Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Huntsville Alabama
249 PM CDT Tuesday Jul 22 2014
isolated showers and storms continue to develop across northern
Alabama and southern middle Tennessee. Scattered activity can be
seen on area radars primarily in northeastern Mississippi and south
of our southeastern counties. So far mostly cloudy conditions have
been prevalent enough to limit daytime heating and retard shower and
storm development overall.
Expect coverage to become more scattered before they diminish during
the evening hours. Models continue to move the low near Mobile
further southwest overnight. However...a weak area of convergence
will remain in place over northern Alabama...although the exact
orientation of this boundary is hard to dechiper from the models.
Models do seem to agree that a more pronounced shortwave pushes
southeast from Missouri and Indiana into the Tennessee Valley on
Wednesday...strengthening the convergence associated with this
boundary. This should produce more showers and thunderstorms than we
have seen today...but may still remain scattered in coverage. With
precipitable water values around 2 inches...heavy rainfall will be the main threat
with any storms that develop.
Quickly on the heels of the shortwave...the models push a weak cold
front into the Tennessee Valley overnight Wednesday and into
northern Alabama Thursday morning. Models continue to show this front
pushing south of Cullman...Marshall...and DeKalb counties by Thursday
evening as it weakens even more. Again heavy rainfall will be the
main threat with any storms that develop.
Models disagree concerning keeping an isolated pop in the forecast
on Friday. At this point due to the dry air expected to push in
behind the front...taking out isolated pop. This dry trend will
continue into Saturday as even drier air pushes south into the area.
A more active pattern returns Sunday through Monday. Storms with
this system could have stronger 850 mb (30 kts) and 500 mb (40 kts)
wind fields and decent cape values. This could enhance the
possibility for some severe storm development Sunday night or Monday.
Temperatures were lowered significantly on Tuesday behind the front.
/issued 1203 PM CDT Tuesday Jul 22 2014/
for 18z tafs...weak upper low over southern MS/Alabama will continue to slowly
move west today. Thinking that there will be enough lift with the
upper low (along with daytime heating) to kick off scattered rain showers/thunderstorms and rain
across the taf sites this aftn/evening. Time sections were also
showing enough moisture for more scattered rain showers/thunderstorms and rain on Wednesday (by middle
mrng/aftn). Except for MVFR conditions in thunderstorms and rain...mainly VFR
conditions are expected through the period.
Preliminary point temps/pops...
Huntsville 70 90 71 86 / 20 40 40 60
Shoals 69 92 70 87 / 20 40 50 60
Vinemont 69 89 69 85 / 20 40 40 60
Fayetteville 68 89 69 83 / 20 40 60 30
Albertville 69 87 69 85 / 20 40 40 60
Fort Payne 69 88 67 85 / 20 40 40 60
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