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

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FXUS64 KLIX 260423
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
1123 PM CDT Sat Mar 25 2017

.AVIATION...
VFR conditions initially should see marine layer cloud deck advect
overnight for a period of MVFR ceilings and radiational fog from
residual moisture of earlier rainfall. COnditinos should improve
to VFR by mid-morning and prevailing through the early evening
hours before marine layer advection MVFR cloud deck returns
towards latter portion of valid TAF period and beyond. 24/RR

&&

DECISION SUPPORT...
DSS CODE...Green
DEPLOYED...None.
ACTIVATION...None.
ACTIVITIES...None.

Decision Support Service (DSS) Code Legend:
GREEN  = No weather impacts that require action
BLUE   = Long fused Watch/Warning/Advisory in effect or high
         visibility event
YELLOW = Heightened impacts with short fused
         Watch/Warning/Advisory issuances; Radar support
ORANGE = High Impacts - Slight to Moderate risk of severe weather;
         Nearby tropical events, HAZMAT or other large episodes
RED    = Full engagement for moderate risk of severe weather; Direct
         tropical threats; events of national significance.

&&

.PREV DISCUSSION... /issued 722 PM CDT Sat Mar 25 2017/

UPDATE...
Updated coastal waters forecast to remove Small Craft Advisory
headline. Also updated Enhanced Hazardous Weather Outook graphics
and Hazardous Weather Outlook text product for the all clear for
the remainder of the evening. No other changes at this time. 24/RR

PREV DISCUSSION... /issued 430 PM CDT Sat Mar 25 2017/

SHORT TERM...Convection impacted the region much of the day. First
line of storms never quiet made it to the Pearl River and the
southern edge of the line ended up sagging way back to the southwest
into south-central and even southwestern LA. Convection fired along
the cold front back in southeast TX and moved into southwest LA but
additional convection that wasn`t anticipated fired between the two
main lines (basically the southern edge of the first line that was
left behind). This activity filled in and moved into the region late
this morning bringing about numerous reports of small hail and a few
severe hail reports upt to 2 inches around Pearl River and the
Pearl River Wildlife Management Area.

Tonight and tomorrow...should be quiet for the most parts as the
system responsible for today`s storms lifts north and the trough
axis pushing east of the region. That said the cold front
associated with this system will stall just off to our northwest
this evening and then quickly lifting north through the Lower MS
Valley as a warm front tomorrow morning. This will lead to
dewpoints remaining in the 60s and increasing tomorrow with a warm
day on tap. H925 temps of 19-20C suggest highs in the lower 80s
with a few locations likely touching 85-86. Tomorrow should be dry
but maybe a rogue shower or two could develop. Rain chances will
be a tad higher Mon and Tue.

As for the beginning of the work week the next system will quickly
be pushing into the Lower MS Valley. This system will be a little
weaker but will be moving more east instead of lifting north. This
will try to drive a cold front towards the region and provide
forcing for showers and thunderstorms mainly across the northern
half of the CWA. Once again the cold front will likely stall out
but it could actually just sneak into the CWA and provide focus
for afternoon showers and thunderstorms across the north Tuesday.

As for severity Monday afternoon could have a few potent storms. A
mid level jet core of 45-50 kts will swing through the northern
portions of the CWA. This combined with 1000-15 j/kg sfc based CAPE
and mid level lapse rates around 6.5-7 C/km. Not anticipating many
but a few storms could be capable of producing severe hail and wind
gusts. Again this is mainly across the north as the forcing quickly
weakens the closer we get to the coast.

LONG TERM...Main focus in the long term is the system around the
end of the work week. There are some timing and strength difference.
Another potent storm system is expected to drop south along the Pac
coast before deepening and eventually closing off over the 4
corners. It never quite becomes cut off so it continue to slide east
into the Plains but the GFS is deeper, slightly slower, further
south and a stronger frontal passage. The ECMWF on the other hand is
still deep with the system but has more of a connection with the
northern stream so it is a tad faster, further north, and a messier
frontal passage Thursday/Thursday night. Will stick with a blend of
the models but will show high PoPs for both Thursday and Thursday
night. If the GFS soln comes to fruition then the risk for severe
weather will be higher Thursday and SPC is outlooking the area just
off to our northwest for Wednesday and into Thursday. /CAB/

AVIATION...

The convective threat is waning with all of the terminals free of
thunderstorm threat in the next two hours.  A period of VFR
conditions should take hold at all of the terminals after 00z and
then continue through around 08z.  After 08z, the combination of
light boundary layer flow and ample low level moisture should result
in a period of low ceilings and fog at all of the terminals.
Ceilings should drop to between 300 and 500 feet and visibilities
could fall to 1 mile or less at a few of the terminals.
KMCB...KBTR...and KHDC have the highest probability of seeing LIFR
and VLIFR visibility restrictions.  32

 &&

MARINE...

The pressure gradient over the coastal waters will weaken a bit
tonight allowing for the onshore flow to decrease to 10 to 15 knots
through tomorrow.  Seas should also drop to 2 to 4 feet in the open
Gulf waters by tomorrow afternoon.  However, another low pressure
system will pass north of the area on Monday.  This system should
increase the pressure gradient enough over the Gulf to push winds
back into exercise caution range of 15 to 20 knots.  As the low
moves away Monday night, winds should relax back to 10 to 15 knots
and remain in that range through Tuesday evening.  This brief
respite in stronger onshore flow will give way to another round of
small craft advisory conditions for Wednesday and Thursday as a much
stronger low pressure system passes north of the area.  Seas will
respond to this increase in winds and rise back to around 7 to 8
feet in the offshore waters. 32

DECISION SUPPORT...
DSS CODE...Yellow.
DEPLOYED...None.
ACTIVATION...None.
ACTIVITIES...Monitoring Severe Weather Potential.

Decision Support Service (DSS) Code Legend:
GREEN  = No weather impacts that require action
BLUE   = Long fused Watch/Warning/Advisory in effect or high
         visibility event
YELLOW = Heightened impacts with short fused
         Watch/Warning/Advisory issuances; Radar support
ORANGE = High Impacts - Slight to Moderate risk of severe weather;
         Nearby tropical events, HAZMAT or other large episodes
RED    = Full engagement for moderate risk of severe weather; Direct
         tropical threats; events of national significance.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  62  84  64  82 /  30  10  10  30
BTR  65  86  65  83 /  20  10  10  30
ASD  64  82  65  83 /  20  10  10  20
MSY  68  85  67  82 /  20  10  10  20
GPT  66  82  66  78 /  40  10  10  20
PQL  65  82  65  81 /  50  10  10  20

&&

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

$$



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