Sunday through Monday will be quite busy. The pattern is setting up for a very heavy rain event and we will likely need to issue Flash Flood watches for much if not all of the area. As the upper low begins to lift across the Southern Plains we will quickly move under increasing southwest flow aloft. Multiple favorable parameters will be coming together to support about a 6 to 12 hour time frame of heavy rain somewhere over the central Gulf coast. Once again divergence aloft will be optimal (possibly even better than today). This will combine with a strengthening LL jet which will be pumping in rich h85 theta e air of near 340K. H5 winds will also be increasing with 50 to 65 kts moving through. Rich moisture will be in place with PWS possibly approaching 2.25". One more rather concerning issue is that there will be instability to work with as well. Showalters values will approach -5C and the K index could actually be abv 40C. This indicates that we will see a good bit of thunderstorm activity. The combination of all of these features suggest very efficient storms. WPC already had the area outlooked with widespread 3 to 6 inches and as long as things set up over the area this will be fairly easy to achieve and some areas could easily see much higher values, probably topping double digits. Locations and timing is still uncertain and the highest rainfall totals will be very dependent on placement of features and could easily be over western sections of the outlook area near BTR or could be all the way over to coastal MS. Hopefully over the next few days we can get a better idea of where the heaviest rainfall may occur.
If that was not enough given the amount of forcing, shear, and instability we can not rule out embedded strong to severe storms. Even tornadoes are possible especially given the amount of shear expected.
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Post by huskiesdelabasin on Mar 30, 2017 20:22:08 GMT -6
i gave you a thumbs up but not because i like at all what you said but because you answered and you guys know your stuff lol. well hopefully it wont get bad and the rain goes where its needed. i dont need it lol im going have mud for days.
Post by huskiesdelabasin on Mar 30, 2017 22:05:03 GMT -6
this is what Dr Greg Forbes wrote on his facebook page about sunday. tor of 4 dont sound to great. SUNDAY 4/2
Scattered severe thunderstorms and locally heavy rain in southeast TX, south and central LA, south MS, spreading overnight into west-central and southwest AL, west FL panhandle. TORCON - 4 upper coastal TX and south LA; 3 rest of area. A chance of an afternoon and evening severe thunderstorm in southeast KS, east OK, northeast TX, north LA, AR, southwest MO, northwest MS. TORCON - less than 2
...SUMMARY... Organized severe thunderstorm activity is possible across parts of central and eastern Texas into portions of the lower Mississippi Valley Sunday into Sunday night, accompanied by a risk for severe hail, potentially damaging wind gusts and a few tornadoes.
...Synopsis... Models indicate that an evolving impulse within a southern branch of split mid-latitude westerlies (likely west northwest of the Texas Big Bend region at 12Z Sunday) will accelerate east northeastward during this period. Considerable spread is evident within the model output concerning the speed at which this occurs, with the more progressive solutions suggesting that an associated negatively tilted trough axis will at least reach the Sabine Valley by 12Z Monday, while the slower solutions lag to the west, across parts of the Texas South Plains into lower Rio Grande Valley.
In general, though, it appears this feature will support the development of a significant surface low within surface troughing, migrating northeastward out of the Mexican Plateau/lower Rio Grande Valley region. This also appears likely to be favorably timed with an increasingly substantive return flow off the Gulf of Mexico, which probably will include surface dew points in the mid 60s to around 70 F. In the presence of relatively steep mid-level lapse rates, guidance is suggestive that this may contribute to boundary layer based CAPE on the order of 2000+ J/kg within the warm sector, inland of mid/upper Texas coastal areas. Destabilization may coincide with strengthening of lower/mid tropospheric wind fields, including 30-50 kt (southerly) at 850 mb and 50-70 kt (west southwesterly) at 500 mb.
...Southeastern Plains into northwestern Gulf coast region... Aforementioned warm sector environmental conditions, including large-scale forcing for ascent, appear favorable for organized severe storm development Sunday into Sunday night. This could include discrete supercell development (with attendant large hail and tornadic risk) prior to, and in advance of, an evolving mesoscale convective system that may be accompanied by swaths of potentially damaging wind gusts. Uncertainty associated with timing of the evolving system is tempering severe probabilities somewhat, but highest probabilities at this time appear to exist across parts of central/eastern Texas into parts of western/ central Louisiana Sunday afternoon and evening.
Hydrologic Outlook National Weather Service New Orleans LA 1055 AM CDT Thu Mar 30 2017
...Rises on area rivers may lead to minor to moderate flooding by early next week...
A series of strong weather disturbances, one moving through the Mid-Gulf region this morning, and a stronger one expected by late Sunday evening into early Monday, is expected to bring moderate to heavy rainfall. These disturbances are tapping into unusually warm and moist air for the early spring.
Cumulative rainfall totals between the two weather events could average close to 7 inches by Monday. If this much rainfall does occur, then some minor river flooding will result, mainly on the northshore rivers including the Amite-Comite, Tangipahoa and Tchefuncte and Pearl Rivers and across the Mississippi Gulf Drainage, including the Wolf, Biloxi and Tchoutacabouffa and Pascagoula Rivers.
Persons living close to the area rivers and streams should stay aware of the weather situation through Monday and be prepared to take action in the event flood warnings are issued for your area.
This Hazardous Weather Outlook is for portions of Southeast Louisiana...South Mississippi and the adjacent coastal waters.
.DAY ONE...Today and Tonight
No hazardous weather is anticipated at this time.
.DAYS TWO THROUGH SEVEN...Saturday through Thursday
Strong southeast and south winds are expected to begin affecting the coastal waters as well as inland areas Saturday night with the strongest wind speeds expected Sunday and Sunday night. This may lead to wind advisories for some land areas and small craft advisories or gale warnings for marine areas.
