Area Forecast Discussion
Issued by NWS St. Louis, MO

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

FXUS63 KLSX 060924

324 AM CST Fri Mar 6 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 313 AM CST Fri Mar 6 2015

Some mid level cloudiness across the western half of IA ahead of a
northwest flow shortwave and in a region of low-mid level warm air
advection will move eastward through parts of northeast MO and west
central IL this morning.  Warmer temperatures can be expected this
afternoon as the surface ridge extending from northeastern AR
northeast through southern IL moves southeastward and the surface
wind becomes south-southwesterly across our forecast area.  The
models shift the zero degree C 850 mb isotherm eastward to the
Mississippi River by 00z Saturday.  Went closer to the warmer GFS
MOS guidance for high temperatures today, particularly in areas
without snow cover from central MO eastward through the St Louis
metro area.


.LONG TERM:  (Tonight through Thursday)
Issued at 313 AM CST Fri Mar 6 2015

The trend to more typical early March temperatures should
continue to be the primary forecast trend as we head into the
weekend and early next week. As UA flow regime over all but the
extreme southern CONUS takes on a west-northwest look, the cold
air that has been locked over the eastern half of the country for
the past few weeks will begin retreating into southeast Canada and
New England, allowing a more moderate AMS to spread from the
Plains to the mid- Mississippi Valley. Shortwaves embedded in the
west- northwest flow will make several attempts to bring some
cooler air our way, but with the pattern blocking any strong
southward intrusion of cold air these cool downs should be
relatively minor.

Believe that the warmup and strong sunshine that occurs today will
be a "snow eater" in many parts of the CWA, so by Saturday any
impacts of existing snow cover on temperatures will likely be
fairly minimal and confined to our far SE counties. With a
westerly wind component advecting temperatures from the snow-free
areas of western MO and lots of sunshine, forecast highs for
Saturday will continue to lean towards the warm side of guidance.
I`ve placed the warmest temps (55-60) along the thermal ridge
progged along and just south of the I70 corridor in Missouri, with
highs in the upper 40s and lower 50s elsewhere.

A bit of cooler air oozing into the region on Sunday along with
additional high cloudiness should keep highs near their average
early March levels, with similar readings expected on Monday.


00z guidance continues to indicate a pronouced (and for most, a
welcomed) warmup in the offing for the mid-Mississippi Valley
heading into the middle of next week as heights build across the
central U.S.  Initial surge of warmth on Tuesday should push most
areas west of the Mississippi to around the 60 degree mark, with
highs in the 60s over most of the region by Wednesday and

Precipitation chances should remain quite low through the middle
of next week. However, there appears to be some agreement in
medium range solutions that remnants of southwest U.S. upper level
low will drift our way by the end of the period, and have added
some low PoPs to southeast sections of the FA for Thursday and
Thursday night.



.AVIATION:  (For the 06z TAFs through 06z Friday Night)
Issued at 1124 PM CST Thu Mar 5 2015

VFR fcst thru the prd. Winds have become SErly this evng on the
back side of the sfc ridge. Winds in the lowest few thousand feet
are expected to approach 35-40 kts towards 12Z but should remain
below LLWS criteria. A band of mid clouds is expected to signify
the passage of an upper lvl disturbance Fri mrng. Srly flow will
continue thru the prd with gusts near 20 kts possible tomorrow
late mrng/aftn.

Specifics for KSTL:

VFR fcst thru the prd with sthrly flow near 12kts drng the late





WFO LSX is the U.S. government's official web portal to all federal, state and local government web resources and services.