Area Forecast Discussion
Issued by NWS Twin Cities, MN

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

FXUS63 KMPX 091920

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
220 PM CDT Thu Jul 9 2020

.SHORT TERM...(This evening through Friday night)
Issued at 219 PM CDT Thu Jul 9 2020

Visible satellite imagery shows cloud cover across all but the far
west and northwest portion of the area. MCV over northern Iowa is
moving east-northeast, taking the main area of rain and embedded
thunderstorms with it. We will see some clearing from west to east
this afternoon as the MCV moves east, but mid and high clouds will
hang on for most locations, making eventual high temperatures a
tough call for much of the area. Allowed things to climb a bit
more across the west and central where clouds should thin, while
eastern portions of the area have either already seen their highs
or won`t until around sunset. Otherwise, look for improving
conditions tonight as the surface ridge over the Plains works into
the area. Friday will be warm but comfortable with low humidity.
Precipitation chances will return Friday night as the 850 theta-e
ridge works back into the area, and convection that forms over the
Dakotas drops southeast along the thickness gradient. The best
chance looks to be from west central into south central Minnesota,
but did allow for PoPs to get farther east late Friday night.

.LONG TERM...(Saturday through Thursday)
Issued at 219 PM CDT Thu Jul 9 2020

The guidance has come into somewhat better agreement in de-
amplifying the large scale upper flow across the central and
eastern CONUS as we work through the middle to latter part of next
week. Prior to that, we`ll initially see northwest flow give way
to a brief period of shortwave ridging at the start of the week.
Then things look to become fairly zonal, with multiple chances for
SHRA/TSRA during the second half of the week as quick moving
shortwave troughs move through the northern tier of the CONUS.
We`ll see some lingering chances for showers and perhaps a
thunderstorm Saturday as the upper trough drops into the area.
High pressure should then lead to mainly dry conditions from
Sunday through Monday before return flow sets up and brings
moisture and instability back by Monday night (along with chances
for showers and thunderstorms). With the more zonal flow
developing after that, differences in timing and location of
shortwaves and the main baroclinic zone result in varying chances
of precipitation for the second half of the week. This predictably
results in low PoPs encompassing much of the forecast from Tuesday
into Thursday. Did allow for a bit more of a dry forecast than the
NBM would suggest for Thursday, with the consensus of
deterministic guidance indicating a decent period of subsidence
and a drier airmass in the region. Plenty of ensemble members from
the GEFS and EPS suggest precipitation for Thursday, which leads
to NBM PoPs of around 20 percent, but knocked them down some to
go more in line with the deterministic guidance at this point (and
to avoid having the entire week look "wet", when in reality it
will be dry with a few chances for precipitation).


.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1244 PM CDT Thu Jul 9 2020

MCV over nothern Iowa will continue to move east-northeast this
afternoon, with precipitation and embedded convection enhanced to
its north and east. This will miss most TAF sites, with KEAU being
partially impacted for a time. VFR conditions will prevail, with
winds eventually becoming west and northwest across the area later
this afternoon and tonight as the surface frontal boundary moves

KMSP...Main uncertainty is with winds for the first few hours of
the forecast in terms of when they will shift around to the west
northwest. It should occur fairly quickly once the MCV to the
south gets east of the MSP`s longitude, but timing could differ
from TAF by an hour or two. Otherwise, conditions will generally
improve through the period.

Friday night...MVFR possible late with a chance of SHRA/TSRA.
Southeast wind 10 to 15 kt becoming southwest.
Saturday...MVFR possible with a chance of SHRA/TSRA. Southwest
wind 10 to 20 kt becoming northwest.
Saturday night...VFR. Northwest wind less than 10 kt.
Sunday...VFR. Northwest wind less than 10 kt.
Sunday night...VFR. Variable wind less than 5 kt.
Monday...VFR. Southeast wind increasing to 10 to 15 kt.




AVIATION... is the U.S. government's official web portal to all federal, state and local government web resources and services.