Scientific Forecaster Discussion
fxus64 klix 162100
Area forecast discussion
National Weather Service New Orleans la
400 PM CDT sun Jun 16 2019
latest surface analysis showed a 1017mb over Georgia, North
Florida, and northeast Gulf. Southeast flow was present over the
forecast area with dewpoint readings in the upper 60s to mid 70s.
Precipitable water values on the planer view around 1.5 inches
from central Mississippi to southwest Louisiana and 1.7 to 1.8
inches from east central Mississippi to Mississippi coast to
Mississippi Delta. Upper air analysis at 500mb the Atlantic ridge
over southeast U.S. And vigorous short wave over western Oklahoma
and another northeast Texas. In addition, 500 mb temps were around
-8 to -9c. Mid layer instability was present to support isolated to
scattered convection over the region this afternoon.
Surface high/ridge will remain in about the same general
orientation through early in the week. The daily changes in the
forecast will be mainly due to shortwave features in the mid to
upper levels moving across the Southern Plains into the lower
Mississippi Valley. A short wave near the Texas/Louisiana border
has provided enough focus for convection across the central
Louisiana. Surface heating and mid layer instability is sufficient
for a few storms to pulse up to strong to briefly near severe
limits with the main threat being damaging winds. A few showers
and thunderstorms may linger into the evening hours, mainly well
inland from the coast, otherwise most of tonight should be dry in
most locations with warm lows in the 70s.
The main short wave over western Oklahoma will track east across
the mid south Monday and Monday night. An associated trough will
track across the west Louisiana Monday morning and southeast
Louisiana and Mississippi Monday afternoon and Monday evening. The
trough axis will pool moisture and precipitable water will
increase to near 2 inches or slightly higher in the afternoon, so
have maintained the higher/likely chances for showers and
thunderstorms from inland south Mississippi into inland southeast
Louisiana where a convective complex could move through the
region. Some stronger storms with gusty winds and heavy downpours
are likely. The stronger shortwave trough should move through
early Tuesday. Residual moisture will linger and additional minor
shortwaves may move through in west-northwest flow and interact
with moisture. Ergo, will maintain a good chance of convection
over the region Tuesday and Wednesday. Can not rule out gusty
winds and heavy downpours will again be possible on Tuesday.
Temperatures should be at least a degree or two cooler for the
highs on Monday and Tuesday with the increase in convection.
Progressive westerly flow aloft will maintain a track for low
amplitude shortwave troughs to move west to east across the
central Gulf Coast Wednesday into Thursday with the southern
extent of some convective complexes possible moving through at
least the northern portion of the forecast area. Precipitable
water values are not forecast as high as Monday and rain chances
will be slightly lower Wednesday through the end of the week. Some
stronger storms with gusty winds may occur due to the stronger
westerly winds in the mid levels. A subtropical ridge should then
expand out of the tropical Atlantic into the Gulf of Mexico and
central to eastern Gulf Coast Friday and Saturday, so a drier and
warmer pattern is likely to return. 18
Aviation... VFR conditions will prevail through most of the period
for all terminals. Light south winds expected expect higher in and
around any isolated storms this afternoon and evening. Prob30 for
all terminals in the afternoon and evening hours as isolated
summertime type convection is possible this afternoon and early
Southerly flow will continue through the entire forecast period as
surface high pressure sits of the Atlantic southeastern coast.
Showers and thunderstorms expected to increase in coverage on Monday
and Tuesday while synoptic winds will decrease. Southerly winds
expected to increase late week as gradient tightens and surface high
builds westward into the northeastern Gulf. Chances of showers and
storms will decrease by the end of the week.
dss code: blue.
Activities: flood warnings continue along the Mississippi.
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; marginal risk severe or excessive rain.
Yellow = heightened impacts with short-fused watch, warning or
advisory issuances; radar support for slight risk severe or
Orange = high impacts; enhanced risk severe; nearby tropical
events; hazmat or other large episodes.
Red = full engagement for moderate to high risk of severe and/or
excessive rain; direct tropical threats; events of National
Preliminary point temps/pops...
mcb 70 89 71 88 / 20 60 10 70
btr 73 88 73 88 / 10 60 10 70
asd 73 89 73 89 / 10 60 20 70
msy 76 89 76 89 / 10 60 10 70
gpt 75 87 75 87 / 10 50 20 60
pql 72 89 72 89 / 10 50 10 60