Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 270905
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
405 AM CDT Mon Apr 27 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 328 AM CDT Mon Apr 27 2015

Another quiet spring day is expected today with highs in the 60s
and occasional mid/high clouds across the area.

Kanofsky

.LONG TERM:  (Tonight through Sunday)
Issued at 328 AM CDT Mon Apr 27 2015

There have been few substantial changes in the model guidance and
therefore little change in thinking since the previous forecast.
A slow-moving cutoff low pressure system was located near the
TX/NM border at 08z, and this system will slowly move eastward
over the next few days. Precipitation with this system is expected
to remain south of the CWA, although there is an outside chance
that the extreme southern part of the CWA could see a few rain
showers on Tue.

The latest ECMWF and GEM runs no longer depict a closed H5 low
dropping southeast out of Canada and retrograding during the
middle of the week, instead showing more of a shear axis passing
over the region during that time. The latest GFS run does show a
deep closed low developing over the Great Lakes and dropping
southward, but its position with this feature is much farther east
than what the ECMWF/GEM were showing 24hrs ago. Despite this
variability, the overall trend in the models remains the same: the
slow-moving cutoff low eventually interacts with another vort max
to form a deep trough over the eastern one-third of the CONUS
towards the middle and end of the week. Expect some increased
cloudiness with the passing shear axis, but there are no strong
signals for widespread rain during the week.

In the absence of large scale air mass exchanges, temperatures
should be governed by diurnal heating, the effects of cloud cover,
and a consistent northerly component to the low-level flow which
is forecast to remain in place through the end of the work week.
Expect gradually warming temperatures through the week with highs
reaching the 70s by Fri.

Kanofsky

&&

.AVIATION:  (For the 06z TAFs through 06z Monday Night)
Issued at 1138 PM CDT Sun Apr 26 2015

A large area of high pressure extending out of sthrn Canada will
dominate thru the prd producing VFR conditions and a persistent
N/NE flow. There will be overnight cirrus originating from
convection across the sthrn Plains and some diurnal cu tomorrow.

Specifics for KSTL:

VFR conditions thru the prd with N/NE winds aob 12kts with diurnal cu.

2%

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX





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