It is spread over a couple of days, heaviest looking Wed. Of course, it is the potential for training, or a storm that just sits, that would be of concern.
Indeed....if it's spread out over even a full day, it's a lot of rain, but we get this kind of rain several times a year. I need to get my yard work and weed killing done before Tuesday PM.
And it is definitely the time to clean out our storm drains.
Ask your neighbors in your area to do the same, too!
Last Edit: Mar 22, 2021 1:05:30 GMT -6 by Cheshire Cat
SKYSUMMIT President | Director of OperationsAdministrator
.SHORT TERM (Monday through Wednesday)... Biggest concern for the short term will be the potential for several rounds of heavy rain for the area. Overall current pattern has the current ridging over the southeast pushing eastward as low pressure intensifies as it moves into the Great Plains Tuesday then into the Upper Midwest/Great Lakes region on Wednesday.
Strong moisture advection from the Gulf will start on Tuesday, and PWs quickly rise to the 1.75 inch range. Looking at SPC's climatology page, would be right near record highs for this time of the year. This rich moist air will hang around through around Thursday, setting the stage up for the aforementioned heavy rainfall threat. Rainfall efficient thunderstorms along with them training is also a concern Tuesday and Wednesday. Rainfall totals are looking at the 5 to 8 inches with locally heavier amounts possible over through Thursday. A non zero severe weather threat does exist for a limited time on Tuesday. Instability would be at its greatest when storms are forecast to fire fire up with models having up to 1200 J/kg for southeast Louisiana and coastal MS. Effective shear in the 30 to 40 kt range would be able to support severe storms, but winds are predominantly unidirectional so tornadoes are not as big as of a concern. Main convective mode would be linear. Biggest concern would be straight line wind gusts and maybe hail, on top of the heavy rain threat. -BL
.LONG TERM (Thursday through Sunday)...
The secondary shortwave trough is expected to move northeast from Texas across the middle to lower Mississippi Valley Thursday and Thursday night. The associated surface low, now trending quite a bit weaker on consecutive model runs, is fairly elongated from the western Gulf coast to the Arklatex to middle Mississippi Valley region through the day with the models having differing locations. Much of the jet stream level energy that will impact this system is still over a poorly sampled area of the north Pacific, so there will likely be some additional model shifts with regards to timing, position and strength of the major features and the placement of the heavier rainfall. The one thing that remains consistent is the analog guidance continues to show a strong signal for very heavy rainfall across the central Gulf coast, but confidence right now is highest with the heavy rainfall in our area Tuesday through Wednesday night, but less so Thursday and Thursday night. The same thing can be said with regards to severe weather potential on Thursday for the same reasons, but at least a low end (5-15%) probability of severe thunderstorms within 25 miles of a point seems about right at this time. Storm total rainfall of 5-8 inches is still expected on Mississippi coast and near Lake Pontchartrain from Monday night through Thursday night.
A weak cold front will finally push through the region Thursday night, however this will only bring some drier air and not much cooler temperatures. Drier (not as wet) weather, but still some low rain chances from time to time, will persist Friday through the weekend, and hopefully additional rainfall will remain light since the area will be more than water-logged by that point with river flooding likely ongoing or worsening on some rivers at that point. A more substantial push of drier air with some cooler temperatures may finally arrive Sunday night
Freezing Days for Winter 21/22: TBD Freezing Days for Winter 20/21: 24 Wunderground ID: KLAPONCH50 - Downtown Ponchatoula NWS COOP ID: 16-7425-08 CoCoRaHs ID: LA-TG-22
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SHOWERS AND THUNDERSTORMS WILL LIKELY BE ONGOING TUESDAY MORNING AHEAD OF THE AFOREMENTIONED COLD FRONT FROM EASTERN AR THROUGH NORTHERN AND SOUTHWESTERN LA. WIDESPREAD CLOUD COVER AND CONTINUED PRECIPITATION WILL LIMIT STRONGER DESTABILIZATION ACROSS THE REGION. BUT, 60S DEWPOINTS BENEATH MODEST LAPSE RATES WILL RESULT IN 500-1000 J/KG MLCAPE. MODERATE TO STRONG EFFECTIVE SHEAR WILL EXIST AT LEAST EARLY IN THE PERIOD, BUT LOW LEVEL FLOW WILL WEAKEN WITH TIME. ADDITIONALLY, FORCING WILL WEAKEN THROUGH THE DAY AS THE SHORTWAVE TROUGH QUICKLY EJECTS WELL NORTH OF THE REGION. LOW LEVEL WINDS WILL VEER AND MORE UNIDIRECTIONAL SHEAR WILL DEVELOP THROUGH PEAK HEATING. OVERALL, WEAK FORCING WILL LIMIT STORM ORGANIZATION, AND CONVECTION MAY REMAIN SOMEWHAT ELEVATED DUE TO CONTINUAL PERIODS OF CONVECTION. NEVERTHELESS, A FEW STRONGER, BRIEFLY ORGANIZED CELLS ARE POSSIBLE, BRINGING A MARGINAL THREAT FOR STRONG GUSTS AND PERHAPS SOME HAIL THROUGH TUESDAY EVENING.
