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000
FXUS63 KDMX 301209
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
709 AM CDT MON MAY 30 2016

...Updated Aviation Discussion...

.SHORT TERM.../Today/
Issued at 406 AM CDT Mon May 30 2016

The main forecast concern was focused on thunderstorm chances
throughout the day. A few isolated storms have developed along a
weak area of theta-E advection in southeast Iowa and look to
persist through around 12-13z. This ribbon of theta-E extends
northwest close to a weak shortwave moving across South Dakota.
There are already a few storms located in northwest Iowa and
expect them to continue to press east as the theta-E advects north
and east. In addition, there is some weak isentropic lift between
300-315K surfaces and this should be enough to spawn additional
thunderstorms over western to northern Iowa through the morning
hours and into the afternoon as the shortwave transitions east.
However, the better forcing is located over the north today, and
thus have the highest pops going in this location. Severe threat
remains minimal due to the lack of significant deep layer shear to
hold any thunderstorms together. Mainly looking at pulse storms to
produce some brief hail at times.

.LONG TERM.../Tonight through Sunday/
Issued at 406 AM CDT Mon May 30 2016

Strong low level flow will initially be focused on convection west
of Iowa late this afternoon into this evening. Most convection
this evening in the forecast area will be generally isolated and
mainly in western Iowa. The convection across the plains will move
eastward into Iowa overnight as the low level jet veers with time.
Have gradually increased pops during the night from west to east
as the line of storms pushes into the state. While there may be a
severe storm late tonight, the overall system will have matured
by the time it reaches the forecast and will likely be weakening.
The better threat for seeing convection is expected on Tuesday as
the boundary pushes across the forecast areas and lift is enhanced
by the approaching shortwave. Once again, there is some threat for
severe convection, however shear will remain marginal with modest
instability. Some heavy rainfall will be possible given decent
PWATs but the rather progressive nature of the system should
preclude any bigger water issues.

As the front pushes east on Tuesday night, the threat for storms
will diminish and with subsidence overspreading the state, there
will be little threat of precipitation into Wednesday. The quiet
weather is expected to persist from Wednesday into Thursday as
cool Canadian high pressure passes through the region. By Friday,
the next threat of precipitation arrives with increasing warm
advection and theta-e advection ahead of an approaching boundary.

&&

.AVIATION.../For the 12Z TAFS through 12Z Tuesday morning/
Issued at 707 AM CDT Mon May 30 2016

Expecting VFR conditions through much of the TAF period with some
brief periods of MVFR visibility and possibly ceiling, but low
confidence in timing and location of any convection today into
tonight. Mainly handled with VCTS for today until the higher rain
chances late tonight into Tuesday.

&&

.DMX Watches/Warnings/Advisories...None.

&&

$$

SHORT TERM...Podrazik
LONG TERM...Cogil
AVIATION...Podrazik





000
FXUS63 KDMX 291758
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1258 PM CDT SUN MAY 29 2016

.SHORT TERM.../Today/
Issued at 400 AM CDT Sun May 29 2016

The pesky upper level low pressure looks to finally push east of
the forecast area today and allow for surface high pressure to
build into the state. Weak westerly flow and dry air looks to
provide one of the nicer days the state has experience in some
time. Hence, the main forecast concern was focused on temperatures
and how warm they will reach. Leaned slightly warmer than
guidance for max temperatures temperatures today with enough
sunshine and mixing. There is a weak shortwave cutting across
Nebraska, but any convection associated with this system has
diminished. There maybe a stray shower that skirts across the
southwest this afternoon as this shortwave moves through, but low
confidence with anything significant due lack of moisture and
forcing available.

.LONG TERM.../Tonight through Saturday/
Issued at 400 AM CDT Sun May 29 2016

Warm advection and moisture transport will increase overnight
ahead of the next approaching shortwave. This will keep lingering
instability across the state overnight and combined with weak
forcing from the warm advection, may produce a few isolated storms
late tonight. Models diverge somewhat on Monday with GFS
remaining wet statewide as the NAM and EURO remain much drier. GFS
has been overly zealous on its QPF recently and easily convects
with this continuing with this system into early next week. Have
gone with the less ominous EURO/NAM solution and kept convection
isolated to scattered into Monday. Better forcing arrives late
Monday night into Tuesday with the approach of the upper trof.
Convection is expected to develop across the plains on Monday
afternoon near the surface boundary and advect eastward into the
state late Monday night. This convection will persist into Tuesday
ahead of the surface boundary with some threat of severe storms,
albeit somewhat limited given relatively weak shear and modest
instability.

