831 
FXUS64 KLIX 201312
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
812 AM CDT Fri Oct 20 2017

...SOUNDING DISCUSSION...
The sounding is still stable and overall dry this morning. There
is a 10 F radiation inversion in the first 1000 ft and an elevated
inversion above at 800 mb. Stronger easterly flow will result in
more moisture return today and spot showers, mainly near the 
south Louisiana coast. Winds are at 20 kts already just above the 
surface.

Krautmann


&&


.PREV DISCUSSION... /issued 333 AM CDT Fri Oct 20 2017/ 

SYNOPSIS...

Surface high currently centered over the Appalachian Mountains.
Low pressure was centered over the Canadian Rockies with a cold
front down the lee side of the Rockies. An inverted surface trough
was located over the western Gulf of Mexico. Upper ridging was
currently centered over the local area. There was a line of 
thunderstorms associated with the trough over the western Gulf, 
but those are moving toward the Texas coast. Temperatures are 
quite a bit milder this morning with most locations seeing 
temperatures in the 60s at 3 am. 

SHORT TERM...

Upper ridge and surface high will continue to move eastward today
and Saturday, as the frontal system to the west moves out of the
Rockies. This will allow surface winds to gain more of a
southeasterly component, increasing moisture across the area.
Current precipitable water values in the 0.7 to 0.8 inch range
will effectively double by Saturday afternoon. An easterly wave
moving around the periphery of the upper ridge will bring chances
for showers to far southern portions of the area today and 
tonight. As the cold front and upper trough approach from the west
on Saturday, there will be a better potential for showers and 
thunderstorms across the area. Best forcing will remain northwest
of the area. Shear is rather limited, so, while a few storms could
become strong, most should stay below severe limits.

On Sunday, the upper trough and a surface prefrontal trough will 
approach the area. CAPEs around 1500, Lifted Indices of -6 and 
lapse rates around 6.5 should be conducive to some strong storms,
but shear will remain weak and wet bulb zero values of nearly
13,000 feet should indicate a low, but not zero, threat of severe
weather. Will carry likely to categorical POPs across the area on
Sunday. The associated cold front looks to move through the local
area overnight Sunday night, possibly as late as after sunrise 
Monday along the Mississippi coast. Could be some lingering rain
patches behind the frontal passage going into Monday. 

Expect much above normal temperatures through the weekend,
especially at night, with lows in the 70s for much of the area
Saturday and Sunday mornings. No major differences in model
guidance numbers prior to Sunday. Will trend a little toward the
cooler guidance for highs on Sunday. 35

 

LONG TERM...

Behind the front, a deep upper trough will cover much of the
eastern half of the country for much of the first half of the work
week. Early showers Monday will be the last substantive chance of
rain until at least next weekend. Cold air will get reinforced
Tuesday, making for a fairly cool middle of the week. Temperatures
will return to near normal levels by Thursday or Friday. 35

AVIATION...

VFR category conditions are generally expected at each of the 
terminals through the TAF forecast period. There will be small 
chances for convection to impact KHUM this afternoon and KHUM, KMSY 
and KNEW tonight. Patchy light fog may also affect the more fog 
prone TAF sites late tonight and early Saturday morning. 11

MARINE...

Moderate to occasionally strong easterly flow will continue across 
the coastal waters through Saturday. This will result in exercise 
caution conditions that may flirt with small craft advisory criteria 
at times, at least over the open Gulf waters. The winds will ease 
and shift to the southeast Sunday in advance of a cold front that 
will move through the coastal waters Sunday night into early Monday. 
Moderate to strong offshore flow will develop in the wake of this 
front that will persist into the middle of the next work week. 11

DECISION SUPPORT...

DSS code: Green.
Deployed: None.
Activation: None.
Activities: None.
   
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  84  65  84  70 /   0  10  40  30 
BTR  85  69  85  72 /   0  10  60  40 
ASD  84  69  84  73 /  10  20  50  30 
MSY  84  72  84  74 /  10  30  50  30 
GPT  83  70  83  73 /   0  10  30  30 
PQL  84  68  83  71 /   0  10  30  30 

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...None.
MS...None.
GM...None.
&&

$$