Area Forecast Discussion
Issued by NWS Springfield, MO

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FXUS63 KSGF 241751 AAB
AFDSGF

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1151 AM CST Wed Dec 24 2014

.UPDATE...
Issued at 1150 AM CST WED DEC 24 2014

Main axis of the upper level trough continues to edge eastward at
this hour. Still continuing to see light precipitation echoes on
regional radar and a variety of precip types (drizzle, light snow,
light rain and a mix). Cloud top temperatures are still riding
-15C, which is right at the critical threshold for ice crystal
presence in the cloud layer. Going forecast of mid/upper 30s temps
and a mix of light rain/snow/drizzle handles things quite well and
will continue to tweak the timing of when this precip will exit
to the east.

UPDATE Issued at 905 AM CST WED DEC 24 2014

Forecast tweaked just a bit to account for the latest radar and
satellite trends.

The main upper level trough is shifting to the east and radar
echoes have expanded a bit over the past. In addition, IR
satellite indicated just enough cooling along to support ice
crystals in the clouds. As a result we have received reports of
drizzle, light rain and light snow during the past hour.

Light snow will be most prevalent where IR satellite temperatures
are lower than -15 C and radar echoes exceed about 15 dBZ. Cloud
temperatures are really hugging that -15C threshold, so
precipitation types will be variable and fleeting into early this
afternoon. With temperatures firmly in the middle 30s and snow
rates looking to be light, little if any accumulation is expected.
If there is accumulation, it will be very light on grassy areas
and melt once any snowfall ends.

Clouds will hang around the rest of the day, with gradual clearing
expected to begin in the west by sunset.

&&

.SHORT TERM...(Today and Tonight)
Issued at 212 AM CST WED DEC 24 2014

Surface low was located over Tennessee along a frontal system
which stretched from the Ohio valley into the Gulf of Mexico early
this morning. The main upper level trough axis was located along
the western edge of our CWA. The surface low will continue to lift
northeast today into the Ohio valley and into southeast Michigan
by this evening. Meanwhile the upper level trough will shift east
across the CWA today. The light precipitation currently to our
west will shift eastward into the area today with temperatures
expected to remain at or above freezing. The light precipitation
will initially begin as rain or a rain snow mix and may change
over to all snow by 13-14z. With temperatures remaining above
freezing, not expecting much accumulation to occur and have
roughly a half inch as our highest amounts during the day today.
The bulk of the precipitation will remain closer to the surface
low track which will be well east of our CWA.

Should see clearing from west to east this evening/overnight, but
west winds back around to the south with southwest flow around 850
advecting in a warmer air mass into the region. So even though we
clear out tonight, lows will manage to remain in the mid to upper
20s.

.LONG TERM...(Thursday through Tuesday)
Issued at 212 AM CST WED DEC 24 2014

Christmas day should be sunny for much of the day with breezy
south winds occurring out ahead of the next area of low pressure
developing in the high Plains. Temperatures should rise back into
the upper 40s to mid 50s. The mild temperatures will continue into
Thursday night with lows in the mid 30s to low 40s.

Friday will be another mild day with the cold front approaching
from the west. There may be a slight chance of a shower ahead of
the front, but most of the upcoming precipitation will be behind
the front. The front will move through Friday night with colder
air pushing in behind the front. May see rain change to a
rain/snow mix or change over to all snow. ECMWF continues to bring
more precipitation to the area with this system as it tracks
several areas of low pressure along the frontal boundary and is
slower to move the front through than the GFS. Have gone with a
blend of the models at this point which continues pops through
Sunday night in the eastern CWA. Temperatures again, will be on
the borderline with rain/snow so not expecting much in the way of
accumulating snow at this point.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 1150 AM CST WED DEC 24 2014

Near term concerns revolve around lingering light
rain/snow/drizzle and stratus. As discussed in the above update,
this precipitation will persist for a few more hours this
afternoon before exiting stage east. Lowest ceilings will be with
precipitation with IFR expected at SGF for a couple more hours.
All sites will be MVFR from mid afternoon into this evening.
Question becomes just how orderly the stratus will exit. At this
point, clearing at JLN will be this evening, with SGF/BBG around
midnight tonight. Attention then turns to gust south wind
potential on Christmas Day. Speeds will ramp up during the late
morning, with gusts in excess of 30kt at JLN/SGF just beyond the
end of the forecast.

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$

UPDATE...Gagan
SHORT TERM...Lindenberg
LONG TERM...Lindenberg
AVIATION...Gagan





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