National Weather Service Raw Text Product

674 
FXUS63 KDMX 030823
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
323 AM CDT Sun Jul 3 2022

.SHORT TERM.../Today through Monday/
Issued at 323 AM CDT Sun Jul 3 2022

Forecast Impacts for the week: 

...Storm chances increase tonight
...Heat and humidity/periods of storms Monday to Thursday
...Warm conditions persist remainder of extended

Confidence Short Term: Low to Medium

High pressure continues over the eastern half of the country
early today with low pressure across the west. A ridge at H850 
extends to western Iowa while the main moisture pool extends from 
the Gulf Coast through much of the Southern Plains. The mean H850 
flow increases from the south just to our west and by later 
tonight it will return to cover most of the state as the ridge 
pulls east. For now, a fairly dry airmass continues over most of 
Iowa. Convection remains fairly unorganized over the Central US 
early this morning as little in the way of forcing is present 
other than a weak boundary over Montana southeast to northwestern
Iowa and another boundary south across southern Missouri to 
Oklahoma. 

Confidence in general trends remains high, but overall details 
becoming more muddled due to the spread of solutions in convective 
trends later tonight into Monday afternoon. Today will remain 
quiet with warmer and more humid conditions expected than 
yesterday as the ridge pulls east and southerly winds increase. 
The weak warm front over northwestern Iowa now will lift north 
into Minnesota this afternoon with some convection continuing to 
fire along the boundary well north of the region this afternoon. 
Highs today will reach the mid to upper 80s over the region. The 
southern boundary over Missouri and Kansas is expected to lift 
north tonight. There is good consensus in initiation of thunderstorms
over southeast Nebraska and northern Kansas between 03 and 06z. 
Though both the Euro/GFS solutions have the area of storms moving 
into Iowa after 06z, the GFS weakens the convection overnight 
while the Euro continues to develop more convection through time. 
The NAM continues to be the most robust of the 3 solutions and 
also initiates convection in about the same location. Climatology 
would suggest that the convection will continue east once it 
begins and have continued a more widespread PoP chance across the 
area through Monday morning. There should be no shortage of 
available moisture and though shear is marginal, chances for brief
heavy rainfall remain high with PWATs over 2 inches and warm 
cloud depths over 4000m. Depending on the convective coverage late
tonight into early Monday, rainfall amounts of 1 to 3 inches are 
possible in any heavier convection. Lows tonight will fall to the 
upper 60s to lower 70s over most of the area with the return of 
southerly flow. Though tomorrow will be hot and heat headlines are
likely to be needed over a good share of the area in the west and
south, there is still some uncertainty regarding the amount of 
cloud cover and any lingering convection into the late morning or 
early afternoon. Both factors will impact the area of warmer highs
and greater concern for heat impacts. Highs will certainly reach
the 90s over the west/south with some 80s in the far northeast.The
NAM/GFS are more aggressive in moving the boundary north while 
the Euro is holding onto some additional convection developing in 
the afternoon. Current HRRR output also suggests lingering cloud 
cover and some potential for convection.

&&

.LONG TERM.../Monday Night through Saturday/
Issued at 323 AM CDT Sun Jul 3 2022

Confidence: Medium

With a fair amount of the forecast being dictated by the mesoscale, 
confidence is more limited again for Monday night into Tuesday as 
the front hangs up in central or northern Iowa. The NAM/GFS with 
their more northerly bias keeps the boundary over northern Iowa 
into Tuesday morning, while the Euro shows strong convection 
developing just north of the boundary in northern Iowa Tuesday 
evening; eventually driving the boundary south into Tuesday 
morning as the storms track east. With no real change in airmass 
characteristics, another round of storms with the potential to 
drop several inches of rain is expected Monday night in an area 
bounded by northern Iowa to southern Minnesota and Wisconsin. 
Model differences continue to stem from how deep each forecasts 
the H700 warm layer. Looking ahead to Tuesday, H850 temperatures 
are now trending downward in both the GFS/Euro deterministic 
models while the GEFS continues in the mid 20C across the south. 
Though we continue with mid to upper 90s forecast in the south 
Tuesday based on ensembles, that may need to be adjusted downward.
Much depends on the mesoscale this period. The remainder of the 
forecast still appears to be very warm with continued chances for 
some storms through Friday. The stubborn boundary is expected to 
linger over the area for at least another 3 to 4 days which will 
keep us very warm, humid with periodic chances for storms. Finally
by later Friday into Saturday, a back door push of Canadian air 
and high pressure is anticipated to move into the Great Lakes, 
providing both some relief from the hot weather and a slightly 
less humid airmass to move into the region. Highs will remain in 
the 80s for most of the week with lows mainly in the 60s by late 
week. 


&&

.AVIATION.../For the 06Z TAFS through 06Z Sunday night/
Issued at 1137 PM CDT Sat Jul 2 2022

VFR conditions are expected this period. Clear skies and light
southeast winds are expected overnight. Will likely see diurnal 
cumulus after 17Z Sunday along with breezy SE winds. There is 
potential for thunderstorms Sunday night but the latest guidance 
indicates impacts will be after this period. 


&&

.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...REV
LONG TERM...REV
AVIATION...Fowle