THE CHILL IS ON...
Scattered frost is on the pumpkins around many parts of the Midwest thanks to a sprawling high pressure situated over the region. That's provided clear skies, light winds, and dry air. Combine that with nights that have been getting shorter by the day for over 3 months and you can readily see the chilling effect it produces. Early Wednesday frost advisories or freeze warnings cover parts of 7 states.
Here's the high pressure delivering the cold situated just east of Minneapolis Wednesday morning.
You can also see the very dry air that's located near and east of the high pressure center.
Expanding the view, it's also easy to pick out the tropical moisture over the southeastern U.S. associated with hurricane Ian which is barreling towards west Florida.
I came upon and interesting graphic from the Iowa Mesonet which I thought was compelling. It shows temperature departures associated with landfalling east coast hurricanes with those landfalling on the Gulf of Mexico. Using 185 events as the data base, readings were shown to be below normal preceding hurricanes that travel across the east coast. When storms landfall further west in the Gulf, readings are above normal.
The results make sense as the Midwest would be within a 500mb trough with NW flow during east coast hurricanes. That certainly is the case with Ian. You can clearly see the storm approaching Florida and the digging trough that guides the hurricanes movement. The resultant NW flow brings us our chilly temperatures.
If Ian was landfalling in Texas or Louisiana a ridge would be over the east directing it there. It would also bring a warmer more humid brand of weather to the Midwest. Pretty interesting if you ask me.
Speaking of the hurricane, it's looking more and more likely that landfall will occur between Tampa and Ft. Myers. The worst winds and storm surge are anticipated with that area. The EURO shows the center near Venice around 1:00pm Wednesday when it makes landfall. Wobbles are still possible so any place from Tampa to Ft. Myers needs to be on high alert. Ian is projected to be an extremely dangerous major hurricane when it makes landfall later Wednesday.
One of the primary reasons is of course high winds. At 10 meters the EURO has a gust of 121 near Venice.
The other major concern is an 8-12 foot storm surge and very heavy rain. Within the heavy rain band in purple, the GFS has a rain maximum of 23.93" just east of Tampa. Significant flooding from the storm surge and heavy rain is expected.
The highest surge of 8-12 feet is shown just south of Tampa to near Ft. Myers. Remember, high waves on top if the surge make it even more dangerous and potentially devastating.
For those interested, you can get the latest updates on Ian by way of this link tied to the National Hurricane Center. https://www.nhc.noaa.gov/graphics_at4.shtml?start#contents
With Ian's slow movement over the southeast the next 48 hours, our weather in the Midwest is not likely to change significantly the next 48 hours as high temperatures hold in the upper 50s Wednesday and the low 60s Thursday. Lows remain crisp in the range of 35 to 40. Sunny skies are expected.
By Friday the east coast trough inches east allowing a slow warming trend. Temperatures should reach the mid 60s Friday and should settle in around 70 both Saturday and Sunday. Lows climb back into the range of 40-45. Overall conditions remain dry and mostly sunny. It looks like a beautiful weekend and a terrific start to October.
The dry, storm free pattern should continue much of the next 10 days. The GFS show essentially no rain over the central Midwest during the 10 day period ending October 8th.
That's all I have for you today. Enjoy the crisp fall conditions and as always, roll weather...TS
