Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service St Louis MO
310 am CDT Sat may 30 2015

Short term: (through monday)
issued at 309 am CDT Sat may 30 2015

Cold front stretching from Wisconsin to Kansas will continue to
press southeast today as one last potent shortwave rotates northeast
across the region. Precipitable waters will approach 2 inches ahead of the cold
front, which means showers and thunderstorms will continue to be
very efficient rain producers. Adjusted and extended the Flash Flood
Watch to align with areas that are expected to see the greatest
amounts of rain and convection through this evening, generally the
southeastern half of the County Warning Area.

Still believe measurable preciptiation will shut down quickly this
evening from west to east with only some lingering drizzle and
patchy fog possible overnight. Temperatures will certainly be cooler
behind this front with lows in the 50s and highs only in the 60s on
Sunday and lower 70s on Monday.


Long term: (monday night through friday)
issued at 309 am CDT Sat may 30 2015

Temperatures will continue to warm up to near normal levels for
the first part of the work week as the surface ridge moves east
and an upper level ridge tries to build across the plains into the
Mississippi Valley. While the flow aloft remains northwesterly,
low level flow becomes southerly by Thursday which should allow
some moisture to return to the area. Additionally, the 850mb
thermal ridge builds up across the area Thursday into Friday which
looks to allow temperatures to warm above normal for the end of
the week. Medium range models show a couple of shortwaves trying
to move around the periphery of the upper level ridge from the
middle of the week through Friday, spitting out some light quantitative precipitation forecast as
they move across the area. Can't rule out scattered thunderstorms
as this occurs due to the increasing moisture from southerly flow
in the low levels, so slight chance to low chance pops provided by
ensemble guidance looks pretty reasonable.



Aviation: (for the 06z tafs through 06z Saturday night)
issued at 1057 PM CDT Fri may 29 2015

Showers and storms will continue late tonight as the large area
of showers and thunderstorms across south central MO ahead or
northeast of an upper level disturbance and associated surface low
shifts northeastward through the taf sites late tonight. A strong
southerly low level jet will also lead to redevelopment of
convection across our area late tonight. The MOS cloud guidance is
consistent in dropping the cloud ceilings late tonight and
Saturday morning down to around 1000-1500 feet. Prevailing surface
winds will be mainly sly for most of late tonight, then shift to
a nwly direction Saturday morning as the surface low moves
northeastward through southeastern MO and as a cold front now
entering northwest MO drops southeastward through our area. The
showers and thunderstorms will taper off from northwest to
southeast on Saturday.

Specifics for kstl: showers and storms will continue late tonight
as a large area of showers and storms across south central MO
moves northeastward into stl late tonight lingering into at least
Saturday morning. The cloud ceiling will drop late tonight and
Saturday morning down to around 1000-1500 feet. Prevailing surface
winds will be S-sely late tonight, although there will be some
variability near thunderstorms. The surface wind will become nwly
Saturday morning. The showers and storms should taper off Saturday
afternoon and evening after passage of the surface low and cold
front, but cloud ceilings will remain low.



Preliminary point temperatures/pops:
Saint Louis 74 54 66 56 / 90 50 5 5
Quincy 69 49 65 51 / 80 20 0 0
Columbia 69 52 67 53 / 70 20 5 5
Jefferson City 70 53 68 54 / 70 20 5 5
Salem 78 56 67 55 / 90 70 10 5
Farmington 75 51 66 54 / 80 40 10 5


Lsx watches/warnings/advisories:
MO...Flash Flood Watch through this evening for Crawford MO-Franklin
MO-Gasconade MO-Iron MO-Jefferson MO-Lincoln MO-Madison MO-
Montgomery MO-Reynolds MO-St. Charles MO-St. Francois MO-
St. Louis city MO-St. Louis MO-Ste. Genevieve MO-Warren MO-
Washington MO.

Illinois...Flash Flood Watch through this evening for Bond Illinois-Calhoun Illinois-
Clinton Illinois-Fayette Illinois-Greene Illinois-Jersey Illinois-Macoupin Illinois-
Madison Illinois-Marion Illinois-Monroe Illinois-Montgomery Illinois-Randolph Illinois-
St. Clair Illinois-Washington Illinois.



Weather forecast office lsx

National Weather Service Glossary of Abbreviations