Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 262055
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
355 PM CDT THU MAY 26 2016

.SYNOPSIS...
Issued at 330 PM CDT Thu May 26 2016

The latest SFC analysis was indicating low pressure with an arching
warm front acrs KS into Southeastern Neb back down into central MO.
A secondary trof was noted up into southwestern IA. A vort max was
noted acrs southeastern CO, with lee side southwesterly steering
flow sprawling out acrs the east central Plains.

&&

.SHORT TERM...(THIS EVENING THROUGH Friday)
ISSUED AT 330 PM CDT Thu May 26 2016

tonight...will have to have some POPs this evening in the west
central to southwestern CWA for the potential for some of the
showers and storms in the current convectively active zone acrs
northwestern MO/IA border region, to propagate into the local FCST
area...probably into the southwestern and southern third of the
local area. But this activity will have to battle lingering mid and
upper ridge bulge from acrs southeastern IL...up acrs the upper MS
RVR Valley and thus may get eaten away at or decay some as it tries
to push east late this afternoon and into mid evening.

But later on tonight, the upper wave currently acrs the southwestern
plains will roll up in steepening southwest flow acrs southwest into
central IA by midnight. This should help whatever congeals(MCS) out
of the current activity to the west/southwest...make it acrs the
local area. It may also spark new development in central Iowa bid
mid to late evening, which could also then come acrs the area as a
MCS-type feature. MCS forcing tools from the favored 12z run UKMET
and ECMWF target the northwest to northern half of the FCST area
from midnight on into early Friday morning. Other solutions hit the
south half of the CWA again. Although do think the UKMET/Euro are
hitting the right areas(northwest half or north half along and north
of I80)...not sure if there will not be convection in the south as
well and will go blanket Likely POPs after midnight into Friday
morning. With CAPES of 1500 to over 2000 J/KG lingering well into
the overnight, again see the threat of a storm cluster developing
it`s own cold pool and being able to produce damaging winds. Large
hail a secondary threat with marginal deep layer shear to support
bigger stones, but still not out of the question. With PWATs
increasing to 1.5 or even up to 1.7 inches, locally heavy rain also
a good bet with any enhanced storm cluster. A few swaths of 1-2
inches of rainfall possible by Fri morning, but most areas from 0.50
to around an inch. Ponding of water on roads/drainage ditches
possible.

Friday...convective system or clusters may still be ongoing through
mid morning, before the wave lifts north. Could have some strong
storms ongoing as well at this time around and a few hours after
sunrise despite the less then optimum time of day. Activity may then
wane into the afternoon and FCST POPs a bit high, but ongoing
southerly flow and moisture convergence may fester new development
as the afternoon progresses. High temps a challenge depending on
extent of convective debris and will do the middle of the road upper
70s to lower 80s.    ..12..


.LONG TERM...(Friday NIGHT THROUGH next Thursday)
ISSUED AT 330 PM CDT Thu May 26 2016

Active weather pattern of almost daily showers & storms the next 7
days with slightly above normal temperatures.

Long term forecast confidence assessment...slightly below average or
fair to poor with timing, coverage and intensity of precipitation
events the main issue.  American models are too moist which impacts
timing and evolution of convective events and propagation.  The most
significant impacts are subsequent events after tonight will be
very suspect.

Overview...Initialization and verification are fair with most
solutions underplaying evolution of developing complex in the
central plains.  Hi-res ECMWF slightly better suggesting a 70/30 mix
with GFS and importance of poor QPF reflection of evolution of
convective systems days 2-7.  Widespread 1 to 4+ rain amounts
expected which may result in water issues by the end of the forecast
period. Precipitable water of 1.5+ over most of the period will
ensure locally heavy rain totals will be an issue.

Friday Night...Local tools support a decent MCS event over at least
NW parts and possibly all CWA with widespread .5 to 1.5+ inches of
rain with some isolated severe of mainly bowing segments of winds to
around 60 MPH.  POPS in the likely category and lows mostly in the
middle 60s.

Saturday...lingering showers and storms with deep and fast south jet
ahead of rotating upper low in south plains moving into the upper
midwest.  Some risk of training of storms for locally higher rain
amounts of 2+ inches possible.  Highs should be mostly around 80
degrees with PM MUCAPES of 1000 to 1500 J/KG for marginal severe
risk in mostly in PM hours.

Saturday night into Sunday...Upper low to rotate northeast across
the region for a probable another convective event.  Timing most
likely for last convective event probably Saturday night with
possibly enough shear and instability for locally severe storms for
later shifts to consider as well as locally heavy rains.  Lows in
the lower 60s with highs mostly in the lower 80s.

Monday and Monday night...mostly dry with a chance of scattered
showers and storms with weak high pressure in southwesterly upper
level flow and slightly drier dewpoints.  Highs in the lower 80s
with mins in the lower 60s and possibly upper 50s.

Tuesday and Wednesday...Next upper level disturbance to impact the
region with poor confidence on timing and location of best forcing.
Large scale regime favorable for decent rains and isolated severe
once again.  Additional rain totals of 1 to locally 2 plus inches
seem reasonable which if get expected widespread rains the next 72+
hours of 1 to 2+ inches should cause water issue on some area
rivers.

Thursday and Friday...Poor confidence with best estimate of weak
high pressure moving in with little or no chance of precipitation.
Highs should be per local thermal tools mostly in the upper 70s to
around 80 or near normal for late May.  Mins mid 50s to around 60
suggested.    Nichols

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z Friday AFTERNOON)
ISSUED AT 1247 PM CDT Thu May 26 2016

A VFR afternoon with thickening high clouds from storms off to the
southwest...south to southwest winds of 6-10 KTS. Then eyes turn
to the storm clusters ongoing in northwestern MO and if some of
them can get into the VCNTY of the BRL TAF toward sunset this
evening. Mys just be decaying remnants initially, but chances are
more thunderstorms developing out west and southwest will come
acrs many of the TAF sites tonight, with heavy rain and possibly
gusty winds. Timing and how far north or south they occur at lower
confidence levels at this point and will place VCNTY and PROB30`s
of thunderstorms and associated MVFR to IFR conditions at
MLI/CID/DBQ for periods of tonight. Will go predominant at BRL
from mid evening and into the overnight as the south may be more
favorable for widespread storm system coverage.   ..12..

&&

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

$$

SYNOPSIS...12
SHORT TERM...12
LONG TERM...Nichols
AVIATION...12



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