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Area forecast discussion 
National Weather Service Duluth Minnesota
1158 PM CDT Friday may 22 2015

Update...
issued at 1158 PM CDT Friday may 22 2015

Updated aviation section below. Scattered showers mainly just
north of the Canadian border this evening expected to continue for
the rest of the night. For the most part they should stay
north...but cannot rule out some sprinkles into the
borderlands...and have updated the forecast for this.

Update issued at 644 PM CDT Friday may 22 2015

A quick update for latest trends. Updated aviation section below.

&&

Short term...(this evening through saturday)
issued at 354 PM CDT Friday may 22 2015

High pressure and clear skies are the main story for tonight and
early Saturday. Initial cirrus shield from surface low over
central Nebraska was advancing north through southern Minnesota
late this afternoon...and gradually increase clouds tonight and
early Saturday across my south. Next challenge is timing initial
frontal passage on Saturday afternoon. NAM bufr sounding from brd
suggest 200-500 j/kg of SBCAPE by late afternoon just ahead of the
passage of the warm front. Carried previous shifts low chance probability of precipitation
across my south with a potential for a rumble of thunder.

Temperatures will trend warmer through my period with mins in the low to
middle 40s tonight and highs on Saturday in the low to upper 70s.
Trended closer to the bias corrected MOS guidance as that has been
performing well.

Long term...(saturday night through friday)
issued at 354 PM CDT Friday may 22 2015

Upper level and surface ridging cover the forecast area Saturday night.
Only the NAM is trying to bring in rain over the southern portions
of the area. GFS/Gem/ECMWF have backed off. Will follow the
consensus and have removed the probability of precipitation Saturday evening and lowered
significantly overnight so probability of precipitation are aligned over the southern edge
of the area. Minimal instability so no thunder mention. While the
ridging is hanging tough on Sunday...short wave energy is trying to
undercut the ridge. GFS is too far north and too fast with
quantitative precipitation forecast...followed by the NAM. Prefer a blend of the Gem/European model (ecmwf) for probability of precipitation.
Thermodynamic profiles do not support a mention of thunder and have
removed. Ridging is finally overcome Sunday night by a closed upper
low drifting into the northern plains. Embedded pieces of energy
will rotate from this low over the region warranting higher probability of precipitation.
Best instability will be found over the southern half of the area
Sunday night and have isolated thunder mentioned. The closed upper low
opens into a long wave trough on Monday. More energy will eject out of
the trough on Monday resulting in higher probability of precipitation and a better chance of
thunderstorms as thermodynamic profiles suggest. This upper trough
becomes virtually stationary over the upper Mississippi Valley
through Thursday. This will keep impulses moving over the area from
time to time and probability of precipitation are in place.

&&

Aviation...(for the 06z tafs through 06z Saturday night)
issued at 1158 PM CDT Friday may 22 2015

VFR conditions continue with light southwest winds less than 10
knots. Middle clouds to spread into the area from the southwest after
18z Saturday...to be followed by some rain showers arriving in
vicinity of kbrd after 03z. Have just gone with vcsh for now as
confidence is low and coverage to be pretty sparse.

&&

Preliminary point temps/pops...
dlh 46 72 48 68 / 0 10 10 10
inl 47 77 45 78 / 10 0 0 0
brd 46 70 50 68 / 0 20 10 30
hyr 43 71 48 70 / 0 10 20 30
asx 43 74 46 72 / 0 0 10 10

&&

Dlh watches/warnings/advisories...
Minnesota...none.
WI...none.
Ls...none.
&&

$$

Update...le
short term...huyck
long term...gsf
aviation...le

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