Scientific Forecaster Discussion
fxus63 kmpx 272122
Area forecast discussion
National Weather Service Twin Cities/Chanhassen Minnesota
422 PM CDT sun may 27 2018
Short term...(this evening through monday)
issued at 422 PM CDT sun may 27 2018
A complex temperature forecast has been ongoing all day with the
multiple outflows, extensive high clouds, and showers/storms
across central Minnesota. Finally, they are beginning to dissipate
and temperatures are responding very quickly where clearing is
occurring. Temps have risen into the lower 90s as far north as
Princeton and Cambridge with a brief period of sunshine, so left
the heat advisory for today as is. Readings have climbed into the
upper 90s where sun has been prevalent for a few hours from west
central to south central Minnesota, and even in parts of Wisconsin. We
shouldn't have problems heating for at least the next couple hours
and am still expecting low to mid 90s as far northeast as the
Metro early this evening.
Temperatures won't cool off as much tonight as they did last
night, and they may not drop below the mid 70s in the Metro.
Extended the heat advisory through tonight in the Metro, but will
allow it to drop off at 8 PM for outstate areas with readings in
the 60s expected.
Monday is likely to be the hottest day of the stretch. There are
many readings upstream in the upper 90s to lower 100s this
afternoon. Models seem to be in pretty good agreement in bringing
highs close to 100 Monday south of a slowly sagging cold front.
Dew points will also be higher, especially in the shallower mixed
areas north of the cold front. Issued an excessive heat watch for
the Metro Monday afternoon where heat indices may reach the low
100s and posted another heat advisory for most of central and
southern Minnesota. The advisory may need to be expanded east
into Wisconsin more if the current forecast holds. However, a few
models bring another thunderstorm complex southeast across northern
Wisconsin Monday morning, which may allow the cold front to
accelerate southwest a bit quicker through those areas. Hence, the
Additional isolated thunderstorms could develop in the hot and
well mixed atmosphere across central and southern Minnesota late
Monday afternoon. These should not have too much of an impact on
temps as they develop when the highs are being reached.
Long term...(monday night through sunday)
issued at 422 PM CDT sun may 27 2018
Upper-level ridging slides east on Tuesday with temperatures
moderating a few degrees from this weekend but still remaining in
the low-80s to upper 90s. For many areas this will be the 5th or 6th
90 degree day in a row which is a stretch of heat not seen before in
may. As the ridging weakens a shortwave trough approaches from the
west & given the warm & unstable atmosphere, looks to generate
enough forcing to kick off a round of scattered showers &
A more likely chance for thunderstorm comes Wednesday as the
shortwave deepens & potentially interacts with the remnants of
Alberto. For now, it appears that Alberto will begin curving east
before it reaches the upper Mississippi Valley & thus we're only likely
to see an increase in moisture with precipitable water values increasing to around
1.5". Increased precipitation chances across eastern Minnesota & west-
central WI Wednesday night as models have consistently shown at least
some moisture from Alberto streaming into the area. How much
rainfall we will see is still in question. The current track would
keep the bulk of the moisture & forcing from Alberto east of our
area, but if the shortwave is a little quicker & pulls Alberto
further west we could see more of a heavy tropical-like event with
an increased flooding threat.
Rain chances slide east into WI on Thursday with a general drying
trend Thursday evening into Friday as weak ridging builds back into
the area. Another active weather pattern looks to set up next
weekend as we sit under the northern periphery of the Central Plains
ridge with multiple shortwaves rounding the top over our area.
Aviation...(for the 18z tafs through 18z Monday afternoon)
issued at 1257 PM CDT sun may 27 2018
VFR conditions will prevail throughout the period with an area of
decaying thunderstorms near stc further continuing to weaken.
Winds will be northwesterly for a few hours at stc,msp,rnh, & eau
in the early afternoon as the outflow boundary from these storms
moves east. Otherwise, winds are expected to be southeasterly this
afternoon, become southerly overnight, and generally out of the
west through Monday morning. High clouds will diminish somewhat
this afternoon but will increase in coverage again tomorrow
Kmsp...tricky winds this afternoon with the outflow boundary over
the area. Expected to remain northwesterly to northerly through
early afternoon, and then gradually become more southeasterly.
Thunderstorm chances increase towards 00z Monday but since this is
at the very end of of the taf period, will keep any mention of
precip to the afd for now.
/Outlook for kmsp/
Tuesday...mainly VFR. Chc -shra/-tsra. Wind S 10g20 kts.
Wednesday...mainly VFR. Chc -shra/-tsra. Wind S 10g20 kts.
WI...heat advisory from 1 PM to 7 PM CDT Monday for wiz023-024.
Minnesota...heat advisory until 8 PM CDT this evening for mnz051>059-064>067-
Heat advisory from 1 PM to 7 PM CDT Monday for mnz051>059-
Heat advisory until 1 PM CDT Monday for mnz060>063-068>070.
Excessive heat watch from Monday afternoon through Monday
evening for mnz060>063-068>070.