Rochester, Minnesota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

498
FXUS63 KARX 122348
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
548 PM CST Tue Nov 12 2024

.KEY MESSAGES...

- Variable clouds tonight with rain chances increasing for
  Wednesday, especially during late afternoon and evening hours.
  Amounts continue to look light from a few hundredth to two
  tenths of an inch.

- Seasonably warm temperatures into the weekend with small rain
  chances Saturday night into Sunday (5 to 30%)

- Potentially active weather mid next week with rain or,
  depending on the storm track, accumulating snow (25 to 45%
  probability for accumulating snow late Tuesday or Wednesday).

&&

.DISCUSSION...
Issued at 142 PM CST Tue Nov 12 2024

Overview:

Surface high pressure was centered over the area at 19Z,
however some low level moisture has been moving northwestward,
creating variable partly cloudy to cloudy conditions.
Temperatures were held to the 40s with increasing southeast
winds, especially west of the Mississippi River with gusts 20 to
30 mph. Early afternoon water vapor satellite imagery, heights,
and lightning showed a ridge over the Upper Mississippi Valley
region with a longwave trough over the Rockies. There was a
tropical connection for the mid and high level moisture from the
Pacific Ocean across Baja into the Southern Plains and
Tennessee River Valley.

Variable clouds tonight with rain chances increasing for Wednesday,
especially during late afternoon and evening hours:

Main forecast challenge overnight will be the stratus with the
forecast soundings and cross sections showing a healthy amount
of 925mb relative humidity. The HREF synthetic cloud cover tries
to break up some of these clouds this evening with some patchy
mid clouds increasing. The latest satellite image has some of
the clouds with wider spacing and our local cameras show they
are very flat...thus should see improvement in the lows clouds
for some occur overnight. The 400-300mb moisture increases to
95%+ by 12Z, so look for clouds to overspread the region
Wednesday.

Moisture transport vectors increase across the Missouri River
Valley/Southern Plains/Lower Mississippi Valley region Wednesday as
a mid-tropospheric trough moves through the Plains.  Through the
day, the 850mb moisture transport weakens, however continues
strongly across areas to the southeast from the Tennessee River
Valley toward Illinois. The closed low is progged to track
across the forecast area through Wednesday night and could
linger into early Thursday. For the onset...the initial top down
moistening is going to take a while. A strong 80 to 105kt jet
is forecast to move into the region, however the pockets of
stronger upper level divergence appears to be coming out in
pieces; an area to the north across parts of Minnesota, an area south
more in Illinois, and eventually across the forecast area.
Cross sections show mid-level moistening through the day and
some sprinkles with deeper moistening from west to east after
18Z. The latest HREF guidance continues to slow down the onset
of the precipitation with spotty precipitation through
21Z...then more widespread precipitation moves from west to east
across the forecast area especially through 09Z. Rainfall
amounts continue to be on the light side and vary from 0.03 to
0.20"...with the HREF probabilities for a wetting rain have
decreased to less than 10% for the chimney area to 70% for parts
of southeast MN/northeast Iowa, and southern WI south of Prairie
du Chien. Still some low probabilities (0 to 30%) for 0.25" or
more. Probabilities increase greatly though to the west of
Minneapolis and east of Rockford, IL.

Seasonably warm temperatures into the weekend with small rain
chances Saturday night into Sunday (5 to 30%):

Ridging builds into the region Thursday and Friday as a trough over
the West Coast advances eastward to the Intermountain region and
gradually the Northern Plains this weekend.  The bulk of the energy
with this system lifts northward into Canada, however, a pre-frontal
trough is followed by a cold front Tuesday.  There are some hints a
precipitation developing with the pre-frontal trough.  The
deterministic runs are still mainly dry for Sunday, but the new
12.12Z EC tries to squeeze out some precipitation Saturday
night. About 1/3 of the ECE ensembles show very light
precipitation, but only one or two of the GEFS ensembles has
precipitation.

Potentially active weather Monday night through midweek with
strong winds and rain/accumulating snow (12.00Z LREF has 25 to
45% probabilities for accumulating snow Tuesday or Wednesday:

The southwestern extent of the trough is a closed low over southern
California Sunday.  This area of low pressure is forecast to lift
northeast ahead of a deepening trough moving into the Pacific
Northwest. 12.00 cluster analysis shows difference in the amplitude
and position of the ridge. This will be a system to watch as it
looks like a wetter system as the trailing trough tries to
merge somewhat with the leading trough that slows down with on
and off precipitation from late Tuesday or Wednesday possibly
through Thursday night. Strong winds could accompany the system. In
addition, half the GEFS members have accumulating snow.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 540 PM CST Tue Nov 12 2024

Confidence in the ceiling forecast for the TAF period is quite
low given that the models have more low-level moisture present
than what current observations would indicate. A narrow ribbon
of MVFR stratus has been decaying all day and advecting to the
northwest, trends that are expected to continue this evening.
Have gone clearer for cleanings tonight and into Wednesday
morning ahead of our next system that arrives during the day.
The potential for afternoon showers has been trending downward,
but did still include non-restrictive PROB30 showers at the end
of the TAFs. Winds will remain from the southeast at around
10-15 kts through the period.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.

&&

$$

DISCUSSION...Zapotocny
AVIATION...Skow