Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA

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FXUS64 KLIX 242055

Area Forecast Discussion
National Weather Service New Orleans LA
355 PM CDT Tue Apr 24 2018

Latest surface analysis showed a 1008mb low over South Carolina
with a trough axis extending southwest from the low to coastal
Mississippi to Lake Pontchartrain. Upper air analysis revealed a
low over central Tennessee and a positively tilted trough axis
North Dakota to southeast Wyoming. 18


Surface pressure gradient will continue to relax tonight.
Temperatures overnight will fall and atmosphere at the surface
will become saturated tonight after midnight, mainly across the
northern zones. Therefore, we maintain the patchy fog wording
across northern zones around sunrise Wednesday morning.

Upper level low will continue to push toward the Eastern Seaboard
through Wednesday. The trough out west will dive southeast and
deepen over the Central Plains Wednesday. This system will bring
its own moisture with precipitable water values up to 1.4 inches
early Thursday morning. The trough will reach the Lower
Mississippi Valley Thursday morning becoming neutrally tilted
Thursday morning and becoming negatively tilted over Alabama
Thursday afternoon, east of our forecast area. This is a cold
core system with the core of -21F well north but -16F across
southwest Mississippi Thursday morning. This will offset the lack
of a moist southeast flow. The cooler temps at 5h will increase
instability across the north zones for Thursday. Will increase
isolated to scattered thunder due to the frontal focus favorable
lapse rate mainly across the north zones late Wednesday night and
early Thursday.

A secondary wave is expected Friday morning through the afternoon.
Precipitable water values are expected to fall to a half inch
after Thursday`s storm system and increase up to 0.8 inch along
this second wave. This is a another cold core system sweeping
across the north and east zones. Have inserted thunder as steep
lapse rates steep thunderstorms but lack of moisture will only
yield isolated coverage. In addition, -16F to -20F up across
Southwest Mississippi and Southern Mississippi including coastal
Mississippi may yield a one or two storms will small hail on
Friday. Conditions will improve Friday night with a pleasant dry
weekend expected with seasonal temperatures.


Offshore flow pattern continues with surface high pressure centered
northwest of the area. The pressure gradient remains strong enough
to hold winds in the 10 to 15 knot range. Actual wind direction will
vary from west today to north tomorrow as the ridge slides east. A
relatively weak cold front slide through Thursday morning as a weak
upper trough tracks across the southeast. A surge of drier air
behind this front could push winds back to around 15 knots Thursday
morning and early afternoon. Very progressive upper level pattern
will bring yet another frontal boundary through the coastal waters
Friday. This will push winds back to 15 to 20 knots over the open
Gulf waters for Friday evening through early Saturday. Surface high
pressure will track from west to east across the southeastern CONUS
this weekend. This will cause winds to rotate around from NW to SE.


Visible satellite shows scattered CU field moving across the region.
These clouds will erode this evening with loss of daytime heating.
VFR conditions will generally prevail across the area through the
forecast period. There`s a short window around sunrise when patchy
light/moderate fog could bring visibility down to IFR. MCB and HUM
are the more likely candidates if anyone observes fog.



DSS code: Blue.
Deployed: None.
Activation: None.
Activities: Sandhill Crane NWR Outreach Support
            New Orleans Navy Week Support

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
         excessive rain.
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 rainfall; direct tropical threats; Events of
         National Significance.


MCB  54  78  56  73 /   0  10  40  50
BTR  56  80  57  74 /   0  10  40  50
ASD  55  79  58  76 /   0   0  20  50
MSY  61  79  61  75 /   0   0  10  50
GPT  59  79  62  76 /   0   0  10  50
PQL  56  79  58  76 /   0   0  10  30



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