Severe Thunderstorm Warning 83, NWS New Orleans, LA

Area Forecast Discussion
National Weather Service New Orleans LA
427 PM CDT Sat Jun 30 2018

.DISCUSSION...
A few showers and thunderstorms have developed across the
forecast area. These showers and storms should diminish over the
next few hours. For Sunday expect more of the same...warm
temperatures and more coverage of showers and storms as a low
pressure drifts towards the region. By Monday the low pressure
will be closer and precipitable water values creep into the 2 inch
range. Have carried likely pops for Monday. The heavy rain threat
increases on Tuesday as precipitable water values increase to the
2.2 to 2.4 inch range. Looking at some of the data, the
precipitable water values are close to the record daily max for
Tuesday. Combine that with a slow moving low pressure system, slow
moving storms, and deep warm cloud layers...heavy rainfall will
be a issue for the forecast area early this week but especially on
Tuesday. The Weather Prediction Center has portions of the area
in a Marginal Risk of Excessive Rainfall for Sunday and Monday.
Look for these to be possibly expanded or upgraded as we go on in
time. Elevated rain chances continue for most of the week as more
waves of energy move across the region. This will allow for
periods of showers and storms throughout the week.

&&

.AVIATION...
A few SHRA have developed across the southeast Louisiana and
coastal Mississippi. Additional development with TSRA will occur
mainly east of I-55. Stronger storms over southern Alabama are
expected to dive southeast across Mississippi coast between 20 and
00z. Have inserted tempo group with TS and gusts up to 40 knots
to cover this threat. Lower conditions associated with heavier
rain cells should be brief and dissipate by 01z. Therefore, will
mainly carry VCSH and VCTS for other sites with the prevailing VFR
conditions through Sunday morning.

&&

.MARINE...
High pressure covering much of the Gulf of Mexico will persist this
weekend. Expect mostly westerly winds around 10 knots or less
through Sunday night. A weak and broad area of surface low
pressure should move over the coastal waters by early next week.
The surface pressure gradient associated with the low is expected
to remain relatively weak...so no major coastal impacts are
expected. Areas of thunderstorms will be increasing over
the next several days through early next week, so expect periodic
higher winds and waves in and around convection.

&&

.DECISION SUPPORT...
DSS code: Blue.
Deployed: None.
Activation: None.
Activities: Heat Advisory.

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  75  92  73  89 /  20  40  20  60
BTR  76  94  75  91 /  10  40  20  60
ASD  77  91  76  87 /  30  70  40  70
MSY  78  91  77  88 /  30  60  40  70
GPT  78  89  76  86 /  30  60  40  80
PQL  75  89  74  86 /  30  60  50  90

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Heat Advisory until 7 PM CDT this evening for LAZ039-040-049-050-
     056>072.

GM...None.
MS...Heat Advisory until 7 PM CDT this evening for MSZ077-080>082.

GM...None.
&&

Hazardous Weather Outlook
National Weather Service New Orleans LA
1254 PM CDT Sat Jun 30 2018

GMZ530-532-534-536-538-550-552-555-557-570-572-575-577-LAZ034>037-
039-040-046>050-056>072-MSZ068>071-077-080>082-010600-
Lake Pontchartrain and Lake Maurepas-Mississippi Sound-
Lake Borgne-Chandeleur Sound-Breton Sound-
Coastal Waters from Port Fourchon LA to Lower Atchafalaya River
LA out 20 nm-
Coastal waters from the Southwest Pass of the Mississippi River
to Port Fourchon Louisiana out 20 NM-
Coastal Waters from Boothville LA to Southwest Pass of the
Mississippi River out 20 nm-
Coastal waters from Pascagoula Mississippi to Stake Island out
20 NM-
Coastal waters from Port Fourchon Louisiana to Lower Atchafalaya
River LA from 20 to 60 NM-
Coastal waters from Southwest Pass of the Mississippi River to
Port Fourchon Louisiana from 20 to 60 NM-
Coastal Waters from Stake Island LA to Southwest Pass of the
Mississippi River from 20 to 60 nm-
Coastal waters from Pascagoula Mississippi to Stake Island
Louisiana out 20 to 60 NM-Pointe Coupee-West Feliciana-
East Feliciana-St. Helena-Washington-St. Tammany-Iberville-
West Baton Rouge-East Baton Rouge-Ascension-Livingston-Assumption-
St. James-St. John The Baptist-Upper Lafourche-St. Charles-
Upper Jefferson-Orleans-Upper Plaquemines-Upper St. Bernard-
Upper Terrebonne-Lower Terrebonne-Lower Lafourche-Lower Jefferson-
Lower Plaquemines-Lower St. Bernard-Northern Tangipahoa-
Southern Tangipahoa-Wilkinson-Amite-Pike-Walthall-Pearl River-
Hancock-Harrison-Jackson-
1254 PM CDT Sat Jun 30 2018

This Hazardous Weather Outlook is for portions of Southeast
Louisiana...South Mississippi and the adjacent coastal waters.

.DAY ONE...This Afternoon and Tonight

Afternoon heat indices are expected to rise to 105 to 108 degrees
through the early afternoon hours. Take extra precautions if you
work or spend time outside to avoid heat illnesses.

In addition, a few strong thunderstorms will be possible this
afternoon. The main threats will be gusty winds, frequent
lightning and locally heavy rainfall.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

Thunderstorm coverage will become more numerous Monday through
Wednesday. Severe weather is not expected but a few storms could
become strong, producing gusty winds and frequent lightning.

However, heavy rainfall will be possible and could lead to street
flooding, ponding of water in low lying areas and areas of poor
drainage Monday through Wednesday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

Special Weather Statement
National Weather Service New Orleans LA
257 PM CDT SAT JUN 30 2018

MSZ082-302030-
Jackson-
257 PM CDT SAT JUN 30 2018

...A STRONG THUNDERSTORM WILL AFFECT SOUTHEASTERN JACKSON COUNTY...

At 256 PM CDT, a cluster of strong thunderstorms was located over
Moss Point, moving west at 5 mph.

Winds in excess of 30 mph are possible with this storm.

Locations impacted include...
Moss Point, Escatawpa, Gautier, Hickory Hills, Helena and Vancleave.

LAT...LON 3036 8845 3033 8845 3032 8850 3034 8851
      3033 8852 3034 8857 3037 8859 3036 8860
      3037 8862 3036 8861 3037 8863 3036 8865
      3051 8869 3052 8843 3035 8839
TIME...MOT...LOC 1956Z 076DEG 6KT 3042 8849

Special Weather Statement
National Weather Service New Orleans LA
414 PM CDT SAT JUN 30 2018

LAZ056-065-066-302145-
Lower Terrebonne-Upper Terrebonne-Assumption-
414 PM CDT SAT JUN 30 2018

...A STRONG THUNDERSTORM WILL AFFECT TERREBONNE AND SOUTH CENTRAL
ASSUMPTION PARISHES...

At 413 PM CDT, a strong thunderstorm was located 15 miles west of
Dulac, or 19 miles southwest of Houma, moving northwest at 10 mph.

Winds in excess of 30 mph are possible with this storm.

Locations impacted include...
Dulac, Cocodrie, Tambour Bay Buoy and Lumcon Center Buoy.

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 2918 9096 2922 9121 2931 9134 2937 9124
      2925 9113 2926 9112 2954 9127 2963 9108
      2974 9111 2981 9106 2929 9054 2926 9059
      2921 9054 2925 9061 2922 9064 2914 9065
      2909 9086
TIME...MOT...LOC 2113Z 140DEG 9KT 2940 9096