Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 220758
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
258 AM CDT Sat Apr 22 2017

...HYDROLOGY UPDATE...

.SYNOPSIS...
Issued at 258 AM CDT Sat Apr 22 2017

Early this morning, rain associated with a low pressure center was
located just south of the area. Even though the radar has shown
some returns across the far south, dry air has kept the rain from
making it to the ground. Closer to the area, high clouds were
keeping temperatures warmer than yesterday morning. High pressure
continues to move into the area from the northeast. This high
pressure will be the driver of today`s weather.

&&

.SHORT TERM...(Today and Tonight)
ISSUED AT 258 AM CDT Sat Apr 22 2017

Main forecast concern for the short term are the clouds and how
long will they last across the area. This will affect high
temperature forecasts for today.

With a vort max south of the CWA, weak H5 ridging attempts to move
into the area this morning. Clouds associated with the vort max
and convection will begin to exit the area today. Most guidance
seems to be too quick with the clouds leaving the area, so have
kept clouds in longer. Think that by mid afternoon most of the
area will be cloud free with the exception of high level strands
of cirrus. This will of course affect the temperatures for today.
The MOS guidance was on yesterday with the overall highs being
cooler yesterday. This mornings guidance has flipped with the MOS
being higher. Think that is overdone and that temps likely be on
the cooler end of guidance. If, more sun occurs, then temps will
likely need to be raised.

.LONG TERM...(Sunday through Friday)
ISSUED AT 258 AM CDT Sat Apr 22 2017

Trending toward slightly above normal temperatures with rounds of
of showers and scattered storms mid to late next week.

Long Term Forecast Confidence Assessment...Fair or average with
timing, coverage and amounts of precipitation with apparent marginal
severe weather risk the main forecast issue late next week.
Otherwise, next few days area highs and lows into Tuesday should
continue to tend toward slightly higher highs and slightly lower
lows. Area highs and lows days 4-7 due to cloud coverage and
precipitation may easily be off by 5+ degrees with timing, coverage
and uncertainty of these factors.

Sunday and Monday...Very minor changes.  Fair and mild with slightly
above normal temperatures.  Light winds Sunday becoming southerly on
Monday. Highs upper 60s to mid 70s with temps warmer Monday by 3 to
5 degrees most areas. Mins still on track for mostly lower 40s
Sunday AM and lower 50s Monday AM.

Tuesday...A weak front on track to pass through with low confidence
on amount of forcing or moisture with system.  Little change to
highs mid/upper 60s across far northwest to 70 to 75 south 1/2 to
2/3 behind boundary and clouds/precipitation.  Still have 20 to 40
POPS of showers with isolated storms with limited instability and
moisture resulting in CAPE values AOB 1000 J/KG or just a few brief
non-severe storms. Lows Tuesday night, keeping mid/upper 40s north
to lower 50s south.

Wednesday...weak high pressure to bring in a bit cooler air with
highs in the 60s and lows in the lower to middle 40s.  Have some
very low Pops which may be removed later if confidence of high
pressure increases and sky cover is lower due to more subsidence.

Thursday and Friday...Have increased POPS with stalled boundary and
next system to provide focus for showers and storms with high chance
to likely POPS due to boundary near or across the region with
location still low confidence.  Current trend is uncertain but
portions north of warm front to see clouds with easterly winds highs
mostly in the 60s in area of showers to possibly lower 70s south
sections with better chance for storms.  Instability may reach above
1000 J/KG south of the warm front.  Trends are suggesting mostly
moderate rain totals of .5 to .75 inches with locally 1-1.5+ inches
possible in storms.  This should have minor or no impacts to area
river levels.  Instability levels currently suggest marginal risk
for severe weather which will be better known next couple which of
days. Lows in the mid 40s north to the mid 50s south.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday Night)
ISSUED AT 1125 PM CDT Fri Apr 21 2017

High clouds will be common across the area through the TAF period
with VFR conditions.


&&

.HYDROLOGY...
Issued at 258 AM CDT Sat Apr 22 2017

Trend confirmed from past 24 hours is for lowering water levels on
all tributaries with dry conditions next three plus days to below
bankfull all areas next 12 to 24 hours.  Lower water levels
confirmed on portions of the Mississippi River south of Quad Cities
still forecast to stay in minor flooding next 5+ days but forecast
water levels are a few inches lower than last night and broad
forecast crests may drop a few more inches by mid week due to dry
conditions.  Both Gladstone and Burlington likely to just barely at
or possibly below minor flood as approach middle of next with next
system.

A mentioned in text for late next week, with climatological water
levels and drying ground and our lowering river levels falling
faster than forecast, these factors increasingly suggest significant
area basin rain totals over 1 inch would be needed to support an
increased threat of any renewed river flooding.  Again this risk, if
any, should be better known in next couple of days.

&&

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

$$

SYNOPSIS...Gibbs
SHORT TERM...Gibbs
LONG TERM...Nichols
AVIATION...RP Kinney
HYDROLOGY...Nichols


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