Tropical Cyclones!

In the wake of Hurricane Irene, we have two new developments in the tropics. The National Hurricane Center has indicated an area of interest just east of the Yucatan Peninsula, noted here with the orange hashing

 They indicate it has a 30% chance of becoming a tropical cyclone but both the European model and GFS model that i have looked at indicate it's development into a tropical depression or a tropical storm over the next couple of days.

The reason I would favor this idea is because of the gulf of mexico. Tropical cyclones feed off of warm ocean waters and the gulf is a prime location for storms for this reason. This tropical wave depicted above is projected to move into the gulf where i suspect it to feed into those waters and develop. It may not become a hurricane but it will certainly produce rain for the upcoming weekend so people making plans for Labor Day around the gulf need to heed to warnings or watches about this storm.


2ND STORM: Tropical Storm Katia is now in the Central Atlantic with 60knots sustained winds. Conditions are favorable for Katia to develop into a strong Hurricane but it's threat to land is still uncertain. Models at the moment have trended for Katia to continue towards the east coast but then turn Northwest and Northward over the next week or so.

The reasoning for Katia to turn like that is the upper level patters of the atmosphere. The mid latitude jetstream can have a profound impact on these tropical storms, almost "steering" them northward. It looks like a trough that moves over the east coast kind of pulls the storm northward and it joins into the mid latitudes. This would be good thing for the east coast after they got pounded with heavy rains and subsequent flooding from Irene.

I'll have another update on the tropics in a day or so, I hope

On a side note, I was shown an article by FOX news the other day about how the US doesn't need a National Weather Service anymore and that private forecasting companies and media like The Weather Channel are far better at forecasting than the NWS. This is preposterous on so many levels, most importantly, where do those private companies and the media get their information? Oh yeah, the NWS, who runs the models and talks about conditions hourly. I can't believe FOX even allowed this opinion article to be published. Pathetic

http://www.foxnews.com/opinion/2011/08/27/do-really-need-national-weather-service/

Have a great work week!

Will a La Nina Winter Return?

La Nina La Nina, oh where art thou La Nina. While many people would have hoped La Nina was in our rear view mirror, after experiencing a dismal winter and an even worse Spring, it looks like we won't be able to drive fast enough away from her. The Climate Prediction Center is the major government body in the US that predicts our ENSO cycle (El Nino Southern Oscillation) and they have just recently posted a La Nina watch for this upcoming winter. So if you didn't enjoy this past winter or Spring, you may consider taking a nice long trip to Mexico for a break or two.

For those of you who would like to know a little more about La Nina, read on

La Nina is declared when the Sea Surface Temperature in the Central and Eastern Pacific averages .5 degrees Celcius below normal for 3 consecutive 3 month intervals. Here is a graphic that I hope explains this more.

This graphic shows the last La Nina we went through this Winter and Spring. The declaration of a La Nina occurs with temperatures taken from the 3.4 region shown in the 2nd box above. I'm not sure why it has to be this region but I know it is.

These are the regions here with the 1+2 box nearest the South American Continent.

You can see in June and into July we we starting to just average positive sea temperatures and now in August we have retreated back to negative anomalies. Model projections that are run by the Climate Prediction Center as well as many other agencies around the world are beginning to show the return of La Nina this winter or we enter into a Neutral phase, between El Nino and La Nina.

The average of these model runs is shows to hover near neutral conditions and not "double-dip" to La Nina. But if current conditions continue, I wouldn't be surprised to see the average of these models continue to inch closer to La Nina conditions. The CPC's own model is also run numerous times.

Their's clearly shows a double-dip La Nina scenario predicted.

While this last winter wasn't the Snowmaggedon projected by many media outlets, La Nina winters do typically give Washington cooler and wetter weather patterns. I will be anxious to see what the next outlook says.

(How La Nina forms: Trade winds in the tropics move from the east to the west, contrary to here in the mid latitude areas where the winds move from West to East. During a La Nina episode these trade winds are strong and move warm ocean waters on the surface of the Pacific to the West. This brings upwelling to the eastern Pacific (cool, deep ocean water moves up) and this is why we register colder sea surface temperatures. The atmosphere and it's circulations are affected by this surface temperature movement in a variety of different ways and current research is still being done today on how these changes affect weather in Washington and all along the West Coast. It is a challenging research area since the period of oscillations are so large and we have only approximately 60 years of La Nina/El Nino records)

Summer Rain

I just took a look at the Global Forecast Model that the National Center for Environmental Prediction runs and it doesn't look too good for the Northwest over the coming week. Two upper level lows, associated with clouds, rain, and cooler weather will be making their way into the Northwest, with their eyes set on Washington.

It looks like clouds will dominate Wednesday and Thursday and there is a decent chance of rain for the beginning part of next week.

Just a short quick forecast tonight

Summer in the Northwest!

For the past two weeks or so, it seems as if the Northwest has grown out of it's cool Spring and jumped right into a decent summer. Being down here in Southern California I haven't checked out any of the weather up there lately but I did this morning.

It looks like the upper levels of the atmosphere over the next couple of days will be "weak". What I mean by that is the airflow will not be as strong at the 500mb pressure level and  there doesn't appear to be any trough (cooler and wetter) or ridge (warm and sunny) that parks itself over the area.

This is a typical summertime phenomenon as it means there is a weak onshore push in the mornings and the afternoon heating of the atmosphere will clear out the clouds for a partly sunny or mostly sunny afternoon.

That's why the forecast for the next week calls for highs in the mid to upper 70s for almost 7 days straight. Almost unheard of for the Northwest. I haven't looked at longer range models (out 15 days) but I wouldn't be surprised to see this pattern continue.

Enjoy the sunny weather up there Pacific Northwesterns! And remember, If it's sunny there, it's always a little more sunny down here in So Cal. ;)

I'll have another blog in a few days detailing some local California weather and what I'm learning at the National Weather Service

Next Tropical Storm?

UPDATED AUGUST 4th 10:00 AM PST

TS Emily is now located just South of the Dominican Republic moving WNW at 5mph, quite slow. The updated projected path still takes it just East of Florida but with now direct impact on the state. Still, rain and wind will most likely affect the peninsula and the Keys with Tropical Storm force.



UPDATED AUGUST 3rd 2:00PM PST

I have just looked at some of the more recent forecasts and it looks like Florida will be glanced by the storm. It is now officially Tropical Storm Emily and is located just Southwest of Puerto Rico. A recent radar image from Puerto Rico shows just part of the storm

Heavy rain, wind, and possible flooding will accompany the storm as it is crossing over the Caribbean islands. It's current forecasted track will take it just east of Florida but will still likely impact the state with rain and wind.

It appears likely that it will not intensify into a Hurricane by morning Saturday, where it is just east of the Florida coast. Will update on any more notices

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Current satellite images show a tropical "wave" in the western Atlantic near the Northern Windward Islands and Leeward Islands.

The National Hurricane Center has given it a 90% chance for tropical cyclone development over the next 48 hours. This could mean very short notice for Tropical Storm warnings in the Caribbean group of islands. GFS model runs done last night bring the low pressure system just East of Florida by August 6th, 6 days out

 But another model run, the ECMWF (dont worry about what the letters mean) showed almost no development by day 6 and the storm dissapating. There is plenty of uncertainty with the storm as the model run done around midnight PST last night (06Z) showed this

With the low WELL off the coast and not a threat to the US coastline.

At the moment, with no surface circulation, the tropical wave is not a depression but is likely to form into one with favorable atmospheric conditions over the next 48 hours. Air Force Hurricane Hunters will monitor the progression of the storm for the next several days.

Updates to Follow