Looking Back At Today’s Forecast And Forward Towards Joaquin

Hello everyone!

Active weather means evening posts and here we are with one crazy rain event in the rear view mirror and hurricane Joaquin looming in the distance. You will find a look back at how the forecast did for today and an objective, no hype look at some of the possible scenarios for Joaquin later this weekend and into next week.

Reflecting On Today’s Forecast

Preliminary Rainfall Totals From NWS Gray For Today's Rain
Preliminary Rainfall Totals From NWS Gray For Today’s Rain

A look at the NWS preliminary rainfall map shows a pretty good soaking for much of Maine and New Hampshire. The forecast was for widespread 2-4″ (dark green and yellow) with isolated 3-6″ amounts (yellow, orange, and red). Overall, it wasn’t a terrible forecast. I mentioned the greatest likelihood for the heavier amounts would be near the coast which they were but the big surprise was just how much it rained in some spots. the purple areas reflect where I was too low in my forecast amounts. In Portland most notably and likely elsewhere too, those heftier totals caused some big problems. The lesson: never underestimate the power of insane moisture and a slow moving front (PWATS (available moisture) were approaching or hitting +4 Standard Deviations for those with a stats background). When looking at this forecast, I was reminded of rain events earlier this month where I busted too high twice and that thought was certainly in my mind as I was coming up with the forecast. It was good to be reminded sometimes more does fall than you expected.

Looking Ahead To Joaquin

A Look At The Large Scale Players In Joaquin's Track. Map Credit: Weatherbell, Additions By Me
A Look At The Large Scale Players In Joaquin’s Track. Map Credit: Weatherbell, Additions By Me

Looking out towards Joaquin, the forecast is *surprise!* very uncertain. Instead of go into details here, I want to explain a few of the basic scenarios, why they could/could not happen, and what the impacts might be here in Maine and New Hampshire.

A look at the large scale pattern surrounding Joaquin shows a complex series of highs and lows each wanting to pull the storm in different directions. a strong upper low over the SE US wants Joaquin to move west while Ex-Ida (which could come back from the dead) wants Joaquin out to sea with it. Add to that tremendous blocking over Canada and you have what could be a nasty situation for those to our south.

Scenario 1: Mid Atlantic Landfall

18Z GFS Depiction of A Mid Atlantic Landfall
18Z GFS Depiction of A Mid Atlantic Landfall. Map Credit: Weatherbell

This is the most likely scenario based on an analysis of upper air features and is supported by every single model I can find except for the Euro and a few renegade ensembles. In this scenario, a developing upper low over AL and GA would suck Joaquin into its warm embrace causing it to turn sharply left into the coast. This would bring extreme impacts to the Mid Atlantic region and for those reading from Philly south to Charleston, check with your local NWS office or favorite local weatherperson for details. I will focus on possible impacts north and east of Boston.

18Z GFS Depiction of Remnants Bringing Heavy Rain To Maine and New Hampshire. Map Credit: Weatherbell
18Z GFS Depiction of Remnants Bringing Heavy Rain To Maine and New Hampshire. Map Credit: Weatherbell

Impacts up here in Maine would likely be delayed until Monday afternoon/evening through Monday Night when a round of heavy rain would move through as the remnants moved north. Heavy rain and coastal flooding would be the biggest issues should this scenario pan out as indications are Joaquin’s tropical moisture could once again bring Precipitable Water values (available rain/moisture) to levels we saw today.

Scenario 2: Out to sea

12Z Euro Showing Sprawling High Pressure Pushing Joaquin Safely Out To Sea. Map Credit: Weatherbell
12Z Euro Showing Sprawling High Pressure Pushing Joaquin Safely Out To Sea. Map Credit: Weatherbell

There is only one model showing this solution at the moment and it is the #1 model, the euro. While this solution appears unlikely as the pattern and every other model out there supports a landfall, it can’t be 100% discounted yet as the Euro has a pretty good track record. In this scenario, there would be no impacts to New England.

The bottom line here is to watch and wait. For those who know folks in the Mid Atlantic, give them a heads up and tell them to listen to local NWS offices and to heed any orders from local officials. There is a strong indication that the storm does make landfall and bring us eventual impacts in the form of heavy rain. I’ll have more updates in the coming days as this develops.

One last note, please don’t believe for a minute any one model solution or doomsday graphic someone may post. Uncertainty is still high here. That being said, this does have the potential to be very serious for the Mid Atlantic. Comparisons to Sandy’s surge in terms of impacts are not unfounded for VA beach and DC. The Capitol Weather Gang has a good update to refer to for the Mid Atlantic threat and takes a similar path to my update outlining potential impacts and scenarios.

I’ll have another update on tomorrow’s weather in the morning and will likely be back tomorrow evening for another Joaquin update.

-Jack

Torrential Rain And Flash Flood Threat Today, Watching Joaquin Very Closely

Hello everyone!

Today will feature the passage of low pressure along a stalled front which means very, very heavy rains for pretty much the whole area. Humidity will continue to be very high and temps will be mainly in the 60’s.

5:45 AM Radar. Map Credit: COD, Additions By Me.
5:45 AM Radar. Map Credit: COD, Additions By Me.

