Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 270754
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
254 AM CDT FRI MAY 27 2016

.SYNOPSIS...
Issued at 253 AM CDT Fri May 27 2016

06Z sfc data has a collapsing meso high from central Iowa into
northern Missouri. The main frontal boundary ran from southern
Kansas into central Missouri with a squall line across eastern
Kansas. Dew points were were in the 60s from the Great Lakes and
Ohio Valley to the Gulf coast. Dew points in the 40s and 50s were
across the central and northern Plains.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 253 AM CDT Fri May 27 2016

Through sunrise a band of showers with embedded thunderstorms will
move north through the area. This precipitation is a result of
forcing created by the thunderstorm complex across Missouri last
evening.

For Friday, boundaries left over from the overnight convection will
provide the focus for new convection to develop during the day. Thus
isolated to scattered showers and thunderstorms should be seen
through sunset. The possibility does exist that convection may be at
a minimum during the morning hours with most of the area being dry.

Tonight, stronger forcing will move through the area. Isolated to
scattered convection during the evening will become more widespread
during the late evening and overnight hours.

.LONG TERM...(Saturday THROUGH Thursday)
ISSUED AT 253 AM CDT Fri May 27 2016

Convective chances will continue in our forecast for Saturday and
Saturday night as the main upper system passes through the region.
This does not mean widespread rainfall is a guarantee. Models offer
a variety of convective mode transitions of scattered strong storms,
to a swing a miss of a linear mode system to the west.  In the end,
it`s only worth 40 to 60 percent pops during the period for Sat/Sat
night, and QPF will be forecast conservatively with locations
generally under 1/2 inch. That said, the pwat values are certainly
supportive of localized heavy rain from storms over 1 inch, but out
river "basin average" QPF will not resolve this possibility until in
the short term.

Sunday, the dry slot will be sweeping through early in the day, and
I have reduced pops to slight chance in the morning, and a dry and
warm afternoon is expected. Dry weather should last through Sunday
night before showers and thunderstorm chances return for Memorial
Day through Thursday. The 00z model consensus suggests the best rain
threats during that period will be Monday night, and Tuesday. In
other periods, there is great differences in the position of the
upper trof locations, with the GEM and GFS slowest, and the EC the
fastest. Given how slowly the upper trof has been to move from the
southwest this past week, I think the GEM/GFS should be favored
here, especially since convective contamination does not seem to be
a factor in the synoptic trof speed.  Never the less, the divergent
model solutions result in much lower pops for Wednesday and
Thursday.

Temperatures in the lower 80s for highs and upper 50s to mid 60s for
lows will last through mid week, before a slight cool down for
Thursday and Friday.

Like earlier forecasts have noted this week, the most difficult task
in this intermittent convective pattern may be to show that dry
weather is as likely as rain on many days. That is a challenge for
all communicating this forecast.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z Friday NIGHT)
ISSUED AT 1153 PM CDT Thu May 26 2016

The potential for showers and thunderstorms throughout will
continue to be a challenge in the terminal forecasts. In the near
term, another round of rain with embedded thunderstorms will
spread north through the terminals overnight. Outside of the
stronger thunderstorms, conditions will remain vfr. Friday, it
looks like there will likely be a break in the precipitation from
mid morning through mid afternoon before another upper level wave
may trigger showers and thunderstorms late afternoon through
early evening. For now, this is presented with vicinity and
prob30 groups, which will likely be hit harder as forecast
confidence increases. The potential for thunderstorms could well
extend beyond the current 03z ending time mentioned at CID, DBQ
and MLI.


&&

.DVN Watches/Warnings/Advisories...
IA...None.
IL...None.
MO...None.
&&

$$

SYNOPSIS...08
SHORT TERM...08
LONG TERM...Ervin
AVIATION...Sheets



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