Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 241132 AAA
AFDDVN

Area Forecast Discussion...UPDATED
National Weather Service Quad Cities IA IL
632 AM CDT Mon Apr 24 2017

...AVIATION UPDATE...

.SYNOPSIS...
Issued at 332 AM CDT Mon Apr 24 2017

Warmer temperatures than yesterday morning were across the area
this morning. High pressure that had been the hallmark of the
weekend was moving out of the area this morning. Southwesterly
winds were starting to take hold across the area as the next upper
level wave moves towards the area today.

&&

.SHORT TERM...(Today and Tonight)
ISSUED AT 332 AM CDT Mon Apr 24 2017

High pressure will still rein supreme today before upper level
clouds move into the area tonight. Main forecast concern are the
temperatures and dewpoints for today. Otherwise short term period
should be quiet before the period of unsettled weather moves into
the area.

Guidance seems to be underdone on temperatures for today and
overdone on dewpoints. Lowered dewpoints much lower than guidance
this afternoon. This will lead to lower RH as well. As far as
temperatures, the gridded models along with the hires cams are
again higher than the deterministic synoptic models. Have trended
temperatures towards the warmer solutions. Overall today will be
almost a repeat of yesterday except for there being wind.

.LONG TERM...(Tuesday through Sunday)
ISSUED AT 332 AM CDT Mon Apr 24 2017

Changes continue with two precipitation events and lots of clouds
next 7 days with potential significant rainfall.

Long Term Forecast Confidence Assessment...generally poor or below
average due to continued major changes in timing and coverage of
precipitation events which are still developing.  Trends continue of
two distinct events, one Tuesday through Wednesday and next event
this weekend.  Poor continuity continues on timing, coverage,
amounts of mostly showers vs some storms.  This likely to impact
temps by 5+ degree as evidenced by high/low temp changes from last
night and probably to continue next day or so.  Large SW regime
upper level flow supports areas of 1 to 2+ inches of rain to fall by
late Sunday.

Tuesday & Tuesday night...Trend continues for a slower frontal
system with low POPS northwest of light showers. Moderate S/SE winds
and some sunshine suggest highs 70s near 80 readings possible SE
sections. Tuesday night...POPS a challenge as slower system with a
lowering most locations of mostly lighter amounts.  Mins temps minor
changes of mostly mid/upper 50s with near 50F far NW sections.

Wednesday & Wednesday night...Challenge for high temps with lots of
clouds and areas of showers and some storms suggested as surface
low tracks across the region with just embedded storms with limited
instability of CAPE AOB 850 J/KG. Strength of low still uncertain so
with .25 to locally near 1 inch mostly likely suggested attm. Highs
should see a large gradient with a 5+ degree error very possible
where front and precipitation occurs.  Currently a gradient of highs
mid 50s northwest to near 70F far SE sections. Wednesday
night...brisk northwest winds of 10 to 20+ mph to bring in colder
air.  Concern continues that clouds & BL mixing supports lows about
3 degrees higher of current mostly upper 30s to lower 40s for later
shifts to review. Strength and track of low due to changes and large
variance in solutions may change as well as impacting area lows and
when rains end.

Thursday and Thursday night...southwest flow aloft supports partly
to mostly cloudy skies with colder air and have trimmed highs
northwest a few degrees with lower 50s NW to upper 50s SE and likely
dry with light west to northwest winds. Thursday night...clouds may
keep mins a few degrees higher than current forecast of upper 30s
north to mid 40s south.

Friday through Sunday...once again a low confidence forecast on
timing and track of system.  Trends and regime flow all support a
large and slow moving system of showers initially and then scattered
likely non-severe storms late as surface approaches and passes.
Highs and lows again easily could be off again by 5+ degrees with
best estimate of mostly 55 to 65 degrees Friday/Saturday for highs
and lows 45 to 55F. Sunday depending on track could be warmer with
low 60s to low 70s and lows Sunday night with cooler air in the 40s.
Local techniques suggest widespread moderate to lower end heavy rain
amounts supported of .5 to 1.5+ inches.  This system once again low
confidence due to ongoing changes and likely to take another 24 to
36 hours to be more confidence on specifics.

Monday...strong low to be northeast with wraparound moisture
supports low POPS and colder temperatures with cold highs in the 50s
and mins Monday upper 30s or colder north into the low/mid 40s
south.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday Morning)
ISSUED AT 632 AM CDT Mon Apr 24 2017

VFR conditions through the period with the main aviation concern
being gusty winds this afternoon. There is also a chance for LLWS
after 00z tonight. However, confidence is low in this occurring,
so decided to leave out at this time.

&&

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

$$

SYNOPSIS...Gibbs
SHORT TERM...Gibbs
LONG TERM...Nichols
AVIATION...Gibbs



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