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Area forecast discussion 
National Weather Service quadrant cities Iowa Illinois
1155 PM CDT Sat Oct 3 2015

issued at 1002 PM CDT Sat Oct 3 2015

With the setting sun...the westward push of the low clouds has
accelerated. As of 10 PM...the leading edge of the deck with
bases around 3000 to 4000 feet deck was along to just west of the MS
river. Looking at VAD wind profile 925 mb winds of 25 to 30 kts
from the east-NE all the way back to Lake Michigan...where ceilings were lower
and radar showed moisture advecting in from the south...this trend
should continue. Between high clouds advancing from the west and
low clouds spreading eastward...most of the forecast area should
become overcast by morning and may remain cloudy through Sunday as
well. Have adjusted the forecast for winds remaining stronger this
evening along with cloud trends. Lows were not adjusted...but if
the current cloud trends continue...mins in the upper 30s in the
northwest may be too cool.


issued at 327 PM CDT Sat Oct 3 2015

Satellite shows very energetic flow pattern across Continental U.S. With an
upper level ridge over the central U.S. Being squeezed by broad
upper level troughing in the west and cut-off low in the southeast
involved in complex interaction with Hurricane Joaquin. Large
expanse of surface high pressure was found over northern Great
Lakes and Ontario with broad easterly flow resulting in
continuation of dry and seasonably cool temperatures across the region.
Little change is expected next 24+ hours as pattern largely remains
blocked until Joaquin pushes well east of the Atlantic coastline.


Short term...(this evening through sunday)
issued at 327 PM CDT Sat Oct 3 2015

Atmospheric river of moisture with connection to Hurricane Joaquin
advancing westward through the Ohio Valley. Interaction with southeast
cutoff low is pulling moisture westward and will result in a gradual
increase and lowering of clouds from east to west tonight except
possibly far west/northwest County Warning Area where mainly just some thinning cirrus as it
advances from plains into upper level ridge. Cant totally rule
out some patchy drizzle occurring from within the lower clouds
along and mainly east of the Mississippi River where forecast
soundings would indicate some shear and copious dry air above the
clouds. Lows tonight will be modulated by cloud cover and
generally expect warmer readings east (upper 40s to lower 50s)
where more cloudiness for longer duration... while coolest in the
west (around 40/lower 40s) where skies mainly clear or late arrival
of clouds.

Sunday... will continue with considerable stratus in moistening
easterly flow resulting in partly to mostly cloudy skies. This
along with easterly winds around 10 to 15 miles per hour will limit highs to
around 60 to 65. Although... based on observation beneath clouds today to
our east would not be surprised to see some areas stay in the
upper 50s for highs... which would be most favored near to east of
the Mississippi.

Long term...(sunday night through saturday)
issued at 327 PM CDT Sat Oct 3 2015

Main forecast concern for the long term forecast are the prospects
for rain and possible isolated thunder towards the middle of the
workweek. The last few runs of the GFS and European model (ecmwf) have been
relatively consistent with the placement of the surface low at 12z
Thursday across Minnesota. Main questions remain on the chances for
moisture return and the chances for thunder.

The beginning of the period starts out with a slug of moisture over
the area. Monday morning NE flow off Lake Michigan and a increasing
surface moisture may interact with a h92 front across the area. This
could lead to some isolated showers across far eastern zones of the
County Warning Area. As such...went with a 15% pop in far NE zones of the County Warning Area. Surface
high pressure will remain in place across the area as 500 mb ridging
becomes more Oblong shifting into northwest flow. This zonal ridging will
aid in warming temperatures and moisture return across the area. A wave
transversing through out the northwest flow will lead to the chances of precipitation
on Wednesday night through Thursday across the area. At this time...current
indications are that isolated thunder is possible Thursday
afternoon. The overall wave looks to be weak and overall
instability is suspect...but it appears that the shear associated
with this system is lower than one would typically like to see for
severe weather to occur this time of year.

After this wave...we stay in a northwest flow pattern. Ripples in this flow
keep chances for precipitation around.


Aviation...(for the 06z tafs through 06z Sunday night)
issued at 1155 PM CDT Sat Oct 3 2015

Low clouds will continue to flow westward from the Great Lakes
and Ohio Valley region as moisture flows into the region overnight
into Sunday. MVFR ceilings at mli...dbq and brl will spread into the
Cid area shortly after midnight...with ceilings then continuing to
gradually lower from east to west through the night. Current
forecasts maintain MVFR ceilings...but there is a potential for ceilings
to drop at least briefly below 1000 feet with possible 4 to 6sm in
fog early Sunday morning. Ceilings will likely increase some during
the day Sunday...but likely remain in MVFR range.


Dvn watches/warnings/advisories...


short term...McClure
long term...Gibbs

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