Marine Weather Net

Chandeleur Sound Marine Forecast


REST OF TONIGHT

SW
WINDS
5 - 10
KNOTS

TUESDAY

N
WINDS
25
KNOTS

TUESDAY NIGHT

NE
WINDS
25
KNOTS

WEDNESDAY

NE
WINDS
15 - 20
KNOTS

The Marine Weather Forecast In Detail:
GMZ536 Forecast Issued: 952 PM CST Mon Nov 11 2019

GALE WARNING IN EFFECT FROM 3 AM CST TUESDAY THROUGH TUESDAY AFTERNOON ...SMALL CRAFT ADVISORY IN EFFECT FROM TUESDAY EVENING THROUGH LATE TUESDAY NIGHT...
Rest Of Tonight...Southwest Winds 5 To 10 Knots Becoming West 15 To 20 Knots After Midnight, Then Becoming North 25 To 30 Knots With Gusts To 40 Knots After 3 Am. Waves 1 Foot Or Less Building To 4 To 7 Feet With Occasional Waves To 8 Feet. Dominant Period 4 Seconds. Chance Of Showers In The Late Evening And Early Morning, Then Showers Likely After 3 Am.
Tuesday...North Winds 25 To 35 Knots. Waves 4 To 7 Feet With Occasional Waves To 9 Feet. Dominant Period 4 Seconds. Chance Of Light Rain Until Late Afternoon.
Tuesday Night...Northeast Winds 25 To 30 Knots. Waves 3 To 6 Feet With Occasional Waves To 8 Feet. Dominant Period 4 Seconds.
Wednesday...Northeast Winds 15 To 20 Knots Easing To Near 10 Knots Late In The Afternoon. Waves 3 To 5 Feet. Dominant Period 4 Seconds.
Wednesday Night...Northeast Winds 10 To 15 Knots. Waves 2 To 4 Feet. Dominant Period 4 Seconds. Chance Of Sprinkles After Midnight.
Thursday...Northeast Winds 10 To 15 Knots. Waves 2 To 4 Feet. Dominant Period 4 Seconds. Chance Of Showers.
Thursday Night...North Winds 15 To 20 Knots. Waves 3 To 5 Feet With Occasional Waves To 6 Feet. Dominant Period 4 Seconds. Chance Of Showers In The Evening, Then Chance Of Sprinkles After Midnight.
Friday...North Winds 15 To 20 Knots. Waves 3 To 5 Feet With Occasional Waves To 6 Feet. Dominant Period 4 Seconds.
Friday Night...North Winds 15 To 20 Knots. Waves 3 To 5 Feet. Dominant Period 4 Seconds.
Saturday...North Winds 15 To 20 Knots Becoming Northeast Near 10 Knots Late In The Afternoon. Waves 3 To 5 Feet. Dominant Period 4 Seconds. Waves Subsiding To 1 To 2 Feet. Dominant Period 4 Seconds In The Afternoon.
Saturday Night...Northeast Winds 10 To 15 Knots. Waves 1 To 2 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
952 PM CST Mon Nov 11 2019

A very strong cold front will move through the tidal lakes, sounds and coastal waters late tonight and early Tuesday morning, ushering in widespread gales. High pressure will then build into the central Gulf coast region Wednesday. A surface low should develop along the old frontal boundary offshore and move northeast Thursday through Friday. High pressure then settles into the area once again over the weekend.
Area Forecast Discussion
National Weather Service New Orleans LA
834pm CST Monday Nov 11 2019

Updated winds to account for latest trends in current observations behind the cold front and the latest wind guidance with a preference towards the stronger solutions. Given the fairly high confidence in seeing sustained winds 25 mph or higher and gusts of 35 to 40 mph, have issued a Wind Advisory for the entire forecast area starting in the far northwest at midnight tonight and remainder of area after 3 am. Periods with these higher winds are likely to continue through the morning in the northwest inland areas, but likely continuing into at least mid afternoon for areas closer to the tidal lakes and coast with some stronger winds likely occurring into Tuesday evening across the south shoreline areas of Lake Pontchartrain. The anticipated advisory conditions may be a little more marginal in the more inland areas/northwest 1/3 or the forecast area, but given the upstream observations it is likely the prevailing lower wind forecast will be exceeded at times. As is often the case in these situations, stronger winds up at 1 to 2 thousand feet will likely mix down most efficiently near and over larger water bodies, so the stronger 25 to 30 mph sustained winds with gusts around 40 mph will likely occur near the south shore of Lake Pontchartrain into the downtown New Orleans area where the typical funneling occurs between the taller buildings. In fact, would not be surprised to see a period of two of sustained winds possibly near or exceeding 35 mph with some gusts to 45 mph near the lakefront of St. Charles, Jefferson and Orleans Parishes.

