Flirting with the Monsoon ..and some thoughts on summer 2018

[Silas_Sancona]

  On another hot Saturday evening, it is interesting to think that at the same time just last week, it was cloudy, humid and only 78F, compared to 95F out atm. That coming after a very good ( and unexpected) downpour earlier in the day, thanks in part to the squeeze play between the remnants of former Hurricane Bud, and an approaching upper level low moving N.E. from northern Baja. 

While most of the valley ( inc. Phoenix proper ) completely missed out, and thus continue the streak of rainless days since March ( 102+ and counting) we received a healthy .50-.75" which, in other places, might not seem like much.. but is practically un-heard of here, esp. in June. Rain during what is typically the hottest calendar month here is rare enough that had Sky Harbor received anything above .01", it would have been only the 3rd time rain was recorded there on June 15th since 1900.

Tucson, which won the June rain lottery, got nearly an inch of rain, with many places across S.E AZ exceeding 1.25-1.50" of rain.. some areas down south also saw hail and a funnel cloud reported Saturday afternoon.. a tantalizing hint of what might lie ahead as this years' Monsoon season gets under way??, ..perhaps 

 After what many people considered one of the nicest Father's day weather in the area, in years last Sunday, it was back to our typical 105-110F hot and dry weather this past week.  Interestingly, while hot enough, it hasn't been as hot as both 2017 and 2016 at the same time.. when we were exceeding 114- 120F. While there is plenty of summer to experience our brand of blast furnace heat, once dew point and humidity levels start increasing on a regular basis, it becomes harder to reach 110 and above, even if the extra moisture makes it feel almost as hot. Anyway.. going forward, Was our, out of the blue, June downpour a hint of what forecasters have been suggesting looks to be a promising summer rainy season across the South West.. or, just a tease.. Some thoughts.. 

No doubt, the region REALLY need a break... Phoenix has only received 1.00" of rain since last August.. supposedly the driest period recorded here, EVER.. Many of the Nat. Forest areas across the state are closed to the public due to how severe the regions drought has been, and extreme concern about big fires, which.. so far, we have been lucky to avoid. Interestingly, it is the drought itself that holds clues to what might happen this summer..

S.W Monsoon season. A short breakdown :
When looking at the potential of a "wet" monsoon pattern across the region ( N.M., AZ., CO., W/TX., NV., CA. BCN/BCS, Sonora, Mexico) , the following factors are considered important, at least according to on-going research:

Dry winter / spring = potentially wet summer/ above average rainfall. Less winter snow pack melts faster, thus the sub tropical high that sets up over the 4 corners,and also gets the pattern going can establish itself faster. 
Wet winter/ spring ( inc. lots of snow) the exact opposite according to what data has been studied.. 

Cool water off the Pacific side of southern Baja, warmer water temps in the Gulf of CA.. this influences the land/ sea differential of temps. which helps induce "Gulf Surges" up into AZ / S.E. CA. We've had a couple thus far.. no clouds / rain with the one this morning..

ENSO.. an interesting factor.. and one that isn't yet fully understood. While one would imagine a raging El Nino would equal above average rain here during the summer, such conditions may actually lead to a late and drier monsoon. A "neutral" or slightly La Nina state seems to produce more favorable outcome. Again though, research into the influence of ENSO continues... and every cycle produces different results. 

One big signal that can help produce lots of rain across the southwest, that is tied to ENSO, is the Hurricane season in the East Pacific itself.. More storms, especially if they stay closer to Baja, or run up the Gulf of CA and/ or slam into Northern Sonora.. or unwind just offshore of S. CA. can cause the kind of flooding events Arizona and other parts of the region have seen in the past. 1984 and 2014 are two notable examples in Arizona.  

There are other factors, such as what influence moisture from the Gulf of Mexico / Caribbean basin plays.. position /strength of the Bermuda High, and how wet the southern plains were/ are going into the summer, etc.. that are looked at as well. Would take too long to dive into, so.. my thoughts going forward.. and remember, this they are just that.. Feel free to add any thoughts of your own..

