West Coast Wind Blog: Models bickering about Baja tropical storm

by Mike Godsey, mike@iwindsurf.com

Ever wondered why do you see really vague forecasts like this Baja Forecast today?

“Some models have is just wobbling around south of Los Cabos and dying. But the ECMWF European models, which does a very good job on storms, has the unnamed storm coming close enough to Cabo to send significant rain to Baja’s East Cape especially in the mountains.

If this happens we could see GUSTY SE winds to the mid 20’s and significant rain especially towards Los Barriles. If you are camped in an arroyo be ready to move fast and follow the forecasts carefully. Remember that even if it does not rain on the coast heavy rain in the mountains can send a sudden mass of water down arroyos.”

This animation shows how radically different the GFS and ECMWF forecasts are for the next few day regarding this tropical storm.

West Coast Wind Blog: Still a chance unnamed tropical depression may impact Baja’s East Cape.

 

by Mike Godsey, mikeATiwindsurf.com


Here is yesterday’s blog about this storm

This animation show todays imagery of the storm at dawn Thursday, Nov. 14, 2019.

As you can see there is a hint of it developing a circular rotation but so far it looks very unlikely to become a hurricane. Still, there is significant rain and winds in this system. Some models have is just wobbling around south of Los Cabos and dying. But the ECMWF European models, which does a very good job on storms, has the unnamed storm coming close enough to Cabo to send significant rain to Baja’s East Cape especially in the mountains.

If this happens we could see GUSTY SE winds to the mid 20’s and significant rain especially towards Los Barriles. If you are camped in an arroyo be ready to move fast and follow the forecasts carefully. Remember that even if it does not rain on the coast heavy rain in the mountains can send a sudden mass of water down arroyos.

(INVEST name means this storm is currently being monitored by the National Hurricane Center for the potential for future development. The NHC is a close partner of our company since we run the hurricane sensor network for them: https://weatherflow.com/professional-services/weather-networks/custom-designed-mesonets/the-weatherflow-hurricane-network/

West Coast Fog Brings Localized Winds

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West Coast Wind Blog: Unnamed tropical depression may impact Baja’s East Cape.

by Mike Godsey, mikeATiwindsurf.com

If you were flying several hundred miles south of Los Cabos this morning your view would look much like my photo above.

There is a CHANCE this tropical depression 93E.INVEST, currently several hundred miles SSW of Baja will lunge towards Baja’s East Cape on the weekend. If this happens we could see GUSTY SE winds to the mid 20’s and significant rain especially towards Los Barriles.

If you are camped in an arroyo be ready to move fast and follow the forecasts carefully. Remember that even if it does not rain on the coast heavy rain in the mountains can send a sudden mass of water down arroyos.

(The “INVEST” name means this storm is currently being monitored by the National Hurricane Center for the potential for future development.

WeatherFlow is a partner of the NHC and our Hurricane Network supports their life-saving mission.)

West Coast Wind Blog: Nagging clouds try to limit Baja local sea breezes

by Mike Godsey, mike@iwindsurf.com

The last few days have seen barely a trace of El Norte winds over the Sea of Cortez. But El Sargento, La Ventana and to a lesser extent still can see mild local sea breezes if there is enough blue sky to heat the inland valleys.

Unfortunately, yesterday Nov. 13 saw heavy clouds over the area that stopped the sea breeze from developing.  Today the same clouds mass is streaming from the SW with the subtropical jetstream. However the cloud band is more to the south. And the models suggest most of the band will move away from the La Ventana area later today. This would allow the local sea breezes to ramp up.

This satellite imagery shows those clouds as dawn sweeps over Baja.

West Coast Wind Blog: Star like fog pattern.

by Mike Godsey, mikeATiwindsurf.com

On the California coast we are used to seeing lots of weird fog phenomenon fog falls, razor-thin fog banks, hard-topped fog banks, fast appearing and disappearing fog masses.

But is rare to see a star like fog pattern in the satellite imagery of the clouds like we see out in the Pacific west of the San Francisco Bay Area today Nov. 4, 2019.

These trails were a mystery when they were first seen in 1965 in the TIROS V11 satellite imagery. But meteorologists quickly determined the cause of those tracks. The diesel exhaust from ships contains aerosol particulates that as condensation nuclei. More and more water molecules aggregate on these “seeds” until a visible cloud forms aloft trailing behind the ship. It also appears that sulfur dioxide from the ship’s exhaust makes the clouds more reflective and allows them to carry more water.

These ship trails are most best seen using near IR sensors on the satellite but sometimes, as in this image, the tracks are easily seen in visible imagery.

So why the star-like image? This area of the Pacific is an area where many shipping lanes cross and by chance today the trails made a star!

