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Area forecast discussion 
National Weather Service quadrant cities Iowa Illinois
1235 PM CDT Tuesday Oct 21 2014

Synopsis...
issued at 222 am CDT Tuesday Oct 21 2014

At 3 am CDT...a back door cold front had advanced southward and
extended from southern Iowa...through the southern forecast area
through central Illinois. Early morning temperatures ranged from
the upper 30s to lower 40s behind the front...to the upper 40s
south of Highway 34.

&&

Short term...(today and tonight)
issued at 222 am CDT Tuesday Oct 21 2014

Temperatures will be the main forecast challenge in the short term
period.

In the near term...some valley fog has started to develop early
this morning and have included patchy fog along the Mississippi
from Dubuque down to Clinton. Expect a cooler day with surface
high pressure overhead and NE low level winds. Have favored a
rough split between the warmer mav and cooler met guidance...which
yields afternoon highs from the middle 50s northeast to the lower 60s
southwest.

For tonight...a clear sky and light easterly wind should allow
temperatures to dip into the lower 30s northeast to near 40
southwest. Frost will be favored north of Interstate 80...although
due to the previous end of the growing season...will not mention
in forecast. River Valley fog will be favored across the northeast
fringe of the forecast area...co-located with the lightest winds.

Long term...(wednesday through monday)
issued at 222 am CDT Tuesday Oct 21 2014

Forecast focus on better rain chances on Thursday than earlier
thought and then a nice warm-up this weekend.

Wednesday night through Thursday night...operational models coming
in much more aggressive with the upper level trough that pushes into
the Midwest. Water vapor loops do show this rather impressive wave
currently entering the Great Basin. While Gulf moisture looks shut
down the trough will bring with it Pacific moisture. Forecast
sounding are more aggressive with saturating the column compared to
previous runs due to the trough will be stronger. Precipitable
waters are prognosticated to increase on Thursday to around 1.20 inches
which still seems a bit too high. However...rainfall amounts of 0.1 to
0.5 inches seem reasonable and thus have raised probability of precipitation into the likely
category on Thursday over most of the County Warning Area. Will bring in chance probability of precipitation
in our western County Warning Area late Wednesday night with the rain then coming to
an end sometime Thursday night. Due to extensive cloud cover and
rainfall...temperatures will remain below normal...in the middle 50s to
lower 60s.

Friday through Sunday...mild to warm Pacific air invades the Midwest
as the upper level flow becomes zonal and then southwest.
Temperatures will respond nicely with a fabulous Indian Summer
weekend expected with plenty of sunshine. Highs on Friday will be in
the 60s and then warming into at least the lower 70s most locations
over the weekend. Sunday could end up warmer than forecast as the
850 mb thermal ridge is located across the County Warning Area. As low pressure
organizes in the Central Plains this will tighten the gradient and
southerly winds should gust to over 30 to 35 miles per hour...which is needed
to pull the warmer air northward this time of year.

Early next week...low confidence as the European model (ecmwf) takes a cyclone from
the Central Plains into the northern Great Lakes region...with a strong
cold front sweeping across the County Warning Area. However...interesting that the
European model (ecmwf) has a dry frontal passage keeping the precipitation to our north tied to
the better dynamics or well to our south where the better moisture
will be located. On the other hand...the GFS develops showers and
thunderstorms along the cold front across the entire County Warning Area. For now we
will have chance probability of precipitation especially on Monday.

&&

Aviation...(for the 18z tafs through 18z Wednesday afternoon)
issued at 1231 PM CDT Tuesday Oct 21 2014

VFR conditions will be seen through 12z/22 as high pressure slowly
moves through the Midwest. There may or may not be a brief period
of MVFR right around sunrise Wednesday at kdbq/kmli. Weak flow
will again develop off Lake Michigan after 02z/22. Lake induced
clouds will again occur which might get into kdbq/kmli around
sunrise Wednesday.

&&

Dvn watches/warnings/advisories...
Iowa...none.
Illinois...none.
MO...none.
&&

$$

Synopsis...rp Kinney
short term...rp Kinney
long term...haase
aviation...08

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