079
FXUS63 KEAX 061629
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
1129 AM CDT Sat Jul 6 2024

.KEY MESSAGES...

- Storm chances increase this evening and tonight. A few strong
  storms are possible but the threat of severe weather is low.

- Precipitation chances may continue into Sunday, with better
  chances Sunday night into Monday.

- Near to slightly below normal temperatures through the middle
  of next week with a trend to above normal late in the week.

&&

.DISCUSSION...
Issued at 316 AM CDT Sat Jul 6 2024

Broad upper troughing prevails across the middle of the country with
upper-level ridging over the eastern Pacific and a closed low
in the western Atlantic within broad ridging. This has set up
northwesterly flow across the central and northern Plains into
the lower Missouri Valley. Water vapor imagery shows a series
shortwave troughs embedded within this flow early this morning.
The first is moving into western South Dakota as of 08Z with an
area of thunderstorms associated with the forcing from that
wave. The second shortwave is farther northwest, in southern
British Columbia and Alberta. As easternmost shortwave moves
southeastward through the day, there will be modest moisture
advection northward into eastern KS and NW MO. This moisture
return will help increase instability but the combination of
CAPE and shear still doesn`t look that impressive. The main
limiting factor will be instability with nearly a 100% chance of
over 1000 J/kg but likely not exceeding 1500 J/kg. This just
isn`t much available potential energy for July. But it`s enough
that given the shear in excess of 30kts, may support a few
strong storms during the late afternoon to early evening hours.
Instability quickly diminishes into the overnight, limiting the
potential for strong to severe storms

The second shortwave seems to phase with the broader upper trough
and that trough deepens over the northern Plains and Upper Midwest.
With the trough deepening in the region the pattern has
potential to be unsettled. But there is more uncertainty through
this period as models are not in good agreement with the
thermodynamic profiles and boundary location(s). Ensemble
guidance shows 40-50% probabilities for at least 0.01" of rain.
Probabilities decrease quickly with higher rain amounts. All
this indicates that while we have 40-50% PoPs in the forecast
for Sunday afternoon, it may not be a washout and, in fact,
could be dry for most/ all of the afternoon time frame.
Precipitation chances shift east throughout the forecast area
Sunday night as the upper trough slowly shifts east. Again,
there is a fair amount of uncertainty with a 50-60% chance for
at least 0.01" with probabilities falling quickly as amounts
increase over 0.25". However, there are small probabilities (5%
or less) of rain amounts in excess of 1.5" Sunday night into in
eastern KS and western MO. So while it`s likely there will be
some precipitation during this time frame, there is a very small
chance for heavy rain. The pattern is just too nebulous at this
point to have much confidence in this.

Temperatures look to be near normal through the middle of next week.
The upper pattern will remain fairly steady through next
Wednesday and Thursday. LREF clusters show little variation
with the upper ridge dominating the western US and broad
troughing over the central US to the Great Lakes region. By the
end of next week, that troughing starts to weaken/ shift further
east and that allows the ridge to start expanding eastward into
the middle of the country. So by next Friday and Saturday,
temperatures climbing into the 90s looks more likely. Isolated
convection can`t be ruled out in this pattern but at the moment
there is not a strong enough signal to mention anything more
than diurnally driven slight chance PoPs.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 1126 AM CDT Sat Jul 6 2024

VFR conditions through the period. Could see some fair weather
cumulus across central and eastern Missouri this afternoon.
Potentnial for a few storms this evening across northern
Missouri after 00Z, but should be confined to areas north of
highway 36. Rain chances increase across the region throughout
the day on Sunday, though timing is ill- defined at this point
so left the mention out at this time.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...None.
KS...None.

&&

$$

DISCUSSION...CDB
AVIATION...BT