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Area Forecast Discussion
National Weather Service New Orleans LA
339 AM CDT Fri Oct 28 2016


Increased negative vorticity advection and subsidence in the mid
and upper levels of the atmosphere will effectively limit cloud
development through the weekend. With an increasingly strong mid-
level cap in place, expect to see dry weather through the period.
A sinking airmass combined with the lack of cloud cover and dry
air will allow for very warm temperatures in the middle to upper
80s each afternoon. Strong radiational cooling during the
overnight hours should push temperatures down into the 50s and
lower 60s each night. Additionally, conditions look conducive for
radiation fog development each night as a surface inversion forms
and decouples the boundary layer flow from the surface. Some of
the fog could turn dense at times.  


Strong ridging throughout the atmospheric column will continue to
dominate through the first half of next week with clear skies, low
POP, and a fairly large diurnal range of 25 to 30 degrees
persisting. Daytime highs will continue to climb into the middle
to upper 80s, and overnight lows should fall into the upper 50s
and lower 60s. Boundary layer winds will remain light enough to
allow the atmosphere to decouple each night resulting in continued
radiation fog formation. As is the case this weekend, the fog
could turn locally dense at times.  

The pattern will begin to shift slightly for Wednesday and
Thursday of next week, as the ridge axis shifts further to the
east. Overall subsidence should diminish, and the cap should
weaken slightly. However, a deep pool of dry air in the mid-levels
should effectively kill any rain potential both days. At most, a
scattered to broken stratocumulus field is expected to form
beneath the mid-level cap. The combination of clear skies, light
boundary layer winds, and high relative humidity in the low levels
will also keep the threat of radiation fog formation in place
during the overnight hours. Temperatures will remain warm, but
should fall back into the lower to middle 80s as subsidence aloft
decreases. These readings are still above seasonal norms for early

Both the GFS and the ECMWF indicate that a front will slide
through the area Thursday night and Friday. Both models show this
front to be moisture starved resulting in continued low rain
chances of around 10 to 15 percent. This system should result in a
wind shift to the north, and also bring in some drier and cooler
air as weak cold air advection takes hold. Overall, temperatures
should finally fall back to more seasonal readings in the upper
70s and lower 80s during the day and the 50s at night.  



Fog is starting to develop in isolated locations this morning. This
should become more widespread by sunrise and include every terminal.
Some ceilings look to be present around sunrise at a few
locations and this may help vis restrictions at those sites. VFR
conditions should resume by 15z today. But fog should develop once
again tonight. This will be shown with prevailing conditions.



Winds will be high enough to raise caution flags for most open gulf
waters today. This will remain through at least tonight but may be
extended into Saturday. Protected waters are not expected to be
impacted by the stronger winds at the moment. But the most southern
bays such as Caminada, Barataria and Terrebonne Bays may have winds
of 15 knots with gusts to 20 at times through this evening. A deep
fetch of 20+ knot winds outside the local waters will provide swell
to add to the wind wave heights through a good part of next week.
Winds should slowly ease toward the end of next week. Advisory
conditions, especially for the outer waters, will be possible over
the next several days as well.



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.


MCB  86  57  87  56 /   0   0   0   0 
BTR  86  59  87  58 /   0   0   0   0 
ASD  84  58  85  57 /   0   0   0   0 
MSY  83  64  84  64 /   0   0   0   0 
GPT  82  61  83  61 /   0   0   0   0 
PQL  84  57  84  57 /   0   0   0   0 





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