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Area Forecast Discussion (AFD)

Issued by Springfield, MO (SGF)

                            
000
FXUS63 KSGF 192123
AFDSGF

Area Forecast Discussion
National Weather Service Springfield MO
323 PM CST Tue Feb 19 2019

.SHORT TERM...(This evening and Tonight)
Issued at 115 PM CST Tue Feb 19 2019

An upper level trough is currently spreading east into the
southern Plains early this afternoon. The trough will spread 
northeast across the Plains tonight and the area on Wednesday. 

Ahead of the trough temperatures are currently in the lower to
upper 30s with dew points running 10 to 20 degrees cooler than 
current temperatures. Lift will overspread the area this afternoon
from south to north into this evening. The dry air currently in 
place across the area will have to be overcome to get 
precipitation to the ground. With fairly strong lift spreading 
in, the dry air will be able to overcome pretty quickly as the 
layer saturates with precipitation falling through it. As the dry
air is overcome, temperatures will cool to the to around 30 to 32
degrees when the precipitation starts.

When the precipitation begins this afternoon it will start off as
all snow or a rain snow mix closer to the MO/AR border. Moderate 
to periods of heavy snow will be possible as this band of snow 
lifts north across the area into early this evening. The snow will
be fairly short lived, but given the intensity of the snow a 
quick 1 to 2" are expected to occur, with locally heavier amounts 
possible. The rates should support slushy road conditions for the 
afternoon/evening commute. Once the snow rates start to decrease,
its quite possible the snow starts to melt some on roads, 
especially farther to the south. 

A warm nose will start to spread north into the area this evening
causing the snow to become more rain across south central 
Missouri. Some elevated instability will also develop across south
central Missouri allowing a few rumbles of thunder to be 
possible. The convective nature could also allow some pockets of 
sleet to develop across south central MO this evening. 

Farther to the north and west the bigger player on precipitation 
type will be the loss of cloud ice as a strong dry slot moves 
across the area. Low level moisture will remain high this evening
overnight once cloud ice is lost, and lift will occur within this
low level moisture. This will result in more freezing drizzle or 
drizzle occurring later this evening through the overnight hours. 
Surface temperatures are going to be really tricky overnight they 
should be around the freezing mark, just one degree could be the 
difference between freezing drizzle and drizzle. Its possible 
temperatures warm overnight or bounce around. With temperatures 
near the freezing mark a few slick spots will be possible 
overnight, mainly on bridges and overpasses. Generally a glaze to 
around a tenth of an inch of ice are expected with locally heavier
amounts up to two tenths possible this evening through the 
overnight hours.

.LONG TERM...(Wednesday through Tuesday) 
Issued at 315 PM CST Tue Feb 19 2019

As the storm system pushes off to the north and east early 
Wednesday morning, the potential for drizzle will remain possible 
across central Missouri through about noon. Temperatures for 
Wednesday will generally top out in the mid/upper 30s across east 
central Kansas to the low/mid 40s across south central Missouri.

Upper level ridging will allow for a warming trend through the
late part of the week with quite weather expected through 
Thursday night. The highs Thursday and Friday will top out in 
middle 40s to the lower 50s.

The next system to take aim at the Middle Mississippi Valley will
be a deep trough ejecting out across the Central Plains Friday
into Saturday. Models suggest that there will be chances for 
showers Friday during the afternoon into the evening, mainly 
across south central Missouri along the AR/MO border. However, the
main show looks to take place Saturday.

By Saturday, temperatures will warm into the upper 50s to the
lower 60s across the Ozarks as strong warm air advection is 
ushered in by southerly winds. This system will be accompanied by 
a strong shortwave that will be ejecting out across the region. 
Models suggest the trough becoming negatively tilted with 
cyclogenesis taking place across the Texas panhandle region early 
Saturday. By Saturday afternoon, a surface low will begin to lift 
across western Kansas, tracking to the northeast. As a result, 
showers and thunderstorms will increase in coverage across the 
region on Saturday. Current models suggest fairly strong synoptic
features to come together. The strongest area of lift will be 
focused across the Southern Plains into the Middle Mississippi 
Valley. Models show strong divergence aloft over the Ozarks 
region, being in the left exit region of both an upper level jet 
streak and the a building low level jet. As for the availability 
of moisture, a building 50-60 knot LLJ will transport moisture 
northward out ahead of the cold front, allowing dewpoints to climb
into the lower 50s across the region with PWAT values of 1.00 to 
1.25 inches. Furthermore, model soundings suggest there will be a 
significant amount of deep layer shear. On the flip side, 
instability continues to be on the marginal side with generally 
less than 500 J/Kg of MLCAPE. However, this could be sufficient 
enough. Bringing all these ingredients together, there is an 
increased likelihood of showers and thunderstorms with this system
Saturday, and there could be a risk for severe thunderstorms. At 
this time, the SPC highlights a 15% severe weather Day 5 outlook 
generally along and southeast of I-44. This potential threat for 
severe weather was also highlighted in the CIPS Experimental 
Analog-Based Severe Probability Guidance across southwest Missouri
for Day 5. There will also be a flooding threat with this system 
across much of southern Missouri were grounds are already 
extremely saturated. In all, will continue to look for model 
consistency and trends in the coming days.

Behind this system, temperatures will return to the middle to upper
40s for Sunday with gusty winds behind the exiting system. There
will be a slight warming trend into early next week with highs 
topping out in the low 50s Monday and Tuesday. Overall, the 
pattern looks to be less active at the early part of next week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1204 PM CST Tue Feb 19 2019

Ceilings will gradually lower this afternoon with rain and snow
moving south to north across the Missouri/Arkansas state line. 
IFR will become highly likely by sunset due to falling snow and 
lowering ceilings.

Precipitation will then change to sleet and freezing rain
throughout the evening before then changing to freezing drizzle
and drizzle overnight. IFR and areas of LIFR conditions are 
expected overnight.

Surface winds will veer from southeast to southwest through the
TAF period.


&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...Winter Weather Advisory until 6 AM CST Wednesday for Moz055>058-
066>071-077>083-088>098-101>106.

KS...Winter Weather Advisory until 6 AM CST Wednesday for KS-097-
101.

&&

$$

SHORT TERM...Wise
LONG TERM...Perez/Wise
AVIATION...Albano