Area Forecast Discussion
Issued by NWS Springfield, MO

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FXUS63 KSGF 172349 AAA
AFDSGF

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SPRINGFIELD MO
649 PM CDT Wed Sep 17 2014

...Mesoscale Discussion and Updated Aviation Section...

.MESOSCALE DISCUSSION...
Issued at 649 PM CDT WED SEP 17 2014

Convection continues to propagate southwestward with time with
nearly all activity across northeastern Oklahoma and northwestern
Arkansas. Aside from a few lingering storms across far
southwestern Missouri, most locations will likely be dry for most
if not all of the evening.

Concerns are two fold for after midnight. First, will we see
redevelopment of showers and storms over northwestern Kansas and
second, the potential for fog development.

Recent runs of the HRRR have been handling ongoing activity fairly
well. These runs indicate another batch of storms developing over
northwestern Kansas later this evening and then riding a low level
boundary southeast toward the area. MUCAPE looks best to our
southwest, and this is likely where the bulk of any activity that
does develop will move. Unlike last night, the low level jet
tonight does not look nearly as impressive. In fact it is rather
ill defined, giving credence to any complex of storms propagating
closer to where the better instability will reside. That said, we
still cannot rule out a complex of storms clipping the
southwestern portion of the outlook area later tonight into
Thursday morning. It should be noted that several convection-
allowing short term models do not develop any activity. The 18z
NAM is by far an outlier and initialized quite poorly. As a
result, this model is discounted.

As far as fog potential is concerned, this is a conditional risk
based on whether or not we see an additional complex of storms, or
at least high level "blow off" clouds from a complex just to our
west. LAMP and MOS are insistent in developing fog across much of
the area. If we can clear out, certainly areas where rain fell
today will be prone to fog development. In addition, it appears
cross over temperatures will be exceeded across central Missouri.
This strongly suggests fog development if skies can remain clear.
Will continue to monitor observations and incoming near term model
runs to refine the risks of both the fog and rain chances.

&&

.SHORT TERM...(This Evening through Thursday)
Issued at 229 PM CDT WED SEP 17 2014

Well its been a little more active than previously thought. Models
did not handle today`s situation very well and confidence in
tonight`s forecast is low.

A frontal boundary is currently stalled from roughly near
Lamar to Roaring River State Park. West of that boundary
temperatures are in the middle 80s and over the eastern Missouri
Ozarks...temperatures were in the 60s. Convection continues to
regenerate near that boundary and has shown signs of moving slowly
westward.

The short term models are in a bit of a disagreement on the next
12 hours. But the over all trend was to move the axis of
convection slowly westward this evening. Temperatures will be
again tricky tonight through tomorrow. One note to add is there is
another very subtle mid level wave on the Water Vapor imagery over
western Nebraska that is riding southeastward it the mid level flow.

The big question mark is how this will interact with the boundary
in the area overnight and if there will be a similar repeat of
overnight convection developing late tonight through early
tomorrow morning. Will maintain highest chances for additional
convection over portions of southeast Kansas and far southwestern
Missouri for the rest of the evening and tonight.

Even though we have seen some heavy rainfall in the Springfield
area from earlier convection...no headlines for any flash flood
watches because the new development tonight should be southwest of
where the heavy rainfall fell today. There will still be a chance
for an isolated strong storm or two through tonight with marginal
severe hail and wind gusts up to 50 mph with the strongest
convection.

Will have the chance of rain diminishing through out the day on
Thursday as upper level ridging begins to move in and cut off rain
chances. Temperatures will be warmest out west tomorrow...low 80s
and coolest out east...low 70s

.LONG TERM...(Thursday Night through Wednesday)
Issued at 229 PM CDT WED SEP 17 2014

Warm and dry weather with high pressure in the upper levels on
Friday and for most of the day on Saturday. A front will move in
late afternoon and overnight Saturday to bring additional showers
and thunderstorms. Look at the upper level flow and the leftover
moisture from the tropical system out in the southwest U.S...looks
like that will mainly stay southwest of our area and most of the
energy with the trough will stay up in the Great Lakes Region over
the weekend. Will continue to maintain the chance for rain this
weekend but not expecting anything heavy at this time.

The front clears through on Sunday with gradual clearing and
drying. A Canadian airmass moves in for early next week with
seasonable Fall like weather.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday Evening)
Issued at 649 PM CDT WED SEP 17 2014

Very complicated forecast for tonight. There is a conditional risk
for fog at all sites, especially SGF/BBG where heavy rain fell
today. There are also signals for another complex of storms to
clip the area late tonight. If these storms do materialize, fog
will be a lesser risk. If we can stay clear, fog will be a much
greater risk. Much will depend on the evolution of mesoscale (and
finer) details in the next few hours. Will utilize amendments to
change course if/when needed. If fog is the winner tonight and
storms do not materialize, LIFR conditions are possible, gradually
improving during the daylight hours of Thursday morning. VFR is
expected Thursday afternoon.

&&

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

$$

MESOSCALE...Gagan
SHORT TERM...Griffin
LONG TERM...Griffin
AVIATION...Gagan






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