Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 260915
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
415 AM CDT Thu Apr 26 2018

.SHORT TERM...(Today and tonight)
Issued at 415 AM CDT Thu Apr 26 2018

A cold front continued to surge southward across northwest Minnesota
early this morning. As of 330 am, this front was located near Fergus
Falls, Minnesota. Behind this front, winds were gusting above 25
mph. Although a few sprinkles may occur along this front, deep
moisture is limited and no measurable precipitation is expected
today. Morning cloud cover will quickly dissipate by the afternoon
with plenty of sunshine later this afternoon. The main weather
concern this afternoon is fire weather conditions as winds increase,
and dew points drop into the 20s in west central and central
Minnesota. Dew points are slightly higher along the front but still
in the 30s. The lower dew points will translate into low humidity
levels this afternoon. These lower humidity levels, combined with
the strong northwest winds of 20 to 30 mph, will create an elevated
risk of rapidly spreading fires, if fires develop. Winds should
begin to diminish around 6-7 pm. However, another front moving
across the area on Friday will likely increase southwesterly winds
ahead of it toward sunrise Friday.

.LONG TERM...(Friday through Wednesday)
Issued at 415 AM CDT Thu Apr 26 2018

The cold front will be passing through Friday morning. Highs will
likely be reached early, before falling some in the afternoon as
cooler air aloft moves in overhead. The deep mixing will help
facilitate gusty northwest winds as well. The surface low will
track southeast from the Arrowhead to western WI by afternoon,
with some showers along and east of that track. Maintained chance
PoPs across western WI.

A continental polar airmass will settle in Friday night through
Saturday night with high pressure sliding south over the Great
Lakes. Friday night should be the coolest night of the next week
with lows in the 20s and low 30s.

Return flow begins Saturday night with a gusty southerly flow
taking hold Sunday into Monday night. This should bring
progressively warmer air in during this period. The high pressure
system will drive cool and dry air through the southeastern U.S.
and the eastern two thirds of the Gulf of Mexico until late Monday
when return flow finally begins in that region. This will
significantly modify low level moisture return northward into the
Upper Midwest and Great Lakes until just before the cold front
approaches Tuesday, or even after. In addition, a large cap due to
the elevated mixed layer and the dry inversion between 800 mb and
700 mb, will be in place throughout our time in the warm sector.
Even with a decently moist 50-60 kt LLJ Sunday night stretching up
into southern MN, it may be hard to get widespread convection
firing with the inversion displaced above the LLJ. That being
said, GFS and ECMWF do fire some showers and thunderstorms on the
nose of the LLJ late Sunday night, with quick weakening Monday
morning. Lowered PoPs into the low chance range during this
period.

Monday could be quite warm. The degree of warmth will depend on
early day convection and residual cloud cover. At the current
time, not expecting widespread convection and any convection that
does form should dissipate by late Monday morning with the loss of
the LLJ. ECMWF continues to bring +20 to +22C air at 925 mb into
Minnesota Monday afternoon. Mixing to that level would bring highs
into the low to mid 80s. The Canadian is even warmer, but the GFS
is cooler due to clouds and convection from south central MN to
northern WI. Raised highs into the upper 70s or lower 80s west of
I-35, but kept them in the mid 70s further east. Confidence is
quite high there will be breaks in the cloud cover and the
mechanical mixing should allow us easily to mix to 925 mb.

Cold front timing is still uncertain, it could occur Tuesday or
even Wednesday. The later it does pass through, the better the
odds are of seeing widespread thunderstorm activity and severe
weather with deeper moisture arriving. This would not be good for
already swollen rivers and wet agriculture fields.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1025 PM CDT Wed Apr 25 2018

Only change made to TAFs was to remove the VCSH mentions. The HRRR
has been trending drier with the precip along the front all night,
so removed what mentions we have. Timing for the FROPA still
looked good.

KMSP...It looks to be poor timing for the shift to northwest winds
as it will be occurring during the morning push. We look to go
from a 200 direction around to 330 over the course of about 2
hours. This 2 hour shift looks to begin around 12z or 13z.

/OUTLOOK FOR KMSP/
FRI...VFR. Winds NW 15G25kts.
SAT...VFR. Winds N, bcmg E late 5 kts or less.
SUN...VFR. Winds SSE 15G25kts.


&&

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

$$

SHORT TERM...JLT
LONG TERM...BORGHOFF
AVIATION...MPG



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