942 
FXUS63 KMPX 121155
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
555 AM CST Sat Jan 12 2019

.UPDATE...
Issued at 542 AM CST Sat Jan 12 2019

Updated to include 12z aviation discussion below.

&&

.SHORT TERM...(Today through Sunday)
Issued at 230 AM CST Sat Jan 12 2019

Surface analysis early this morning depicts a weak north-south 
oriented surface trough over central MN, associated with a 
dissipating northern-stream low pressure center over western IA. 
The larger more potent southern stream low pressure center 
continues to slowly shift east over southern OK. High pressure 
over south-central Canada spreads southeast across the Great Lakes
into the Mid-Atlantic and New England regions. Aloft, a potent 
cutoff low over southern KS continues to drive the motion of the 
southern-stream low while a sharp ridge stays stoic just of the 
west of the Rockies. 

Over the next 12-24 hours, the ridge will expand eastward over 
the northern Rockies through to the Great Lakes while a weak 
trough in advance of the ridge slides south over southern MN/WI. 
Sufficient mid level moisture with the trough will maintain cloud 
cover over the area for much of the day. However, lesser low level
moisture plus weak forcing will mitigate precipitation production
(zero QPF) so have opted to run with a dry forecast. The ridge 
filling in to the north along with approaching high pressure will 
help suppress the southern-stream low pressure system to the 
south, far enough such that no precipitation from that system will
reach into MN/WI. That system will then shift east into the 
Tennessee River Valley while high pressure expands over the Upper 
Mississippi River Valley tonight through Sunday. More breaks in 
the clouds are expected for Sunday, mainly for far southern MN and
southwestern WI.

Temperatures both today and Sunday will run rather similar, due to
the lack of airmass change even with the passage of the weak
trough and incoming high pressure. Highs both today and tomorrow
will run in the mid 20s to lower 30s. Lows early this morning and
early Sunday morning will range from the mid teens to lower 20s.

.LONG TERM...(Sunday night through Friday)
Issued at 230 AM CST Sat Jan 12 2019

Overall pattern shift looms in the longer term resulting is a
shift from mild/dry conditions to much colder regime by late in
the week. 

We see a relatively calm period early with the main jet energy 
riding well north of the CWA. This does gradually shifts south 
with time as the significant southern stream storm exits off the 
east coast. This allows a couple of cold fronts to drop south 
into the area. The first arrives Tuesday afternoon. We should see
mild temepratures, possible warming through the upper 30s the
first part of the week. The front appears to move through the 
area dry Tuesday evening with the better forcing/deeper moisture 
shunted to the northeast. 

The deterministic models diverge greatly by the end of the week,
by how deeply the area will remain in the cold air with the
passage of the secondary cold front on Thursday. This front will
bring at least a chance of snow to the region Thursday perhaps 
into the day Friday. The ECMWF has trended much colder with the 
area becoming entrenched in the colder air by Friday and 
lingering through next weekend. The GFS brings the cold front 
through Thursday but holds out for one last system to move through
next Monday before the arctic surge takes place. Still, the trend
toward much colder looks good through the end of next week, with 
perhaps some light snow with cold frontal passage. 

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 502 AM CST Sat Jan 12 2019

Ceilings will prevail throughout this TAF set, it's a matter of
whether they're VFR or MVFR. MVFR ceilings occupy much of north-
central thru western MN and it's expected that's where they'll
stay (thus impacting KAXN-KRWF primarily). Remaining TAF sites are
expected to have ceilings settle in the 040-050 height later this
morning through tonight. No precipitation expected at any of the
TAF sites. Winds will run generally NE in the 5-10 kt range.

KMSP...Not expecting ceilings to drop to MVFR range but it cannot
be completely ruled out. Will look for ceilings around 050 to
develop later this morning and remain there tonight through Sunday
morning.

/OUTLOOK FOR KMSP/
Sun...Mainly VFR. Chc MVFR ceilings. Wind SE 5 kts becoming SW. 
Mon...Mainly VFR. Chc MVFR ceilings. Wind SW 5 kts. 
Tue...VFR. Wind SW 5-10 kts becoming NW.

&&

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

$$

UPDATE...JPC
SHORT TERM...JPC
LONG TERM...DWE
AVIATION...JPC