The threat of precipitation will push east on Tuesday night into
Wednesday as the system progresses to the east. Increasing
subsidence on backside of system along with cooler Canadian air
will end precipitation chances by Wednesday night with dry
conditions through the end of the work week. The next threat of
precipitation arrives toward next weekend...although coverage and
intensity appear limited given the relative lack of return flow
into the state.

&&

.AVIATION.../For the 18Z TAFS through 18Z Monday afternoon/
Issued at 1258 PM CDT Sun May 29 2016

Little change to previous update. Iso thunder over the
north/northeast through afternoon at KMCW/KALO. Winds have
increased as well with gusts near 20kts at these sites from WNW.
Otherwise...expect warm air advection/convection to increase
aft 06z at most sites. Coverage may be limited enough...so have
covered for now with VCSH. Cigs to lower to bkn060-110 aft 06z as
clouds spread over the region. Through mid morning expect coverage
to decrease...only to gen up again aft 18z. /rev

&&

.DMX Watches/Warnings/Advisories...
None.
&&

$$

SHORT TERM...Podrazik
LONG TERM...Cogil
AVIATION...REV





000
FXUS63 KDMX 291509
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1009 AM CDT SUN MAY 29 2016

.SHORT TERM.../Today/
Issued at 400 AM CDT Sun May 29 2016

The pesky upper level low pressure looks to finally push east of
the forecast area today and allow for surface high pressure to
build into the state. Weak westerly flow and dry air looks to
provide one of the nicer days the state has experience in some
time. Hence, the main forecast concern was focused on temperatures
and how warm they will reach. Leaned slightly warmer than
guidance for max temperatures temperatures today with enough
sunshine and mixing. There is a weak shortwave cutting across
Nebraska, but any convection associated with this system has
diminished. There maybe a stray shower that skirts across the
southwest this afternoon as this shortwave moves through, but low
confidence with anything significant due lack of moisture and
forcing available.

.LONG TERM.../Tonight through Saturday/
Issued at 400 AM CDT Sun May 29 2016

Warm advection and moisture transport will increase overnight
ahead of the next approaching shortwave. This will keep lingering
instability across the state overnight and combined with weak
forcing from the warm advection, may produce a few isolated storms
late tonight. Models diverge somewhat on Monday with GFS
remaining wet statewide as the NAM and EURO remain much drier. GFS
has been overly zealous on its QPF recently and easily convects
with this continuing with this system into early next week. Have
gone with the less ominous EURO/NAM solution and kept convection
isolated to scattered into Monday. Better forcing arrives late
Monday night into Tuesday with the approach of the upper trof.
Convection is expected to develop across the plains on Monday
afternoon near the surface boundary and advect eastward into the
state late Monday night. This convection will persist into Tuesday
ahead of the surface boundary with some threat of severe storms,
albeit somewhat limited given relatively weak shear and modest
instability.

The threat of precipitation will push east on Tuesday night into
Wednesday as the system progresses to the east. Increasing
subsidence on backside of system along with cooler Canadian air
will end precipitation chances by Wednesday night with dry
conditions through the end of the work week. The next threat of
precipitation arrives toward next weekend...although coverage and
intensity appear limited given the relative lack of return flow
into the state.

&&

.AVIATION.../For the 18Z TAFS through 18Z Monday afternoon/
Issued at 1009 AM CDT Sun May 29 2016

Have added chance of showers over the northeast this afternoon as
weak impulse will bring increase instability to region. May also
see iso thunder...though confidence on coverage small enough to go
with VCSH for now. Remainder of period will be quiet through 04z.
Will evaluate overnight for potential return thunder over south
two thirds...in 18z package. /rev


&&

.DMX Watches/Warnings/Advisories...
None.
&&

$$

SHORT TERM...Podrazik
LONG TERM...Cogil
AVIATION...REV





000
FXUS63 KDMX 291121
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
621 AM CDT SUN MAY 29 2016

...Updated Aviation Discussion...

