Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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332
FXUS63 KDVN 220532
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1232 AM CDT Tue Oct 22 2019

...06z AVIATION UPDATE...

.UPDATE...
Issued at 823 PM CDT Mon Oct 21 2019

With coordination with offices to the east and northeast, I am
expanding the wind advisory through our Illinois counties east of
the current product. This will run identically with the
previous placement through 3 PM Tuesday.

Otherwise, the light showers are already well handled by the low
pops in our forecast.

UPDATE Issued at 442 PM CDT Mon Oct 21 2019

Recent winds gusts on the leading edge of the cold advection over
eastern Iowa, are resulting in some wind gusts to 45 mph, thus I
have issued a quick update to start the wind advisory right now,
as opposed to midnight. There may be a period where winds
decrease a bit this evening, prior to shifting to the northwest
later this evening and increasing for the long haul.

ERVIN

&&

.SYNOPSIS...
Issued at 217 PM CDT Mon Oct 21 2019

This afternoon is quite a nice change (for the most part) from
our dreary, overcast, stormy morning. As of 2 PM, temperatures
ranged from 53 in Cedar Rapids, to 64 in Freeport under a mix of
sun and clouds. Low pressure was centered not too far away over
central Iowa, and was slowly moving northeast based on latest
surface analysis. A few wind gusts near 40 MPH were common along
and east of the Mississippi River, as a dry slot evident on WV
imagery worked over the area and allowed winds aloft to mix down
to the surface. Further west, wind gusts of 35-45 MPH were
occurring in central and eastern Nebraska, with some peak gusts of
55-60 MPH seen as well! This low pressure, and wind, will be our
primary concerns and challenges for the short term period.

&&

.SHORT TERM...(This Evening through Tuesday)
ISSUED AT 217 PM CDT Mon Oct 21 2019

Key Messages...

1) Strong winds expected across the area beginning this evening,
lasting through Tuesday morning.

2) Wrap-around rain showers tonight with light amounts expected.

Challenging forecast with differences primarily in the wind speeds
and gusts amongst guidance.

Surface low pressure will continue to slowly move north through the
day, with strengthening expected to continue as the 500 hPa low
deepens further with continued CVA across the region. With the
deepening, the pressure gradient is expected to tighten on the back
side of the low, leading to an increase of southwest to west winds
tonight.

Several CAMs including the HRRR and the RAP have remained consistent
with very windy conditions across the area for tonight. However,
they have also remained consistent with initializing around 5-10 kts
too high from current obs, which is likely having impacts on
forecast winds later in the period. However, global models and CAMs
are in agreement of winds around 925-850 hPa near 45-55 kts passing
across the area tonight and Tuesday morning. As clouds and moisture
build in behind the departing surface low, expecting the environment
to not decouple too much from the boundary layer, which will help
support some mixing of winds to the surface. BUFKIT sounding
profiles are also in agreement with this scenario.

After collaboration with surrounding offices, have decided to
issue a wind advisory for all of eastern Iowa and portions of
northwest Illinois. Potential exists for sustained winds of 25-30
MPH, with frequent gusts to 45 MPH at times late tonight and
Tuesday morning. In addition, there will be scattered rain showers
and pockets of drizzle as moisture interacts with lift in the
vort maxes wrapping around the upper level low, which may allow
additional mixing of winds. This may lead to brief periods of
higher gusts.

Winds will begin to decrease Tuesday afternoon as the low pressure
moves north of Lake Superior and the pressure gradient relaxes.
Surface ridging will approach from the west, keeping our weather
dry and quiet through the early portion of the long term period.

.LONG TERM...(Tuesday Night through Monday)
ISSUED AT 217 PM CDT Mon Oct 21 2019

Overall, relatively dry weather is expected through next weekend,
with continued below normal temperatures.

Tuesday night, winds will continue to diminish as the area is
between systems; with the low moving even further off to the NE and
the next quick moving clipper system approaching from the NW.

Wednesday into Thursday, the clipper-type system will sweep across
the area bringing locations along and north of I-80 mainly a slight
chance for some showers. The best chance at measurable rain; 30
pops; is along Highway 20 from Independence to Manchester.

Thursday, models have shifted a system SE, taking it up the OH
Valley region. It does still clip our east and southeast counties
with some low/20-30 chance pops. Dry conditions will prevail
elsewhere.

Thursday night into Friday, skies will be clearing out from NW to SE
with nearly calm winds. Lows in the upper 20s and low 30s look to be
on track; with the coldest values over the NW half of the CWA.

High pressure will keep things quiet Friday and Saturday with
continued below normal temps.

Some moderation in temperatures is expected Sunday into next Monday,
as a low in Manitoba brings a cold front SE into the region. In the
same timeframe, some models show a southern system lifting into the
mid Mississippi Valley region. For now, there is a slight chance for
rain in the forecast for Saturday night through the first half of
Sunday. Needless to say, confidence is low at this time.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday Night)
ISSUED AT 1225 AM CDT Tue Oct 22 2019

Main concern is the strong westerly winds as deep low pressure
near Minneapolis tracks slowly toward Lake Superior. The
attendant tight pressure gradient, and mixing aided by cold
advection will fuel westerly winds sustained at times between
20 and 30 kts, and gusting over 40 kts today. Wrap-around low
clouds with lower VFR to MVFR ceilings will persist through much
of the morning, before clearing gradually overspreads the area
from southwest to northeast this afternoon and evening, clearing
first at BRL and lastly at DBQ. Bouts of very light rain and
drizzle will accompany the lower clouds overnight into Tuesday
morning. The winds may gradually lose the gustiness tonight, with
the clearing and stabilizing boundary layer but likely will remain
sustained above 10 kts.

&&

.HYDROLOGY...
Issued at 1225 PM CDT Mon Oct 21 2019

River levels continue to recede today. Rainfall amounts were
generally under a half inch with just two reports near an inch.
Relatively dry conditions are anticipated over the next week.

The Pecatonica at Freeport fell out of flood this morning and is
expected to hold steady through Friday just under flood stage. On
the Rock River, Moline will fall below flood stage this
afternoon, while Joslin will continue to slowly fall. Routed flow
on the Mississippi River may push the Dubuque railroad gage to
near flood stage late this week. South of the Quad Cities, levels
will continue to recede for the next 2 to 3 days, before leveling
off and possibly rising slightly late this week and into next
week.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Wind Advisory until 3 PM CDT this afternoon for Benton-Buchanan-
     Cedar-Clinton-Delaware-Des Moines-Dubuque-Henry IA-Iowa-
     Jackson-Jefferson-Johnson-Jones-Keokuk-Lee-Linn-Louisa-
     Muscatine-Scott-Van Buren-Washington.

IL...Wind Advisory until 3 PM CDT this afternoon for Bureau-Carroll-
     Henderson-Henry IL-Jo Daviess-Mercer-Putnam-Rock Island-
     Stephenson-Whiteside.

MO...NONE.
&&

$$

UPDATE...Ervin
SYNOPSIS...Speck
SHORT TERM...Speck
LONG TERM...14
AVIATION...McClure
HYDROLOGY...14



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