Area Forecast Discussion
Issued by NWS Twin Cities, MN
FXUS63 KMPX 290340 AAB
Area Forecast Discussion...UPDATED
National Weather Service Twin Cities/Chanhassen MN
1040 PM CDT THU JUL 28 2016
.SHORT TERM...(This evening through Friday)
Issued at 310 PM CDT Thu Jul 28 2016
Surface analysis this afternoon shows a surface low pressure
center near the central IL/IN border with a warm front extending
eastward into the Mid-Atlantic and New England states along with a
trailing cold front sagging southwest into the Central Plains.
There is also an inverted trough feature extending northwest along
the Mississippi River from the low and it is this feature which
has helped develop scattered light rain showers over southeastern
and south central parts of the coverage area today. In addition to
the surface trough, a broad upper level trough in the 700-500mb
levels is dropping southeast over the region, allowing for deeper
moisture and added lift to increase shower coverage.
With both the surface and upper level features moving off to the
southeast this evening, the chances for additional precipitation
will diminish so have showed such a trend for southeastern
portions of the coverage area. High pressure will then filter in
from the northwest behind the departing low pressure system
overnight through Friday as will small bubble ridging aloft within
the northwest flow. This will allow for partial clearing through
the rest of today on through tomorrow and slightly warmer
temperatures for tomorrow. Where highs today were stuck mainly in
the upper 60s to mid 70s (save for some upper 70s in far western
MN), highs on Friday will range from the mid 70s to around 80
degrees. In between, for tonight, lows will be seasonably cool,
mainly in between 50 and 60 degrees.
.LONG TERM...(Friday night through Thursday)
Issued at 320 PM CDT Thu Jul 28 2016
Not too many changes (Friday Night/Sunday Only) in the extended
period with a generally dry period from Friday night through
Sunday. An isolated shower or storm can not be ruled out in far
western Minnesota and portions of southeast/south central
Minnesota as residual moisture and return flow from the southeast
commences Saturday night/Sunday.
The main story continues to be the possibility of another heat
wave early next week as an upper ridge builds across the Rockies,
and into the Northern Plains/Upper Midwest. As with previous
discussions, the core of the hot air mass will remain south of
Minnesota and Wisconsin, but humidity levels will definitely rise
as dew points average in the 70s by Mon/Tue/Wed.
Due to the core and the center of the upper ridge further to the
south then the last heat wave (July 20-22), our region will likely
have a stronger west to east flow aloft. Depending upon the
strength of the cap as 70h temperatures rise into the 12-14C
range, MCSs will likely form across the Northern Plains, and move
quickly eastward during the evening/overnight period across the
Upper Midwest (Mon/Tue/Wed). Timing and placement of these MCSs
will be problematic this far into the future. However, the setup
has a similar pattern (Typical MCSs in the Upper Midwest) with
strong shear aloft, and ample CAPE. Both the EC/GFS models are
similar on the evolution of the long wave trough moving/strengthening
across southern Canada next week. This has led to a stronger west
to east flow along the northern tier of the United States. With
this type of flow, and the center of the upper ridge further to
the south, the heat wave will likely be short lived and only last
a day or two (Tue/Wed). Past Wednesday, and due to the stronger
west to east flow aloft becoming more west-northwest, another
significant frontal boundary will likely move southward over the
Upper Midwest, cooling down the atmosphere late next week.
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1040 PM CDT Thu Jul 28 2016
VFR conditions expected through the period. A few showers have
popped up near EAU this evening, but should diminish in the next
couple hours. The clearing line will continue heading southeast
/OUTLOOK FOR KMSP/
Sat...VFR. Winds SE 5 kts.
Sun...VFR. Winds SE 5-10 kts.
Mon...Mainly VFR. Chance MVFR/TSRA late. Winds SE 5-10 kts.