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fxus63 kmpx 181127 

Area forecast discussion
National Weather Service Twin Cities/Chanhassen Minnesota
627 am CDT Fri Oct 18 2019

issued at 621 am CDT Fri Oct 18 2019

Updated to include 12z aviation discussion below.


Short term...(today through saturday)
issued at 429 am CDT Fri Oct 18 2019

Surface analysis early this morning shows a large north-south
oriented area of high pressure from Hudson Bay into the lower
Mississippi River valley and a cold front extending south from
central Saskatchewan province through ND then bending southwest
over northwestern South Dakota through eastern Colorado. Aloft, a Sharp Ridge axis
sits over the central Continental U.S. While deep longwave troughs reside
over east Continental U.S. Coast.

The ridge aloft will shift to the east today, making for deep
pronounced warm air advection across the region today through
tonight in advance of the approaching cold front. With h925 temps
hitting the 12c-15c range over southern portions of the weather forecast office mpx
coverage area, highs will easily climb into the upper 60s with a
few 70-degree readings not unreasonable. However, the other pre-
frontal impact will be a tight pressure gradient between the large
high pressure area to the east and several low pressure centers
along the front. This will make for strong southerly winds,
especially in southern and southeastern Minnesota. Sustained speeds will
reach 20-30mph with gusts of 40-50mph late this morning through
this afternoon. With these strong winds in a nearly perpendicular
fashion over such highly traveled freeways such as I-90, US 14 and
state rte 30 in southern Minnesota, there is some concerns for hazardous
travel for high profile vehicles. As such, after collaboration
with surrounding offices, a Wind Advisory has been issued for
portions of southern Minnesota today.

While winds speeds diminish after dark this evening, the closer
proximity of the front along with a narrow swath of moisture may
be able to produce isolated to scattered rain showers mainly along
and east of the I-35 corridor late tonight through the day
tomorrow. Not looking for much in the way of intensity or
coverage, and quantitative precipitation forecast backs that up with less than a tenth of an inch
of rain expected for areas that do receive rainfall.

The cold front will push across Minnesota tonight, reaching the Minnesota/WI
border by daybreak Saturday, then continue to push east during the
day tomorrow, reaching Lake Michigan by sunset. As such, any
rainfall for the weather forecast office mpx coverage area should be to the east of
the area by mid-to-late afternoon. The upper level pattern will
not be all that conducive for appreciable cold air advection
starting tomorrow (more so Sunday and onward). As such, Max
temperatures on Saturday will only be a few degrees cooler than
those expected today. Will look for highs in the upper 50s to mid
60s Saturday.

Long term...(saturday night through thursday)
issued at 429 am CDT Fri Oct 18 2019

The long term period starts off active with a trough digging
across the upper Midwest Sunday-Tuesday, and a Colorado low
deepening over the Southern Plains and tracking northeast through
the County Warning Area. Rain will spread east across the area Sunday
afternoon/evening as a broad precipitation shield develops out
ahead of the surface low. Can't rule out some thunder with this
initial precipitation, but only marginal values of MUCAPE should
keep it fairly isolated. Rain continues into Monday morning, but
we'll likely see a dry period during the day as the low passes
overhead and places the area in the dry slot of the cyclone. Winds
will become quite gusty Monday as the low bottoms over southern
Minnesota and low-level lapse rates steepen behind a cold front.
Wind gusts of 40-50 mph look possible Monday afternoon across
western and southwest Minnesota. Another round of precipitation is
expected late Monday though Tuesday morning as the wrap-around
region of the low passes overhead, with temperatures possibly
cooling enough by Tuesday morning for some light snow to mix in
across western and west-central Minnesota.

We should briefly dry out Tuesday afternoon into Wednesday as the
flow becomes briefly zonal aloft, but another trough digs into the
central US by Thursday. Guidance still differs in the timing and
strength of this trough, but it looks like a weak surface low will
develop and track somewhere across southern Minnesota or northern
Iowa. A swath of light rain looks possible to the north of this
low Wednesday night/Thursday, with maybe even some light snow
mixing in across central Minnesota. While the timing of this
precip is still uncertain, confidence is high that temperatures
will fall back to well-below normal values Thursday/Friday.


Aviation...(for the 12z tafs through 12z Saturday morning)
issued at 621 am CDT Fri Oct 18 2019

VFR conditions at all sites through this evening as high pressure
departs to the east. Strong southerly winds will develop by late
morning, with sustained winds in the 15-25kt range and gusts
upwards of 35kt at times. Winds will subside a bit this evening.
However, low level wind shear will still be an issue, especially around
initialization time and again late this evening into the early
morning hours. During the early morning hours Saturday through
daybreak, as a cold front slowly pushes across the area, a few
showers are possible mainly along and east of I-35. Best chances
for -shra will be far inland western WI, along with the best
potential for any MVFR ceilings.

Kmsp...VFR the entire taf set. There looks to be two distinct
periods of llws, one currently through late morning then another
late this evening into the early morning hours.

/Outlook for kmsp/
Sat...VFR. Rain showers possible late. Wind west 5-10 kts.
Sun...VFR with MVFR/IFR/-shra late. Winds southeast at 15g25 kts
Mon...IFR/-shra early, then MVFR. Wind northwest at 20g30 kts.


Mpx watches/warnings/advisories...
Minnesota...Wind Advisory from 10 am this morning to 6 PM CDT this evening
for mnz083>085-091>093.



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