119
FXUS63 KDVN 061913
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
213 PM CDT Sat Jun 6 2026

.KEY MESSAGES...

- There is a marginal, level 1 out of 5, risk of isolated severe storms
  along and south of I-80 late this afternoon and evening.

- Rounds of nocturnal and diurnal convection through Monday
  night will bring a risk of locally heavy rainfall due to weak
  winds aloft. If storms stall, excessive rainfall is possible.

- Heat and humidity will increase around the middle of next week
  with temperatures in the 90s and heat indices pushing 100 or
  higher. The probability of heat headlines for part of next
  week is currently 30 to 40 percent.

&&

.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 212 PM CDT Sat Jun 6 2026

The diffuse frontal zone remains over the same axis as yesterday,
with southeast NE to northeast IL the placement of the main front,
but additional convective outflow boundaries found to the south,
with the main one found in northern Missouri this afternoon. This
diffuse wind field is keeping confidence low on the placement
of afternoon storm development, but in general, we prefer this
southern boundary to be most at risk for afternoon storms today,
and that is currently outlined by SPC`s marginal risk area. The
one thing we have today in abundance is CAPE. The warm and
humid air mass is currently shown to have 2000 to 3500 surface
based CAPE on SPC mesoanalysis page, with mixed layer CAPE of
1-2K. This unstable air, combined with weak flow in the mid
levels and poor lapse rates should allow for pulse typed
convection this afternoon and evening, with initially isolated
coverage, possibly upticking to higher end scattered/likely
coverage before waning again by mid evening. Another increase is
possible towards late evening and overnight as the LLJ begins
to impinge into the area, again resulting in a loosely
organized zone of showers and storms. While an isolated severe
storm is possible, the main threat will be localized torrential
rainfall, that could reach 2+" / in one hour at peak intensity.
Many locations, like last night, will certainly remain dry
tonight.

Sunday morning through Monday, this chaotic pattern will slowly
begin to be influenced by a broad upper low lifting northward from
the southern Plains. This will lead to an extended period of pops
and rain/thunder potential, with a high PWAT air mass in play. While
QPF placement is uncertain, as is timing of any period but this is a
wet pattern in general, with frequent chances for rainfall that
could be heavy at times.  PWAT values 1.5 to over 2 inches remain
forecast by most models through this period.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
Issued at 212 PM CDT Sat Jun 6 2026

Tuesday through Thursday, south to south flow returns the area, with
very warm air aloft, resulting in hot and humid, but rather windy at
times weather.  The edge of the heat dome will be where the
organized storm complexes are found. Right now the signal for the
organized storm complexes is in the northern Plains. However, the
models have a growing signal for organized storm development across
Iowa Wednesday afternoon that could move into eastern Iowa Wednesday
night. This signal will need to be watched to see if it remains
consistent into early next week. Pops have now increased to 40 to
70% for Wednesday night. This late week system will have much strong
winds aloft, and organized severe weather is more possible in that
regime.  SPC has begun outlining that system with slight risks areas
in Days 4-5 earlier today. Regarding heat, heat indices on
Tuesday generally look to be 95 to 100. Heat indices exceeding
100 have a 50 percent probability of occurring Wednesday and
Thursday. Currently there is a 30-40 percent probability of heat
headlines being needed in the Wednesday/Thursday time frame.&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1216 PM CDT Sat Jun 6 2026

Quiet VFR hours will begin the forecast period today, as light
winds and partly cloudy skies with bases over 3kft will continue
through the afternoon hours. A few isolated thunderstorms may
fire in the heat of the afternoon, and if they form they will
move slowly, and produce a period of torrential rainfall, gusty
winds and small hail. This coverage is limited and unfocused, so
I have not placed into any TAF except for a prob30 at
Burlington. Otherwise late this evening and overnight, a band of
showers ands storms could form over the entire area, and lift
northeast by sunrise Sunday. This is not certain, and handled
with Pro30 groups at all sites except for DBQ. Some MVFR cigs
are expected overnight at times with storms and possibly more
consistently at DBQ where a temporary conditions of BKN025 is
included for stratocumulus formation late tonight.

Sunday morning through afternoon, additional showers and storms
may be forming in the area, but these are not yet included in
the TAF.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...None.
MO...None.

&&

$$

SHORT TERM...Ervin
LONG TERM...Ervin/08
AVIATION...Ervin