.SHORT TERM.../Today/
Issued at 400 AM CDT Sun May 29 2016

The pesky upper level low pressure looks to finally push east of
the forecast area today and allow for surface high pressure to
build into the state. Weak westerly flow and dry air looks to
provide one of the nicer days the state has experience in some
time. Hence, the main forecast concern was focused on temperatures
and how warm they will reach. Leaned slightly warmer than
guidance for max temperatures temperatures today with enough
sunshine and mixing. There is a weak shortwave cutting across
Nebraska, but any convection associated with this system has
diminished. There maybe a stray shower that skirts across the
southwest this afternoon as this shortwave moves through, but low
confidence with anything significant due lack of moisture and
forcing available.

.LONG TERM.../Tonight through Saturday/
Issued at 400 AM CDT Sun May 29 2016

Warm advection and moisture transport will increase overnight
ahead of the next approaching shortwave. This will keep lingering
instability across the state overnight and combined with weak
forcing from the warm advection, may produce a few isolated storms
late tonight. Models diverge somewhat on Monday with GFS
remaining wet statewide as the NAM and EURO remain much drier. GFS
has been overly zealous on its QPF recently and easily convects
with this continuing with this system into early next week. Have
gone with the less ominous EURO/NAM solution and kept convection
isolated to scattered into Monday. Better forcing arrives late
Monday night into Tuesday with the approach of the upper trof.
Convection is expected to develop across the plains on Monday
afternoon near the surface boundary and advect eastward into the
state late Monday night. This convection will persist into Tuesday
ahead of the surface boundary with some threat of severe storms,
albeit somewhat limited given relatively weak shear and modest
instability.

The threat of precipitation will push east on Tuesday night into
Wednesday as the system progresses to the east. Increasing
subsidence on backside of system along with cooler Canadian air
will end precipitation chances by Wednesday night with dry
conditions through the end of the work week. The next threat of
precipitation arrives toward next weekend...although coverage and
intensity appear limited given the relative lack of return flow
into the state.

&&

.AVIATION.../For the 12Z TAFS through 12Z Monday morning/
Issued at 619 AM CDT Sun May 29 2016

VFR conditions will prevail through the entire TAF period except
for a brief stint of MVFR ceilings at ALO this morning.

&&

.DMX Watches/Warnings/Advisories...None.

&&

$$

SHORT TERM...Podrazik
LONG TERM...Cogil
AVIATION...Podrazik





000
FXUS63 KDMX 282359
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
659 PM CDT SAT MAY 28 2016

.SHORT TERM.../Tonight/
Issued at 335 PM CDT Sat May 28 2016

Main challenge will be lingering thunderstorms/showers. Upper level
system on track to move east this evening with lessening CAPE during
the evening hours. Will continue thunder through mid evening and
then showers until 10z northeast. Otherwise...gradual diminishment
of convection. Brief heavy downpours and potential for severe will
linger over the northeast this evening. Clouds will also dissipate
through the evening over the south/southwest with cloud cover
lingering northeast. Otherwise expect lows to drop to upper 50s to
lower 60s as slightly cooler air moves in following a weak
trough/cool front. Some concerns for patchy fog toward dawn but with
slightly drier air moving in and winds remaining at 7 to 10kt
overnight...will leave out of forecast for now. Some ground fog is
possible.

.LONG TERM.../Sunday through Saturday/
Issued at 335 PM CDT Sat May 28 2016

Weak upper level shortwave ridge will build behind our departing
wave for Sunday. Despite the rising heights and a surface high, a
few stray afternoon showers and thunderstorms may still develop
across the southwest with steep low to mid-level lapse rates and
MLCAPE values of 1500 to 2000 J/kg as depicted by the NAM. Deep
shear profiles are weak, however, and any convection that does
manage to develop will be poorly organized. Expanded the slight
chance POPs into the SW CWA to cover this possibility. Low level
return flow will set up early Monday morning as the ridge slide
east.

Confidence in the timing and placement of precipitation during
the day on Monday is low. Weak mid-level theta-e advection will
work through a relatively dry airmass, and despite substantial
POPs/QPF being generated by the GFS/EC, model BUFR soundings
remain quite dry and devoid of MUCAPE, especially in the north.
Trimmed back POP categories and coverage based on this
uncertainty. The better threat for thunderstorms will be on
Tuesday as a sharp H300 shortwave dives south out of the Northern
Plains and an attendant cold front shifts across the CWA during
peak heating on Tuesday. After the passage of this system,
northwesterly flow will settle in place downstream of a western
CONUS ridge, helping to bring drier conditions and seasonable
temperatures for the latter half of the week.

