Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 221740
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1240 PM CDT WED JUN 22 2016

...AVIATION UPDATE...

.SYNOPSIS...
Issued at 355 AM CDT Wed Jun 22 2016

Warm front was arced across the SW half of the forecast area with
a heavy rain, and occasionally severe, MCS on-going early this
morning from N central IA across SE IA into north central IL.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CDT Wed Jun 22 2016

Very busy this morning with multiple challenges in the short
term. Discussion is thus concise and centered on the hazards today
and tonight.

Flash Flooding: Will continue the flash flood watch over the
northern half of the forecast until its current expiration time
of 15z. The current MCS, already producing very heavy rainfall and
likely flash flooding over portions of eastern IA, and its
nocturnal low level jet feed of high thetae should dissipate and
transition out of the area this morning, diminishing the threat of
training storms and excessive rainfall. Additional storms today
will have heavy rainfall rates, but will likely be more
progressive in a severe mode.

Severe weather: In the near term, the greatest severe potential
in the next few hours will be severe winds with the bowing storms
in SE IA into W central IL and then will have to watch closely the
storm at the back NW end of the line which will move into east
central IA in the CID and IOW for another round of possible very
heavy rain and possible damaging winds 6 to 7 am. Later today, SPC
has extended the moderate risk are further NW into NE IL and a
small part of far eastern IA near DBQ, while the enhanced area
remains over all but the far south. Somewhat concerned that the
warm front may remain further south and SW than models depict and
the critical triple point with the area of low pressure advancing
SE out of SD will move through east central IA or possibly SE IA
into west central IL this afternoon. Instability, shear and low
level wind profiles will favor supercells along and north of the
warm front and especially ahead of the surface low this afternoon,
with the complex evolving into a more linear severe complex
further east in the late afternoon.

Heat: Temperatures are likely to warm well into the 90s in the
warm sector of SE IA and W central IL this afternoon. With
dewpoints in the 70s, heat index values are likely to reach 100 to
possibly 105 and have thus issued a heat advisory for SE IA, NE MO
and W central IL from around noon to 7 pm.

.LONG TERM...(Thursday THROUGH Tuesday)
ISSUED AT 355 AM CDT Wed Jun 22 2016

Quieter weather and temperatures closer to mid June normals
follows for late week, then heat and humidity returns for the
weekend along with thunderstorm chances as another frontal system
rolls through the area. Low pops and continued above normal
temperatures follow for early next week.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z Thursday AFTERNOON)
ISSUED AT 1237 PM CDT Wed Jun 22 2016

VFR conditions with isolated to scattered convection was across
eastern Iowa and northern Illinois. VFR conditions will continue
through 06z/23 outside of any convection. MVFR/IFR conditions is likely
in any TSRA that develops through 02z/23. After 06z/23 light winds
are expected to allow fog to develop with MVFR conditions through
sunrise Thursday. After sunrise Thursday, conditions will slowly
improve to VFR.

&&

.HYDROLOGY...
Issued at 1043 AM CDT Wed Jun 22 2016

A good swath of heavy rain fell across the CWA overnight generally
in the Cedar and Iowa River basins. These rivers have been rising
across the entire basin, however there is considerable uncertainty
still to how much runoff there will be into the main channels and
then with the expected flows further downstream after the Cedar
enters the Iowa. Many of the small tributaries into these rivers
have crested so as this water gets into the main channels and the
flows are measured, confidence will increase in how high the river
will get in the lower part of the Iowa River. Forecasts currently
bring the river to over over flood stage from Columbus Junction
through the entry into the Mississippi, but have decided to hold
off on issuing flood warnings for these areas until there is a
better handle on the amount of water being routed down from
upstream.

&&

.DVN Watches/Warnings/Advisories...
IA...Heat Advisory until 7 PM CDT this evening for Des Moines-Henry
     IA-Jefferson-Lee-Van Buren.

IL...Heat Advisory until 7 PM CDT this evening for Hancock-Henderson-
     McDonough-Warren.

MO...Heat Advisory until 7 PM CDT this evening for Clark-Scotland.

&&

$$

SYNOPSIS...Sheets
SHORT TERM...Sheets
LONG TERM...Sheets
AVIATION...08
HYDROLOGY...Brooks



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