FROM THE SUBLIME TO THE SLIME...
Holy Mackerel, was Wednesday a fantastic day or what? I mean really, it doesn't get any better than that as evidenced by the fact the Quad Cities set a new daily high temperature record with a high of 78. The old mark was 77 set in 1999. Cedar Rapids and Burlington both reached 76 which ties the existing records again set in 1999. Dubuque with a 73 was a degree short of the standing mark of 74 set in 1999. Ft Madison and Washington were the days warm spots at 79! The grills were fired up on my street and the evening air was laden with the scent of barbecue!
We're about to change seasons now and we'll do it lickity split thanks to a powerful cold front. Before the flip, most of Thursday will be spent in the warm sector out ahead of the front. Starting the day with readings already in the 60s, it won't take much to send highs back into the 70s. If clouds and precipitation hold off long enough, record highs could once again be threatened. Here's a look at what we are targeting.
RECORD HIGHS FOR THURSDAY NOVEMBER 10th
Cedar Rapids...........72, 2012
At noon, the hi-res HRRR indicates temperatures in the 70s, near or already above the days records.
About the time temperatures are at their peak in the afternoon, the cold front arrives from the west and it will be the catalyst for showers and thunderstorms. Surface CAPE will be on the lower end but it will be augmented by low level shear. The low CAPE, high shear environment will provide a 2-3 hour window for stronger storms with some wind and perhaps an isolated brief weak tornado spin up. The potential is short and confined to initial storm development when more isolated cells can tap into whatever CAPE is constructed through the days heating. After sunset, parameters weaken and showers and storms become more anafrontal as they streak east along with the cold front. SPC does have much of my counties in Iowa highlighted in a marginal risk but that has been downgraded from the slight convective assessment issued 24 hours earlier.
At 6:00 in the evening you can see the line of showers and thunderstorms delineating the cold front as it approaches the Mississippi.
OPENING THE DOOR TO WINTER...
With the passage of the cold front precipitation shuts down pretty quickly only to redevelop behind the front. Scattered showers could continue into the wee hours of the morning and may even mix with some snow before ending.
By now we have opened the door to winter temperatures. At 6:00pm Thursday evening readings have dropped 15-20 degrees in just 3 hours time behind the front.
At 8:00am Friday morning the HRRR has temperatures in the upper 20 to low 30s. A solid 40-45 degrees cooler than 18 hours earlier.
Wind chills NW of the river at that time are in the mid to upper teens. If you incorporate the "feel-like" aspect into the equation, it is likely to feel 55-60 degrees colder than just 18 hours earlier. Rest assured, this is going to get your attention!
After some morning sunshine Friday, clouds will spin in from the north and remain intact through Saturday. The steep lapse rates and some weak vorticity may generate a few snow showers or flurries, especially across the north. Some lucky spots might see a dusting.
As for weekend temperatures, they are going nowhere and I look for highs to remain in the low to mid 30s Friday through Sunday. Lows should remain in the mid to upper 20s due to the influence of clouds. However, if we can break out for an hour or two it could be considerably colder, especially Sunday morning.
Things get more interesting Monday night and Tuesday as energy from a southern branch disturbance and one in the northern branch traverse the central U.S. They never really phase but develop an inverted trough that sends enough moisture and lift into the region to develop some light snow or snow showers. The EURO even has some totals in the 2-3 inch+ range.
The GFS has come around to the EURO idea in my northern counties but not so much in the south.
Personally, I think with such an energetic pattern it's just too early to jump on any band wagon. We've got some time to get trends figured out but as I mentioned in yesterday's post, I think there is a pretty good chance many of us see the seasons first measurable snow out of this set-up next week. Stay tuned!
Once we get into the cold it appears to in place for a good 8-10 days before moderation arrives. Here's the 10 day average temperature departures for the period November 11-21st. Quite fresh.
Okay then, get out and feel that balmy air. Put it in a jar and save it as I doubt we get this warm again for several months to come. Roll weather...TS