Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 232343
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
643 PM CDT Thu Mar 23 2017

...00z AVIATION UPDATE...

.SYNOPSIS...
Issued at 325 PM CDT Thu Mar 23 2017

18Z surface data has a warm front from eastern Nebraska into far
western Kentucky.  Dew points were in the teens and 20s across the
Great Lakes with 30s from the northern Plains into the lower Ohio
Valley. Dew points of 40 and higher ran from the central Plains to
the Gulf Coast of Texas.

&&

.SHORT TERM...(This Evening through Friday)
ISSUED AT 325 PM CDT Thu Mar 23 2017

The 12z sounding tells the story. A large layer of dry air near the
surface which has keep most of the area dry. This dry layer has
moistened during the day allowing scattered showers and sprinkles to
develop. The forcing that developed the rain will continue moving
east northeast through sunset with the best chances of light rain in
the I-80 corridor up to highway 30 east of the Mississippi.

Two areas of forcing are moving across Iowa that have generated some
showers and thunderstorms. However, as this forcing moves further
away from the better moisture, the convection is slowly decaying.

RAP trends show an area of weak forcing developing in eastern Iowa
this evening and moving east northeast. This forcing may be just
enough to generate isolated showers or sprinkles during the evening
hours.

Late this evening and overnight mainly dry conditions are expected
as the front moves north of the area and the better forcing is
focused across the upper Midwest.

Temperatures will drop very little this evening before rising the
remainder of the night.

On Friday, mainly dry conditions are expected during the morning as
the better moisture and forcing remain west of the area. A possible
exception may be Buchanan, and parts of Delaware/Benton counties
that may see some light rain.

Friday afternoon moisture surges into the area as the storm system
approaches. Diurnal heating will allow showers and then
thunderstorms to develop from west to east during the afternoon
hours. The best chances for rain will be west of the Mississippi.
Temperatures should average well above normal.

.LONG TERM...(Friday Night through Thursday)
ISSUED AT 325 PM CDT Thu Mar 23 2017

Forecast focus on a very active storm pattern with the potential for
four separate storm systems impacting the Midwest over the next 10
days.  The storm track will extend from the Pacific Northwest to the
mid MS Valley bringing moderate to heavy rainfall amounts to the cwa.

Friday night and Saturday:  Strong storm system to lift out of the
southern Rockies and into MO. Strong forcing, combined with a nice
warm conveyor belt out of the Gulf, will bring widespread rain and a
few embedded thunderstorms to the cwa. PWAT`s increase to over an
inch with a back-door cold front feeding in from strong high
pressure north of the Great Lakes. This warm moist feed aloft over
the "lake-enhanced" cold dome should bring widespread rain amounts
of at least an inch, possibly 2 inches at some spots in steadier and
heavier rainfall. With minimal instability over the cwa, the threat
of strong/severe storms looks to be well to our south.

Will go with the cooler MET guidance vs the MAV, with the superblend
basically taking a "middle of the road" approach. However, being
that the ECMWF does better at depicting back-door cold fronts this
model has even colder temperatures, but haven`t gone quite that cold
yet, for later shifts to consider. As of now, the grids will have
lows Friday night in the lower 40s far north to the lower 50s far
south. Highs on Saturday should range from the mid 40s nw to around
60 se. However, these readings could be 3 to 6 degrees too warm.

Saturday night and Sunday: The occluding/filling system will
gradually move to southern Lower MI with any lingering showers
coming to an end. Highs will be in the 50s.

Sunday night through Monday night: The next potent wave currently
slamming into the Pacific Northwest will quickly dive into the
central Plains and into MO early next week. This should bring
another widespread rain event to the cwa.

Later next week into the following weekend:  Models suggest a couple
more strong storm systems taking a similar track. Both of these
systems may also bring widespread rainfall for late March/Early
April.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
ISSUED AT 631 PM CDT Thu Mar 23 2017

A warm front will lift north through the terminals tonight, and
there is a low chance of a shower at CID and DBQ ahead of the
front. Otherwise, generally vfr conditions expected with S/SE
winds around 10 kt and gusty at times. Have maintained low level
wind shear at all terminals by mid evening into early Friday
morning as winds increase to 40-50 kts in 1500-2000 ft agl layer.
Anticipate showers and storms to be on the increase across the
area mid to late Friday afternoon and especially Friday evening
ahead of an approaching cold front. Being late in the taf cycle
I have not made any mention, but will certainly be addressing for
06z tafs.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&

$$

SYNOPSIS...08
SHORT TERM...08
LONG TERM...Haase
AVIATION...McClure


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