Marine Weather Net

Stake Island, LA to Southwest Pass of the Mississippi River out 20 - 60 NM Marine Forecast


REST OF TONIGHT

N
WINDS
20 - 25
KNOTS

TUESDAY

N
WINDS
20 - 25
KNOTS

TUESDAY NIGHT

NE
WINDS
15 - 20
KNOTS

WEDNESDAY

E
WINDS
10 - 15
KNOTS

The Marine Weather Forecast In Detail:
GMZ575 Forecast Issued: 817 PM CST Mon Jan 20 2020

SMALL CRAFT ADVISORY IN EFFECT THROUGH TUESDAY MORNING
Rest Of Tonight...North Winds 20 To 25 Knots. Seas 5 To 8 Feet With Occasional Seas To 10 Feet. Dominant Period 6 Seconds. Waves Or Seas Subsiding To 3 To 6 Feet With Occasional Seas To 8 Feet. Dominant Period 6 Seconds After Midnight.
Tuesday...North Winds 20 To 25 Knots. Seas 4 To 7 Feet With Occasional Seas To 9 Feet. Dominant Period 6 Seconds.
Tuesday Night...Northeast Winds 15 To 20 Knots. Seas 3 To 6 Feet With Occasional Seas To 8 Feet. Dominant Period 5 Seconds. Waves Or Seas Subsiding To 3 To 5 Feet With Occasional Seas To 5 Feet. Dominant Period 5 Seconds After Midnight.
Wednesday...East Winds 10 To 15 Knots. Seas 3 To 5 Feet. Dominant Period 6 Seconds.
Wednesday Night...Southeast Winds Near 15 Knots. Seas 3 To 5 Feet. Dominant Period 6 Seconds. Chance Of Showers After Midnight.
Thursday...Southeast Winds 15 To 20 Knots. Seas 3 To 5 Feet With Occasional Seas To 6 Feet. Dominant Period 5 Seconds. Chance Of Showers In The Morning, Then Showers Likely In The Afternoon.
Thursday Night...Southwest Winds 15 To 20 Knots Becoming West After Midnight. Seas 3 To 6 Feet. Dominant Period 7 Seconds. Showers Likely.
Friday...Northwest Winds 15 To 20 Knots. Seas 3 To 6 Feet With Occasional Seas To 8 Feet. Dominant Period 7 Seconds. Chance Of Showers And Thunderstorms Through The Day.
Friday Night...North Winds 15 To 20 Knots. Seas 3 To 6 Feet With Occasional Seas To 8 Feet. Dominant Period 5 Seconds.
Saturday...North Winds 15 To 20 Knots. Seas 3 To 6 Feet With Occasional Seas To 8 Feet. Dominant Period 5 Seconds. Waves Or Seas Subsiding To 3 To 5 Feet With Occasional Seas To 5 Feet. Dominant Period 5 Seconds In The Afternoon.
Saturday Night...North Winds 10 To 15 Knots. Seas 2 To 4 Feet. Dominant Period 4 Seconds.
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Synopsis for Pascagoula to SW Pass Mississippi - GMZ501
Synopsis for SW Pass Mississippi River to Atchafalaya River- GMZ500
817 PM CST Mon Jan 20 2020

Cold high pressure over the Deep South will remain settled through Wednesday before moving east Thursday. The next storm system will deliver rain and thunderstorms Thursday, before quickly exiting the area on Friday.
Area Forecast Discussion
National Weather Service New Orleans LA
1112pm CST Monday Jan 20 2020

AVIATION... VFR conditions will prevail at all terminals through the forecast period. Winds will remain elevated KMSY and KNEW due to nocturnal marine marine influence. All terminals will see a rotation in wind direction from north to northeast late Tuesday afternoon. The winds will continue rotating towards southeast with time beyond the forecast period.

