Area Forecast Discussion

FXUS63 KMQT 201956

Area Forecast Discussion
National Weather Service Marquette MI
356 PM EDT Sun May 20 2018

.SHORT TERM...(This evening through Monday)
Issued at 346 PM EDT SUN MAY 20 2018

Water vapor imagery and RAP analysis show a split flow pattern over 
the western CONUS with a wnw confluent flow aloft into the Upper 
Great Lakes region and sfc high pressure dominating. Lake breezes 
have kept conditions cooler this afternoon near the Great Lakes 
shores (40s and lower 50s) while much farther inland under sunny 
skies and deeper mixing temps have risen in the upper 60s/lower 70s 
along the WI border.  

Winds will diminish to calm/near calm tonight, setting the stage for 
a chilly night as dry air mass (precipitable water as low as one-
quarter to one-third inch) aids radiational cooling potential. Will 
continue to favored the lowest of available guidance, bias corrected 
mos guidance and bias corrected CMC global which is normally a 
superior performer on radiational cooling nights. Traditional 
interior cold spots should fall into the upper 20s/around 30F.

Sfc high pressure will remain in control continuing the dry 
conditions on Monday. With the center of the high moving east 
southeast gradient winds will increase near 10 mph with gusts 
reaching over 15 mph at times over the west half of the fcst area. 
The winds combined with high temps reaching into the lower 70s and 
minimum RHs lowering into the 20 to 25 percent range will contribute 
to elevated fire weather concerns especially over the west half. 
Shortwave lifting ne from the Central Plains could bring some mid- 
high clouds into s central portions in the afternoon, although any 
showers associated with this system should remain south on Monday.

.LONG TERM...(Monday night through Sunday)
Issued at 356 PM EDT SUN MAY 20 2018

The main weather concern through the middle of the week will be 
elevated wildfire potential, especially inland from the Great Lakes 
where dewpoints in the afternoon hours will drop into the 20s. A 
thermal trough is expected to develop across the interior during the 
afternoon hours as temperatures heat up into the 70s and lower 80s 
across the interior and lake breezes dominate the low-level wind 
fields. The development of this thermal trough inland of the Great 
Lakes will be reinforced on Wednesday as a weakening, dry backdoor 
cold front drops south. Compressional along this trough axis should 
allow for another day with well-above normal temperatures on 

Thursday through early parts of the Memorial Day Weekend will 
become much more active weather wise with increasing chances for 
showers and thunderstorms. As result temperatures will be a bit more 
difficult to forecast based on how cloud cover and precipitation 
evolve. With the main shortwave associated with this pattern change 
lifting northeast from the southwest into the northern Plains, this 
track will favor good moisture transport this far north as the Gulf 
of Mexico is progged to be open for days in advance. As this axis of 
low to mid-level moisture gets into Upper Michigan on Thursday, we 
will start to see chance for showers and storms increase across the 
west half of Upper Michigan. With this convection well removed from 
the main upper-level forcing, thinking the primary area of concern 
will be along lake breeze boundaries and the far eastern edge of the 
warm front, associated with a developing surface low in the northern 
Plains. On Friday and Saturday, the surface low will track towards 
the Arrowhead of Minnesota and then drop south across Wisconsin. 
This should allow the warm front to gradually lift north across 
Upper Michigan and allow for better chances for showers and 
thunderstorms on Friday in the vicinity of the frontal boundary, as 
well as lake breeze boundaries. On Saturday, as the low pressure 
system tracks just to our south, this will allow for additional 
chances for showers and thunderstorms. Towards the tail end of the 
weekend, as the surface low continues to track south of the area we 
should see a cool down, but lingering showers are not out of the 
question. Right now it is difficult to say whether or not we will 
see any strong to severe storms during this time period. However, 
with a weakening, yet still impressive elevated mixed layer progged 
to track across the region on Friday, this would favor a better 
environment for stronger updrafts. Based on the current instability 
axis and deep-layer shear profiles it appears that at least pesky 
pulse-type thunderstorms won't be out of the question. Overall, if 
you have outdoor activities planned towards the end of the work week 
and the Memorial Day Weekend you'll definitely want to keep an eye 
on the weather. Even if we don't see stronger storms, remember 
lightning is always a hazard with thunderstorms.

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 122 PM EDT SUN MAY 20 2018

With high pres and a very dry air mass dominating, VFR conditions 
will prevail at KIWD/KCMX/KSAW thru this fcst period.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 346 PM EDT SUN MAY 20 2018

Sfc high pres ridge over the Upper Lakes has led to winds under 15kt 
today across most of Lake Superior this afternoon. However, with the 
ridge axis setting up across southern Lake Superior, sw winds over 
the n central part of the lake could gust as high as 20kt late this 
afternoon. High pres will then remain over the Great Lakes region 
into Tue, resulting in winds mostly under 15kt. Although a cold 
front will drop s across Lake Superior Tue night/Wed morning, it 
will be weak, and winds will likely remain mostly under 15kt thru 
Wed and into Thu.

Upper Michigan...
Lake Superior...
Lake Michigan...


LONG TERM...Ritzman