Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
FXUS64 KLIX 271302
Area Forecast Discussion
National Weather Service New Orleans LA
802 AM CDT Mon Mar 27 2017
The atmosphere is stable for our area today thanks to a strong cap
near 700 mb. Otherwise though, there are several parameters
indicative of the severe storm threat today well to the north
across Mississippi into Tennessee. Very little fog this morning
since conditions remained breezy overnight. Onshore flow is
strong, 20 kts at just 1000 ft. Winds become more westerly with
height. Another warm and humid day is expected.
.PREV DISCUSSION... /issued 331 AM CDT Mon Mar 27 2017/
A mid/upper level short wave trough will traverse the mid and
lower Mississippi Valley today bringing a threat of isolated to
scattered convection to the forecast area. The best dynamics and
support for convection will reside to the north of the local area
with this system. As a result, the best chance for showers and
thunderstorms will be across our southwest Mississippi counties
and the adjacent parishes of southeast Louisiana with decreasing
chances farther to the south. Even across our northern areas, POPs
will be kept in the 30 to 40 percent range. An isolated strong
storm or two cannot be ruled out across the far northern reaches
of the area where SPC has outlooked a marginal risk for severe
weather. The main threats in these areas would be damaging winds
and large hail.
A few showers and storms could linger into the evening hours
across the far northern sections of the forecast area. Otherwise,
quiet conditions will prevail tonight with some fog development
expected after midnight that will persist through early Tuesday
morning. Tuesday should be warm and mostly dry with upper level
ridging over the Gulf Coast states. Models continue to indicate
the possibility of some convection across the area during the day
Tuesday, although any chance should be rather small. Plan to
confine the mention of any chance for convection across the
northern most sections of the P/CWA which will be closer to a
stalled out front to our north. 11
A warm but occasionally unsettled period is on tap for the area
as a couple of potentially strong systems affect the region during
the period. Wednesday should be dry as upper level ridging over
the southeast conus shifts to the east. The threat for convection
will begin to increase from the west Wednesday night and continue
through Thursday night as a potent upper low/trough moving out of
the Southern Plains Wednesday translates eastward across the lower
and mid Mississippi Valley region Thursday and Thursday night.
This system will have the potential to produce some strong to
severe thunderstorms across the area along with locally heavy
rainfall Thursday and Thursday night before shifting off to the
A quiet period will commence on Friday and continue into Saturday
as upper level ridging builds back over the south ahead of yet
another strong system that will impact our weather for the latter
half of the weekend and into the beginning of the following work
week. There are still some differences between the models with the
strength, evolution and timing of this system, but at this time it
appears that the path of this vigorous system will be farther
south than its predecessor and will move across the lower
Mississippi Valley during the aforementioned time period. This
system is still seven to eight days out, but there appears to be
some potential for a severe weather and possibly heavy rainfall
threat with it. 11
Most terminals reporting ceilings in the IFR or lower end of MVFR,
although several sites have occasionally gone scattered. Expect the
IFR/MVFR ceilings to predominate during the rest of the night and
through mid morning. If winds drop off, could also see visibilities
fall to near 3SM. Will continue mention of potential TSRA at KMCB
and KBTR during the day, although will need to use VCTS as POP/areal
coverage not high enough to carry prevailing. Will also mention of
VCSH at KGPT. Outside of convection, anticipate late morning and
afternoon to have VFR conditions. Once again, expect low cloud
development during the overnight period tonight with MVFR to IFR
ceilings developing, primarily after 06z Tuesday. 35
Winds over coastal waters today will be near the 15 knot threshold
for starting to consider Small Craft Exercise Caution headlines.
For now, will hold off and day shift can issue if they get up into
the 17-18 knot range. More likely to need headlines Wednesday
into Friday morning, then again late Saturday. 35
DSS code: Green.
Activities: Assessing convective threats for this week.
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 82 63 83 62 / 40 20 20 10
BTR 83 63 84 63 / 30 10 10 10
ASD 81 63 82 63 / 20 10 10 10
MSY 82 66 81 66 / 20 10 10 10
GPT 79 66 79 65 / 20 10 10 10
PQL 80 63 81 62 / 20 10 10 10