Rains Have Arrived, Waves Not Bands, Dry, Less Humid Weekend

Yesterday, I mentioned a frontal boundary would sag over us and stall, resulting in the potential for heavy rainfall as storms aligned themselves with the upper (west to east) flow.  The front has pushed south of NOLA, decreasing our temps into the 70s with some 60s on the North Shore at 1 PM.  The 80s have been pushed down to the coast.

That frontal boundary should stall along our coast as several upper-level disturbances trigger WAVES of heavy rainfall.  I still think banding is possible and that could lead to some amounts greater than 5" as Zack showed us this morning.

Unlike yesterday, today's models have the heaviest band south of the city.  Not sure I believe that as satellite and radar look to paint BOTH sides of the Lake with heavy amounts.

I see one small wave already east of us with two more back over Texas.

I've tried to show that with the lime green dashed lines.  Until that main upper trough over the Rockies gets to our east, we'll stay in the high rain chances.  Models today sweep that trough east of us by early on Saturday.  Here's the current surface map/temps/Dew points.

WPC's forecast maps finally get the frontal boundary away from us by Saturday. Today is on top.

The middle map is for Friday morning, indicating a broad brush band of rain over south Louisiana.  IF the current setup (Waves) continues, we'll see many dry hours between the showers.  The bottom is for early Saturday AM with low pressure to our east taking the rains away from us.  I like that solution.

I know the FOX 8 graphic has Friday at 69.  IF the front were to jump back north of us, we could easily rebound back to 80-85.   What is fairly certain is that more rounds/waves of heavy rains are coming before Saturday daybreak.

Keep the rain gear handy, and let's hope the big outdoor events (Zoo-To-Do, JazzFest) get lucky.  I'm hoping this rain will wash some of the "Pollen Swarm" from the air, as Valerie & I have been dealing with watery eyes, running & congested noses for days.  This "seasonal allergy season" seems to go on forever ?!!!  Any personal remedies(Hot teas/soups, drugs!) are accepted.  Stay tuned!

Heavy Rain Potential Thursday-Saturday AM, Where Does Boundary Set UP?

Typically, after a long dry spell, Mother Nature reverses to a much wetter pattern, often causing flooding.  That appears to be shaping up for later this week as the upper-level flow becomes zonal (west to east), resulting in a cold frontal boundary stalling somewhere along the Gulf Coast.  Weak upper disturbances will bring several rounds of rainfall, and IF the band of rain aligns itself with the upper flow, training of cells could create a band of excessive rainfall.  Let's set the stage with what is happening now. An "atmospheric river" of Pacific moisture is streaking towards Louisiana.

Currently, that boundary extends from east Texas across northern Louisiana into central Mississippi. WPC's 7-day rain total map highlights a band stretching just north of us.

Clearly, RIGHT NOW, the model has the band of heaviest rainfall well north of Lake Pontchartrain.  IF that proves to be reality, we'll just have to deal with some spotty storms the next several days.  BUT, what if the band sags farther to the south?  The white colors indicate 5-10"+ totals over several days. We need to pay attention to where this boundary sets up.  I liked this graphic Hannah Gard used on FOX 8 this morning.

She indicated there will be several rounds of heavy rains with each upper disturbance.  That would allow the pumps to keep up.  Bottom line, we have the POTENTIAL for 2-4"+ of rain on the South Shore between Thursday and Friday, with higher amounts to the north.  Here's the boundary right now.

It is cooler behind the front, but the air is much drier (lower dew points).  That good feel will return for Saturday PM into next week.

Obviously, the red areas (First Alert) should be on Thursday, Friday & Saturday.  I just grabbed these graphics from the FOX 8 weather page, and they must be in the middle of updating it. Saturday PM & Sunday look great for JazzFest.  So let's pay attention to the radar over the next several days to see if this boundary of heavy rainfall reaches the South Shore. It's a given that it will reach most of the North Shore.  Finally, I wish Hannah Gard great success as she moves to Austin, Texas, for the next several years.  Her replacement (Grace Williams) will arrive next month.  Stay tuned!