410 FXUS64 KLIX 070901 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 301 AM CST Sun Nov 7 2021 .SYNOPSIS... Upper trough extending from the Carolina coast into the extreme eastern Gulf of Mexico, with ridging across the middle third of the country. At the surface, high pressure extended from Pennsylvania into northern Louisiana. No significant cloud cover over the CWA at 3 AM CST, but there are a few patches of fog, mainly in the River Parishes from New Roads to Gonzales. Temperatures were mainly in the 40s, but ranged from 38 at Pascagoula to the mid 50s in the New Orleans metro area. && .SHORT TERM (through Tuesday)... Will be monitoring fog over the next few hours and can't rule out issuance of a Fog Advisory. At the surface, high pressure will remain anchored over the Appalachians through Tuesday as weak upper ridging builds across the area. A shortwave will try to move overtop the ridging on Tuesday, but will have no moisture to work with. Precipitable water values will generally remain around 0.40 inches or less. No precipitation expected through the short term portion of the forecast. Temperatures at 925 mb would argue for high temperatures today being about 3 degrees F warmer than Saturday, another 3-4 degrees warmer on Monday, and another 2-3 degrees Tuesday. Any adjustment to overnight lows would be to shade them down a bit. Diurnal temperature ranges of 25-30 degrees will be rather common the next few days, especially away from coastlines. && .LONG TERM (Tuesday night and beyond)... All indications from the guidance is we will see a fairly good cool down late in the extended portion of the forecast. Biggest question mark is timing. The ECS and GFES are both in phenomenal agreement with the pattern while the ECMWF op is in better agreement with them than the GFS op run. That said the GFS has handled things better lately. All you have to do is look back at this weekend and Thursday. GFS was the drier and warmer model and was absolutely right on with the PoPs but the NBM handled the temps a little better. A rather similar solution looks like it is setting up at the end of the work week. With that we will lean towards the GFS with respect to PoPs on Thursday but will hedge towards the NBM 4.1 with respect to temps. Heading into the middle of the work week the ridge that has dominated the sern CONUS will be suppressed to the south as a L/W trough starts to develop and dig over the Plains. By late Wednesday and into Thursday southerly flow in the low levels will finally develop and that should allow for moisture to slowly return. We are and should remain quite dry through the first half of the week so it will take some time to moisten the airmass up with PWs likely finally abv 1" by midday Thursday for northwest portions of the CWA. We will begin to see southwest flow increase as the trough continues to deepen to the west Thursday. However, with the trough deepening to the west one would expect the system to slow down a little and it actually keeps the mid lvl hghts from falling over the region through the day. There is also no real isentropic lift/WAA regime setting up to see shower activity develop. In addition the cold front will still be off to the northwest likely not moving into and through the area till Thursday night and Friday. With that will continue to lean towards a drier forecast for Thursday but due to that will also lean towards the higher end of the NBM guidance for temps Thursday. Not going to go as high as the 75% MaxT prob but given the lack of rain and probably only scattered clouds (no upper level jet setting up should keep thick cirrus mostly out as well) we will probably see a nice warm up. H925 temps of 16-17 C suggest a mix down temp of around 25-26C which is in the upper 70s and can't rule out even an few areas touching 80 once again. Things actually get far more interesting Fri and through the weekend. All guidance shows a highly amplified pattern with a deep L/W trough over the eastern half of the CONUS and ridge over the western half. With a lot of Pac energy still coming down the back side of the trough(upstream), the trough will continue to dig into the western Gulf with the axis not expected to move through until sometime Saturday and northerly to north-northwesterly flow over the area through the remainder of the weekend. The first piece of energy that gets the trough developing will actually be lifting out and across the OH Valley Friday and that will have the cold front associated with it. That front will begin to move through Thursday night but given the strengthening southwest flow aloft it will likely not surge through the area reaching the Gulf around midday Friday or possibly later. This front will be the best chance for rain as it will provide the needed forcing while broad lift should help as well to get scattered showers Thursday night and early Friday. Not really anticipating much if any thunder. Forecast sndgs barley even show the area conditionally unstable if that. No real instability to tap into. Colder air doesn't really get into the area till Friday night and it could be the chilliest yet. NBM is still washing things out a little however the 4.1 MinT mean is actually in the mid 30s for some of the area. The GFS is in agreement with that as well and the CIPS extended analogs also show rather strong support for below and possibly well below normal temps this weekend and possibly starting off next week. /CAB/ && .AVIATION (12z TAF package)... VFR conditions currently over all terminals and should remain that way through the forecast. There is some fog developing off to the northwest but this should stay out of KMCB and KBTR. Once the sun comes up if there is any fog around it should quickly burn off. /CAB/ && .MARINE... Surface high pressure with cool air will continue to build into the central Gulf coast region from the north into Monday. The pressure gradient and cold air advection should maintain winds in the 15 knot range east and 10 to 15 knots this morning. This gradual decreasing trend will continue into Monday while winds gradually come around to more easterly. High pressure will shift east towards the Atlantic coast Wednesday while low pressure and a cold front advance across the Plains and upper to mid Mississippi Valley. Winds are expected to veer around to southeast to south by late Wednesday into Thursday with speeds up to 10 to 15 knots. Some showers could accompany the next cold front by Thursday or Thursday night. && .PRELIMINARY POINT TEMPS/POPS... MCB 69 40 74 44 / 0 0 0 0 BTR 69 41 75 45 / 0 0 0 0 ASD 71 40 76 44 / 0 0 0 0 MSY 68 50 73 53 / 0 0 0 0 GPT 70 44 73 48 / 0 0 0 0 PQL 69 40 73 43 / 0 0 0 0 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$