Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

FXUS64 KLIX 222059

Area Forecast Discussion
National Weather Service New Orleans LA
359 PM CDT Tue Oct 22 2019

.DISCUSSION...After a rather nasty day yesterday it was far more 
pleasant today. Very dry air has pushed into the region and cold air 
has been advecting in through the day. Only clouds have been high 
clouds streaming in across the region from the southwest. 

For the next 48 hours things will remain fairly quiet and on the 
cool side. High pressure at the sfc is building in and should set up 
right over the region tonight. With light winds at the sfc and dry 
cool air in place conditions do look good for a favorable rad 
cooling night and some of the coldest morning lows we have seen 
since mid-late April across the region. Most of the area will drop 
below 50 degrees for a morning low tomorrow and the last time that 
occurred was either on April 22nd or 27th for much of the area. 
There are 2 things that could hurt rad cooling potential tonight. 
First is winds just off the deck (around h925) actually remain on 
the strong side and this would promote mixing. These winds will 
remain strongest over coastal MS through the night but do lighten up 
over southeast LA and southwestern MS after 6z. The other minor 
issue is high clouds streaming over the region. These 2 features may 
keep temps from fully bottoming out which if they could places like 
ASD and MCB could touch 40. 

We will remain below normal for both highs by 4-6 degrees over much 
of the area tomorrow with another sunny day in store followed by one 
more night of optimal rad cooling conditions. Thursday morning lows 
will not be as cold as tomorrow morning as we will begin to slowly 
moderate with the sfc low lifting to the northeast. 

Main forecast concern is the system expected to impact the region 
Thursday night and possibly through the weekend. There is a lot of 
differences in specific model soln but overall the rain chances look 
rather favorable through at least Friday night. A strong s/w will 
dive south-southeast out of wrn Canada and dig across the 
continental divide and the Plains. How far south and west this s/w 
digs will be key for how prolonged the rain event will be. Either 
way we begin to slowly recover with moisture increasing Thursday. 
Increasing southwest flow aloft will lead to better support aloft. 
This will also begin to induce some weak cyclogenesis over the 
southwestern Gulf. Increasing flow aloft and increasing isentropic 
lift should allow rain to begin overnight Thursday expanding through 
the morning with a shield of rain and embedded thunderstorms over 
the region ahead of the approaching cold front Friday. Main 
disturbance should lift out to the northeast Sat with drier air 
finally moving back in Sunday. 

As for threat of strong to severe weather, the potential seems 
fairly low at this time. We really never fully recover from our 
front that just moved through and when we have the best instability 
in place forcing is not that strong and much of the lift will be 
driven by isentropic lift along with broad diffluence aloft. /CAB/


.MARINE...Small craft advisory conditions will continue through the 
night for the open waters. Weak cold air advection and strong winds 
just off the sfc should continue to lead to windy conditions tonight 
but just before sunrise conditions should begin to improve. The next 
cold front will approach this weekend with a weak sfc low expected 
to develop over the southwestern Gulf and move northeast. /CAB/


,AVIATION...VFR conditions will continue through the forecast. /CAB/



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; 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, or direct tropical threats; Events of 
         National Significance.


MCB  42  72  46  72 /   0   0   0  10 
BTR  43  72  50  74 /   0   0   0  20 
ASD  44  73  48  75 /   0   0   0  20 
MSY  53  72  59  75 /   0   0   0  20 
GPT  46  71  51  73 /   0   0   0  20 
PQL  42  72  47  75 /   0   0   0  20 


GM...Small Craft Advisory until 7 AM CDT Wednesday for GMZ536-538-550-

     Small Craft Advisory until 11 PM CDT this evening for GMZ532.

GM...Small Craft Advisory until 7 AM CDT Wednesday for GMZ538-550-552-

National Weather Service Glossary of Abbreviations