Area Forecast Discussion
Issued by NWS Springfield, MO
FXUS63 KSGF 231847
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
147 PM CDT Thu Apr 23 2015
.SHORT TERM...(This Evening through Friday)
Canadian high pressure shifted east of the Ozarks today. This will
allow southerly flow and moisture advection to commence this
evening and tonight, in advance of an approaching storm system.
This speed max was located over the Baja of California, and will
take a direct path toward the Missouri Ozarks over the 24 hours.
Starting with tonight, the higher resolution NAM supports the
development of a low level jet directed into southeast Kansas and
southwest Missouri. 925 to 700 mb moisture transport vectors
maximize values in this region between 3am and 7am, forcing
showers and thunderstorms to develop. We think through 12z, this
precipitation will be more confined to areas along and west of
Highway 65. Therefore we have focused the highest POPS over SE
Kansas and SW MO.
This warm advection regime will also bring considerable cloud
cover to all locations tonight, helping to keep overnight lows
ranging from the upper 40s to the middle 50s.
A resulting increase in instability will lead to chances for
strong to severe thunderstorms late Friday afternoon into Friday
Storms Friday afternoon and evening are expected to develop along
a dry line, and a triple point somewhere over eastern Kansas.
It remains unclear at this time, if these storms will move into SE
Kansas or western Missouri. There are some mixed signals in
model data at this time.
The other question mark we need to watch very closely, is the
possibility of storms developing between 21-00z Friday afternoon,
in response to a 700 mb wave passing through. At this exact time,
convective inhibition weakens to less than 20j/kg from a mixed
layer parcel due to peak heating.
Mixed layer CAPE are progged to remain marginal, or less than 1000
j/kg. So even if storms do develop across the western Ozarks,
storm strength and resulting impacts are tough to discern at this
With these uncertainties, our severe weather forecast and message
will remain in line with the Storm Prediction Center`s forecast.
It`s clear that understanding the short term environment will be
very important from Friday afternoon through Friday night.
.LONG TERM...(Saturday through Thursday)
For the most part, we think all thunderstorms will have exited
east of the Ozarks by Saturday morning. There are some signals
that a few showers could develop in central Missouri, as a cold
front shifts across the region Saturday afternoon.
A drier and cooler airmass will keep precipitation chances out of
the forecast from Saturday night through Sunday afternoon.
Rain chances once again increase Sunday night and Monday, as yet
another upper level low approaches from the west. Both the GFS and
the ECMWF have this feature closed off from the northern belt of
westerlies, therefore it shifts eastward slowly.
The GFS is a little more bullish with precipitation early next
work week, with a more northern track of this upper low center.
Meanwhile the ECMWF has trended south with it`s tracking,
confining rainfall into areas near the Interstate 40 corridor. Our
guess is the GFS has a better handle on this system, and we need
to plan for rain chances Monday into Tuesday.
All indications point toward beautiful and quiet spring time
weather Wednesday - Friday of next week. An upper ridge builds
across the nation`s midsection, allowing for an eventual return of
southerly breezes combined with plenty of sunshine.
.AVIATION...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 1212 PM CDT THU APR 23 2015
Winds starting to increase and become southeasterly at the TAF
locations. The increased wind was in relation to the pressure
gradient tightening up with the departing high pressure and
developing low pressure in the high Plains. A low level jet will
develop overnight and a warm front will begin to lift north
through the area on Friday. Showers and thunderstorms will be
possible in association with the low level jet overnight and into
Friday morning but should clear by mid to late morning. The area
will then become capped after the warm front moves through to the
north towards midday Friday and the end of the 18z TAF. Generally
expecting VFR conditions outside of convection, but may see some
MVFR develop within showers/thunderstorms.