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

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FXUS64 KLIX 210840
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
340 AM CDT Sun Apr 21 2019

.SHORT TERM...Quiet day across the region and this will continue for
a few more days. Overnight skies remained clear and and this with
light winds and dry conditions provided great radiational cooling
conditions and by 7z temperatures had already fallen into the mid
40s to mid 50s across the region.

Sunday through Tuesday the weather will continue to be quiet. We
should begin to moderate today with a ridge building in over the
region. This along with a sfc high sliding east over the
northeastern Gulf will lead to LL temps warming today. Highs today
should climb about 2-4 degrees warmer than yesterday and temps will
climb another 2-4 degrees tomorrow. On Tuesday the ridge axis will
slide east of the area. This will begin to put the region under weak
SW flow and should allow clouds to slowly return. Highs will also
range from around 77 to 83 degrees.

Radiational cooling conditions should still be fairly good the next
2 nights as winds will quickly decouple as the sun goes down and
dewpoints will slowly recover over the next 48-60hrs. Lows Monday
morning will be about about 5-8 degrees warmer than what we see this
morning but this will still be around 3-7 degrees below normal. Even
as conditions continue to recover Monday we should see one more
night of slightly below normal temps Tuesday morning but that will
be it. /CAB/

.LONG TERM...Models continue to come into agreement and actually it
is quite remarkable how closely the GFS and ECMWF resemble each
other over our area through 12z Fri. With this confidence is
increasing in the forecast for Thursday and Thursday night.

The main focus of the extended remains the system Thursday. It did
come onshore over the PAC NW last night and with it now being
sampled better it looks like it made a difference as the GFS has
come along towards the ECMWF soln. Our system will dig west of the
Continental Divide today and start to close off. By Monday night it
will have dropped down to the Mexico/US border just north of the
Baja and then begin to slowly work towards the east as the mid level
jet slowly begins to round the base of the low. Wednesday it will
move into TX and approach the Lower MS Valley. This should help
to continue to increase the cloud cover over the region but we
will remain rain free Wednesday still.

This system will finally move into through the Lower MS Valley
Thursday and Thursday night. As it approaches the ARKLATEX region
early Thursday there will likely be an impulse embedded in the flow
to work across the Lower MS Valley. This along with an approaching
cold front should help to spark showers and thunderstorms across the
region during the day. With respect to the severe weather and heavy
rain threat, the potential is still there however the details aren`t
quite as impressive as the past few systems, of course those
systems didn`t quite materialize over our area but did produce
widespread severe weather just outside of the outlook area.
Overall there will be instability to work with, some shear, and
abundant moisture. Forcing will not be an issue so numerous to
widespread showers and thunderstorms with a few strong to severe
storms look favorable. Heavy rain could be a pretty good concern
as well. As mentioned moisture will be abundant with PWs likely
over 1.6" which is easily in the top 10% and not far from the
record high for 12z on the 25th. This will combine with a
favorable jet location providing strong diffluence aloft and an
increasing LL jet leading to rather efficient thunderstorms.

All things point to heavy rain being a pretty good call along with
a few strong to severe storms but as mentioned last night there
is the potential for things not to come together over the area.
Biggest concern continues to be convection developing and becoming
anchored across the Gulf and this would cut us off. As that
happens we could then get dry slotted and we would then struggle
to get much more than moderate rain with pockets of heavy showers
and thunderstorms. Will continue to advertise likely PoPs and a
chance of strong to severe weather in the Hazardous Weather
Outlook.

The low will move through the region Thursday night and across the
Gulf coast states Friday before opening up over northern Florida
Friday night. We may see some lingering showers early Friday but
should begin to dry out late Friday and friday night. We will not
see much if any of a cool down. A fairly large mid level ridge
builds across the central CONUS right behind this system. This will
keep us at or just slightly above normal for temps and generally dry
weather. /CAB/

&&

.AVIATION...Latest surface observations continue to indicate patchy
areas of  dense fog near coastal terminals (HUM and east of GPT
along the MS coastline). This has caused intermittent reduction of
flight categories to IFR/LIFR range. Fog should remain isolated and
primarily located to near coastal terminals early this morning, but
will likely improve through mid morning. No additional hazards are
expected through the forecast period with VFR conditions likely for
all terminals today. KLG

&&

.MARINE...A surface high pressure system continues to dominate the
northern  Gulf coast early this morning leading to relatively weak
winds across all marine zones. This surface high will steadily drift
north and east later today, which in response will begin to shift
winds more from the E to eventual SE through this afternoon and
evening. This onshore flow pattern will persist through mid-week,
before the next storm system is due to arrive by Thursday. ATTM,
long-range models continue to confidently support a cold front to
swing across the northern Gulf, with accompanying showers and
storms. A few of which may be strong to severe with gusty, erratic
winds the main threats. This system will quickly depart the area
Friday followed by a transition to offshore winds following the
frontal passage. KLG

&&

.DECISION SUPPORT...

DSS code: Blue.
Deployed: None.
Activation: None.
Activities: River flood warnings

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.

&&


&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  78  49  80  53 /   0   0   0   0
BTR  77  52  81  56 /   0   0   0   0
ASD  77  53  79  56 /   0   0   0   0
MSY  77  58  79  60 /   0   0   0   0
GPT  73  55  76  58 /   0   0   0   0
PQL  76  52  79  55 /   0   0   0   0

&&

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

$$


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