Minor coastal flooding will be possible Saturday and Sunday. Tides are expected to rise to 1 to 2 feet above normal during the same time as spring tides. Areas normally prone to minor coastal flooding should observe the highest water conditions during times of high tide which will occur around and after noon each day.
The main issue associated with the next system is expected to be long periods of heavy rainfall that could lead to localized flash flooding. Strong and severe thunderstorms are also possible Sunday into Monday morning.
.SPOTTER INFORMATION STATEMENT...
Spotter activation will be possible Sunday into early Monday.
AREA FORECAST DISCUSSION National Weather Service New Orleans LA 401 AM CDT Fri Mar 31 2017
.SHORT TERM... Post frontal air mass is steadily moving into the area from the west and northwest. Satellite imagery indicates the same in the mid/upper levels with much drier air aloft progressing in. The combination of dry air and high pressure subsidence will yield mostly clear skies today. Upper ridge already moving in will increase column heights and thus allow for temps to moderate considerably. This warming trend will continue into Saturday as the ridge spreads across the entire southeastern United States. For forecast temps, used a blend of MEX and MOS guidance. Those temps will be nearing record highs on Saturday.
.LONG TERM... The potential for a widespread heavy rain event Sunday night is looking more and more plausible. An upper low, that is currently spinning over the desert southwest will track southeast along the US/Mexico border through Saturday night. This low is expected to then take a more east and then northeast track as is moves across Texas Sunday. This will put strongest lift and diffluence aloft over the central Gulf Coast. Gulf moisture will surge northward into the region ahead of the approaching system Sunday evening and overnight. Looking at model soundings, atmospheric moisture levels will be EXTREMELY HIGH with precip water values near 2" as convection moves across the CWA. For reference, the 90th percentile for this time of year is less than 1.5". So hitting the 2" mark is well into record territory. Seeing numbers like that definitely increases the concern for a heavy rainfall event somewhere around the general region of SELA and/or southern Mississippi. Widespread 3-6" looks likely with isolated amounts possibly reaching upwards of 8-10". Those amounts are roughly over about a 12 hour period. More than likely will be issuing a Flash Flood Watch as the event nears.
Tide levels look to be an issue as well with the weekend system as deep fetch strong winds bring water levels higher into the weekend along with spring tide fluctuations within the same time period.
A return to warm temperatures and no rainfall is expected Monday through the middle of next week.
10 - 14" in a 12 hour period is what can cause significant flooding on the north shore again. I really hope we don't see that.
I'm sure it would cause some rather significant flooding on the Comite and Amite as well. Obviously not on the scale of August but there would be many homes that flooded in March and August that would flood again if this event transpires. Three times in one year - I just can't fathom.
Looking at model soundings, atmospheric moisture levels will be EXTREMELY HIGH with precip water values near 2" as convection moves across the CWA. For reference, the 90th percentile for this time of year is less than 1.5". So hitting the 2" mark is well into record territory.
coffeecups: I'm still lurking at the coming weather!
Apr 17, 2017 16:44:08 GMT -6
coffeecups: WOW! My patio was dry when I got home.
Apr 16, 2017 18:22:16 GMT -6
coffeecups: Came home to Harvey from Slidell. Had a little rain here and there. There was no rain in Slidell when I left at 3:30pm. While in NO EAST, I saw where it looked like it was storming around Covington going towards Slidell. Wet but no rain when I got home
Apr 16, 2017 18:21:07 GMT -6
coffeecups: I will eat some strawberries on my cruise in early May---just a few of course, as long as I stay away from my better half.
Apr 13, 2017 20:39:35 GMT -6
SKYSUMMIT: Yea, had a good bit of strawberries. Did NOT go to the fest though.
Apr 12, 2017 19:48:32 GMT -6
coffeecups: Sky, did you enjoy the strawberries?
Apr 12, 2017 18:43:30 GMT -6
SKYSUMMIT: yea, we're in a quiet lull right now
Apr 10, 2017 21:19:12 GMT -6
coffeecups: At least with the tropical forecast we have more to go on than fantasy.
Apr 9, 2017 18:00:26 GMT -6
coffeecups: Unfortunately for me, strawberries are a widower maker!
Apr 8, 2017 11:46:43 GMT -6
SKYSUMMIT: Man it's gonna be a nice weekend! If you're looking for something to do, head over to the Ponchatoula Strawberry Fest!
Apr 5, 2017 21:35:02 GMT -6
coffeecups: Are you getting like me?
Apr 5, 2017 11:08:26 GMT -6
wsmith0306: Can't believe I've never noticed this before. I must be getting old or blind. or both!
Apr 4, 2017 8:06:37 GMT -6
coffeecups: It felt cool this morning. Very nice weather!!!
Apr 4, 2017 7:13:20 GMT -6
coffeecups: Mary protected me again.
Apr 3, 2017 7:18:35 GMT -6
SKYSUMMIT: LOL wsmith....it's just a little chat box
Apr 1, 2017 8:53:27 GMT -6
wsmith0306: What's this "shoutbox" thing all about? I'm at work, so I'm whispering right now. Hope that's allowed :).
Mar 30, 2017 12:38:44 GMT -6
coffeecups: I'm hoping that I don't see any 'rare' rain events here.
Mar 29, 2017 7:39:51 GMT -6
coffeecups: ps I guess the memory of that snow is probably the only winter that I will get.
Mar 25, 2017 7:16:52 GMT -6
coffeecups: Somewhere around 1956 and 1958 it snowed so much that I thought I was in a blizzard. Of course I was only a child then, but the memory of that has NOT been met or surpassed.
Mar 25, 2017 7:15:41 GMT -6