Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Twin Cities/Chanhassen Minnesota
324 PM CDT Tuesday Oct 6 2015
Short term...(this evening through wednesday)
issued at 315 PM CDT Tuesday Oct 6 2015
Relatively quiet short term period ahead. Band of middle level clouds
will continue to erode and progress south of the area tonight...as
high pressure works in from our northwest. Cooler temepratures are
expected overnight...with middle 30s looking likely across parts of
central Minnesota...so a frost advisory was issued for that area. The
center of the surface high will remain north of US tonight...so the
coldest air will be there under the clear and truly calm conditions.
Winds will be light...but enough to generate a little
mixing...especially further south. Much of the rest of our area
will see temperatures in the upper 30s to lowers 40s.
The surface ridge axis will work to our east tomorrow...so we will
see winds turn around to the southeast...and temperatures rebounding
into the 60s. The next system set to impact our area will be
approaching from the west by late tomorrow afternoon...so indicated
slight chance and chance probability of precipitation pushing into western Minnesota later tomorrow
afternoon. Cloud cover will be on the increase through the day from
the west ahead of said system. The majority of the precipitation will occur
beyond the short term forecast period...which is covered in the long
term portion of the discussion.
Long term...(wednesday night through tuesday)
issued at 315 PM CDT Tuesday Oct 6 2015
Longer term concerns remains timing of precipitation across the
area with short wave Wednesday night/Thursday and the warming
trend for the weekend.
Deterministic models fairly consistent now with movement and
timing of the front moving across the area early in the period.
Strongest forcing is channeled north into central and northeast
Minnesota. Moisture transport maximizes mainly after 06z Thursday and exit to
the east by 18z Thursday. Quantitative precipitation forecast amounts around one half inch look likely
into central Minnesota with lesser amounts forecast near the Minnesota/Iowa
border. We will continue categorical probability of precipitation over the northern half
of the County Warning Area as it moves through as well. Marginal instability with
best lifted indice's forecast to around minus three along the front...so we
still could see at least an isolated thunder threat and we
continued that mention into Thursday morning tot he east.
Northwest winds are forecast to increase to 15 to 25 miles per hour over
much of the west and south in the wake of the system Thursday.
Clouds will clear out slowly from northwest to southeast into
Thursday night and winds are expected to remain overnight. This
should hold temperatures in the 40s Wednesday night. Cool day for
Friday with the high moving across the area. Winds should be light
with a mainly sunny sky.
Models continue their trend of significant warming out ahead of
the next surface frontal system. Southwest winds develop again
Saturday spreading a warm front east over the County Warning Area. We should see
readings warm through the 70s across the Minnesota County Warning Area Saturday
afternoon. Straight mix down temperature forecast had readings
85-90 in Minnesota portion of the area and readings around 80 into west
central Wisconsin for Sunday afternoon. Dont believe we will get
that warm but 80s should occur over much of Minnesota County Warning Area with near
record highs possible.
Some model discrepancy in timing/strength of the next system
moving through into early next week. Will follow guidance for now
and hold off on the next small rain chance until next Tuesday with
high only cooling back into the 60s.
Aviation...(for the 18z tafs through 18z Wednesday afternoon)
issued at 102 PM CDT Tuesday Oct 6 2015
High pressure pushing in from our northwest will force current
cloud cover to dissipate and move southeast of the area through
tonight. Light winds out of the northwest will gradually turn
northerly then easterly as the ridge axis moves to our east
tomorrow. High clouds push in quickly from the west tomorrow
afternoon...ahead of approaching low that will bring its chance of
precipitation beyond the current forecast period.
Kmsp...no change from main discussion. VFR throughout the
period...any chance of precipitation holds off until Wednesday night.
/Outlook for kmsp/
Thursday...MVFR ceilings/visibilities with rain showers/ts early. Winds SW 10-20 knots
Thursday night...MVFR ceilings possible. Winds northwest 10-20kts. Winds northwest 10 to
15 knots decreasing to 5 to 10 knots.
Friday...VFR. Winds northwest 7-10kts.
Sat...VFR. Winds SW 20-25 gusts to 30kts.
Minnesota...frost advisory from midnight tonight to 8 am CDT Wednesday for