Of course, these days when opinions sometimes count more than facts I am sure that someone will see it as an omen that their favorite politician has been blessed by the heavens.

Here are images of many ship trails: ship tracks

 

Santa Ana winds see Round 3 and 4 this week.

by Meteorologist, Kerry Challoner Anderson

I have now lived in Southern California for over 20 years and still miss the traditional “fall” weather that is experienced if you lived in a higher latitude.  The joke is told though that California has it’s own 4 seasons – Earthquake, Fire, Flood and Drought.

If that is the case, then we can definitely say that we have moved full gear into fire season in the Southland as we shift into the see-saw of onshore/offshore flow.  So far we have had 2 rounds of sustained offshore winds that have initiated damaging fires.  Santa Ana wind events have become a new headache for us as not only do we suffer from dry, gusty winds, the fear of fires but also periods of precautionary power outages.

Well those headaches are not over and in fact this week sees rounds 3 and 4 quickly move in as a deep upper-Level Low carves out a path over the Central Mountains and pushes toward Mexico.  This will bring cold air down into Southern California.

Sunday morning starts with a +4.5mb/100 mile onshore flow but by the evening a cold front sinks southward, High pressure moves into the Great Basin and the flow  abruptly sinks to a -4mb/100 miles.  This system will move fast and by morning the gradient turns more easterly and continues to plummet to a strong -6 mb/100 miles.

Consequently, overnight winds ramp up and red flag warnings go into effect for Monday.  Models show much cooler air moving in which will mix down and create gusty conditions.   We start with NE winds which quickly turn ENE/E in the morning.

NAM 12 Forecast 12Z Monday, Oct 28, 2019

This system moves quickly out and by the afternoon, the gradients start to relax and the beaches are likely to see a reversal with some sea breeze activity.  The see-saw will tip quickly up and by Tuesday gradients are back to a +3.0 mb/100 miles. But not for long.  Another system drops into the upper Low and by Wednesday we head back down again, very quickly.  Models are indicating that we will be looking at offshore gradients at -9 mb/100 miles and another strong round of Santa Anna winds.

 

West Coast Wind Blog: La Ventana, Baja Sur sensors.

by Mike Godsey, mikeATiwindsurf.com

At the end of last season Ben installed a new sensor at Ventana Windsports. We did this because the old sensor at Baja Joe’s is sometimes in a partial wind shadow. Longtime Weatherflow customer John S. has installed a sensor on the Campground beach that covers that area nicely.

In recent years the North Pacific High has moved closer to the Baja coast in the winter and sometimes some of its westerly winds trickle across the Peninsula from the west coast. These westerly winds just aloft sometimes push the El Norte wind away from shore and make the winds inside weaker and shifty. I am hoping that John’s new sensor at the Club Cerralvo will pick up those winds in advance. Since this westerly wind phenomenon is most marked in the El Sargento to Hot Springs area be sure to check this sensor before driving to the El Sargento area to kite or do a downwinder. These westerly winds rarely occur when we have a pure local sea breezes but can occur anytime there is some El Norte wind.

Fall winds at Jalama

by Meteorologist, Kerry Challoner Anderson

As we start to move into the heart of fall we expect the North Pacific High to slide further south and that is exactly what we are seeing this weekend and the reason the Central Coast is enjoying such strong winds.  Saturday’s pressure maps showed a 1028mb High centered to the west of the Southern California coast resulting in strong coastal gradients.

Jalama’s waters were busy as winds topped 30 knots for much of the afternoon.

Though Jalama can receive strong days in the fall, it is also tricky to forecast at this time of the year due to the High-pressure systems that move into the Great Basin behind eastward-moving cold fronts. This sets up NNE/E winds that battle against the coastal winds.  The offshore winds are channeled through the East- West oriented canyons of the Santa Ynez range and can become very strong.  We begin to see these winds set up later this weekend.


As the Pacific High strengthens and moves a little closer to the coast, the Los Angeles to San Francisco gradient increases on Sunday to -8.5mb.  This will keep the coastal winds working. That will bring another strong day on Sunday for Jalama. But then the Great Basin High starts to exert its influence as the E/NE gradients start to climb.  By Sunday the Los Angeles to Daggett gradient starts to increase and  by Monday is at -5.1mb.  So we start to watch the NE winds increase and the battle begins at the coast.

Sunday sees the coastal winds win out so expect another solid day but then forecast is not so certain.

