Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 221952

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
252 PM CDT SUN MAY 22 2016

.SHORT TERM...(This evening through Monday)
Issued at 252 PM CDT Sun May 22 2016

An abrupt change will occur across Minnesota and western Wisconsin
late tonight, and into Monday as moisture increases significantly in
the boundary layer, and aloft. Both PWATs and moisture transport are
above the 95 percentile, with some areas around the 99 percentile
late tonight and into early Monday. This is based on climatology
between 1979-2009. This basically means that when thunderstorms
develop, rainfall rates associated with these thunderstorms will be
locally high. I did add heavy rainfall in the forecast late tonight
for these conditions. Later forecast can re-access if rainfall rates
will continue to be high Monday afternoon, and Monday night.

Used CAMS to access timing of thunderstorms tonight in western
Minnesota where the best chance of widespread/organized convection
is likely. Further to the east in eastern Minnesota, the initial dry
airmass may hinder the onset of thunderstorms until after sunrise.
As for severe thunderstorms, and the latest information from SPC, a
few strong to severe thunderstorms will be possible Monday
afternoon. The severity of the storms will be based on recovery of
morning thunderstorms and the amount of instability. Several of the
WRF models do depict strong updraft speeds, but not necessarily
strong updraft helicity Monday afternoon along the cold front in
western Minnesota. Otherwise, Monday will be more humid with breezy
conditions along and ahead of the cold front.

.LONG TERM...(Monday night through Sunday)
Issued at 252 PM CDT Sun May 22 2016

An active weather pattern will ensue during the long term as
southwest flow dominates aloft with short wave energy emanating
from a deep trough in the west while a ridge strengthens in the

At this point, the best chances for showers and thunderstorms are
Monday night, Wednesday and then from late Friday through much of
the upcoming holiday weekend, associated with the short wave
energy. Unfortunately, the long term is littered with pops from
start to finish. The most widespread and perhaps heaviest rainfall
looks to be on Wednesday where a half inch to one inch is
expected. Overall, rainfall for the long term will likely total in
the two to locally three inch range.

Temperatures will continue above normal through the long term.
Tuesday will be the warmest day with highs from 80 to 85. Highs
thereafter will be more in the 75 to 80 degree range, which is
still some 5 to 10 degrees above normal. Lows will be in the
middle 50s to lower 60s through the period, which again is 5 to
10 degrees above normal.

As was the case yesterday, the focus for strong to severe storms
is Monday evening. More CAMS now cover this period and there are
two areas of interest. First, due to the incoming convection
late tonight and Monday morning, redevelopment late Monday
afternoon and evening will hinge on how quickly we can recover on
instability. A scenario seen in most of the CAMS today is for
convection to develop in two areas. The first is west central into
central MN toward evening. This is ahead of a surface trough and
also close to the right entrance region of the upper jet. A second
area develops during the evening from southeast MN through west
central WI. This area may be tapping some pretty good instability
due to the best heating during the late afternoon as well as where
the strongest low level wind field is in the evening. Hence, we
certainly can`t rule out a few strong to severe storms Monday


.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1225 PM CDT Sun May 22 2016

An isolated thunderstorm is likely in far western Minnesota for a
few hours this afternoon. However, most areas will remain dry and
not affect MPX taf sites. Quiet weather with VFR conditions is
likely through this evening across the rest of Minnesota and
western Wisconsin. Confidence has increased enough to continue
with VCTS and start it earlier at KAXN around 6z, and near
KSTC/KRWF by 9-10z. Elsewhere, confidence is too low to introduce
VCTS before 12z. CIGS will likely remain in the VFR range for
most of the TAF period, with the exception in western Minnesota
during the morning as MVFR CIGS are possible behind the initial
line of thunderstorms. Confidence is also high enough to warrant
VCTS for the rest of MN tafs, including west central Wisconsin by
the end of the taf period. Winds will continue to be gusty this
afternoon, but remain above 10 kts through the evening, and
overnight hours.


Confidence has increased enough that VCTS is warranted after 12z
with a period of 5-6sm in heavier showers and thunderstorms before
18z. Confidence is high that there will be a period of heavy
rainfall between 15-18z, but timing remains low, so no tempo
period is included. Winds will remain from the south-southeast
through tonight, and veer to the southwest Monday afternoon.

TUE...Mainly VFR. Chc TSRA/MVFR. Wind S 5 kts.
WED...Mainly VFR. Chc TSRA/MVFR. Wind light and variable.
THU...Mainly VFR. Chc TSRA/MVFR. Wind south-southwest 5 kts.


.MPX Watches/Warnings/Advisories...


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