&&

.AVIATION.../For the 00Z TAFS through 00Z Sunday evening/
Issued at 653 PM CDT Sat May 28 2016

Expect scattered showers to continue across northern TAF sites
through around 05z Sun. Confidence low to medium for BR at KMCW.
Confidence too low to FM group BR at KALO, but will monitor.
Sunday should bring back VFR conditions.

&&

.DMX Watches/Warnings/Advisories...
None.
&&

$$

SHORT TERM...REV
LONG TERM...Skow
AVIATION...Kotenberg





000
FXUS63 KDMX 281220
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
720 AM CDT SAT MAY 28 2016

...Updated Aviation Discussion...

.SHORT TERM.../Today/
Issued at 409 AM CDT Sat May 28 2016

One more day of this stubborn upper level low pressure system as
it finally kicks east of the state later tonight. Models do agree
on the location of the better forcing in northern Iowa throughout
the day. However, a few of the hires models like the Experimental
HRRR and the NCAR Ensemble suggests a few spotty showers across
the south later this morning towards midday. Regardless, have the
highest pops across northern Iowa. There is a pseudo dry slot
evident on WV imagery sneaking into northwest Missouri and
transfers into southwest Iowa after 12z. Trended dry or lowered to
slight pops across the south for much of the morning. With the dry
slot moving over southern Iowa, the atmosphere likely will have a
chance to destabilize a little and allow for a few storms to
redevelop this afternoon as the trough moves into western Iowa.

Low confidence in any widespread severe potential today, but
certainly cannot rule out the potential for a few funnel clouds near
the upper low as it moves across northern Iowa. Even though the 0-1
km bulk shear is not favorable, there is decent vorticity present
with the upper low in northern Iowa by around 21z. This combined
with with maybe enough 0-3km CAPE (200-300 J/kg) and steep 0-1 km
lapse rates (8.0-9.4 C/km) to see a funnel cloud or two develop
across the northern portion of the forecast area this afternoon.
Very low confidence in anything reaching the surface today.

.LONG TERM.../Tonight through Friday/
Issued at 409 AM CDT Sat May 28 2016

Upper low will be departing tonight with subsidence increasing
across the state. Evening showers and a few storms will decrease
in coverage as the evening progresses and lift weakens with little
if any precipitation expected after midnight. Skies will clear as
drier air spreads into the state overnight with cooler
temperatures. Sunday is expected to be relatively quiet across the
state although there is some concern as a weak shortwave passes
through the state. This wave may produce a few showers as it moves
overhead and will continue to monitor to see if any pops need to
be introduced. Otherwise, warm advection will begin by later in
the afternoon in response to the next system dropping into the
northern Rockies.

Weak lift with the warm advection in additional to weak theta-e
advection will increase the threat for isolated thunderstorms on
Sunday night into early Monday. However, the better threat of
storms will arrive Monday afternoon into Tuesday as forcing from
the approaching system arrives. Still some threat for severe
weather and will continue to monitor to see the extent of any
severe storms. After this system passes, the weather appears quiet
for several days for the latter half of next week along with
cooler air as canadian high pressure drops into the upper Midwest.

&&

.AVIATION.../For the 12Z TAFS through 12Z Sunday morning/
Issued at 722 AM CDT Sat May 28 2016

IFR ceilings will diminish at OTM by around 13z with the dry slot
moving across southern Iowa. Otherwise, expecting showers and
thunderstorms to redevelop over northern Iowa and mainly impact
OTM and MCW. Potential for MVFR ceilings this evening into Sunday
morning and have mention across northern TAF sites.

&&

.DMX Watches/Warnings/Advisories...None.

&&

$$

SHORT TERM...Podrazik
LONG TERM...Cogil
AVIATION...Podrazik





000
FXUS63 KDMX 280522
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1222 AM CDT SAT MAY 28 2016

...Updated Aviation Discussion...

