Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 070911

411 AM CDT Thu May 7 2015

.SHORT TERM: (Today and Tonight)
Issued at 339 AM CDT Thu May 7 2015

Short-range guidance has been consistently spitting out some sunrise
surprise showers for the past few runs.  The RAP might be a little
overdone as it looks like it`s trying to break pieces of the MCV
currently over Oklahoma off and spread them northeast across the
area.  That being said, radar is picking up some very light echos
developing over the eastern Ozarks at this the possibility
for isolated showers does seem to be increasing this morning.

Aside from any morning showers, expect most of the morning and early
afternoon to be dry.  Should see highs today similar to if not a bit
warmer than Wednesday.  The MCV should lift up into the area and
provide a lifting mechanism later this afternoon.  Additionally,
the cold front now over western Nebraska/Kansas will drift into
western/northwestern Missouri by late this afternoon providing an
additional focusing mechanism.  Think likely PoPs across central and
northeast Missouri into west central Illinois look good with chance
PoPs further to the southeast still look good for the afternoon into
early evening.  PoPs for the rest of the night are less certain
though, and short-range guidance seems to be having as much trouble
as I am figuring out how to handle the situation.  MOS guidance
ranges from low chance to categorical across the area.  GFS and NAM
do show a weak to moderate low level jet setting up during the
evening, with a few waves of moisture convergence in the warm sector
ahead of the front.  Baroclinicity is weak, but present, so I cannot
rule out scattered to possibly numerous showers and
thunderstorms...particularly closer to the front in central and
northeast Missouri.


.LONG TERM:  (Friday through Wednesday)
Issued at 410 AM CDT Thu May 7 2015

Southwest flow aloft will continue to try to bring deeper moisture
back to the Mississippi Valley Friday into the weekend.  It`s
difficult to really pick out a time when thunderstorms are more or
less likely for Friday through Sunday as the foci for precipitation
will likely be fast-moving shortwaves moving over the area in the
southwest flow aloft, as well as low level boundaries from
convection.  Models have the synoptic front generally draped across
northern Missouri...possibly dipping down as far south as the
Missouri river at times as it is forced south by convection.  Have
some flavor of 40-70% PoPs across the area for Friday through
Saturday night with the higher end PoPs closer to the synoptic
front.  Guidance has the high amplitude closed wave finally opening
up and moving int the Great Plains on Sunday with the resulting
surface low moving northeast from Kansas through Iowa into the Great
Lakes Sunday night through Monday.  Resulting cold front should
sweep through the forecast area late Sunday night into early Monday
morning.  Cooler and drier air will bring an end to the rain chances
by most likely by Monday afternoon.  Above normal temperatures will
continue ahead of the FROPA on Monday with highs mainly in the 80s
and lows in the mid 60s.  Medium range guidance drops temperatures
back below normal for Tuesday and Wednesday showing highs mainly 65
to 70 and lows mainly in the upper 40s and low 50s.



.AVIATION:  (For the 06z TAFs through 06z Thursday Night)
Issued at 1053 PM CDT Wed May 6 2015

Just mid-high level cloudiness late tonight. Diurnal cumulus clouds
will develop again late Thursday morning and afternoon with
scattered showers and storms expected as an upper level
disturbance moves through the area with a moist and unstable
atmosphere. Will include VCTS for the taf sites for Thursday
afternoon into the evening. S-sely surface winds late tonight,
then gusty sly winds on Thursday.

Specifics for KSTL: Just some mid-high level clouds late tonight,
then diurnal cumulus clouds will develop late Thursday morning and
afternoon with isolated to scattered showers/storms for late
Thursday afternoon and evening. S-sely surface wind late tonight,
becoming strong and gusty again from a sly direction on Thursday.
The surface wind will weaken Thursday night.



Saint Louis     86  68  84  68 /  30  50  70  40
Quincy          83  65  79  62 /  60  60  70  50
Columbia        82  65  78  64 /  60  60  70  50
Jefferson City  84  65  80  65 /  60  60  70  50
Salem           85  66  84  67 /  20  20  50  50
Farmington      84  65  81  65 /  30  50  60  40




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