 

 

 

 

 

East Coast Wind Blog: Record-setting coastal low has major impacts on the Mid-Atlantic and Northeast US

by Kate Looney with imagery by Kate Looney and Mike Godsey

The first major coastal storm of the fall season took shape over the Chesapeake Bay on October 16th with a swath of moderate to strong E/SE winds building ahead of the storm and a powerful W/SW blast shaping up on the backside of the system.  Tens of thousands of people lost power and new surface low pressure records were set for October in several locations across Rhode Island, Massachusetts (including Boston), New Hampshire, and Maine (more on this later).

Let’s take a look at how the system evolved.

Looking at the surface analysis progression (courtesy of NOAA’s WPC), we see the beginning of a nice double-barreled low pressure system building at the surface at 2PM EDT the 16th across the Chesapeake Bay. This was in response to a splitting southern branch of the jet stream high above the surface (top left image).

By 00Z (8PM EDT, top right), the surface cold front has caught the warm front across the Delmarva region and a second occlusion has formed along the deepening coastal low. Moderate to strong SE to E winds were building from the Delmarva region all the way up into Massachusetts in response to the continued strengthening of this low.

The low continued tracking up the New Jersey coastline and up into the Rhode Island/Cape Cod area by 6Z (2AM EDT, bottom right) before rotating back northwestward just west of Boston as it rapidly “bombed out”, or strengthened quickly over a short period of time. The two different areas of surface low pressure eventually evolved into one exceptionally strong October surface low, hence the records set for minimum surface pressure.

Here’s a look at the water vapor imagery overlaid with surface pressure as the coastal low continues deepening from about 2AM EDT to 7:30 EDT the 17th:

WeatherFlow’s Carson Beach sensor reported a surface low pressure of 973mb just after 3am local time on the 17th as the low passed between Boston and Worcester, Massachusetts. 

As this low moved up west of Boston, the occlusion eventually began to choke the system. Eventually, the low slowed down and began to weaken across New Hampshire/southern Maine.

As a result, a large swath of very strong W to SW winds pummeled much of the Mid-Atlantic and especially the Northeast this morning, only finally easing up late this afternoon. The image below is an areal snapshot of WeatherFlow sensors across Rhode Island and Massachusetts about 10:30EDT with many sites maintaining near or above tropical storm force averages a good portion of the day and even stronger gusts well into the afternoon hours.

Another areal view of strong W/WSW winds with gusts noted as of 3:30 EDT.  Notice the gusts into the 50s/60s through eastern Long Island Sound, coastal Rhode Island, and southern Cape Cod waters.

The images below show the dramatic drop in surface pressure from WeatherFlow’s Carson Beach sensor in the Boston area from Wednesday to Thursday, hence the meteorological distinction of a “bombing” low (greater than 24mb drop in 24 hour period):

WeatherFlow’s Flow Map product nicely shows the cyclonic spiraling of surface winds into this low overlaid with surface wind observations. The surface low tracked right across the Concord, New Hampshire area around 8AM EDT, which also set a new record October low pressure of 973mb pending NWS verification.

Also of note about this storm-this post has thus far avoided the term “Nor’Easter” in association with this system. Although it did maintain a northeastern track as coastal lows often do during the fall and winter seasons, a classic Nor’Easter is named because of the strong NE winds that develop ahead of the system across the Mid-Atlantic and Northeastern US. In this case, due to the track of the coastal low much closer in to the coastline, winds ahead of the system remained out of the SE to E.  Really it’s a moot point though as no matter what you call it, it was definitely a record-setting system for October.

Bottom line, the track of the low plays a big role in how the wind field evolves for a very large area.

Because of the necessity in an accurate forecast track and it’s implications on the wind field, these systems can be quite tricky to forecast on days when adventurous sailors, surfers, and kiters may want to take advantage of strong winds. WeatherFlow meteorologists may include a statement like “forecast remains subject to change/highly dependent on track of the low/winds may drop quickly” to convey the uncertainty in these situations until a more clear track is known.  Large swings in speed and direction can happen over the course of an hour or two for areas where the surface low passes overhead or close by, somewhat like the calmer winds in an eye of a hurricane.

This image below from WeatherFlow’s Kalmus sensor in Cape Cod highlights the potential for rapid changes in winds:  You can see around 1AM that winds begin to drop out to mid 20s briefly after building to nearly 50mph. This is followed by a steady build and almost 180 degree reversal in direction from ESE to WSW due to proximity of the surface low swinging by just the west. Quite the variety in speed/direction over a few hours!

 

 

 

 

 

 

 

 

 

 

A more dramatic example can be seen below at Weatherflow’s Pt. Judith, Rhode Island sensor, where winds went from 50mph to near 10mph in about an hour! Steady veering to the SW/WSW ensued with a quick build back to very strong upper 40s/low 50s with passage of the low.

 

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