Area Forecast Discussion
Issued by NWS Springfield, MO
FXUS63 KSGF 302105
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
305 PM CST Sat Nov 30 2013
.SHORT TERM...(Today and Monday)
Beautiful weather in progress over extreme southeast Kansas and
the Missouri Ozarks. Temperatures reached the lower 60s in some
spots, under sunny skies and southerly breezes.
For tonight, we leaned the temperature forecast with the
adjusted MET biased corrected guidance, since it`s been the best
verifying model for the past three nights. This will be an
increase in lows for most areas.
We also think fog will develop along and north of Interstate 44
toward the early morning hours of Sunday. Visibilities could
fall below one mile at times.
Slightly cooler temperatures are expected for Sunday as a weak
frontal system stalls over southern Missouri. An increase in
cloud cover could also facilitate cooler temps in the low to mid
By Monday, southerly winds return while full sunshine is expected.
This will lead to temperatures back into the upper 50s and lower
60s. No precipitation is expected through Monday.
.LONG TERM...(Monday Tonight through Friday)
Before we get too deep into the extended discussion, major
differences between the GFS and the ECMWF were noted in their 12Z
solutions. These differences will have big time ramifications on
wintry precipitation chances toward the end of the week.
Collaboration with the Weather Prediction Center this afternoon,
led to a forecast heavily leaned with the ECMWF. As a matter of
fact, the model diagnostics specialist is completely throwing out
the GFS solution, regarding the structure of the upper trough late
in the week.
Essentially the upper low, currently over northwest Canada, will
sag into the western United States as the week progresses. It is
expected that this feature will dig deeper, and hold back over the
Mountain West for a longer period of time, prior to ejecting it`s
main upper speed max over the Ozarks...after...the cold Arctic air
surges through southern Missouri.
This solution will greatly increase the chances for accumulating
wintry precipitation over the entire extreme southeast Kansas and
Missouri Ozarks Region Thursday night into Friday.
At this point, we are still 6 and 7 days out, so we will not get
cute with pinpointing precipitation types and amounts. However, we
have decided to mention a risk for accumulating wintry
precipitation into the Hazardous Weather Outlook.
If you follow the GFS, no wintry precipitation occurs, due to the
model progressing the Canadian low, and shearing it out too fast
through the work week. Again, this is not the recommended solution
to lean next week`s forecast on.
Stay tuned for further updates regarding the possibility of wintry
weather late in the upcoming work week.
.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 1150 AM CST SAT NOV 30 2013
VFR conditions will continue into early this evening with brisk
southwest winds diminishing by sunset. A band of scattered to
broken clouds in the 2500-4000 foot layer is then expected to
develop and slowly shift south across the area from late this
evening into the overnight period. These clouds will result in
periodic MVFR ceilings. As the back edge of this cloud band slowly
shifts south across southern Missouri, there is a strong signal for
dense fog development. While timing is still in question,
confidence in dense fog development is high enough that LIFR was
included in prevailing groups late tonight and early Sunday
morning at JLN and SGF. At this time, it looks like the dense fog
will develop sooner at JLN as clouds will decrease earlier. The
forecast is much tougher for BBG as the clouds may not clear until
around sunrise. Thus, the window for dense fog development is much
smaller. We have handled this with a TEMPO group to IFR. Flight
conditions will only slowly improve Sunday morning as the low sun
angle will have a difficult time burning off the fog.