Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 192043
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
343 PM CDT TUE JUL 19 2016

.SYNOPSIS...
Issued at 314 PM CDT Tue Jul 19 2016

Similar to the majority of convective events this summer, the sfc
theta-e and MLCAPE gradient is bisecting eastern Iowa and
northwestern Illinois. A severe complex of storms, with a history
of producing damaging winds and a few brief tornadoes, is
currently moving eastward out of south-central Iowa and north-
central Missouri. The greatest risk for severe weather late this
aftn and evening will be in the counties along and south of
highway 34.

&&

.SHORT TERM...(This Evening through Wednesday)
ISSUED AT 314 PM CDT Tue Jul 19 2016

This Afternoon into this Evening...Complex of light to moderate
stratiform rain shield with embedded convective elements to
gradually work its way to the ESE along the northern periphery of
the MLCAPE gradient, affecting roughly the southeast two-thirds
of the forecast area. The severe risk remains across the southern
portion of the CWA.

Severe storm potential: There is a slight risk for severe
thunderstorms along and southwest of a Marshalltown, Iowa to
Muscatine, Iowa to Macomb, Illinois line. Here instability will be
on the order of 2000-3000 J/kg MLCAPE (DCAPE over 1000 J/kg) and
0-6 km shear between 30-40 kts. Consequently, the environmental
ingredients are sufficient for a few strong or severe
thunderstorms. The strongest storms would be capable of producing
wind gusts over 60 mph, torrential rainfall rates given PWATs up
near 2 inches, and possibly an isolated brief tornado. Tropical-
like vertical moisture/temp profiles are not supportive of large
hail.

Timing: The dominant storm complex will move from west to east
through roughly the southern two tiers of counties through 6
or 7 PM.

Tonight into Wednesday...Nocturnal low-level jet forecast to veer
late tonight, increasing chances for elevated showers and storms,
probably well after midnight. This wave of convection will most
likely linger into Wednesday morning and even the aftn over at
least the eastern half of the CWA. Very heavy rainfall rates,
lightning strikes, and localized strong wind gusts are the
primary threats.

Aforementioned instability gradient is not expected to make
significant progress to the east, which keeps the chances for
showers and thunderstorms across majority of the of the forecast
area. The exception is over the far southwest where a Excessive
Heat Watch is now in effect Wednesday afternoon.

.LONG TERM...(Wednesday Night through Tuesday)
ISSUED AT 314 PM CDT Tue Jul 19 2016

Long term discussion will be sent out shortly...

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
ISSUED AT 1240 PM CDT Tue Jul 19 2016

Large area of stratiform rain and embedded convective elements to
manifest as increasing clouds and chances for -TSRA/TSRA through
the aftn into this evening. Highest probability for brief IFR/LIFR
ceilings and visibilities is at KBRL. Also potential for torrential
rainfall rates and gusty erratic winds at KBRL with thunderstorms
between approximately 21-23Z.

As the complex exits to the south this evening, conditions should
improve to VFR through tonight. Left out mention of storms
overnight due to low confidence on more than isolated coverage.
Uttech


&&

.DVN Watches/Warnings/Advisories...
IA...Excessive Heat Watch from Thursday morning through Saturday
     evening for Benton-Cedar-Clinton-Des Moines-Henry IA-Iowa-
     Jackson-Johnson-Jones-Linn-Louisa-Muscatine-Scott-
     Washington.

     Excessive Heat Watch from Wednesday afternoon through Saturday
     evening for Jefferson-Keokuk-Lee-Van Buren.

     Excessive Heat Watch from Thursday morning through Friday
     evening for Buchanan-Delaware-Dubuque.

IL...Excessive Heat Watch from Thursday morning through Saturday
     evening for Bureau-Carroll-Henderson-Henry IL-McDonough-
     Mercer-Putnam-Rock Island-Warren-Whiteside.

     Excessive Heat Watch from Wednesday afternoon through Saturday
     evening for Hancock.

     Excessive Heat Watch from Thursday morning through Friday
     evening for Jo Daviess-Stephenson.

MO...Excessive Heat Watch from Wednesday afternoon through Saturday
     evening for Clark-Scotland.

&&

$$

SYNOPSIS...Uttech
SHORT TERM...Uttech
LONG TERM...Uttech
AVIATION...Uttech


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