357
FXUS64 KLIX 291154
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
654 AM CDT Sat Jun 29 2024

...New AVIATION...

.SHORT TERM...
(Today through Sunday)
Issued at 400 AM CDT Sat Jun 29 2024

Main focus over the next 36 hours is likely to be heat related
problems, along with thunderstorm potential.

Upper ridging centered over northeast Texas this morning with a
weakening shear axis extending from central Alabama to near
Houston. At the surface, high pressure centered off the New
England coastline had an extension southwestward into the eastern
Gulf of Mexico. Radar was much quieter early this morning compared
to the previous couple mornings, with only a cluster of showers
over the Pearl River Basin north of Slidell at 3 am CDT. A rather
uncomfortable morning across the area with much of the area
reporting temperatures in the lower and middle 80s at 3 am. The
exceptions were 75 to 80 in southwest Mississippi and the adjacent
Louisiana parishes. For most of the area, dew points ran between
75 and 80.

Near and southeast of the shear axis, precipitable water values
were as high as 2.2 inches, as noted on the 00z LIX sounding, but
closer to 1.75 in areas to the northwest. The shear axis is
gradually forecast to wash out over the next 36 hours. However,
moisture content is forecast to remain in the 2.0-2.25 inch range
across just about the entire area. This is plenty sufficient for
the development of isolated to scattered convection as we reach
the convective temperature both days. That is generally forecast
to be in the 91-94F range. That should mean only isolated
development during the morning hours, with a bit better coverage
during the afternoon hours. While instantaneous areal coverage may
not exceed much more than 30-40 percent, if that, the 12 hour
threat may be closer to 50-60 percent. Most land based convection
should also die out with loss of surface heating, before
redeveloping over marine areas prior to sunrise Sunday.

We shouldn`t have quite the cloud cover today we had Friday
morning, which will allow high temperatures to return to the
middle 90s for a large portion of the area. Dew points in the mid
and upper 70s will produce maximum heat index values in the 108
to 112F range for most of the area this afternoon, with isolated
spots exceeding 112F. Current Heat Advisory remains in place. High
temperatures Sunday look to be a degree or two hotter as upper
ridging presses into the area a little more. So even if the dew
points run a degree or two lower on Sunday, we will likely see
heat index values nudge upward a bit, potentially at or above 113F
in a fair percentage of the area. Excessive Heat Watch remains in
place for Sunday with the expectation that it`ll be upgraded to a
warning in the afternoon forecast package across some or most of
the area.

&&

.LONG TERM...
(Sunday night through Friday)
Issued at 400 AM CDT Sat Jun 29 2024

Upper ridging is likely to remain close enough to the area to
impact much of the workweek. Precipitable water values will
continue to exceed 2 inches for much or all of the area for at
least Monday and Tuesday, with some drying across the north at
midweek. That will mean at least some potential for afternoon
thunderstorms Monday and Tuesday across the entire area, and
primarily from the Interstate 10 corridor southward beyond that
point. Most of the overnight hours should be dry.

Expect little or no relief from oppressive heat for much of the
week, with the exception of any brief cooling from nearby
thunderstorms. Heat Advisory/Excessive Heat Watch/Warning
products are expected to be necessary on Monday in later
forecasts, and potentially for much of the week. If there is going
to be a break in the pattern, at this point it doesn`t appear in
the cards until perhaps next weekend. Heat related illnesses have
a cumulative effect, so impacts are likely to increase as the week
goes on for people that have limited access to cooling.

&&

.AVIATION...
(12Z TAFS)
Issued at 640 AM CDT Sat Jun 29 2024

At forecast issuance timme, all terminals were experiencing VFR
conditions, although KMCB had a brief period of IFR ceilings.
There will be a period of MVFR ceilings this morning as the
cumulus field develops, but in most areas, cloud bases should lift
to or above FL030. Isolated to scattered TSRA are expected to
develop as convective temperatures in the lower 90s are reached by
around 18z, if not a little earlier. With no particular focus for
initiation other than possibly lake/sea breeze boundaries, little
confidence in timing of direct impacts. Will use VCTS for now,
with amendments as necessary if/when direct impacts are
anticipated. Direct impacts would generally entail IFR or lower
visibilities, MVFR ceilings and perhaps wind gusts in excess of 30
knots. Most terminals should see convective threat lower
considerably by 01z or so.

&&

.MARINE...
Issued at 400 AM CDT Sat Jun 29 2024

Primary concerns will be thunderstorm threats for marine
interests, which will usually occur during the late night and
morning hours. There will be the usual increase in wind speeds
during the evening hours across the coastal waters, which could
occasionally top out in the 15-20 knot range, but don`t anticipate
a need for Small Craft Advisories at this time.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  92  74  94  75 /  50  30  60  20
BTR  96  78  98  79 /  60  20  50  20
ASD  94  78  96  78 /  60  20  60  30
MSY  94  79  96  81 /  60  20  50  30
GPT  92  78  95  77 /  50  30  60  40
PQL  95  77  97  77 /  50  30  60  40

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Heat Advisory from 10 AM this morning to 7 PM CDT this evening
     for LAZ034>037-039-046>048-056>060-064-065-071-076>090.

     Excessive Heat Watch from Sunday morning through Sunday evening
     for LAZ034>037-039-046>048-056>060-064-065-071-076>090.

GM...None.
MS...Heat Advisory from 10 AM this morning to 7 PM CDT this evening
     for MSZ068>071-077-083>088.

     Excessive Heat Watch from Sunday morning through Sunday evening
     for MSZ068>071-077-083>088.

GM...None.
&&

$$

SHORT TERM...RW
LONG TERM....RW
AVIATION...RW
MARINE...RW