Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 110012
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
612 PM CST Mon Dec 10 2018

.SHORT TERM...(This evening through Tuesday)
Issued at 254 PM CST Mon Dec 10 2018

Stratus continues to clear from west to east and the clearing line
has now reached I-35. It should continue eastward into the
evening hours. Just some thin high clouds are moving into western
MN from the Dakotas late this afternoon, but they are expected to
thicken some later tonight. This could hamper robust fog formation,
but there are still decent probs (35-60%) on the SREF and HREF
for low stratus and visibilities around 1 mile redeveloping area
wide after midnight. Increased cloud cover from the previous
forecast after this evening and continued the mention of fog
through Tuesday morning.

.LONG TERM...(Tuesday night through Monday)
Issued at 254 PM CST Mon Dec 10 2018

The long term period features multiple shortwave troughs passing
over the area, as a strong jet comes onshore off the Pacific
coast. The first of these approaches the area late Tuesday night
into Wednesday with strong vorticity advection resulting in a
cutoff low forming east of the area over the Great Lakes. Given
the better forcing holding off until the wave is east of the area,
not expecting much in the way of precipitation out of this
system. Forecasts soundings continue to show little ice in the
column, so light freezing drizzle continues to look possible along
with periods of flurries when/if ice can get introduced to the
cloud layer. With temperatures in the low-mid 20s Wednesday
morning there could be some slick areas on untreated roads during
the morning commute, primarily across southern Minnesota and west-
central Wisconsin.

Right on this system`s heels comes another, more organized, trough
Thursday as the northern and southern jets interact over the
Mississippi Valley. However, the best forcing with this trough
remains tied to the southern jet over the lower-Mississippi valley
so expecting little in the way of precip over our area again as
moisture remains scant across the upper Midwest. Forecast soundings
continue to show a mid-level dry layer around 700 mb, but think
enough ice will be introduced by a seeder cloud layer above to
result in light snow/flurries. Only a dusting of accumulation is
expected.

Beyond Thursday, benign and milder weather looks to prevail as the
jet remains well north of the area. Broad ridging builds over the
central US over the weekend which will keep temperatures mild into
the middle of next week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 612 PM CST Mon Dec 10 2018

It`s yet another night with a shallow near surface moisture layer
trapped beneath a strong and very dry inversion. The last couple
of nights, the HRRR has done a good job at capturing the main idea
for the evolution of the stratus and fog, so stayed close to it`s
idea tonight for these TAFs. Expect the stratus over WI now to
clear RNH/EAU shortly, but will stall out over central WI and
start to creep back west. It is looking likely that EAU will have
another FZFG/stratus event Tue morning, with RNH possibly having
issues as well. It is looking like MN terminals will have
nothing worse than an MVFR vis. Cirrus streaming in from the
Dakotas should help in keeping stratus/fog from becoming
problematic in MN. For Tuesday, mid/upper clouds will thicken as a
trough works across the Dakotas, but no precip or MVFR conditions
are expected during this period.

KMSP...Looking at forecast soundings, moisture is forecast to be
more shallow Tuesday morning than it was Monday morning, so agree
with the HRRRs idea that it`s likely going to be a VFR night.
Still, we have some reduced vis at 00z at FCM and LVN, so can`t
rule out some vis restrictions through the night as the temps
cool to near the dewpoint, so maintained MVFR vis mention from
previous TAFs. Clouds will thicken and lower through the afternoon
Tuesday, but not expecting any sub VFR cigs or any sort of precip
chance until after this TAF period.

/OUTLOOK FOR KMSP/
Wed...MVFR/IFR ceilings. Wind SE 5 kts.
Thu...MVFR ceilings. Wind lgt and vrb.
Fri...VFR. Winds W 5 kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&

$$

SHORT TERM...BORGHOFF
LONG TERM...ETA
AVIATION...MPG



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