.SHORT TERM.../Tonight/
Issued at 349 PM CDT Fri May 27 2016

Negatively-tilted H300 trough axis currently over the Texas
Panhandle will lift northeast tonight into east central KS, helping
to fuel the next round of showers and storms for Iowa. At the
surface, a broad surface trough encompasses the state with multiple
embedded outflow boundaries courtesy of this morning`s convection.
The break between these two rounds of precis will be short-lived,
with the next round of multi-cellular convection already developing
across eastern Kansas and western Missouri. Most synoptic and
mesoscale models are in good agreement on the timing of this precis
but are struggling with the overall areal extent and amounts. Leaned
towards the 27.18Z HRRR and GFS with the placement of the heaviest
rainfall/highest POPs. Axis of elevated H700-500 mixing ratios will
lift north through Iowa between 00 and 09Z with the best chance of
heavy rainfall over the southeast CWA. RUC/NAM/GFS soundings for Des
Moines and west are rather dry below 800mb, lending further
confidence in the heaviest rainfall falling in the east. Localized
heavy rainfall will be the biggest threat from these storms tonight
given the weak to modest instability profiles and weak flow below
600 mb.

.LONG TERM.../Saturday through Friday/
Issued at 349 PM CDT Fri May 27 2016

The primary concerns remain the slow evolution of the current Plains
long wave trough and the next northern stream long wave cycle toward
the middle of next week. Potent short wave/PV anomaly should be
right along the NE/IA border at 12z with fairly decent synoptic
scale rise/fall couplet moving through northern Iowa. The high res
models do not depict the areal coverage one might expect versus this
degree of forcing, but confidence is still there that weak
convection will be lifting toward the Minnesota border in the 09-15z
time frame so pops remain high. Peak heating convection will likely
follow, mainly over central and southeastern sections by
afternoon as well. MLCapes looks to be in the 1.5-2.5k j/g range
with only moderate deep bulk shear. Thus agree with SPC midday Day
2 outlook pulling the Marginal Risk back farther to the north and
west. None of the threat probs are particularly high, but hail,
wind and tornadoes are all still on the table depending on how
much cells organize due to limited shear. Even non-supercell
tornadoes are possible considering low LCLs and 0-3km Capes 100
j/kg or more.

The potential should decrease into the evening with the loss of
large scale forcing and heating with only low chances relegated to
far northeastern sections into early Sunday morning. This will lead
to a relative min and dry break Sunday into Sunday Night before the
attention again turns upstream. Unfortunately the evolution of the
long wave pattern next week is not clear cut with initially some
timing issues with the surface reflections into Tuesday, and the
degree of long wave phasing into Thursday. There is low confidence
in this time window with individual GEFS H5 members leaning both
toward the operational run and the ECMWF. As far as sensible
weather, this would result in relatively higher confidence in
weak warm advection convection crossing the Missouri Valley Sunday
Night into Monday. This could potentially continue into Tuesday as
well, but questions arise with regard to the proximity to the
surface trough and potential low level convergence during
afternoon peak heating. The faster ECMWF solution would be more
conducive with the slower GFS less so and favoring weak warm
advection precis lingering into the night with a farther west
genesis region. The ECMWF would suggest precis exiting with
mainly dry northwest flow while the GFS hangups up a drifting
upper low through the Central Plains. Would tend to favor more
phased ECMWF solution at this point with the GEFS and ECMWF
ensembles pointing in that direction and although neither are
great, the ECMWF has slightly better run to run continuity and
passes the eye ball test better. Thus have keep only some slights
going into the end of the next work week lending the GFS just a
little credence.

&&

.AVIATION.../For the 06Z TAFS through 06Z Saturday night/
Issued at 1213 AM CDT Sat May 28 2016

Widespread SHRA with some TSRA expected across the region overnight
as an upper level storm system moves through. Mainly VFR conditions
expected...except for some brief MVFR vsbys or cigs especially at
the KOTM and KDSM terminals. Expect a temporary lull in precip
chances on Saturday morning across the south...but returning by
midday before moving out by late Saturday evening.

&&

.DMX Watches/Warnings/Advisories...
Flash Flood Watch until 7 AM CDT this morning for Adair-Adams-
Appanoose-Cass-Clarke-Davis-Decatur-Lucas-Madison-Mahaska-Marion-
Monroe-Ringgold-Taylor-Union-Wapello-Warren-Wayne.

&&

$$

SHORT TERM...Skow
LONG TERM...Small
AVIATION...Zogg





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