Scientific Forecaster Discussion
fxus64 klix 220900
Area forecast discussion
National Weather Service New Orleans la
400 am CDT Sat Jul 22 2017
upper low will keep the area under enough sh/ts and cloud cover
to keep heat index values low enough to keep the oppressive heat
down. But this will change as we approach mid week. The stacked
high from the sfc up to 700mb will begin to take shape today over
the Florida Straits and move into the Gulf tonight and Sunday.
This feature can be observed best at the 850mb level.
A strong short wave, over southern Canada, embedded in the larger
upper trough is moving southeast this morning. This feature will
cause the upper trough over the Midwest to sharpen and dig
southeast developing a weak sfc trough axis oriented NW-se
adjacent to our area possibly as early as Monday. The Gulf sfc
high will settle up against this weak stationary trough causing a
slightly tighter pressure gradient to exist helping to elevate
wind speeds just a bit while producing daily sh/ts over locations
just northeast of the area. A few of these are expected to
develop into the area as well. This may be enough wind to
ventilate the column keeping heat index values from getting out of
control. But the battle grounds between teh high and the trough
will set up a fairly steep precip and temp gradient starting
Monday or Tuesday and lasting through the week. If this boundary
meanders into the area one or two days, the potential for a severe
thunderstorm will be heightened. With heating as it is, strong or
even a severe thunderstorm could occur any given day. The main
hazards expected with anything capable of developing into a severe
thunderstorm would be very heavy rain, wind, hail and plenty of
with the exception of one or two locations observing br or fog this
morning, VFR conditions outside sh/ts should be the rule through
Sunday morning. An early start to the sh/ts activity will show
today and activity should develop and decay throughout the day.
Some of the stronger thunderstorms could produce winds up to 40mph
a sfc high will move into the northern Gulf and settle up against
a weak stationary trough causing a slightly tighter pressure
gradient to exist helping to elevate wind speeds to 10-15kt. This
should remain through much of the week. An abundance of sh/ts
activity is expected but will be found mostly during morning
hours. Some of these could become strong with winds up to 40kt
dss code: green.
Activities: monitoring convective trends.
Decision support services (dss) code legend
green = no weather impacts that require action.
Blue = long-fused watch, warning, or advisory in effect or
high visibility event.
Yellow = heightened impacts with short-fused watch, warning or
advisory issuances; radar support.
Orange = high impacts; slight to moderate risk severe; nearby tropical
events; hazmat or other large episodes.
Red = full engagement for moderate risk of severe and/or
direct tropical threats; events of National significance.
Preliminary point temps/pops...
mcb 90 73 90 74 / 40 20 60 30
btr 90 74 90 76 / 50 20 60 20
asd 91 76 91 77 / 40 20 60 30
msy 90 77 89 78 / 40 20 60 20
gpt 89 78 88 78 / 40 20 50 30
pql 90 76 89 77 / 40 30 50 30