E. Pac. / Atlantic Hurricane season:
 
If Aletta and Bud were fast and furious warning shots, i think the calls for a very active season across the East Pacific are spot on.. in fact, there are two potential systems being watched south of Mexico atm, and at least 3 more suggested to form by July 9th by some Wx models. if that happens, that would be at least 9 storms, before mid July.. Doesn't mean they'le ll be named.. then again..   Maybe a close approach or two off S. Cal this year also.. more possible summer rain events, esp. if some of the bullish long range models ( which have only gotten more aggressive since i started looking at them in April) for September and October pan out. Hawaii should also keep an eye out.. Central Pacific is also looking at an active season ahead..  May be a really good summer for the Surfing crowd along S.Cal beaches as well... 

Atlantic looks quiet, and may stay quiet for awhile.. SSTs in the primary region for formation off Africa  are currently the coldest they have been sine at least 1985 and don't look like they're going to get much warmer anytime soon. Bermuda high looks strong this year and may quickly hurl many easterly waves that form this summer across the ATL basin / Caribbean toward/ over E. Mexico. That being said, things can change, and it only takes one storm forming near FL. the east coast, or in the Gulf of Mexico to cause trouble.. Obviously, don't let your guard down.. On the other hand, the region needs a break after the chaos of last year. Overall rainfall may be below average across S. FL and the Caribbean, at least until September or October.. 

Heat:
Thinking most of the country is going to feel it most of the summer ahead.. though we in the southwest may get some degree of a break ( thanks in part to a potentially wet monsoon.. or the continuation of the weird pattern we have been having lately)) Atm, the east looks to bake going into the 4th of July.. then is spreads west..  After what has been a cooler start to summer, July and August look hot for CA,  and also Ore. and Wash. state, which may also see below normal rainfall at the same time.. We'll see what happens, not quite convinced yet. 

S.W. Monsoon season:
If the pattern ahead follows what the near and longer term forecasts have been suggesting since April.. and continue to stay focused on it, it is possible that the region may see a wet summer.. one that is badly needed.  While rainfall that falls here at this time is often spotty, with some areas getting soaked and others remaining hot and dusty.. the continuing thought of above average rainfall for the July- October season across the state and for western New Mexico/ S. Cal. paints a brighter picture that everyone will get something..

Many of the + factors for above average rainfall i touched on above are looking good this year, so.. we'll see. Nothing is a slam dunk.. Ideally, id like to see a really wet Monsoon.. on par with some of the wettest on record ( '84, 2014, etc).   If the ideal set up..does indeed set up, and a good deal of moisture is thrown our way from the Gulf of Mexico, instead of being shoved south into Central America, or north into the Plains.. it could end up being a classic season here.. Throw in solid moisture surges from the East Pacific / Gulf Of CA., especially later on and ..well, we'll see what happens..  At minimum, Hopefully this year isn't a bust like last year.. and we get more than 3 weeks of enjoyment out of the entire season..

And lastly, the hints surrounding a possible + ENSO

El Nino / La Nina:

Will admit that i have been on the fence on this since some were suggesting the turn toward another potential El Nino earlier in the year..Still not fully sold yet.. but can't not see the obvious hints that have started to emerge over the spring.. Still, i want to see a few more things before i throw both feet on board..  While active now, i'll be watching to see how the East Pacific Hurricane season ends.. How the Atlantic behaves.. and how Sea Surface Temperatures rise.. or don't off Mexico and CA. I'll also be watching the fishing and birding reports over the summer for rare stuff that might start showing up off S. Cal. Locals know what i mean..

Even so, a full blown El Nino isn't a slam dunk for lots of winter rain for CA.. as everyone knows from the last busted forecast.. Every cycle is different so again, we'll see what happens.. maybe this one will be a classic, like '97 or 1982 / 83.. some of the longer term models ( Nov - Feb ) seem to hint at the possibility.. then again, they did this back in 2016. 

Regardless, it's summer.. Days start getting shorter from here on out.. enjoy it. 

Hopefully it is wet



-Nathan 

** For reference, access to long range Wx models are located on the CPC's NMME page.  Pretty sure they are updated around the 1st of each month. 


 

[mdsonofthesouth]

El Nino for me means cooler temps and 4 in 7 chances for big snow or at the very least more cold rain. Not looking forward to this winter as I was hoping for a break.

Edited June 25, 2018 by mdsonofthesouth