Southwest Pass of the Mississippi River to Port Fourchon Louisiana Marine Forecast
|Today...East Winds 15 To 20 Knots. Seas 3 To 6 Feet. Dominant Period 8 Seconds. Chance Of Showers In The Late Morning And Afternoon. Slight Chance Of Thunderstorms In The Afternoon.|
|Tonight...East Winds 15 To 20 Knots. Seas 3 To 5 Feet With Occasional Seas To 6 Feet. Dominant Period 7 Seconds. Chance Of Showers And Slight Chance Of Thunderstorms Through The Night.|
|Friday...East Winds 10 To 15 Knots. Seas 3 To 5 Feet. Dominant Period 7 Seconds. Chance Of Showers In The Morning. Slight Chance Of Thunderstorms Through The Day. Showers Likely In The Afternoon.|
|Friday Night...Northeast Winds 10 To 15 Knots. Seas 2 To 4 Feet. Dominant Period 7 Seconds. Chance Of Showers Until Early Morning.|
|Saturday...Northeast Winds 10 To 15 Knots. Seas 2 To 4 Feet. Dominant Period 7 Seconds. Slight Chance Of Showers And Thunderstorms In The Afternoon.|
|Saturday Night...East Winds 10 To 15 Knots. Seas 2 To 4 Feet. Dominant Period 6 Seconds.|
|Sunday...East Winds 5 To 10 Knots. Seas 1 To 2 Feet. Dominant Period 6 Seconds.|
|Sunday Night...Southeast Winds 10 To 15 Knots. Seas 1 To 2 Feet. Dominant Period 4 Seconds.|
|Monday...East Winds 10 To 15 Knots. Seas 1 To 2 Feet. Dominant Period 4 Seconds.|
|Monday Night...East Winds 10 To 15 Knots. Seas 2 To 4 Feet. Dominant Period 5 Seconds.|
| Synopsis for Pascagoula to SW Pass Mississippi - GMZ501|
Synopsis for SW Pass Mississippi River to Atchafalaya River- GMZ500
351 AM CDT Thu Oct 22 2020
A low pressure system over the eastern Gulf and a broad area of high pressure over the Southeast will keep easterly flow in place through early next week.
| Area Forecast Discussion|
National Weather Service New Orleans LA
416am CDT Thu Oct 22 2020
Short Term - Today Through Friday
The recent dry spell will be coming to an end today. The Bermuda ridge will push westward towards the area today. This, combined with surface high pressure centered over the Appalachian Mountains moving southward will enhance southeasterly flow across the CWA. That flow regime will start bringing the pool of high PW air located over the Gulf of Mexico into the local area. At the same time, a broad trough will be dropping out of Canada into the central plains. So, we'll have moisture and decreasing subsidence. That will be the recipe for convective development. Therefore, am expecting scattered showers and possible a few thunderstorms today and Friday. Temps will still be above normal but gradually coming down as 500mb heigheights fall with the trough moving in. The cold front associated with the trough just won't have enough push behind it to do much more than stall by the time it gets down to the Gulf Coast.
.LONG TERM (Saturday through Wednesday)... A largely zonal flow pattern is expected to dominate the Gulf South over the weekend. A much drier airmass will advect into the area and precipitable water values should decrease to around 1.25 inches by Sunday. This dry airmass will contribute to very weak lapse rates and limited cloud development on both Saturday and Sunday. Temperatures should also warm to well above average in the middle to upper 80s by Sunday due to a combination of stronger solar insolation and drier air.
A broad ridge axis will set up across the eastern Gulf and western Atlantic by early next week. Deep layer southwest flow will be the rule across the forecast area, and this will allow for a more humid and unstable airmass to take hold of the area by next Tuesday and Wednesday. Monday should be day of transition as deeper Gulf moisture begins to feed into the region, and precipitable water values should increase from around 1.1 inches in the morning to 1.5 inches by the evening hours. Conditions will remain largely unfavorable for convection to form, but cloud development will increase greatly as compared to the weekend. By Tuesday, enough instability will be in place to support the development of isolated to scattered convection in the afternoon hours. The persistent southwest flow regime will allow temperatures to remain above average with highs in the lower to middle 80s and lows in the upper 60s and lower 70s through the middle of next week.
Until the 00z run, model differences were quite significant next week with the GFS showing a more progressive upper level low moving across the southern US by Friday and the ECMWF (European Centre for Medium-Range Weather Forecasts) with a much slower solution. The ECMWF has come much more in line with the GFS. If this solution of warm temperatures and increasing moisture with an upper low moving across the region does actually take place, there will certainly be a possibility for severe weather.
NOAA New Orleans LA Office: Watches - Warnings - Advisories
LA...None. GM...None. MS...None. GM...None.