As of 5:45 this morning, we have a surface low over the PA/NJ/NY border with lots and lots of heavy rain out ahead of it. Bands of heavy showers are moving off the ocean ahead of the main bout of precip which will enhance totals along the coast. Heavy rain will continue to move through and impact the area through early afternoon. Flash flooding is a real threat with this storm and the potential for 1-2″ per hour rain rates has been highlighted by the WPC in a MD this morning (that’s extra credit reading if you wish and will make my nerdiest discussion look like a kindergarten textbook). What you need to know is that it will rain hard today, for most of the day. The original forecast of 2-4″ widespread with some 3-6″ looks alright though totals may be towards the lower part of that especially up north.

Looking ahead towards Joaquin, if the current solution portrayed by many models pans out, this is a really serious situation for the Mid Atlantic. The upper level pattern favors a track into the coast however that could change. For Northern New England, we are, as usual, much more interested in the remnants which could bring another few inches of rain to our area early next week. I’ll have more updates on that later in the week as the forecast becomes more clear.

-Jack

Very Heavy Rainfall Threat Tonight And Tomorrow, Sneak Peek At Joaquin/Possible Late Week Trouble

Hello everyone!

Special update tonight to cover what is shaping up to be an extraordinary rainfall event for Maine and New Hampshire. Will this be historic? Unlikely. WIll it be devastating? Probably not. Will it be a big headache? Absolutely. Let’s dive right in.

2015-09-29_18-43-48
6:30 PM Radar

Current radar shows a broad area of heavy rain over the Mid Atlantic associated with developing low pressure and another batch of rain along and ahead of a cold front sagging south. Rain is already moving through western ME and NH and is rather heavy in spots and this will continue through the evening increasing in coverage and intensity.The threat of heavy rain has begun.

12Z GFS Model Idea Showing Torrential Rain  Tomorrow Map Credit: Weatherbell, Additions By Me.
12Z GFS Model Idea Showing Torrential Rain Tomorrow Map Credit: Weatherbell, Additions By Me.

The low currently over the Mid Atlantic will move NE along the front and end up in the Gulf of Maine tomorrow. The above image shows the position of the low at 2PM tomorrow afternoon and precip totals from 8AM to 2PM. While I think this model is a bit overdone with its 3-4″ in 6 hours idea, it goes to show a larger idea of very heavy rain in the morning and early afternoon tomorrow. Flash flooding is definitely a threat with this torrential type of rain so be prepared for that threat on the AM commute tomorrow.

Total rainfall looks to be in the 2-4″ range for most with isolated 3-6″ amounts where the most intense storms pop up. The greatest likelihood for something like this to happen is south of route 2 closer to the low and the front.

The front briefly moves offshore Thursday for a period of nice(ish) weather as the sun could make an appearance but NE winds will likely be gusty so it will still feel a tad raw.

Looking ahead towards the weekend, the front appears to move back north which would likely provide focus for another round of rain Friday into Saturday at which point things get very interesting with Tropical Storm Joaquin. At this point in time it looks like the bulk of the impacts stay to our south as an upper level low pulls it into the Mid Atlantic though this is still far out and, as usual, can and will likely change. I’ll have more updates on that in the coming days.

Regardless of Joaquin’s involvement in the latter part of the forecast, the next 24 hours is shaping up to be a wet one so that’s where our attention will be focused for now.

I’ll have another update in the morning.

-Jack

Scattered Showers Today As Sizable Rainmaker Moves In

Hello everyone!

Today will feature mainly cloudy skies with some scattered showers from time to time. While it won’t be a washout, keep the umbrella handy as a tropical airmass moves in creating the potential for heavy rain in any showers that do form. Humidity will be nearly unheard of for late September with dewpoints rising into the low to mid 60’s. Temps will be warm as well with highs ranging through the 70’s with some upper 60’s possible at the coast and up north.

Shown here is the HRRR courtesy of Weatherbell showing one idea as to how scattered showers could play out today.

Tonight and into tomorrow we get a total deluge as tropical air is pushed up and over a front that will be draped across the area. The precise location of the front will dictate exactly who sees the highest totals but a widespread 2-4″ is likely with locally higher amounts to 5 or even 6″ possible under any convective elements that develop and train. Lower amounts of 1-3″ are likely along the international border. You may have heard of tropical storm Joaquin moving north this weekend, I’m watching it carefully but am focusing on tonight and tomorrow’s rain threat now. Keep in mind, the 2-4″ with locally higher amounts is through Thursday and doesn’t at all include this weekend’s rain which I will have more details on later in the week. With this much rain, flooding is definitely a concern and flood watches are up for everyone except far northern areas.

Be sure to stay updated on this event and take appropriate actions for heavy rainfall. I’ll have another update tomorrow morning at the latest and if conditions warrant, tonight. Stay tuned to the NWS and local media for more info.

-Jack

One More Nice Day Before Much Needed Rain

Hello everyone!

Today will feature increasing clouds and warmer temps with highs ranging from the low 70’s north to the low 80’s in interior SNE. Enjoy this one last day of nice weather because heavy rain looks to arrive tomorrow afternoon/evening and stretch into Wednesday. Coastal areas are in a moderate drought so this isn’t all bad news. More on that threat tomorrow.

-Jack