Also modified the weather/precipitation type slightly for the final few hours late tonight/early tomorrow before all precipitation ends based on latest guidance trends and model soundings. There is a slight chance of a light mix of a combination of rain, freezing rain and a few sleet pellets over portions of southwest Mississippi during the 6 to 8 am time frame. Regarding impacts, there should be none since the ground will still be relatively warm, and the chance of measurable freezing or frozen precipitation is low. Therefore, even icing on elevated surfaces is a low probability at this point, but this should be monitored as daybreak approaches.

Marine
Will likely upgrade the tidal lakes from a Small Craft Advisory to a Gale Warning with the soon to be issued Coastal Waters Forecast, and add a Small Craft Advisory after the Gale Warning to account for the period where winds remain above 20 knots.

22/TD

SHORT TERM... Long anticipated Arctic cold front is just about to cross into NW Louisiana from the Arklatex this hour. The initial wind shift should enter SW Mississippi around 9 pm, KMCB 10 pm, KBTR 11 pm, KHDC midnight, KNEW/KGPT between 1-2 am, KPQL 2 am. Deeper, colder air and winds may be in lag about 1 to 2 hours after initial wind shift but by daybreak, all areas should be in full bore cold air advection with temperatures falling early, leveling off and warming slowly as clouds thin later in the day. Anticipating clouds to clear for optimal radiational cooling coupled with deep drainage trajectory and weaker cold air advection to bring temperatures to record lows for mid-November. After some collaboration with surrounding offices, attempting to get W/W/A align with neighbors and best convey the message. We are probably a bit early for Freeze Warning but given the higher than normal confidence for this event, have blended with the surrounding offices on Freeze Warning for tomorrow night. The four SW MS counties could be a Hard Freeze Warning, but this would look awkward, so addressing in the Freeze Warning and leaving room to upgrade on next couple of packages if still indicated for tomorrow night.

LONG TERM... Fortunately, this arctic event appears to be very short-lived with a warming trend expected to onset later Wednesday as the frontal zone becomes quasi-stationary across the lower gulf and some rippling takes place to induce some weak isentropic lift over the boundary. This is a softer solution than previously indicated with PoPs lower than before for Thursday. Re-enforcing high pressure builds latter part of the week to maintain colder than normal conditions but not as cold as Tuesday night/Wednesday morning.

Marine Discussion
Front should start to slip off the coast around 2-3 am off LA coast and 3-4 am MS coast. North winds should increase rather abrupartly with cold air advection hitting the warmer waters to ramp winds to near gale conditions towards daybreak. Gale Warning placed for 3 am west of the river, and 6 am east of the river through about sunset Tuesday. Seas to build to 14-17 feet well offshore. Conditions improve steadily after cold air advection abates Tuesday night with considerably lighter winds and lowering seas expected for Wednesday. Another surge of cool air moves off the coast Friday but with lesser affect than the initial front.

DECISION SUPPORT... DSS code: Blue. Deployed: None. Activation: None. Activities: River flooding. Forecast support to City of New Orleans for building collapse. Gale Warning tonight; Freeze Warning Tuesday Night.

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...Wind Advisory from 3am to 3pm CST Tuesday for LAZ039-040-049- 050-056>070-072.

Freeze Warning from midnight Tuesday night to 7am CST Wednesday for LAZ056>059-065.

Freeze Warning from 8pm Tuesday to 8am CST Wednesday for LAZ034>037-039-040-046>050-071-072.

Wind Advisory from midnight tonight to noon CST Tuesday for LAZ034>037-046>048-071.

GM...Gale Warning from 3am to 5pm CST Tuesday for GMZ550-552-570- 572.

Gale Warning from 6am to 5pm CST Tuesday for GMZ532-536-538- 555-557-575-577.

Small Craft Advisory from 3am to noon CST Tuesday for GMZ530- 534.

MS...Wind Advisory from 3am to 3pm CST Tuesday for MSZ077-080>082.

Freeze Warning from 8pm Tuesday to 8am CST Wednesday for MSZ077-080>082.

Wind Advisory from midnight tonight to noon CST Tuesday for MSZ068>071.

Freeze Warning from 6pm Tuesday to 8am CST Wednesday for MSZ068>071.

GM...Gale Warning from 3am to 5pm CST Tuesday for GMZ552-570-572.

Gale Warning from 6am to 5pm CST Tuesday for GMZ536-538-555- 557-575-577.

Small Craft Advisory from 3am to noon CST Tuesday for GMZ534.