Heat Advisory 25, NWS New Orleans, LA

Area Forecast Discussion
National Weather Service New Orleans LA
Issued by National Weather Service Mobile AL
1250 PM CDT Sun Sep 5 2021

.AVIATION...VFR generally prevails this afternoon with scattered
to locally broken cloud bases between 3-5 kft AGL. Very localized
MVFR conditions will be possible near isolated to scattered
showers and thunderstorms that will develop through the afternoon.
MVFR ceilings and visibility restrictions could briefly move into
far southern MS near KMCB late tonight or early Monday morning,
but for now confidence was low enough to maintain VFR conditions
in the local TAF past 06.06Z. /21

&&

.PREV DISCUSSION... /Issued by National Weather Service Mobile AL/

MORNING UPDATE...An upper level ridge of high pressure extending
eastward across Louisiana and Mississippi this morning is forecast
to weaken later today into tonight as an upper level trough digs
east of the Mississippi Valley region. An associated weak surface
cold front will push southward into northern and central portions
of Louisiana and Mississippi late this afternoon into this
evening. A moist and unstable airmass will remain in place over
much of the area this afternoon underneath the ridge aloft and
ahead of the approaching boundary. Precipitable water values are
expected to improve to 1.5" to 1.8" across western portions of the
forecast area this afternoon, while a slightly drier/lower PWAT
airmass (1.2-1.5") resides over eastern areas. The increased
moisture along with afternoon MLCAPE values up to 2000-3000 J/KG
will be favorable for the development of scattered showers and
thunderstorms over western/southwestern portions of the forecast
area this afternoon, where we have maintained 30-40% POPs. A
strong storm or two will be possible in this part of the area late
this afternoon. Much lesser coverage (10-20%) should be present
farther east along the LA/MS coast. High temperatures are on track
to range around 90 degrees along the coast and up to around 92-94
degrees farther inland. Maximum heat index readings will range
between 100-105 over most western and central portions of the area
this afternoon, and a Heat Advisory remains in effect. /21

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  92  72  88  70 /  20  30  70  30
BTR  92  73  88  71 /  40  30  70  30
ASD  92  74  91  72 /  20   0  60  30
MSY  93  77  92  76 /  20  10  60  30
GPT  90  74  90  74 /  10   0  50  30
PQL  90  72  90  72 /  10   0  40  20

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Heat Advisory until 6 PM CDT this evening for LAZ034>037-039-
     046>050-056>061-063>067-071-072-075>078.

GM...None.
MS...Heat Advisory until 6 PM CDT this evening for MSZ068>071-077.

GM...None.
&&

Special Weather Statement
National Weather Service New Orleans LA
Issued by National Weather Service Lake Charles LA
228 PM CDT Sun Sep 5 2021

LAZ059-065-066-052000-
Lower Terrebonne LA-Upper Terrebonne LA-Upper Lafourche LA-
228 PM CDT Sun Sep 5 2021

...A strong thunderstorm will impact portions of northeastern
Terrebonne and central Lafourche Parishes through 300 PM CDT...

At 227 PM CDT, Doppler radar was tracking a strong thunderstorm over
Houma, moving south at 10 mph.

HAZARD...Winds in excess of 30 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Houma, Montegut, Bayou Cane, Chauvin, Gray and Dulac.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 2937 9079 2963 9086 2970 9067 2956 9057
      2954 9057 2954 9056 2952 9054 2950 9054
      2950 9052 2948 9051
TIME...MOT...LOC 1927Z 337DEG 11KT 2959 9073

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...30 MPH

Brazzell