SUMMER IN THE CITY....
Our weekend got off to a sizzling start Friday. For a change there were no convective boundaries or forcing in place to set off storms during the day. As a result with a highly capped atmosphere sunny skies and very steamy conditions prevailed throughout the area. Highs in most spots were in the range of 90-92 with heat index values as high as 102.
While there was limited rain in my area Friday, that was not the case just to the north were much of northern Iowa and southern Minnesota racked up 2-5" totals through early morning. This put a capper on a very active week that saw rain in every part of my region. That said, all areas were not drenched accordingly with spots just NE of the Quad Cities and further south around Burlington seeing 1/2" or less. Many other locations, especially the drought riddled regions of Iowa to my NW picked up welcome 2-4 rains, in some areas more than had fallen all summer. Thanks to new storms Friday evening, more heavy rain developed and Doppler estimates are now indicating36 hour totals near 10 inches in NE Iowa near the Minnesota border. The amounts you see below are only through 7:00 AM Friday.
I came across this graphic on the Iowa Mesonet which depicts the number of days from now that one must go back in time to accumulate at least three inches of precipitation. The yellowish blotches in parts of SE Iowa show it's been between 40 and 60 days since rain has totaled three inches. Hopefully future rounds of storms will help to fill the gaps in. I did want to point out though the growing amounts of blue where three or more inches was measured in just the past 1-10 days. Progress for sure!
One thing that's happened over the past 24 hours is a northward shift in the ring of fire. That has moved the spawning grounds for thunderstorm clusters to the north and I see little change in that pattern Saturday. Outside of a slight chance of storms early in the far north, (particularly north of HWY 20) I look for another dry sticky day with ample sunshine. Highs should again break into the upper 80s far north to the low 90s elsewhere. Some local spots where soil conditions are driest may even pop a few highs of 93-95. The GFS does see that potential and shows the effect in its projected highs Saturday afternoon.
Some models do indicate dew points a bit lower than Friday and as such heat index levels Saturday should fall just short of advisory levels in the range of 95-101. A few places may out perform that range though and a heat advisory has been issued by the NWS for some of my southern counties near and south of HWY 34. That could be expanded north if conditions warrant early Saturday.
Sunday brings the threat of some additional storms with the passage of a late afternoon or early evening cool front. Models are less excited about prospects than 24 hours ago primarily due to a faster frontal passage. While a few storms are possible the best chances appear to be SE of the Quad Cities, especially in Illinois. It should be another warm sticky day before cooler and drier air gets established Sunday night and Monday. Here's what models are indicating for rainfall Saturday through Sunday night.
The 3k NAM
The 12K NAM
The WPC blend
We will get a break from the warm muggy conditions early next week but the active pattern is likely to return for the middle and later parts. Whether or not that means much rain will be determined by where synoptic features are established. Plenty of time to figure that out.
The big weather story nationally is going to be hurricane Ida. Models continue to dial in on a landfall in SE Louisiana towards Sunday evening. The spaghetti plots look like this.
Hurricane Warnings are already in effect for much of coastal Louisiana including cities such as New Orleans, Baton Rouge, and Lafayette.
This statement was issued by the National Hurricane Center regarding Ida's development. As it stands now, NHC believes it will be an extremely dangerous category 4 storm with potentially catastrophic wind damage near where the core moves ashore.
Models show a very favorable upper-level wind pattern over the storm and abundant environmental moisture. These conducive atmospheric conditions combined with very warm Gulf of Mexico waters should allow Ida to rapidly intensify this weekend. In fact, it seems likely that Ida will pass over a warm eddy over the central Gulf of Mexico, where the ocean heat content is very high. All of the models show significant strengthening, but there is a fair amount of spread on how strong the hurricane will get. The NHC intensity forecast remains near the high end of the model guidance, and shows Ida becoming an extremely dangerous category 4 hurricane prior to reaching the coast. After landfall, rapid weakening is expected due to land interaction, drier air, and an increase in shear. Ida is expected to be an extremely dangerous major hurricane when it reaches the coast of Louisiana. Hurricane-force winds are expected Sunday in portions of the Hurricane Warning area along the Louisiana coast, including metropolitan New Orleans, with potentially catastrophic wind damage possible where the core of Ida moves onshore. Actions to protect life and property should be rushed to completion in the warning area.
Model intensity guidance looks like this. NHC is taking the high end scenario.