Severe Thunderstorm Warning 90, NWS Quad Cities, IA

Area Forecast Discussion
National Weather Service Quad Cities IA IL
813 PM CDT Thu Oct 6 2016

.UPDATE...
Issued at 755 PM CDT Thu Oct 6 2016

00z DVN raob shows pronounced low level inversion around 880 mb
capping surface based parcels. This would suggest any severe
wind threat is very low and would likely require a rotating storm
or fairly decent MESO to penetrate strong to severe wind to the
surface. While this can't be ruled out given such strong
environmental shear it would appear to be a low or isolated
risk. Hail may actually have a better chance of occurrence
per sounding with dry air aloft and WBZ around 10.8 kft agl, but
lapse rates while steep not overly impressive at around 6c/km
thus likely looking at sub-severe hail barring any rotating storm.
Toward midnight and through the overnight the capping inversion
will erode as the front moves in. This will allow for better
momentum transfer to surface, however instability will be weaker
by then and so while gusty winds would be likely with any storms
the threat for severe wind would be low. Storm motions will be
quite fast and seeing some at over 45 kts. This will limit rain
amounts to less than 0.5 inch in most areas, with portions of the
western and southern cwa most favored for the highest amounts, as
anticipate a weakening trend with the convection as it moves east.

&&

.SYNOPSIS...
Issued at 300 PM CDT Thu Oct 6 2016

Strong upper level located over western Nebraska lead to surface
cyclogenesis across Kansas this afternoon. This system is forecast
to move to the east and drag a warm front north across the area
through today. Cloud cover for most of the day has limited overall
heating and destabilization. This has limited the chance for
thunder this afternoon. Tonight, the surface low is forecast to
move through the area and lead to showers and thunderstorms across
the area.

&&

.SHORT TERM...(This Evening through Friday)
ISSUED AT 300 PM CDT Thu Oct 6 2016

Main forecast concern for the short term are the chances for
severe weather this evening and into tonight. The main forcing for
storms should be the cold front as it sweeps into the area. There
is a small chance that we could see some prefrontal convection,
but at this time confidence for that is low.

Guidance is in good agreement with track of the low pressure
after 00z Friday. The center of the low will stay just out of the
area as it moves to the NE through the period. The cold front will
usher in a much cooler and drier airmass for Tuesday with temps
below average and clear skies.

As far as the threat for severe weather for tonight. It appears
that the best threat for severe weather remains west of the
Mississippi River. With the timing of the fropa and thunderstorms
later in the day, after 00z and closer to 03z across the west.
Many of the storms will be in a decaying state. However, with the
shear across the area, there is a marginal potential for tornadoes
and wind gusts. Do not think that there is much of a risk for
large hail across the area. CAMS have been consistent with the
potential for storms remaining after 00z and more like 03z.

.LONG TERM...(Friday Night through Thursday)
ISSUED AT 300 PM CDT Thu Oct 6 2016

Overview: Dry weather and above average temperatures forecast into
Thursday, making for good harvesting conditions (although there is a
chance for rain by Thursday evening/night). With the mild temps, see
no threat for a freeze through next week.

Friday Night...High pressure builds in behind a cold front, ushering
in drier and cooler air. Clear and cool in the lower to mid 40s and
light winds. Favored low-lying cold spots may dip into the upper 30s.

Saturday and Sunday...Forecast highs are in the mid to upper 60s on
Saturday and then a few degrees warmer on Sunday. We'll have cool
overnight lows in the 40s which is normal for this time of year. A
very nice fall weekend to say the least.

