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Area forecast discussion 
National Weather Service Twin Cities/Chanhassen Minnesota
254 PM CDT Tuesday Aug 23 2016

Short term...(this evening through wednesday)
issued at 245 PM CDT Tue Aug 23 2016

The short term concerns remain severe weather and heavy rain threat
this evening.

Water vapor imagery showing a well defined short wave lifting slowly
northeast over northwest Iowa. Most deterministic runs show this
lifting over southern Minnesota and western WI tonight. Some threat of
severe weather...mainly across south central Minnesota this evening as
the upper circulation moves through. Heavy rain will also be a
threat across mainly the southern 2 tier of zones along the Minnesota/Iowa
border through about 08z. Will continue to mention heavy rain
threat there through the evening...as latest hires cams a trending
a bit farther south.

The low level flow continues to be directed to the northeast
over the southeast portion of the area overnight as the front moves
into eastern Minnesota by 12z Wed. Clouds and shower remain over the
eastern areas into the morning with drying trend through the rest of
the day with passage of the front.

Long term...(wednesday night through tuesday)
issued at 245 PM CDT Tue Aug 23 2016

After Wednesday afternoon, the forecast continues to be straight
forward with a dry Thursday and Friday before chances of rainfall
increase again for the first half of the upcoming weekend. Next
week remains unsettled once again, but temperatures should remain
close to normal which is highs in the 70s to near 80 and overnight
lows in the 50s to near 60.

Models continue to hold together a fast west to east flow aloft
with embedded short waves through the next 5 days, with some
differences noted beyond day 5. In the wake of tonights system, a
cool Canadian air mass will settle across the region with highs 5
to 10 degrees below normal. Conditions remain favorable for a
widespread storm system with heavy rainfall affecting the upper
Midwest by late Friday night, and into Saturday. Timing and the
exact location of the heaviest rainfall remains in question, but
more than likely most areas will receive another bout of one half
to locally 1-2 inches. Based on the speed of this short wave and
the winds aloft, Sunday should be drier but I wouldn't be surprise
to see some instability showers across central Minnesota where the
cooler air mass/residual moisture will reside behind this system.

Again, next week remains unsettled with chances of rainfall almost
each day. Timing and placement will be problematic this early in
the forecast, but based on the overall flow pattern and moisture
levels, rainfall will again be likely. Although guidance does show
some 80s moving back into the forecast next week, with the amount
of moisture and unsettled conditions, will lean toward highs near
80. Howver, humidity levels maybe higher so expect heat indices to
rise once again.

Beyond day 7 in the forecast, a long wave trough is forecast to
deepen across the western part of North America, with a broad area
of zonal/southwesterly flow developing across the upper Midwest.
This may be a sign for continued unsettled weather and slightly
higher temperatures in the longer term.

&&

Aviation...(for the 18z tafs through 18z Wednesday afternoon)
issued at 1230 PM CDT Tue Aug 23 2016

Models are all fairly consistent on lifting Nebraska short wave
into southern Minnesota tonight and exiting with a surface front into
western Wisconsin Wednesday morning. Timing is an issue...with
activity beginning to move toward southwest Minnesota at this time.
Should move into krwf around 00z and northeast toward kmsp by 02z-
03z. Thunder will be a threat with attendant IFR/MVFR cigs with
fog becoming an issue late ahead of front later tonight. Expect
cigs to lift rapidly behind front from east central/MN and west
central Wisconsin between 12z-18z Wed.

Kmsp...best potential for storms will be between about 02-07z and
perhaps late tonight with fropa. VFR conditions expected until
then with gusty winds to 25 kt...with cigs lowering to MVFR and
possible IFR cigs late tonight as cold front approaches. Still
expect cigs to improve through the morning Wednesday after fropa.

/Outlook for kmsp/
Wed nite...VFR wind NW 5-7 kts.
Thu...VFR. Wind northwest 7-10 kts.
Fri...VFR. Wind south-southwest 5-10 kts.

&&

Mpx watches/warnings/advisories...
WI...none.
Minnesota...none.
&&

$$

Short term...dwe
long term...jlt
aviation...dwe

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