SHORT TERM...A strong vort lobe and associated re-enforcing cold front will sweep through the area tonight. This front will be moisture starved, so little to no evidence of the front moving through is to be expected. The main impact will be continued cold air advection into the region which will keep temperatures substantially below average through Wednesday. A decent freeze is expected to occur across most of the area tonight and again tomorrow night, and have a freeze warning out for most of the forecast area tonight. Only areas immediately south of Lake Pontchartrain and along the Louisiana coast should remain above freezing tonight. The freeze warning includes areas west and north of Lake Pontchartrain, and below freezing conditions could last 8 to 12 hours across portions of the area in Southwest Mississippi tonight. The reason for issuing another freeze warning north of the I-10 corridor is the recent warm spell and indications of a bloom occurring. This "false Spring" has made plants in the region more susceptible to damage from the freezing conditions the next couple of nights.

Mid and high level cloud cover will begin to increase tomorrow night and should be thick enough to produce overcast conditions by Wednesday. This increase in cloud cover is related to a southern stream impulse pushing out of the Four Corners and into the Southern Plains. However, the low levels will remain very dry on Wednesday. At most, a few light rain showers may develop in areas near the Atchafalaya basin by the end of the day. Temperatures will remain cooler than average with highs in the low to mid 50s expected.

As winds turn more southeasterly Wednesday night, low level moisture will begin to advect into the area. The prospect for rain will increase through the night, and expect to see scattered to numerous light rain showers across most of the forecast area by daybreak on Thursday. The onshore flow will also bring some warmer air back into the area, and forecast overnight lows several degrees warmer in the 40s and lower 50s.

LONG TERM...Thursday will be a rather unsettled day as the Pacific based trough axis and an associated weak surface low slides through the Gulf South. Strong difluence in the upper levels will produce high omega values and forcing throughout the atmospheric column. In the low levels, a triple point will sweep through the area as the low passes directly across Southeast Louisiana and coastal Mississippi. Fortunately, low level dynamics and instability will remain rather limited. Thus, although some thunderstorm activity could fire up in advance of the low Thursday afternoon and evening, the risk of severe thunderstorm activity is basically non-existent. Temperatures should warm into the upper 50s and lower 60s on Thursday. The surface low should sweep to the east of the area by Friday morning, and expect to see rapidly improving conditions take hold through the day on Friday. Morning showers and thunderstorms mainly over the coastal waters will give way to clearing skies by the afternoon hours. This rapid clearing will be driven by strong negative vorticity advection and dry air advection occurring across the Gulf South in the wake of the departing trough axis. Little in the way of cold air advection is expected behind the trough, and temperatures should be near normal on Friday.

A surface high will settle over the area for the weekend, and this will keep dry weather and near normal temperatures in place across most of the CWA on Saturday and Sunday. Some high cloud cover may spread into the area as a jet streak moves across the western and central Gulf of Mexico. This jet streak should only bring some mid to high level cloud cover to the most of the CWA this weekend. At most, a few showers could develop over the the coastal waters south of Louisiana Sunday into Sunday night. Highs will be in the low to middle 60s each day, and lows will cool into the 40s.

MARINE...Expect persistent gusty northerly winds in the short- term across all marine zones. For nearshore coastal tidal lakes and sounds, winds have steadily diminished which allowed for dropping Small Craft Advisories, however have extended Small Craft highligheights for the Brenton/Chandeleur sounds as well as all outer Gulf zones through early tomorrow morning, as winds will remain sustained right around advisory criteria - with frequent gusts above advisory criteria expected. Otherwise, winds will steadily diminish late Tuesday and into Wednesday, as winds shift more from the E to eventual SE. Next storm system will deliver widespread rain on Thursday, which may bring hazardous marine conditions including gusty, erratic winds and some thunderstorms before drying out Friday and into the upcoming weekend. KLG

DECISION SUPPORT... DSS code: Blue. Deployed: None. Activation: None. Activities: Forecast support for Stennis. Small craft advisory. 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.

NOAA New Orleans LA Office: Watches - Warnings - Advisories
LA...Freeze Warning until 9am CST Tuesday for LAZ034>037-039-040- 046>050-056>059-065-071-072.

GM...Small Craft Advisory until 9am CST Tuesday for GMZ536-538-555- 557-570-572-575-577.

MS...Freeze Warning until 9am CST Tuesday for MSZ068>071-077-080>082.

GM...Small Craft Advisory until 9am CST Tuesday for GMZ538-555-557- 570-572-575-577.