Fresh Front: Less humid, NWS upgrades Doppler
I hope you passed the first AC test this season. You may now give your AC unit a rest for a couple for days.
A fresh north breeze is pumping in a more comfortable less humid air mass. We'll all be breathing a little easier Wednesday. The source region for this delicious early summer air mass? The still icy waters of Lake Superior. 'Cooler by the Lake' is the watchword in spring along the North Shore. A northeast breeze funnels a "modified" Lake Superior air mass over Minnesota the next 48 hours.
July like temps
It's still plenty warm away from the big Lake this week. Temps in the mid-80s are more typical for July, not the last week in May. Welcome to Minnesota, where average is just a loose weather concept.
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Summery pattern
The weather maps look typical for summer. A pleasantly warm and dry high pressure ridge (did I just type that for the first time in 9 months?) stalls overhead this week, then a front brings scattered storms this weekend.
NWS Doppler upgrade doubles frequency of scans
Friday the Twin Cities NWS installed the new "Build 14" Doppler upgrade. This one is a big step forward of severe weather coverage. We'll now get low level base scans of storms about twice as often, going to every 2 minutes 20 seconds from 5 or 6 minutes previously.
This can be a big help during rapidly developing severe storms, and could literally give us a couple extra minutes more lead time on developing tornadoes.
It will also eliminate the "sunset spikes" observed as the Doppler picks up rays from the setting sun.
Here's the scoop from the Twin Cities NWS.
Radar Build 14 Installed at KMPX
Build 14 was installed on the Chanhassen WSR-88d on Friday, May 23rd. This latest build offers SAILS, an acronym for Supplemental Adaptive Intra-Volume Low-Level Scan. This is a significant new option, only available with our severe weather Volume Coverage Patterns (VCP's). It adds a new low level 0.5 deg scan in the middle of the VCP (time-wise). Hence, in severe weather we can now receive a new low level scan every 2 min 20 seconds. Another feature with this build is the Radial by Radial Noise Estimation. One of the aspects of this feature is the removal or greatly reduced sunrise and sunset spikes observed daily from the WSR-88's across the country. Attached is an image from our radar Saturday evening showing where the sunset spike would have been. Radars in Duluth and Sioux Falls exhibit the sunset spike as their radars have not been upgraded to the new build yet. Most, if not all NWS radars will be upgraded to Build 14 by the end of June.
