Area Forecast Discussion
Issued by NWS Twin Cities, MN

Home | Current Version | Previous Version | Graphics & Text | 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

908
FXUS63 KMPX 240848
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
348 AM CDT Fri Mar 24 2017

.SHORT TERM...(Today and tonight)
Issued at 348 AM CDT Fri Mar 24 2017

Short term concerns are thunder threat this morning and overall
shower trend into the afternoon.

We did have an area of thunder move across far southern MN early
this morning...with some small hail indicated along the I90
corridor. As this area of thunder raced into southeast MN...another
area of isolated thunder developed west of the metro along a
boundary of mid level frontogenesis and -EPV.  This should work east
early this morning...taking the thunder threat with it. The rain
showers should continue through the morning across the southeast
cwa...before tapering this afternoon. Will trail pops off some to
the southeast. Along with the rain and clouds...some fog is also
present where the boundary layer became saturated.  This should
gradually improve through the morning. With clouds and rain much of
the day across the region...temperatures are expected to warm
through the lower and mid 40s.

The upper low remains to the south of the area tonight...and will
continue threat of light rain to the southern cwa. Some drier air
will work into the northwest cwa as high pressure begins to shift
east. This will thin the clouds over that area tonight and overnight
lows are expected to cool to 30 to 35.


.LONG TERM...(Saturday through Thursday)
Issued at 348 AM CDT Fri Mar 24 2017

A parade of short waves will rule the long term. Model consensus
is high on the first wave, which will be located over MO at the
start of the long term. This feature will move slowly northeast to
the central Great Lakes by Monday. As it does so, some light
rain/showers will occur across eastern and southern sections of
the FA. Due to the northeast winds and cooler nighttime
temperatures, any precipitation that falls Saturday night/early
Sunday across central MN and northern areas of WI will be a
wintry mix. At this point, precipitation amounts look to be quite
light.

An elongated surface ridge will pass across the local area on
Tuesday. This has been well forecast for several days now by the
deterministic models and is the nicest day on the long term with
regard to sky cover (mostly sunny).

Disagreement continues tonight on the handling of the next
shortwave for Wednesday and Thursday. The GFS continues to hold
this feature to our south, with the northern edge of the
precipitation shield only reaching northern IA. This has been the
case now for several nights while the ECMWF lifts this wave into
our area. Part of the answer for this difference in movement is
likely tied to yet another strong short wave/closed low/ moving
into the western U.S. during the aforementioned time. The incoming
wave is farther north on the ECMWF versus the GFS, and is the
kicker for the Plains short wave and why it moves differently
between the two solutions. In addition, the ECMWF has a stronger
northern stream wave moving through our area over that of the GFS
during this same time. The Canadian has the northern wave but
keeps the southern feature down over Texas. So at this point only
some small pops were used for Wednesday afternoon and night to
account for precipitation chances with the northern stream short
wave.

Few changes were made to the temperatures being forecast in the
long term from the past several cycles. Middle to upper 40s will
be common for highs Saturday and Sunday with highs in the lower to
middle 50s from Monday onward. Lows will be pretty much in the
middle 30s with the exception of Saturday night. Overall, the long
term will average out about 7 or 8 degrees above normal.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1055 PM CDT Thu Mar 23 2017

Stable precip in the form of rain and drizzle has broken out north
of the 850mb warm front from western MN across the Twin Cities
into WI. This secondary warm front (the main surface warm front
was crossing I-80 at 11pm) is also the demarcation line for
IFR/MVFR cigs to the north and VFR south. It`s about as far north
as it is going to make it, with the ra/dz helping to reinforce the
clouds/boundary layer moisture, so will keep MSP/EAU MVFR or
lower. Thunderstorms have broken out across Neb and are quickly
spreading into NW IA. These storms though look to come up to
about as far NW as Mankato/Red Wing line, so removed TS mentions
from MSP/RWF. Rain will linger through much of Friday morning at
RWF/MSP/RNH/EAU, but precip the remainder of the period will
remain southeast of AXN, with STC on the northern fringe. Lower
confidence in cig improvements Friday afternoon. GFS/NAM soundings
though show low moisture cleaning out pretty aggressively at MN
terminals. Given extent of current low clouds, was hesitant to be
too quick in getting rid of them and was hesitant to go VFR all
the way to MSP.

KMSP...Looks like any thunder will remain south of the field,
though not by much. With dz/ra breaking out, think the VFR trend
that came up from the south will stop on the doorstep of MSP, with
MVFR becoming IFR cigs being dominant into Friday morning. We`ll
also keep light precip going through the morning before drying out
in the afternoon. For now, kept MVFR cigs going through the
morning, though the GFS/NAM would say MSP could go VFR around 00z.

/OUTLOOK FOR KMSP/
Sat...Chc MVFR -RA. Wind NE 5-10 kts.
Sun...Chc MVFR. Wind ENE 5 kts.
Mon...Chc MVFR Early. Wind N 5 kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&

$$

SHORT TERM...DWE
LONG TERM...RAH
AVIATION...MPG



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