Monday through Thursday...Warm in the mid 60s to lower 70s on
average with some day-to-day variation. Mid-level westerly winds
flowing perpendicular to the Northern Rockies progged to induce lee-
side cyclogenesis across the Northern Plains, thereby reinforcing
southerly winds and mild 850 temps above 10 C across the Midwest.
The low will move eastward with time, and could drag a cold front
with showers and thunderstorms through E Iowa/NW Illinois later on
Thursday/Thursday night. Uttech

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
ISSUED AT 633 PM CDT Thu Oct 6 2016

Have added mention of low level wind shear to the TAFs as
NAM/RAP/GFS BUFR soundings show winds increasing to around 50 kts
near 2kft agl by mid evening into the overnight ahead of a strong
cold front. The cold front will be accompanied by showers and
storms with brief periods of MVFR to IFR conditions in the storms.
The strongest storms will also be capable of producing strong
gusty winds of 30-45 kts. The cold front will sweep across the
terminals overnight and bring gusty northwest winds and likely a
period of lower clouds with mostly MVFR ceilings possibly
lingering until mid morning Friday. Expect a return to VFR
conditions by Friday afternoon with brisk northwest winds 15-25
kts.

&&

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

UPDATE...McClure
SYNOPSIS...Gibbs
SHORT TERM...Gibbs
LONG TERM...Uttech
AVIATION...McClure

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
820 PM CDT THU OCT 6 2016

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-070915-
BUCHANAN-DELAWARE-DUBUQUE-BENTON-LINN-JONES-JACKSON-IOWA-JOHNSON-
CEDAR-CLINTON-MUSCATINE-SCOTT-KEOKUK-WASHINGTON-LOUISA-JEFFERSON-
HENRY IA-DES MOINES-VAN BUREN-LEE-JO DAVIESS-STEPHENSON-CARROLL-
WHITESIDE-ROCK ISLAND-HENRY IL-BUREAU-PUTNAM-MERCER-HENDERSON-
WARREN-HANCOCK-MCDONOUGH-SCOTLAND-CLARK-
820 PM CDT THU OCT 6 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL
ILLINOIS...NORTHWEST ILLINOIS...WEST CENTRAL ILLINOIS...EAST
CENTRAL IOWA...NORTHEAST IOWA...SOUTHEAST IOWA AND NORTHEAST
MISSOURI.

.DAY ONE...TONIGHT

THUNDERSTORMS ARE LIKELY OVER PORTIONS OF THE OUTLOOK AREA TONIGHT.
A FEW OF STORMS MAY PRODUCE SMALL HAIL AND GUSTY WINDS...BUT THE
THREAT FOR SEVERE WEATHER APPEARS LOW.

THE WAPSIPINICON...IOWA...CEDAR AND MISSISSIPPI RIVERS ARE
EXPERIENCING FLOODING. PLEASE SEE THE LATEST FLOOD STATEMENTS AND
FLOOD WARNINGS FOR DETAILS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED TONIGHT.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE QUAD CITIES IA/IL
945 PM CDT THU OCT 6 2016

ILC131-161-IAC057-087-115-070315-
ROCK ISLAND-MERCER-HENRY-LOUISA-DES MOINES-
945 PM CDT THU OCT 6 2016

...A STRONG THUNDERSTORM WILL AFFECT SOUTHWESTERN ROCK ISLAND...
WESTERN MERCER...NORTHEASTERN HENRY...LOUISA AND NORTHERN DES MOINES
COUNTIES UNTIL 1015 PM CDT...

AT 944 PM CDT...A STRONG THUNDERSTORM WAS LOCATED OVER MOUNT UNION...
OR 10 MILES SOUTHWEST OF WAPELLO...MOVING NORTHEAST AT 50 MPH.

WINDS TO AROUND 50 MPH AND HALF INCH HAIL ARE LIKELY WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE...
MOUNT PLEASANT...WAPELLO...MEDIAPOLIS...WINFIELD...MORNING SUN...
MILLERSBURG...NEW BOSTON...KEITHSBURG...GRANDVIEW...ELIZA...JOY...
OLDS...SEATON...OAKVILLE...MOUNT UNION...MANNON...TOOLESBORO...
OGLE...KOSSUTH AND FLAMING PRAIRIE PARK.

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM.
LIGHTNING CAN STRIKE 10 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE
SHELTER INSIDE A BUILDING OR VEHICLE.

LAT...LON 4112 9163 4116 9152 4116 9149 4118 9149
      4140 9089 4111 9074 4107 9095 4106 9095
      4092 9153
TIME...MOT...LOC 0244Z 245DEG 42KT 4109 9136

MCCLURE