Area Forecast Discussion
Issued by NWS St. Louis, MO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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 170811

311 AM CDT Thu Apr 17 2014

.SHORT TERM:  (Through Tonight)
Issued at 300 AM CDT Thu Apr 17 2014

A weak cold front will move into the area today and could serve as
the focus for scattered light rain showers during the afternoon
and evening. Convergence along the front is not very impressive
and the low levels are somewhat dry, but the combination of
increasing large scale ascent ahead of an approaching vort max
along with the presence of a surface boundary merits slight chance
to chance PoPs.


.LONG TERM:  (Tomorrow through Wednesday)
Issued at 300 AM CDT Thu Apr 17 2014

For the last 4 nights in a row, no two consecutive 00z runs of the
ECMWF/GFS/GEM have had the same solution for upcoming frontal
systems, and there has also been a fair amount of variability
between models regarding the location of important features such as
upper vorticity maxima and surface boundaries. The latest runs keep
a strong vort max and its surface low up near the US/Canada border
on Fri night and Sat, therefore precipitation is no longer expected
with this system across the LSX CWA. The dominant feature for
Fri-Sat now appears to be ridging. Winds should eventually turn
southerly, bringing warmer air into the region for Sat and
reinforcing a baroclinic zone extending from the US/Canada system
as it starts to occlude. A broad trough moving through the desert
southwest could bring precipitation to the area on Sun/Mon. Chance
PoPs remain an acceptable compromise in light of the model
uncertainty. Confidence remains low in the forecast for this
weekend and beyond.



.AVIATION:  (For the 06z TAFs through 06z Thursday Night)
Issued at 1149 PM CDT Wed Apr 16 2014

Anticipate conditions will remain VFR despite a frontal passage
tomorrow morning. South wind will swing around to the northwest
with the front and then relax, becoming light and variable
Thursday evening. The lack of low level moisture keeps the
forecast dry at this time.

Specifics for KSTL:

VFR conditions with a south wind becoming southwest tomorrow
morning and then shifting to the northwest with the cold front
early tomorrow afternoon. Wind to become light and variable
tomorrow evening. VFR clouds possible behind the front, but
moisture looks limited, with a dry forecast continuing.





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