensus has dry conditions across the area as a strong surface high remains over New England and southern Canada with an upper level high in the eastern Great Lakes. If Helene does develop off the southeast coast, that would result in a rex block over the eastern CONUS and slow or stall systems ejecting from the trof over the western CONUS. The net result is temperatures well above normal with little if any rain. Thursday night through Friday night Assessment...low to medium confidence on rain chances. High confidence on above normal temperatures. The overall trend of the model consensus has been to slowly back off on the rain chances Thursday night through Friday night. As mentioned earlier if Helene does develop by early next week it would help develop a blocking pattern and slow down or stall any systems coming out of the trof over the western CONUS. Given the NHC probability of Helene developing is now at 40% (next 48 hours) and 50% (next 7 days) it would be reasonable to expect the rain chances for Thursday night through Friday night will continue to slowly decrease as next week progresses. Saturday Assessment...medium confidence on rain occurring. High confidence on above normal temperatures. The model consensus has 20 to 30 percent chances for rain with the higher chances west of the Mississippi. Again, the trend of the model consensus has been to slowly lower the rain chances. The deterministic runs of the CMC/ECMWF keep the area dry through Saturday night while the GFS has some rain west of the Mississippi. The CMCE/EPS/GEFS have several members that are more robust with rainfall and thus are contributing to the increased but trending down of pops for Saturday. && .AVIATION /00Z TAFS THROUGH 00Z MONDAY/... Issued at 628 PM CDT Sat Sep 14 2024 Isolated showers and storms are possible near BRL and MLI through 02Z/Sunday before the activity quickly dissipates. Confidence is low on thunder at the TAF sites; we will be monitoring closely and may need to update with TEMPOs. Brief MVFR and gusty winds are possible in the vicinity of any showers/storms. For the remainder of tonight, expect prevailing VFR and light winds. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...None. IL...None. MO...None. && $$ SHORT TERM...08 LONG TERM...08 AVIATION...Uttech