Freezing Days for Winter 21/22: TBD Freezing Days for Winter 20/21: 24 Wunderground ID: KLAPONCH50 - Downtown Ponchatoula NWS COOP ID: 16-7425-08 CoCoRaHs ID: LA-TG-22
SKYSUMMIT President | Director of OperationsAdministrator
Indeed....if it's spread out over even a full day, it's a lot of rain, but we get this kind of rain several times a year. I need to get my yard work and weed killing done before Tuesday PM.
And it is definitely the time to clean out our storm drains.
Ask your neighbors in your area to do the same, too!
here on the North Shore, we have open ditches, though cleaning is still important.luckily I am on the crown of my street (high spot) and my ditch has never overflowed....enev with 27 inches in 24 hours for TS Allison in the late 90's.
Side note..when I was 6 we moved to SoCal...and I was amazed there were no drains at all......not realizing it had an average annual rainfall of only 13 inches...so the streets were the drain.
SKYSUMMIT President | Director of OperationsAdministrator
The overnight EURO trended wetter and a little farther west with the heaviest rain, now centering directly over NOLA. Here were its rainfall totals through Thursday at 4pm.
Freezing Days for Winter 21/22: TBD Freezing Days for Winter 20/21: 24 Wunderground ID: KLAPONCH50 - Downtown Ponchatoula NWS COOP ID: 16-7425-08 CoCoRaHs ID: LA-TG-22
The overnight EURO trended wetter and a little farther west with the heaviest rain, now centering directly over NOLA. Here were its rainfall totals through Thursday at 4pm.
Good thing they just redid the drainage for the ditches for our street. We had poor drainage and while water never got in house before, it would often flood my carport in heavy rain.
60 miles southwest of New Orleans) Thibodaux, La
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This would be darn near catastrophic for New Orleans. Here's the new 48 hour HRRR run which dumps 8 to 10 inches of rain TOMORROW ALONE, over a 12 hour period, beginning around 1pm. No way the pumps could handle this, then again another 2 days of rain afterwards.
Freezing Days for Winter 21/22: TBD Freezing Days for Winter 20/21: 24 Wunderground ID: KLAPONCH50 - Downtown Ponchatoula NWS COOP ID: 16-7425-08 CoCoRaHs ID: LA-TG-22
Good thing they just redid the drainage for the ditches for our street. We had poor drainage and while water never got in house before, it would often flood my carport in heavy rain.
There is about 24 feet elevation change between me and the lake...you'd think that would be enough to ensure easy drainage....but up here we rely on a lot of small drainage canals that run through the woods...there still is street flooding, but because we don't live in a bowl like inside the levee system on the south shore, we usually only have house flooding associated with the local larger river flood plains.
This would be darn near catastrophic for New Orleans. Here's the new 48 hour HRRR run which dumps 8 to 10 inches of rain TOMORROW ALONE, over a 12 hour period, beginning around 1pm. No way the pumps could handle this, then again another 2 days of rain afterwards.
Bring back flashbacks of May 1995. Schools had even let out early. And just non stop training over the Thibodaux area and heavy flooding
This would be darn near catastrophic for New Orleans. Here's the new 48 hour HRRR run which dumps 8 to 10 inches of rain TOMORROW ALONE, over a 12 hour period, beginning around 1pm. No way the pumps could handle this, then again another 2 days of rain afterwards.
