NWS Forecast Discussion

FXUS63 KMPX 171058

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
558 AM CDT Wed Aug 17 2022

.DISCUSSION...(Today through Tuesday)
Issued at 414 AM CDT Wed Aug 17 2022


- Unsettled weather for the next several days.

- Weak disturbances will result in a somewhat chaotic distribution of
  showers and storms until the stronger disturbance arrives Friday.

- Severe weather is not expected. Isolated instances of nuisance
  flooding are possible.

Isolated showers early this morning across northern MN and northwest
WI are not moving much. However, weak instability will spread south
this morning and weak embedded shortwaves in the northerly flow
should allow these showers to build south later this morning. There
may be a lull early afternoon before peak heating/instability develop
in advance of another wave which should result in greater coverage
across eastern MN into northwest WI. Weak MBE velocities will lead to
slow moving cells which may send out outflow boundaries that spark
additional activity. Continued development will likely occur tonight,
mostly along and east of I-35.

Coverage will increase Thursday and peak Thursday night and Friday
with the arrival of a large upper low. Stronger forcing and
sufficient instability will facilitate widespread shower and
scattered thunderstorm development. MBE velocities will remain AOB 15
kts, and pwats will rise to about 1.5 inches. Locally heavy rainfall
will be likely, but the footprint of excessive rainfall should be
low enough to preclude more than isolated flooding concerns.

The upper low will linger into Saturday, then exit to the southeast
Saturday night. High pressure builds in early next week and
temperatures will remain near normal.


.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 540 AM CDT Wed Aug 17 2022

Have added PROB30s for -TSRA at STC, MPX, and RNH for late this
afternoon into early evening. Forecast soundings show some uncapped
instability with a few CAMs developing a small line of showers and
storms in central to eastern MN and extreme western WI. More showers
look to occur across our eastern terminals early Thursday morning.
Thunderstorms may also be possible at RNH and EAU so have added
another PROB30 for early Thursday morning at these terminals. Aside
from when and where storms may occur, VFR conditions are likely the
entire period. Winds will generally oscillate between south-
southwesterly and southerly near 5 knots.

KMSP...Kept PROB30 for the chance of thunderstorms from 23-04z today.
Reduced visibilities to MVFR are likely if a storm were to occur.
Rain showers look probable from about 10-14z Thursday morning. Some
showers may linger later into the morning so have added another
PROB30 from 14-18z Thursday.

Thu...VFR. -SHRA likely, chc TSRA late aftn thru overnight. Wind SW
      5-10 kts.
Fri...Periods of -SHRA/MVFR chc -TSRA. Wind S 5-10 kts.
Sat...MVFR/SHRA likely. Wind SE 5-10 kts.




NWS MPX Office Area Forecast Discussion

Script by Ken True @Saratoga-Weather.org