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fxus63 kdvn 190404 

Area forecast discussion
National Weather Service Quad Cities Iowa Illinois
1104 PM CDT sun Aug 18 2019

..aviation update...

issued at 310 PM CDT sun Aug 18 2019

18z surface data had the cold front from klse to koma with a pre-
frontal trof from northeast Illinois back through kotm. Dew points
were in the 70s from Ohio Valley into the Southern Plains and deep
south. Behind the front dew points were in the 50s and 60s.


Short term...(this evening through monday)
issued at 310 PM CDT sun Aug 18 2019

Cloud cover has resulted in a slow recovery of the atmosphere today.
Satellite trends show very weak diurnal cumulus clouds developing
along the front in central Iowa. So the question is will any diurnal
convection develop along the front late this afternoon and overnight.

Rap has shown convergence in the frontal zone as it moves into the
area late this afternoon and evening with unstable air aloft.
However the trends with the convergence has been to slowly weaken
with each New Run.

If convection develops late this afternoon it would be confined to
the immediate frontal zone and likely isolated in nature. There may
be a small area where areal coverage becomes scattered.

Thus will go with isolated showers and storms developing late this
afternoon and persisting through the evening as the front moves
through the area. After midnight any convection that develops will
slowly dissipate through sunrise.

On Monday there may or may not be a few lingering showers in the far
southeast and east areas around sunrise. If there are showers they
will end by mid-morning. The rest of the day will be warm and humid
as skies slowly clear. Heat index readings of 90 to 95 are possible
south of an Ottumwa, Iowa to Galesburg, Illinois line.

Long term...(monday night through sunday)
issued at 310 PM CDT sun Aug 18 2019

Models are in good overall agreement through the long term period.
The main forecast concerns are temperatures on Tuesday and chances
of precipitation through the period.

The long term period opens with northwesterly flow aloft as closed
area of high pressure expands eastward across Texas and Oklahoma and
into western Missouri and Arkansas. Tuesday looks to be the warmest
day of the period ahead of a cold front that will move across the
region Tuesday afternoon and evening. This will bring the chance of
showers and thunderstorms area during peak heating. There is a
marginal risk of severe thunderstorms across the area on Tuesday.
The timing of the front and potential precipitation calls into
question how warm we could get during the day. Current highs are in
the mid to upper 80s with dewpoints in the lower to mid 70s could
produce heat indices of 100 to 104 for 3 or 4 hours so there is also
the potential for a heat advisory but that will depend on the timing
of precipitation.

After Tuesday night, a strong upper level low will dig southward out
of eastern Canada and into the northeastern US. This will continue
to bring pieces of shortwave energy across the area every 18 to 24
hours with daily chances of showers and thunderstorms. There will
be dry periods in the forecast as ridging will follow in the wake of
these shortwave troughs but timing individual features this far in
advance is very difficult. Temperatures will be near normal on
Wednesday but then run slightly below normal Thursday into next


Aviation...(for the 06z tafs through 06z Monday night)
issued at 1102 PM CDT sun Aug 18 2019

Light northeast winds may allow for some fog and MVFR cigs/vis
late tonight into Monday morning, then followed by VFR conds for
most of the day on Monday. North to northeast winds less than 10


Dvn watches/warnings/advisories...


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